According to the Tianjin Municipal Transport Commission, the 2016—2017 China Construction Engineering “Luban Prize” has been officially announced, and the Jishan Expressway Haihe River Bridge project in Tianjin has been honored with the award. The bridge adopted six new technologies with independent intellectual property rights, overcoming multiple technical challenges and accumulating valuable experience for the construction of similar bridge projects.
Chang Runhao, deputy director of the Construction Management Division of the Tianjin Municipal Transport Commission, introduced that the Jishan Expressway Haihe River Bridge project has a total length of 4,024 meters, crossing over the Haihe River, Haigu Road and Tianjin Avenue in sequence. The section over the Haihe River adopts 70+110+70-meter variable cross-section continuous steel box girders, while the rest adopts steel-concrete composite girders and prestressed cast-in-place concrete continuous box girders. The bridge deck is divided into two parallel carriageways, each 17.8 meters wide, with eight lanes in both directions, a building area of 143,000 square meters, and a total investment of 730 million yuan.
“The application of multiple independent innovation technologies, the environmental protection concept of green transportation, and the quality control standards of striving for excellence in creating a quality project are the keys to the project winning the award,” said Wang Fushan, director of the Tianjin Municipal Transport Commission. The bridge has a novel structural design and a unique shape, adopting a “V”-shaped main pier design. At the same time, the bridge is also the key node project on the entire Jishan Expressway with the most construction technical difficulties, the largest scale and the most complex environment.
Sun Lixin, general manager of China Construction Sixth Engineering Bureau, introduced that during the construction of the in-water “V”-shaped pier, the most difficult part of the project, a parallelogram in-water cofferdam foundation pit 63.4 meters long, 16.8 meters wide and 13.5 meters deep was built, overcoming the construction difficulty of deep foundation pit support for large-volume special-shaped in-water cofferdams, enabling the successful completion of bottom-sealing concrete pouring and thus ensuring the quality of the cofferdam base. This new process and new technology also obtained a national invention patent.
In addition, the installation of the steel box girders also brought new challenges to the project builders. The superstructure of the project adopts a circular curve steel box girder structure. Because the bridge is located in a flat curve skew section, each component of the steel box girder is a special-shaped component, with none similar to another. The cumulative length of on-site welds reached 19,000 linear meters, and all were high-altitude welds performed above the Haihe River. Large changes in temperature and humidity brought considerable difficulty to the installation of the steel box girders.
The reporter learned during interviews that in order to ensure the installation quality of the steel box girders, special-shaped floating crane installation and precise positioning were adopted during the installation process, solving the difficulties of small working space and long lateral displacement distance in the erection of large-tonnage variable cross-section skew-curved bridge steel box girders with long spans and extra-wide decks. For the first time in China, the construction technology of large-tonnage, long-span fully welded steel box girders was adopted, solving the difficulties of welding deformation and steel box girder alignment control.