Forces and stresses to be considered in designing Road Bridges?
IRC:6 gives procedure for design and construction of road bridges in India. It gives information about load, forces and stresses to be considered in designing Road Bridges:
- Dead load due to
- Footway and kerb
- Self weight of parapet
- Deck Slab
- Live Load
- Snow Load
- Impact caused due to:
- Floating bodies or vesssels as the case may be
- Vehicles
- Wind load
- Water current
- Longitudinal forces caused by:
- Tractive effort caused through acceleration of the driving wheels.
- Bracking effort resulting from the application of brakes to braked wheels.
- Frictional resistance offered to the movement or free bearings due to change of temperature or any other cause.
- Centrifugal forces (in case a road bridge situated on a curve).
- Secondary stresses due to:
- Movement of supports.
- To the deformations in geometrical shape of structure.
- Members resulting from causes such as rigidity of end connection.
- Loads applied at intermediate points of trusses.
- Restrictive shrinkage of concrete floor beams.
- Buoyancy
- Earth pressure including live load surcharge if any
- Seismic forces.
- Temperature effects
- Deformation stresses
- Secondary stresses
- Erection stresses
- Permissible increase in stresses in various members due to combination of load.
