By Jung Min-ho
The Yi Sun-sin Bridge ― the longest suspension bridge in Korea and the fourth-longest in the world ― was shut down temporarily Sunday because of safety concerns, only one and a half years after it opened.
Although the bridge was reopened the following day, public concerns over its safety remain.
According to the fire defense headquarters of South Jeolla Province Tuesday, it ordered the bridge that connects Yeosu and Gwangyang closed at around 7 p.m. Sunday after receiving a number of calls that the bridge was “shaking hard.”
The South Jeolla provincial government held an emergency meeting with construction experts at 1 a.m. Monday and concluded that tents, which were covering asphalt on each side of the bridge, were the cause of the swaying.
An official from the provincial government said that the tents were placed there temporarily to block the wind after pavement work was done on the bridge, noting that the asphalt needed to dry slowly so that it could reach the proper density.
“We believe the tents disturbed wind flow, causing the bridge to shake more than usual,” the official told The Korea Times. “Besides, suspension bridges are made to sway with the wind. As we removed all the tents, there is nothing now to worry about. We concluded that the bridge does not have a structural problem.”
He noted that experts later estimated later the bridge was swaying less than 90 centimeters. “But it was designed to withstand up to 2.6 meters without major problems,” he said.
After safety checks, the provincial government reopened the bridge at 8 p.m. Monday.
Despite the reopening and reassurances, questions linger about the soundness of the structure.
In fact, the provincial government had to re-do the pavement work after some cracks were found in the asphalt of the bridge about a year ago. It has done the job since June, blocking two lanes from Yeosu to Gwangyang.
Officials said that the cause of the cracks was the early opening of the bridge for Expo 2012 Yeosu Korea which ran from May to August in 2012.
Concerned about traffic inconvenience to tourists, provincial government officials temporarily opened the bridge before finishing the asphalt pavement to a standard thickness of five centimeters. Then they “officially” opened the bridge in February of last year.
Although suspension bridges are known to be better at withstanding earthquakes than bridges with more rigid construction, experts say that they can be unsafe in extreme weather conditions because they are relatively lightweight.
Suspension bridges with flaws in their support systems have been known to collapse. The original Tacoma Narrows Bridge, which was built in 1940, collapsed under strong winds four months after it opened.
Daelim Industrial was in charge of building the four-lane Yi Sun-sin Bridge, which has a total length of 2.26 kilometers. The length between the two main towers spans 1.54 kilometers.
After the shutdown, Rep. Woo Yoon-keun of the opposition New Politics Alliance for Democracy asked province Governor Lee Nak-yeon and Yeosu Mayor Ju Cheol-hyun to put extra effort into ensuring residents’ safety, saying that the “whole country is nervous” about such issues.
A series of fatal accidents, including the ferry Sewol sinking and the recent collapse of a ventilation grate, have jolted Koreans into thinking more about safety.