Considered safe from seismic activities with zone-2 (least active) categorisation, Bengaluru has caught the country’s attention with a series of building collapses in recent weeks.
The trend caused concerns about existing structures and raised questions over the quality of construction at a time when Bengaluru is growing vertically to accommodate the swelling population.
While the BBMP is identifying such weak buildings across the city, a bunch of trade and expert bodies like the Association of Consulting Civil Engineers (India), the Indian Concrete Institute and the Institute for Research Development and Training of Construction Trades and Management (INSTRUCT) have asked the state to implement the National Building Code 2016.
Engineers from these organisations visited the building collapse sites as part of the forensic civil engineering analysis and detailed documentation. “Civil engineers weren’t involved at any stage of the buildings’ construction,” said Shrikant S Channal, Chairperson, Association of Consulting Civil Engineers (India). “The buildings breached plans, added floors or did renovations that triggered the collapse.”
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H R Girish from the Indian Concrete Institute said many concrete buildings in the city could be found with similar breaches. “People rely on illiterate or experienced masons to build many tall structures in Bengaluru and end up with problems a few years later,” he said, blaming unqualified technicians and inexperienced contractors for the tilting and collapsing structures.
The fact that low-rise buildings have collapsed highlights the role of unprofessional and unskilled contractors. “Government agencies mandate civil engineers’ involvement in constructing high-rise buildings, but are silent while approving plans for low-rise structures,” Channal said.
While high-rises are just 1.6% of the buildings in Bengaluru, the remaining are low-rises 98.4% are low-rise buildings with G+4 floors. All the violations of building by-law and deviation from the approved plan are largely reported from these buildings due to the involvement of unprofessional contractors.
“Construction industry is unorganised, and labourers often don’t have required skills,” Channal explained. “Our associations periodically hold programmes to train them in the latest techniques and methods.”
The National Building Code of India was introduced in 2016 to end unprofessional practices. But the state and civic agencies are yet to include it in their provisions.
“We have been writing to the chief secretary, the BBMP chief commissioner and the Town Planning Department to include the NBC but none of them responded,” Girish said. The NBC can help avoid structural damages, he added.
The engineering body also believes that high-rises are not the solution within the city, given the topography and soil conditions. “Horizontal growth would spur development in adjoining districts and boost economic prosperity,” Channal said, adding that deep excavations in densely populated inner-city areas will cause damage to the structures.
The associations also pointed to the lakes occupying the city landscape. “Lakes have been filled up in many areas to construct buildings. If they’re filled unscientifically and built upon, the base will cave in a few days and trigger the building collapse,”
Girish said.
Chairman of Indian Concrete Institute, Dr L R Manjunath, said not many contractors are aware of the types of cements and the right mixture of sand, jelly and cement.
“India is the second-largest producer of quality cement in the world. But untrained professionals don’t use the right quality cement,” he said.
INSTRUCT Chairman K L Mohan Rao said buildings must be examined for structural defect once in three to four years. “They must undergo tests and inspections. But no one bothers until the building turns 35 or 40,” he said.
The associations said people bypass civil engineers fearing mounting expenses. “The cost of hiring a civil engineer is just a fraction of what it takes to build the structure,” Channal said.
“Hiring an experienced engineer solves many problems. An engineer will test the soil strength, design pillars and structure as per the load, and supervise the execution,” Channal added.
Government must also set up an engineering regulatory body on the lines of the medical council. If structures collapse, engineers responsible for construction must be punished and disqualified from work.