Stress control method for concrete pouring construction of continuous CFST tied arch bridge: Calculation method and actual bridge case

When the concrete in the tubes of a continuous concrete-filled steel tube (CFST) tied-arch bridge is being grouted, if the grouting sequence is not reasonable, problems such as excessive tensile stress of the bridge piers and repeated tensioning of the tie rods will occur, which seriously affects the structural safety and construction speed. It is indeed a method to repeatedly conduct trial calculations through the finite element method. However, this method has a large amount of calculation and low efficiency, and the final calculation result may not be the optimal solution. This paper aims to ensure that no tensile stress appears in the bridge piers during the concrete grouting process in the tubes. Based on the stress influence line, a calculation method for the feasible region of the tension force of the tie rods, the tensioning time of the tie rods, and the grouting sequence of the concrete in the tube are proposed. Firstly, the stress influence lines of the pier during concrete pouring in different tubes are obtained, and then the stress values of the pier during concrete pouring in tubes are obtained. Combined with the influence of the tension force of the tie rod on the stress of the bridge pier, the calculation formula for the feasible region of the tension force of the tie rod was derived, and the tensioning timing was determined. At the same time, the optimal pouring sequence can be determined according to the influence of different concrete pouring sequence in the tube on the pier stress. Finally, the engineering monitoring data was employed to verify the reliability of the method, and an analysis was conducted on how the structural parameters affect the force acting on the bridge pier. This method can significantly reduce the blind trial computations in the finite element method and guaranteeing the safety of the bridge throughout the construction process.