SAO releases one-year report on building collapse, cites four main causes
Investigations into the collapse of the new SAO office building found flaws in the design and construction, while state agencies have provided 129.86 million baht in preliminary compensation and assistance.
- The collapse began on the lower floors (1-4) when shear walls failed under the stress of earthquake tremors.
- Concrete samples taken from the building's shear walls were found to be below the required quality standard.
- The construction drawings did not comply with applicable laws, resulting in a building designed to withstand less force than legally required.
- The reinforcing bars connecting link beams to shear walls were shorter than legally required, creating weak connection points.
The State Audit Office of the Kingdom of Thailand (SAO) released, on March 20, 2026, a progress report on the collapse of the new SAO office building, which was under construction when earthquake tremors struck.
It summarised the findings of the fact-finding committee in three groups: state agencies and the administrative sector, academic institutions and scholars, and professional regulatory organisations, as well as the building inspection results from four engineering institutions (Chulalongkorn University, King Mongkut’s Institute of Technology, Ladkrabang, Kasetsart University, and King Mongkut’s University of Technology Thonburi).
The SAO stated that, according to the Prime Minister’s announcement of the inspection findings on June 30, 2025, deficiencies were found in the building’s design and construction methods in four areas, as follows:
- The collapse began in the lower part of the building, on floors 1-4, due to shear forces generated by the earthquake acting on the shear walls until failure occurred.
- The average test results of concrete samples taken from the shear walls were below the required standard.
- The detailed drawings used for construction did not comply with the applicable law, resulting in the building being able to withstand less force than required by law.
- The embedment length of the reinforcing bars at the connection points between the link beams and the shear walls was shorter than required by law, weakening those connection points.
The SAO added that the total amount of preliminary compensation and assistance provided by state agencies came to THB129.86 million.
At the same time, legal proceedings have been divided into four parts:
- At the Criminal Court stage, a total of 23 suspects, both individuals and juristic persons, have been indicted over allegations that the design, supervision and construction did not comply with the required standards, causing deaths, as well as jointly forging and using forged documents.
- The Department of Special Investigation (DSI) is pursuing a “nominee” case and has recommended prosecution to the public prosecutor. The prosecutor has already decided to indict. In addition, in the case of examining whether state officials were involved, the case file has already been sent to the Office of the National Anti-Corruption Commission.
- At the Office of the National Anti-Corruption Commission (Thailand) stage, the matter has been received from the DSI and investigating officers for examination. The SAO has already submitted documentary evidence to the Office of the National Anti-Corruption Commission as requested.
- The Comptroller General’s Department is examining compliance with the law on public procurement and supplies administration. The SAO has responded to queries, clarified the information, and submitted the relevant documentary evidence for that examination.
