Mechanics Performance And Theoretical Analysis Of Steel Frame-prefabricated ECC Shear Wall Lateral Force Resisting System

Engineering fiber reinforced Cementitious Composite(ECC) is a new kind of construction material, which is a composite material with cement paste or cement mortar as the matrix and polyvinyl alcohol(PVA) fiber or polyethylene(PE) fiber as the reinforcing material. ECC has a range of desirable properties, such as high ductility, high toughness and high durability etc., which can significantly improve the seismic performance and the durability of the concrete structure and have broad application prospects in engineering structures. In order to improve the ductility of the prefabricated anti lateral force wall and to effectively reduce the losses caused by the earthquake, this paper proposes to improve the deformation capacity of steel frame filled with shear wall by the use of ECC, which prevents the premature withdrawal of work and significantly improves the seismic performance of the whole lateral force resisting system. The main research contents of this paper are as follows:(1) The mechanics performance research of the steel frame-prefabricated ECC shear wall lateral force resisting system. This paper carried out low cyclic horizontal reciprocating loading tests on the single-level and single-span steel frame test specimen and the single-level and single-span steel frame-prefabricated ECC shear wall lateral force resisting system test specimen. The failure mode, the energy dissipation capacity, the bearing capacity, the displacement ductility, the stiffness and other aspects of the two test specimens were contrastively and quantitatively analyzed. The improvement in the performance of the lateral force resisting system caused by the ECC lateral wall was also discussed. The test results show that the steel frame-prefabricated ECC shear wall lateral force resisting system achieves the goal as two defensive lines: the lateral force resisting wall, as the first defensive line, bears most of the horizontal shear stress during the early stage of load; with the increase of load, the wall has a direct shear failure and the steel frame, as the second defensive line, bears the main load. During the loading process, there are almost no dregs dropped from the ECC wall due to the mix of fiber, which shows a good integrality. Compared with the steel frame test specimen, the ductility, the peak load and the initial stiffness of the steel frame-prefabricated ECC shear wall lateral force resisting system are improved.(2) The nonlinear analysis of the steel frame-prefabricated ECC shear wall lateral force resisting system. With the finite element software ABAQUS, after choosing a suitable tension and pressure damage constitutive relation and the element model, the finite element model of the steel frame-prefabricated ECC shear wall lateral force resisting system was built, with which the nonlinear finite element analysis was carried out. The results show that the hysteretic curve from the finite element simulation and the experimental hysteretic curve matches well, which indicates that the nonlinear analysis model can well simulate the stress performance of the lateral force resisting system test specimen. The shear force and the bending moment of the wall were obtained with the finite element analysis software. The internal force of the prefabricated ECC shear wall was analyzed in detail and the wall was also designed. The analysis indicates that during the early stage of load, the share ratio of the lateral force resisting wall reaches more than 60% and with the increase of displacement load, the share ratio declines slowly; during the whole loading process, most of the overturning moment of the test specimen is assumed by the steel frame and the share ratio is above 80% until the test specimen is damaged and loses bearing capacity.