Two of the three lanes on the Hong Kong-bound carriageway of the 5.5km Shenzhen Bay Bridge have to be closed for about three weeks to allow a snapped steel cable to be replaced.
The cable, with a diameter of about 160mm, was broken on Friday afternoon. It was one of six "external pre-stressed tendons."
Initial investigations showed rusting may have caused it to snap. The Highways Department said the broken wire posed no danger.
Structural engineer Ngai Hok-yan said a maintenance problem could have caused the rusting.
The bridge was jointly built by Shenzhen and Hong Kong. The main contractor of the Hong Kong section was Gammon-Skanska-MBEC Joint Venture. The maintenance and repair is the responsibility of a different company.
The Standard yesterday found that the maintenance and repair of the bridge is included in an HK$850 million contract called Management and Maintenance of High Speed Roads in New Territories West and Kowloon, and Roads in Hong Kong Port Area 2016-2022.
The contract was signed between the Highways Department and China Road and Bridge Corporation, a subsidiary of mainland company China Communications Construction. The six-year contract began on April 1, 2016, and will end on March 31, 2022.
The agreement mainly covers management and maintenance of the expressways in New Territories West and Kowloon as well as the public roads in the Hong Kong Port Area, including improvement works for related slopes, road structures, tunnels, landscape facilities and small-scale road.
According to an article published by Lau Ching-kwong, former head of the Civil Engineering Department on mainland academic journal Science and Technology Progress and Policy, the Highways Department requires contractors to conduct inspections of the bridge every six months when it approves the road maintenance contract.
The contractors need to inspect the surface condition 20 meters from the bridge structure to see if the bridge has obvious damage and they are responsible for immediate repair.
More detailed close-up inspections need to be carried out during regular inspections every two years.
During a press conference on Saturday, the Director of Highways, Jimmy Chan Pai-ming, said samples of the broken part of the tandem need to be taken to the laboratory for tests.
The last routine cable check was in September and an inspection about two weeks ago did not find any cable broken.