Different modes of failures of bridge structures under different stages of load either man-made or natural cause, is necessary to develop strong and highly sustainable structures.
Cause of Failure of Bridge Structures
Bridges are vast and heavy structures whose design is complicated and sophisticated similar to the way it is constructed. It can consume large time period and a huge investment. Any failure to this will affect the economy in terms of life safety and wealth.
The main factors that will affect the bridge failure are:
- The span length of the bridge
- The heavy load pattern acting on the structure with both the impact and the cyclic loads.
- Chances of load increasing for lifetime.
- The structure is subjected to extreme weather conditions without any form of cladding. They are subjected to aggressive climate changes, wind and moisture conditions.
- Foundations subjected to different changes based on different soil conditions. This is also subjected to various hydraulic effects.
- Heavy vehicle movements create damage to different structural elements of the bridge.
Fig: Failure of Bridge due to the scouring
The bridge use and function are mainly dependent on the loading of the bridge and the object over which the bridge must span.
From past histories and studies, major failures in the bridge is recorded due to the following issues:
- Foundation scouring causing overall collapse of the structure
- Steel members of the structure subjected to brittle, stress and fatigue corrosion cracking.
- Collision of vehicles with the girders and the piers, collision of the vehicles with the truss members or guides, shifting of the train loads, derailment of the train.
- Salting of the surface of the deck, resulting in the corrosion of the structure reinforcement. This results in the distress of the deck surface.
- Floor system subjected to corrosion damaging the roadway or the deck.
- Flood at the bottom of the bridge will result in horizontal loads on the bottom.