DST dehumidifies world’s longest bridge

Published 2013-11-25 in 

Seibu Giken DST subsidiary DST China is supplying a large number of dehumidifier units to the ongoing HZMB bridge project, which will link the cities of Hong Kong, Zhuhai City and Macao.

HZMB is an abbreviation of “Hong Kong/Zhuhai/Macao Bridge”. A link made up of bridges, underwater tunnels and artificial islands, designed to connect Hong Kong to Zhuhai City in the Guangdong Province and Macao is currently being constructed in China. These regions are currently divided by Lingdingyang, the Pearl River estuary which meets the sea here. This enormous project is expected to be complete by late 2016.

The total length of this link, coast to coast, will be around 35.6 km, making it the world’s longest structure made up of bridges, artificial islands and underwater tunnels. The main bridge will be a three-lane box girder bridge, 22.9 km long, which will run from the artificial island of Gongbei near Zhuhai to another artificial island west of Hong Kong.

There are stringent demands here in terms of design and construction: there are lots of flight routes, frequent typhoons and stringent environmental standards in place so as not to damage the delicate marine environment.

Dehumidification to help extend service life of bridge – to at least 120 years!
The HZMB bridge is being constructed with an estimated service life of at least 120 years.
Bridges with dehumidification solutions are nearly always box girder bridges, as they are known, where there is a cavity inside the bridge, between the carriageway and the lower part of the bridge. Electric cabling is installed here, and the steel cables which hold the bridge steady are mounted here. Condensation, and hence also corrosion, can occur inside this steel structure. Dry air removes moisture and subsequent problems such as rust and electrical faults, and so dehumidification saves a lot of money. Dehumidification also means that time does not have to be spent on maintenance work such as expensive, time-consuming application of corrosion protection paint to the inside of the bridge.

Reduced travelling times
The aim of this link is to reduce travelling times for goods transport and travel by car between the different regions. For instance, the journey between Zhuhai and Hong Kong International Airport is expected to be reduced from four hours to around 45 minutes! Of course, shorter travelling times will also provide major benefits for trade and industry and allow residents to commute between the cities.