Major causes of bridge failure

Reasons for Failure during construction or soon after

1. Deficiency in design / shift from actual design
2. Poor detailing (for rcc bridge), Poor connection between the structural elements (fitting of bolts or welding) in steel bridge.
3. Poor quality construction.
4. Poor material quantity.
5. Natural disasters like severe earthquake, fire, increase in the wind velocity, Tsunami, Floods.
6. Man made disasters like bomb blast.

Reasons for Failure a long time after construction

1. Failure of primary load carrying members by accidents
2. Changes in use (for eg:- Driving on foot-over bridges or driving of heavy vehicles on a bridge which is designed for small vehicles )
3. Due to overloading
4. Natural disasters like severe earthquake, fire, increase in the wind velocity, Tsunami, Floods.
5. Man made disasters like bomb blast.
6. Deterioration arising out of poor quality of materials, construction and lack of maintenance.
7. Exposure to adverse environment, not considered in original design.