Structural non-compliance increases quake risk

Non-compliance on structures and faulty construction ignoring risk factors have increased the damage of earthquake risk signficantly accross the counry, opined experts.
National Project Director of the Comprehensive Disaster Management Programmme (CDMP) Mohammad Abdul Qayyum said damage to be caused by a tremor depends on some factors like distance and intensity of earthquake, how much energy is released by the tremor and the level of structural compliances.
"Unfortunately, there is a lack of structural compliance because building codes are being flagrantly flouted," he said.
Citing the latest CDMP study on six districts  Rajshahi, Rangpur, Bogra, Dinajpur, Tangail and Mymensingh, he said there are more than 0.45 million concrete structures. Of the nearly 35,000 structures, around 13,000 would face complete destruction. Mymensingh will face the worst as 97 per cent buildings there will collapse.
The CDMP, which conducts risk assessment of natural disasters, found some 78,323 buildings vulnerable to complete collapse if a 6-magnitude earthquake originating from the Madhupur fault line shakes Dhaka. It will cause havoc on the densely-populated capital city.
In case of a 7.5-magnitude earthquake originating from Madhupur fault line  (near Dhaka city), about 72,316 buildings in the capital will be destroyed totally and 53,166 others partially.
Professor of BUET's Civil Engineering Department Dr Mehedi Ahmed Ansari said the likely financial damage due to earthquake was assessed after conducting preliminary and rigorous sampling on around five per cent buildings in the capital.
He said they collected satellite pictures of the buildings located in the worst-case areas of Dhaka.
He said the capital has now been expanding towards low-lying areas, filled up by soft land that has intensified the risks of disasters.
Citing another study, the BUET professor said 65 per cent land in the Rajuk area is soft and the remaining 35 per cent is original. "There is no alternative to strict enforcement of building codes," he said adding that most buildings in the capital lack enough compliance to face a tremor.
Seeking anonymity, a senior Rajuk official said the city development authority in most cases approved building designs without checking whether the structures are quake-resistant, although the building codes have made it mandatory that each structure must have compliance to withstand tremor of at least 7.5-magnitude.
"In fact, the Rajuk doesn't have enough capacity to enforce it properly," he said.
The Rajuk with the help of city corporations made a list of 321 risky residential buildings in the city in 2010 following tilting of a multi-storey building in the capital's Kathal Bagan area.
Since then, the authorities failed to make any visible progress over the issue even in three years in the city with 400 years' history.
Officials concerned said they held meetings on several occasions in the past but failed to reach a decision as to who would take the responsibility of making the capital free from risk of an earthquake.
Rajuk Chief Engineer Md Hafizur Rahman Munshi said the housing and public works minister at a recent meeting instructed them to identify the vulnerable structures with red colour.
"We're now preparing it as the latest earthquake in Nepal has alarmed us," he added.
Talking about the issue, urban planner Mubasshar Hussein said there are hundreds of Rana Plazas in the capital city, which were built without following building codes.
The government should not waste any more time in going for strict enforcement of the building codes, he said adding that the architects need at least two years to inspect 3,000 apparel factories after the Rana Plaza tragedy.  
"If the government starts the process to identify vulnerable buildings right now, it will take at least 10 years to finish the job," he said.
A strong earthquake of 8.6-magnitude occurred in Assam on August 15 in 1950, killing 1,526 people. Another 8.1-magnitude quake hit Assam on June 12 in 1897, killing 1,500.
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