Broken Spine Ad Highlights Seongsu Bridge Gap, Calls for Deeper Investigation

A public service advertisement comparing a 9cm gap on Seoul's Seongsu Bridge south entrance ramp to a broken spine has sparked debate about the safety of the structure. The ad, created by Lee Je-seok Advertising Research Institute, features an X-ray image of a fractured spine placed on the concrete retaining wall where the gap has formed.

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You can only see it if you look inside

Beneath the image, the slogan "You can only see it if you look inside" urges a deeper inspection. The institute argues that the ramp, built on an embankment, may have experienced soil erosion due to prolonged vehicle vibrations, heavy rainfall, and aging drainage systems. They also pointed to nearby construction projects, including the GTX-A Han River undersea tunnel and the Dongbu Expressway undergroundization, as potential contributing factors.

Lee Je-seok, head of the institute, stated that while the issue is reported as a "gap or crack," the underlying cause is the ground sinking by about 9cm. He called for ground-penetrating radar (GPR) surveys and core drilling, with results disclosed to the public. The Seoul Metropolitan Government attributes the gap to differing foundation methods between the main bridge and the ramp's retaining wall, leading to long-term settlement differences. They maintain that precision safety inspections from 2016 to the present show the gap has remained stable at 89-90mm with no further settlement or deformation.

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If you look at the cause, the ground has sunk by about 9cm.

Despite the official assessment of structural safety, the city will conduct additional precision safety inspections with external expert consultations and install monitoring equipment to alleviate public anxiety. A comprehensive survey of all Han River bridge ramps will also be undertaken to identify similar gaps or safety concerns.

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We need to conduct ground-penetrating radar (GPR) surveys and core drilling and disclose the results to the public.