DemolitionSafety Seoul TemporaryWorks BridgeEngineering

Seoul overpass collapse kills three during demolition inspection

May, 26, 2026
Bridges Bridge Design Structural Failures News On Natural Disasters / Failures
South Korea
Authored by: TheCivilEngineer.org

*Emergency teams inspect the collapsed section of the Seosomun overpass during demolition works in central Seoul. Source: 1news (image by Choi Jae-gu/Yonhap via AP)*

A section of the Seosomun Overpass in central Seoul collapsed during demolition work, killing three people and injuring three others. The structure, built in 1966, was being dismantled because of safety concerns linked to its ageing condition. The collapse occurred while officials and a private-sector expert were carrying out a safety inspection after workers had earlier detected signs of instability.

According to officials, demolition activity had been suspended after part of the structure showed movement while concrete slabs were being cut. During the subsequent inspection, a section of the bridge deck suddenly gave way, causing debris and structural elements to fall onto people and vehicles below. Emergency crews sealed off the area and began rescue operations as broken concrete slabs and twisted steel members remained suspended around the damaged section.

Unlike a completed structure, a bridge under demolition no longer behaves according to its original design assumptions. Load paths can change as deck slabs, beams, bracing elements and supports are removed. If temporary stability measures are not continuously checked, even a small change in geometry, support condition or load distribution can contribute to a sudden collapse.

Debris from the overpass collapse affected nearby railway infrastructure, causing transport disruption and safety concerns. Source: 1news (image by Choi Jae-gu/Yonhap via AP)

This risk becomes more critical in older bridges, where deterioration, corrosion, fatigue and undocumented repairs may reduce residual capacity. The Seosomun Overpass had been in service for around six decades. During demolition, engineers must therefore consider not only the original structural system, but also hidden defects, weakened connections and the effects of long-term ageing.

The collapse also disrupted nearby rail operations after debris fell onto railway tracks and affected railway infrastructure. This shows how demolition failures in dense urban environments can quickly become multi-infrastructure incidents, affecting roads, railways, emergency access and public safety at the same time.

The Seoul accident underlines the need for strict demolition sequencing, real-time monitoring and clear exclusion zones during inspection and removal work. Safety inspections are essential, but inspectors should not be exposed to unstable structural zones unless temporary supports, access routes and emergency procedures have been fully secured.

For ageing bridges in busy cities, demolition should be treated as an engineered temporary works project, not simply as the reverse of construction. Each stage requires structural checks, load redistribution assessment, monitoring of deflections and a clear understanding of how partially dismantled members will behave.

Sources: koreatimes.co.kr, reuters.com, www.1news.co.nz