Halsema Highway

CONFIDENTIAL PRIVATE INFORMATION

International Forum on Life-Cycle Maintenance and Management

Technologies for Smart Highway System

2

Highway Challenges

A Holistic Approach to Road Construction and Environmental Impact, and the Role of Ecologically Based Techniques in Planning and Design

Authors: Steven B Finnie and Harold T M Insley

• Steven B Finnie

Associate Director, Pavement, Trackbed and Materials Consultancy

URS Scott Wilson Ltd, Nottingham, United Kingdom

• Harold T M Insley

Associate Director, Head of Environmental Services

URS Scott Wilson, Hong Kong


Contents of Presentation

• Halsema Highway Case Study

• Typical Slope Problems

• Design of Remedial Works

• Environmental Aspects

• Examples of other Mountain Road Projects

• Typical Design Features

3

Highway Challenges

Theme of paper: Mountain Highways in Developing

Countries

Halsema Highway History

4

Highway Challenges

• Road at 2,000m elevation and above

• Typical rainfall 2,400mm per year

• Partially paved mountain road damaged by earthquake and typhoons in1990s

• Richter 7.8 magnitude quake in July 1990 seriously damaged road, and Hyatt Hotel in Baguio collapsed killing 80 people

• Damage to road not immediately repaired

• Significant typhoons caused major erosion damage

• Consultants appointed in 1996 for feasibility study to rehabilitate highway

• World Bank funded


Major Arterial Highway serving Region

5

Highway Challenges

• Halsema Highway runs from Baguio City to Bontoc to Banaue (rice terraces)

• Baguio City regional capital

• Major vegetable growing area

• Vegetables trucked down to outskirts of Baguio in small trucks

• Transferred to 10 wheeler trucks or bigger for transport to Manila (capital city)

• Construction on first section from La Trinidad to Mount Data started in 2000

Feasibility Study, Rehabilitation Design and Construction Supervision

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Highway Challenges

• 180 km long Halsema Highway links Philippines summer capital of Baguio with famous “ Banaue rice terraces” World Heritage Site considered to be more than 2,000 years old

• Road crosses some of most difficult topography in South East Asia – main ridge of Central Cordillera runs approximately north-south

• Central Cordillera: steep, knife-edged and underlain by highly fractured, faulted and weathered materials

• Scott Wilson carried out feasibility study, design and construction supervision of geotechnical works

• Scope of services included geotechnical, geological, bio-engineering, hydrological, environmental, ecological and social impact aspects


Halsema Highway, Philippines

7

Highway Challenges

• Rural highway in high rainfall, seismically active mountainous

area

• Carried out feasibility study for rehabilitation including geotechnical, hydrological,

environmental and social impact investigations

• Although Halsema Highway is a major road, it is classed as a “low-cost” road for purposes of this

rehabilitation, which restricted scope of investigations (i.e. limited ground investigation) and scope of rehabilitation work

Halsema Highway, Philippines

8

Highway Challenges

• Landscape very fragile, and highly

susceptible to erosion caused by intense storm runoff and destabilising earthquakes

• Programme of aerial photography

carried out

• Followed by field mapping, engineering geological inspection and the sinking of boreholes

• Initial Environmental Assessment carried out

• Innovative bio-engineering designs

needed to stabilise slopes


One of “Most Dangerous Roads in World”

9

Highway Challenges

Typical Slope Problems

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Highway Challenges

• Failure of slopes on to road (rock falls, debris slides etc)

• Failure of slopes below road

Leading to loss of road edge

(including wall foundation failure)

• Failure of entire road formation

• Debris flows & slope erosion

Technical Assistance for Risk Assessment and Management D2

282800 in 1997


Large Landslide below Highway

11

Highway Challenges

Unstable Slopes above Highway

12

Highway Challenges


“Temporary” Structures to Maintain Access

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Highway Challenges

• After earthquake and typhoons in 1990s access along highway provided with mixture of “temporary measures”including Bailey Bridges, and temporary diversions

• Photo of crossing of “saddle” where roadway failed on both sides of highway

Design of Remedial Measures

14

Highway Challenges

Integrated Approach Required

•Geotechnical engineering measures

•Drainage engineering measures and erosion control

•Slope protection and bio-engineering measures

•Environmental protection


Typical Rehabilitation

15

Highway Challenges

Halsema Highway

Typical Major Rehabilitation

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Highway Challenges

Halsema Highway


Integration of Bio-Engineering with Geotechnical Design

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Highway Challenges

Failures and Erosion below Road Bench

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Highway Challenges

Pre-Construction


Rehabilitation below Road Bench

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Highway Challenges

Works Substantially Complete

Masonry Wall to Support Road Bench

20

Highway Challenges


Drainage and Stream Protection Measures

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Highway Challenges

Above Road Retaining Structure

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Highway Challenges

Completion of shotcrete &

construction of above-road

retaining structures


Environmental Aspects

23

Highway Challenges

• Environmental Impacts related to Heritage Sites and National Park

• Construction Impacts

• Traffic Related Impacts

• Social Impacts

Environmental Impacts – Heritage Sites and National Park

24

Highway Challenges

• Photo shows rice terraces near Banaue

• Heritage site

• Road also passes through National Park

• World Bank required impacts on Heritage Site and National Park minimised as far as practical


Construction Impacts

25

Highway Challenges

• Noise (generated by construction plant)

• Dust

• Disposal of excavated material

• Excavation of borrow areas

• Water quality impacts, and erosion

• Social impacts from clearance, etc.

• Impact of construction on traffic using road

Traffic Related Impacts

26

Highway Challenges

• Improved road surface, previously unpaved, now concrete pavement, results in increased vehicle speeds

• Increased speeds result in greater potential for accidents involving excessive speeds

• Accidents as a result of “blind” corners, pedestrians on roads, boulders from slopes above causing obstacle on road, fog banks

• Mountain road creates opportunity for major accidents with vehicles crashing off road, and causing many fatalities (especially buses)

• Limited budget for road side barrier but small up stand wall included

• Road humps to reduce speed

• Increased axle loads


Social Impact Assessment

27

Highway Challenges

• Clearance of encroachments into road reserve

• Some acquisition of agricultural land for minor alignment improvements

• Socio-Economic Surveys carried out

• Resettlement Action Plan prepared

• Community engagement

Examples of Other Mountain Road Projects

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Highway Challenges

• Nepal: Prithvi Highway

• Nepal: Third Road Improvement Project

• Tajikistan: Shagon-Zigar Road

• Bhutan: Road Network Study

• Ethiopia: Koombolcha – Mekane Salem – GundewienRoad


Prithvi Highway, Nepal

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Highway Challenges

Flood Damage Assessment, Study Report, Design of

Remedial Works and Supervision

• Geotechnical examination, inventory of flood damage

• Recommendations for and prioritisation of reinstatement and further erosion protection

works

• Remedial, reinstatement, and protection measures

• Design/supervision/ contract

management services for damage repair, contract management and supervision

Third Road Improvement Project, Nepal

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Highway Challenges

• Improvement and rehabilitation

of 350km of rural access road to

bitumen standard in mountainous

and flat terrain

• Economic screening study

• Typical design details, and

design checks

• Procurement and construction

supervision

Improvement and Rehabilitation of Rural

Roads


Shagon-Zigar Road, Tajikistan

31

Highway Challenges

• Situated along border with Afghanistan,

alignment through foothills of Pamirs and

bordered by Pyanj River to east

• Alignment traverses extremely rugged,

mountainous terrain

• Challenges to engineering team included

rockfall from natural slopes, extreme

topography and weather conditions and

sensitive ground conditions disturbed by

pre-contract blasting and seismic activity

Feasibility, Design, Supervision

Road Network Study, Bhutan

32

Highway Challenges

• Survey and analysis of typical slope

stability problems

• Slope maintenance manual

• Economic evaluation of proposed

improvements

• Environmental Impact Assessment

of proposed improvements

• Road improvement strategies

Technical Assistance Project to Prepare Prioritised Road

Improvement Programme


Kombolcha – Mekane Salem – Gundewien Road, Ethiopia

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Highway Challenges

• Construction of 136 km new gravel road,

with dense base macadam on steep

gradients, and simultaneous construction

of 2 new bridges over River Nile and

tributary, Difarsa River

• Geotechnical services included detailed

aerial photograph interpretation, field

engineering geological and

geomorphological mapping, reference

condition mapping, landscape evolution

modelling, ground investigation and

outline design of slope works.

Remote Sensing, Engineering Geological Mapping, Ground

Investigation, Design Review (including redesign) and

Construction Supervision

Typical Design Features

34

Highway Challenges

• Bio-engineering

• Gabion Wall

• Combined Masonry and Gabion Wall

• Reinforced Earth Wall

• Reinforced Concrete Grid Wall

• Surface Reinforcement

• Buttress Wall


Bio-Engineering Slope Protection

35

Highway Challenges

Bio-engineering is the use of vegetation, either alone or in conjunction with civil

engineering structures, to reduce slope instability and erosion on slopes.

4 main groups of techniques are available:

� Grass line planting

� Brush layering etc

� Shrub, tree and bamboo

planting

� Composite techniques

Bio-engineering

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Highway Challenges

• Low construction cost

• Low maintenance cost

• Visually preferable

• Contributes to local economy

• Species selection is key:

• Hardy

• High rainfall and drought resistant

• Extensive use of grasses

• Bamboo and Shrub species with strong root network

• Pine trees

• Pilot trials

• Indigenous and imported species

• Local expertise utilised


Gabion Wall

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Highway Challenges

Above Road: Gabion Wall in Nepal

Below Road: Gabion Wall in Ethiopia

Combined Masonry and Gabion Wall

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Highway Challenges

Pre-Construction

Construction Substantially Complete


Reinforced Earth Wall

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Highway Challenges

Under construction

(Ethiopia)

Reinforced Earth Wall

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Highway Challenges

Completed wall (Ethiopia)


Reinforced Concrete Grid Wall

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Highway Challenges

Reinforced Concrete Grid Wall comprising Reinforced Concrete Members with Mortared Masonry Panels on Halsema Highway

Surface Reinforcement

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Highway Challenges

“Plastering” a thin concrete layer over decomposed rock slope in Laos


Buttress Wall

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Highway Challenges

Buttress wall under construction in Sri Lanka

Documents

Halsema Highway