The Kap Shui Mun Bridge (KSMB) in Hong Kong, part of Lantau Link of Route 8, is one of the longest cable-stayed bridges in the world that transports both road and railway traffic, with the upper deck used for motor vehicles and the lower deck used for both vehicles and the MTR. It has a main span of and an overall length of . It spans the Kap Shui Mun marine channel between Ma Wan and Lantau and has a vertical clearance of above sea level. The bridge was completed in 1997. Structural information The total length of the Kap Shui Mun Bridge includes a approach span on the Lantau side. There is a column in each of the back spans of the cable stayed bridge, making four spans, adding to the main span. This makes the total length . The Ma Wan Viaduct was constructed under the same contract as the KSMB. The viaduct connects the KSMB to the Tsing Ma Bridge, forming the Lantau Link, which was built to provide access to the new airport. The navigation clearance of is part of the reason that the H-shaped towers are tall. The Kap Shui Mun Bridge is not symmetrical, in that the back span length (two spans) is less than half of the main span length (which would be ). To provide the balance that symmetry will normally provide, part of the bridge has a composite structure. The center of the main span uses a steel-concrete composite to make the structure lighter. The back spans and the rest of the main span are concrete. Using the lighter steel cross section in the majority of the main span serves to equalize the horizontal forces on the towers and balance the bridge. Because the lower deck carries both rail and traffic, the cross section is designed as a Vierendeel truss. This means that there are no diagonal members in the cross section and that vehicles and rail cars drive through the openings provided by the Vierendeel design. Along with the Tsing Ma Bridge and Ting Kau Bridge, it is closely monitored by the Wind and Structural Health Monitoring System (WASHMS). Concrete strength of towers: Grade 50/20 or 50MPa Crane strike The bridge has a height restriction of 41 metres for vessels passing underneath. On 23 October 2015, a barge attempted to pass under the bridge with a broken-down crane that could