September 12, 2014
MEMORANDUM FOR: Record
SUBJECT: Site Visit – PIANC WG 173 – Panama Canal
1. The subject site visit was conducted on Wednesday, September 10th and Thursday,
September 11th, 2014. Corps of Engineers attendees included Timothy Paulus (MVP)
and Brenden McKinley (LRH) and Rick Schultz (RMC). The site visit was conducted as
part of the second meeting of the PIANC Working Group 173 – Movable Bridges and
Rolling Gates Design, Maintenance and Control Lessons Learned from experience. This
working group will focus on mechanical and electrical issues related to rolling gates and
movable bridges. Participants in the meeting and site visit included the following:
Participants:
Brenden McKinley (USACE, USA)
Timothy Paulus (USACE, USA)
Rick Schultz (USACE, USA)
Pieter van Lierop (Iv-infra, The Netherlands)
Gerard Bouwman (Rijkswaterstaat, The Netherlands)
Wouter de Man (Rijkswaterstaat, The Netherlands)
Dan Boich (St. Lawrence Seaway, Canada)
Ralf Weisenseel (DriveCon, Germany)
Matthias Schafers (IRS-GmbH, Germany)
Johnny Wong (Panama Canal Authority - ACP)
2. Site visits were conducted over a period of two days. The meetings and site visits were
hosted and conducted by the Panama Canal Authority (ACP or Autoridad del Canal de
Panamá). The ACP representative was Mr. Johnny Wong. Mr. Wong works as a Project
Manager for Third Set of Locks with ACP. On Wednesday, September 10th, the PIANC
working group took a boat from the Pedro Miguel Lock to the Gatun Lock. The group
visited the Gatun Lock, the maintenance and dry dock facility, and the observation and
visitor center for the new Atlantic Locks. Four new rolling gates were just delivered and
the working group went to see these along with several other gates being stored and
awaiting installation.
On Thursday, September 11th, the working group visited the new rolling gate machinery
storage buildings, the new Pacific lock construction, and the Miraflores lock. The
existing locks allow the passage of Panamax container vessels that can carry up to 5,000,
20-foot equivalent units (TEUs) and or 70,000 dead weight tons (dwt). After the new
expansion work, the Post-Panamax vessels will be able to transit through the Canal, with
container ships up to 13,000 TEUs and cargo ships up to 170,000 dwt. The working
group team was provided a tour on the on-going construction of the Pacific Lock. The
new locks on both the Pacific side and Atlantic side are scheduled for completion in
1
December 2015. August 2014 marked the 100 year anniversary of the completion of the
Panama Canal.
Working Group 173 in front of new rolling gates
Working Group 173 at Panama Canal Authority headquarters
2
2.1 Panama Canal Boat Trip and Background Information. As noted above the
working group took a boat from the Pedro Miguel lock to the Gatun lock. The group
disembarked from the boat just before the Gatun lock. The entire Panama Canal is
approximately 80 km or 50 miles long from ocean to ocean and traverses the Isthmus of
Panama. A typical cargo ship takes 8 to 10 hours to transit the entire canal and the locks
and an average of 24 hours including waiting time at the ocean anchorages. The canal
crosses the continental divide near the Culebra cut which is the narrowest part of the
canal. Gatun Lake was created as part of the original Panama Canal project and the locks
lift vessels up to this level from sea level. The operating elevation of Gatun Lake is
approximately 26 meters (85 feet). It will be raised to 27 meters as part of the new
expansion work to increase its water storage capacity.
The locks on the Pacific side include Miraflores and Pedro Miguel. The Miraflores lock
is a double lift lock (essentially two lock chambers back to back). The Pedro Miguel lock
is a single lift lock. The only lock on the Atlantic side is the Gatun lock which is a triple
lift lock. All the locks have two lanes.
The new lock construction will provide a third transit lane. Grupo Unidos por el Canal
(GUPC) is the contractor for the design and construction of the third set of locks. There
will be a new lock on the Pacific side and another one on the Atlantic side. Each lock will
be a triple lift lock (three locks back to back to back). The Panama Canal expansion
project will also raise the operating level of Gatun Lake and widen the Culebra cut,
doubling the Canal’s capacity from the existing 340 million tons per year to over 600
million tons/year once the Third Set of Locks is operational.
The existing locks are utilized 24 hours per day and 7 days a week. On the day of the site
visit, 38 ships transited the canal and another 98 ships were waiting either on the Atlantic
side or Pacific side. The Panama Canal Authority offices are located in Panama City on
the Pacific side. The Panama Canal Authority is an autonomous state entity that is tasked
by Panama´s constitution to operate, maintain and improve the Panama Canal. The ACP
took over the operations and responsibility of the Panama Canal at noon on 31December-2014. There are almost 10,000 people employed by the Panama Canal
Authority.
3
The original lock canal plan called for one three-step set of locks at Gatun, one step at
Pedro Miguel and a two-step set at Sosa Hill, separated by Miraflores Lake. In late 1907,
it was decided to move the Sosa Hill locks further inland to Miraflores, mostly because
the new site provided a more stable construction foundation, but also because it afforded
greater protection against sea bombardment.
The locks took their names from geographic names already in common use before the
Canal was built. All lock chambers have the same 110 foot by 1,000 foot dimensions,
and they are built in pairs. That is, two lanes of chambers run side by side to
accommodate two lanes of traffic, either in opposite directions at the same time or in the
same direction, depending on transit needs. Gatun Locks consists of three steps or pairs
of chambers, there is one step at Pedro Miguel and two at Miraflores, making six pairs,
12 chambers in all.
Three men, Lieutenant Colonel Harry Hodges, Edward Schildhauer and Henry
Goldmark, were largely responsible for the engineering design of the locks. Hodges was
an Army officer and had overall responsibility for the design and construction of the lock
gates, arguably the most difficult technical responsibility of the entire project. Goethals
was to state that the Canal could not have been built without Hodges. Schildhauer was an
electrical engineer and Goldmark was in charge of lock gate design.
Two primary bridges cross the canal near Panama City. This includes the Bridge of
America (1962) and the Centennial Bridge (2004). A third bridge is being built on the
Atlantic side to be finished in 2016.
4
View from canal looking south at Centennial Bridge
Panamax Container ship transiting the canal
5
Another container ship on the Canal
The working group passed though Gatun lake during the boat ride. The level of the lake
was approximately 0.90 m (3 feet) lower than average. However, rains have started and
lake is expected to fill by the end of the year. As a result, off the main channel, tree
trunks were protruding above the lake. As part of the new expansion, the level of the lake
will be raised.
Tree trunks protruding above Gatun lake as a result of the low lake level
6
2.2 Gatun Lock. The working group visited the Gatun lock after disembarking from the
boat. The existing Gatun lock chambers are 33.5 meters wide (110 feet) and 304 meters
(1000 feet) long. The Gatun lock is a triple lift lock with two lanes. It lifts vessels from
the Atlantic Ocean up to Gatun Lake 26 meters (85 feet) above sea level. Unlike the new
locks under construction, Gatun lock has no water saving basins and it operates with
miter gates.
The Gatun lock (as does Miraflores and Pedro Miguel locks) utilize electric locomotives
to move the ships through the lock. The locomotives attach to the ships with two steel
wire rope or cable of 25mm diameter. These are reeled in and out by an electricalhydraulic winch. It typically requires 6 to 8 locomotives on the larger vessels to help
move the ship through the lock. The original electric towing locomotive system was
designed to provide complete control over the movement of vessels transiting the locks.
The locomotives work on track built atop the lock walls operating at a speed of about 2-3
miles per hour. An important design factor was that they have to travel the 45-degree
incline between the lock chambers, for this it has a rack on lock floor along the tracks and
a drive pinion on the locomotive. The original locomotives were built in Schenectady,
New York, at a unit cost of $13,000 each.
Original locomotive next to newer locomotive at Gatun lock
At all the locks including Gatun, the filling culverts run under the lock floor. Water is
admitted or released through the main culverts, eighteen feet in diameter, running
lengthwise within the center and side walls of the locks. Branching off at right angles to
7
these culverts, smaller culverts run laterally under the floor of each lock chamber, 20 to
each chamber. Each cross culvert has five openings for a total of 100 holes in each
chamber for the water to enter or drain, depending on which valves are opened or closed.
This large number of holes distributes the water evenly over the full floor area to control
turbulence.
Disembarking from boat at Gatun lock
Gatun Lock – two Panamax ships going through the middle lock
8
Gatun lock central control house and operating building
Observation platform at Gatun Lock – note double set of miter gates
9
Gatun lock – cargo ship being moved to next level in lock – note the locomotive next to
the container ship going up the incline
2.3 Maintenance Facility and Dry Dock Facility. The Panama Canal Authority
operates a repair and maintenance facility. The vessels are raised out of the water in a
synchro-elevator that raises a table with rails and then are pulled out in the dry for
repairs, therefore avoiding the need to dry dock the vessels. The working group was
provided a tour of this facility. The ACP uses the facility for repair and painting of miter
gates, vessel repair, etc.
10
ACP tug in dry dock and undergoing repair
Miter gate painted and overhauled
11
Pintle bushing with new greaseless technology installed on miter gate
The Panama Canal Authority is in the process of replacing all the miter gate pintle
bushings with greaseless bushings. During the visit to the maintenance facility, miter
gates 110-111 were positioned on the specially designed synchrolift already painted, with
new bearing plates. New greaseless pintle bushings were installed in both miter gates.
The bushings were covered in grease because they will be stored and also floated in the
lake for 2-3 years before installation at Miraflores locks
12
Greaseless pintle bushing for Panama miter gates
Miter gate painted with coal tar epoxy – original gates rivetted construction
The lock miter gates are designed to be buoyant. They are built with watertight
construction of their lower halves (12m or 40ft) makes them buoyant in the water, greatly
reducing the working load on the pintle and anchorage. Each miter gate has an air
chamber. All gate leaves are 19.5m wide by 2.1m thick (64 ft by 7 ft). However, they
13
vary in height from 14.3m to 25m (47 to 82 ft), depending on their position. For
example, the Miraflores Locks lower chamber gates are the highest because of the
extreme variation in the Pacific tides. For repair and then installation, gates are sealed,
filled with air, floated down canal and then lifted into place.
Synchrolift facility
2.4 New Atlantic Lock – General Information. The new Atlantic lock will be a triple
lift lock. The new lock chambers will be 427 meters (1,400 feet) long by 55 meters (180
feet) wide, and 18.3 meters (60 feet) deep. The new lock will use rolling gates as opposed
to miter gates. Double gates will be place in all four lockheads for a total of eight gates to
provide for safety, operational redundancy and reliability. The operating length of the
lock chamber can be increased by opening one or two of the inner gates to provide
lenghts of 458m and 466m (1500 and 1600 ft)
The new locks on both the Atlantic side and the Pacific side will utilize water saving
basins. The water saving basins have the potential to save up to 60% of the water during
lockages. Each lock chamber will have three water-saving basins, which will reuse 60
percent of the water in each transit. There are a total of nine basins for each of the two
lock complexes. There are a total of 18 basins for the entire project. Each water-saving
basin is approximately 70 meters wide by 5.50 meters deep.
14
New Atlantic lock looking from observation platform, Gatun Lake anchorage at upper
view
15
New Atlantic lock – note rolling gates stored in lock chamber in background
New Atlantic lock - lockhead 1 or lakeside niche for rolling gate recess – there will be
two rolling gates at each end of each lock chamber
16
Looking down length of new Atlantic lock
2.5 New Rolling Gates. The final stop for the working group on Wednesday was to visit
the new rolling gate temporary storage area. The third shipment of rolling gates had just
arrived. Four gates were delivered on the postpanamax heavy lift vessel described below.
A total of 12 gates have been delivered thus far out of 16 gates total (8 for each Pacific
and Atlantic third set of locks). These are loaded and unloaded dry by use of SPMT (self
propelled moving transport).
Photo of rolling gates being off-loaded (photo from a previous shipment ahead of
working group visit) – note SPMT under and unloading gate
17
All the new locks for the Panama expansion will use rolling gates as opposed to miter
gates. This is primarily due to the large width of the locks. Rolling gates also allow for
repairs by isolating them in the niche. A rolling gate moves perpendicular (orthogonally)
across the lock to open or close. From an open position, the gate rolls from the gate
chamber or recess to the opposite gate recess. The gate moves through a channel and
“railroad” tracks in the bottom of the lock chamber and rests on carriages that guide the
weight of the gate while rolling. One unique feature of the Panama rolling gates will be
the removable lower wheel carriage. This is shown below. The new rolling gates for the
Panama locks will also be designed to be driven across.
New rolling gates will be a wheel barrow type design. In a "wheelbarrow" system, the
gate is hooked to a support structure above it. In a regular classical rolling gate, both
wagons (carriages) are placed under the gate. In a "wheelbarrow" gate, one of them is
placed under and one at the top level of the gate. The “wheelbarrow” end of the gate has
to be on the recess or pocket side of the lock chamber.
Wheelbarrow assemblyshowing upper wagon and connection - schematic
The primary advantage of the wheelbarrow gate is better stability during opening and
closing. They also offer an advantage of fewer moving parts under water. The gate
center of gravity and the resultant of residual hydraulic loads are both close to the
diagonal connecting the two wheel units. This improves the overall stability which is
important on large navigation and seaport locks. The upper wheel works in the dry and is
easier to access and maintain.
18
New rolling gates – note floating chambers in bottom
The third shipment of four gates for the new locks of the Panama Canal expansion
arrived from Italy at the Atlantic entrance of the waterway on Sunday, September 7th,
2014 . They were delivered onboard Cosco’s post-Panamax, ocean shipping vessel Xia
Zhi Yuan 6. The gates left Cimolai Shipyard, Trieste where they were built, on 17 August
before crossing the Atlantic Ocean on a 3 week journey to reach the entrance of the
Panama Canal.
Only one shipment is left to be received for all 16 gates required for the third lane locks
project. The rolling gates just delivered will be used in the new locks at the Pacific side
of the Canal. Two of the gates are 57.6 m (189 feet) long, 10 m (33 feet) wide and 31.92
m (105 feet) high, and weigh 4,163 tonnes each. These are the heaviest of the 16 rolling
gates to be used in the expanded Canal.
The other two gates just delivered are 57.6 m long, 8 m wide and 22.3 m high, and weigh
2,867 tonnes each. The construction of the gates began in October 2011 by subcontractor
Cimolai SpA. The new locks will have a total of 16 rolling gates (eight for each new lock
complex). Unlike the current locks which utilize miter gates, the expanded canal will
have rolling gates.
The first gate shipment arrived in Panama on 20 August 20, 2013 and the second on 10
June 2014. The final shipment is expected to arrive in January 2015. All gates must be in
Panama by February 2015, as agreed between the Panama Canal Authority and the
Contractor.
19
The rolling gates the working group visited were transported on board the Xia Zhi Yuan
6 heavy lift vessel. It has a Length 195.2m x Breadth 41.5m (640’ x 136’). The ship does
not fit the existing Panamax locks chamber width 33.5m (110’). However, it will fit the
new third set of locks chamber width 55m (180’). Other details of the ship:
Gross tonnage: 32,793 tons
DWT: 37,904 tons
Year of build: 2012
Builder: ZHEJIANG PENINSULA SHIP INDUSTRY - ZHOUSHAN, CHINA
Flag: CHINA
Home port: ZHOUSHAN
Rolling gates being delivered to temporary dock facility – recent shipment on September
7th 2014
Rolling gates once installed in the new lock chambers will be designed for maintenance.
The recess is designed as a “dry dock” to allow work on the gate. Supports are provided
in the recess for lifting the gate off its carriage.
20
View of transport ship Xia Zhi Yuan 6 with special support blocks
21
New rolling gate recently offloaded from the ship – tallest gate for Pacific lock
22
Rolling gates stored in temporary storage area
Lower carriage removed through opening in rolling gate
23
Lower wheel carriage for new rolling gates
2.6 Rolling Gate Machinery and Warehouse for Storing Rolling Gate Machinery
All the rolling gates are operated with a mechanical drive system that utilizes wire rope
drums at each end of the gate. The system essentially acts like a winch to either open or
close the rolling gates. The drive system includes a motor, brake, gear box, torque tubes
(drive shafts), tensioning system, and the wire rope drums. The wire rope is a continuous
loop that spools off both the bottom and top of the drum. The wire ropes attach to the
upper carriage: one directly at one side, the other via a turning wheel at the far end of the
gate chamber. The Panama Canal design wire rope drum will have redundant set of wire
ropes.
The contractor is utilizing a warehouse and indoor storage facility to store all the
mechanical and electrical equipment. The working group visited the storage facility on
Thursday. The electrical and mechanical machinery will be installed starting in early
2015.
24
Inside warehouse and storage facility
New wire rope drums in storage
25
New wire rope cables for rolling gates - 45 mm diameter
All the new locks will incorporate multiple levels of redundancy to insure they are always
operational. There will be two sets of gates at the lower end and 2 sets of gates at the
upper end for each new lock structure. This allows rehabilitation or repair of a gate while
the other gate remains operational.
26
2.7 New Pacific Lock – General Information. The working group visited the new
Pacific lock on Thursday. This will be a triple lift lock just like the new Atlantic lock.
Each new lock chamber will be 427 meters (1,400 feet) long by 55 meters (180 feet)
wide, and 18.3 meters (60 feet) deep.
The new Pacific lock will also incorporate water saving basins like the new Atlantic lock.
Both the new Pacific lock and the Atlantic lock will have a lateral culvert system that
discharges out the side of the lock walls. The locks will not fill and empty through the
floor like the current locks. The main filling and emptying culverts vary in size but are
generally 6.5 meters high by 8.3 meters wide. Hydaulic operated vertical lift gates will
be used to control flow through the culverts.
View looking down the length of the new Pacific lock upper chamber
27
New culvert for Pacific lock – secondary 6.5m high x 6.5m wide
28
Central connection for main and secondary culvert for Pacific lock
29
Inside new upper lock chamber – Pacific lock
Pacific lock – lockhead 1 rolling gate recess looking from top – rails for upper wagon
being installed and aligned
30
New rolling gate recess – Pacific lock – note hanging supports for dry docking gate
31
Pacific lock rolling gate recess – upper wagon track
2.8 Miraflores Lock. The last stop for the working group on Thursday was the
Miraflores lock. As noted earlier, this is a double lift lock with two lanes. The lock
dimensions are 33.5 m wide by 305m long (110 ft by 1000 ft). The existing Miraflores
lock utilizes buoyant miter gates.
At Miraflores Locks (and also Gatun lock), each lock chamber, except for the lower
locks, has a set of intermediate gates. The purpose of these is to conserve water by
reducing the size of the chamber, if the ship in transit is not one of the Panamax vessels it
can be accommodated by a 183m (600-ft) chamber. Because of the large size of vessels
transiting the Canal the intermediate gates are seldom used, only during extreme dry
years. The double miter gates provide operational reliability and also provide a level of
redundancy in case of damage to a miter gate.
The miter gates are hydraulic cylinder operated (direct connected) as opposed to the
original mechanical drive system discussed below. These were replaced in 1996-2004.
32
Miter Gates – Miraflores lock
Hydraulic cylinder operated miter gates – Miraflores lock
33
Double miter gates Miraflores lock
View from looking down on double set of miter gates while upper chamber is being filled
– Miraflores lock
34
Ship transiting the Miraflores lock assisted by six electrical locomotives
Note locomotive and two wire rope cables connected to ship
35
Miter gates on Miraflores lock – note collapseable handrails – handrails are collapseable
to allow the wire rope cables to pass over
Original 1914 control system in Miraflores lock showing visual water level gages, valve
and gate position indicators and operating levers
36
The original control board and electrical distribution system (by General Electric) was
still inside the Miraflores control building. This is not used but rather is left in place as a
historical artifact. Edward Schildhauer was an engineer of German immigrants who
designed most of the electrical and mechanical lock equipment. The original gate
machinery utilized a design now known as the “Panama” design.
Original gear design for moving the miter gates
The original design utilized gate struts connected to the gate and then to bull wheels
constructed within the lock walls. Each 6m (20-foot) diameter, horizontal-lying bull
wheel weighting 29 tons is geared to an electric motor. When in operation, wheel and
strut work like the driving wheel and connecting rod on a railroad locomotive to open and
close the gates.
The original locks were also all electric. Locks operations required some 1,500 electric
motors, as all controls were electrical. The General Electric Company produced about
half the electrical equipment needed during construction and virtually all of the
permanent motors, relays, switches, wiring and generating equipment. They also
supplied the original locks’ towing locomotives and all of the lighting.
Schildhauer also designed the original locks control system, though its development was
a joint effort with General Electric. All locks operation is accomplished from a control
house built on the center wall of the upper lock chamber. The original control system was
essentially a mechanical control system using motors and switches. A control board is a
37
waist-high working representation of the locks in miniature. Everything that happens in
the locks happens on the control board at precisely the same time. The switches to work
the lock gates and the other system mechanisms are located beside the representation of
that devise on the control board. To lift a huge oceangoing ship in a lock chamber, the
operator has only to turn a small chrome handle.
Another ingenious part of the system was the elaborate racks of interlocking bars
installed unseen below the control board to make the switches mechanically interlock.
Each handle must be turned in proper sequence or it will not turn. This eliminates the
possibility of doing anything out of order or forgetting a step.
All the Panama locks are now controlled by programmable logic controllers (PLC) and
video display boards. This is shown below.
Original control board at Miraflores lock
38
Original control board at Miraflores
Mechanical switches and synchronous motors under the original Miraflores control board
39
New PLC control system at Miraflores
Video display terminal at Miraflores
40
Tim Paulus
Mechanical Engineer
Saint Paul District, Corps of Engineers
and
Juan (Johnny) Wong
Third Locks Project Manager
Autoridad del Canal de Panamá
41
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The Opening of the Panama Canal
On August 15, 1914, the SS Ancon made the first official transit of the Panama Canal – traveling from ocean to ocean in under ten hours. Aboard the
steamer were dignitaries such as the President of Panama and the American ambassador, but not the chief engineer responsible for completing the
canal. Col. George W. Goethals instead traveled ahead of the Ancon via rail car, arriving at each lock to ensure everything was in order for a smooth first
passage.
George Goethals graduated second in his West Point class of 1880 and was commissioned into the Army Corps of Engineers. He began his career
building bridges, but in 1891 he took charge of completing the Muscle Shoals Canal in Alabama where he built innovative locks with an unprecedented
26-foot lift. In 1903, Goethals joined the Army’s General Staff in Washington, D.C., and quickly impressed Sec. of War William H. Taft. The War
Department had overseen Panama Canal construction since 1902, when the United States bought the French holdings there. In 1905, Taft
recommended Goethals for an assistant engineer position in Panama, but when the sitting Chief Engineer resigned, Taft instead sent Goethals as a
replacement.
Goethals arrived in Panama in 1907, just after the United States Congress passed
legislation favoring a lock canal rather than one at sea level, and his initial priority was
devising a strategy to complete the work. The canal would require the world’s largest
locks, the largest dam, creation of the world’s largest man-made lake, and it would
have to traverse the Continental Divide. Goethals needed inland waterways experts
to plan and oversee the works, so he brought in Corps of Engineers colleagues that
had experience with such projects. He placed Lt. Col. David D. Gaillard in charge of
the Culebra Cut through the Continental Divide, Lt. Col. William Sibert would complete
the locks and dam on the Atlantic side, USACE civilian Sydney B. Williamson would
complete the locks and dredging on the Pacific side, and Lt. Col. Harry F. Hodges was
responsible for the lock designs. Goethals gave his lieutenants freedom to devise their
own construction processes, instilling trust but also healthy competition amongst the
engineers. He also gave complete support to Dr. William Gorgas of the Army Medical
Corps who declared war on mosquitoes and the tropical diseases they carried to
ensure a healthy work environment.
By the summer of 1914, Goethals and his team of engineers had nearly completed
what many had believed was impossible and the United States began to celebrate
the canal. Journalists, politicians, and sightseers flocked to Panama to see the
wonder – a 32-mile, 85-foot-above-sea-level bridge of water across the continent.
The massive locks contained 4.5 million cubic yards of concrete, the earthen dam
that held back Gatun Lake was 1.5 miles long and contained 22 million cubic yards
of fill, and the 6,000 men who toiled daily in the Culebra Cut ultimately excavated
182 million cubic yards of earth. On August 15, 1914, after 7 years on the job,
George Goethals and the canal were ready for the official opening.
In front of a small crowd, the SS Ancon left Gatun at 7 a.m., and according to
passenger John Barrett, proceeded “so quietly that . . . a strange observer coming
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suddenly upon the scene would have thought that the canal had always been in
operation, and that the Ancon was only doing what thousands of other vessels must have done before her.” With Goethals ensuring that each lock and
its operators were well-prepared to meet the vessel, the Ancon steamed from Atlantic to Pacific in roughly nine hours, which still holds as the average
transit time. As John Barrett accurately observed, the canal began operation as smoothly as it would for a century to come.
To read more, please visit the History Office's full Panama Canal site here.
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Paulus, Timothy M MVP; McKinley, Brenden F LRH; MALorenzo; "[email protected]"; "IRS / Matthias
Schäfers"; "Mahrholz, Dirk (bremenports)"; "[email protected]"; "Pieter van Lierop"; "Bouwman,
Gerard (GPO)"; "Man, Wouter de (GPO)"; "AVAUX, Kris"; "[email protected]"; "John Kiernan";
"[email protected]"; "David Williams"; "[email protected]"; Schultz, Rick W. RMC; "Marc Verbeek";
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[EXTERNAL] Panama canal design (1904-1914) interesting article
Friday, September 19, 2014 3:51:39 PM
An interesting article about the design of the panama canal locks (1904-1914)
For those who visited see the paragraphs on the control board and electrical distribution system (by
general electric)
Edward Schildhauer was an engineer of german inmigrants who designed most of the electrical can
mechanical locks equipment
DESIGN OF THE LOCKS (1904-1914)
The original lock canal plan called for one three-step set of locks at Gatun, one step at Pedro Miguel
and a two-step set at Sosa Hill. In late 1907, it was decided to move the Sosa Hill locks further inland
to Miraflores, mostly because the new site provided a more stable construction foundation, but also
because it afforded greater protection against sea bombardment.
The locks took their names from geographic names already in common use before the Canal was built. All lock chambers have the same 110 by 1,000 feet dimensions, and they are built in pairs. That is, two
lanes of chambers run side by side to accommodate two lanes of traffic, either in opposite directions at
the same time or in the same direction, depending on transit needs. Gatun Locks consists of three
steps or pairs of chambers, there is one step at Pedro Miguel and two at Miraflores, making six pairs, 12
chambers in all. The locks have been called the structural triumph of the Panama Canal and are a
unique aspect of the waterway. At the time of their construction, their overall mass, dimensions and
innovative design surpassed any similar existing structures, and they are still considered to be an
engineering wonder of the world.
It took four years to build all of the locks from the first concrete being laid at Gatun on August 24,
1909. Until the late 1800s, concrete, a combination of sand, gravel and cement, had been little used in
building, and then mostly for floors and basements. There was still a great deal to be learned and
numerous decisions to be made in the science of concrete which requires specific, controlled
measurements of water/cement/sand ratios and aggregate size, as well as careful timing of a
streamlined delivery system from source to site. The concrete work in Panama was an unprecedented
challenge that would not be equaled in total volume until construction of Boulder Dam in the 1930s.
In spite of the newness of the science, the results were extraordinary. After more than 80 years of
service, the concrete of the Panama Canal locks and spillways is in near perfect condition, which to
present-day engineers is among the most exceptional aspects of the entire Canal.
Canal organization ships, the Ancon and the Cristobal, brought all of the cement to build the locks,
dams and spillways from New York. On the Atlantic side, gravel and sand came by water from areas
east of Colon, the gravel from a large crushing plant in Portobelo and the sand from Nombre de Dios. For the Pacific side, rock was quarried and crushed at Ancon Hill; the sand came from Punta Chame in
Panama Bay.
Three men, Lieutenant Colonel Harry Hodges, Edward Schildhauer and Henry Goldmark, were largely
responsible for the engineering design of the locks. The work took years of advanced planning. Hodges
was an Army officer and an invaluable assistant to Goethals, had overall responsibility for the design
and construction of the lock gates, arguably the most difficult technical responsibility of the entire
project. Goethals was to state that the Canal could not have been built without Hodges. Schildhauer
was an electrical engineer and Goldmark was in charge of lock gate design.
The key factor in the whole Canal enterprise, of course, was, and is, water. Water lifts ships 85 feet
above sea level to the surface of Gatun Lake, floats them across the Continental Divide and lowers
them again to sea level in the opposite ocean. Water also serves to generate electrical power for the
Canal to run the electric motors that open and close the gates and valves and the electric locks
locomotives.
No pumps are used at the Panama Canal, the water does its work by force of gravity alone. Water is
admitted or released through giant tunnels, or culverts, eighteen feet in diameter, running lengthwise
within the center and side walls of the locks. Branching off at right angles to these culverts, smaller
culverts run laterally under the floor of each lock chamber, 20 to each chamber. Each cross culvert has
five openings for a total of 100 holes in each chamber for the water to enter or drain, depending on
which valves are opened or closed. This large number of holes distributes the water evenly over the full
floor area to control turbulence
To fill a lock, the main valves at the lower end of the chamber are closed, while those at the upper end
are opened. The water pours from the lake through the large culverts into the cross culverts and up
through the holes in the chamber floor. To release the water from the lock, the valves at the upper end
are closed, while those at the lower end are opened.
The lock gates, or miter gates as they are known because they close in a wide V, are the Canal's most
dramatic moving parts. The gates swing like double doors. The hollow, watertight construction of their
lower halves makes them buoyant in the water, greatly reducing the working load on their hinges. All
gate leaves are 64 feet wide by 7 feet thick. However, they vary in height from 47 to 82 feet,
depending on their position. For example, the Miraflores Locks lower chamber gates are the highest
because of the extreme variation in the Pacific tides.
The design and manufacture of all of the lock gates was one of the Canal's great engineering
challenges and one of its greatest triumphs. The simple, yet powerful gate operating mechanism was
designed by Edward Schildhauer. In its design he had no established model to go by. Yet every aspect
of this critical mechanism had to be precision engineered and manufactured to work flawlessly and
dependably. The gates had to swing easily, yet withstand enormous pressures. To operate, the lock
gates leaves are connected by steel arms, called "struts," to huge bull wheels constructed within the
lock walls. Each 20-foot-diameter, horizontal-lying bull wheel is geared to an electric motor. When in
operation, wheel and strut work like the driving wheel and connecting rod on a railroad locomotive to
open and close the gates.
At Miraflores Locks, each lock chamber, except for the lower locks, has a set of intermediate gates. The
purpose of these is to conserve water by reducing the size of the chamber, if the ship in transit is not
one of the Panamax giants and be accommodated by a 600-foot chamber.
As the lock gates themselves are a form of dam and above sea level, precautions were taken to protect
them from damage that could allow the lake water to escape and flow out to sea. One measure was to
have double gates ahead of the vessel, an operating gate and a guard gate, at points where damage to
a gate could join the two levels, that is, at the upper and lower ends of the upper lock in each flight
and at both ends of the Pedro Miguel single-step lock.
Also, iron fender chains were installed to stretch across the chambers between the lock walls to protect
the guard gates. Only after the ship was in proper position and under towing locomotive control was
the chain lowered. The idea was that if a ship went out of control and struck the chain, an automatic
release would let the chain out slowly until the ship came to a stop, thus limiting possible damage. The
expense of their upkeep against the extreme unlikelihood of their use caused the Board of Directors to
approve fender chain removal in July 1976, except at the upper ends of Gatun and Pedro Miguel locks;
these remaining chains were removed in October 1980.
Yet another devise stood as safeguard should a ship break through a guard gate. That was what was
called an emergency dam installed on the side walls at the entrance of each upper lock between the
fender chain and the guard gates. It a big steel apparatus mounted to swing across the lock entrance
in about two minutes in case of emergency. A series of wicket girders would descend forming runways
down which huge steel plates would be dropped until the channel was sealed off. Never put to use, the
emergency dams were removed in the mid 1950s.
Electricity was the power that ran Canal construction-era cableways, cranes, rock crushers and cement
mixers. An all-electric canal was an innovation in the first decade of the 20th century. Locks operations
required some 1,500 electric motors, as all controls were electrical. The General Electric Company
produced about half the electrical equipment needed during construction and virtually all of the
permanent motors, relays, switches, wiring and generating equipment. They also built the original locks
towing locomotives and all of the lighting.
The electric towing locomotive system was designed to provide complete control over the movement of
vessels transiting the locks. Designed by Schildhauer, the locomotives work on track built atop the lock
walls operating at a speed of about 2 miles per hour. An important design factor was that they have to
travel the 45-degree incline between the lock chambers. The locomotives were built in Schenectady,
New York, at a unit cost of $13,000.
Schildhauer also designed the basic concept of the locks control system, though its development was a
joint effort with General Electric. All locks operation is accomplished from a control house built on the
center wall of the upper lock chamber. Here, from an unobstructed view of the entire locks flight and a
cleverly designed control board, a single person can run every operation in the passage of a ship,
except towing locomotive movement.
A control board is a waist-high working representation of the locks in miniature. Everything that
happens in the locks happens on the control board at precisely the same time. The switches to work
the lock gates and the other system mechanisms are located beside the representation of that devise
on the control board. To lift a huge oceangoing ship in a lock chamber, the operator has only to turn a
small chrome handle.
Another ingenious part of the system are elaborate racks of interlocking bars installed unseen below the
control board to make the switches mechanically interlock. Each handle must be turned in proper
sequence or it will not turn. This eliminates the possibility of doing anything out of order or forgetting a
step.
Only in an electrically run system could the locks have been controlled from a central point. An
individual motor in the system can be located as much as half a mile away from the control board. This
same system has been in use virtually unchanged for more than eight decades, and it still works
perfectly.
The Pacific-side locks were finished first, the single flight at Pedro Miguel second in 1911 and Miraflores
in May of 1913. Exceptionally high morale permeated the entire work force at this time. On May 20,
1913, shovels No. 222 and No. 230, which had been slowly narrowing the gap in Culebra Cut, met "on
the bottom of the Canal." At 40 feet above sea level, the Cut had reached its full construction-era
depth. Guard gates at Gatun performed flawlessly the second week of June 1913, and on June 27, the
last of the Gatun Dam spillway gates was closed, allowing the lake to now rise to full height. Dry
excavation ended three months later. When a January 1913 slide at Cucaracha spilled 2,000,000 cubic
yards of earth into the Cut, it was decided to flood the Cut and finish the clearing by dredge. The last
steam shovel lifted the last rock in the cut on the morning of September 10, 1913, to be hauled out on
the last dirt train by locomotive No. 260.
The seagoing tug Gatun, an Atlantic entrance working tug used for hauling barges, had the honor on
September 26, 1913, of making the first trial lockage of Gatun Locks. The lockage went perfectly,
although all valves were controlled manually since the central control board was still not ready.
As if to further test the system, an earthquake struck on September 30, knocking seismograph needles
off the scale at Ancon. Although there were landslides in the interior and cracked walls in some
Panama City buildings, Gorgas reported to Washington that "There has been no damage whatever to
any part of the Canal."
Six big pipes in the earthen dike at Gamboa flooded Culebra Cut that same week. Then, on October 10,
1913, President Woodrow Wilson pressed a button in Washington and relayed by telegraph from
Washington to New York to Galveston to Panama the signal that blew the center of the dike to
complete the flooding of the Cut and join it to Gatun Lake.
Dredges, tugs, barges and crane boats that had been laboring in the sea level approaches of the Canal
and in the two terminal bays, much of it left behind by the French, was now brought in to clear the
Cut. Barges dumped the spoil in designated areas of Gatun Lake, all in the manner that Philippe BunauVarilla had long ago said it should be done. Floodlights installed in the Cut allowed around the clock
work. The old French ladder dredge Marmot made the "pioneer cut" through the Cucaracha slide on
December 10, 1913, to open the channel for the first time.