The Main Cause of the Gwangju Apartment Collapse Accident is 'Unauthorized Structural Modification'

Ministry of Land's Accident Investigation Committee Announces Cause Analysis

Unauthorized Changes in Floor Construction and Support Method Triggered Incident

Removal of Props and Poor Concrete Quality Also Contributed

[Asia Economy Honam Reporting Headquarters Reporter Park Jin-hyung] The main cause of the collapse accident at Hwajeong I-Park in Seo-gu, Gwangju Metropolitan City has been revealed to be an 'unauthorized structural modification.'

According to the Gwangju Police Agency on the 14th, the Ministry of Land, Infrastructure and Transport's Construction Accident Investigation Committee (Investigation Committee), composed of 12 experts, announced the results of the accident cause investigation conducted over two months starting January 12.

According to the Investigation Committee, the trigger for the disaster was the arbitrary change of the construction method and support system of the 39th-floor slab of the collapsed building, which differed from the original design drawings.

On the PIT floor below (where piping passes), the space was too narrow to install temporary supports (dongbari), so instead, seven concrete retaining walls weighing tens of tons were erected.

As a result, the floor slab, designed to withstand a load of 10.84 kN per 1㎡, could not bear the weight, which was 2.24 times heavier, and collapsed.

The problem was not the use of the deck plate method, an integrated formwork method, instead of the traditional method of pouring concrete into formwork, letting it harden, and then removing it.

The issue escalated because no 'structural review' was conducted despite the increased load caused by the installation of concrete retaining walls. The supervision team requested drawings from Hyundai Construction for structural review but reportedly never received them.

Another complex factor was the removal of temporary supports (dongbari) on the 37th and 38th floors, leaving the PIT floor slab to be supported alone. According to the standard construction specifications, at least three floors should have had dongbari installed, but this was not followed on site.

The concrete strength was also insufficient. Analysis of test specimens secured during a joint on-site inspection by the police and related agencies showed that most fell below 85% of the design standard strength.

Poor concrete quality caused reduced adhesion with rebar, leading to building stability issues.

Supervisory management failures also played a role. The Investigation Committee pointed out that the conditional requirements of the architectural review, such as cooperation between the original designer and related technical experts during construction, were not fulfilled, and the inspection checklist used by the supervision team on site lacked detailed inspection items for specific processes.

As measures to prevent recurrence, the Investigation Committee proposed ▲strengthening system enforcement ▲improving the supervision system ▲enhancing material and quality management ▲and reforming the subcontracting system.

Following the 'accident investigation opinion' from the Korea Occupational Safety and Health Agency under the Ministry of Employment and Labor, scientific cause analyses from official institutions are emerging one by one, accelerating the pace of the police investigation.

The police have expanded the investigation from 19 to 20 suspects on charges including causing the deaths of six workers at the new construction site on January 11 and are conducting investigations.

Among them, arrest warrants have been requested for five key suspects, including Hyundai Construction officials. Their pre-arrest suspect hearings (warrant hearings) are scheduled to be held at the Gwangju District Court at 11 a.m. on the 17th.

An official from the investigation headquarters stated, "A significant portion of the investigation has progressed after the accident response, and scientific cause analysis results are being derived. We are making every effort to clarify the charges so that those indicted can take responsibility according to their authority."

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