helvetas nepal trail bridge experience
Post on 06-May-2015
Embed Size (px)
DESCRIPTIONPresentation ADB Tunis
- 1.S.C. Kantha Team Leader Trail Bridge Support Unit Tunis, 11 Oct.2010 HELVETAS GREETINGS FROM NEPAL LAND OF THE HIMALAYAS Trail Bridge Experience in Nepal
2. Nepal in Asia Nepal a Land locked country situated between 2 Giant Countries China and India. 3.
- Area 147,181 km2
- Population 28 million
- Within 170 km from almost sea levelto 8,848 m
- Per capita GDP US $ 450
Country Background 4.
- 75 districts, 4000 VDCs and 50,000 settlements
- Worlds Steepest Slope
- Worlds youngest geology
Country Background 5.
- Landslides and road blockage very common, particularly during monsoon
- Most diverse climate
- Terai : 48 o C
- Himalayas : 35 o C (-ve)
- 80 % of land : Hills and Mountains
- Rain : as high as 1,350 mm per year
Country Background 6.
- 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 km 2
- One road bridge needed at every 5.5 km
Country Background 7.
- 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 8.
- A country of diversified ethnicity, castes, cultures, religions and languages
- Road construction very challenging because of geology and a very costly affair
Country Background 9.
- 70% of population does not have access to roads
- The only reliable means of transport is pedestrian bridges
Country Background 10.
- One to two weeks non-stop walk not an exception
- Sometimes no access for months, particularly during monsoon
Country Background 11.
- Access to basic services-health post, post office, market, school not guaranteed
- Lives particularly of children and women endangered
- Foot bridge totallychange the lives of people
Country Background 12.
- Pedestrian bridge is a must for crossing riversand having uninterrupted movement
- Pedestrian bridges are the safe and improved means of river crossings
Country Background 13.
- It is a very low cost project, built in a comparatively short period and benefiting the poor and the rural communities
Country Background 14.
- For centuries people traditional means of river crossings using local know-how
- Early 20th century, Rana Rulers built modern bridges
Evolution of Pedestrian Bridges 15.
- Based on Swiss Geologist Advice
- Unlock the interior
- Govt. decided to promote pedestrian bridges
- Suspension Bridge Division established in1964
Evolution of Pedestrian Bridges 16.
- Swiss support available for the program
- Standardization of designs
Evolution of Pedestrian Bridges 17.
- Preparation of technical manuals survey, design, standard drawings and construction
- Workshops established for fabrication of steel parts for bridges
Evolution of Pedestrian Bridges 18.
- Withdrawal of Swiss experts
- Huge bridge demand from people
- Difficulties to select the most needy ones
Evolution of Pedestrian Bridges 19.
- Study of foot trails in the hill and mountainous districts
- Preparation of main trail maps and service centre maps
- Important trails identified
Evolution of Pedestrian Bridges 20.
- 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
Evolution of Pedestrian Bridges 21.
- Helvetas initiated construction of bridges on local trails under community approach
- Local bridge building technology upgraded with engineering input
Evolution of Pedestrian Bridges 22.
- SDC provided funds for Community Bridges
- Bridge outputs increased tremendously
Evolution of Pedestrian Bridges 23.
- Demarcation Policy applied SSTB & LSTB
- Technical Manuals for SSTB bridges developed
Evolution of Pedestrian Bridges 24.
- National Trail Bridge Policy effective
- Prioritization criteria established
- WB, ADB and DFID funds in addition to SDC available
Evolution of Pedestrian Bridges 25.
- Capacity building through EIs
- Course Manuals for practitioners (Eng, Sub Eng, Asst Sub Eng) developed
- Trail Bridge course incorporated in the curriculum for engineers
Evolution of Pedestrian Bridges 26.
- 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
Evolution of Pedestrian Bridges 27.
- ADB to provide funds through DRILP and RRRSDP
- TBSU/Helvetas to provide Technical Assistance on behalf of the SDC
Evolution of Pedestrian Bridges 28.
- 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
Evolution of Pedestrian Bridges 29.
- 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
Evolution of Pedestrian Bridges 30.
- Bridge building know-how at community level - DMBT
- Employment at local level of 2,500 person days
Evolution of Pedestrian Bridges 31.
- Bridge Technology
- In terms of span
- Short Span Trail Bridge (SSTB) : for span up to120m.
- Long Span Trail Bridge (LSTB) : for span > 120m
- Bridge type
SuspendeD type -D-type SuspensioN type - N-type 33.
- Standard Design
- - 20m
- - 24m
- - 28m
- - 32m
Steel Truss for span up to 32m 34.
- The selection of the D-type or N-type dependsmainly on the topography of the bridge site.
- 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 36.
- suitable for plane and flat topography.
- this type of bridge is selected only when theSuspended type bridge is no more feasible due to insufficient free board.
- thisbridge 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 37.
- 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
- 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 39. Cable Setting 40. Walkway Fitting Technology Walkway Fitting 41. Tower Erection Technology 42. Cable Pulling : A critical Milestone Technology 43. Cable Hoisting Technology 44. Suspender fitting Technology 45. Wind guy System Technology 46. Tools for Construction and Bridge Erection Technology 47. 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 Sus