Probe finds substandard concrete and illegal design in State Audit Office building collapse; 23 indicted

The State Audit Office (SAO) has released an update on the collapse of its new headquarters building on March 28, 2025, saying investigators found multiple construction and design failures, including concrete strength below the required standard, non-compliant reinforcement detailing, and a building design not in line with legal requirements.

The SAO said it has been cooperating since the incident, providing information and documents to relevant committees and agencies, including fact-finding panels, parliamentary bodies, investigators from the Department of Special Investigation (DSI), the National Anti-Corruption Commission (NACC), and the Comptroller General’s Department.

Findings from the fact-finding investigation

According to the SAO, the collapse began in the lower part of the building—floors 1 to 4—after shear forces from the earthquake acted on the shear walls, leading to structural failure.

Key findings cited in the update include:

• Average test results from concrete core samples taken from the shear walls were below the specified threshold.
• Construction drawings and details used were not compliant with applicable law, reducing the building’s ability to resist forces to a level below what regulations require.
• The embedment/anchorage length of reinforcing steel at the connection between a link beam and the shear wall was shorter than required, weakening the joint.

Criminal proceedings

The SAO said investigators at Bang Sue Metropolitan Police Station concluded the case file, and prosecutors decided to indict 23 suspects—both legal entities and individuals—at the Criminal Court.

The charges cited include offences related to the design, supervision and construction of a building not following required standards or methods, allegedly causing danger to others resulting in death, as well as alleged offences related to forgery and the use of forged documents, alongside alleged breaches under the Building Control Act and the Public Procurement and Supplies Administration Act, and related regulations.

DSI and NACC actions

The SAO said the DSI has investigated alleged offences under the Foreign Business Act, and has forwarded its opinion to prosecutors. It added that other allegations—such as bid-rigging and complaints accusing state officials of misconduct—fall under the NACC’s mandate, and the DSI has forwarded related matters to the NACC.

The SAO said the NACC has asked it to submit relevant documents, and the SAO has already done so.

Comptroller General’s Department review

The SAO said the Comptroller General’s Department has been reviewing compliance with public procurement law and related regulations, and the SAO has responded to enquiries and submitted documents for that review.

The SAO said it remains ready to cooperate fully and has confidence in the justice process, adding it will act strictly in accordance with the law if facts show any state officials committed wrongdoing, to ensure transparency and maintain public confidence.