Bridge Report Released, Cause of Collapse Still Unknown

The incident took place on 14th May, 2008, when what is now known as the F. T. Williams Highway or the West Basseterre Bypass Road was under construction.

St. Vincent and the Grenadines national, Allrick Toney (64) died as a result of the incident while Guyanese nationals Mortland Watterton and Ian ‘Shatta’ Warde were both injured.

The report dubbed, “Review of the Collapse of Formwork to Deck of Bridge No 4 on 14th May 2008” is dated “June 2008” but was only released last Wednesday by Permanent Secretary in the Public Works Department, following a joint press conference held by Prime Minister Denzil Douglas and Minister of Public Works, Dr. Earl Asim Martin.

The report – compiled by Halcrow Group Ltd – still leaves a plethora of questions in the public’s minds about the cause of the collapse as it was inconclusive.

“From our examination, various possibilities were looked at in order to determine potential reasons for the catastrophic failure. However, no conclusive failure mechanism has been identified, only a number of potential aspects that may have contributed to the failure, comprising temporary loading overstressing and supporting component, material failure and/or the stability/fixing of the acrow props.”

Elaborating on the possible points of failure which may have contributed to or may have caused the collapse of the bridge, the reports explains, “In examination of the prospect of the failure of the post shoring Acrow props, it was determined that the vertical capacity of the props was adequate to support the applied loading. However, it is possible that an Acrow prop (perhaps at a critical point) was not securely mounted, that the pins may not have been fitted properly or that the adjustment handle may have been loose. Any of these could have been overlooked in the formwork erection and could have started a chain reaction leading to the catastrophic collapse. Potentially this could have accounted for the loud noise heard immediately before the failure occurred.”

The report also names the quality of material used, as a possible contributing factor to the collapse.

“The Caribbean, because of price, traditionally imports timber of low grade that has not necessarily gone through the most rigorous quality control testing. In examining the broken yellow pine planks and timber on site after the event, judging from the frequency and size of knots, it was clear that the timber was not of the highest grade. It is thus possible that though a uniform member (beam) was calculated to have sufficient cross-sectional capacity to carry the applied point or uniform loads, a know located at a critically important point along the beam could have significantly reduced the load bearing capacity of the member and created a potential weak point. Again, this could account for the sudden failure mechanism of this particular collapse.”

Several other conceivable contributors to the collapse of the bridge were spelt out in the report, however, it stated unequivocally that, “With the available evidence, it has not been possible to conclude a definitive reason for the failure of the temporary works for Bridge 4.”

Meanwhile, MiyVue.com understands that one of the men injured during the collapse of the bridge, Watterton, has indicated that he suffers from a spinal injury and resulting complications. He has also indicated to this media house that he is unable to work and has to rely on social security benefits to take care of his family of four.

The other injured individual, MiyVue.com understands, has recovered from his injuries.

 


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