Seosomun Overpass Skipped the Principle of Repair and Reinforcement Despite Urgent Demolition

It has been revealed that serious safety defects in the upper structure of Seosomun Overpass, which left six people dead or injured, were already identified more than seven months before the accident. However, full-scale repair and reinforcement were not carried out because the structure was scheduled for reconstruction after demolition.

According to the comprehensive report on the detailed safety inspection of Seosomun Overpass, obtained by The Financial News on the 2nd through the office of Park Min-kyu of the Democratic Party of Korea (DPK), the Korea Construction Quality Research Center (KCQR) and others conducted the inspection at the request of the Seobu Road Office, Seoul Metropolitan Government, from April 2023 to October 2025 and ultimately classified the bridge as safety grade D.

The reason was that a shortage of shear force in the coping section of the substructure, the structure that supports the bridge deck at the top of the pier, was judged to be a major defect in the safety assessment. A lack of shear force means the structure does not have enough capacity to withstand sliding or cutting forces generated under load. In such cases, the pier could even break apart.

Signs of damage were found throughout the bridge. Exposed rebar and spalling on the underside of the deck, corrosion of the S6 external tendons, and the condition of the falling-object prevention net were identified as key areas of concern. A damage survey also found 33 cases of exposed rebar and delamination on the underside of the deck, along with 18 cases of peeling and spalling. In the girders, 12 cases of exposed rebar and delamination and 24 cases of peeling, spalling and material separation were identified.

It was also pointed out that leaks could accelerate corrosion and aging of the bridge structure. The report said that leaks through the expansion joints, which absorb temperature changes and vibration in the bridge, were causing section loss on the underside of the deck, corrosion of bearings, and secondary damage to the abutments and piers. It added that if the leakage continues for a long time, the overall durability and safety of the structure could decline. In fact, 19 leak points at expansion joints and 63 traces of leakage in the substructure were found.

In its overall assessment, the inspection agency said, "Appropriate repairs for the damage that has occurred and reinforcement to address insufficient safety margins must be carried out." It added, "Until reconstruction, it would be preferable to install a falling-object prevention net and conduct regular inspections to prevent harm to people and vehicles, rather than carry out only short-term repairs."

However, experts said that even if a facility is scheduled for reconstruction, once serious defects are confirmed, the principle is to carry out repairs and reinforcement until the time of dismantling, not simply inspections.

Ahn Hong-seop, head of the Korean Society of Construction Safety, said, "The report used a softened expression for damage that had already gone beyond what inspections alone could resolve." He added, "We need to check whether anything was missed in the overall inspection process, the follow-up decisions by the management body, and the process of drawing up the demolition plan."

Some also argue that the first question should be whether local governments and local councils, which hold authority over manpower and budgets needed for safety, provided adequate support.

Choi Myung-gi, a professor with the Korean Industrial Field Instructors Group, explained, "Even when working-level departments draw up and submit budgets, they are often cut at the local government or council stage." He added, "As a result, reports sometimes propose only minimal repair and reinforcement measures, along with inspection-focused management, within the budget that can actually be secured."

Park Min-kyu said, "The chief engineer's overall assessment pointed to the need for regular inspections to prevent casualties, but a serious accident still occurred." He stressed, "We must thoroughly determine whether there were problems with on-site safety management for warning signs of danger and with the local government's oversight and supervision."



yesji@fnnews.com Kim Ye-ji Choi Seung-han Reporter