There could be several reasons that led to the collapse of the Himalaya bridge outside the CSMT station that killed six and injured more than 30 pedestrians. However, structural engineers, and architects claim that primafacie corrosion could be a reason why the floor of the bridge gave away. The main reason being attributed to the collapse is lack of maintenance.
Satish C Dhupelia, a renowned structural architect says that the floor of the bridge gave away. "In my opinion the joists of the bridge on which the floor rests is what must have corroded and it wouldn't have come to the notice. Corrosion of steel in a city like Mumbai because of the weather conditions does occur." Joist is on what the floor resides and even the girders, beams of the bridges takes support from it.
Most architects and engineers claims that maintenance is what the bridge needed, and proper maintenance could have avoided such a mishap. Dhupelia further points out that, we have this habit of constructing infrastructure, but focus on maintenance isn't there. "We should maintain things, the British era bridges have been there for a long time. They were meant to bear two tonne vehicular traffic. But now, they face over 20 tonnes of vehicular traffic."
Architect Manoj Daisaria, who in his analysis said, "Main N-girders look intact, secondary beams appear to have failed along with the slab. Authorities need to have periodical supervision and checking for corrosion if any in the steel, and take remedial measures from time to time in order to avoid such calamity in the future."
There is another fear that many keep talking about and it is vibrations in the bridge. However, Dhupelia claims that vibration is a part and parcel of the bridge. It is meant to vibrate based on the composition of the bridge, and all bridges immaterial whether vehicular or pedestrian does vibrate. Shirish Sukhadame, former president of Practising Engineers Architects and Town Planners Association (PEATA) said, "Because a bridge cannot have rigidity it needs elasticity and hence there's vibration. When there weight it goes down a bit and then later takes shape."
According to Sukhadame, who also use to take the bridge on regular basis to reach Sir JJ School of Arts says that if a bridge moves in vertical direction then it isn't much of a concern.
