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LEYLAND
APRIL 1971
THE JOURNAL
OF THE INSTITUTION
OF HIGHWAY
ENGINEERS
I
4
THE JOURN ....L OF THE INSTITUTION
OF.;.HIGHW ....YlENGINEERS
....PRIL 1971
,
The Journal of the
Institution of
Highway Engineers
April 1971
Volume XVIII Number 4
Contents
The Servicing
A. Darlot
Arrangements
for the Paris.Rungis
Market
7
Anchored Diaphragm Walls in Sand - Some Design and
Construction
Considerations
G. S. Littlejohn, B.Sc., Ph.D., M.LC.E., F.G.S .•
B. J. Jack. M.LStruct.E., and Z. J. Sliwinski. M.LC.E.
15
Ntw Plant. Equipment and Materials
31
Institution
33
Matters
I
~
The Institution
~.
of Highway Engineers, 14 Queen Anne's Gate, London SW1
President: H. K. Scott, D.B.E., B.Sc., F.I.C.E., F.lnst.H.E.
I
Secretary: M. J. Hall, M.A., F.C.I.S.
The Journal of the Institution of Highway Engineers is published monthly
for the Institution of Highway Engineers by Industrial Newspapers Ltd,
All editorial communications
should be addressed to The Editor, The
Journal of the Institution of Highway Engineers, 14 Queen Anne's Gate,
London SW1 Telephone 01 -839 3582
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APRIL 1971
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or
roill
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Subscription Enquiries
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John Adam Street, London WC2N.6J H. Telephone 01-839 6171
(1"~1J\..11Qo11'
THE JOURNAL OF THE INSTITUTION
OF HIGHWAY
ENGINEERS
S
Howto assess costs
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Computation of vertical sections along specified lines.
Interpolation of terrain vertical profile and crosssections from data in the form of surface heights of
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6
THE JOURNAL
Of THE INSTITUTION ..Of HIGHWAY
ENGINEERS
APRIL 1971
Joint Meeting Institution of Highway Engineers! Socie te des Ing;mieurs Civi/s de France (British Section)
The Servicing Arrangements for the
Paris-Rungis Market
A. Darlot
BIOGRAPHY
Andre Dar/ot began his career in 1938 when he took up the
post of Agricultural Engineer with the National Agricultural Institute. From 1940 to 1945 he served in the
armed forces and was present at the landings by the
First French Army in Provence.
In 1945 he joined the National School for Rural Engineering as an Engineer and later became a Refrigeration
Engineer with the French Institute of Industrial Refrigeration. From 1948 to 1957 he worked in Morocco, first with
the Department of Assessment and Rural Engineering,
and then with the Directorate of the Centre for Research
and Experimentation in Rural Engineering at Rabat. He
was appointed Engineer-in-Chief in April, 1954.
He returned to Paris in 1957 as Chief of the technical
section of the General Directorate for Rural Engineering
and Agricultural Hydraulics and from 1959 to 1960 was
responsible for the training of engineers in rural works.
In 1963 he took up the post of Director of Rural
Engineering and Agricultural Hydraulics at the Ministry
of Agriculture in Algeria and two years later was appointed
Engineer General.
Since 1965 he has been Joint Director General, Societe
d'Economie Mixte d'Amtmagement et de Gestion du
MarcM d'lnteret National de la Region Parisienne.
SU M MARY
The servicing arrangements for a market. a dross-roads
where merchandise and people meet, is of fundamental
importance.
The Rungis Market, which handles 1,600,000 tons per
year has been developed on an area of 200 ha, close to
Or/y Airport and only seven km from the gates of Paris. It is
APRIL 1971
served by four main radial highways. of which two are
motorways, joining d to the Paris peripheral boulevard.
and also a ring road. It is provided with'extensive railway
yards directly linked to the S.N.C.F. network.
The extent of the available area (more than 500 ha)
has made possible, simultaneously wdh the market. the
development of an important complex comprising a warehouse sector. a hotel and tourist centre, a retail commercial
centre. a residential area, a commercial road vehicle
station and an industrial area; the traffic for this complex
has justified the construction of major works on highway
and railway links.
Its internal arrangements are based upon a rectangular
grid of very wide highways connected to a ring road
, which communicates with the five entries and. the four
exits. The mesh of this highway network accommodates
parking areas and sales buildings. the shops of which are
directly accessible to the supply and despatch vehicles.
The whole of the highway and railway loading platform
permit the acceptance of 2,000 lorries and 800 railway
wagons. The number of car parking places is 10,000.
More than 27.000 highway vehicles use the market
on peak days. the arrangements for which allow peak flows
of 3.500 vehicles per hour at entries and exits.
The geographical location of the market. the quality of
its servicing arrangements. the organisation of internal
traffic movement and the general concept of its develop'ment suit its present activity ideally and ought to permit
it to adapt itself easily to any evolution in future methods of
distribution.
This Paper will be given at a meeting of the Institution and the Societe de Ingtmieurs Civils de France
(British Section) at the Institution of Civil Engineers,
GreaeGeorge Street S. W.1. on Friday, May 7th. 1971.
THE JOURN ....L Of THE INSTITUTION
Of HIGHWAY
ENGINEERS
7
The Servicing Arrangements for the Paris-Rungis Market
The maintenance, at the heart of the capital, and away from
railway stations, of a wholesale market which has to bring together, within a particularly densely built-up area, more than
1,500,000 tonnes of perishable goods each year, in order to
redistribute them later within the Paris built-up area, was unsatisfactory for town planning, for economics, or for ttie firms
concerned.
The centre of a tOWnis not a particularly suitable location
for the acceptance, in good condition, of the enormous volume
of traffic of a wholesale market of this magnitude. This traffic
seriously interferes with local traffic engaged in other economic
activities. The cost of transport, servicing and mobility so as
to maintain an activity within a non.functional framework
is considerable, whilst the economic value for the whole of
the areas thus occupied is low_ Finally having enterprises w;t!lin localities unsuited as much by their shape as by their servicing needs and their environment, constitutes an insurmountable obstacle in their development towards an organisation
RUNGIS
The Table indicates the importance of the movement of
merchandise and people, recognition of which is necessary in
order to appreciate the dimension of the problem.
It is therefore a question of:
(i) locating the market at a cross-roads on the lines of com.
munication, permitting easy access of supply vehicles (lorries
and railway wagons) from all directions, of buyers and employees. vehicles and of the people brought in by public
transport.
(ii) arranging the entries, exits, traffic movement and parking
areas, and organising the provision of transport services by
public. so as to be able to absorb instantaneous and very
large peak flows without difficulty.
(iii) considering the eventual possibility of a growth in' the
use of aerial transport both for merchandise and for distant
clients.
(iv)
MARKET
siting and planning the buildings so as to permit off-
- TRAFFIC
1970
PRODUCE
Fruit and Vegetables
Wholesalers
Number affirms
Flowers
Producers
Dairy
Produce
Sea
Produce
440
100
117
447
(at peak)
Annual tonnage
1,230,000 t
Daily peak tonnage
90.000 t
248
182.000 t
107,000 t
212,000
parcels
(approx
15,000 t)
parcels F
(approx
3,200 t)
6,800,000 pots
1.200 t
1,000 t
Arrivals by rail per cent
30 per cent
10 per cent
16 per cent
90 per cent
Arrivals by road per cent
70 per cent
90 per cent
84 per cent
4 per cent
100 per cent
6 per cent
A~tive population
12,000
Effective number of
buyers
16.000
Number of vehicles
entering the market
on peak days
27,000
Peak hourly maximum
at entries in vehicles
per hour
3.500
adapted to the needs of modern commerce.
It was therefore decided to transfer this market to a new
location which answered the conditions required for its proper
functioning.
A wholesale market ought above all to satisfy two
objectives:
(i) it should be able to offer the best conditions as a centre
for the transfer of merchandise in transit from the places of
despatch to retail points;
(ii) it should be easily accessible to buyers and to the
personnel of the firms which are installed there, able to
accommodate them and permit them to get to the sales areas
by the most convenient way possible.
OF THE INSTITUTION
700
2.260,000
8.000 t
THE JOURNAL
Producers
(at peak)
Arrivals by air per cent
8
Wholesalers
and Plants
Of HIGHWAY
ENGINEERS
loading and transferring to the sales areas and the removal
of goods with the shortest possible delay and hindrance,
at minimum cost.
(v) effecting a concentration of sales areas, on as small an
extent as possible, and arranging these so as to make them
easier for access by buyers, whilst not damaging their com'TIercial attraction in the present phase where bulk enterprises
are numerous and often of limited size, and where the buyers
for the most part come into the market daily and pick up
their goods themselves.
(vi) planning the installations, nevertheless, so that they may
be adapted to possible d...velopment in the methods of com.
merce characterised by a growing development of assorted
orders and by a major concentration of enterprises.
APRIL 1971
The Servicing Arrangements for the Paris-Rung;s Market
I
EXISTING RING ROADS
Reproduced
by courtesy
I-IIJ-_O-_::I-_::I-_::I-_::I-_
PROJECTED
of Michelin
et Cie,
Paris
RING ROADS
PROJEC TED METRO EX TENSION
ROUTES NATIDNAUS
Figure 1. Map of Paris central area showing existing and projected road and rai/links. Area marked indicates position ot market.
THE SITE
An area of more than 500 ha, practically uncommitted was
found only 7 km from the gates of Paris, ideally served by
road and rail and near to Orly Airport.
The choice of site could therefore be made without very
much hesitation.
The available space permitted the construction, simultaneously with the market which occupies 200 ha, of a complex
comprising:
(i) a sector
for warehouses and foodstuffs industries
(SENIA) on an area of 115 ha, allocated to firms from the
foodstuffs sector serving the Paris built-up area: warehouses
for distributive chains, transport of foodstuffs, wholesalers in
dry and liquid groceries. dairy industries, warehouses for
chain stores and restaurants, etc., which together with the
APR.IL 1971
market itself provide a comprehensive distribution centre for
foodstuffs incorporating all the ancillary activities.
(ii) a tourist and hotel centre which can accept, in an area
of 35 ha, hotels, restaurants, entertainments, travel agents,
congress halls and exhibition buildings. This centre is linked
to the market by a bridge which crosses the Orly branch of
the motorway and contains a shopping gallery and restaurants.
(iii) a regional business centre where, on an area of 20 ha,
a retail commercial centre of 120,000 sq metres floor area and
office buildings representing 30,000 sq metres of available
area as well as 7,000 parking places, has been built.
(iv) a residential area of 27 acres which will contain 2.300
dwellings.
(v) a commercial road vehicle station occupying an area of
60 ha.
THE JOURNAL
OF THE INSTITUTION
OF HIGHWAY
ENGINEERS
9
The Servicing Arrangements for the Paris-Rungis Market
.~
I
OE
fll.JNQl5
I
••
Figure 2. Overall layout of the Rungis Market.
(vi) a commercial vehicle centre which within an area of 20
ha. has all the services required by the transporters using
the commercial road vehicle station. '
(vii) an industrial and commercial area which occupies an
area of 55 ha where there is a collection of buildings for use
as warehouses, workshops or offices. '
This complex, which will provide work for a population of
50,000 people, guarantees a very good rate of return On the
enormous infra-structure works which have bee.n necessitated
by the creation of the market: diversion of aqueducts and
high-tension lines, sewerage system, water and electricity
supply. The volume of the traffic which it generates, to
which must be added that of Orly Airport, has justified the
construction of the road and railway links of such magnitude.
Rcproduced
•
1::1
I
..
I
a
by courtesy o[ Horiz.ons de France, Paris
will in the fl)ture permit the by-passing of the built-up areas
of Thiais and Choisy.
'
As far as the railway arrangements are concerned, Rungis
is linked by a branch line 7 km in length to the Villeneuve Saint
Georges railway station. This is on the line from the southeast and the south-west upon which 75 per cent of the
supplies for Rungis arrives. It is, linked to the North Station
and the East Station by the Grande Ceinture.
As for the aerial freight terminal at Orly Airport. this is only
3 km from the centre of the market to which it is linked by the
.Orly Branch of the South Motorway and the RN7.
'
The highway arrangements are provided by three major
radial routes: the South Motorway and the RN 7 which
interconnect Paris and Marseilles and the RN 20 which
runs from Paris to Orleans and Toulouse. Since December
23rd, 1970 access to Paris has been still further improved by
the opening of Motorway H6, which duplicates the South
Motorway between the Gates of Paris and Rungis-Orly and,
in the n'ear future, two new motorways will give further access
to the market. Motorway A5 (Paris-Melun) and motorway
A I0 (Paris-Chartres).
1
j
The capacity of existing radial highways, including seconuary roads not mentioned, is 17,000 vehicles per hour, whereas
the traffic flow on these same highways (traffic generated by
the Rungis-Orly complex and other traffic) should attain
i5.GOO vehicles per hour in 1974. This capacity is th:lreforc
sufficient for the moment.
These radial highways decant on to the new peripheral
boulevard, which already links the north and t,he south of
Paris on the east. The part on the west ought to be finished
around 1974. Also a ring road of larger radius crosses the
market-the
RN 186. This ring road wiII be altered to a
motorway (A86) and the first section to motorway standard
has already been built between Fresnes and Thiais, whilst a
spur of this motorway, which crosses the market on a viaduct,
10
THE JOURN~L OF THE INSTITUTION OF HIGHWAY ENGINEERS
I
I
'!
Figure 3. The bridge over the RN 186 which gives ifllercommunication between the reception area and the market.
In the middle distance a gyratory interchange between the
market and the railway station.
APRIL 1971
The Servicing Arrangements for the Pa~is-Rungis Market
---
--~ --
-----------
Figure 4. The Bel/e-Epille interchange between the RN 186
and the RN 7.
HIGHWAY AND RAILWAY CONNECTIONS
The linking of the different elements of this complex to the
highway previously described is, or will be, guaranteed by the
following works:
(i) Fresnes Interchange, which lies between the two bridges
taking the two carriageways of the RN 186, over the H6, is to
be the location for the two bridges for the carriageways of the
future A86 motorway. This interchange, which is only half
built, will be completed later as a full clover leaf.
Oi) A diamond interchange between RN 186 and the new de.
partmental road CD 65, the alignment of which is more or
less parallel to that of the OrIy Branch of the South Motorway.
(iii) the interchange linking the RN 186, which is a uni.
directional ring road, allowing connection from the market to
the commercial road vehicle station.
(iv) a full clover leaf interchange between the RN 186 and
the RN 7.
(v) two half interchanges to the east of the RN 7 between the
RN 186 and the new highways linking SENTA to the regional
business area and the residential area.
(vi) a series of bridge crossings of the RN 186, the RN 7 the
South Motorway and the Orly motorway.
Thus it is possible to get to the market:
Figure 5. The diamond interchange between the RN 186 and
fhe CD 65.
APRil
1971
Figure 6. The railway marshalling yard and unloading bays
for fruit and vegetables. 1/1 the foreground the hump sorting
bridge over the RN 186.
(i) when coming from Paris or from the south, directly b}
motorways A6 and H6 and by RN 7; by using the RN 186
when arriving via the RN 20; and finally by motorways AS
and AlO,
(ii) when coming from the east, directly by RN 186 by using
the RN 7 at the end of the journey,
(iii) when coming from the west. directly by the RN 186,
(iv) when leaving the Market for Paris directly by motorways H6 and A6, by the RN 7 or by using the RN 186 so as
to rejoin the RN 20, and finally by motorways AS and AlO.
(v) for the south, directly by the RN 7 or by using the
RN 186 so as to rejoin the motorway A6 or RN 20 and finally
motorways AS and At 0,
(vi) for the east and west, directly by the RN 186.
The railway link arrives at a reception yard situated to the
south of the market and allows for the reception of 10 to
Figure 7. Part view of the fruit and vegetable unloading bays.
THE JOURNAl
OF THE INSTITUTION
OF HIGHWAY
ENGINEERS
II
The Servicing Arrangements for the Paris-Rul1gis Market
12 complete trains arriving one after the other at a few minutes
interval on 8 parallel lines. From this yard the wagons can be
directed and sorted into the market by crossing over the
RN 186 on a hump bridge towards the commercial road
vehicle station or the particular branches which serve the
whole of the SENIA lots.
PUBLIC TRANSPORT
Independently of motorbus routes which use the various
highways previously mentioned, and which pass close to the
market or which end on the terminal situated at the gates or
within the market, the service arrangements for the Rungis
complex are assured by passenger trains from OrsaySt.
Michel and Austerlitz stations which terminate at the rail.
way station of Rungis Bridge. located at the intersection
of the railway link line and RN 7. Passengers are picked up
from this point by a shuttle service of motorbuses. A plan now
being studied is aimed at providing communication between
the various sectors of the Rungis complex, Orly Airport and
Rungis Bridge Railway Station by means of linear electric
motor vehicles suspended from a rail.
The section between Paris and Rungis-Orly will in the future
be linked by'a metro line which would start from the Porto::
d'1talie and will serve the whole complex via three railway
stations located at surface level: at the regional business
centre, the Orly industrial area centre and the Airport.
THE INTERNAL ARRANGEMENTS OF THE MARKET
The servicing of the entry and exit points of the market
having been completed satisfactorily both for merchandise ana
people, it was important to complete internal developments to
a degree which would satisfy the conditions previously given,
namely:
(i) facilitate traffic movement at entries, at exits and within
the market.
(ii) facilitate parking.
(iii) enable rapid unloading operations, supply to the sales
areas and the removal of merchandise at minimal cost.
(iv) provide a favourable arrangement within the present commercial system yet capable of being adapted to its develop.
ment.
Two principal and three secondary entries permit the
simultaneous handling of 28 vehicles. The parking fees are
paid at the entries, the latter being equipped with toll gates
using magnetic cards which allow a high rate of entry, The
equipment adopted permits easy passage of an hourly peak
flow greater than 3,500 vehicles. In all cases the entries are
preceded by sufficiently extensive waiting areas so that the
queues do not disturb the general traffic movement.
The four exits allow easy passage of comparable peak
hourly flows.
The entries and exits are linked by a peripheral ring road
which is uni-directional and has six traffic lanes; within'it a
Figure 9. One of the West parking areas. On the right, and
over the Orly Motorway. the bridge-restaurant, which allows
illterconnection between the Market and the hotel area.
rectangular grid of highways services the different buildings
and the parking areas, none of these is less than seven metres
wide for anyone direction of traffic.
The space between buildings is 43 metres from loading
platform to loading platform for the large sales buildings,
which contain the most important firms and from 23.28 metres
for the small buildings and the producers' stalls, which
generally deal with vehicles of smaller dimension. These spacings are sufficiel)t to allow easy traffic flow in both directions
whilst vehicles are at the loading platforms.
Sales buildings, patronised by the customers, have shops
situated on either side of a central sales alley reserved for
the use of buyers and equipment servicing the shops, The
overall arrangement is concentrated in a central nucleus whilst
the major parking areas occupy the peripheral zone lying
between this nucleus and the outer ring road.
Independent of the parking arrangements at loading platforms there are other parking areas between the buildings and
in the central open areas of certain main traffic roads.
The buildings used as warehouses or intended for wholesalers have been re-grouped in the southern part of the market
and have much smaller parking areas for they are not normally
used by the buyers.
The total number of parking spaces is 10,000. The total are ..
of highways and car parking areas is equivalent to that of
60 km of dual three-lane motorway.
A traffic control post installed on the eleventh floor of the
administrative building, allows surveillance and regulation
of traffic at entries and exits. It has for this purpose six television screens linked to six adjustable cameras arranged at
critical points. It is also in radio contact with a main traffic
control post situated near to the Porte d'Orieans. Its recording'instruments and counters are linked to traffic counters
Figure 8. The West entry to the Market.
12
THE JOURNAL
OF THE INSTITUTION
OF HIGHWAY
ENGINEERS
APRIL 1971
t
The Servicing Arrangements for the Paris-Rungis
..
~.
. "I
I
r
.,
D
--
Figure 10. The television screen at the traffic control post.
placed at the entries and exits and can determine the rate, as
well as the total number, of vehicles passing through the
entries and the exits at any instance.
The supply operations for railway wagons and lorries and
for the removal of goods are particulary important because
they must be executed quickly making the maximum reduction in intermediate handling so as to produce the least pas.
sible cost.
The supply trucks can deliver their merchandise either
directly at the shop loading platforms, or at the special sorting
bays when the number of lots being delivered is too great
to be discharged by successive stops.
The total length of these loading platforms permits simultaneous unloading of 2,000 trucks.
The railway wagons can be discharged either when they
are being sorted along the loading platforms of the main
central station for fruits and vegetables (length 2,300 metres) ;
the common loading platform (340 metres) ; the sorting loading platform of the B.O.F. (length 450 metres); the seaproduce loading platform (length 500 metres) the flower load.
ing platform (length 200 metres) or when it is a question of
complete wagons for a single consignee, in the lanes alongside
the buildings (length 1,500 metres) or along the platforms
bordering the warehouses (length 1,800 metres). Taking
account of the double track alongside some loading platforms,
the present installations permit the acceptance of the 800
wagons unloading with opportunities for an increase of up
to 1,000 wagons. The two tracks west of the fruit and vegetables buildings wHl be capable, as the need arises, of development to accept three parallel tracks in place of the sales
alley.
In spite of the proximity of unloading platforms for mer.
chandise arriving in bulk the expenses arising from these
terminal servicing supply arrangements are very high. This
Figure 11. Part view of the /mit and vegetable bllildings.
APRIL 1~71
Market
is because of the numbers of personnel necessary for unloading, the breaking down into lots, and delivery to the shops,
a1l in a relatively short time; merchandise from vehicles can
contain on average more than 15 lots. The cost of these
services is, for fruit and vegetables, 40 francs (£3) per ton, or
about 3 per cent of the cost of the produce, and for sea
proc','Jce, 45 francs (£3.34) per ton or about 1.2 per cent of
the cost of the produce. The expenses which the users of the
market have to bear under the form of rent for premises and
parking fees (these rental costs include the financial expenses,
the maintenance of the road network, the buildings and the
railway network, the cleansing of the market, public lighting,
the running of the administrative services of the management)
only represent on average 1 per cent of the cost of. the produce
dealt with in the market.
The high cost of these services is a result of the limited
size of the wholesale enterprises in the market, which are too
great in number, and splitting of consignments amongst a great
a number of recipients so that senders may better share
their risks. The delivery of merchandise in complete vehicles,
together with the development of container transport, permitting direct unloading at shop loading platforms, with minimum
servicing arrangements, ought, in future, to allow for a
major reduction in costs.
As far as the operation of despatch is concerned, the layout
of the buildings permits the removal of goods directly at the
shop platforms by the buyers' or deliverers' vehicles, except
Figure 12. Internal road between the fruit and vegetable
buildings.
in the sea food and cut flowers building where the multiplicity
of small wholesalers has led to the installation within large halls
of stalls which are not directly accessible from the outside.
Whereas, in the case of flowers, the buyers can mostly remove
the lots themselves, in the case of sea foods removal necessitates intermediary handling which costs 35 francs (£2.63) per
ton or 0.9 per cent of the value of the produce. Concentration
of wholesale firms will, again, permit substantial savings.
Despite everything the cost of terminal servicing for supply
and despatch at Rungis is much lower than that at the central
Hailes in Paris where it was necessary not only to transfer
goods between quite distant stations but also to move this
merchandise across a maze of streets cluttered up with stalls
and then to the buyers' vehicles which were scattered around
within a radius of 1,000 - 1,500 metres. The savings realised
in this field alone at the Rungis Market represent about half
the total annual cost of the new market.
THE JOURNAL OF THE INSTITUTION OF HIGHWAY ENGINEERS
13
The Servicing Arrangements for the Paris-Rungis Market
The grouping of buildings used by the customers within a
comparatively restricted space, the arrangement of sales
alleys for the circulation of buyers and the importance of
park.ing areas, has proved more convenient and the free
movement now available is conducive to present day methods
of commerce.
Direct access from shops to platforms or loading or unloading areas, so far provided or anticipated for the future, the
width of traffic lanes, the developing character of the internal
arrangements of buildings, the existence of an important
financial reserVe of land available from the peripheral park.ing
areas will also permit an easy adaptation of the arrangements
made, to new methods of commercialisation. A lesser number
of buyers and the development of delivery on demand, as
well as any extension of the covered areas which may become
necessary is a future hope.
CONCLUSION
The results recorded since the opening of the market in
March 1969 (bearing in mind that studies had started in 1961)
confirmed the value of the choice which had been made as
far as the site of the market was concerned, and the concept
of the arrangements made for servicing and internal organisation. The tonnages dealt with are greater by 20 per cent than
those which were handled by the central Hailes and attendance
14
THE JOUR~AL
OF THE INSTITUTION
OF HIG~WAY
ENGINEERS
by buyers also shows a net growth of the order of 10 per
cent, because, for reasons of convenience of access and parking, not only Parisian buyers, but alsn provincial buyers within
a radius of 200 km of Paris, are becnming more and more
numerous.
The quality of highway, railway and aerial facilities by
which the centre for the distribution of food stuffs at Rungis
benefits, is allied to the importance of the range of products
with which it deals - this will shortly be enlarged by the
transfer of the Meat Market - and will give the market great
international potential and the basis for this is now being
laid down.
It was logical, in the concept of a market which is above
all a vast cross-roads, to give pre-eminence to the transportation and traffic problems and to re-group, in a single location,
the greatest possible number of complementary activities. as
much to permit the growth of commercial attraction as to
justify, on the economic plan, the very important developments of the road network, and it appears that the "content"
responds well to the needs. There now remains-and it is an
essential task - to develop the "content", that is all the
enterprises which use this market, so as to exploit the possibilities offered. This then is a problem which is no longer
technical but human and because of this much more difficult
to resolve.
APRIL 1971
Anchored Diaphragm Walls in Sand-Some
Design and Construction Considerations
G. S. Littlejohn,
B.Sc., Ph.D., M.I.C.E., F.G.S., B. J. Jack, M.I.Struct.E.,
G. S. Littlejohn
M.I.C.E.
Z. I. Sliwinski
B. I. lack
BIOGRAPHIES
Dr Littlejohn is a graduate of the Universities of Edinburgh
and Newcastle upon Tyne and is at present a consultant
with Cementation Ground Engineering Ltd. He is responsible for research and development in ground engineering
with particular reference to geotechnical processes.
For the last five years he has been concerned with the
development of anchor design and construction techniques in a wide range of soils and soft rocks.
Mr Jack has been a Senior Design Engineer with
Cementation Technical Services Division for the past
seven years and his work has involved the design of
marine structures and specialist foundation problems.
For the last four years he has specialised in computer
aided solutions to civil engineering problems and is now
in charge of the Company's IBM 1130 computer which
handles the technical computing requirements of the firm.
Mr Sliwinski graduated from Warsaw Technical University in 1928 and is a former director of Braithwaite Founda~
tion Company where he was in charge of all overseas work.
He joined Cementation in 1964 and was later appointed
Deputy Manager of the large diameter pile and diaphragm
wall section. He is at present working in a consulting
capacity with Cementation Piling and Foundations Ltd.
and Z. J. Sliwinski.
Also shown are the results obtained by the generally
used methods.
The new method has the advantage of being a repetitive
single-tied wall design. and it is amendable to varying soil
strata which has always been a problem when implementing the trapezoidal method.
The Paper then describes the main design and stability
considerations associated with trench excavation under
bentonite, and gives recommendations covering the main
requirements for tremie concrete for load bearing diaphragm walls.
Methods of estimating anchor location, overall stability
and load carrying capacity with relevant safety factors, are
iJJustrated. Anchor construction stages are described
together with the post-tensioning
procedures and
corrosion protection normally recommended for sand
anchors. Finally, the influence of prestressed tie-backs on
the lateral movements and settlement of the retained soil
mass is discussed.
The Paper is divided into four parts. Part I. WaJJDesign,
is by Mr B. J. Jack. Part 2. WaJJConstruction, by Mr Z. J.
Sliwinski and Parts 3 and 4. Anchor Design and Anchor
- Construction by Dr G. S. Littlejohn.
Introduction
SUMMARY
The Paper introduces a method of estimating the anchor
loads required to support a multi-tied continuous waJJ.
It involves a procedure which calculates the position and
magnitude of a resultant tie at any stage of excavation
by treating the wall as a single tied structure.
Comparison of designs carried out by the Cementation
method and experimental work indicates that the results
obtained provide a good estimate of the horizontal forces.
APRIL 1971
Due primarily to the increasing tendency to design buildings
with a number of basement floors, the formation level of the
excavation being often at considerable depth below the foundations of the neighbouring properties, methods of temporary
and permanent earth support have been developed in recent
years to keep pace with the increased efficiency of modern
construction.
The diaphragm process of constructing load-bearing walls
in the ground prior to main excavation, based on the use of
THE JOURNAL OF THE INSTITUTION OF HIGHWAY ENGINEERS
15
Anchored Diaphragm Walls in Sand-Some
Design and Construction Considerations
bentonite slurry to hold open the excavation until concrete has
been placed, is such a method. The technique is of special
value in built-up areas since diaphragm walls may be constructed in very close proximity to existing buildings, where
other methods of piling and trenching may be ruled out by
restrictions on access and noise, and where a wall with high
structural efficiency and few joints is required. In addition,
settlements of the soil surrounding the excavation are minimised due to the ability of the bentonite to reduce loss of
ground during wall construction and the strength and stiffness
of the wall itself. In some instances, the diaphragm wall may
serve as the exterior wall for the permanent structure.
In many cases it is possible to achieve appreciably increased
efficiency, as well as reducing settlements during the main
excavation, by using prestressed soil anchors for supporting
the wall. Anchors provide intermediate points of support at
one or more levels, thereby reducing bending moments, with
Figure 1 General- view of anchored diaphragm wall. By
courtesy of Trollope and Colis Ltd., - Guildhall Precincts
Development.
consequent reductions in dimensions, reinforcement and depth
of the toe of the wall. Interior struts can be eliminated which
in turn brings quite large economic and constructional
advantages. This is especially so in cramped excavations, in
wide cuts or on sites where the contract programme calls
for the use of efficient excavation and construction machinery.
(Figure I)
Although both diaphragm wall and soil anchor techniques
have been proved since the late 1950's, there is little published
information on walls supported by prestressed tie-backs. The
purpose of this Paper is to discuss in some detail the main
design and construction aspects associated with an anchored
diaphragm wall in sand, which are likely to be considered by
th~ practising engineer. The Paper also emphasises that whilst
design procedures. for' excavations supported by soldiers and
planking are readily available, the design of continuous walls
supported by tiers of prestressed and inclined soil anchors
entails a fundamental difference because construction methods
playa more significant part in determining the forces and displacements which result in the wall and anchors,
1. WALL DESIGN
General Considerations
When studying the support of excavations the following topics
have to be considered.
(I) The type of soil to be retained.
(2) The type of wall to be used.
(3) The method of design.
The first stage is the collection and interpretation of soils
data. In this connection the design engineer has to decide the
type of soils investigation required to facilitate the design of
the permanent structure and provide the construction engineer
with sufficient information to build the work. These two
16
THE JOURNAL OF TH~ INSTITUTION OF HIGHWAY ENGINEERS
separate requirements can quite often lead to different soils
tests and affect the distribution of boreholes throughout the
site. The role of the soils engineer in this kind of problem
cannot be over-emphasised, he and the wall designer should
co-ordinate from the initial concepts of the work right through
to final design stage and even into the construction period.
Once the soils investigation has been carried out and test
results are available, both. for the permanent and temporary
works construction,. the design engineer must choose what
type of wall is to be employed for the support of the excavation. At the moment a wide variety of methods is available,
varying from planking and strutting through to the use of
diaphragm walls which can be incorporated in the permanent
structure. Having chosen the methOd or a number of methods
of retaining the soil the design engineer is now faced with the
problem of how to determine the structural stresses, tie bar
forces, etc.
The design of walls to support deep excavations is an art
rather than a science, but nevertheless it is essential that a
logical approach is taken in the design. Shallow excavations
can utilise cantilever or single-tied walls for which much
valuable information has been supplied by Rowe(J) in his experimental work. By a careful study of the soil parameters,
wall flexibility, etc. in these designs the engineer can make
a fair estimation of the behaviour of the structure in practice.
At present little direction is avai]able on continuous multitied wall design, where cable anchors or struts are incorporated
in the support system. For deep walls using planking and
strutting the methods recommended are generally based on
the "trapezoidal" pressure distribution which was originated
by Terzaghi. This method was established from experiments
carried out on an excavation in Berlin through cohesionless
material supported by soldier piles and planking. It should be
remembered, however, that the pressure distribution was based
on an envelope enclosing assumed parabolic distributions at
each stage of excavation, the size and shape being calculated
equal to the magnitude and distribution of the actual measured
strut forces. This trapezoidal pressure distribution is valid only
-under certain conditions since the actual earth pressures are
a function of the degree and type of freedom for lateral expansion of the retained soil.
It is evident that the soil pressures existing behind contiguous piles, steel sheet piling and diaphragm walling will be
different to those of a soldier pile construction as the earth
support provided by the material to be excavated at any
stage acts on -the full wall face and not on small areas, which
is the case when using soldier piles. The bearing pressure will
be less, reducing the wall's lateral movement, thus effecting the
re-distribution of earth pressure.
Design Parameters
Rowe's work on single tied walls has clearly shown that
one of the most important factors in this type of design is
the wall's llexibility, which tends to reduce the maximum
bending moments and increase the tie bar forces through
arching of the ground. It is quite logical that the smaller the
deflection, the smaller will be the arching effect and it is
reasonable to expect that where the wal] continues below the
excavation level, a high degree of fixity will produce a less
effective span, a smaller wall deflection and less redistribution
of soil pressures due to arching. It therefore seems inappropriate to use the "trapezoidal" method when designing walls
of this type, because in these instances, a more triangular
pressure distribution would be expected. If an extreme case
is considered where a continuous diaphragm or sheet piled
wall is constructed in the ground and struts are inserted at
close centres as the excavation proceeds, ]ittle or no redistribution of soil pressures will take place and the resulting
pressure diagram will be of a triangular form. The actual
values will depend on the type of wall used. In the case of
steel piling, where the wall is driven into the ground, the
pressures before excavation at either side may be considered
"at rest", whereas with diaphragm wall construction, where
an excavation is opened up and the ground stabilised by the
APRIL 1971
.
Anchored Diaphragm Walls in Sand-Some
use of bentonite, some yielding of the soil occurs, tending to
reduce the "at rest" pressures to those approaching the active
state. Therefore, even within the field of continuous retaining
walls, different parameters will have to be employed depend in;,:
upon the type of construction, spacing of props etc.
The stress distribution, which governs the design, depends
upon the walling material used, the method of construction and
the centres at which the struts or ties are installed since it is
the effective span at anyone stage of construction which will
determine the deflection, and consequently the re-distribution
of soil pressures. One of the most important factors in this
respect is the strength of the soil in front of the wall mobilising
the passive pressure as this determines the additional dimension below excavation level making up the effective span.
In the case of multi-tied walls, as stage by stage excavation
proceeds the passive pressure producing the effective span at
anyone stage can be assessed approximately, but as excavation proceeds past a particular stage the ground which was
restraining the wall is removed and further deflection can take
place. The amount of passive resistance built up at any intermediate stage, when removed, must be added to the active
pressures on the wall, since in the previous stage it was subtracted to produce the resultant pressure diagram and hence
the tie bar forces above. If this is done then the final soils
distribution achieved will be of a triangular form with
exaggerated "bumps" at each tie level, the amount of
additional pressure at a tie being dependent upon the passive
resistance built up at the installation stage of that tie.
With regard to the soil parameters which should be used in
determining the passive pressure which is available at any
particular stage of excavation, it is considered that the design
should be evaluated for two conditions, firstly using the
immediate or undrained soil parameters and secondly with the
drained soil parameters, as it has been shown that the latter
condition can arise in a very short time period. This approach,
is, therefore, applicable not only to the design of works of a
permanent nature such as underpasses but also for temporary
works where, as in basement construction, the wall is only
exposed during the construction period. Since the drained
parameters approach the ultimate strength of the soil the
factor of safety when using these parameters can be reduced
below that normally employed, and values of I.l to 1.2 are
recommended for consideration.
Design Method
The following design method for multi-tied walls has been
developed by Cementation to incorporate the effects of the
temporary support produced by the passive pressure at intermediate excavation stages.
It involves a procedure which calculates the position and
Design and Construction Considerations
magnitude of a resultant tie at any stage of excavation by
treating the wall as a single tied structure.
The method requires that the following assumptions are
made;(I) The mobilising and resisting soil forces are those
determined using Rankine's earth pressure theory;
(2) At failure there is a unique point of rotation in the
plane of the wall; and
(3) The wall is only of sufficient length to mobilise a factor
of safety of unity' against rotation at any stage of excavation.
The first assumption is made to simplify the calculations.
and is the usual one made when calculating earth pressures
in the design office.
The second assumption, that the point of rotation occurs in
the plane of the wall, enables the following simple procedure
to be used in calculating the additional tie bar forces produced when the passive pressure is "transferred" to the active
side during the next stage of excavation.
Consider the equilibrium conditions of the system shown in
Figure 2 (a) and (b).
From Figure 2 (a) ;
ZH=O is satisfied when;
T,=Pa'-Pp'
ZM=O is satisfied when:
Mp=Ma
(about position of T,)
From Figure 2 (b)
ZH=O is satisfied when;
T,+T2=Po."-P/'
1:M=O is satisfied when:
Mp"=Ma"
(about the centroid ofT,
(c)
TI
T1
TI
and T2)
In considering a resultant tie R, in Figure. 2 (b). acting
at the centroid of T, and T 2.
then:
R,=T, +T2=Pa"-Pp"
Substituting for T 1 from equation (I)
then Pa'-Pp'+T2=Pa"-Pp"
hence T2=Pa"-Pp"-Pa'
+Pp'
which gives the amount of pressure transferred to T 2 when
excavation proceeds to the point for the insertion of T 3'
Figure 2 (c) shows this represented diagramatically.
The remaining problem now is to calculate the position and
magnitude of R,. As T2 is unknown then both the position
and magnitude of R, are unknown. By assuming one the
other may be calculated and the initial assumption checked.
Since the lever arm of R, to the position of factor of safetv
(b)
(0)
(I)
Rl
12
T2
T2
---
Pal
DEPTH OF
F.O.S. = I
Pa
PQ'~Pal
II
}.o.S.= J
Figure 2.
APRIL
1971
THE JOURNAL
OF THE INSTITUTION
Of HIGHWAY
ENGINEERS
17
Anchored Diaphragm Walls in Sand-Some
Design and Construction Considerations
of unity is usually small in comparison to its magnitude it is
necessary that this dimension is calculated to a high degree
of accuracy and the following iteration procedure is recommended to ensure a convergence upon the correct answer.
Figure 3 shows the case where the excavation level has been
reduced to a position for the insertion of the fourth tie.
Considering the equilibrium of the system.
}.;H=0 is satisfied when:
T4=Rn-R
}.;M=0 is satisfied when:
(R.x)-(f 4'y) =0
where y = D - x-I
ORIGINAL GROUND LEVEL.
(2)
Substituting in (2)
f(x) =(R.x)- T4 (D-x-.})
= (R.x)-T4J?+
Substituting in Newton - Raphson's iteration formula,
R.x-T4D+ T4'x+ T4.1
xn+l=Xn
R+T4
In
Rn
D
y
EXCAVATION LEVEL
FOR THE INSERTION
OF TIE T4
T4_
R
Rn
PREVIOUS RESULTANT TIE FORCE.
NEW RESULTANT TIE FORCE.
I-
PREVIOUS RESULTANT TIE FORCE LEVEL.
In
\
NEW RESULTANT TIE FORCE LEVEL
T2.I3, E.I T4
INDIVIDUAL
TIE FORCES.
FIG 3
~ A
-7
6 5 ~ 1 -~ I
IE No I
-
~
~
-
T4.x+ T4.1
-
-
-
-
.-
-
I
where Xn+l is the new estimate of X
and Xn is the previous estimate of X
(This process is continued until the required accuracy is
reached).
This method can now be followed through a typical design
by considering the action of the wall as excavation proceeds.
The first stage of excavation is usually a cantilever having an
exposed height of the order of 2 to 5 metres. The bending
moments in the wall under this condition can be determined
by the usual methods, but it should he noted that the maximum
bending moment occurs below the first tie level and not at
the tie level as is often assumed when designing walls of
this nature.
After the installation of the first tie, the second stage of
excavation proceeds down to the level required for the insertion
of the second tie. Under this condition a single-tied retaining
wall exists for which, as mentioned previously, knowledge of
the interaction of the soil and the wall flexibility is available.
However, when the second tie is installed, very little information is available on the re-distribution of the soil pressures.
In this design method, it is assumed that there is a point of
rotation as in the single-tied wall but this point does not
occur at a tie level but at some intermediate level between the
first and second ties. Since this level cannot readily be deter-
TI E FORCES
Th, H 2 X J 00 PER FT.
TIE
SURFACE lEVEl.
/~/////,.",r
.-
~8?b5~!~I--'
01
- - - -- - -
TIE FORCES
T/~H2)(JOO PER FT.
SURFACE- lEVEl.
TIE No 2
-t----
TI E No 2
-+--
-.-
TIE No 3
-
--
EXCAVATION lEVEL
WALL WITH TWO TIES
FIG 4 (A)
18
THE JOURNAL OF THE INSTITUTION OF HIGHWAY ENGINEERS
WAL L WITH THREE TIES
FIG 4 (B)
APRIL 1971
\\
~Anchored Diaphragm Walls in Sand-Some
,
Design and Construction Considerations
Also shown are the results obtained for analyses carried out
by the generally used methods.
Figure 5 shows the method compared with a full scale experiment and designs for this project submitted by various
engineers,
Field evidence from other tests on full scale walls is
encouraging, but modifications to the method will be built in
if necessary in the form of flexibility coefficients when the
complete results of full scale and model tests, currently being
carried out by Cementation, are available.
mined its position has to be estimated, as oullined previously.
~This procedure may be continued down through any number
of ties.
Comparison with Existing Design Methods
Comparison of designs carried out by the Cementation
method and experimental work indicates that the results
obtained provide a good estimate of the horizontal forces and
Figure 4 shows this method compared with model experiments
carried out by Rowe and Briggs(2) for 2, 3 and 4 tied walls.
TIE FORCES
I
T/~H2 X 100
98765432
T1El'J~~
PER FT
SURFACE LEVEL.
_
TIE No 2
-i------
KEY TO FIG 4
EXPERIMENTAL RESULTS
TSCHEBOTARIOFF'S
METHOD
TERZAGH(S METHOD
BRINCH HANSEN'S METHOD
CEMENTATION'S
METHOD
TIE No 3
-~--
ACTUAL
T
TIE No 4
~------
TIE FORCE
DENSITY
,~
TOTAL
H
HEIGHT RETAINED
EXCAVATION LEVEL
WALL WITH FOUR TIES
FIG 4 (C)
COMPARISON
OF STRUT LOADS
ON RETAINING
WALL.
0'00'
GRAVEL, SAND,
SILT t CLAY
4'
.~~ili~
to'
8-110;<;6'35° W.l. SI
C.0;~.10.
SILT,
::' __
=:~:;;:=r -.- --------------------... ------
--
KEY
G.R.
G.D.
T
WA.
W.B.
-10'0'
21'
1S-1I0;ip.
C-400; &-1 19'
c.n.
CW = 200
A
GOLDER
GOULD
TSCHEBOTARIOff
WILSON 'A'
WILSON 'B'
CEMENTATION Co LTD
ACTUAL
::1=11
=
S2
-30.0'
TILL,
REFERENCE
JOURNAL OF THE SOIL
MECHANICS f.. FOUNDS. DIVISIONAMERICAN SOClEiY OF ENGINEERS
- MAY, IQ70.
NOTES 1) STRUT LENGTH = 12' 0
18'
l=135; 16.38'lt
CoO; 6 = 15°
53
C.O
-40.0'
10'
NOTES
DURING CONSTRUCTION IT WAS .FOUND THAT
PENETRATION BELOW bO' COULD NOT Sf.
ACHIEVED. THE ACTUAL LOAD ON S5 THEREFORE
IS HIGHER AS THE WALL TENDS TO CANTILEVER
OVER S5.
- 500'
S5
b'
-bO'O'
O.
100
200
300
400
STRUT LOAD IN 'KIPS.
APRIL 1971
5000
bOO
700
FIG 5.
THE JOURNAL OF THE INSTITUTION OF HIGHWAY ENGINEERS
19
.Anchored Diaphragm Walls in Sand-Some
It is considered that until a method of design is produced
which takes into account the full interaction of the wall and
the soil flexibilities then empirical methods cif this nature
must be used. The approach described takes account of varying soil strata, wall flexibility and method of excavation, and
should enable the design engineer to make a better assessment
of the wall's behaviour than by assuming a trapezoidal pressure distribution for a continuous wall, for which it was not
originally envisaged,
The main advantages of the new method are listed below:(I) It is a repetitive single-tied wall design with which most
engineers are familiar and should involve no difficulties in
implementing;
(2) It is amenable to varying soil strata which has always been
a problem when implementing the trapezoidal method;
(3) It allows struts or ties to be inserted at levels chosen hy
the engineer to take full advantage of the initial cantilevering
abilities of diaphragm walls which is difficult, if possible at \\11
when using the trapezoidal method;
(4) It allows the wall penetration to be calculated based on a
rotational criteria as well as the direct sumation of horizontal
forces used in the trapezoidal method; and
(5) Although the procedure is simple, it produces results
which comply closely with current experimental data available.
The necessity of close co-ordination between the design,
soils and construction engineers throughout all stages of the
work is again emphasised because, whenever the problem of
foundations is being studied, especially in the field of retaining walls, the design may have to be amended as the work
proceeds. The limited number of boreholes which can be put
down on any site is generally insufficient to provide a complete
picture of the ground strata and tie bar positions and forces
may have to be varied as construction takes place. For this
purpose it is necessary for a quick and rapid design method to
be available. It is noteworthy that Cementation have produced
a computer program which can analyse continuous multi-tied
walls supporting soils of varying characteristics which enable
quick amendments to be made to the design based on the soil
conditions exposed as the wall is being constructed.
2.
WAll
CONSTRUCTION
Plant for Excavation of Diaphragm Walls
The plant used for excavation of diaphragm wall trenches
can be divided into two main groups:(i) First group - reverse circulation plant. The principle of
machines of this type follow the drilling technique in which
the rotary drilling bit loosens the ground, which is mixed with
bentonite suspension and brought up by circulation of the fluid
through a hollow drilling rod (or kelly). The bentonite suspension plays a double purpose of stabilising the excavation and
conveying the soil to the surface.
(ii) The second group uses tools which direcUy excavate the
soil. The bentonite suspension is only employed to provide the
support for the sides of the trench. There are many types of
plant in this group:(a) Mechanical diggers - either back or forward acting, can
be used successfully for shallow depth (2.5-3 metres).
(b) Bucket excavators of special construction (E.L.S.E.)
(c) Machines using special trenching grabs.
The la'st';type is most interesting and in recent years economica!" ifiil 'efficient machines have been produced using grabs.
The trenching grab is the width of the trench but its length
is seve?al times greater. The usual length is about 2 metres.
Originally, trenching grabs were exclusively rope operated
and this type is still widely used, but to improve efficiency,
power closing grabs have now been developed. The power can
be hydraulic (ram operated mechanism) or electric (motors
on the grab). The superiority of power in closing grabs consists of speedier operation and the fact that the full weight
of the grab effectively presses its jaw into the bottom of the
trench during closing. In the rope operated method the weight
is partly used to close the grab.
10
THE JOURNAL Of THE INSTITUTION_Of_HIGHWAY ENGINEERS
/
~',~.
~-----~.~
Design and Construction Considerations
l
,
,
'.
!...
:
I.
Figure 6
Further improvement in design consists of providing a kelly
to which the grab is fixed. The kelly is guided above the
ground and the purpose of the arrangement is:(i) to position and stabilize the grab above the trench in the
minimum of time;
(ii) to guide the grab during lowering in a true vertical line;
and
(iii) to provide additional weight to the grab.
Kelly-guided grabs are usually erected as an attachment to
standard cranes forming an efficient unit, Figure 6 shows the
Cementation Trencha Grab which can reach a very high out.
put - 10 or even 15 sq.m per hr.
Trench Excavation
"
(a) Bentonite Suspension
The first recorded use of bentonite suspension to stabilize
the side of a trench was for a wide excavation of a cut off wall
with plastic fill in America in 1950. Later, about 1952-53, a
narrow type of concrete diaphragm was executed in Italy.
By 1954 a "slot" type excavation was an established procedure.
Bentonite is a special kind of clay (sodium form of Montmorillonite) and the properties of bentonite suspension were
first studied about 1926 by Freudlich and later by Lorenz and
Veder. These physical properties, which make bentonite useful
in stabilising the sides of a trench during construction, may be
summarised as follows:I
(i)
Dispersion
Bentonite, like other clays, is essentially insoluble in water,
but when mixed with water disperses under hydration much
more easily than other clays. The dispersed particles are elongated, disc-like, about 2-3 microns thick and up to 300 microns
in length. Even a low c0ncentration of bentonite of a few
per cent (by weight) readily forms a colloidial suspension,
which in many respects behaves like a solution.
(ii) Thixotropy
The bentonite suspension exhibits thixotropic properties,
i.e. it gels when undisturbed but becomes fluid when agitated
by mechanical stirring. The most popular explanation of the
APRIL 1971
Anchored Diaphragm Walls in Sand-Some
thixotropy
of bentonite is based on a theory that the clay
particles have negative elcctrical charges on their planer sur.
faces and positivc charges on the edges. In a state of gel the
particles are orientatcd by electrical forces-a
negative surface
to positive edge-and
form a "lattice structure",
which pro'
duces the effect of a gel. When the suspension is agitated, the
bonding forces are broken, the particles are orientated
at
random and thc suspension becomes fluid. Left undisturbed,
the "structure" is automatically
rebuilt into a gel form.
(Hi)
J
)
Capacity to fonn a filter cake.
When placed
over a filtering
medium
the bentonite
smpension loses part of its water into the permeable material
v/hilst the solid constituents form a "cake" of clay particles on
the surface of the medium. This filter cake, of few millimetres
thickness,
provides
a fairly resistant
skin, which can be
practically impervious.
When
a bentonite
suspension
is introduced
into an
excavation where the strata are pervious, it will penetrate the
soils. The depth of penetration
depends on the excess hydrostatic pressure, the p::rmeability of the strata and the viscosity
of the fluid. When equilibrium
is reached, the fluid forms a
gel in [he trench and in the penetrated
zone. Under excess
pressure a filter cake is formed on the sides of the excavation.
As the digging tool enters the cxcavation it turns the gel into
a fluid, but its disturbing action does not extend to the gel
entrapped
in the penetrated
zone or break down the cake
membrane on the sides.
This virtually impervious membrane allows the hydrostatic
pressure of the suspension to act on the sides of the excavation,
without raising the pore water pressure within the mass of the
soil. This is one of the basic principles of the stabilizing action.
(b) Stability
The question of stability and equilibrium
of forces under
bentonite
is often discussed and the names of Schneebeli,
Morgenstern(4). Nash(S), Veder<1) and Elson(9) are well known.
The subject of the stability created by bentonite was also the
topic of one of the Speciality Sessions of the Seventh International
Conference
on Soil Mechanics
and Foundation
Engineering
in Mexico 1969. At this session, the reporter,
J. Florentin(lO>, said 'The record of some three million square
metres of walling already completed
tends to show that a
method of construction has been developed before a theory of
stability. co.ordinated
and acceptable
to everybody,
can be
established."
He added encouragingly
"Should we not be
reminded
that aeroplanes
were flying before aerodynamics
existed. "
The problem consists of expressing theoretically the state of
equilibrium which must exist in practical cases, between earth
pressure and the support offered by a bentonite suspension. Tn
many cases it is not possible to balance the forces on the basis
of the simple hydrostatic pressure of the suspension and earth
pressure based on existing classical theories; hence the ten.
dency of researchers to look for some secondary factors, which
can contribute
to the stability. Such factors often discussed
are:(a) The shearing resistance of bentonite in gel form.
(b) An arching action of the soil in relation to the usually
limited dimensions of an excavated panel.
(c) The resistance of the bentonite cake, which can act as
reinforcement
in both vertical and horizontal directions to the
sides of the excavation.
(d) An increase in the shearing resistance of the zone of soil
which the bentonite gel permeated beyond the cake.
(e) Electro osmotic forces.
In practice, Elson(9) estimates that the main stabilizing forct:
is the hydrostatic
pressure of the suspension, which accounts
for 75 to 90 per cent of the stabilizing force. It is a matter of
experience that, if any minor collapse of the trench does occur,
this usually involves a zone of soil at shallow depth, for
example, just beneath the concrete guide walls. It may well be,
therefore, that classical theory overestimates
the soil pressures
in the lower part of a narrow trench.
APRIL
1971
Design and Construction Considerations
Since no precise formulae exist at present for the calculation
of the stability of an excavation under bentonite suspension,
it is up to the sp~cialist engineer to assess the conditions and
use his own judgment, based on site experience.
The following procedure is proposed in the analysis of the
problem. It is hoped that it will help the engineer in his
appreciation,
showing what are the essential assumptions
and
what is left as intelligent speculation.
(i) First the possible passive resistance of the bentonite suspension must be examined since this is the basic force which
props the sides of the excavation. Neglecting the shearing resistance of the bentonite suspension, the basic stabilizing force
can be expressed
as a simple hydrostatic
pressure
which
depends on the specific gravity (S.O.) of the suspension. Tho:
5.0. of a freshly mixed suspension of low concentration
is
only slightly higher than 1.0 but, when introduced
into the
trench, it soons entraps grains of soil and increases in density.
Experience shows that, in average sandy conditions,
the 8.0.
can rise to about 1,2 when grab excavation is used. (It is less
if a reverse circulation
system is used.) Table 1 illustrates
TABLE
BENTONITE
I
SPECIFIC GRAVITY
RANGE
Specific
Gravity
Range
General
Ground
Conditions
Normal
Bentonite
Mix (%)
A
Made ground
Cobbles, Clay
4.5
1.05-1.19
B
Sand & Gravel
7.5
1.10-1.24
C
Shale, Gravel,
Sand, Sandstone
9
1.15-1.20
D
Cobbles;n hard
Clay
4.5
1.05-1.10
E
Sand/silt
6
1.15
Contract
lypical S.O. values for bentonite mixes.
Next it is necessary to check the level of bentonite which
can be maintained
at all times during the trench excavation
and concrete placing stages. It is necessary to examine the
strata for possible loss of bentonite, which the supply could
not maintain without a lowering of its level in the trench. Very
open strata, of permeability
(Kw) more than 5cm/sec,
can
practically prevent the level being maintained
at the required
height. Similarly, cavities or unused drains can cause a sudden
lowering of bentonite level.
The level of bentonite in relation to the ground water table
is also important
since the filter cake can only be formed if
there is an excess of head in relation to ground water level.
The practical lower limit is about 1.5 metres.
As a result of the above study, a pressure line of basic
bentonite support can be drawn for both the minimum
and
maximum anticipated density, bearing in mind that the density
of the suspension will increase from the lower to the upper
limits of this range, as the excavation proceeds.
(ii) The second analysis refers to the expected active earth
pressure. Employing
the classical two dimensional
theory of
earth pressure, soil parameters
such as 4> and unit weight
must be carefully established together with the water level and
its variations.
In addition surcharge loadings from adjacent
foundations must be assessed when present in order to facilitate
the calculation of the active pressure in terms of KA. A pressure
line can then be drawn to the same scale as the pressure of the
bentonite.
(Hi)
A first comparison of the bentonite hydrostatic
pressure
and the active pressure lines should provide a general appreciation of stability.
THE JOURNAL OF THE INSTITUTION OF HIGHWAY ENGINEERS
21
Anchored Diaphragm Walls in Sand-Some
Design and Construction Considerations
If the line of bentonite pressure is at or above the line of
active earth pressure, there is obviously
nothing to worry
about. If the deficiency of bentonite pressure is more than 25
per cent say, which is more than can be expected from the
secondary
factors, a further study or test is required. The
recommended
figure of 25 per cent is arbitrary and open to
discussion. If the deficiency is less than 25 per cent a study of
the influence of secondary factors is necessary.
The secondary factors have already been listed and it is now
relevant to comment on their quantitative
effects:(a) ShfW"ing re.-ooa11tt of beutonite in gel fonn - Elson is
of the opinion that this will not exceed 5 per cent of the
stabilizing force. However, since the excavating tool disturbs
the gel and can reduce its shear strength to negligible proporions, this factor can be omitted.
(b) Arclting action of the soil in relation to the limited
dimensions of a panel. This aspect can be very important and
the analysis of a three dimensional wedge or longitudinal arch,
as suggested by Schneebeli (1964)(6) is recommended.
(c) The Tcsistance of tire bentoo.ire cake. This is an unknown
quantity and difficult to introduce jnto the calculation.
It is
suggested that its influence be ignored.
(d) An increase in shearing resistance of the zone into which
tlte bentonite penetrated.
This aspect is treated in detail by
Elson. He estimates that, in practice, it accounts for 10 to 25
per cent of the stabilising force when excavating in sands.
(e) ElectnMxsmotic
forces. These forces are rather indefinite,
but they have been analysed recently by Wielicka(8} (1967) and
proved to be insignificant.
In most cases the introduction
of approximate
values for the
above factors allow a balance to be established between the
active and passive forces. In general, if the water level is some
1.5-2.0 metres below the ground level and the strata is not so
pervious as to preclude the possibility
of maintaining
the
suspension level, the excavation can be stabi1ised with bentonite. Certain difficulties can, however, occur with new hydraulic
filts. If properly used the method can control running sands and
silts.
Although a record of collapses does not exist, it is significant
that most collapses occur in upper strata, which does not tie
in with classical theory. Perhaps the lower strata possesses a
better shearing resistance than is usually accepted, as suggested
earlier, or the active earth pressure tends to be limited at depth.
Settlement of Adjacent Ground
The excavation of the soil from the trench under bentonite
reduces the initial existing earth pressure at rest to the ben
tonite pressure, and consequently
some movement
can be
expected.
If the support of the bentonite suspension approximates
to
the active pressure, then the active pressure in the ground will
virtually be mobilised. Settlement of the adjacent ground will
then depend mainly on the state of compaction of the soils. For
compact sand, settlement could be almost zero up to 1/1000 of
the supported height whereas for loose sand this fraction could
rise to. say. 1/200. In practice however, the support of bentonite
is above the theoretical
active pressure of the soil and the
rational approach would be to evaluate by how much it exceeds
the active pressure and then to consider the strain created by
the stress mobilised in the soil. Using a small scale model in the
laboratory,
Elson measured the settlement ( fJ. s) and related it
to the co-efficient of safety. For factor of safety 1.2, his
graph shows a settlement of about 1/1000 of the supported
height (H) and, for 1.05 ~s is less than H/500. The settlement
will diminish away from the wall and should not extend beyond
the formation of the "active wedge".
Combining practical experience with present limited theoretical knowledge, special precautions should be considered where
adjacent
buildings or structures
are particularly
sensitive to
settlement and the foundation soil is loose. In such cases it is
advisable to reduce the length of panels to a minimum of. say,
2 metres. In this way precautions taken by old trench diggers
are followed and the theoretical factor of safety against mobj]11
THe JOURNAL OF THe INSTITUTIONOF HIGHW"Y eNGINeeRS
ising the active soil wedge is increased by invoking the support
offered at the ends of the panel due to arching within the soil.
In the case of very severe conditions of loose strata and very
heavy superimposed
loads on adjacent ground. consideration
can be given to chemical stabilisation
before the trench is
opened.
In most cases where the soil is moderately
compact and
where a standard length of panel of about 5 metres is adopted,
the expected settlement will be negligible.
It may be concluded that the digging of a narrow trench,
using conventional methods, to build a wall to protect a future
excavation, is an established and successful method often used
in the immediate
vicinity of nearby buildings. Excavation
under bentonite to install the wall offers much better conditions
since it supplies instant support for the excavation, prevents
influx of soil into the excavation and does not require pumping
associated with the lowering of a ground water table. There are
numerous examples of bentonite walls installed successfully in
the proximity of tall buildings, even in relatively soft grounds.
Concrete for load bearing diaphragm walls
General
Requiremellts
The requirement
for finished concrete in the diaphragm wall
does not vary substantially
from concrete in other reinforced
concrete structures.
The concrete for diaphragm walls is poured through bentonite by means of a tremie pipe and gradually, under gravity
forces, displaces the bentonite fluid from the excavation. No
mechanical means of compaction are used and for a successful
concreting operation, it is imperative to take into consideration
placing conditions at the stage of the mix design. The requirements for a mix, which can successfully
be placed under
bentonite (or water). can be summarised as follows:
(i) The consistency should be f10wable to allow for gradual and
complete filling of the excavation under gravity forces. The
S.G. of the concrete is 2.3 approximately
while the S.G. of
bentonite suspension varies from 1 to 1.3 depending on the
degree of contamination.
The more flow the concrete has the easier the tremie operation. There are, however, limits - too liquid a concrete may
not be cohesive enough, or may show loss of strength.
(ii) The mix must be cohesive and must not segregate or
bleed.
,
(iii) Setting time of the mix must be long enough to permit
the operation of concreting to be completed without adverse
effects on quantities already delivered.
(b) Mix da;ign
The mix designer has to ensure that the above requirements
are satisfied as far as possible, bearing in mind the final requirement of adequate strength, durability and impermeability.
Badly designed mixes which are too stiff or not cohesive
can cause serious difficulties such as blocking the pipe, insufficient filling of ends and corners of the panel. segregation or
mixing with bentonite.
The following are practical recommendations:-
1. Grading of the aggregate
In order to make a "f1owable" consistency, the water has to
be "trapped"
within the aggregate. It has been found from
experience that particles, which effectively oppose movement of
water within the mix are particles below British Sieve Size
No. 25 and these particles have to be in sufficient quantity.
Normally, 20 to 30 per cent of this size makes good concrete.
. In order to reduce the tendency for segregation, it is advisable to reduce the maximum size of aggregate to 19mm. The
shape of the grading curve should show evenly graded aggregate. Gap graded concrete is prone to segregation, but a certain
flattening of the curve between sieve No. 14 and 5mm can
be advantageous.
Gradings which have been successfully ~mployed are illustrated in Figure 7.
APRIL 1971
Anchored Diaphragm Walls in Sand-Some
VARIOUS AGGREGATE CURVES.
AS USED FOR CONCRETE PLACED UNDER
ZONE
C.
BENTONITE.
-- - -
./
LIMIT
Design and Construction Considerations
,/
Y
/'
./
./
ZON
...
A (SEE ROAD NOTE No")
.' -
....
<'-<
.....
.....
'"
N
2:
Cr-
..t-
.~~.
~,:ft
'",
~
2.
&.000
7,500
3.
7.000
b,5oo
..
-
cpoo
5~0
~
~
::;.
~
~.500
R~QD
~.OOO
~poo
APRIL 1971
.
7 DM~
MiN. CONT<NT Of CEMENT:
~LUMP: 7~
51M CUIWE Nos I ~2.
CUBE TE5T RESULTS.
Water quantity -
plasticisers
The water quantity should be adequate to produce a consistencyof 150-200 mm slump. To reduce the water requirements
it is advisable to use plasticisers of a reputable type to make
the mix more cohesive and permit a reduction of water content
by 10 to 20 per cent. Reduction in water content not only
increases the cube strength but also has a pronounced antibleed action. Also, it increases, albeit slightly, the specific
gravity of the concrete, which helps to displace bentonite
during placing and increases the resistance of concrete to
erosion. On average, the water/cement ratio can be maintained
at slightly above 0.5.
(c)
FIG 8.
.k
4. Retarders
The time of setting has to be checked against timing of the
operation. Concrete setting too quickly (especially at high tern.
peratures) can be very difficult to tremie. In suct'\ cases, retarders are advisable. It should be noted that a slight excess 01
water is less harmful than an insufficient quantity, which
would produce stiff, non-ftowable concrete. Similarly, an excess
of fines is less harmful than a stony mix. However, none of the
above recommendations should be exaggerated.
Examples of composition and cube test results are included
in Figure 8 and it should be noted that excellent results have
been obtained with very high slump concrete.
5.000
2.500
Cement quantity
Because of the high quantity of fines and water, the cement
content is high to ensure the required strength. In addition the
cement particles are required to combine with the fines of the
aggregate and water to produce the desired cohesion and
flowability. In practice, the recommended minimum limit fO!
a (21 N/mm') 3000 p.s.i. concrete is 392 Kg/m" per cubic yd.
of concrete (however leaner mixes are also used).
The chosen cement quantity should also contain a factor of
safety to cover the scatter of cube test results for flowable
concrete and for local partial segregation, which can occur in
spite of the best supervision.
2& DAYS
"bO LOS/CU. YD.
Tromie Concreting,
The operation of concreting is simple but requires great care.
I( is important to check the concrete by slump tests and general
appearance. This latter aspect should not be underemphasised
since the human eye can be easily trained to detect bleeding,
segregation and non-acceptable consistency.
Prior to concreting, the boltom of the trench should be
cleaned of debris and bentonite suspension, which is contamiTHE JOURNAL OF THE INSTITUTION OF HIGHWAY ENGINEERS
23
Anchored Diaphragm Walls in Sand-Some
nated beyond acceptable limits. The next step is the placing ot
stop ends true to position and verticality, followed by the
placing of the reinforcing cage and finally by the tremie pipe.
Tremie pipes used for concreting are lOin. diameter steel
pipes, and the required length is obtained by joining separate
lengths of pipe. There is no standard length of pipe between
joints, but to allow for simple adjustment of the tremie length
during concreting, 2 metre lengths are recommended. The joints
of the tr~mie must he watertight, easily disconnected and without projecting flanges, since these could foul the reinforcing
cage. Experience shows that threaded pipe joints, carefullv
handled, are most practical.
The tremie pipe is placed in the centre of the panel, although
two tremie pipes are sometimes placed in long panels. Thr;:
bottom of the tremie rests firmly on the ground, and the funnel
hopper is placed at the upper end. After assembly of the
tremie a "plug" is placed in the tremie floating on the
bentonite. The purpose of this plug is to separate the initial
batch of concrete from the bentonite, which is in the pipe. As
concrete is poured into the tremie, the plug travels down under
the weight of concrete, until it reaches the bottom.
The tremie pipe is then lifted slowly from the bottom allowing the concrete to push the plug out. From this moment the
end of the tremie must always be submerged in concrete and it
is therefore important to check the level of concrete near the
tremie and at the end of the panel regularly, after every delivery. A sounding weight of S.G. = 2, is recommended for thi~
work.
During concreting. the top surface of the concrete will slope
from a high point at the tremie to a low point at the ends of
the panel. This slope indicates that the concrete is travelling
upwards from the bottom of the trernie pipe in greater quantity near the pipe than at the ends. This must be associated
with a horizontal movement on the concrete surface from
the centre to the ends of the panels.
The more fluid the concrete and greater the value of submerged length in relation to the length of the panel, the less
movement can be expected. For very short panels and a long
submerged length, the filling of the trench will consist of a
vertical movement without a horizontal component. This
horizontal movement can influence the concreting operation
in two ways:(i) the top concrete is gradually exchanged for fresh concrete
and the time at which the initial set occurs is not as critical as
in very short panels or piles; and
,
(ii) the impurities in the bentonite are gradually moved forward to the ends of the panel and this fact has to be considered
when cut ofllevel is reached.
Bond Stress
Prior to concreting, the steel is immersed in the bentonite
suspension. The concrete rises, gradually displacing the suspension. The suspension cannot build a filter cake on the surface
of the steel, as it is not pervious. It can adhere to the bars only
by its cohesion which, for the concentration employed, would
be approximately 2000 dynesfcm2 or 215 Nfm2. Rising concrete, due to its granular composition and its inherent friction,
exercises a sort of sweeping action which removes the bentonite suspension from the bar. On removal of stop end pipes
placed as shuttering at the end of the panels, it can be observed
that this sweeping action is efficient. If left longer than a few
hours, it is almost impossible to remove the pipes because
concrete adheres to the steel, which was submerged in bentonite. Experiments carried out and described in CIRTA Report
1967, have shown that the bond stress, at no slip condition,
of round mild steel bars was not materially affected, but for
deformed bars, where employed, the bond stress is reduced. The
probable explanation of the above is that deformed ba~
prevent efficient sweeping action and bentonite suspension is
trapped under the deformations.
As a result of this report no adjustments are made for safe
bond stress of plain bars but a reduction of 10-20 per cent is
applicable to deformed bars.
24
THE JOURNAL
OF THE INSTITUTION:OF
HIGHWAY
ENGINEERS
1
Design und Construction Considerations
!
3 ANCHOR DESIGN
Site Investigation
Of paramount importance is the provJSlon of site investigation data which will facilitate anchor design and choice of
anchor construction technique. The basic information required
is illustrated in Table 2.
I,
TABLE 2
Item
Data Required
Borehole
General Soil Profile
Ground Water level
Undisturbed
Sample
Shear Strengths (r/>, Cu, c' &.p ')
Density
Consolidation and Compressibility
Indices
Distu rbed
Sample
Mechanical Analysis
Chemical Analysis
In-situ
Test
Standard Penetration
or Dutch Cone Readings
Vane Test Results
Construction
Proximity of operations such as
piling, blasting orfreezing
In sands the friction angle (</» combined with the effective
overburden pressure enables the capacity of the anchor to be
calculated since the resistance to pull-out of the anchor
depends on the ground restraint which can be mobilised
adjacent to the grout injection zone.
Grading samples are invaluable since they enable the permeability and therefore the groutability of the soil to be
assessed, and in addition when the samples are used in can.
junction with standard penetration tests to estimate relative
density, then </> values can be determined if these are not
already available.
Chemical analyses of the soil and groundwater are important
since sulphate content and pH for example can dictate the
type of cement grout and degree of corrosion protection.
Anchor Location .
Since the waling level and spacing of the anchors is deter.
mined in the wall design, the location of the top anchor is fixed
and only the inclination and length of the anchor remain to be
calculated.
Anchor inclination is kept small and ideally should be less
than 20° to the horizontal. In many cases however this is not
possible due to the proximity of adjacent foundations, and
values of 200 .450 are common.
MINIMUM
DEPTH
= 15'-20'
I
/
/
/
/
fiXED
~NCHOR
ZONE.
fs~
Figure 9
APRIL 1971
'.
I'
Anchored Diaphragm Walls in Sand-Some
With regard to overall length, the fixed anchor must be
embedded (a) deep enough to avoid the localised passive failure
of the soil associated with the failure condition for shallow
dcadmcn; and
(b) far enough away from the wall to ensure against a slip
failure beneath the toe of the wall and beyond the fixed anchor
zone, at a lower factor of safety than the design specification
allows.
A minimum
depth of 5-6 metres is normally considered
sufficient to guarantee a deep seated failure condition at pullout, and, for initial guide purposes only, the "free" anchorage
length may be estimated
with the help of the construction
diagram shown in Figure 9.
Overall Stability
As a second step the stability of the whole system must be
checked to ascertain whether the chosen anchor lengths are
sufficient or not. Where the waling loads on the wall have been
designed according
to the principles outlined earlier it is
assumed that the anchor prestress introduced will prevent sli~
planes occuring between the wall and the fixed anchor zone. In
other words it is assumed that the prestressing of the anchors
introduces a new state of stress in the retained soil mass where
the normal stresses and consequently
the shear strengths become large enough to prevent the mobilisation
of sliding
surfaces ahead of the fixed anchor zone. The sliding surfaces
which are still possible will therefore pass beyond the fixed
anchor zone. As an additional safety precaution the midpoints
and not the ends of the fixed anchors are usually arranged
along the sliding surface with the required safety factor,
according to practice in Europe. It is noteworthy, however, that
in the absence of detailed information
on fixed anchor/soil
interaction,
the authors consider that the fixed anchor zon;)
should be completely beyond the estimated slip plane.
The shape of the sliding surface which will occur for
systems with only one row of anchors is known through the
work of Kranz (1953)03), Jelinek and Ostermeyer (1966)(14) and
Ranke and Ostermeyer
(1968)(15) and the procedure recommended for consideration
is a modified Kranz method sug.
gested by Locher in 1969 (Figure to).
:
~/
!
!
/
Design and Construction Considerations
weight G and the forces Et and Rn are in equilibrium.
If this
i:i not the case then <t>nhas to be altered and when equilibrium
the factor of safety is defined as F = tan 4> where
tan 4>n
4> is the actual angle of internal friction. This definition
corresponds
with the concept of partial safety factors as pro.
posed by the late Professor Brinch Hansen. It is considered
that the main attraction of this method is its simplicity, and
although the forces acting are assumed to be concurrent
it is
considered that the value of F is a safe estimate since the
stabilising
passive resistance available from the embedded
depth of soil within the excavation, is ignored in the calculation.
For systems with several rows of anchors the shape of the
sliding surface is not known from experiments and the stability
is evaluated using the circle or logarithmic
spiral method. A
logarithmic
spiral has the property that the radius from the
spiral centre to any point on the curve, forms a constant angle
.;, with the normal line to the curve. If a nominal friction
i:i achieved
angle of the soil 4>n is employed
where tan 4>n~ ta~ cp, then
the line of action of the resulting forces on each part of the
sliding surface will pass through the spiral centre. None of
the forces along the sliding line will therefore create a moment
around this point, and they can therefore be neglected, when
considering the equilibrium of moments around the point.
The safcty factor F is correct, when the moments of the
remaining weights and forces on the sliding body total zero.
Figure 11 shows the principle, and again, by ignoring the
passive resistance of the soil beneath the excavation when the
moments produced by Gt and Gs balance, a conservative value
is obtained of F equals tan cp/'tan cp'n.
In both the stability analyses described the basic assumption
is made that anchor prestress increases the shear strength of
the sand sufficiently to displace the potential
failure plane
beyond the fixed anchor. Care should therefore be taken not
/
/
/
i
i
i
I
i
i
.......
~
-
--
Rn
......
MGs
SPIRAL
F
=
~ n:
=1
MGt
tg (>
t9 ~n
F
=
tg ;
tg ; n
Figure 11. Stability analysis-spiraL-shaped
Figure 10. Stability of a wall with
modified Kranz Method.
aIle
row of anchors:
The earth pressure E, on the vertical cut through the midpoint of the fixed anchor is calculated with a nominal friction
angle 4>n. and the resultant force Rn on the inclined plane of the
sliding wedge must form the same angle 4>n with the normal
to the sliding plane. 4>n has been correctly assumed if the
APRil
1971
sliding surfaces.
to apply these methods outside the range of cohesionless soils.
[n stiff cohesive soils for example it is clear that anchor prestress will only increase the soil shear strength gradually
as
consolidation
occurs. Consequently, in this situation, a conventional analysis of the overall stability should be carried out,
neglecting the presence of the soil anchors, and then the fixed
anchor must be located some distance beyond the potential
slip zone to ensure that excessive pressures are not transmitte:l
across this zone, which might lead to premature failure.
THE JOURNAL
OF THE INSTITUTION
OF HIGHWAY
ENGINEERS
2S
Anchored Diaphragm Walls in Sand-Some
Design and Construction Considerations
load carrying capacity
In fine to medium sized sand where the permeability
(K W)
ranges from 10-2 to 10--4 cm/sec, the fixed anchor formed
consists of a smooth grout cylinder since the sand does nOl
allow permeation
of the dilute cement grout (Figure 12).
Where anchors are formed in fine cohesionless
soil using
cement grout, safe working loads are usually limited to 40 tons.
Factors of Safety
Having established the ultimate load holding capacity of the
anchor using either equation 3 or 4 it is necessary to apply a
factor of safety to guarantee the performance
of the individual
anchor. In multi-anchor
systems where progressive
failure
must be prevented, the minimum factor of safety (Sf) normally
employed is 1.6. Since the local soil properties are not normally
known with the degree of accuracy associated with the steel
components of the cable and top anchorage, a value of 2 is
common for fixed anchor design in cohesionless soil both for
temporary and permanent works.
In order to check and possibly optimise the fixed anchor
design at the beginning oi the contract a minimum of three
test anchors pulled to failure is recommended
where the fixed
anchor length is varied and the cable is designed in each ca~e
to ensure that failure occurs at the fixed anchorlsoil interface.
With regard to overall stability a factor of saiety F = 1.5
is customary, but as in all designs the choice is based on how
accurately th~ relevant characteristics
are known, whether the
system is temporary
or permanent
and the consequences
if
failure occurs.
4
ANCHOR CONSTRUCTION
ConslructiDn
Figure 12
For this type of anchor equation 3 is commonly used by
specialist contractors,
to estimate the ultimate load carrymg
capacity,
T, = L. n' tan cf;
(3)
(metres) 13-]6.5 tim
where L is the fixed anchor length (metres n' = 13-16.5 TIm
and cf; is the angle of internal friction. In equation 3, n' automatically takes account of the depth of overburden above the
fixed anchor h = 6.1-9.2m fixed anchor diameter. D
180200mm and the range of fixed anchor lengths L = 0.9-3.7m
over which the rule has been tested.
In general however, practising engineers require an empirical
rule which relates anchor pull.out capacity with anchor dimensions and soil parameters.
Equation 4 for vertical anchors is
recommended
for consideration.
=
Tf
= Ay
(h-i-~)
1tDLtanq.+B
Bh~
(D2-d2)
(4)
+ B r h 4~ (D2-d2)
(side resistance)
+
(end resistance)
where A = ratio of the contact pressure at the fixed anchor
soil interface to the effective pressure of the overburden.
B = bearing capacity factor.
'&
I
= unit weight of soil overburden
(submerged unit weight
beneath the water table).
h = depth of overburden to top of fixed anchor.
L = length of fixed anchor.
D = effective diameter of fixed anchor.
d = effective diameter of grout shaft or column.
A normally lies within the range 1 - 2 but. the actual value
depends to a great extent on the anchor installation procedure
i.e. drilling method and grout injection pressure. The bearing
capacity factor B depends on the angle of shearing resistance
of the soil and the ratio hiD. It is noteworthy
that in compact
fine to medium sand (q. = 35°) values of 1.4 and 31 for A.
and B. respectively have been measured where rotary percussive drilling techniques
have been employed
with grout
injection pressures of 350 KNlm' to give a ratio LID = 27.
26
THE JOURNAL
OF THE JNSTlT1.hION
OF HIGHWAY
ENGINEERS
Stage
The method
which is employed
for anchorages
in sand
entails a number oi working operations as follows:(I.) A casing, 50-150 mm nominal
diameter,
is driven
through the wall and the retained soil mass to the desired
depth,
using
rotary,
rotary-percussive
or
vibrodriving
techniques.
Anchor hole formation
is aided by various flushing techniques. In sands and gravels, for example, water flushing
widens and cleans the hole and ensures a better bond at the
grout-soil interface.
(2.) The cable, which consists of high tensile strands, wires
or bar is homed, the length oi cable above the fixed anchor
being decoupled from the ground by some form of sheathing.
(3). Grout, consisting of neat cement and water, is injected
into the hole under pressure as the casing is withdrawn over
the fixed anchor length. The hole is then topped up with grout
and allowed to set following complete withdrawal of the casing.
Grout Wlc ratios ranging from 0.4 to 0.65 are recommended
and the injection pressures may vary irom 30 to 1000 KN/m2•
Care should be taken not to exceed the theoretical overburden pressure since this could cause fissuring in the ground
and possibly lead to ground heave at the surface as well as
possible damage to existing anchors. During the grouting stage
therefore,
a careful note of injection pressure is required
together with grout consumption.
Where the ground is variable high alumina cement is often
employed since it enables the anchor to be tensioned within
24 hours. Consequently, if the ground conditions have deteriorated ]ocally without being observed, the tensioning stage will
indicate a reduced capacity, and remedial measures can be
taken immediately.
(4.) Within six hours of grouting, the grout column filling
the hole is flushed back using air and water, to within 1.5
metres, say, of the top of the fixed anchor.
(5.) When the fixed anchor has hardened (minimum crushing
strength of 28 N/mm2 is normally specified), the cable is posttensioned to the desired load.
Thus the anchorage is based on grout injection and consists
basically of a cable which is bonded into a grouted zone of
alluvium (the fixed anchorage). The rest of the cable is encased
in a protective sheath to prevent the cable from coming into
contact with the surrounding
ground and also to provide a
safeguard against corrosion.
APRil
1971
Anchored Diaphragm Walls in Sand-Some
Design and Construction Considerations
Post Tensioning
The post-tensioning
operation pre-tests the anchor, thus ensur.
ing its safety. To establish a measured factor of safety against
withdrawal of the anchor it is necessary to apply a temporary
test loading on site. However. the allowable test load (Tt) is
limited by the elastic limit of the steel cable, and the maximum
recommended
test load is equal to 80 per cent of the breakinil
load (fb). Thus, for a cable working at 62.5 per cent Tb the
maximum measured safety factor which can be provided i~
Sm = Tt{f w = 1.28, where T w is the working load.
Every anchor should be tested to 80 per cent Tb and representative anchors (I in 10 say) should be constructed
with
extra cable where Tw = 50 per cent Tb to give a measured
Sm = 1.6.
,
In fine to medium sized sand fixed anchor displacement
during initial tensioning is fairly common and this should not
be associated with failure. since some relative displacement
as the grout/sand interface may be necessary to mobiIise load,
(Figure 13). In these circumstances
the load carrying capacity
of the anchor is established from a second tensioning cycle.
The fixed anchor movement should then be simply due to
small elastic deformations
provided that the working load is
not greater than 80 per cent of the maximum test load.
It should be emphasised that these test loads are only applied'
for short periods but experience has shown that the decrease in
anchor carrying capacity under long term loading is relatively
modest for most cohesionless soils i.e. loss of prestress due to
fixed anchor displacement
is not greater than 5 per cent.
Figure 14.
under factory controlled conditions. The fixed anchor length
of the cable is then stripped and degreased before casting into
a corrugated plastic tube using a high strength synthetic resin.
This fully protected restressable cable is homed and grouted
in the normal way and after stressing the top anchorage
can
be enclosed by a steel or rigid plastic cover filled with grease
or bitumen.
Corrosion Protection
Full scale sustained load tests have been carried out on resin
bonded strand anchors of this type (Figure 15) and the results
obtained from a test anchor prestressed to 220 tons (70 per cent
U.T.S.) are illustrated in Figure 16. Creep of the lower end of
the fixed anchor amounted to 0.09 mm which occurred within
25 days whilst the movement at the jack amounted to 0.9 mm
after 30 days. This latter creep represents a loss of prestress in
the laboratory
system of less than 5 per cent due to cabb
relaxation and partial debonding in the fixed anchors. In practice, where the "free" or elastic length is commonly
30 ft..
the loss of prestress would be I per cent.
Where ground conditions
are not hostile and the working
life is less than two years, a greased tape decoupling sheath
over the elastic length is normally specified with the normal
grouting procedure which gives a cement grout cover over the
fixed anchor. On completion of the stressing stage the top or
movable andlorage
and the protruding
cable may be painted
with a removable plastic coating such as "stripceal"
(Figure
14).
For permanent
anchors individual strands making up the
cable can be greased and sheathed with extruded polypropylene
5
I
I
I
ESTIMATEDElmN'''N
40
..J
~
::
30
Q
:t_
too",
~z
o
g~
20
OF CABLE
DESIGN DETAilS.
DEPTH OF ANCHORAGE
30 FT
lENGTH OF FIXED ANCHOR
12 FT
lENGTH OF COLUMN
0
DIA. OF CASING
4 in
CABLE No OF VZ"DIA, STRANDS
12
AVERAGE INJECTION PRESSUP.E
75 Ibfin 2
WATER/CEMENT P.ATIO OF GP.OUT
0.64
QUANTITY OF CE MENT
4.5 cwt
GP.OUND CONDITIONS: COMPACT FINE/MED, SAND
WATER TABLE IS 8'-6"
BELOW SURFACE
UJ
u
z
/,
~
in
UJ
..:;
10
o
o
FIG I]
2
3
4
5
1
8
(rp 35°)
q
B
10
It
OF HIGHWAY
ENGINEERS
VERTICAL DISPLACEMENT OF MOVABLE ANCHORAGE
(INS)
APRIL 1971
THE JOURNAL
OF THE INSTITUTION
27
Anchored Diaphragm Walls in Sand-Some
Design and Construction Considerations
I
JACK DIAL GAUGE
2
ANCHOR
3
GU N BAfl.REL
4
VSL
5
LOADING
6
COMB CASTING
MOVEMENT DIALGAUGES
JACK
PLATE
7
PRESSURE GAUGE
B
q
HAND
PUMP
JACK CONTROL
VALVE
CORRUGATED
TUBE
3
,
FiRlire 15. Diagram
00
000
50
500
40
400
SCALE
ot
the RIm barrel and ancillary
SCALE
A~~~OR JO
END CURVE
(XO'OOOI)
JOO JA~~1~6
END
CURVE
INS.
20
200
(00001
INS
)
CURVE FOR JACKING END
-A CURVE FOR PERIPK RAl STRANO ANCHORED END
10
x-x
I
f
CURvt FOI'. CENTML STRAND
ANCHOI'.ED END.
100
equipment.
soldier piles and the upper set of tiebacks were installed at the
bottom of an initial excavation 3 metres deep.
The lateral displacement of the wall at the end of the
excavation period is shown in Figure 17b. Subsequent movements were negligible. The soldier piles moved inward by
amounts decreasing with depth from a little over 50 mm at
the ground surface to about zero at the bottom of the cut, the
horizontal displacement of the top anchor being about 25 mm.
At another section in the same cut excavated to 6.4 metres,
a similar bracing geometry was used but the anchors were
prestressed to 110 per cent of the load calculated on the
basis of earth pressure at rest. With this prestress the horizontal
displacements of the top and bottom anchors were only about
0.5 mm and 0.25 mm respectively.
These results were achieved with average workmanship, but
it should be noted that inferior workmanship can easily lead
to larger settlements than those inevitably associated with a
given type of construcion and a given soil.
(
o
o
~
TIME-DEFLECTION
Figure
ro
ill
TIME DAYS.
~
m
0
MOVEMENT
INCHES
16.
0123
Lateral Movements and Settlements
Few records are available of the settlement of the ground surface adjacent to cuts in cohesionless sands, but Peck (1969)<'")
has assessed the available data on excavations using standard
soldier piles or sheet piles supported with internal bracing
or prestressed anchors, and states that if the sand is abov~
the water table or if the ground water has been lowered and
brought under complete control, adjacent settlement of dense
sand appears generally to be inconsequential. However the
settlements associated with loose sands and gravels may be of
the order H/200 at the edge of the excavation, diminishing to
negligible values within a distance of 2 to 3 H from the
excavation.
With regard to the influence of anchor prestress on lateral
displacement, a tie back system for bracing the soldier-pile
walls of an excavation 11.3 metres deep in dense sands overlain by a layer of loose sand is shown in Figure 17a (Rizz)
et al 1968). The tie backs consisted of driven H-piIes prestressed
to approximately 50 per cent of the load calculated for the
condition of active earth pressure. The wales through which
the tiebacks transferred their forces to the soldier piles were
located at the third points of the height of the wall, and the
18
LATERAL
CURVES FOf\. ANCHOR AND JACKING DIAL GAUGES.
THE JOURNAL
OF THE INSTITUTION
OF HIGHWAY
ENGINEERS
-0
~
LOOSE SAND
SOME SILT
~ -10
UJ
u._ -20
:I:
I-
~ -30
o
-50
SOLDIER
'1(
,
PILES
10
I
FEET
(B)
Figure 17.
APRIL 1971
Anchored Diaphragm Walls in Sand-Some
Pu~lished data on ground movements associated with
anchored diaphram walls in sand-is limited. but two interesting
case histories have recently been described by Maestre(l7) and
Vander Linden(18) at the Speciality Session No 14 of the
Seventh International Conferenc.e on Soil Mechanics and
Foundation Engineering in Mexico. In both cases lateral
measured movements of the walls were only a few millimetres.
As Peck has suggested the absence of settlement records at
least suggests the absence of serious s~ti1ements.
Conclusions
(1.) For an anchored or strutted continuous wall, a design
procedure is now available which takes account of soil properties, wall flexibility, wall construction procedure and mam
.excavation stages. Observations of the performance of models
and field structures to date indicate that the new method gives
realistic anchor loads.
(2.) The design method has been programmed for a computer
and if different soil conditions, from those assumed, are encountered on site, the design can be quickly amended panel by
panel.
(3.) Where specialist companies within one group possess the
expertise and experience to construct both the soil anchors anu
the diaphram wall, the programme can be employed to produce a quick optimum solution for the design and construction
of the anchored wall.
(4.) Excavation under bentonite to install a diaphragm wall
)fIers much better conditions compared with conventional
:rench excavation methods, since the bentonite supplies immediate support for the excavation and does not require pumping.
associated with the lowering of a ground water table ..
(5.) Soil anchors, employed for the support of braced cuts,
eliminate the need for. interior struts, which in turn brings
;,J,uitelarge economic and constructional advantages.
(6.) The use of a stiff continuous diaphragm wall supported
by prestressed anchors can greatly reduce lateral displacements
of the wall and therefore settlements of the retained soil mass
.during the main excavation.
(7.) More use should be made of field instrumentation to
observe the p~rformance of anchored. walls where the site
observations are related back to design assumptions.
References
(I) Rowe, P. W. (1956) Sheet Pile Walls at Failllre, Proc .
I.C.E. Part 1, Vol. 5, p. 276.
(2) Rowe, P. W. and Briggs, A. (1961) Measurements
on
Model Strutted Sheet Pile Excavations. 5th Int. Conf. on
Soil Mech. and Found. Eng. Vol. II, pp. 473-78.
(3) Golder, H. Q. (1970)
Gould, J. P.
Lambe, T. W.
Tschebatarioff, G. P ..
Wilson, S. D ..
Predicted Performance of Braced Bxcavation. Proe. Amer.
.J.
-'
.
Design and COllstruction Considerations
Soc. of Civ. Engs. (S.M, &
(Ma0
f.g. Div.) Vol. 96, No. SM3
.
(4) Morgenstern, N. R. and Amir-TahmasscJ,
stability
of slurry
trc/lches incohcsionless
I. (1965) Tire
soi/s. Geotech-
nique 15, No.4, 387-395.
(5) Nash, 1. K. T. L. and Jones, G. K. (1963) The support
of trenches using fluid mud. Proc. Symp. Grouts and
Drilling Muds in Engineering Practice, pr .. 177-180.
London: Butterworth.
(6) Schneehell, G. 1964. La .>tabi/ill! des tranchees pro/mules
foree,l' en presence de boue, Houille blance, 19: 7: 815820.
(7) Ved~r, C. (1963) Excavations of trenches in the prese/lce
of bentonite suspensions for the construction of impermeable and load bearing diaphragms.
Proc. Symp. Grouts
and Drilling Muds in Engineering Practice, p. 181. London: Butterworth.
(8) Wielicka, H. and Malasiewicz, A. (1967) Wplyw zjawisk
fizyko
chemiczllych
na
stosowanych do glevienia
WlaSrlosci
zawievill
ilowych
waskprzestrzennyeh
wykopow.
Archiwum Hydrotechniki 1967.
(9) Elson, W. K. 1968, Experimental
invesligatioll
of tire
stability of .I'II/rry trcnches. Geotechnique, XVIII, No.1,
pp. 37-49.
(10) Florentin. 1. (1969) Les Parois Moulees Dan\' Le Sol.
Proceedings of the Seventh International Conference on
Soil Mechanics and Foundation Engineering Speciality
Session 14 Mexico 1969. Vol. 3, pp. 507-12.
(11) Courteille, G. (1969) Aaron stabilisatrice des suspen. sions thixotropique
sur Ie parois de fOllille.l'. Communication due 14me Session Speciale Mexico 1969. Vol. 3.
pp.507-12.
(12) Road Research Laboratory (1950) Design of Concrete
Mixes Road Note No.4. H.M .S.o., London.
(13) ,Kranz, E. (1953) Ueber die Verankerung
vall Splmdwiindell.-W.
Ernst & Sohn, Berlin.
(14) Jelinek, R. and Ostermeyer, H. (1966) Verankerung
von
Baugrubenlllllschliessungen.-Vortrage
der Baugrundtagung 1966 in Munchen, Deutsche Gesellschaft flir Erdund Grandbau e.V. Essen.
-( 15) Ranke, A. and Ostermeyer, H. (1968) CorltribllliOIl to
IIle illvestigatioll
of stability of multi-tied walk Baulech.
nik. 10.341-50.
(16) Peck, R. B. (1969) Deep Excavatiolls and TUllnelling in
Soft Ground. Proceedings of the Seventh International
Conference on Soil Mechanics and Foundation Engineer. ing - Mexico.
(17) Maeslre, M. (1969) Incident following overloading of an
anchored diaphragm wall. Speciality Session No. 14. Proc.
7th Int. Conf. on Soil Mechanics and' Foundation
Engineering. - Mexico.
(18) Vander-Linden, J. (1969) Controle
des mouvements
horizontaux d'une parai moulIee dans Ie sol avec ancrages
precOIrtraill{s. Speciality Session No. 14 Proc. 7th Inter-
national Conference on Soil Mechanics and Foundation
Engineering - Mexico.
...
-:~
:: .. APRIL 1971
THE JOURN"L OF THE INSTITUTION OF HIGHWAY ENGINEERS
29
l
New plant, equipment and materials
New Tellus T Oils Range
The Industrial Markets Division, Shell-Mex and B.P. Ltd.,
Strand, London, W.C.2., have announced an improved and
extended range of their Tellus T Oils. These are very high
viscosity index hydraulic oils suitable for use in marine, earthmoving, machine tool and oil mist 'generation-equipment.
The old Shell Tellus TOils 17 and TeHiJs T 27 have been
reformulated to give better anti-wear properties and by the
use of a superior viscosity index improver, improved shear
stability.
Assessments of shear stability were conducted in accordance
with the U.K. Association of Hydraulic Equipment Manufacturers test procedure corresponding to severe use in
service. The loss in viscosity during these tests was less than
one third of that obtained on the old formulation. Two new
grades, TeUus T Oil 33 and Tellus TOil 72 have been added
to the range,
Cast Resin Cable Splicing Kits
CfL Comp~nents Ltd., 233/243 Wimbledon Park Road,
London, S.W.18, have introduced a new and comprehensive
range of cast resin cable splicing kits for aU cable types up
to 10 kV.
The crL Components range of kits includes connecting,
derivation, terminal and pole terrriinaf boxes for indoor and
outdoor cable work. They are supplied as a single system for
the cable connection to be undertaken.
The system is a modern cable jointing one of sound design
and high quality. It comprises unbreakable self-sealing plastic
moulds of high mechanical strength and a stress-free cold
hardening casting resin of minimum shrinkage. The casting
resin and hardener is supplied accurately measured in a tw.,
compartment plastic bag. Padding tape, pouring funnels and
full instructions are also supplied with each system. A standard
method of packaging and presentation is used for all kits.
The completed box has a high mechanical and electrical
loading, is absolutely watertight and does not corrode. crL
Components cast resin cable splicing kits offer substantial
savings in work time and are easy to use. They are light in
weight and require no re-pouring or hand contact during
application. The space required in storage and application is
reduced to a minimum and all kits in the range are available
at a competitive price.
Pouring casting resin into a plastic mould employed in the
Ilew CT L derivation box cast resin splicing kit.
APRIL 1971
Mobile Site Unit
A new design of Mobile Site Unit is being marketed hy
M.F.R. (Sales) Ltd., Cosgrove. Wolverton, Buckinghamshire,
of which a predominant feature is a replaceable roof and side
panels which make for simple repair in the event of damage,
The size of the basic unit is 17ft 6in. with alternative
versions of 14ft and 21ft; this simply means the deletion or
addition of a side panel. The unit chassis is of bridged longitudinals of rolled section transversely braced with box and
angle sections, all electrically welded as is the body frame on
which are mounted the roof and panels. The latter are insulated and clad externally with aluminium alloy and on the
interior with precoated hardboard.
The windows are of toughened glass, fully-opening, mounted
in a rubber frame. The unit is supplied as standard with
roof ventilators, toilet compartment, gas and electric lights
(terminal points inside and out) gas bottle carrier mounted on
towbar, corner stabilisers, hardwood rubbing rails and, as an
optional extra, a rear bumper incorporating a scrapper step
and tool box.
The complete unit is mounted on a full width axle through
semi-elliptic springs and the wheel/tyre equipment is interchangeable with that of the Land Rover.
[>,----','
'
~
-I'".t-!_
"
..
'.',
The flCIV mobile site rl/lit marketed by M.P.l~.
Cosgrove, W olvertoll, Buckinglwlltshire.
(Sales) Ltd.,
Penetrating Lubricant
Bell's Asbestos and Engineering Ltd., Farnham Road,
Slough, Bucks, a Bestobell company, has announced the introduction of Graphosol, a penetrating lubricant specially formulated to break down rust and lubricate-corroded or seized
components.
Graphosol consists of highly concentrated, micro-particle
graphite powder suspended in a rust solvent carrier. The oils
and solvents attack the rust allowing the ultra fine graphite
to penetrate deep between mating surfaces, thus easing the
movement of seized parts. The graphite and oil carrier will
continue to provide lubrication and prevent corrosion over a
long period of time.
As a penetrating fluid it will free seized or coqoded components such as pipe fittings, nuts, valves, and pistons; as a
lubricant the high graphite content provides low friction and
low wear in applications such as hinges, pivots, chains,
spindles, bearings slides, gears and guides. Even at
temperatures up to 600°c, when lubricating oils are destroyed,
the graphite continues to supply a thin lubricating film.
Supplied in a 12 oz aerosol can, with a flexible extension
tube, the lubricant is non-flammable and will not affect stove
enamel finish, nylon, ABS, polystyrene, acetal resin, poly"
thene, glass reinforced plastic, neoprene, plasticised PVC or
nitrile/PVC blend.
THE JOURNAL Of THE INSTITUTION OF HIGHWAY ENGINEERS
31
New plant, equipment and materials
Computer Service
The newly established Glen Computing Centre at Glen
House, Stag Place, S.W.I., provides a comprehensive computing service based on a broad series of specialised technical
programs. Aimed at the civil engineering designer and the
planning authority the service is a logical development to
meet a steadily increasing need.
The Centre has been set up by G. Maunsel1 and Partners
to make available to others the facilities formerly used solely
on their own work. The programs available have been
developed from Maunsell's experience over many years and
include perspective drawing.'
Hardware at the Glen Centre is based on an ICL 4120
machine with related keyboard punch and print-out peripherals. A Zeus precision flat-bed plotter reading punchedtape input produces highly accurate drawings from basic
numerical data.
One of the major jobs on which the computer was used,
and which led towards the establishment of the Centre, was
the Westway project in London, the extension of Western
Avenue to Marylebone Road.
The Glen Computing Centre has a range of fully docu.
mented civil engineering programs which can give a similar
service to projects of many kinds and these are described in
a series of pamphlets available from the Centre.
A
1IQ fOl0lD100DDDfJOODD
Ribblesdale
ee en.
B
cn
n
n
D
These cross-section drawings are of some of the West way
detaiLr and are typical of the Olltput from the Glen
Computillg Centre's tape-coil trolled plot/er. A=a portal bent.
B=a single pier and C=top-!lat hearns.
Li i'ed
ClITHEROE, LANCS
TELEPHONE:'ClITHEROE
2401
TELEGRAMS: RIBBLE TELEX CLiTHEROE
Offices also at :
MANCHESTER, LIVERPOOL & BRADFORD
Bulk supply depots at:
SHAP (Westmorland)
32
THE JOURNAL OF THE INSTITUTION OF HIGHWAY ENGINEERS
& BRADFORD
APRIL 1971
I
I
Institution matters
ELECTION OF MEMBERS
Total Membership to date 7,901
5th February, 1971
MEMBERS
Barbour, J. R. (Associate Partner,
W. V. Zinn & Associates)
Elver, J. (Assistant
Cou nty Surveyor
(Improvements).
Lindsey
C.C.)
Khan, M. S. M. (Executive Engineer,
Punjab Highway Dept., Govt. of
Punjab)
Roos, D. B. (Director of Civil Engineering, George law ltd.)
Roberts. l. (Group Resident Engineer, Sir Owen Williams & Ptnrs.)
Robinson. R. W. (Associate Partner,
John Burrow & Ptnrs.)
TRANSFERS FROM ASSOCIA TE
MEMBER TO MEMBER
Allen, C. D. (Assistant
County
Surveyor
(Special
Works
&
Bridges). Warks. C.C.)
Bergg, J. A. (Assistant County Surveyor. Kent C.C.)
Tharby. A. W. (Deputy County Surveyor, Stirling C.C.)
AFFIUATf
Shirley, D. J. (Traffic Management
Officer. Lindsey C.C.)
ASSOCIATE MEMBERS
Asman, S. A. (Assistant Engineer.
Runcorn D.C.)
Ballard, A. C. (Assistant Engineer,
Brian Colquhoun & Ptnrs.)
Bluck. M. C. (Assistant Engineer,
leatherhead U.D.C.)
Brown, J. C. (Deputy Area Engineer,
British Waterways Board)
Clarke, M. J. F. (Assistant Engineer,
R. Travers Morgan & Ptnrs.) (N.I.)
Coates, J. H. (Senior Assistant
Engineer, Boston- B.C.)
Davies, A. P. (Assistant
Civil
Engineer, Portsmouth City C.)
Dean, P. K. (Senior Assistant Engineer, Rutland C.C.)
Dean, R. (Senior Engineering Assistant, Midland R.C.U. (Staffs C.C.
Sub-Unit) )
Gorham. D. F. (Assistant Engineer,
Lindsey C.C.)
Hall, M. H. (Engineering Assistant
Morpeth B.C.)
Hodgson, M. (Engineer ijc (Outside
Supervision).
J. H. Coombs &
Ptnrs. )
Hurst. S. G. (Graduate Assistant
Engineer, Teesside C.B.C.)
Johnstone. A. J. (Civil Engineer.
Bett Bros. ltd.)
Jones. S. R. (Assistant Engineer,
Halesowen B.C.)
APRIL
1971
leary, A. T. (Project Engineer, Port
Talbot B.C.)
tleid, R. (Senior Assistant Engineer,
Renfrew C.C.)
Taylor. J. M. (Civil Engineering
Assistant, Killingworth D.C.)
Thornton, J. (Assistant
Engineer.
Waterhouse & Ptnrs.)
Tildesley. J. W. (Engineer, Dept. of
the Environment)
Toner. I. (Assistant Engineer, Gnl.
Directorate of Turkish Highways)
Whittaker, C. E. (Assistant Engineer, Warks. C.C.)
Wiggins. M. K. (Assistant Engineer
(Bridges).
South-Eastern
R.C.U.
(Hampshire C.C. Sub-U nit) )
Wilkins, D. J. (Assistant Engineer,
London Borough of Kingston upon
Thames)
Williams, A. (Assistant
Engineer,
Northampton C.B.C.)
TRANSFERS FROM STUDENT TO
ASSOCIA TE MEMBERS
Bamber, B. (Assistant
Engineer,
Stirling Maynard & Ptnrs.)
Guthrie. R. F. (Assistant Engineer,
Lindsey C.C.)
STUDENTS
Hayward, M. E. (Postgraduate Student at Univ. of Birmingham)
Jenkinson, M. (M.Sc. Student at
Univ. of Birmingham)
PERSONAL NOTES
Bentall, P. H.• has taken up the post
of Resident Engineer with Howard
Humphreys (East Africa) and is engaged on the West Kenya Feeder
Roads.
Chapman, R. J., has been appointed
Chief Engineering Assistant for the
Central Area Section, Northampton
Borough Council.
Elliott, D. R.• has taken up the post
of Principal Engineer (Highways)
with Warrington Development Corporation.
Forde, M. C., has been awarded an
M.Sc., Degree in General Highway
and Traffic Engineering from the
University of Birmingham.
Maclean, D. H., has been appointed
Divisional Road Surveyor (Upper
Division) with Banff County Council.
Mismarl, A. L.. has now returned to
Caylon.
Murray, G. L., is now with Ove Arup
and Partners, Northern Nigeria.
Rehncy. S.• has taken up the post of
Structural Engineer with Fenton G.
Keyes Associates,
Rhode Island,
United States of America.
THE JOURNAL
Royle. H. B., formerly Group Engineer (Roads) Essex County Council
has
been
appointed
Assistant
County Surveyor, Buckinghamshire
County Council.
'
Sharples, C. G" has taken up a post
with Warrington Development Corporation.
Spiller. R. M., has been awarded an
M.Sc. Degree in Bridge Engineering
from the University of Surrey.
Stamper, H. T., formerly Section
Engineer with Cumberland County
Council has taken up the post of
Assistant Resident Engineer with
Somerset County Council.
NATIONAL CONFERENCE.
DECEMBER. 1971
The Institution's
National Conference will be held at Church House,
Great Smith Street, Westminster,
S.W.1. on Thursday and Friday,
December 9th and 10th, 1971. The
theme for this year's Conference will
be that of "Urb"an Transportation"
and, as in past years, the programme
will be divided into an all-day session on Thursday and a half-day.
morning session on Friday. The
Annual luncheon will follow immediately after the conclusion of the
Conference and will be held at the
london Hilton Hotel, Park lane, W.1.
The names of the authors taking
part and the provisional titles of the
Papers which they are presenting
are detailed below:
Thursday. 9th DecemberMorning Session
"Urban
Transportation:
Problems
and Progress". Professor T. E. H.
Williams. Head of Department of
Civil
Engineering,
University
of
Southampton.
"Urban Transportation and Environment", A. Wood.
City Planning
Officer, Norwich City Corporation.
Afternoon Session
"Public Passenger Transport",
F.
Lloyd, Director.General, West Midlands Passenger Transport Executive.
"Goods Transport", M. Brown, ViceChairman, S.P.D. Ltd.
Friday. 10th DecemberMorning Session
"Road Traffic Management, control
and safety," I. Armour. Master of
Works and City Engineer, Glasgow.
"Highways Construction", (i) A. T.
B. Shand Chairman and Director.
Lehane M~ckenzie & Shand Ltd. and
(ii) D. Dennington, Traffic Commissioner. Greater london Council.
OF THE INSTITUTION
OF HIGHWAY
'ENGINEERS
33
\'
\
Institution Matters
Registration forms and full details
will be sent to all members of the
Institution later in the year.
EAST ANGLIAN
BRANCH DINNER
The Annual Dinner of the East
Anglian Branch was held at the Norwood Rooms, Norwich on Friday,
February 12th, 1971, and 134 members and their guests attended.
Extract from Chairman of Finance
The Toast of "The Institution"
Committee's Reportto Council on
8th January 1971
was proposed by Mr J. T. Brookes,
In reporting to Council on January 8th Manager of the Metropolitan and
1971 on the Annual estimates, Mr L. P. Harlow Region of the Eastern Gas
F. Hubbard, Chairman of the Finance Board, and the Response was given
Committee, drew attention to the fact by the President of the Institution,
thatthe budget for 1971 forecast a small Mr H. K. Scott, a.B.E., County Surdeficit even after allowing for a sub- veyor of Londonderry. The Chairman
stantial estimated profit on the National of the Branch, Mr R. J. NichoJas,
Conference to be held in London welcomed the guests and expressed
towards the end of the year. But for the regret that Mrs Scott was unable to
Conference the deficit would have be present on this occasion.
Amongst the guests attending
been much larger.
Mr Hubbard went on to say that for were Mr A. Alsop, M.B.E., Chairman
some years past the growth in mem- of the East' Anglian Association of
bership had been running at about nine Civil Engineers, Mr J. H. Gibson,
to ten per cent per annum so that the Chairman of the East Anglian Secnecessary increases in Institution ex- tion of the Institution of Structural
Engineers, Mr A. W. K. Tucker,
penditure had been contained within
existing subscription rates. Priceswere Chairman of the East Midland
now rising rapidly and it appeared Branch of the Institution, Mr R. F.
Earley, Chairman of the Greater Lonhighly probable that the Institution
would soon need to increase its income don Branch of the Institution and
thus necessitating a rise in subscrip- Mrs Earley and the Secretary of the
tions. Mr Hubbard pointed out that the Institution Mr M. J. Hall.
The Branch was also pleased to
present subscriptions were well below
those for comparable Institutions and welcome a record number of reprehad been in force for about six years sentatives from local commercial
so that it was not really surprising that firms connected with highway work.
the possibility of an increase had now
arisen. He said that a further review of NORTHERN BRANCH
the situation would be.undertaken by ANNUAL DINNER
the Finance Committee at its April
Close on 150 members and their
meeting fallowing which he would
guests attended the Annual Dinner
report again to Council.
of the Northern Branch of the Institution held at the George Hotel, Penrith, CumberJand on Tuesday, FebNO RTH EASTER N
ruary 16th, 1971.
BRANCH DINNER
The Toast of "The Institution"
was proposed by Mr C. H. D. AckThe Annual Dinner and Dance of the land, a.B.E., North Western Agent,
North-Eastern Branch of the InstituNational Trust to which the Presition was held at the Civic Centre, dent, Mr H. K. Scott, O.BE,
Barras Bridge, Newcastle upon Tyne, County Surveyor of Londonderry
on Tuesday, November 10th, 1970, replied.
whe'n 140 members and their guests
The County Surveyor and Bridgewere present.
master, Cumberland County Council,
The Toast of 'The Institution"
M~ J. A. Davison, proposed the
was proposed by the Rt. Hon. the Toast of "The Guests" and the
Lord Chesham, P.C., Chairman of Response was given by Mr J. K. M.
the British Road Federation and Henry, Partner, Scott WiJson KirkExecutive Vice-Chairman of the patrick and Partners, Consulting
Royal
Automobile
Club.
The Engineers.
Response was given by Mr H. K.
Amongst the guests attending
Scott, M.B.E., County Surveyor of this function were Mr J. Patrick
Londonderry and President of the and Mr R. O. Bradbury, respectively
Institution.
Chairman and Honorary Secretary
Among the guests present on this of the Cumbria Branch, Northern
occasion were Mr R. D. Butler, ViceCounties Association of The InstituChairman of the Northern Branch of tion of Civil Engineers, Professor
the Institution and Mrs Butler, Mr W. F. Cassie, Chairman of the
J. L. Hurrell, Chairman of the NorthNorth-Eastern Branch of the InstituEastern District of the Institution of tion and Mr S. Plews th-e Secretary
Municipal Engineers and the Secre- of the Branch, Mr J. D. Wallace,
tary of the Institution Mr M. J. Hall. Chairman of the North-Western
INSTITUTION
SUBSCRIPTIONS
J4
THE JOURNAL
OF THE INSTITUTION
OF HIGHWAY
ENGINEERS
Branch of the Institution and Mr
M. J. Hall, the Institution's Secretary.
HEADQUARTERS AND
BRANCH MEETINGS.
April-May,1971
Headquarters
May 7th, 1971
'The Servicing Arrangements of the
Rungis Market". Paper by M. Andre
Darlot, Associate Director (Technical),
Marche d'Inten3t National de la Region
Parisienne. Joint Meeting with the
Societe des Ingenieurs Civils de France
(British Section) at Lecture Hall,
Institution of Civil Engineers, Great
George Street, S.W.1.
May 20th, 1971
Joint Meeting with the Royal Institu.
tion of Chartered Surveyors and the
Photogrammetric Society. Paper by
Mr W. F. T. Austin, Freeman Fox and
Partners, and Mr W. A. Parkes, B.K.S.
Surveys, on the Ministry of Transport
specifications for survey work. Meeting
atthe LectureTheatre, Imperial College,
S.w.7, at 5.30 p.m. for 6.15 p.m.
Northern
Ireland Branch
April 26th, 1971
''In the Beginning". Film and talk on
Lancashire/Yorkshire Motorway by
F. R. Oliver, Deputy County Engineer,
West Riding C.C. Meeting to be held
at Lecture Theatre, L.G. 25 David Keir
Building, Queen's University, Belfast.
Central and Southern Scotland
Branch
May 10th, 1971
AnnuaJ General Meeting at Appleton
T<?wer,Edinburgh.
North of Scotland Branch
Apri/19th, 1971
Annual GeneraJMe~ting at Inverness.
South Eastern Branch
May 14th, 1971
Wine and Cheese Party.
South Midland
Branch
Apri/29th, 1971
Annual General Meeting followed by a
talk and film on the "Construction of
Vauxhall Motors Proving Ground at
Lidlington." Meeting at the BeechTree,
Maxwell Road, Beaconsfield ~It 7.15
p.m.
South Wales Branch
Apri/30th, 1971
Annual General Meeting and Annual
Dinner at the Park Hotel, Cardiff.
APRIL 1971
I
"
Institution Matters
South Western
Branch
April 28th., 1971
Visit of inspection to Cardiff-Central
Redevelopment Scheme.
West Midland Branch
May 19th. 1971
Visit to the works of Aveling Barford
Ltd., Grantham.
Yorkshire
Branch
May 13th. 1971
"Conservation in the Countryside."
Paper by Mr Bliss, Horticultural Officer,
West Riding Highways and Bridges
Department. Meeting at the Beverley
Arms Hotel, Beverley, at 7.00 p.m.
NEW CEMENT AND
CONCRETE ASSOCIATION
PUBLICATIONS
A number of new publications, described below, are available from
Publications
Orders, Cement and
Concrete
Association,
Wexham
Springs, Slough SL3 6PL, at the
price indicated. The reference number of each publication should be
quoted when ordering.
The Constnlction And Testing
Of A One-Sixteenth Scale Model For
The Prestressed Concrete
Superstnlcture Of Section 5,
Western Avenue Extension.
R. A. Swann 42.441
The report describes the construction and testing of a micro-concrete
model of a typical span of a six-lane
viaduct built from precast segments.
The segments of the model were
transversely and vertically stressed;
longitudinal prestress was applied
to the completed span, together with
simulated dead weight. The model
was tested under ten potentially
critical combinations of Ministry of
Transport
HA and HB loading.
Finally the model was tested to
failure, using two of the live load
configurations and a number of concentrated loadings. The effect of the
transverse prestress was determi ned
by testing a one-tenth scale Perspex
slice. Price 10s (SOp).
The Effect Of Aggregate Size And
Grading On Initial Air Drying
Shrinkage. A. R. Mears 42.449
This report describes a series of
tests in which measurements were
APRIL 1971
. made of the air-drying shrinkage of
concrete specimens of constant mix
proportions
but varying aggregate
grading. It was shown that the
equilibrium shrinkage of specimens,
of specified dimensions drying at a
specified temperature
and relative
humidity, is independent of aggregate grading and maximum aggregate size. Specimens of relatively
smaller size reached equilibrium in
about a quarter of the time taken by
the larger specimens. Price £1.
Computer Analyses of Reinforced
Concrete Portal Frames With
Fixed Feet. W. B. Cranston and
A. K. Chatterji 42.444
Analyses for seven different portal
frames are described, these being
frames of a series previously tested
in the laboratory. Each frame was
analysed three times under different
loading conditions,
one of which
simulated the loading applied in the
laboratory test. The results are compared with the actual test data,
where appropriate, and also with
results
obtained
using
simple
mechanism theory. It is concluded
that the idealisations made in the
computer analysis lead to a reasonably accurate reflection of the actual
behaviour of the frames, and that the
use of mechanism theory for the
analysis of such frames ;s justified.
Price £1.
The Use of Disposable Cardboard
Moulds For The Production Of
8 x 4 Inch Diameter Lean Concrete
Test Cylinders. R. G. Chaplin
42.445
Tests have been made to assess
whether cardboard tubes might be
used in place of the 8 x 4 inch diameter steel moulds specified in BS
1924:1957 when casting test cylinders for the determination of the unconfined compressive
strength of
cement-stabilised
materials. Unconfined compression and indirect tension tests on specimens of lean concrete show that the reproducibility
is similar for both types of mould
but that the mean strength is higher
when specimens are cast in cardboard moulds. It is shown that the
use of cardboard moulds can result
in considerable economies in equipment and labour. Price £1.
THE JOURNAL
METRICATION GUIDE
A guide entitled "Metrication
Tar
Binders and Coated Materials" has
been prepared by the British Tar
Industry Association. The object of
the guide and tables is to give practical help and useful references on
the use of S.1. units.
From January 1st, 1971 all sales
of bulk tar products have been in
tonnes with invoicing
in decimal
currency.
The guide, in the form of a stiff
card printed on both sides, is available from the British Tar Industry
Association, 9 Harley Street, London, W1 M 1DA.
THE ASSOCIATION OF
HIGHWAY TECHNICIANS
Total Membership to date 926
5th FEBRUARY, 1971
ELECTED TO MEMBERSHIP
Goodman, D. R. (Traffic Engineering
Technicia n, Warwickshire
C.C.)
Rose, A. R. G. (TeChnical Assistant,
Essex C.C.)
ASSOCIATION MEMBERS
VISIT CONTAINER
TERMINAL
Members
of the Association
of
Highway Technicians in Central and
Southern Scotland enjoyed an interesting and informative visit to the
Clyde
Container
Terminal
at
Greenock on the afternoon of February 10th, 1971. The visit was wellattended and, although
no ships
were in the Terminal at the time,
members saw the methods used in
handling containers and the rapid
turn-round of ships and road and rail
vehicles which this method makes
possible. The importance
of good
road communications
to and from
the terminal was apparent.
A Paper on "Traffic Management"
was given at Falkirk Technical College on March 27th, 1971 and a
social evening is planned for April
21st. It is hoped that a large number
of members will attend this function so that they can meet each
other and assist in the formulation
of a programme for the next session.
Of THE INSTITUTION
OF HIGHWAY
ENGINEERS
3S
,
,.
..
INSTITUTION
AND ASSOCIATION
TIES
Illustrated here are the designs for the Institu'tion of Highw~y Engineers tie
(left) and that of the Association of Highway:Technicians (right).
The Institution tie, with rts gold 'H' motif, is produced in three colours,
blue, green and /""Iaroonand is manufactured in terylene/crimplene.
The Association tie is manufactured in maroon only and bears a gold
pattern representing road markings. The price of all ties is £1.00.
Institution or Association members wishing to purchase a tie, or ties, are
asked to complete the appropriate form below .
..
Tie Order Form
To:
The Secretary,
,
Institution of Highway Engineers, '..
14 Queen Anne's Gate, London, S.W.1 ..
Please supply ......... 'Institution tie (s)
,
4
<
I
••
_
~
at £1.00 'each.
c;'" ~, ..--.......
Cheque/Postal Order/Money. Order fo~ £
Highway Engineers" ..
Name
o
Blue
0'
Maroon
o
Gree.n.. ,...
enclosed and crossed and made. payable ~o "The In$titution of
(F/M/Aff/AM/Stud)
(BLOCK CAPITALS PLEASE)
Address
:
:
:1
:
~
:
~~. , .. ~
.~
'.
, ~
Date
.
.
-
.
Please note: These ties may be worn by Members of the Institution only.
Tie Order Form
To:
The Secretary,
Association of Highway Technicians,
14 Queen Anne's Gate, London, S.W.1
Please supply
Association tie (s) at £1.00 each
Cheque/Postal Order/Money
Highway Technicians".
Name
Order for £
enclosed and crossed and made payable to "The Association of
.
(BLOCK CAPITALS PLEASE)
Address
,
.
.. --
.
Date
.
Please note: This tie may be worn by Members of the Association only.
36
THE JOURNAL
OF THE INSTITUTION
OF HIGHWAY
ENGINEERS
APRil
1971
.-------------------------------------------i
'~fW..en~it 'comes to~a'-d-m-.a-k-in-g-.-':1
i
From just one source, you can get top
grade bitumen, cutback bitumen, pitch/
bitumen, together with bituminous joint
sealants for concrete pavements.
Oils and greases to help keep plant on the
move, degreasers to clean things up,
concrete release agents and a safe and
efficient hand cleanser thrown in for good
measure! And this one source - jf you
l-;-~e~ion
Grade Bitumen:
C~IYing
With~l:-;-o-f-~e-::re
B53690. 1970 for use in macadams and asphalts.
Liquaphalt
Cutback Bitumen:
Complying with Table 2 of
B53690, 1970 for use in macadams and surface dressing work.
Pitch/Bitumens:
An ideal and economical binder for
asphalts used in surfacing main roads and motorways.
.
C t
J' t Sit
5
. II did
b
or on om
ea an s: peclil y eve ope
y
O S uperlor
Berry Wiggins and complying to B52499. 1966.
Io
Io
II
0
I
I0
I
Io
Io
Plant Oils: A full range of Industrial Lubricants. including
engine oils qualified to D.E.F. 2101 D. M IL- L-21 048 Series 3;
hydraulic oils. and general and special purpose lubricants and
greases.
Release Agents: To obtain a scab-free strike without
damage to the concrete or shutter. to produce blemish free
concrete and preserve the shutter for maximum re.use.
Degreasers:
For simple and economical cleaning of plant.
concrete or masonry without staining or corroding, use Berrilex.
Hand Cleanser: Muvmax industrial hand cleanser is
L~gienic~::i~
APRI L 1971
effici~nd
fa:.:d
easy to ~
haven't already guessed - is Berry Wiggins.
And to prove it, here's a check Iist of the
amount of ground we cover.
Kingsnorth-on-the-Medway,
Telephone: Medway 46600.
Hoo, Rochester, Kent.
I
I
I
I
I
ju:':me
Of~
Berry Wiggins products t~~1
day give service to Civil Engineers throughout the country. All
Berry Wiggins products are made to the very high standards
that can only be obtained by the knowledge and experience of
nearly 50 years in the industry, That is your guarantee .of quality.
You can find ?U~more about an,y of these BerrY,~lgg!ns
products by ticking the appropllale boxes and filling In the
coupon now.
Name
I
Position
I
I
I
Company
Address
:::.~=-
-
~H~~I
WBW
THE JOURNAL OF THE INSTITUTION OF HIGHWAY ENGINEERS
1~2
37
Traffic measures
to assist buses
The Council is cxp;:mding its 'Bus Unit' so that more work can b('
done LO improve existing mel~od!l. of easing bus flow, anJ to
de\ii'\C and develop new ways to assist bus operation.
Tl;C
T raffie Surv~y Section wLll asslst with the evaluation of particulJr
schemes and initiate a regular progr-anunc of parking survcys.
Applications are invlt.ed fat'
BUS UNIT
I. Team Leader (up to £3,5Z5) who should have considerable
ex.pcrie-nce to traAte cngineering and bus operations. together wil h
proven managerial ability and initiative. AppUc:anlS should t..e
charlered eng~neers.
Z. Assislant Engineer (up to £2,880) to develop and prace"
individual schemes; must be a professional enaineer with some
experlence in traffic engineering.
3. Tochnical Officers (up 10 £2,481 aad £2.193) to help in preparing
propos.als and surveying sites. ".N.C. or equivalent quaJific.adons
required or relevant technical cx.pericnC'e~ Ability to draw an
aUvilntagc:.
TRAFFIC SURVEY SECTION
4. Researcb Officer (up 10 £2.880) responsible 10 the section
leader for the organisation and tvaluation of s.urveys. Candidates
shol,ltd have a university degree or equivalcnt qualification.
5. Technical Officer (up to £1.8Z7) to assist the Research Officer.
O.N.C. or equivalent qualifications required or relevant technical
expertence ..
~
UNIVERSITY OF LIVERPOOL
Department
of Civil Engineering
Applications arc invited for two vacant posts of lecturer in the
Department of Civil Engineering. The Department is particularly
anxious to supplement its teaching and research in the fields of
(i) Highway Materials and Construction
Resources and Public Health Engineering
(iii) Surveying
(ii) Water
:Ji:.
1'~;:The
initial salary will be within the range £1,491 to £2,454
per annum, on a scale rising to £3,417 per annum according to
qualifications and experience.
Further information and application forms may be obtained
from The Registrar, The University, P.O. Box 147, Liverpool 169
3BX, by whom the completed application forms should be received not later than 17th May, 1971.
Quote Ref: RVf7410fJ.I.H.E.
Slarling sala,l~$ accordin,l1O qualifications and ~xp~rtenCt. Application forms from Joint Dir~clor. Departml"rrt of Planning.& Trans".,rlation (AI £01798/ C). County HaJl. S.E.l. Please stale position
for which application i. bdng made.
GREATER LONDON COUNCIL
Department of Planning & Transportation
,- .
38
THE JOURNAL
OF THE INSTITUTION
OF HIGHWAY
ENGINEEIl.~
APRIL 1971
...--------------------,1,j
j
I
,
I
i
~
~. :,
'~'F'"
\
;
.~.. '
.~.',
'\.
uPVC pipes specified fQ~IZii1gsLynn B.C.
'and NWNorfolk Water Board ~s~h~P1i:d~ Crossesanother bridge
,
When completed, this bridge will serve the heavy road traffic from ~ing's Lynn and East Anglia to
the A17 and A47 trunk roads. IUs being built by the Dredging and Construction, Co. Ltd, contractors for
Norfolk County Council (Eastern R.C.U.).
The new bridge also carries the sewage and water mains, the latter in two 12" (325mm) diameter
uPVC CHEMfous Class 'C' pipes, fitted with integral'push-type 'Z' joints, as specified by the North West
Norfolk Water Board.
-',
Two 24. (610mm) diameter Chemidus sewage pumping m~ins are being installed by Kier Ltd, to
the design of Binnie & Partners, for the King's Lynn Borough Council.
.
CHEMIDUS uPVC was chosen because (1) it is lighter, easier to handle, and easier to cut on site,
(2) quick delivery could be guaranteed, (3) it means lower carrying charges by the bridge authority, (4) its
flexibility ensures that the pipeline will take up the correct alignment, without undue stressing, after
settlement and (5) its high corrosion resistance is invaluable beyond the bridge, ~here the sewage
pumping main passes through the grounds of an old chemical factory ..
Write for full details of CHEMIDUS uPVC pipes with 'Z' joints for water, drainage and effluent
pipelines from Chemidus Plastics Ltd, Dept. 18F Cobb's Wood, Ashford, Kent.
,
101
24' (610mm) dia ..$ewage Pumping mains and 12' (325mm) dia. Class 'C' Water Main Insulled on the King's Lynn New Bridge. Consullanls-Blnnie
Contractors-The
Dredging &. Construction Co. Lid, Kier Ud, and North West Norfolk Water Board.
'
& Partners.
-~-----:---------------..--II
re
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'lO
THE JOURNAL
Of THE INSTITUTION
REFLEOTING ROADSTUDS LTD., BOOTHTOWN, HALIFAX, ENGLAND
Of
HIGHWAY
ENGINEERS
APRIL 1971
Road budgets
go further with
PFA Basemix.
Costing less than an equivalent volume of
lean concrete. PFA Basemix gives a firm, high
quality base for roads. car parks, factory floors
and similar surfaces. What's more. users have
generally found that they can save on the
amount of expensive surfacing when it is
required. Plain facts worth noting in these
days of financial restriction.
PFA BASEMIX is a critically controlled
pre-mix blend of cement, PFA and additives,
with the addition of water. Ready for laying
and compacting with n'ormal plant.
form and has proved to be a money-saver when
used to fill in abandoned mine shafts. sewers,
basements and other cavities. It flows far more
easily than other aggreg ate sl urries.
Ensures a quicker job. better filling of voids,
fewer points of entry. Provides greater strength.
For information contact: BASEMIX L1M ITED
Saves money on infill work, too!
PFA BASEMIX can also be used in a slurry
PFA. Marketing Officer, CEGB, Sudbury House.
Newgale Street, London EC1.
North Western :
Powell Duffryn House, 28/30 Dudley Road, Whallev Ranye, Manchester M16 BOD
061-2261188
So uth Eastern :
Equitable House, Lyon Road, Harrow, Middlesex. 01-427 B855
For general information about PFA and its uses. contact:
Year . • •
"---.
-C---l
~fter year . • •
••
Aughton By-pass, Lancashire, was constructed
in 1937 of concrete reinforced with BRC fabric.
Maintenance costs on this road to date have
been negligible, even though the traffic will
have increased in 1971 to an estimated 16,000
vehicles per day, including heavy dock transport,
Experience proves
REINFORCED
CONCRETE ROADS
require the least maintenance
and cost no more to build
The British Reinforced
Concrete Engineering
Co. Ltd" Stafford
I"I-w.
Prinled
by Thame.moulh
Printinll
Co,
Ltd .• Service House,
Slock
Road,
Southend.on.Se.a.
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.
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