The scene at the demolition site of the Seosomun Overpass in Seodaemun-gu, Seoul, where a collapse accident occurred around 2:32 PM on the 26th. Fire authorities are checking for additional casualties. [Photo = Yonhap News]A portion of the structure at the demolition site of the Seosomun Overpass, a representative aged infrastructure in downtown Seoul, collapsed. The collapse occurred during demolition work on a structure that had been designated for demolition after receiving a Grade D rating in a detailed safety inspection.

While the cause of the accident is still under investigation, it is evolving beyond a simple construction site accident to expose safety management issues in the process of dismantling aged infrastructure.

According to the police and fire authorities, a portion of the overpass structure collapsed around 2:30 PM on the 26th at the Seosomun Overpass demolition site in Migeun-dong, Seodaemun-gu, Seoul.

Immediately following the accident, police and fire services cordoned off the area and began rescue operations. The fire department, having received the report around 2:33 PM, dispatched units and issued a Level 1 response.

A cargo truck was crushed at the site, and at least six people (one fatality), including workers and vehicle occupants, are reported to have been affected. Some of the injured have been rescued and transported to nearby hospitals.

The impact of the accident also affected railway operations. Korea Railroad Corporation suspended train services on the section between Seoul Station and Sinchon Station, which passes under the overpass. The accident at the downtown overpass demolition site has led not only to road closures but also to the suspension of train services.

Overpass Demolished Due to Danger, Accident Occurs During Demolition

The Seosomun Overpass had served as a vital traffic artery in downtown Seoul for 59 years since its completion in 1966. However, it was deemed no longer able to guarantee citizen safety after receiving a Grade D rating in a detailed safety inspection. The Seoul Metropolitan Government stated that structural damage had repeatedly occurred, including concrete delamination of piers in 2019, deck collapse in 2021, and beam damage in 2024.

The Seoul Metropolitan Government began full-scale demolition work on the Seosomun Overpass on September 21st of last year, closing it off completely from midnight. The demolition was originally planned to be completed by May 2026, followed by new construction, with completion scheduled for February 2028.

The problem lies precisely at this point. The Seosomun Overpass was a structure designated for demolition due to its hazardous condition. Therefore, the demolition process requires a higher level of pre-emptive safety planning and site control than ordinary construction.

The demolition sequence, load distribution, worker positions, equipment placement, control of vehicles and trains below, and the securing of emergency evacuation routes are all subjects that will inevitably be investigated.

The Dangers of Dismantling Aged Urban Infrastructure

Demolishing aged overpasses is not simply a matter of breaking down structures. Old structures may differ from their original design drawings in their actual state of damage, and factors such as reduced concrete strength, rebar corrosion, and beam damage can act in combination.

For this reason, if the load flow changes unexpectedly during demolition, parts of the structure can suddenly collapse.

The Seosomun Overpass was already a structure that had received a Grade D rating. A Grade D rating indicates that damage to major members and structural risks have been identified.

Therefore, the core issue of this accident is not "why was it demolished?" The core issue is "was the risk adequately controlled during the demolition of a structure whose risks were identified?"

The fact that the accident site was in the heart of downtown Seoul, with both road and rail functions intertwined beneath the overpass, further exacerbates the situation. It was not an accident that could be contained within the construction site itself.

Indeed, immediately after the accident, traffic around the overpass was controlled, and train services between Seoul Station and Sinchon Station were suspended. This incident once again demonstrated that an accident involving urban infrastructure can quickly lead to widespread chaos in the entire transportation network, not just at a single point of collapse.

The Remaining Question is Responsibility for Safety Management

The questions that remain are clear.

First, were the actual construction methods sufficiently reflective of the structure's damage status prior to demolition?

Second, was the prior review of load changes and potential collapse in the work areas appropriate?

Third, why were workers and vehicles within the danger radius?

Fourth, to what extent does the responsibility for site safety management lie with the Seoul Metropolitan Government and the construction and supervision entities?

The cause of the accident is expected to be determined through investigations by the police, fire department, and relevant agencies. However, based on the facts confirmed so far, it is difficult to categorize this accident as merely an "unforeseen incident during the demolition of an aged overpass."

The Seosomun Overpass was a structure demolished due to its hazardous condition. If so, it is imperative to re-examine whether the demolition process itself was sufficiently safe to protect citizens and workers.

Cities must eventually remove their aging infrastructure. However, if the process of demolishing a dangerous structure creates another danger, it is not a matter of construction management but a problem of urban safety administration.

The Seosomun Overpass collapse accident leaves one question. Was the demolition project, initiated due to risks, adequately managing those risks?