Concerns are mounting over the safety of Seoul's aging bridges and infrastructure following the collapse of the Seosomun Overpass. With 1 in 10 bridges in Seoul having passed the 50-year mark since construction, and major infrastructure such as retaining walls, embankments, and pipelines also aging rapidly, experts say systematic maintenance measures beyond safety inspections are needed.
According to the Seoul Institute on Wednesday, the average service life of Seoul's 746 bridges as of last year was 33.8 years, 2.8 times the national average bridge service life of about 12 years. Of these, 326 bridges, or 43.7% of the total, were more than 30 years old. Bridges over 40 years old numbered 155 (20.8%), while those over 50 years totaled 66 (8.9%).
Seoul also has a high reliance on bridges. The city's bridge density is 1.21 per square kilometer, more than triple the national average of 0.36. Considering that the average commuting distance for citizens is about 18 kilometers, many residents use multiple bridges or pass beneath them during their commute. The structure means that any bridge accident inevitably leads to substantial casualties and property damage.
The aging is not limited to bridges. Among Seoul's facilities, the average service life of cut slopes, retaining walls, embankments, and pipelines has already surpassed 30 years. Cut slopes had the longest average at 44.3 years, while retaining walls (43.1 years) and embankments (36.3 years) also showed clear signs of aging. As infrastructure across the city enters the aging stage simultaneously, concerns are emerging that problems with specific facilities could escalate into safety risks across the city's overall functions.
The issue is that the management system remains centered on safety inspections. The current system evaluates facility conditions on a scale from A to E, but the post-inspection repair, reinforcement, and maintenance processes often depend on the judgment and capacity of the managing entity. Detailed safety inspection reports for large bridges run to hundreds of pages, but it is difficult to grasp at a glance the extent of damage, the speed of progression, and the level of risk. Damage recording methods also vary across reports, making it time-consuming to compare facilities or prioritize repairs.
In particular, identifying the speed of damage progression requires analyzing data accumulated since construction or repair work over time, but the current structure requires individually reviewing vast reports to organize information. Critics also point out that responsibility for managing facilities is divided among the Seoul Metropolitan Government, district offices, and public agencies, limiting comprehensive management of aging infrastructure.
The Seosomun Overpass accident is cited as a case that exposed this management gap. Built in 1966, the Seosomun Overpass received a D grade in a detailed safety inspection in 2019, requiring urgent repair and reinforcement, but demolition has not been completed for more than six years. Demolition work began last year, but operations were limited to three hours each dawn due to railway operations, causing process delays. Analysts say risk management burdens grew during this process.
The Seoul Metropolitan Government will conduct special inspections of 984 public and private construction sites from June 1 through the end of July, and will also carry out emergency safety inspections of 27 C-grade overpasses and bridges that require continuous repair and reinforcement. If defects are found, additional detailed safety inspections will be conducted to prepare repair and reinforcement measures.
"After detailed inspections and safety diagnoses, we need to specify measures to address damage and ensure that repairs are not delayed by budget or administrative procedures," said Lee Ki-se, a research fellow at the Infrastructure Technology Research Office of the Seoul Institute.
