Ever heard of a gate that fetches water? That’s Kap Shui Mun. It is not just a place but a vital channel in Hong Kong.
Kap Shui Mun, or Throat Gates, sits between Lantau Island and Ma Wan. This channel is a key sea route. It links Victoria Harbour to the Pearl River. To the north, it meets Urmston Road.
Once known as kap shui mun, meaning “gate of fast-moving water”, it had a different feel. Locals associated the rapid currents with accidents. They thought it brought bad luck to ships. So, they changed the name. The new name sounds similar but means “water-fetching gate”. In Chinese culture, water symbolizes fortune and wealth.
The Kap Shui Mun Bridge spans this channel. It is a crucial part of Route 8. This bridge isn’t just any bridge. The Kap Shui Mun Bridge is one of the longest cable-stayed bridges that carries both road and rail traffic. The upper deck serves motor vehicles. The lower deck is for both vehicles and the MTR.
Completed in 1997, the Kap Shui Mun Bridge has a main span of 430 metres. That is around 1410 feet. Its total length reaches 750 metres. That is about 2460 feet. The bridge provides a vertical clearance of 47 metres. That is around 154 feet above sea level.
The total length of the Kap Shui Mun Bridge includes a 70-metre approach span on the Lantau side. Each back span has a column. This creates four 80-metre spans. Adding these to the main span totals 820 metres. The Ma Wan Viaduct is 503 metres long. It was built under the same contract as the Kap Shui Mun Bridge. The viaduct links the Kap Shui Mun Bridge to the Tsing Ma Bridge. Together, they form the Lantau Link. This link was built to provide access to Hong Kong’s new airport. The towers stand 150 metres tall. This height allows for the 47-metre navigation clearance.
Interestingly, the Kap Shui Mun Bridge is not symmetrical. The back span is less than half the main span. To balance this, engineers used a composite structure. The centre of the main span uses steel-concrete. This makes it lighter. The rest of the main span and the back spans are concrete. This design equalizes horizontal forces on the towers. It helps balance the bridge.
The lower deck’s design is unique. Because it carries both rail and road traffic, it uses a Vierendeel truss. This means no diagonal members are in the cross-section. Vehicles and trains pass through the openings.
The Wind and Structural Health Monitoring System closely monitors the Kap Shui Mun Bridge. This system also monitors the Tsing Ma Bridge and Ting Kau Bridge. The stay cables total 11 km in length. At midspan, vertical movement can reach 470 mm. Lateral movement can reach 155 mm. Longitudinal movement at Pier 1 can reach 320 mm.
In 2015, an incident occurred. A barge tried to pass under the bridge with a crane. The crane struck the bridge, damaging its underside. The impact triggered an alarm. Both road and rail traffic were shut down. The bridge was inspected. Only the inspection platform rails were damaged. The bridge’s structural integrity remained intact.
The Kap Shui Mun Bridge stands as a testament to engineering. It connects islands. It balances loads. It even survived a crane strike.