Five floors of the nine-storey garment building were being constructed while different garment machinery were in full operation, the report said adding, "The bond of reinforced concrete could not be developed properly for the vibration of these machinery."

Shafi Uddin Sarkar, chairman of research and study cell of IDEB, presented the report at a roundtable discussion arranged at IDEB Bhaban in the city yesterday.

At least 61 garment workers died in the country's deadliest building collapse in Savar on April 11.

"Examining the rubble of the collapsed factory, we found that cement was not properly attached to rod. And instead of stone, sand was used more, raising the probability of the collapse," Sarkar observed.

Besides, the garment building was overloaded with machinery and other equipment, making it another reason for the building to come down, he added.

The report strongly recommends installing vibration-generating heavy and light machinery on the land under a shade instead of inside the multi-storey factories.

It also suggests not constructing upper floors while production is on in the lower ones,just as it happened in the case of Spectrum Sweaters Ltd.

Prof Emazuddin Ahmed, Dr Serajul Islam Choudhury, Prof Nazrul Islam, President of Bangladesh Economic Association Dr Qazi Kholiquzzaman Ahmad, noted economist Dr Atiur Rahman, Rajdhani Unnayan Kartripakkha (Rajuk) Chief Engineer Md Emdadul Islam, IDEB President Rafiqul Islam Bhuiyan and General Secretary Kazi Nazrul Islam, among others, spoke at the discussion.