"Gwangju Public Library: Foreign Objects Illegally Inserted into Welded Joints... Collapse Occurred Just 4 Seconds After Joint Failure"

Ministry of Land, Infrastructure and Transport Accident Investigation Committee Announces Findings

The "Gwangju Public Library collapse accident," which claimed the lives of four workers in December last year, has been revealed as a classic man-made disaster caused by completely substandard welding that failed to meet even the most basic requirements. On July 30, the Accident Investigation Committee of the Ministry of Land, Infrastructure and Transport announced these findings from its investigation into the disaster.

Supporting Strength Dropped to a Quarter… Was Torn Off by the Weight of the Concrete

Visual Inspection of Weld Condition. Ministry of Land, Infrastructure and Transport

The investigation committee identified "defective welding" as the most direct cause of the collapse. On December 11 last year, at the Gwangju Public Library construction site in Chipyeong-dong, Seo-gu, Gwangju, workers were pouring concrete for the rooftop floor on top of the triangular steel frame supporting the roof. As the weight increased due to the piled concrete, the steel frame joints broke, causing both the roof level and the first floor to collapse, resulting in the deaths of four workers.

The investigation committee was composed of 11 experts with no ties to the project. They held 20 general meetings, conducted 5 on-site investigations, and carried out 2 hearings with relevant parties. They also performed inspections that examined internal defects without destroying the steel frames, as well as load analysis tests.

The investigation revealed that, according to the design plan, the groove between the two steel members was supposed to be filled completely with weld metal, known as "full penetration welding." To do this properly, the ends of the steel structures needed to be beveled to allow the weld metal to penetrate deeply inside.

This step was omitted at the actual site. There was also evidence that rebar had been inserted between the steel frames, which was then welded instead of using weld metal. Visual inspections and tests involving cutting through fracture surfaces all revealed the same structural flaws. As a result, the strength of the joints was only 22% to 31% of the design value.

Test results from corroding the cross-section of the steel frame joint at Gwangju Representative Library to inspect the interior. According to the design, the end of the steel frame should have been beveled and welded all the way inside, but it was confirmed that this step was skipped, and the weld included rebar inserted into the weld joint. Ministry of Land, Infrastructure and Transport

The collapse happened within seconds. As concrete was poured onto the rooftop floor, stress concentrated in one weld joining a column and an inclined steel member. This weld failed first, shifting the weight to the adjacent joint, which also failed to support the load. Subsequently, the joints on the opposite side fell off one after another. Within just four seconds from the initial failure, both the roof level and the first floor collapsed.

Opportunities to prevent the accident existed before, during, and after construction, but all were missed. The contractor failed to prepare detailed drawings specifying how the welding would be performed on site. Before work began, they did not verify whether the assigned workers had the necessary welding skills. Inspections of the completed welds were also inadequate.

The supervisory firm also failed to catch these issues. The investigation committee found that the supervisor did not properly review the incomplete detailed drawings, neglected to check both the skills of the welders and the results of post-work inspections. The investigation committee concluded that primary responsibility lay with both the contractor for poor construction and the supervisor for ineffective oversight.

"Business Suspension and Criminal Charges... Strict Measures Will Be Taken"

Accident Progression. Ministry of Land, Infrastructure and Transport

In a separate special inspection conducted in June by the Iksan Regional Office of Land and Infrastructure, further violations were found, including failure to implement a safety management plan, poor management of the quality control technician, and re-subcontracting construction to an unregistered company. It was once again confirmed that rebar had been inserted into the steel frame joints and the joints had been welded contrary to the design drawings.

The Iksan Regional Office plans to report the legal violations to the investigative authorities and impose penalty points and fines. The Ministry of Land, Infrastructure and Transport will also pursue suspending the business operations of the contractor and the supervisory firm. Materials related to the investigation will be handed over to the police and the Ministry of Employment and Labor so that they can investigate potential violations of industrial safety regulations and professional negligence resulting in death or injury.

The investigation committee recommended that the government specify the criteria and procedures for weld quality inspections more concretely in the official construction guidelines. It also proposed making it mandatory for supervisors to check both the welding work plan and the post-work inspection plan and to revise institutional rules so that the qualifications and capabilities of welders assigned to the site are verified in advance.

Choe Byeongjeong, head of the Accident Investigation Committee, said, "Together with various experts in the field, we made every effort to conduct an objective and scientific accident investigation. I hope that, based on the causes revealed and the recurrence prevention measures developed by our committee, similar accidents will never happen again."

This content was produced with the assistance of AI translation services.