Homes heedless of tremor risk

High-rise buildings as far as the eyes can see in Kathal Bagan in the capital and most of these structures are incapable of surviving a strong earthquake as they have not been retrofitted like the Tejgaon Fire Station, bellow.

The Tejgaon Fire Station building in the capital has been retrofitted and six more fire station buildings await the same to become earthquake resistant.

At least 300 garment factory buildings across the country and many office buildings of international organisations in Dhaka also have undergone the seismic retrofitting.

But, when it comes to people's homes, the picture is still very grim. Lack of awareness and high costs for the work are mainly to blame.

Earthquake retrofitting helps stiffening walls and it prevents buildings from collapsing during seismic activity. Bracing is accomplished by attaching structural-grade plywood tightly to the wall framing. The entire process costs up to 40 percent of the original spending for the building construction.

Actor, director Tauquir Ahmed is one of the few houseowners who had his house backfitted as part of earthquake preparedness.“A few years ago, there were frequent earthquakes. I spoke to my structural engineer and he suggested retrofitting my house. I did it accordingly and now I feel more secure" Tauquir told The Daily Star, adding, "I believe now our building does not shake as much during tremor."  

This measure is very crucial for Dhaka as experts say the city is highly vulnerable to earthquake disasters as preparedness to tackle them still remains somewhat average.

Bangladesh could be sitting atop an active megathrust fault, the same kind of geologic feature responsible for the 9.0 magnitude earthquake in Japan in 2011, a Geographic Information System (GIS) study found.

The findings of the study, published in the Nature Geoscience journal last year, mean that a 250km area may be spring-loaded with significant levels of tectonic strain that had been accumulating for more than 400 years.

If or when that energy is released, Dhaka could face catastrophic consequences as the sediments on which the city is built on might amplify the seismic waves. The calamity could be much worse because of the city's high population density and poorly constructed buildings, said experts.

A 7.5 magnitude earthquake might cause deaths of 88,000 people and collapse of 72,000 buildings in the capital, according to the findings of Comprehensive Disaster Management Programme, a joint project of the government and the UNDP.

On retrofitting buildings, Mehedi Ahmed Ansari of Buet's civil engineering department told The Daily Star, “We have to start detailed engineering assessment of the buildings in the city immediately.

"The readymade garment sector has done a tremendous job in this regard. People should also have to be motivated to know their building condition and take action on the basis of that," he said, adding that there were around four lakh buildings in Dhaka.

He also said it was not possible for the government to retrofit all the risky buildings alone. People need to come forward.

The Public Works Department (PWD) has taken up a project, titled "Urban Building Safety Project", to retrofit six fire stations and build three more. The project is being funded by the Japan International Cooperation Agency (Jica).

“Under this project, we will construct the headquarters of fire service in Mirpur where base isolation technology will be introduced for the first time in Bangladesh,” Syed Mahfuz Ahmad, the project director, said.

Meanwhile, Rajdhani Unnayan Kartripakkha (Rajuk) has also taken up a project, styled "Urban Resilience Project", to identify risky buildings in its first phase and to retrofit the most risky buildings in the second.

According to the Rajuk project, financed by the World Bank and scheduled to end in June 2020, preliminary vulnerability assessment would be done on schools, colleges, hospitals and important establishments like airports, Bangladesh Bank building and others.

The project plans to do rapid visual screening (RVS) of around 10 million square kilometres, said Abdul Latif Helaly, the project director.

Meanwhile, Bangladesh Housing and Building Research Institute along with Jica is developing a local technique of retrofitting for cost optimisation.

HBRI Director Abu Siddiq said, “We follow Japanese techniques for retrofitting in Bangladesh. But every country has some unique characteristics of building structures. With the fund of Jica, we are customising the retrofitting technique to make it suitable for Bangladesh.”

He said most of the four to five-storey buildings were built over 30 years ago and are made of bricks. These buildings usually are not earthquake resilient. “If the retrofitting cost is more than 50 percent of the total building cost, we suggest demolishing the building and construct it afresh.”

He said retrofitting enhances lifeline of a building by 100 years. 

“The issue is still not familiar to common people. The retrofitting issue is still heavily relying on donors' funds and government initiatives. House or apartment owners should come forward to assess their buildings to avoid earthquake hazards,” said Abdul Malek Sikdar, former deputy chief engineer of PWD.

He also said there were manpower and resource limitations and those should be overcome immediately.

Source: The Daily Star