BCRRA Conference
Trondheim, Norway
June 25-27, 2013
WORK SHOP 1 - PAVEMENT DESIGN
IN COLD REGIONS
Joel D. Ulring, P.E.
Golder Associated Inc.
Anchorage, Alaska USA
June 24, 2013
ORDER OF PRESENTATION

Introduction

Anchorage Facts

Municipality of Anchorage Pavement Design
Practice

State of Alaska Pavement Design Practice

Summary
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INTRODUCTION
Joel D. Ulring P.E.
Senior Geotechnical Engineer
Golder Associates Inc.
Anchorage Alaska

18 Years Public Service in Minnesota Counties

10 Years as Geotechnical Engineer Consultant
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3
ANCHORAGE FACTS
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4
ANCHORAGE FACTS
Anchorage
Area Map
 Population

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- Alaska
790,000
- Anchorage
300,000
Significant
Growth in
1970’s
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ANCHORAGE FACTS
Anchorage Facts




61° North Latitude
Design Thawing Index
Air = 4000 °Days
Surface = 3200 °Days
Design Freezing Index
Air = 3200 °Days
Surface = 6800 °Days
Typical Frost Penetration
Depth 9 feet (2.75 m)
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ANCHORAGE PAVEMENT DESIGN
Municipality
of
Anchorage
Pavement
Design
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ANCHORAGE PAVEMENT DESIGN
MOA Design Criteria Manual – Chapter 1 Streets

Section 1.10 Road Structural Fill Design

Primary Design Objectives
 Reduce
 Obtain
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freezing and thawing impacts on road
roadway/Pavement design life
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ANCHORAGE PAVEMENT DESIGN
MOA Design Criteria Manual – Chapter 1 Streets

Section 1.10 Road Structural Fill Design

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Mandatory Design Objectives
 Mitigate
the formation of ice lenses
 Prevent
pumping of subgrade
 Prevent
differential frost heave
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ANCHORGAE PAVEMENT DESIGN
Differential Frost
Heaving of Insulated
Pavement Section
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ANCHORAGE PAVEMENT DESIGN
PAVEMENT DESIGN PROCESS

Subsurface Soil Investigation (1 borehole ≈ 300 ft.)

Laboratory Testing of Collected Soil Samples

Soil Frost Group Index Determined
Frost Group: NFS, F1, F2, F3, F4

Thermal Analysis (Berg2)

Design Pavement Section
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ANCHORAGE PAVEMENT DESIGN
MOA Frost Group
Soil Classification
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ANCHORAGE PAVEMENT DESIGN
Typical Soil Types
of
Anchorage
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ANCHORAGE PAVEMENT DESIGN
MOA Design Criteria Manual – Chapter 1 Streets

Section 1.10 Road Structural Design Methods
 Minimum Section

Complete Protection Method
 Excavate
and replace frost susceptible soils with non frost
susceptible soil (NFS)

Limited Subgrade Frost Penetration Method
 Allows
frost penetration of 10% into subgrade based on
thickness of structural section
Provision for use of rigid board insulation to reduce
structural section thickness.
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ANCHORAGE PAVEMENT DESIGN
Minimum Structural Section
NFS Soil Subgrade
2” AC
2” Leveling Course
6” Type II-a Fill
12” Type II Fill
Subgrade
(F1 Soils)
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ANCHORAGE PAVEMENT DESIGN
Complete Protection Method
Typical Pavement Structural Section
2” AC
2” Leveling Course
18” Type II-a Fill
2” Board Insulation
Type II Fill 24”- 30”
Calculated Frost Depth
Subgrade
(F2, F3 or F4 Soils)
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ANCHORAGE PAVEMENT DESIGN
Limited Subgrade Frost Penetration Method
Typical Pavement Structural Section
2” AC
2” Leveling Course
18” Type II-a Fill
2” Board Insulation
Type II Fill 18”- 26”
10% Frost Penetration
Calculated Frost Depth
Subgrade
(F2, F3 or F4 Soils)
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ANCHORAGE PAVEMENT DESIGN
TYPICAL STREET DESIGN SECTION
Limited Subgrade Frost Penetration Method
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ANCHORAGE PAVEMENT DESIGN
LEVELING COURSE GRADATION
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ANCHORAGE PAVEMENT DESIGN
CLASSIFIED FILL GRADATIONS
Type II
U.S. Std. Sieve
Cumulative %
Passing by Weight
8“
100
3“
70-100
1-1/2“ 55-100
3/4“
45-85
#4
20-60
#10
12-50
#40
4-30
#200
2-6
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Type II-a
U.S. Std. Sieve
Cumulative %
Passing by Weight
3“
100
3/4“
50-100
#4
25-60
#10
15-50
#40
4-30
#200
2-6
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ANCHORAGE PAVEMENT DESIGN
COMMENTS

How should current climate trends be accounted for in
design?

Should design parameters (Freezing & Thawing Indices)
within Berg2 analysis be adjusted?

Should another thermal analysis model be considered?

MOA is currently reviewing their pavement design
manual.
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THANK YOU !
QUESTIONS ?