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An accident had happen on 28th Mei 2009 at approximately 5.00 p.m involving the collapse of a building structure. There were seven fatalities while three more were injured during the accident.
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The accident happened while demolition works were in progress for the redevelopment of supermarket and office complex. The demolition works using four excavators installed with hydraulic breakers and one excavator with shovel which were placed at the parking lot on the fourth floor.
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The collapsed building was built using 'flat plate prestressed concrete of post tensioning unbonded tendon' method. This method uses the tensile strength of the tendon to overcome the natural weakness of the concrete on compression when load is applied.
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The usage of this method is highly critical because of high energy stored in the tendon. This is dangerous especially when the opening were done unsafely on the slab. If the tension of the tendon is release, slab would be paralyzed and cannot sustain the load imposed. Tendon could also slash out of the slab if tendon were cut accidentally.
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| Suggestions: |
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| 1. |
The demolition works should follow requirement of laws and reference to the Standards and Code of Practice in relation to the demolition works should be made.
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Engineering survey should be carried out to identify method of construction of the building especially for complex structure.
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| 3. |
Risk Management and Health Hazard (HIRARC) on structure should be carried out before demolition activities starts.
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Method Statement should be provided to explain works that will be carried out including details of demolition works, type of machineries used and safety measures need to be taken.
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| 5. |
Building waste management should be done including providing suitable chute and to ensure building waste were manage properly and periodically to prevent excess burden on slab and other structure related.
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| 6. |
Professional engineer should prepare the structure design calculation by taking into account the strength, integrity and stability of the structure including temporary scaffold and imposed load.
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| 7. |
Demolition work should be supervised and monitored by expert or knowledgeable person in demolishing the structure.
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| 8. |
The employer must ensure all the information regarding the demolition works are passed on to the employees, parties involve and other person who may be affected under the activity.
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| 9. |
The employer should follow method of statement provided.
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| References : |
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Akta Keselamatan dan Kesihatan Pekerjaan 1994 |
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Akta Kilang dan Jentera 1967 |
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Peraturan-peraturan Kilang dan Jentera (Kendalian Bangunan dan Kerja-kerja Kejuruteraan) (Keselamatan) 1986 |
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Garis Panduan Bagi Keselamatan dan Kesihatan Awam di Tapak Pembinaan, Jabatan Keselamatan dan Kesihatan Pekerjaan, 2007 |
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Standard / Tata amalan: |
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a.
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MS 282, 1975: Code Of Practice For Building Operations Code |
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b.
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BS 6187 : 2000 : Code of Practice for Demolition |
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c.
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Code of Practice for Demolition of Buildings, 2004 (Hongkong) |
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d.
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Approved Code of Practice for Demolition (New Zealand) |
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e.
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CP 11 : 2002 : Code of Practice for Demolition |
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f.
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AS 2601 - 2001 : The Demolition of structure |
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