Solution considerations

Solution considerations

1. Truss Type

   • Must distribute vertical and horizontal loads across tensile and compressive members efficiently/evenly throughout the entire structure
     • preestablished efficient truss types
       • E.g. Pratt truss
       • Warren truss
       • K truss
   • Must efficiently utilise members by avoiding unnecessary zero-force members and excessive compressive members to maximise bridge performance
   • Must not over/under-engineer the bridge design to reduce complexity, material usage and environmental impact

2. Dimension requirements

   • Real world
     • Width has to be 6m
     • Any truss structure above the walkway deck should meet clearance requirement of at least 2.7m
     • Sufficient deck width for bidirectional travel of at least 3.5m
     • Structure cannot extend below a projected horizontal line across the abutment upper surfaces
   • Prototype
     • Truss members are 3mm thick
     • Truss members are 3mm wide
     • Real world dimensions but scaled by 1:20 (e.g. 6m to 300mm)

3. Environmental loading

   • Real world
     • Must withstand live loads of pedestrian traffic to increase service life
       • Pedestrians
       • Bicycles
       • Strollers
       • E.g. PMV (personal mobility vehicle)
     • Must withstand environmental loads to increase service life
       • Wind forces
       • E.g. Seismic forces
     • Must withstand thermal loads to increase service life
       • E.g. Hot/Cold climates
     • Must withstand hydraulic loads
       • E.g. Water current forces
   • Prototype
     • The design must withstand a 50N point-force test load at the midspan
     • The design must have a safety factor above 2 (withstand at least 100N)

4. Materials

   • Real world
     • Timber or a material with a similar appearance to blend in with the natural surroundings
     • Treated timber
       • E.g. Glulam (Glued Laminated Timber)
       • LVL (Laminated Veneer Lumber)
       • Treated Pine (H3-H6)
     • Hidden or masked steel joints/reinforcements for strength
   • Prototype
     • Scaled down truss face will be laser cut from 3mm plywood sheet