The Seoul Metropolitan Government has come under audit over allegations that it learned of missing rebar in the GTX-A Samsung Station section and reported it late to the Ministry of Land, Infrastructure and Transport. The city said it began an on-site inspection and reviewed reinforcement methods immediately after the Sigongsa's report, and reported to the government after completing procedures to ensure safety.
On the 16th, the Seoul Metropolitan Government released an explanatory document disclosing the column construction error identified during the construction of the underground integrated transfer center at Yeongdong-daero and the progress of follow-up measures. According to the city, Hyundai Engineering & Construction, during its own quality inspection in November last year, found that some columns on the fifth basement level near Samsung Station had been built differently from the design, and notified the city through the supervision team.
The Seoul Metropolitan Government said that after receiving the report, it conducted a site inspection with the supervision team and the Sigongsa and reviewed whether there were any issues with structural stability. The supervision team then prepared a column reinforcement plan and reported it to the city, which established a reinforcement implementation plan after consulting outside experts. Through March this year, 19 joint inspections by the city, the supervision team, and the Sigongsa were conducted, and consultations with outside experts, including members of the Seoul Construction Technology Review Committee, also took place.
The Sigongsa submitted a reinforcement construction plan in March. After confirming its applicability on site, the Seoul Metropolitan Government finalized the reinforcement plan and reported it sequentially to Korea National Railway and the Ministry of Land, Infrastructure and Transport (MOLIT) in April. MOLIT launched an audit of the city and Korea National Railway to determine whether there were any issues with the circumstances under which the city recognized the error last year but reported it only months later.
The Seoul Metropolitan Government said structural safety after reinforcement will exceed the original design standards. Expert structural calculations confirmed that, after reinforcement, axial load strength would be secured at a level higher than the original design standards. The reinforcement will add steel plates stronger than the existing rebar and apply fireproof coatings to prevent fire and corrosion. Hyundai Engineering & Construction will bear the additional construction cost of about 3 billion won.
The matter is also tied to the consolidation schedule of the GTX-A section connecting Seoul Station and Suseo Station. GTX-A opened first on the Suseo–Dongtan section and the Unjeong Jungang–Seoul Station section, and the 13.7-kilometer Seoul–Suseo section must follow to connect the line as one. Samsung Station, linked to the Yeongdong-daero integrated transfer center construction, has been under review for a no-stop pass-through approach for the time being.
The Seoul Metropolitan Government said, "We will establish structural safety measures and measures to prevent recurrence and work with the Ministry of Land, Infrastructure and Transport (MOLIT) to ensure there are no delays to the GTX-A Samsung Station no-stop pass-through schedule." It also said it would determine the cause of the construction error and the responsibility in the supervision and construction processes, and take action in accordance with relevant laws and regulations.