Rangs floor collapse calls for

sciei ific highrise demolition

TawfiqueAli

The latest incident of floor collapse of the Rangs Bhaban reminds the authorities of the necessity of following a scientific and safe method in demolishing any high-rise building.

Experts said the authorities have neither carried out any survey nor taken any safety precautions before going for demolition of the 22-storey building in the city.

As a consequence of the 'unplanned and unprofessional’ handling of the demolition work, several labourers were killed and manyi .injured when the floors collapsed Saturday night.

According to witnesses* account, part of the building’s 17th floor) caved in at about 9:45pm, resulting in collapse of all the subsequent floors downward to the 3rd floor.

The experts said the authorities consistently ignored, since the very beginning, all die warnings, precautions and suggestions for safe demolition of such a high-rise building.

They believe that excessive load of piled-up debris might have caused the accident.

Prof Jamilur Reza Chowdhury, an engineer and an expert in the field and vice-chancellor of Brae University, said the authorities should have taken adequate precautions and ensured engineering supervision considering lives of hundreds of labourers and other staff.

"It was a very unprofessional handling of a huge demolition work," Prof Chowdhury said. "The incidents manifest total lack of engineering supervision in the work."

Demolishing the upper 16 floors keeping the six at the bottom intact is really a difficult job, he said. "The authorities should have demonstrated adequate professionalism and taken more precautionary measures, which are evidently absent in this case."

In case of demolishing even an ordinary building, there must

be an approved methodical statement (demolition plan) on how the job will be carried out. But in case of Rangs Bhaban, demolition contractors were engaged without any plan, sources said.

Rajuk Chairman KAM Haroon could not be contacted for his version in this regard.

Sckandar Ali, a professor of civil engineering at Bangladesh University of Engineering and Technology (Buet), said normally

load-bearing capacity of a floor is 250 to 300 pounds per square foot. But in tliis case it seems that load of debris was much higher.

R a j d h a n i Unnayan Kartripakhha (Rajuk) started , demolishing interiors of the upper 16 floors of the 22-storey building on August 3, a day after the government won a legal battle in the Supreme Court in favour ofdismantli ng the floors.

But inadequate safely measures and lack of engineering

supervision in the demolition work resulted in the death of a day-labourer Sohrab Hossain, who fell off theT2th floor of the building while demolishing an inner wall on August 8.

Following the death of Sohrab, former chief engineer of Rajuk M Emdadul Islam cautioned about the possibilities of further accidents and causalities if the work was carried on with the conventional demolition method.

Islam, who is a fellow of the Institute of Demolition Engineers, UK, suggested controlled demolition (blasting with explosives) of the building.

Professor Sekandar Ali said that any demolition work must be carried out as per a plan and sequence prepared and supervised by engineers. He also said that labourers on the other hand should have insurance coverage.

President of the Institute of Architects Bangladesh (IAB) Mubasshar Hussain said the safe way was to knock down the floors one after another from the top removing instantly the debris of the preceding floor, instead of piling it up on the lower floors.

"Authorities should have explored other options like using explosives. Demolition is a highly technical job. But the demolition of Rangs Bhaban was being carried out as a mere labour-dependent job," he said.

"The disaster that have occurred manifests that the authorities did not have any demolition survey and plan," Husain said.

According to Bangladesh National Building Code (BNBC), all die demolition works shall be done on approval by a building official or an engineer 'having experience in demolition of similar magnitude.’ The code also asked for a detailed survey of the building to be demolished and of die surrounding buildings.

Shamsur Rahman, Rajuk authorised officer concerned, said the contractor of the demolition work carries out the work even at night to meet the deadline. But he could not say whether die contractor has permission to carry out demolition at night.

Rahman said that an engineering team of Rajuk and die contractor's own staff are supposed to do constant monitoring of the demolition work.

But site engineer of Six Star Ziaur Rahman said that usually no engineer from Rajuk or die contractor’s firm stays at the site during the night shift demolition work.

Raqib Hasan, an associate professor of civil engineering at Buet who is on the govern-ment-instituted three-member probe committee, said it would take time to ascertain the exact reason behind the collapse.