Construction Control System for Thousand-Meter-Scale Hybrid Girder Cable-Stayed Bridge Based on Double Target Control

To ensure the construction control of thousand-meter-scale hybrid girder cable-stayed bridges for high efficiency, precision, and safety, taking the Edong Yangtze River Bridge as a case study, research on the construction monitoring concept, monitoring method, and monitored parameters of the super-long-span hybrid girder cable-stayed bridge was carried out, and the construction control system for this complicated structure was built. The research and the system were based on theoretical studies, finite element numerical calculations with full consideration of the structural nonlinear geometrical effects, and the issues faced at the construction site. First, according to the construction control characteristics, problems, and challenges of thousand-meter-scale hybrid girder cable-stayed bridges, the double target control system was built based on the geometry control method. Then, focusing on the key aspects of this control system, some important issues such as the determination of the initial unstressed state amount, calculations pertaining to key construction members, fabrication and cast-in-site control stage, erection stage, and safety control in the construction stage were extensively studied, and the calculation and installation control methods were obtained. Finally, the entire construction control procedure for the Edong Yangtze River Bridge was carried out using this control system. The results show that the maximum alignment error at the top of girder is 16 mm, the axis error is 2.7 mm, and the cumulative girder error is 10.8 mm during the manufacturing stage. The minimum value of the nonlinear stability safety factor is 2.5 and meets the specifications. Meanwhile, the maximum alignment error of concrete girder in the side span is 11 mm, and the maximum alignment error of the steel box girder in the middle span is 157 mm. The relative error of the pylon deviation is L/12434. Furthermore, the maximum cable force error of a single cable located in the concrete girder is 4.5%, and the maximum cable force error of a single cable located in the steel girder is 6.30%. All the analyses show that the stress condition in the entire structure is reasonable, and all the monitoring indexes meet the specifications.