review michael ch hui, doris yau major bridge development

REVIEW

Michael CH HUI, Doris YAU

Major bridge development in Hong Kong, China—past,present and future

© Higher Education Press and Springer-Verlag Berlin Heidelberg 2011

Abstract The first “modern” type of vehicular bridgewas built in Hong Kong China in the 1920s. The need foran efficient transportation system to cope with populationgrowth and enable economic development has demandedthe construction of more and more bridges since the middleof the 20th century. By 2007, Hong Kong had a total ofabout 1300 vehicular bridges. Four of these bridges,including the Tsing Ma Bridge, Kap Shui Mun Bridge,Ting Kau Bridge, and the cable-stayed bridge on the HongKong- Shenzhen Western Corridor, are considered to bemajor bridges supported by cables. Currently, the Stone-cutters Bridge on Route No. 8 is under construction and isexpected to be completed in late 2009. At the same time,the Hong Kong-Zhuhai-Macao Bridge will be in itsdetailed design stage soon. While efforts have been madeby bridge builders to construct these giant structures, theupkeeping of these valuable assets at a high standard andensuring their continuous functioning and performanceduring their intended lifespans will be another importanttask for bridge engineers. Wind and structural healthmonitoring system (WASHMS) will play a key role in thisrespect.

Keywords Tsing Ma Bridge, Kap Shui Mun Bridge, TingKau Bridge, Stonecutters Bridge, Hong Kong-Zhuhai-Macao Bridge, wind and structural health monitoringsystem (WASHMS)

1 Introduction

Looking back in history, Hong Kong, China began in themiddle of the 19th century as a fishing village where onecould hardly find any bridges on what Lord Palmerston

(the then British Foreign Secretary) had disparaginglydescribed as “a barren island, with hardly a house upon it”.Subsequently, Hong Kong started to develop into anindustrial and manufacturing center after the SecondWorldWar. Transportation networks were also developed to copewith ever-increasing economic and social activities. Moreand more bridges have since been built. To transform HongKong from an industrial city to an international financialcenter in the late 1990s, Hong Kong was in need of aworld-class international airport and an efficient transpor-tation network to connect the airport with the various partsof the city. A number of major cable supported bridgeswere built on the airport access routes as a result.Upon completion of the airport project, the focus of road

transport projects was transferred to cross boundarycrossings and the improvement of the local strategic roadnetwork. The Hong Kong-Shenzhen Western Corridor(HK-SWC) was completed 10 years after the territory’sreturn to the Mainland. Meanwhile, the StonecuttersBridge on Route No. 8 is currently under constructionand is expected to be completed in late 2009.Looking to the near future, the mega Hong Kong-

Zhuhai-Macao Bridge will soon enter its detailed designphase for target commencement in 2010. Experiencegained in constructing the earlier major bridges willdefinitely contribute to building this mega bridge.

2 Bridge building in Hong Kong

2.1 Early days

Hong Kong has a steep and hilly terrain. In the old days,most of its inhabitants could only cluster along thenorthern shore of Hong Kong Island and on the KowloonPeninsula. Throughout the 19th century, sea transport wasthe only means of transport in Hong Kong. All movementof goods within or outside the territory had to be done bysea as all warehouses lay along a 5 km stretch of theIsland’s northern shore. The first motor car was delivered

Received September 2, 2011; accepted September 28, 2011

Michael CH HUI (✉), Doris YAUS15/F, Civil Engineering and Development Building, 101, PrincessMargaret Road, Ho Man Tin, Kowloon, Hong Kong, ChinaE-mail: [email protected]

Front. Archit. Civ. Eng. China 2011, 5(4): 405–414DOI 10.1007/s11709-011-0136-4

to Hong Kong in 1915, but it was not until the 1920s thatsteps were taken to cater for motor vehicles specifically.This was the time when the first “modern” vehicular bridge(Kwong Fuk Bridge) in Tai Po was built (Fig. 1) [1]. Evenin the immediate post-Second-World-War years, HongKong had very few local industrial and economicactivities. Apart from railway, the most common types ofland transport at that time were rickshaws and sedan chairs.Bridges were usually built using primitive materials liketimber, stone, or cast iron.The situation changed in the 1960s when Hong Kong

experienced a sudden surge in population growth due tothe influx of immigrants from the Mainland. As industrydeveloped and population began to multiply, Hong Kongwas faced with the urgent task of providing homes andinfrastructures for its people. An ambitious program wasimplemented to provide new homes in the new towns ofthe New Territories for about 1.8 million people in mid1980s. One of the foremost items in this program was toprovide better transport connections among these newtowns. As a result, more and more bridges and viaductswere constructed as part of the program. With such a boomin the bridge construction industry and advances inconstruction technology and material science, bridgeswere usually designed as reinforced/prestressed concretestructures. Moreover, the precast segmental constructionmethod was introduced to Hong Kong in the 1980s forconstructing bridge viaducts over busy roads or above thesea near the shoreline.

2.2 Hong Kong’s new airport

China started to implement its open-door policy in the late1970s. As a result, industrial activities in Hong Kong weregradually shifted northwards to areas in the Pearl RiverDelta such as Dongguan. Hong Kong underwent a rapidtransition from an industrial and manufacturing center to a

service-based economy in the 1980s and then matured tobecome a financial center in the 1990s.From the 1980s to the late 1990s, Hong Kong was at its

golden age of bridge building during which a number ofworld class bridges were built. In the late 1980s/early1990s, Hong Kong decided to move its airport from thecity center of Kowloon to Chek Lap Kok on the LantauIsland. The new airport necessitated the construction of amajor new strategic highway of approximately 34 km inlength between the western part of Hong Kong Island andthe airport. This was the first physical connection betweenthe Kowloon Peninsula and Lantau. The key part of theconnection is the spectacular 4 km long Lantau Link,comprising the 1377 m span Tsing Ma suspension bridgeand the 430 m span Kap Shui Mun cable-stayed bridge.These two bridges carry both road and rail traffic.Shortly after the commissioning of the Airport Access

Links, the Route No. 3 (Country Park Section) wascommissioned in 1998 to connect traffic from the north-west New Territories to the Lantau Link. The 1177 m longTing Kau cable-stayed bridge forms part of this route. It isa unique and visually impressive structure, whichcontinues to attract world-wide and local interest.The Airport Core Programme was an extremely complex

and fast tracked program. To ensure successful implemen-tation of this ambitious program, Hong Kong looked forimported technology including different levels of expatri-ate personnel from experts down to construction super-visors and skilled laborers. As a result of the technologytransfer, Hong Kong has nurtured a number of experts inbridge construction and project management. The qualityand standard of the local construction industry have alsobeen improved significantly. The following major bridgeswere constructed during the golden age of bridge buildinghistory in Hong Kong.

2.2.1 Tsing Ma Bridge [2]

Tsing Ma Bridge has a main span of 1377 m and anoverall length of 2160 m (Fig. 2). Obviously, a bridge ofthis span length would be extremely flexible and windsensitive. The following discussions will focus on thisaspect. As the Tsing Ma Bridge will be the only road/raillink to the airport, it is essential that this access bemaintained in all but the most severe weather conditions.This “all-weather” capability is achieved by locating thetwo railway tracks and two protected roadways in thelower deck, where they will be protected by stainless steelcladding. The final design uses a double-deck steel boxconstruction with truss stiffening and non-structural edgefairings (Fig. 3).Learning from the experience of the Tacoma Narrows

Bridge collapse in 1940, the deck of the Tsing Ma Bridgewas streamlined. Extensive wind tunnel tests confirmedthat the adoption of a streamlined deck section with faired

Fig. 1 Kwong Fuk Bridge in Tai Po

406 Front. Archit. Civ. Eng. China 2011, 5(4): 405–414

edges and central air vent would ensure aerodynamicstability in an extreme wind speed of 95 m/s (one-minutemean). In addition, investigations were undertaken toensure that the air flow within the lower deck would be atlow speeds, as required for highway and railway operation.It has been established by wind tunnel measurements thatthe wind speed in the sheltered deck will be approximately40% of the external wind speed. Graduated wind shieldsare provided on the upper deck adjacent to the bridgetowers.

2.2.2 Kap Shui Mun Bridge [2]

The Kap Shui Mun Bridge has a main span of 430 m andan overall length of 750 m (Fig. 4). Like the Tsing MaBridge, it carries a six-lane highway on the upper deck andtwin railway tracks plus two sheltered road lanes on thelower. It is supported by two planes of stay cables. Thebridge is a record-breaker in its own right, but is oftenovershadowed by its giant neighbor on the same link.There are a number of unique features on this bridge. It

is one of the stiffest structures ever to be incrementallylaunched, and has perhaps the most heavily-loaded cablestay towers ever built. The middle 387 m of the 430 mcentral span is a steel/concrete double-composite boxsection (Fig. 5). The upper and lower concrete decks arecast onto the prefabricated steel webs at the Lantau sideof the site, before being floated out and hoisted intoposition. The side span and the transition elements of thecentral span are of post-tensioned in situ concrete. Thetransition elements are jacked into position, through themiddle of the towers, by the incremental launchingmethod. This method was used for the first 45 m of thecentral span coming out from each of the towers, i.e. up toa defining point where water in the Kap Shui Mun Channelwould be deep enough to allow the composite units to befloated out.

Fig. 2 Elevation of the Tsing Ma Bridge

Fig. 3 Hybrid arrangement of stiffening truss and box of theTsing Ma Bridge

Fig. 4 Elevation of the Kap Shui Mun Bridge

Michael CH HUI et al. Major bridge development in Hong Kong, China—past, present and future 407

2.2.3 Ting Kau Bridge

The Ting Kau Bridge has an overall length of 1177 mwith two cable-stayed spans measuring 475 and 448 m(Fig. 6). One of the outstanding features of this “landmarkbridge” is the three towers, with heights of 172, 200, and163 m above the Hong Kong Principal Datum, located onthe Ting Kau Headland, on the reclaimed land, and on thenorth-west Tsing Yi shoreline, respectively. In addition totransverse stabilization cables, the 200 m tall central tower

is stabilized by a pair of longitudinal stay cablesconnecting the tower head to the deck sections adjacentto the side towers. According to the bridge designer, thespecial design of the bridge towers was somewhatanalogous to “working and appearing like masts ofsailboats”. They may make the road users feel like“entering a ship crossing the Rambler Channel and thenleaving it again.”The two separated bridge decks supported by four

planes of cables on both sides of the three towerscontribute to the slender appearance of the bridge, andare considered to be aerodynamically favorable. Owing toa short design and construction period, a compositestructure was adopted for the deck design. The steel/concrete deck comprises a steel grid of two main outergirders with steel cross girders spanning 18.77 m at4.5 m spacing and a concrete slab on top formed by4.4 m � 4.6 m precast panels of 230 mm thick and cast insitu joints (Fig. 7).

2.3 Post-1997

In 2001, with increasing economic and social activities

Fig. 5 Steel/concrete double-composite box section of the KapShui Mun Bridge

Fig. 6 Elevation of the Ting Kau Bridge

Fig. 7 Erection of the deck of Ting Kau Bridge


between Hong Kong and the Mainland, the three existingHong Kong-Shenzhen vehicular border crossings becamenearly saturated. The governments on both sides recog-nized the need to construct the fourth crossing to alleviatethe traffic congestion at the existing border crossings and tofacilitate the flow of people and cargo between the twoplaces. It was decided to place the fourth crossing to linkup the North-west New Territories with Shekou ofShenzhen across the Deep Bay, i.e. the Shenzhen WesternCorridor (HK-SWC).Deep Bay has a high ecological value because of its

extensive low-lying inter-tidal mudflats and mangroveforests. The alignment of the corridor was chosen carefullythrough the cooperation of governments on both sides ofthe border. The Hong Kong section of the HK-SWCincludes the construction of a cable-stayed bridge with a159 m tall single concrete inclined tower and a 210 m longsteel main span supported by a single plane of cables(Fig. 8). The deck is a single steel box girder 38 m wideand 4 m deep (Fig. 9).

3 Present

The design and construction of the 1018 m span Stone-cutters Bridge represent the present situation of majorbridge development in Hong Kong. The bridge is a keyelement on Route No. 8 leading to the airport in HongKong. The route is being built to relieve traffic congestionon the existing airport access Route No. 3 and is expectedto be completed in late 2009.Hong Kong presents a unique maritime setting that

makes it one of the world’s remarkable places. TheStonecutters Bridge will be a major landmark in thewestern area of the harbor and will be visible from manyparts of Hong Kong. Hence, the Highways Departmentwas determined to deliver this mega bridge project at thehighest aesthetic standards and raise it to an iconic statuswith symbolic value. The following is a brief account ofwhat have been done with a view to achieving this goal.

3.1 International design competition

For the first time in Hong Kong, the conceptual design ofthe bridge was obtained through the conduct of an openinternational design competition. The main objective of thecompetition was to secure a reference scheme that wouldmake the Stonecutters Bridge stand out among the world’slong span bridges and become a fitting landmark of theharbor and a gateway for the container terminal, therebyunderlining and promoting the image of Hong Kong as avibrant and important center of international trade.The competition was conducted in two stages, with

27 entries in Stage 1 which were whittled down to 5 inStage 2. The entries were assessed by two committees, i.e.the Technical Evaluation Committee and AestheticEvaluation Committee, each of which comprised interna-tional and local experts as judges. The winning design wasa cable-stayed bridge with two mono-column pylons each

Fig. 8 Elevation of the Shenzhen Western Corridor Bridge

Fig. 9 Erection of the 38 m wide and 4 m deep steel box girder


298 m high and an aerodynamic twin deck. The total lengthof the bridge is 1596 m with a main span of 1018 m. It hasfour back spans having lengths of 79.75, 70, 70 and 69.25m at each side of the main span, respectively. The towersare in concrete up to level+ 175 m and in steel-concretecomposite from level+ 175 m to level+ 293 m with theouter skin being stainless steel. The top 5 m are a glasscovered steel structure, which acts as an architecturallighting feature and provides storage space for main-tenance equipment. The bridge deck at the central span andin the vicinity of towers will be of steel while the side spanswill be of concrete. The twin longitudinal deck girders are14.3 m apart and are connected by cross girders at 18 mand 10 m intervals in the central span and side spans,respectively. The two planes of stay cables take a modifiedfan arrangement, anchored at the outer edges of the deckalso at 18 m spacing in the central span and 10 m spacing inthe back spans. Please refer Figs. 10 and 11 for the generalarrangement of the bridge.

3.2 Aerodynamic considerations

For a twin deck structure like the Stonecutters Bridge,vortex shedding actions may be amplified as the shedvortices drift across the central air gap and impinge on thedownwind girder. One effective way to mitigate vortexinduced oscillation is to provide guide vanes at the flowseparation point (at the knuckle line) of the soffit in order toguide the air flowing underneath the deck to prevent ordiminish rhythmic vortices formed at the upwind knuckleline of the windward deck [3]. This method hassuccessfully been adopted in mitigating the vortex inducedoscillation of the Storebaelt Bridge. Figure 12 illustratesthe concept. Like many other projects, the study of vortexshedding vibration of the Stonecutters Bridge deckemployed sectional models of a scale of 1∶80. The testresults indicated that the guide vanes had not been effectivein mitigating vortex shedding vibration. It was thought thatwith the low Reynolds no. (Re) employed in the 1∶80 scale

Fig. 10 Elevation of the Stonecutters Bridge

Fig. 11 Steel deck section of the Stonecutters Bridge


wind tunnel test, the boundary layer growing along thesoffit plate becomes rather thick, thus limiting a high flowrate through the vanes, making the vanes ineffective [4].Hence, it was decided to pioneer some high Re tests inorder to further investigate the effectiveness of the guidevanes. Sectional model tests using a bigger scale of 1∶20were then carried out in a bigger wind tunnel with higherwind speeds with a view to raising Re by one order ofmagnitude. The guide vanes design which had failed in the1∶80 scale tests proved to be very efficient in the 1∶20 scaletests. The vortex shedding vibration response wascompletely eliminated. A number of interesting findingswere also revealed in determining the steady-state aero-dynamic force coefficients under different Re [5].

3.3 Durability considerations [6]

While great efforts have been made to obtain a highstandard and quality design through the conduct of aninternational design competition, it is equally important toensure that the bridge will be durable and that the specialfeatures built into the design can be long lasting withminimum maintenance effort. The conduct of a properdurability assessment of the design will provide thenecessary framework for achieving that goal. Some specialmeasures have been adopted in the Stonecutters Bridgeproject from a durability point of view, such as:1) The use of micro-silica to make the concrete of lower

tower less permeable, coupled with the use of Grade 304

stainless steel reinforcement for the outermost layer andthe ties.2) The use of duplex grade stainless steel for the steel/

concrete composite upper tower structure.3) The use of a dehumidification system for the inside of

steel deck to avoid the use of a sophisticated paintingsystem, which would be costly to apply and maintain.

3.4 Maintenance considerations [6]

3.4.1 Maintenance access

It is a basic principle in the design that all important partsof the structure should be accessible. Access facilitiestherefore are designed to meet this principle. Access to allimportant parts of the structure must be achieved withoutany disruption to traffic, which given the strategic nature ofthe Stonecutters Bridge as a major route to the Hong Kongairport and container terminals, is a major consideration.Apart from the routine maintenance access provided in theearlier major bridges such as the rack and pinion lift formaintenance inside the bridge towers and the underslunggantries for maintenance outside the steel deck and stayanchorages, the Stonecutters Bridge will also be equippedwith a shuttle train running along the entire length of thedeck for personnel and equipment (Fig. 13). The exteriorof the towers above deck level is accessible from a cradlesuspended by a permanent derrick on the tower top.

3.4.2 Wind and structural health monitoring system(WASHMS)

Bridge health monitoring serves an important role inpredicting the structural behavior of long span bridges andhelping bridge owners to maintain their valuable assets.The Highways Department has ten years of experience inoperating a sophisticated wind and structural healthmonitoring system for long span cable-supported bridges.WASHMS was first installed on the Tsing Ma Bridge, theKap Shui Mun Bridge and the Ting Kau Bridge in 1997.

Fig. 12 Anticipated flow pattern without and with guide vanes

Fig. 13 Shuttle train inside the southern girder of the Stonecutters Bridge


With the experience gained in operating this system for afew years, the second generation was evolved and put intopractice on the cable-stayed bridge in HK-SWC. Again,with the experience gained in implementing the HK-SWCWASHMS, the Highways Department has designed thethird generation WASHMS, which is being installed on theStonecutters Bridge (Fig. 14). The third generation systemaddresses the problem encountered in the earlier systemswhere data retrieval from storage for processing andanalysis was inefficient. The system also enhances thecorrelation and regression analyses to be carried out indifferent views varying from two-dimensional to multi-dimensional views thus making the structural healthmonitoring system more user-friendly [7].

3.5 Summary

The planning, design and construction of the StonecuttersBridge posed many challenges to bridge engineers. Thehigh quality expectations in a landmark structure justifiesthe conduct of an international design competition toobtain an elegant design. After that is achieved, the nextimportant mission is to ensure that such a design will bebuildable, durable, easy to maintain, and safe to operate.Much effort has been spent in various stages of the projectto achieve these goals. With its construction commenced inApril 2004, the Stonecutters Bridge is now at the mostcritical stage of its life where all the planned and designedmeasures will be implemented to ensure the health of thebridge when it is born in 2009.

4 Future

The implementation of the new airport and its access route10 years ago is a milestone in Hong Kong’s major bridgeconstruction history. At the same time, the transportationnetwork of Hong Kong started to take shape. Thecompletion of HK-SWC in 2007 and the full commission-ing of Route No. 8 including the Stonecutters Bridgeby end of this year will refine the network. To furtherenhance Hong Kong as a transportation hub, there are anumber of mega scale road and railway routes beingplanned for completion by the middle of the next decade.The majority of these projects, however, are tunnels. Asfar as bridges are concerned, the focus will be placed onthe Hong Kong-Zhuhai-Macao (HKZM) Bridge and itslink road to the existing transportation network. TheHKZM Bridge comprises a proposed series of bridgesand tunnels that would connect the west side of HongKong with Macao and the neighboring city of Zhuhaiwhich is situated on the west side of the Pearl River Delta(Fig. 15). The proposed 29 km bridge is comparablewith the world’s longest bridge, the Second LakePontchartrain Causeway in the United States, which is38.4 km long. Construction is expected to commence inlate 2009 but no later than 2010. The bridge will becompleted around 2016.Looking to the farther future, we have devised

preliminary conceptual plans to build more strategic routesto link up Lantau Island with the West New Territories.These preliminary plans may opt for long span bridge

Fig. 14 Wind and structural health monitoring system of the Stonecutters Bridge


solutions. However, it might be too early at this stage toeven make a prediction on what will happen.To ensure that Hong Kong will continue to enjoy a

sustainable development in the years to come, oneimportant aspect is to upkeep our valuable assets to ahigh standard. WASHMS will play a key role in thisexercise. WASHMS in Hong Kong was born ten years ago.The systems as well as their master bridges therefore arestill at their young ages. Up to this point, major structuraldefects still have not been observed. We will take thisopportunity to plan and schedule the work of WASHMSsuch that we could prepare ourselves for the near futurebefore our valuable stock of elegant bridges gets older andsuffers from health problems. While they are young andstrong, we can carry out investigation work on thestructural performance of the bridges and set up computerbridge models to predict/evaluate the bridge responsesduring in-service (mainly for fatigue assessment) andextreme events (mainly for stability and damage assess-ments). Such investigation and development work willprovide valuable information and solutions to the bridgeoperators as the bridges get “older and weaker”. As timegoes by, the number of damaged or deteriorated compo-nents in old bridges due to degradation will increase.The understanding of the deterioration process will notonly improve the efficiency of the corrective/preventivemaintenance, but also provide solutions for predictive/

condition-based maintenance. There are therefore still a lotof potential for further research and development inWASHMS.

5 Conclusions

Bridge construction is critical to the development ofHong Kong and its economy. Bridges narrow the gapsbetween one region and another throughout theterritory. Bridges speed up cross-region and cross-bordermovement of people and goods and improve the overallefficiency of the transport system. During the past years,bridges were built because of better economic conditionsand more bridges also bring about better economy to HongKong.The bridge construction techniques in Hong Kong

became mature with the completion of several large-scalebridges over the years. Like many other developedcountries, the focus of bridge engineering will unavoidablybe shifted to the maintenance and operation of thecompleted bridges. WASHMS plays a key role in thisrespect.

Acknowledgments The authors wish to express their gratitude to theDirector of Highways of HKSAR, C S Wai, for his permission to publish thispaper. Views expressed in the paper are entirely those of the authors.

Fig. 15 The Hong Kong-Zhuhai-Macao Bridge


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Michael CH Hui, received his B.Sc (Eng)from the University of Hong Kong, M.Sc.(Bridge Engineering) from the University ofSurrey and Ph.D. from the Tongji Univer-sity. He is now the Chief Engineer ofHighways Department in HKSAR.

Doris Yau, received her B.Sc. (Eng) from theUniversity of Hong Kong, M.Sc. from theHong Kong University of Science andTechnology. She is now the Engineer ofHighways Department in HKSAR.


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