Joaquim D’Souza
After the miscarriage of the investigation on the collapse of the Mandovi Bridge, which was more a searchlight on scapegoats rather than a study on what caused the failure and what would have avoided it, we now have the report on the Ruby building in Canacona tabled.
From what has appeared in the press, the study appears very painstaking going by the enumerations of various tests, design parameters et al which go into the structural design, and construction of a building. It is stated that the building has been designed as a single frame, which is a good thing since that is the way the structure will behave at failure state. But a googly is thrown that wind and seismic loads are not considered. These loads are taken in a good analysis, but none of these came into play at the time of the collapse. It is a dichotomy that continuity and stiffness would not be taken in consideration in a space frame analysis. Further complex dynamic loads such as seismic are possible to be ascertained with accuracy only by Computer Aided Design. The compressive strengths of concrete are relevant and important, but unlikely to cause the collapse at this early stage.
This building suffered due to avarice to obtain an additional floor by ill-advised adjustments where the column footings were rested on unconsolidated fill. To make matters worse this fill was held by a RCC retaining wall, apparently strong but without stiffness to resist lateral deflection. As a result, under the self- load itself, there would be displacements and resulting stresses beyond the capacity of this poorly constructed and conceptualized design. The building could have been constructed by having the footings resting on the original ground, and the long columns having adequate stiffness and restraints by tie beams and all would be fine. The idiot, who improvised on the design, must also conceptualize the connecting bridges. The Report however is bang –on the grossly inadequate steel in the columns, which is apparent from the type of instantaneous collapse like a pack of cards.
The learning herein will be proper classification of the Registered RCC Consultants. If doctors don’t thread where they are not qualified, why Diploma or even Degree engineers should be empanelled with a carte blanche to design any type and size of structures. The understanding of behavior comes from learning only. Currently the qualification to design depends only on the networking of these engineers and not on their capabilities. So we can expect more Rubies and Pearls, but no wisdom.
