Research on temperature control techniques for mass concrete in the pile cap of the west tower of Shiziyang Bridge

Abstract With the continuous advancement in the construction of long-span bridges in China, the application of mass concrete bearing platforms has significantly increased, rendering temperature control a critical technical challenge. The Shiziyang Bridge project features a double-deck steel truss suspension bridge with a main span of 2 180 m. Its main pier employs separated bearing platforms, each circular in plan with a diameter of 40 m and height of 9.0 m. Constructed using C45 concrete, each platform contains over 10,000 m 3 of concrete. To mitigate thermal cracking risks and enhance crack resistance, this study implemented comprehensive temperature control strategies through Midas FEA finite element analysis and intelligent field temperature monitoring systems. Key findings revealed that both numerical simulations and field measurements demonstrated the effectiveness of cooling pipe arrangements with horizontal spacing of 100 cm and vertical spacing of 80 cm in reducing thermal gradients. The minimum crack resistance safety factor calculated through finite element methods reached 1.47, exceeding the specified limit of 1.4 and satisfying stress control criteria. Field monitoring recorded a maximum internal temperature peak of 64 ℃, with maximum internal-surface and surface-ambient differentials of 23.4 ℃ and 19.8 ℃ respectively, all complying with design specifications. The intelligent temperature control system successfully achieved precise regulation through automated cooling water flow adjustment, temperature monitoring, and directional water flow reversal, thereby ensuring the realization of seamless bearing platforms for the western pylon of Shiziyang Bridge. This technical approach provides valuable references for thermal management in mega-scale concrete structures, demonstrating that integrated numerical simulation and intelligent monitoring can effectively control hydration heat effects while maintaining structural integrity.