Two steel samples collected from debris of a collapsed building under construction in Bangkok have been found to be substandard, according to government sources. The 33-story structure collapsed on March 28 after a 7.7 magnitude earthquake dealt significant damage across Myanmar and Thailand, killing 18 people.

The building collapse has resulted in a raging controversy since no other high-rise structures in Bangkok, which is 1,000 km from the quake epicenter in Myanmar, has been seriously affected. More than 2,000 people have died in Myanmar as a result of the quake so far. The Red Cross has also flagged concerns that some of Myanmar’s dams may have been damaged but there are no confirmed reports of breaches.

The nonprofit Thai Iron and Steel Institute is examining seven samples of 32-mm, 25-mm, 20-mm, 16-mm, and 12-mm deformed steel bars, wire ropes and steel bars collected from the wreckage by an official team led by Industry Minister Akanat Promphan.

Thitipas Chotedechachainan, head of the technical investigation team, said that 32-mm deformed steel bars failed to meet the force-receiving value standard, while 20-mm bars failed to meet the mass-per-m standard.

Bangkok officials display steel samples taken from the wreckage of the collapsed building.
Photo courtesy Bangkok Metropolitan Administration

Thailand’s government has ordered an investigation on the design and structural integrity of the building being constructed by the China Railway Number 10 Engineering Group, a Chinese government entity. The project, commissioned by the State Audit Office, is jointly owned by that company and Italian-Thai Development Plc.

The Bangkok building controversy took a dramatic turn as police arrested four Chinese citizens trying to steal 32 documents from the debris following the earthquake, according to Nopasin Poolswat, deputy commissioner of the Metropolitan Police Bureau. The arrested individuals said they were trying to retrieve documents for making an insurance claim.

Amorn Pimarnmas, president of the Structural Engineers Association of Thailand, said Bangkok's soft soil may have also played a part in the building's collapse, as it can amplify ground motions by three or four times.

“However, there are other assumptions such as [concrete and reinforcement] quality and some irregularity in [the] structural system. These remain to be investigated in detail,” he said.

The authorities will also examine the method of construction in the $58-million project and whether efforts were made to make it earthquake resistant.

Christian Málaga-Chuquitaype, a senior lecturer in earthquake engineering at Imperial College London, who saw a video of the collapse and the wreckage, said it appears that a flat-slab construction process was being used—which is no longer recommended in earthquake-prone areas. “A flat slab system is a way of constructing buildings where floors are made to rest directly on columns, without using beams,” he told the BBC.

“Imagine a table supported only by legs, with no extra horizontal supports underneath. ... While this design has cost and architectural advantages, it performs poorly during earthquakes, often failing in a brittle and sudden, almost explosive, manner,” he added.

The collapse raised questions about the quality of government oversight for construction projects. 

Mana Nimitmongkol, president of the Anti-corruption Organisation of Thailand, said that the State Audit Office, which commissioned the project, was preparing to cancel it last January due to the contractor’s intermittent work stoppages in the early stages followed by significant delays.