Download - Helvetas Nepal Trail bridge experience

Trail Bridge Experience in Nepal

S.C. KanthaTeam Leader

Trail Bridge Support Unit

Tunis, 11 Oct. 2010

HELVETAS

GREETINGS FROM NEPAL –LAND OF THE HIMALAYAS

Title of Presentation. Place, DD.Month.YYYYHELVETAS

Nepal a Land locked country situated between 2 Giant Countries China and India.

Nepal in Asia


• Area 147,181 km2• Population 28

million• Within 170 km from

almost sea level to 8,848 m

• Per capita GDP US $ 450

Country Background


• 75 districts, 4000 VDCs and 50,000 settlements

• World’s Steepest Slope

• World’s youngest geology

Country Background


• Landslides and road blockage very common, particularly during monsoon

• Most diverse climate–Terai : 48oC–Himalayas : 35oC (-ve)

• 80 % of land : Hills and Mountains

• Rain : as high as 1,350 mm per year

Country Background


• 6,000 rivers and rivulets and most of them turbulent

• Drainage density 0.3 per square km

• Annual discharge of water 2 billion Cum.

• Road density 14 km per 100 km2

• One road bridge needed at every 5.5km

Country Background


• 4,000 pedestrian bridges are built

• Potential demand of 6,000 bridges

• Average beneficiary per bridge is 2,500

• Per capita bridge cost US $ 10

• Design life of a bridge 50 years

Country Background


• A country of diversified ethnicity, castes, cultures, religions and languages

• Road construction very challenging because of geology and a very costly affair

Country Background


• 70% of population does not have access to roads

• The only reliable means of transport is pedestrian bridges

Country Background


• One to two weeks non-stop walk not an exception

• Sometimes no access for months, particularly during monsoon

Country Background


• Access to basic services-health post, post office, market, school not guaranteed

• Lives particularly of children and women endangered

• Foot bridge totally change the lives of people

Country Background


• Pedestrian bridge is a must for crossing rivers and having uninterrupted movement

• Pedestrian bridges are the safe and improved means of river crossings

Country Background


• It is a very low cost project, built in a comparatively short period and benefiting the poor and the rural communities

Country Background


• For centuries people traditional means of river crossings using local know-how

• Early 20th century, Rana Rulers built modern bridges

Evolution of Pedestrian Bridges


1960s• Based on Swiss

Geologist Advice• Unlock the interior• Govt. decided to

promote pedestrian bridges

• Suspension Bridge Division established in1964



1970s• Swiss support

available for the program

• Standardization of designs



1970s• Preparation of

technical manuals – survey, design, standard drawings and construction

• Workshops established for fabrication of steel parts for bridges



1980s• Withdrawal of Swiss

experts• Huge bridge demand

from people• Difficulties to select

the most needy ones



1980s• Study of foot trails in

the hill and mountainous districts

• Preparation of main trail maps and service centre maps

• Important trails identified



1990s• Steel decks instead of

wooden planks• Turnkey modality

applied for contracting construction works

• Huge demands for bridges on local trail

• SBD - construction of bridges on main trails



1990s• Helvetas initiated

construction of bridges on local trails under community approach

• Local bridge building technology upgraded with engineering input



1990s• SDC provided funds

for Community Bridges

• Bridge outputs increased tremendously



2000s• Demarcation Policy

applied – SSTB & LSTB

• Technical Manuals for SSTB bridges developed



2000s• National Trail Bridge

Policy effective• Prioritization criteria

established• WB, ADB and DFID

funds in addition to SDC available



• Capacity building through EIs

• Course Manuals for practitioners (Eng, Sub Eng, Asst Sub Eng) developed

• Trail Bridge course incorporated in the curriculum for engineers



•Trail Bridge sub-sector concept emerged

•Sector-wide Approach introduced

•Basket funds established

• GoN, SDC, WB and DFID to provide funds in the Basket Fund



• ADB to provide funds through DRILP and RRRSDP

• TBSU/Helvetas to provide Technical Assistance on behalf of the SDC



• TB SWAp implemented since July 2009

• Five year Phase up to July 2014

• Target – NC 2200, MM of 500, and RM of 4,000 bridges annually and access trail improvement of 750 km

• Budget of US $ 72 million for 5 years



• Technical assistance budget of US $ 8 million for 5 years

• Technical Assistance to Bhutan, Tanzania, Ethiopia, Indonesia, Honduras,

• SSTB bridge under community approach and LSTB under contracting modality



• Bridge building know-how at community level - DMBT

• Employment at local level of 2,500 person days



• Bridge Technology

In terms of span

Short Span Trail Bridge (SSTB) : for span up to 120m.

Long Span Trail Bridge (LSTB) : for span > 120m

Technology


Bridge type

SuspendeD type -D-type SuspensioN type - N-type


Technology

Standard Design• -16m• - 20m• - 24m• - 28m• - 32m

Steel Truss for span up to 32m


The selection of the D-type or N-type depends mainly on the topography of the bridge site.

Technology


suitable for hills and sloped topography. this type of bridge is selected where the bridge

foundations can be placed at sufficiently high position giving required free board from the highest flood level.

is more economic, simple to design and construct than other bridge types.

applicable in 85% cases.

Applicability of D-type Bridge


suitable for plane and flat topography. this type of bridge is selected only when the Suspended

type bridge is no more feasible due to insufficient free board.

this bridge is more expensive and more complex in survey, design and construction than the Suspended type bridge.

only applicable in 15% cases.

Applicability of N-type Bridge

SSTB D-type Bridge Technology technology is based on maximum use of local materials maximum use of local skills only use of simple hand tools constructed by the community engineering within the capacity of asst.

sub-engineers

Technology

LSTB D-type Bridge Technology technology is more complex & expensive than

SSTB constructed at only socio-economically

feasible sites. engineering through Pvt. Consultants,

construction through contractors.

Technology


Cable Setting


Walkway

Fitting

Technology

Walkway Fitting


Tower ErectionTechnology


Cable Pulling : A critical Milestone

Technology


Cable HoistingTechnology


Suspender fitting

Technology


Wind guy System

Technology


Tools for Construction and Bridge Erection

Technology


Technology

•Short Span Trail Bridge Standard Technical Handbook for Suspended Type, Vol. I, II and III (2003) - SSTB D-type

•Short Span Trail Bridge Standard Technical Handbook for Suspension Type, Vol. I, II and III (2003) -SSTB N-type

•Long Span Trail Bridge Manual•Vol. A: Design (2004)•Vol. B: Survey (1983)•Vol. C: Standard Drawings (2004) •Vol. D: Construction (1990)

•Steel Truss Bridge Manual•Quality Control Manual •Demonstration Model Bridge Training Manual (2004) DMBT

Tech

nica

l Man

uals


Technology

•Social Organizational Support Manual

Soci

al M

anua

ls

•Manual for Consulting Service (2004)•Manual for Contractors (2005)

Man

ager

ial M

anua

ls


Technology

•Training Course Manual for on Trail Bridges for Practitioner Engineers (2003)

•Training Course Manual on Trail Bridges for Practitioning Overseers (2003)

•Training Course Manual on Trail Bridges for Practitioning Sub-Overseers (2003)

•Course Manual on Trail Bridges for Bachelor of Civil Engineering (2003)

•Course Manual on Trail Bridges for Diploma in Civil Engineering (2003)

•Course Manual on Trail Bridges for Sub-Overseers (2003)

• Tra

inin

g Co

urse

Man

uals


Technology

• Trail Bridge Strategy • Trail Bridge Directives• Guidelines on Public Hearing, Public Review and Public

Audit• Guidelines on NGOs Mobilization • Guidelines on Budget and Procurement Plan• Guidelines on Physical Progress and Expenses Reporting

Polic

ies

and

Gui

delin

es


•Bridge building know-how at community level - DMBT

•Employment at local level of 2,500 person days

Technology


A community built bridge


Local communities working at construction site


Maintaining transparency through public hearing/review/audit

Download - Helvetas Nepal Trail bridge experience

Top Related