The Tsing Ma Bridge is the main passage to connect the downtown of Hong Kong with Hongkong International Airport. It is a double-decked bridge, connecting Tsing Yi Island and Ma Wan Island, with a main span of 1377m, rendering itself the longest suspension bridge of highway and railway in the world.          Designed life for the said bridge is identical to the practice in England—120 years. Early in development of the works, designers were aware of the strategic importance of this maritime engineering as the sole channel to the Lantau Island. To uninterrupted operation, the bridge must meet 3 requirements. Firstly, the bridge must ensure traffic operation under extreme weather conditions. To satisfy this purpose the Tsing Ma Bridge and the Kap Shui Mun Bridge are adopting double-deck with sheltered on the lower deck carriageway. Secondly, the bridge shall be free from impact damage arising from any large ship's collision, which can be effectively achieved from position of all piers on shore. At last, owing to the high-speed of typhoon experienced in Hong Kong, it is vital to acquire aerodynamic stability.          As the sole passage to the International Airport, the said bridge is required to perform well in any weather conditions to maintain connections with any district of Hong Kong. As a result, the Bridge is designed to be double-decked. In normal condition, the upper deck is for all kinds of vehicles. In the case of strong wind, namely when the wind averages 40—65km/h (or the gust of wind reaches 60km/h), the middle carriageway will be closed to prevent any danger, with only two lanes operatable in each direction. Meanwhile, high cargo trucks, guided to travel on the lower deck, will not be admitted onto the upper deck. In the case of wind increasing to 65—95km/h, or when a gust of wind reaches 120km/h, the upper deck will be completely closed, with all autos to pass on the lower deck. If the wind runs at 220km/h, the whole bridge will be closed. Except for emergency engineering autos, there will be no admission for autos. Of course, at the same moment, the airport will have been closed too. In wind tunnel test concerning closed box girder, wind speed in the inner box, namely in the lower deck, is about 40% of the speed outside the bridge, thus the above-mentioned practice is based upon experimental data.          To prevent the suspension bridge from collision from large ships, the eastern pier is constructed on the seashore of the Tsing Yi Island, with further safety from protection embankment. The western pier foundation is of pre-fabricated reinforced concrete caisson 16m high positioned on a pre-treated seabed about 10m deep, with protection embankment and breakwater, to form an artificial island. Such a design can avoid any potential collision from large ships, and can shorten the length of the main span and construction duration thus to reduce construction cost. The main span is determined by the width of the navigation channel underneath, where it is 1200m wide. As the eastern pier is located on the seashore and the western pier in shallow water, the most economical span is set at 1377m, with 62m as navigation clearance.          In the site of the Tsing Ma Bridge, a gust of three seconds long that occurs in every 200 years runs at 83m/s, namely at 300km/h, so there are two problems to solve in the structural design. One is that the bridge structure should be designed in such shape as to reduce wind force on it and strong enough to stand in the wind. Therefore a suitable structural section should be achieved. Another problem is that in the case of typhoon the bridge shall maintain dynamic stability and prevent shutter or loss of balance.          Experience has proved that the installation of aerodynamic stabilizers on the both sides of traditional box girder bridge will behave like plane wings to greatly reduce traction force. Traditional suspension bridges can resist wind that runs at no more than 50m/s. In Europe, after reform a streamlined box girder, bridge has proved to improve stability to resist wind up to 55m/s. However, the designed wind speed for the Tsing Ma Bridge runs much faster, which therefore requires the design of a new shape of the bridge. Experience from truss bridges indicates that air gap in the bridge structure, which is convenient for passage of air, will add stability to the bridge and also reduce resistance to wind of critical unstable shutter. Because of these factors the Tsing Ma Bridge is designed to be of streamlined closed box type, identical to those suspension bridges in Europe, with additional air gaps in the bridge structure for air to pass through, with stainless steel lining on the wing points to reduce wind resistance. Wind tunnel test showed that critical flutter speed in the bridge overtakes the designed 95m/s from an attack of strong breeze. In the case of low wind there is limited vortex excited oscillation, to produce no impact upon autos and trains. Meanwhile, there is no need for aerodynamic stabilizer, to reduce consumption of steel materials. This design was recommended and introduced in the International Bridge Dynamics Conference in 1981, to earn much appreciation from foreign experts.          In working load, concrete is the most ideal building materials. In recent years use of slip form for high building construction has proved to greatly reduce construction duration, which is thus adopted in construction of the towers of the Tsing Ma Bridge, to complete each tower in 3 months with construction of 46000m 3 of concrete.          Within the two tower columns elevators are erected, at the top of which there are seats and lights, convenient for serviceman to sit and to control the movement of the elevators to observe the concrete condition within the tower. Within the column there are galvanized steel staircases and platforms for maintenance and for use in case of elevator breakdown.          Cables for the suspension bridge were erected in normal way. The main cable is composed of 80 strands (each strand contains 368 pieces of dia. 5.38mm steel wire). After wiring strand cable measures a dia. 1.1m, to consuming steel wires totaling 28,000 tons, lasting 160,000km in total length, almost four times in the Earth.          The external shape is in line with aerodynamic stability. In structure the bridge is of biaxial truss structure, namely longitudinally it is of traditional truss type while transversely of vierendeel truss, with the steel plates on upper and lower deck serving as flanges. The two longitudinal deck of the same height as the bridge are at a distance of 26m, to form composite girder with the longitudinal bridge. The transverse girder is of three vierendeel trusses, hung over the cables. The cables are of 18m in transverse distance, thus the center distance between the main transverse girders is 18m too. There are 3 secondary cross beams between the main cross beams, namely the center distance between the secondary beams lasts 4.5m. Along the two sides of the streamlined bridge there are stainless steel covers, to control the air traveling through the bridge. In the bridge body there are air gaps, which is convenient for air passage and adds to bridge stability and also to critical shutter speed. From outside the bridge looks likes streamline box girder, while inside it is of traditional truss. In the bridge there are 3 chambers, with the central one available for airport express train, while the other two for emergency and maintenance purpose.          The steel structure of the bridge totals 50,000tons, with England and Japan each to manufacture half of the bridge components. The manufactured components were then shipped to Shatian Town, Dongguan of Guangdong Province to be processed, assembled and painted in a plant of 600,000 m 2 . After assembly one section is 36m long and 41m wide, which weighs 1000 tons and was shipped to the site on special towboats, traveling for about 10 hours to the site, to be lifted to the final position with the erection facilities on the cable. To lift one-thousand-ton components into position is far from easy, maybe a record in the world.          Change in temperature and various additional loads may produce angle displacement at the bridge end, which eventually causes the expansion system at the bridge end to displace vertically or horizontally or angle rotation. Poor design of the said expansion system would produce negative impact which might endanger running vehicles or derail trains. To reduce the degree of angle displacement, there is corresponding arrangement in the Tsing Ma Bridge. From horizontal view, there are horizontal restrained supports at the bridge ends, at the towers location and at the top of the side span. Such a design is capable of not only sharing horizontal stress, but also reducing girder end horizontal angle displacement and avoidance of horizontal displacement, to result in minimum horizontal angle displacement in the expansion system. In front view, there is a hinged end at the anchor point at Ma Wan to bear all the longitudinal stress. Longitudinal the bridge is of continuous girder, so there are movable bearings at all the top of the columns and at the two towers location, in order not to bear horizontal stress, thus the bridge will be free to extend toward the anchor point on Tsing Yi Island, which will bear all the horizontal movement (≦700mm). To reduce bridge's horizontal angle motion, there are struts in the side span, with the bridge rigidity strengthened to meet the need for railway design, due to the requirement that the horizontal and vertical angle displacement at the rail expansion joint shall fall within 0.33 0 or max at 0.10 0 , which is sufficient to ensure safety for train movement so that passengers will still feel comfortable when the train runs at 135km/h passing the expansion joint.          The expansion joint is designed to be of traditional roller bearing, with products of Mageba brand from Swiss, like a accordion. The said Swiss product has been used in many large-scale suspension bridges in the world, which reduces much maintenance.          The Tsing Ma Bridge is under the management of a special unit, named the Tsing Yi island to the Lantau Island Trunk Line Engineering Management Section (I once served as director for many years), composed of engineers experienced in bridge engineering from the Highways Department . The said section is mainly responsible for the plan and construction of the three bridges, namely the Tsing Ma Bridge, the Kap Shui Mun Bridge and the Ting Kau Bridge.          During the design of the Tsing Ma Bridge, there was almost no engineers experienced in design and construction of suspension bridges in Highways Department, which invited consultant engineers to cooperate in design of the bridge. The chief engineer and the consultant engineer from the Highways Department cooperated to workout the design standard and specifications, followed by drafting detailed design and contract. In construction of the bridge, the Highways Department dispatched relevant engineers to work with consultant engineers at site, for supervision of the bridge construction, in order that engineers from the Highways Department could acquire experience to be competent in construction of suspension bridges. Later in construction of Ting Kau Bridge Highways Department was staffed with experienced engineers sufficient and competent to supervise construction of Ting Kau Bridge with no need to employ consultant engineers.          The Hongkong's traditional contract for civil engineering is based upon the blueprints drafted by British Civil Engineering Association, with some minor modifications to adapt to situations in Hong Kong. To prevent the construction lost from potentially going beyond the budget and to guarantee the completion of the project within specified date, special clauses are added to the contract, together with some modifications of existing terms and clauses so that the Client (Highways Department) could effectively control the engineering cost and encourage the contractors to construct the bridge in line with the work procedures.          Here some special clauses are introduced.          Common contract stipulates that construction cost will be paid to contractors, usually on monthly basis based on the work done after measurement. For example, in the case of completion of 100m 3 of earth work, the payment will be 100 timed by the contracted unit price as entered against 1 m3 of earthwork in the contract. But the bridge contract makes payment in accordance with the fixed progress chart in the contract which gives a progress chart for each item of works, such as the foundation, the tower, the bridge, and the anchorage. For example, the foundation must be completed in 12 months after commencement date, which means the first month shall see completion of 5% of the work, the second month of 12%, and the third month 20%…while the contractors may, at the tender stage on the basis of its own program, construction method and equipment resources, make any or no revision of the progress charts as specified by the Client. But signature makes the contract legal documents to be observed by both parties. After commencement, in the case of the contractor's timely completion of 5% of foundation, he will be paid accordingly, namely 5% of the total foundation construction cost. But if the contractor completes only 4% of the said works within the described duration, he will be paid not a penny, as he fails to meet the progress chart requirement. If he completes 6% of the said works, he will still be paid 5% of the contracted construction cost. In this way the contractor will make greatest effort to perform works in line with the progress chart, in order to get timely payment and profit, while the Client can make corresponding financial arrangement and payment schedule, with no need for temporary financing. This makes the Client well prepared for control of finance because he may apply for loan from banks.          Other special articles include the stipulation that the contract is of fixed price lump sum contract, namely the contracted price will not be subject to any adjustment in the case of prices fluctuation. The signature of the contract will mean the total price will never be modified so the contract price at the time of commencement remains unchanged until the completion of the works. In other words, the quoted prices as entered by the contractor shall be considered to include any price rise of building materials and manpower due to inflation that occurs in the construction duration. Consequently, the contractors can place order on required materials in the form of forward contract(s) with foreign manufactures and suppliers, to reduce any risk arising from price fluctuation. The contract also stipulates that the works will not be subject to time extension because of interference from typhoon or rain. The contract also offers a chance to employ manpower from outside Hong Kong in order to minimize any problem arising from shortage of laborers in site works in Hong Kong. Such fixed price lump sum contract proves successful in construction of subway and some large buildings as developed by private-owned companies in Hong Kong. Such an arrangement is expected to ensure the construction cost to fall within the estimated budget and to ensure the works to be completed as scheduled.          Other articles in the contract are basically identical to those in standard contract conditions. For example, the contractor(s) must submit a Contractor's Performance Certificate valuing 10% of the contract price. In the case of poor performance during construction with poor and unsatisfactory progress, the Client may withdraw the contract and then re-tender to award another contractor to complete the remaining works, with the contractor's performance certificate confiscated and encashed by the Client. The Tsing Ma Bridge being as the sole way to the International Airport, failure to complete it would create great loss and huge negative social effect, thus the contract offers heavy penalty for each item of works for failing in line with the progress chart. Failure to observe the designed completion date will invite fine—the fine for each day of delay will be 1,350,000 Hong Kong Dollars; if the delay goes more than 30 days, fine for each day will be as high as 3,450,000 Hong Kong Dollars, with maximum fine at 900 million Hong Kong Dollars.          A lot of works of the Tsing Ma Bridge will be carried out high above the ground or underground, much more difficult than common civil engineering works, thus in need of special attention to construction safety. The contract stipulates that there shall be one safety engineer responsible for construction safety for every 200 workers so that the contractor shall make scheduled lectures to its workers on safety operation by way of small-sized safety discussions and training. The chief resident engineer shall dispatch a senior engineer under him solely responsible for check and supervision of site safety and hold monthly meeting discussing site safety and prepare reports concerning safety situations. The Client shall pay bonus in the case of sound safety record every month. While in the case of poor performance with many accidents in the site, the contractor shall suffer punishment or even be forbidden from bidding for other government projects in Hong Kong.          For the sake of quality guarantee for the Tsing Ma Bridge, the contractors are required to include a complete list of “QC Plan” in its tender to promote complete QC and quality supervision. The said Plan must be composed in line with ISO 9001 standards into 3 parts, namely a) engineering quality pamphlet; b) quality check and plans; c) quality check procedure. The exact content of such planning shall accommodate different processes and various situations in the course of design, procurement of materials and construction. The plan shall state that each step will be reviewed or checked by independent person to effectively implement QC.          At the end of 1990 the Client sent invitations to world-famous consortiums and manufacturers, expecting them, in the case of their interest in construction of the Tsing Ma Bridge, to submit their job-related experience, company financial report and resources, and received from 11 consortiums. After review 5 consortiums were considered to have passed pre-qualifications. On July 31, 1991, the Client delivered to them tender and relevant documents, inviting them to bid for the Tsing Ma Bridge.          Unfortunately, one consortium and its partner withdrew from bidding so there were only 4 consortiums in tender. The submission date was set on December 16, 1991. the contract was awarded in May 1992 at cost of 7.10 billion Hong Kong Dollars with construction period of 5 years or 60 months. The Bridge was completed by May 1997 within the specified time. The beautiful Tsing Ma Bridge has become a noticeable scene in Hong Kong to be compared to the Golden Gate Bridge in San Francisco.