The Gujarat government-appointed Special Investigation Team (SIT) has released a probe report on the Morbi suspension bridge collapse incident, which reveals that nearly half of the wires on a cable were corroded. The report added that the welding of old suspenders with new ones also resulted in the collapse of the bridge which killed 135 people.
The 'Preliminary Report on Morbi Bridge Incident' submitted by the five-member SIT in December 2022 also found several lapses in repairs, maintenance and operation of the bridge, reported PTI.
The SIT included IAS officer Rajkumar Beniwal, IPS officer Subhash Trivedi, a secretary and a chief engineer from the state Roads and Building Department, and a professor of structural engineering.
According to the report, of the two main cables, one was corroded, and nearly half of its wires "may be already broken" even before it snapped on the fateful October 30 evening. The bridge was built by the erstwhile rulers in 1887 over river Machchhu and the operation and maintenance of the British-era suspension bridge were entrusted to Ajanta Manufacturing Limited (Oreva Group).
According to the SIT, the main cable on the upstream side of the river snapped, leading to the tragedy. Each cable was formed by seven strands, each comprising seven steel wires. A total of 49 wires were clubbed together in seven strands to form this cable, the SIT report said.
"It was observed that out of the 49 wires (of that cable), 22 were corroded, which indicates that those wires may have already broken before the incident. The remaining 27 wires recently broke," the SIT said in its report.
It added that during the renovation work, "old suspenders (steel rods which connect the cable with the platform deck) were welded with the new suspenders. Hence the behaviour of suspenders changed. In these types of bridges, single rod suspenders should be used to bear the load".
The report also said that the Morbi Municipality awarded the contract to maintain and operate the bridge to Oreva Group without the approval of the general board. The bridge was closed for renovation in March 2022 and opened on October 26 without any prior approval or inspection.
At the time of the accident, there were nearly 300 persons on the bridge, which was "far more" than the load-bearing capacity of the bridge.
Other factors which contributed to the collapse included replacing individual wooden planks with an aluminium deck. "Walking structure was made up of rigid aluminium panels instead of flexible wooden planks. If there were individual wooden planks (which were there before renovation), the number of casualties could have been lower. Moreover, no load test or structure test was conducted before opening the bridge," it added.
The aluminium honeycomb panels were fixed without any gap in between, which makes the deck less flexible to deform in its own plane, said the SIT, adding that the use of aluminium could have increased the overall weight of the bridge too.
(With inputs from PTI)
