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The Cross Bay link (CBL) bridge is a 1 km sea crossing that forms the centrepiece of the new east–west express highway link in Hong Kong. This £250 million project features an iconic 200 m span butterfly double-arch bridge and a series of concrete box girder spans supported on specially sculpted V-piers and large piled foundations. This paper describes the innovative construction methods adopted for building the bridge safely and efficiently in an extremely challenging marine environment, a process that relied on the extensive use of design for manufacture and assembly solutions, with most of the bridge elements above the sea level being prefabricated or precast off site. This includes the construction of the 10 000 t steel arch bridge, which was fully prefabricated near Shanghai, then transported to Hong Kong by a semi-submersible barge, and eventually erected onto the piers using the float-over method. In addition, most of the concrete decks, piers and the pile cap shells were precast off site and then lifted into position on site. This project holds a number of engineering records in Hong Kong, including the longest arch bridge, the first-time adoption of S690QL high-strength steel for major bridge elements and the largest scale implementation of the float-over erection method. [ABSTRACT FROM AUTHOR]

Varying temperatures significantly affect long-span cable-stayed bridges. However, quantitative studies on their temperature behaviors are limited. Existing studies focus on 2D or 3D models of bridge segments only, exclude cables from heat-transfer analysis, and utilize inaccurate environmental conditions. For the first time, this study comprehensively and accurately investigates the global 3D temperature distribution of long-span cable-stayed bridges by integrating the heat-transfer analysis and field monitoring data. A navigation channel bridge of the Hong Kong‒Zhuhai‒Macao Bridge is used as the testbed. A global 3D refined finite element model of the entire bridge is established. The external thermal boundary conditions of the outer surfaces of the structure are carefully determined based on the real-time ambient temperature, wind, and solar radiation, which are tailored for each surface to reflect the influence of the geometric configuration. The internal thermal boundary conditions of the inner surfaces of the box girder and tower are dependent on the measured ambient temperature, considering the vertical temperature difference of the girder and the uniform temperature inside the tower. Then, the numerical heat-transfer analysis and field monitoring data are integrated to calculate the detailed temperature distribution of the entire bridge in different seasons. Results show that ambient temperature, wind, and solar radiation significantly affect the temperature distribution. For the girder, the vertical temperature difference is significant throughout the year, and the transverse temperature difference is nonnegligible in winter and summer, while the longitudinal temperature difference is trivial. The internal temperature of the tower remains stable owing to the insulation of the concrete. The temperatures of the cables vary from each other, which may cause stress redistribution within the structure. The calculated temperatures are in good agreement with their measured counterparts. The temperature results will be used to calculate the thermal-induced responses in the companion paper in a unified manner. [ABSTRACT FROM AUTHOR]