Tsing Ma Bridge

The Tsing Ma Bridge is a bridge in Hong Kong. It is the world's seventh-longest span suspension bridge. The bridge was named after two of the islands at its ends, namely Tsing Yi and Ma Wan . It has two decks and carries both road and rail traffic, which also makes it the largest suspension bridge of this type. The span is the largest of all bridges in the world carrying rail traffic.

Tsing Ma Bridge

Official name                  Tsing Ma Bridge

Carries                            6 lanes of roadway (upper), 2 MTR rail tracks, 2 lanes of roadway (lower)

Crosses                           Ma Wan Channel

Locale                             Ma Wan Island and Tsing Yi Island

Design                            Double-decked suspension bridge

Designer                         Mott MacDonald

Width                             41 metres (135 ft)

Longest span                  1,377 metres (4,518 ft)

Vertical clearance           62 metres (203 ft)

Opening date                 April 27, 1997

History

Construction of the bridge was carried out by a Costain / Mitsui / Trafalgar House joint venture. Construction work of the bridge began in May 1992 and ended in May 1997. It cost HK$7.2 billion. The Lantau Link, of which the bridge is an integral part, was opened on April 27, 1997. The ceremony was inaugurated by the former British Prime Minister Margaret Thatcher.

Test

The objectives of the wind tunnel studies were to demonstrate the safety of the structure under construction and once completed, both with respect to aerodynamic stability as well as the possible effects of extreme typhoon wind speeds. A further objective was to provide dynamic response data at several key locations to compare with full scale data from the ongoing monitoring program, conducted by the Highways Department of Hong Kong.

A 1 to 80 scale section model of the deck in the erection stage, and a 1 to 400 scale full aeroelastic model of the entire bridge were constructed. It is a Monte-Carlo simulation of the typhoon wind climate.

The full model was tested in different stages of construction in turbulent boundary layer flow, complete with the local topography in order to model the wind conditions at the site. The model tests identified critical stages of erection that allowed the construction schedule of the bridge to be tailored to avoid the typhoon season. The comparison of model test results and the full scale monitoring will assist engineers to better understand the behaviour of long span bridges in wind and to improve current design methods.