At the site of the bridge deck collapse on the Seoul-Sejong Expressway construction project in Ansan, Gyeonggi Province, where 10 casualties occurred, police, the National Forensic Service, the Korea Occupational Safety and Health Agency, the National Disaster and Safety Research Institute, and the Korea Land and Geospatial Informatix Corporation are conducting a joint investigation to determine the cause of the accident on Feb. /Courtesy of Yonhap News Agency

The collapse of the bridge deck structure at the construction site of the Seoul-Sejong Expressway in Anseong, which resulted in 10 fatalities, appears to have occurred while operating heavy equipment without thorough prior review.

According to police on the 23rd, the investigation team of the South Gyeonggi Provincial Police Agency received an assessment from the National Forensic Service stating that "the launcher became unstable and toppled over the DR girder without a structural review for the back launching operation."

The accident occurred during the process of extracting the beam launcher, a device used to lift and install girders (beams supporting the bridge deck). This is known as the 'back launching' operation. The beam launcher, which moves forward as a 'forward type,' travels over girders resting on piers instead of rails after a certain distance. It is said that during the back launching, it is unavoidable to touch the girders.

Given that the weight of the beam launcher reaches 400 tons, a 'structural review' was necessary to determine if the structure could withstand the load, but it appears that such a process was not undertaken in this incident. The police plan to continue investigations based on the assessment results.

On Feb. 25 at about 9:49 a.m., a girder collapsed at the construction site of the Cheongnyongcheon Bridge in section 9 of the Seoul-Sejong Expressway from Cheonan to Anseong, resulting in the deaths of 4 workers and injuries to 6 others.