Grameen Sampark (December 2015) English Version
2015 Edition

Overview & Historical Evolution: Highlights from MORD 28

• Development of Trail Bridges:

  • Community construction of trail bridges began in 1989.
  • Annually 200+ bridges built during 2000-2008.
  • Over 300 bridges completed in 2012/13.
  • Longest bridge example: Dodhara Chandani spanning 1.4 km.

• Societal Benefits:

  • Enhanced access to education, healthcare, and markets.
  • Improved safety, mobility, and social connectivity.
  • Trail bridges serve as vital lifelines for rural populations.

• Bridge Classifications:

  • Suspension Bridge: Equipped with towers anchoring main cables; walkway with upward curvature; more complex and costly.
  • Suspended Bridge: Lacks towers; simpler, cost-effective; foundations positioned high on banks; maximum span approximately 350 m.

• Standardization & Manuals:

  • SBD Standards (1984) covering survey, design, construction, drawings, and costing.
  • BBLL Standard emphasizing designs feasible for community construction and cost efficiency.
  • SSTB (Short-Span Trail Bridge): Up to 120 m span using simpler techniques.
  • LSTB (Long-Span Trail Bridge): Designed for wider rivers with robust specifications.

• Community Bridge Construction Workflow:

  1. Community initiates bridge request.
  2. District Development Committee (DDC) prioritizes and prepares investment packages.
  3. User Committee formed with minimum 30% female members.
  4. Surveys, designs, and cost estimations prepared jointly by DDC and NGOs.
  5. Formal agreements signed; construction commences.
  6. Maintenance committee established post-construction.

Comparative Table: Bridge Types & Span

Funding and Development Partner Involvement: Core Aspects from MORD 28

1. Community-Driven Financing & Execution:

   • Bridge proposals initiated by communities through Village Development Committee (VDC) to District Development Committee (DDC).
   • Investment packages formulated based on detailed community surveys.
   • User Committees (UC) formed with at least 30% women representation.
   • Agreements established involving Community Development Committees (CDC), VDC, UC, and partner agencies.
   • Utilization of local resources and labor to minimize costs and promote ownership.

2. Role of Development Collaborators:

   • Provision of technical guidance, financial aid, and capacity development.
   • Support in standardization of bridge types (SSTB, LSTB, BBLL).
   • Facilitation of training programs and quality assurance through district laboratories.
   • Assistance in monitoring, evaluation, and maintenance frameworks.

3. Standardized Technical Documentation:

   • Manuals for Short-Span Trail Bridges (SSTB) and Long-Span Trail Bridges (LSTB).
   • Adaptation of suspension and suspended bridge designs for local topography.
   • Focus on cost-efficient, locally sourced materials and skills.

4. Quality Control & Laboratory Infrastructure:

   • Establishment of district labs equipped for comprehensive material testing.
   • Revenue models implemented to sustain laboratory operations.
   • Ongoing training and calibration activities ensure reliable testing.

Summary Table: Funding Activities & Stakeholder Roles

Simplified Workflow (Mermaid.js)

flowchart TD
    A[Community Initiative] --> B[Submit Application to VDC]
    B --> C[Survey & Package Preparation by DDC]
    C --> D[User Committee Formation]
    D --> E[Agreement Finalization]
    E --> F[Construction & Oversight]
    F --> G[District Lab Quality Testing]
    G --> H[Bridge Handover & Maintenance Setup]

Note: Financing primarily stems from community contributions supported extensively by development partners providing technical, financial, and capacity-building assistance.

Execution Framework & Community Engagement in Trail Bridge Projects (MORD 28)

Key Insights:

• Community-Led Initiatives: Bridge projects are initiated by communities submitting applications via local governance bodies (VDC to DDC).
• User Committee Formation: A User Committee (UC) with at least 30% female membership is established to ensure inclusive representation.
• Surveying & Prioritization: Community-based surveys guide bridge site prioritization; technical designs and cost estimates are prepared by DDC.
• Roles & Responsibilities:
  • Community Development Committee (CDC) and NGOs support project monitoring.
  • UC manages local materials and labor utilization.
  • DDC supervises technical and financial aspects.
• Standardized Bridge Designs: Simplified, community-friendly designs (BBLL and SSTB) ensure durability and affordability.
• Capacity Development: Training local artisans and fabricators enhances sustainability.
• Maintenance: Post-construction, maintenance committees are formed to oversee bridge upkeep.

Stepwise Implementation Summary:

Advantages of Community Engagement:

• Empowers stakeholders locally.
• Cost reduction through local resource utilization.
• Bridges tailored to community-specific needs and conditions.
• Strengthens social cohesion and improves access to essential services.

Process Flow Diagram (Mermaid.js)

flowchart TD
    A[Community Initiative] --> B[Application via VDC to DDC]
    B --> C[DDC Prepares Investment Packages]
    C --> D[CDC Prioritizes Bridges]
    D --> E[User Committee Established]
    E --> F[Agreement Signing]
    F --> G[Construction & Supervision]
    G --> H[Bridge Handover]
    H --> I[Maintenance Committee Formation]

For detailed design norms, refer to:

• Long-Span Trail Bridge Manual (LSTB)
• Short-Span Trail Bridge Handbook (SSTB)
• BBLL Standard

Milestones and Benefits of Trail Bridges in Nepal (MORD 28)

Key Achievements:

• More than 5,000 pedestrian trail bridges constructed nationwide, spanning from the high Himalayas to the Terai plains.
• Longest pedestrian bridge: Dodhara Chandani, with a span of 1.5 km.
• Highest altitude bridge: Kangla Bridge at 4700 m elevation.
• Fiscal year 2012/13 saw the construction of over 300 bridges; 325 bridges were completed within a year.
• Average daily footfalls approximate 1 million crossings, saving nearly 2 million hours of detour time.
• Economic benefits correspond to approximately NRs. 50 million in daily productivity, based on government labor rates.

Positive Outcomes for Communities

• Improved accessibility to education, healthcare, and marketplaces.
• Reduction in physical hardships and poverty levels.
• Enhanced safety and year-round mobility.
• Trail bridges recognized as essential lifelines for rural inhabitants.

Bridge Types & Technical Specifications

• Standardized designs facilitate mass production and cost efficiency.
• Relevant manuals include:
  • Long-Span Trail Bridge Standard Technical Manual (LSTB)
  • Short-Span Trail Bridge Standard Technical Handbook (SSTB) (for spans up to 120 m)

Community-Based Implementation Process

flowchart TD
    A[Community Initiates Application] --> B[DDC Collects Requests, Prepares Packages]
    B --> C[Community Development Committee Prioritizes]
    C --> D[User Committee Formed]
    D --> E[Design & Survey by DDC & NGO]
    E --> F[Agreement Signed by CDC, VDC, UC]
    F --> G[Construction by Licensed Inspecting Consultant & Local Labor]
    G --> H[Bridge Handover & Maintenance Committee Formation]

Bridge Types & Technical Criteria (MORD 28 Overview)

Principal Bridge Categories:

• Suspension Bridges:

  • Walkway is suspended from vertical cables attached to main cables, which are stretched between towers.
  • Towers are anchored on rocky cliffs or masonry foundations.
  • Walkways are cambered with an upward curve.
  • Require advanced expertise and higher construction costs.

• Suspended Bridges:

  • No towers present; walkway hangs from suspenders attached to main cables.
  • Foundations are placed high on banks to maintain adequate freeboard.
  • Simpler and more economical than suspension bridges.
  • Example: The longest suspended bridge span is 350 m in Khotang.

Technical Documentation:

• LSTB Manual (Long-Span Trail Bridge): For spans exceeding 120 m, addressing complex terrains.
• SSTB Manual (Short-Span Trail Bridge): For spans up to 120 m, focusing on simpler designs suited for local trails.
• BBLL Standard: Community-friendly designs leveraging local materials and skills.

Design and Construction Principles:

• Standardization supports mass production of wire ropes, prefabricated steel components, and standardized tools.
• Emphasis on durability, functionality, and cost efficiency.
• Active involvement of communities is crucial for maintenance and long-term sustainability.

Typical Span Ranges & Application

Simplified Community Construction Workflow

flowchart TD
    A[Community Initiative] --> B[Application via VDC to DDC]
    B --> C[Preparation of Investment Packages by DDC]
    C --> D[Prioritization by Community Development Committee]
    D --> E[User Committee Formation]
    E --> F[Survey & Design by DDC and NGO]
    F --> G[Agreement Signing]
    G --> H[Foundation Work & Construction]
    H --> I[Bridge Handover and Maintenance Committee Setup]

Summary: Nepal primarily utilizes suspension and suspended pedestrian trail bridges designed to address varied terrain and community needs.

Technical Distinction Between Short-Span and Long-Span Bridges (MORD 28)

According to Nepal’s trail bridge specifications:

Key Features:

• Short-span bridges emphasize affordability, use of indigenous materials, and community-led construction.
• Long-span bridges require sophisticated design, advanced fabrication, and higher technical expertise (e.g., suspension bridges with towers).
• Suspension bridges feature cambered walkways with cables anchored on rocky banks or masonry blocks.
• Suspended bridges lack towers; foundations must be elevated sufficiently for flood clearance.

Technical Standards:

• Employ standardized designs to enable bulk production and cost savings.
• Mass procurement of wire ropes and prefabricated steel parts reduces expenses.
• Community participation is vital in SSTB projects; LSTB demands expert supervision.

Overview Diagram:

graph LR
A[Trail Bridges] --> B[Short-Span (≤120 m)]
A --> C[Long-Span (>120 m)]
B --> D[Community-led Construction]
C --> E[Expert-designed Suspension Bridges]
D --> F[Suitable for Seasonal Streams]
E --> G[Designed for Wide Rivers and Challenging Terrain]

This classification aids in optimizing design decisions, budgets, and construction methodologies based on span and site conditions.

Essential Specifications & Design Protocols (In the Context of MORD 28)

1. Bridge Categories:

• Suspension Bridges: Walkway suspended from vertical cables attached to main cables stretched between towers; requires higher expertise and costs.
• Suspended Bridges: Walkway supported by suspenders attached to main cables without towers; more cost-effective; foundations must be elevated to provide freeboard.

2. Standardized Manuals:

• Long-Span Trail Bridge (LSTB) Manual, Volume A: Design-focused documentation.
• Short-Span Trail Bridge (SSTB) Handbook:
  • Volume I: Guidelines for survey, design, and construction.
  • Volume II: Construction templates and forms.
• BBLL Standard: Community-friendly design inspired by traditional Baglung bridges, optimized for local skills and materials, suited for spans up to 120 m.

3. Technical Norms:

• Standardization enables mass production and economies of scale.
• Suspension bridges utilize cambered walkways.
• Cable anchorage must be on solid rock or masonry blocks.
• Suspended bridges require elevated foundations for flood clearance.

4. Community Bridge Construction Workflow:

• Initiation by community → Application to DDC → Survey & design → User Committee formation → Construction → Maintenance committee setup.

Indicative Design Parameters

Diagram: Suspension vs Suspended Bridge

graph LR
A[Main Cable] -->|Suspension| B[Towers on Riverbanks]
B --> C[Anchorage on rock or masonry]
A --> D[Vertical Suspenders]
D --> E[Upward Cambered Walkway]

subgraph Suspended Bridge
F[Main Cable] --> G[Suspenders]
G --> H[Walkway]
I[Elevated Foundations] -->|Support| F
end

Additional Information:

• Manuals provide comprehensive guidance on design, fabrication, and construction techniques.

Sequential Steps for Community-Based Bridge Construction (Aligned with MORD 28)

1. Community Identification of Need:

   • Community recognizes the requirement and submits an application to the District Development Committee (DDC) through the Village Development Committee (VDC).

2. Surveying and Prioritization:

   • DDC collects requests, conducts site surveys, and prioritizes bridge locations according to community needs and technical feasibility.

3. User Committee Formation:

   • A User Committee (UC) is established, ensuring at least 30% women representation to ensure inclusivity.

4. Design and Cost Estimation:

   • DDC along with supporting NGOs prepares detailed design drawings and cost estimates following established manuals (SSTB for spans ≤120 m, LSTB for longer spans).

5. Approval and Agreement:

   • Formal agreements are signed among CDC, VDC, UC, and supporting organizations outlining responsibilities and funding.

6. Construction Phase:

   • UC manages local labor and materials; construction is supervised by technical agencies; includes foundation laying, cable anchoring, and deck installation.

7. Handover and Maintenance:

   • Upon completion, the bridge is handed over to the community; maintenance committee is formed to oversee upkeep.

Reference Table: Bridge Types and Manuals

Important Considerations

• Standardization minimizes costs and expedites design.
• Community engagement is critical for sustainability.
• Adherence to SBD standards ensures safety and durability.
• Preference for local materials; wire ropes and steel parts are mass-produced for cost efficiency.

flowchart TD
    A[Community identifies need]
    B[Application submitted to DDC via VDC]
    C[Surveys and prioritization by DDC]
    D[Formation of User Committee]
    E[Design and cost estimation by DDC/NGO]
    F[Agreement signing]
    G[Construction supervised by UC]
    H[Handover and maintenance committee formation]

    A --> B --> C --> D --> E --> F --> G --> H

Quality Control and Laboratory Testing Procedures (MORD 28 Highlights)

1. Quality Assurance Framework:

• Monitoring occurs at three levels: National, State, and Field.
• From Phase-II (2002-03), field laboratories with minimum required equipment are mandatory for every construction package.
• District laboratories are equipped for comprehensive testing of material physical properties, such as plasticity index, impact and crushing strength, California Bearing Ratio (CBR), and concrete cube strength.
• Testing distribution: 20% of materials tested in authorized district labs, 80% in field labs.

2. Laboratory Staffing and Management:

• Junior Engineer acts as lab in-charge.
• Two Civil Engineer Assistants conduct sample testing and result documentation.
• Contract labor assists with material handling and testing support.

3. Testing Workflow:

• Samples received with proper tagging and expected result timelines.
• Samples sorted chronologically and scheduled for testing.
• Results prepared, issued, and samples preserved for verification if needed.

4. Calibration and Training:

• Calibration carried out by trained Junior Engineers and accredited laboratories.
• Continuous training programs conducted for departmental and contractor personnel.

5. Financial Sustainability:

Common Tests and Equipment in Field and District Labs:

flowchart TD
    A[Sample Collection] --> B[Sample Receipt & Tagging]
    B --> C[Scheduling & Sorting]
    C --> D[Testing by Lab Staff]
    D --> E[Result Preparation & Delivery]
    E --> F[Sample Storage for Verification]

Training and Capacity Development: Core Elements (as per MORD 28)

Context Overview:

• Since 1989, community-led trail bridge construction has been practiced.
• Standardized manuals for suspension and suspended bridges have been developed.
• Simplified bridge designs (BBLL & SSTB) enable execution by local communities.
• Training focuses on local craftsmanship, material usage, and maintenance protocols.
• Quality assurance is supported by district and field laboratories under PMGSY.

Training Details and Components

Typical Training and Project Flow

flowchart TD
    A[Community Initiation] --> B[Application to DDC via VDC]
    B --> C[Survey & Prioritization by CDC]
    C --> D[User Committee Formation]
    D --> E[Training on Design & Construction]
    E --> F[Quality Testing & Oversight]
    F --> G[Bridge Construction]
    G --> H[Formation of Maintenance Committee]

Training Advantages

• Empowers local communities with technical knowledge.
• Promotes economical and durable bridge construction.
• Enhances safety, mobility, and social-economic conditions.
• Fosters sustainable maintenance and quality assurance.

For comprehensive design details, consult the Long-Span Trail Bridge Manual and Short-Span Trail Bridge Handbook associated with MORD 28.

Maintenance and Longevity: Essential Points from MORD 28

1. Community Engagement and Institutional Mechanisms:

• Formation of User Committees (UC) after bridge completion to take responsibility for maintenance.
• Maintenance committees conduct routine inspections and oversee repairs.
• Utilization of local materials and expertise ensures cost-effective maintenance.

2. Adherence to Technical Standards and Manuals:

• Use of SBD Standards and BBLL technology fosters durable, community-executable bridge designs.
• Manuals such as Long-Span Trail Bridge Manual (Vol A) and Short-Span Trail Bridge Handbook provide guidance on maintenance procedures.

3. Quality Control and Testing:

• District laboratories equipped with calibrated instruments provide ongoing material testing.
• Regular testing of soil, aggregates, and concrete maintains structural integrity.

4. Maintenance Workflow:

flowchart LR
    A[Bridge Completion] --> B[Establish Maintenance Committee]
    B --> C[Regular Inspections and Minor Repairs]
    C --> D[Major Repairs and Material Procurement]
    D --> E[Community Feedback and Training]
    E --> B

5. Procedures and Best Practices:

• Maintenance contracts typically span 5 years, incorporated into construction agreements.
• Local workshops contribute to fabrication and repair activities, ensuring sustainability.
• Ongoing training for community members and staff supports quality upkeep.

Maintenance Responsibilities Overview

In summary, bridge sustainability is achieved through community ownership, adherence to technical standards, continuous quality assurance, and structured maintenance systems.

Technical Specifications & Formulas from MORD 28 on Pedestrian Trail Bridges

Bridge Types and Design Protocols

• Suspension Bridge: Walkway suspended from vertical suspenders on main cables stretched between towers anchored on rocky or masonry foundations.
• Suspended Bridge: No towers; walkway suspended from suspenders attached to main cables anchored on elevated riverbanks.
• Span Classification:
  • Short-Span Trail Bridges (SSTB): Spans up to 120 m.
  • Long-Span Trail Bridges (LSTB): Spans exceeding 120 m; e.g., Dodhara Chandani Bridge at 1.4 km.

Design Manuals and Standards

• SBD Standards (1984): Five volumes covering survey, design, construction, drawings, and costing.
• BBLL Standard: Community-executable, cost-efficient design inspired by traditional Baglung bridges.
• LSTB Manual (Volume A): For long-span bridge design.
• SSTB Manuals (Volumes I & II): Focused on short-span bridges using local materials and skills.

Simplified Community Bridge Construction Sequence:

1. Community submits application through VDC to DDC.
2. DDC prepares investment packages informed by community surveys.
3. User Committee (UC) formed with 30% female representation.
4. Design, drawings, and costing done by DDC engineers.
5. Agreement signed among CDC, VDC, and UC.
6. Construction overseen by Licensed Inspecting Consultant (LIC); materials managed by UC.
7. Maintenance committee established after completion.

Technical Notes

• Cable anchorage must be on solid rock or masonry blocks.
• Suspension bridges have upward cambered walkways.
• Bulk procurement of wire ropes and prefabricated steel reduces costs.
• Community involvement is essential for sustainability and cost control.

Typical Cable Load Calculation for Suspension Bridges:

[ T = \frac{w \times L^2}{8 \times d} ] Where:

• (T) represents the tension in the cable,
• (w) is the uniform load per unit length,
• (L) denotes the span length,
• (d) is the sag (vertical displacement from cable lowest point to supports).

flowchart TD
  A[Community Initiative] --> B[Application via VDC to DDC]
  B --> C[...]