Numerical simulation on the mechanical property improvement of prefabricated subway station containing prestressed steel strand joints

Abstract Prefabricated construction technology has been widely used in the construction of subway stations due to the advantages of excellent material quality, short construction periods, and low environmental pollution, but the joint is the weakest area of prefabricated structures under environmental load. To further enhance the joint mechanical properties, a 3D finite element model of prefabricated subway stations containing prestressed steel strand joints is established; the cooling method and concrete plastic damage constitutive model are adopted to simulate the prestress effect and concrete cracking. Based on numerical simulation, the bending stiffness and shear stiffness of prestressed steel strand joints are compared to bolted joints, and the deformation and damage mechanics of prefabricated subway stations containing different types of joints under surface overloads are studied. The results show that replacing bolted joints with prestressed steel strand joints can significantly improve the joint bending stiffness and shear stiffness. When the prestress of steel strands increases to 120 kN, the maximum vertical displacement reduction rate of the joint will reach 52%. For the prefabricated subway station structures, replacing bolted joints with prestressed steel strand joints will not affect the joint deformation development trend but will change the distribution law of internal forces. When the prestress of steel strands is 80 kN, the maximum vertical and horizontal deformation reduction rates will reach 36% and 38%; the larger the surface overload, the more significant the decrease.