PANAJI
The Chief Minister Pramod Sawant on Thursday informed the House that the slab of Kala Academy's iconic open-air auditorium was under “corrosion attack for over 43 years” resulting in “sudden collapse of structural steel members or RCC slab”.
In a significant embarrassment to the State government, a large portion of the slab collapsed on July 17.
The reports submitted by Goa Public Works Department, Rail India Technical and Economic Service (RITES), IIT Mumbai and an interim report from IIT Delhi identifying the causes for the collapse of the structure, were tabled before the State Legislative Assembly.
“The reports indicated that failure of structure is basically due to corrosion of structural steel ISMB and N-Girders near support and also not being anchored or embedded in RCC slab causing reduction of load and moment resisting capacity of structural members,” Sawant said quoting the findings of the reports.
“Hence, composite structures were under corrosion attack over 43 years resulting in sudden collapse of structural steel members/RCC slab,” he added.
The Chief Minister further said that the structural repairs or strengthening of the open auditorium was not carried out and 40 cm average thickness old water proofing was removed and a new layer was laid with thickness of 20-30 cm including chemical waterproofing which was completed before the last monsoon.
The House was informed that the structure, though an integral part of the Kala Academy complex, is a standalone structure, which consists of a seating area and covered stage of composite structure consisting of RCC slab of 5.6-10 cm thickness resting on the I-beam of depth 40cm, columns and masonary walls. The terrace of the stage is covered with brickbat coba waterproofing with china mosaic flooring having average thickness of 40 cm.
Sawant said that three independent reports conducted prior to commencement of the work of KA -- the Goa College of Engineering, Gem ENGSERV Ltd and IIT Madras mentioned that “there is no need of demolition of the complex”.
The PWD in its finding has ruled out that the collapse was due to the ongoing renovation work of the Kala Academy or due to negligence as it was a standalone structure.
“In case if we had to take up the renovation or refurbishment and rehabilitation of the open auditorium, the only possible way was for the demolition of the entire structure as the slab was placed on structural steel and embedded in beam, column and masonary wall,” the report stated.
“As the structural repair work is not carried out to the collapse structure and no major renovation or repair works are also carried out and also due to the fact that the structure being nearly 43 year old, the entire incident occurred due to the ongoing renovation work or due to negligence is ruled out at this juncture,” PWD said further.
As per RITES findings, it is said “prima facie it seems the collapse of the slab may have occurred due to rusting of the steel support of the slab”.
IIT Mumbai in its report concluded that the “percentage of corrosion is around 19-30 per cent, since the said structure was exposed to adverse weathering effects and located adjacent to the sea belt implies that failure is due to corrosion of the structure steel ISMB and N-girder near supports. Along with this the structural steel ISMB was not anchored or embedded in RCC slab causing reduced load and moment resisting capacity of the structure members and hence the structure was under corrosion attack resulting into sudden collapse”.
The final report of IIT Delhi will be submitted to the government only after detailed investigation is completed.
