This bridge also carries the highest daily traffic in Hong Kong and the largest number of container trucks between Mainland China and the container port in Hong Kong. It is a six lane bridge built in 1988 with a total length of 3864 ft and with main spans of 1470 ft and 1560 ft.
Driving across the bridge, one is struck by the hundreds of container ships waiting to enter the port. Also, by the distinctive yellow on the steel anchorages at the top of the towers and on the steel girder superstructure.
Cable-Stayed Bridges - Ting Kau Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.
I don't think the extra cables from the main towers have much to do with wind loads. They are mainly there because ANY cable-stayed bridge with more than two towers requires additional stiffening to be effective. The two end towers are stiffened because their end cables can be anchored to ground. However, the centre tower's cables are only connected to flexible bridge deck, and hence do nothing to stiffen the tower - and if the tower is not stiff, the cables themselves are less effective.
ReplyDeleteThe Ting Kau design is one solution to this problem. Another is to stiffen the towers (see the Rion-Antirion bridge where each tower has four rather than two legs, this approach can also be seen on the Lake Maracaibo viaduct and the Millau Viaduct), or to stiffen the deck. You can also add additional intermediate supports (the two Oakland Bay suspension bridges, with their intermediate anchorage, show a similar solution for a different type of bridge). There are a number of other cable-related solutions such as tying the heads of the pylons together.
Michel Virlogeux's paper "Bridges with Multiple Cable-stayed Spans" (2001) provides much more detail.
PS: obviously I am talking about the extra cables from tower to tower here, not the transverse cables at each tower!
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