Fatal collapse of under-construction Bangkok bridge a stark reminder of safe working procedures

The collapse of an under-construction bridge in Bangkok, which killed two and injured several more, has sent a stark reminder of the need to follow safe working principles in all phases of a project.

On the evening of 10 July a segment of the elevated road in the Lat Krabang district of Thailand’s capital city collapsed along with the construction girder being used to build it. Two fatalities have been reported; that of the engineer overseeing the works and one of the construction workers on the project. At least 17 more were sent to hospital with injuries while at least eight cars and four motorbikes were crushed.

The structure in question is an elevated viaduct being constructed along the central island of the Lat Krabang Road, 20m above ground level. The structure is to be 2.2km long and carry four lanes of traffic.

It is a project being carried out on behalf of the Bangkok local authority at a cost of 1.66bn Thai Baht (£37M). It is being built by a joint venture between Tharawan Construction and Napa Construction. It was due to complete in 2024.

Construction plans for the collapsed bridge

The failure occurred on the most recently installed 500m section of the bridge. The construction girder collapsed simultaneously, causing widespread damage along the road.

In the aftermath of the incident, speculation mounted as to the cause. Bangkok governor Chadchart Sittipunt visited the site and said that, while it is too early to determine the fault, force majeure was not the cause.

According to Thai news organisation Khaosod, Sittipunt added: “This should not have happened during the construction process; anomalies may occur after the foundation is built deep into the sand layer. It is assumed that this was caused by construction instability. We expect the section where the pole is broken to be overweight.”

He added that someone would be held accountable for the failure.

Deputy governor Wisanu Subsompon, who also attended the site of the incident, suggested that the cause may have been a crane malfunction.

An investigation has been launched and it is expected that it could take up to a week to clear the debris and return the road into operation.

While the cause remains unknown, the incident has sent a stark reminder of the need to follow strict procedures during all phases of a project, especially a major one being constructed in a populated area.

“It’s too early to say what happened,” chair of UK Bridges Board Hazel McDonald told NCE. “The first place that is likely to be looked at is whether the site supervision and design for the temporary load cases was suitable and procedures followed.”

Independent bridge consultant Richard Fish added: “This is yet another serious collapse and it has to be hoped that there will be a thorough investigation into the causes which should be widely reported.

“It looks as if there could be a number of areas to look into, from permanent and temporary works design to construction techniques and workmanship. Only by learning from events such as this can we have the confidence that nothing similar can happen again.”

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