Seosomun Overpass Collapse: Failure to Ensure Safety of Inspectors

"Safety for Inspectors Tasked with Protecting Workers Was Inadequate"

Signs of Collapse Detected 12 Hours Prior...Were Preemptive Measures Taken?

Both Occupational Safety and Health Act and Serious Accidents Punishment Act Likely to Apply

The collapse of the Seosomun Overpass in Seoul, which resulted in three fatalities, is being analyzed as a consequence of inadequate safety measures for the “inspectors” responsible for conducting checks to ensure the safety of workers on site. Although demolition work had been halted due to concerns about a potential collapse, a work vehicle passed through the hazardous area below and was crushed by debris. It was also confirmed that inspectors were deployed at the site of cracks without the installation of additional support structures.

A 60-Year-Old Deteriorated Bridge... Cracks Detected 12 Hours Before the Collapse

On the 26th, at the demolition site of the Seosomun overpass in Seodaemun-gu, Seoul, the bridge deck collapsed, and firefighters are conducting rescue operations. Photo by Kang Jinhyung

According to a compilation of opinions from multiple industry and safety experts by The Asia Business Daily on May 27, the main cause of casualties in this accident was identified as insufficient preemptive safety measures for inspectors. Professor Hyungjun Ahn of the Department of Architectural Engineering at Konkuk University stated, “It was already such a dangerous site that demolition had been decided after receiving a D grade,” adding, “Before conducting a detailed safety inspection, the safety of the workers should have been secured, which was not done.”

At approximately 2:33 p.m. the previous day, the deck of the Seosomun Overpass in Seodaemun-gu, Seoul collapsed. The accident claimed the lives of a site manager in his 60s, a supervising inspector in his 60s, and an external expert in his 50s. Three others were injured and are receiving treatment.

The collapse occurred during a safety inspection. In the early morning of the accident, while cutting the slab (the concrete floor and ceiling structure), a level difference of about 2.9 cm subsidence was detected in the structure. Demolition was carried out by cutting the upper slab and the girder (the beams supporting the bridge and construction structure) and then lifting them all at once with a crane. Since trains pass under the demolition site during the day, work could only be performed during the early morning hours.

Work was halted, and approximately 12 hours later, the deck collapsed during a safety inspection. Choi Jinwoo, Director of the Civil Engineering Division at the Seoul Metropolitan Government Urban Infrastructure Headquarters, explained, “It is presumed that the collapse occurred when the girder broke in the middle.” The personnel who entered between the girders for inspection became the victims of the disaster.

Woncheol Choi, a special appointment professor at the Graduate School of Real Estate Convergence at Hanyang University, pointed out that there appeared to be no separate support structures or safety measures for inspectors at the site. He remarked, “It is very regrettable that the site manager or supervising inspector entered the site to check the problem without any measures in place,” and emphasized, “If a problem occurs during demolition, the area where collapse is feared should be reinforced with supports before starting the inspection.”

“Whether There Were Preemptive Safety Measures for Inspectors Must Be Examined”

A reconstructed diagram of the collapse process of the Seosomun Overpass in Seodaemun-gu, Seoul, based on the explanation from the fire department. Image generated by ChatGPT.

Several experts agreed that if signs of collapse such as subsidence of the bridge deck are detected, safety inspections must only be conducted after preemptive safety measures are taken. The investigation should determine whether appropriate checks were carried out prior to the safety inspection, and whether all necessary actions were taken for the inspectors deployed on site.

Professor Myungki Choi of the Korea Industrial Field Professors Association analyzed, “When the slab and girder are cut, they become separated from adjacent structures and lose their load-bearing capacity,” adding, “When inspectors climbed onto the aerial scaffolding (pipe structure), the increased load might have contributed to the collapse.” Six people were on the scaffolding, adding a minimum load of 438 kg (assuming an average adult male weight of 73 kg) to the cracked area.

Professor Choi also noted that the fatalities occurred beneath the collapsed bridge. CCTV footage capturing the moment of collapse shows a work vehicle traveling underneath the bridge, which was then crushed by debris. Although work had been suspended and a safety inspection was underway due to collapse concerns, vehicles were still able to pass through the area below. The driver in his 30s who was in the vehicle was rescued, but the supervising inspector at the scene died after being trapped by the debris and the vehicle.

Professor Choi stated, “The fact that fatalities occurred beneath the bridge being inspected is evidence of systematic inadequacy in safety measures for those conducting inspections,” adding, “If the deceased were in their 50s and 60s, they likely had 30 to 40 years of field experience, so I question whether there was complacency regarding safety. He also suggested, “It is possible that continued demolition work led to carelessness or that there was an attempt to rush the schedule.”

Both the Occupational Safety and Health Act and the Serious Accidents Punishment Act Likely to Be Applied

The Seoul Metropolitan Police Agency’s Metropolitan Investigation Unit and the Seoul Western District Prosecutors’ Office have each set up dedicated investigation teams and are speeding up the investigation. The Seoul Metropolitan Police’s special investigation team conducted a joint, detailed examination of the scene with the National Forensic Service and the Korea Occupational Safety and Health Agency from midnight to 4 a.m. to determine the cause of the accident.

Given that three people were killed, it is highly likely that both the Occupational Safety and Health Act and the Act on Punishment of Serious Accidents (Serious Accidents Punishment Act) will be applied. If it is found that necessary safety measures were not implemented, not only the on-site managers but also the executive management of the construction company could be held responsible. A police official stated, “Depending on the findings, the applicable legal provisions may vary, but as of now, it is expected that all relevant laws, including the Serious Accidents Punishment Act, will be applied.”

The Seoul Metropolitan Government is also unlikely to be free from responsibility. For 12 hours after the cracks were detected until the bridge collapsed, there was no access control on the road or sidewalk. Safety devices for pedestrians were also inadequate. The distance between the collapse site and the sidewalk was only a two-lane road, 5 to 6 meters wide, making it extremely close. At the time of the accident, there were no measures to restrict passage except for dust barriers and safety cones.

City to Provide Full Support to Bereaved Families... Follow-up Measures to Be Announced

On the 26th, at the Seosomun overpass demolition site in Seodaemun-gu, Seoul, the bridge deck collapsed, and firefighters are conducting rescue operations. Photo by Jin-Hyung Kang

The Seoul Metropolitan Government, under the leadership of Acting Mayor Kim Seongbo, has established a Disaster and Safety Countermeasures Headquarters and is comprehensively managing accident response, support for the bereaved families and injured, and site safety management in cooperation with related agencies. The city announced that it will provide living stabilization funds to the bereaved families and injured, along with welfare services and psychological counseling. Chunkeun Lim, Director of the Urban Infrastructure Headquarters, is scheduled to hold a briefing this afternoon to explain the circumstances of the accident and announce follow-up measures.

Meanwhile, the Seosomun Overpass, built in 1966, consisted of 18 piers connecting Chungjeongno Station and City Hall Station. It was 335 meters long and 14.9 meters wide. In March 2019, safety problems surfaced as pieces of concrete fell onto the road due to aging. After an inspection, the bridge was graded D, leading to the decision to demolish it. Demolition began in September last year and was scheduled to be completed early next month. The accident occurred when the demolition was about 89% complete.

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