Tsing Ma Bridge

Tags

Bridge, Bridges, Civil Engineering, Construction, Dongguan, Engineering, General contractor, Hong Kong, Humber Bridge, Kap Shui Mun Bridge, Technology, Tsing Ma Bridge, Tsing Yi

The Tsing Ma Bridge, which spans 1377m across the busy Ma Wan Channel, is the second longest bridge in the world after the Humber Bridge in Britain. However, it is the longest bridge that carries both motorway and railway.

There are Five Major Components
in the Construction of the Tsing Ma Bridge:

1. Foundations and the construction of the bridge tower – one tower located on Tsing Yi side and the other on a man-made island 120 m from the coast of Ma Wan Island. Both towers are 206m above sea level and founded on relatively shallow bedrock. The towers are two-legged with trusses at intervals, in the form of portal beam design. The legs were constructed with high-strength concrete of 100 MPa strength, using a slipform system in a continuous operation.

2. Anchorages – the pulling forces in the main suspension cables is taken up by large gravity anchorages located at both ends of the bridge. They are massive concrete structures deeply seated on bedrock on the landside of Tsing Yi and Ma Wan island. The total weight of concrete used in the two anchorages is about 300,000 tonnes.

3. Main cables – The cables were constructed by an aerial spinning process. The process involved drawing wires from a constant-tension supply, and pulling loops of these wires from one anchorage to the other, passing a 500-tonne cast-iron saddle on top of each bridge tower seating the cable. A total of 70,000 galvanised wires of 5.38 mm diameter were placed and adjusted to form the 1.1 m diameter main cable.

4. Suspended deck – The steelwork for the deck structure was fabricated in Britain and Japan. After delivery, they were further processed and assembled in Dongguan of China into standard deck modules. A total of 96 modules, each 18 m long and about 480 tonnes in weight, were prepared. These deck modules were brought to the site by specially designed barges and raised into the deck position by a pair of strand jack gantries that could manoeuvre along the main cable.

5. Approach span on Tsing Yi side – similar in form and cross-section to the suspended deck, but the approach span was supported on piers instead of cable-support. The first span was assembled on the ground and raised into position using strand jacks. Further erection then proceeded in cantilever in smaller sections, using derrick cranes stationed on the deck level. An expansion joint which allowed for a maximum thermal movement of 850 mm was also provided and located inside the approach span section.

The Tsing Ma Bridge was designed to carry two three-lane carriageways on the upper deck and two railway tracks on the lower deck. There are also two sheltered single-lane carriageways on the lower deck for maintenance access and as backup for traffic during typhoons when wind speed is still within acceptable limits. The construction cost of Tsing Ma bridge is $7.14 billion and the actual completion time was 57 months.

main contractor
Anglo Japanese Construction/Trafalgar House Construction (Asia) Ltd/
Constain Civil Engineering Ltd/Mitsui & Co Ltd  joint venture

 

Record-Breaking Island Link

 

The work base for Tsing Ma Bridge on Tsing Yi Island. This work base comprised concrete batching facilities, a steel handling and fabricating yard, material and equipment storage areas and sub-offices etc.

Partly completed bridge viewed from the main cable and looking towards Ma Wan. The tower of the Kap Shui Mun Bridge can be seen in the background

Partly completed bridge viewed from the main cable and looking towards Tsing Yi.

The Ma Wan Viaduct as seen from the Kap Shui Mun Bridge tower.

The work base for Ma Wan Viaduct on Ma Wan Island. The temporary linking bridge from Ma Wan to the island base of the Tsing Ma Bridge western tower can be seen in the centre of the photo.

Interchange at the Tsing Yi side. In the upper right corner is the expressway leading to the future Ting Kau Bridge which will link the Route 3 Country Park Section to Tsing Yi and Kwai Chung.

Close-up detail of the Interchange. The portal-braced bridge tower can be seen clearly here. The track of the Airport Railway is not visible in this photo as it runs in the lower deck section of Tsing Ma Bridge and, when arriving at the bank on Tsing Yi Island, heads underground.

The 250 m-long approach bridge supported on piers on the Tsing Yi bank, as viewed from the bridge tower.

The connecting section of the steel deck of the approach bridge linked to the coupling structure on the Tsing Yi bank. A derrick crane with a 200 tonne-capacity was positioned on the deck to assist with the lifting of the steel trusses.

Setting up of the derrick crane on the deck top of the approach bridge.

 

The Ma Wan Viaduct as seen from the Kap Shui Mun Bridge tower.
Joining of approach bridge to the Tsing Yi coupling structure.	Using SGB Alum form to construct the box section of the bridge coupling structure.
Detail of the complicated coupling structure which was built on top of the gravity anchor for the main cable. The three hollow sections inside the coupling structure comprise the connecting tunnel for the airport railway (centre) and the emergency carriage lanes (either side).	The main cable ascending from the cable chamber.
The main cable outside the cable chamber. The hexagonal object seen on the upper side of the cable is the hydraulic cable compacting clamp, the object on the lower side is the cable sorter. The 33,000 separate 5.38 mm galvanised steel wires are sub-divided into 80 strand groups before being tied onto the cable anchor.	Cable strands being tied onto the gravity anchor through adjustable tying bolts. The bolts are anchored to the gravity anchor which is made of mass concrete and weighs some 150,000 tonnes.
Close-up detail of the cable sorter.	A look at the finished cable chamber on the Tsing Yi bank.
External view of the cable chambers on the Ma Wan side.
The catwalk suspended on the main cable, as seen from the underside. The steel deck of the bridge was still not erected at this stage.	Detail of the 4m-wide catwalk used to access the main cable.
The cast iron cable stay which holds the two pairs of hanging cables for the bridge deck in position. The steel ribbon tapes, located at 1.5 m intervals, are temporary ties for the compacted steel wires that form the main cable.	The final sealing of the main cable. A strong epoxy resin-based paint is used to seal the surface of the cable which is then wrapped with a skin of galvanised iron wire. The rectangular-shaped device is the equipment used to carry out the wire wrapping.
The main cable passing through the saddle on top of the bridge tower.	Close-up of the saddle which holds the turning cable in position. The saddle is made of cast iron and weighs about 500 tonnes.

	.
	The Ma Wan Viaduct as seen from the Kap Shui Mun Bridge tower.
The work base for Ma Wan Viaduct on Ma Wan Island. The temporary linking bridge from Ma Wan to the island base of the Tsing Ma Bridge western tower can be seen in the centre of the photo.	Interchange at the Tsing Yi side. In the upper right corner is the expressway leading to the future Ting Kau Bridge which will link the Route 3 Country Park Section to Tsing Yi and Kwai Chung.
Close-up detail of the Interchange. The portal-braced bridge tower can be seen clearly here. The track of the Airport Railway is not visible in this photo as it runs in the lower deck section of Tsing Ma Bridge and, when arriving at the bank on Tsing Yi Island, heads underground.	The 250 m-long approach bridge supported on piers on the Tsing Yi bank, as viewed from the bridge tower.
The connecting section of the steel deck of the approach bridge linked to the coupling structure on the Tsing Yi bank. A derrick crane with a 200 tonne-capacity was positioned on the deck to assist with the lifting of the steel trusses.	Setting up of the derrick crane on the deck top of the approach bridge.
Joining of approach bridge to the Tsing Yi coupling structure.	Using SGB Alum form to construct the box section of the bridge coupling structure.
Detail of the complicated coupling structure which was built on top of the gravity anchor for the main cable. The three hollow sections inside the coupling structure comprise the connecting tunnel for the airport railway (centre) and the emergency carriage lanes (either side).	The main cable ascending from the cable chamber.
The main cable outside the cable chamber. The hexagonal object seen on the upper side of the cable is the hydraulic cable compacting clamp, the object on the lower side is the cable sorter. The 33,000 separate 5.38 mm galvanised steel wires are sub-divided into 80 strand groups before being tied onto the cable anchor.	Cable strands being tied onto the gravity anchor through adjustable tying bolts. The bolts are anchored to the gravity anchor which is made of mass concrete and weighs some 150,000 tonnes.
Close-up detail of the cable sorter.	A look at the finished cable chamber on the Tsing Yi bank.
External view of the cable chambers on the Ma Wan side.
The catwalk suspended on the main cable, as seen from the underside. The steel deck of the bridge was still not erected at this stage.	Detail of the 4m-wide catwalk used to access the main cable.
The cast iron cable stay which holds the two pairs of hanging cables for the bridge deck in position. The steel ribbon tapes, located at 1.5 m intervals, are temporary ties for the compacted steel wires that form the main cable.	The final sealing of the main cable. A strong epoxy resin-based paint is used to seal the surface of the cable which is then wrapped with a skin of galvanised iron wire. The rectangular-shaped device is the equipment used to carry out the wire wrapping.
The main cable passing through the saddle on top of the bridge tower.	Close-up of the saddle which holds the turning cable in position. The saddle is made of cast iron and weighs about 500 tonnes.

The hydraulic jack gantry for lifting the deck unit that works on the main cables.	Close-up look at the gantry showing the two hydraulic jack units on one side with the lifting strands.
Close-up look showing the mounting detail of the gantry. The gantry mounts and moves along the main cables by hydraulic clips. The cables in this case act as the rail for the gantry.	The lifting arrangement as viewed from the bridge tower. The barge with two typical deck units on it was pulled by tug-boats in order to align it into the right posiiton for the final lifting. Rows of hangers from the main cable for hanging the deck units are already in place.
Two typical deck units that weigh about 500 tonnes and measure 41 m x 18 m x 7.8 m; each were delivered to site from Dongguan by barge. The two pairs of lifting strands hanging down from the gantry were in position and ready for lifting.	The lifting arrangement as viewed from the Ma Wan side. The end section of the deck can be seen clearly here.
Positioning of the barge. Two pairs of attaching devices can be seen here on two ends of the deck for the coupling attachment of the lifting strands.	The lifting arrangement as seen from the underside of the partly aligned deck units.
The placing-in of a smaller deck unit that fills an odd gap between the standard decks. These kind of touching-up works are very common at the final stage of the erection.	A 500 mm deviation in level between two deck units before final alignment and adjustment is made.
The supporting detail of the deck to the portal frame of bridge tower. The decks in fact are not rigidly supported on the portal, the main cables supply the actual support. The set-up shows the jack blocks for adjusting the final alignment and level of the bridge deck.	Interior view of the Tsing Ma Bridge. The location as seen here is the airport railway coming out from the reinforced concrete connecting tunnel into the approach bridge on Tsing Yi side.
Workers prepare for the laying of the airport railway track in the deck interior.
The ties functioned also as the skylight of the airport railway as seen on the deck level. The opening provided by the skylight also acts as a pressure balance to minimise the wind effect during high wind.	The deck of the Tsing Ma bridge is pin-jointed to the reinforced concrete structure of the Ma Wan viaduct at one end and rests on a sliding joint which also acts as the expansion joint at the other end of Tsing Yi. This is one of the pin-joints located on the Ma Wan side.
The Bridge exterior with the stainless steel cladding cover on.	The external look of the bridge deck before the cladding cover is fixed.
Junction of two typical decks as seen from the underside of bridge. A mount-on sliding work platform can be seen here for doing the touch-up works on the bottom part of deck.	Close-up look at the sliding work platforms that are mounted on the bottom of the deck by rail.
The service access inside the approach bridge on Tsing Yi side. The engineering graded UPVC storm water drain can also be seen hanging on the underside of the deck.	Catwalk over the servicing corridor and the multi-decked cable tray. The inner face of the stainless steel cladding cover can also be seen on the right.
The cable tray that houses the control and power cables inside the servicing corridor on the sides of the deck interior.