Dec 30: A severely weakened column on the fifth floor of the Poonam Chambers, has been determined to be the immediate cause of the September 16 collapse of the seven-storeyed Poonam Chambers office complex which killed 19 persons.This has been established in the report of an expert committee consisting of structural engineers Satish Dhupelia and Sailesh Mahimtura, submitted to the BMC Commissioner Girish Gokhale on December 15.
The exhaustive report which comprises around 250 pages of text and graphics and includes several recommendations, is yet to be made public by the corporation.
This is what happened to column no 14 on the fifth floor, which has been held directly responsible for the crash.
The column first lost its confined concrete cover and a portion of its core concrete was also dislodged due to disturbances at its base section. Unconscious of the damaging effects, deep cuts or `chases' had been made in the main load bearing structural RCC columns and slabs during interior decoration on the
fifth floor.
This had triggered distress development in this column which was accelerated beyond the point of control resulting in the crash. The column, which is still left standing amidst the building debris, was the focal point of four panels in the first collapse.
The report states that equipment had been mounted directly on flat slab panels without sub-frames to transfer loads directly to columns and without any devices for vibration isolation and absorption like anti-vibration pads and spring mounted floating base.
The report mentions that there were scattered locations of deficient workmanship of original construction in the building. These had been tacitly tolerated by the owners and occupants without timely correction. Moreover, a casual approach had been adopted to retrieve the situation without technical guidance from experts. However, the expert committee had not held any one particular person responsible for the building's partial collapse.
In its recommendations, the expert committee
has emphasised the need for ensuring durability in new structures and accountability in construction by establishing a direct dialogue with all agencies of the building industry like builders, developers and contractors. Committee stressed on the licensing and registration of interior designers, decorators and related trades to ensure accountability and controlling unconscious damage to a building structure while carrying out repairs. It has also recommended the incorporation of a `condition survey report' of buildings from accredited structural engineering experts for continuation of occupancy certificates at intervals.The committee noted with regret that neither members of the public nor persons who claimed to have personal knowledge to the building's potentially hazardous condition had deposed before the committee.
Copyright © 1997 Indian Express Newspapers (Bombay) Ltd.
