Chattogram City: Quake risk looms amid building code violations

While Chattogram city is already vulnerable to severe earthquakes due to its geographical location, experts warn that unplanned urbanisation, widespread building code violations, and poor monitoring have further heightened the risks.

At least 70 percent of the port city's multi-storey buildings are at risk of collapse in the event of a major earthquake of magnitude 7 or higher, they said.

According to the Chattogram Development Authority, the city has 4,11,721 buildings -- 3,87,757 are up to six storeys high, 13,480 are seven to ten storeys, 415 are 11–15 storeys, 50 are 16–20 storeys, and nine are above 20 storeys.

Experts say a significant portion of these high-rises is vulnerable because many were constructed in violation of building codes. In coastal areas like Chattogram, construction materials also deteriorate faster, while narrow roads can severely obstruct rescue operations after a major earthquake.

"The failure to properly follow the plans approved by the regulatory authority has increased the risk of collapse during an earthquake," said Dr Muhammad Rashidul Hasan, professor of Urban and Regional Planning at Cuet.

Experts also identify indiscriminate groundwater extraction as another factor weakening the city's geological foundation.

"This removal of supporting water pressure causes the surface layer to displace and settle, thereby increasing the vulnerability of high-rise buildings," Dr Rashidul explained.

Experts say the current situation is the result of years of regulatory negligence.

During the 5.7-magnitude quake on November 21, a six-storey building in Monsurabad tilted further towards an adjacent building. It had previously tilted during a 2016 quake, along with 11 other buildings in the city. A 6.1-magnitude earthquake in 1997 caused a five-storey building to collapse, killing over 20 people.

Small quakes, experts say, are often warnings of a major disaster.

"There is a risk of damage to 65–70 percent of multi-storey buildings in the port city in case of an earthquake of magnitude 7 to 8," said CDA chief engineer Kazi Hasan Bin Shams.

He said unlike Rajuk, CDA does not have a structural and design cell, and its manpower shortage makes regular inspections even more difficult.

Dr Rashidul said in Bangladesh, Chattogram and Sylhet fall in the highest-risk category. Yet many residents ignore building codes, and numerous buildings are constructed without proper expert supervision.

"CDA cannot avoid responsibility and must employ more manpower to monitor these irregularities," he added.

A six-storey building in Chattogram’s Mansurabad area tilted and leaned onto an adjacent structure following Friday’s earthquake. Photo: Collected

To minimise risks, Dr Rashidul emphasised identifying vulnerable buildings and retrofitting them with modern machinery and equipment.

Very old structures that cannot be repaired should be demolished, he said.

Residents, he stressed, must strictly follow building codes while constructing new buildings.

He also called for reducing groundwater extraction and prioritising the use of surface water.

Delwar Majumder, former president of the Institute of Engineers Bangladesh, Chattogram, said it is the duty of relevant government authorities to ensure compliance with building codes. "While we cannot construct fully earthquake-proof buildings due to high costs, we can at least make them earthquake-tolerant and minimise casualties," he said.

In Chattogram, the main concern is the lack of space for rescue due to the absence of emergency entry and exit routes in many buildings, he added.

Asked why the tilted buildings from the 2016 earthquake have not been demolished, the CDA chief engineer said the authority can only identify risky structures, not knock them down. Demolition is the responsibility of the Chattogram City Corporation.

"We have identified 100 risky buildings and submitted the list to CCC," he said.

Contacted, CCC Mayor Shahadat Hossain said he was not aware of the details. "I am speaking to my officials and will find out why the risky buildings have not yet been demolished," he said.