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    Volume 9 Issue 24| June 11, 2010|

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A Swaying City

Md Shamim-ul-alam

Photos: Star file

The June 1 tragedy when a five-storied building collapsed, killing 25 people, would have seemed to be a freak, one-time incident. But the city-dwellers were in for more shocks. On June 4, Friday, a seven-storied building tilted to one side. Thankfully there were no casualties. Then, on June 5, Saturday yet another four-storied building leaned to one side at Nakhalpara Samitybazar while one high-rise in Shantinagar developed cracks.

I got to the site of the tilted seven-storied building in Begunbari to see actually what happened. I moved along the muddy and narrow lane behind the Padma Garments and met two men sitting on a van in front of the building. One of them, called Tonu Mia, told me that initially the owner had had plans for four floors and the building has been constructed for two years. But this year the owner decided to build more floors which didn't prove congenial here. Mamun came all the way from Rampura to see this building when he heard of the tilt and he informed me that he had heard the owner of this building didn't ask for Rajuk's permission before constructing upper floors. Sub-Inspector Mojammel in Tejgaon Industrial Zone Police Station informed that Rajuk had been directed to demolish the building and a case has been filed against the owner. The owner has agreed to demolish the structure on his own.

But apart from gross flouting of building laws what were the technical reasons triggering such happenings? What happened in Begunbari can be partly attributed to the nature of the soil there. Clay forms the most part of the soil there and it is organic clay made from all kinds of waste pouring into that area. From an engineering viewpoint, clay of all kinds iss bad. Clay soil causes foundation movement, cracks by virtue of its peculiar property of expansion and contraction i.e. when it gets wet, it expands thereby creating a lifting force of 15,000 pounds per square feet. It can swell to 65% beyond its original size, with enough force to lift a home by several inches. Conversely, when clay soil dries out, it can shrink to 35% less than its original size. It is therefore recommended to keep the soil moisture as even as possible throughout the year to minimise the swelling and shrinking cycle of clay soil.

Experts blame the disaster on lack of proper foundation design. “A cliché in soil science is that foundation has no glory.” said Dr. Zoynul Abedin, Professor and Head of the department of Civil Engineering at Bangladesh University of Engineering and Technology (BUET). “Today people look forward to aesthetics of the building which can be showcased and represent social status and by doing so they ignore the very basics of foundation. They have most of their construction budget spent on beautification.”

Here, structural engineering and foundation engineering have taken a slightly different course, which are frequently mixed up. It's not about structural design or fault which causes a tilt but lack of proper foundation work. Many homeowners construct homes, buildings without any soil test, which determines the nature of soil and its loading capability. Should structural faults exist, they trigger collapse of rooftop or floor or beams or cracks on the wall.

Photos: Star file

However, cracks in building and tilting deserve different levels of attention. In some parts of the city, whenever any cracks on walls or roofs are discovered, people panic. Dr. Syed Fakhrul Ameen, professor at the Dept. of Civil Engineering, BUET, one of the members who went to probe the reported building in Shantinagar, said they found nothing serious there and described everything normal . He added that they already submitted a report based on their findings to PWD (Public Works Department). The building having cracks in Shantinagar was however, declared to be safe and its dwellers were told to return. The fact that developing cracks doesn't necessarily mean an impending collapse, sounds refreshing at this moment as news of recent tilts and the collapse disasters have caused a panic amongst city dwellers and scared the Civil Defense authorities.

Engr. Khondker Salahuddin, Chief Engineer at Rajuk, also opined that cracks are common phenomenon in any building and people should not panic unnecessarily. Commenting on the recently tilted structures, he blamed homeowners for their negligence and dishonesty. “None of the tilted buildings had approval from Rajuk nor did they have proper designs done and checked by professional engineers. When a plan comes to Rajuk for approval, it is checked and crosschecked by experts from relevant fields. What most people do is they just hire a group of construction workers under the lead of a construction foreman, who without any type of testing and design, comply with the owners' whims and build homes. The homeowners don't follow the building code,” he said.

Yet, it's all water under the bridge since such disasters are showing up every year and there are high casualties. What about the punitive measures regarding such incidents? How do property owners evade laws and raise constructions with such impunity? Has there been or is there any leniency in treating the convicted? Does Rajuk have limitations in punishing the guilty parties?

Engr. Salahuddin replied that existing laws are stringent enough and always under review. National building codes are also reviewed by the concerned authorities. A probe body comprising BUET experts has been formed to investigate recent disasters.

So, will we remain stuck in this grinding morass awaiting Apocalypse of our city? Professor Abedin said: “From my experience, I can say if soil condition is bad, proper foundation design should be stressed on. But whatever we say, at the end of the day, public consciousness and strict enforcement of existing laws is a sine qua non for a secure life.”



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