The government has launched an investigation to determine the cause of the collapse of the 30-storey building at the centre of city rescue efforts following Friday's quake.
Critics have questioned the standards of a Chinese contractor involved, and raised concerns over the quality of steel and building materials used. An investigation team from the Ministry of Industry has collected samples of construction materials from the site of the collapsed State Audit Office (SAO) building in Chatuchak district, said Pongpol Yodmuangcharoen, secretary to Industry Minister Akanat Promphan, on Sunday.
The team is focusing on the quality of steel bars used in fortifying concrete polls, beams and foundation structures in particular, as substandard steel bars could have led to the collapse, said Mr Pongpol.
Substandard steel bars normally break, rather than bending to absorb powerful forces released by an earthquake, he added.
The ministry has recently taken legal action against up to seven companies producing and selling steel. They were all joint ventures of Thai and foreign companies, he said. The factories were closed after they were found to have produced and distributed substandard steel bars, which could have posed a threat to public safety, he said.
Deputy Prime Minister Anutin Charnvirakul, in charge of the government's rescue operation at the site, meanwhile, said an investigation is underway to first determine whether the design met standards. It would have to be earthquake-resistant as required under law. If the design turns out to be fine, the probe will then focus on other processes involved, he said.
Mr Anutin, also interior minister, insisted both the Thai and Chinese companies in the joint venture comprising Italian-Thai Development Plc and a subsidiary of China Railway No.10 Engineering Group, which was erecting the building, will be fully held accountable for the collapse and its consequences.
Since the SAO building was the only one in Bangkok which fell when the earthquake struck central Myanmar, with shockwaves sent to Bangkok, Mr Anutin said he believed any problems with the building would be identified and pinpointed.
In response to media reports about a group of men caught in action at the site, currently declared off-limits to outsiders, Mr Anutin said the probe committee would look into the matter. The men were said to have fled with document files. The panel, comprising senior engineers from Department of Public Works and Town and Country Planning and other experts, expects to take a week to probe the collapse, he said.
Meanwhile, Bang Sue police on Sunday detained for questioning five Chinese nationals and one Thai interpreter and seized 37 document files for inspection.
Tipped off by someone who witnessed the suspicious presence of these people at a temporary office on the SAO building premises, police rushed to the scene but the group had already left. The only person they met was a Chinese national who identified himself as Liu Yang, director of the project.
He provided police information about the six people, who were then summoned to meet investigators. They reported themselves to authorities and came with the document files in question, which were handed over to the police.
Mr Anutin on Sunday welcomed Han Zhiqiang, the Chinese ambassador to Thailand, who asked him for permission to lead a group of Chinese disaster management experts to visit the Chatuchak rescue site. The Chinese experts found no need to offer additional advice as the Thai team working on site appeared knowledgeable of rescue operations, said Mr Anutin.
In another development, the SAO on Sunday responded to questions about its project. The office said it strictly adhered to regulations in finding an architectural designer, contractor and inspector.
