www.sefindia.org

[amitjha]

Dear All
Though its hard to believe that wind currents could be so strong to cause bridge collapse but thats how it is being reported. Do share your thoughts on possible causes of collapse. This was under construction 8 years or so, missed deadline, change of contractors, funding issues and ultimately this collapse luckily there was no loss of life, it would have been catastrophe if this was comissioned in future.

References:


https://youtube.com/watch?v=MQXNFCm4zdk

[amitjha]

https://www.indiatoday.in/india/telangana/story/telangana-bridge-collapse-in-peddapalli-was-under-construction-for-8-years-2530756-2024-04-23

https://timesofindia.indiatimes.com/city/hyderabad/girders-of-under-construction-bridge-collapse-in-telanganas-peddapalli-due-to-gales-and-wind/articleshow/109530527.cms

https://www.deccanherald.com/india/telangana/watch-under-construction-bridge-collapses-in-telangana-2990746

[vikram.jeet]

Concrete Bridge collapse due to strong wind :-

Not digestible for  conc bridge,, had it been steel bridge,, it could happen , if not executed correctly.

Concrete bridges are more prone to earthquake,, than wind effects.

If any EQ event happened,, chances of failure exist for under construction bridge.

Assuming  for Wind action :
Girder span 50m
Girder depth = 1.5m
Girder av width = 0.35 m
Bottom /top bulb width = 0.45m
Wind pressure = 200 kg/m2
Lateral wind cofficient = 1.2
Uplift wind coeff = 1.5

Wind force = (200*1.2)* 1.5* 50 = 18000 kg = 18 tonne
Wind lateral force on each support = 9.0 tonne
Wind uplift = (200*1.5)0.45*50 = 6.75 tonne

Dead wt of girder = av 0.35*1.5 * 50*2.500 = 65.6 tonne
Dead wt on each support = 32.8 - 6.75/2 = 29.4 tonne

Even if girder is placed on pier cap during construction (bearings not installed)

The stabilizing lateral force
Taking  cieff = 0.6 (friction coeff conc to conc wet conditions)
Stabilizing F = 0.6* 29.4 = 17.6 tonne  cf 9.0 tonne

Hence ample FOS available ,, Girder can not slip down due to wind action

Other reasons :-
Lateral reinforcement deficient in girder
Foundation instability  along transverse direction

[vikram.jeet]

In case  longitudinal girders are tied through x girders ,, lateral strength goes up many times,, but during construction,, girders must be tied with temporary steel structure till time , the x girders are construction.