Study On Seismic Behavior Of Monolithic Precast Concrete Shear Wall Structure With High Axial Compression Ratio

The monolithic precast concrete shear wall with rebar overlapped in pre-reserved area is a kind of shear wall structure in which concrete post-pouring area is set at the bottom of the wall.It is possible to make overlapping connections of rebar between prefabricated parts in the reserved area.Although this construction method increases the amount of wet work in the construction site,it improves the integrity of the precast concrete shear wall,reduces the number of sleeves,ensures the quality of steel connection,and reduces the difficulty and cost of construction.In this paper,the experimental study and finite element analysis of the monolithic precast concrete shear wall with rebar overlapped in pre-reserved area under the action of high axial pressure ratio are carried out.3 groups including 9 piece of full-scale specimens are designed and produced to conduct pseudo static test.The similarities and differences between precast specimens and cast-in-situ specimens in crack development and failure modes are analyzed.The seismic behavior and mechanical property of the precast shear walls,such as hysteretic behavior,skeleton curves,bearing capacity,deformation capacity,stiffness,energy dissipation,are studied and compared to their cast-in-situ counterparts.Based on the finite element analysis software and the mechanical characteristics of the joints of precast shear walls,a method is proposed to simulate the shear bearing capacity of joints with concrete the bonding,friction and steel pin force.The monotonic loading model of monolithic precast concrete shear wall is established.The seismic performance of shear wall is evaluated by comparing the test results.And the influences of axial compression ratio and ratio of shear span to effective depth on the mechanical properties and failure modes of shear walls are analyzed.In this paper,the mechanical and seismic properties of the monolithic precast concrete shear wall are studied through tests and finite element simulation,and the conclusions are as follows:(1)The failure modes and patterns are similar between precast and cast-in-place specimens.Both precast and cast-in-place specimens develop a flexural shear failure.The reinforcements are yield or facture in the edge members.The concrete on the corner is collapse and the bottom of precast shear wall cracks.These failures cause capacity dissipation of specimens.The monolithic precast concrete shear wall with rebar overlapped in pre-reserved area has same hysteretic behavior,capacity,ability of energy dissipation,seismic behavior,mechanical property,and stiffness with cast-in-place shear wall.Both precast and cast-in-place shear wall specimens have good deformation capacity and meet the code demand.(2)The precast specimens would separate with grade beams under the loading test.Inclined cracks and splitting occur along the grouted dowels because of horizontal and vertical gaps and grouted dowel in precast specimens.These phenomena do not have obvious effect for the mechanical properties of precast specimens,and have minor effect for the development of cracks,the load path,and the integrity of specimens.(3)An idealized finite element model is conducted.The analytical results have similar capacity and load-displacement curve with experimental results.The plastic strain and the damage of compression of the concrete in the numerical model show the failure position and modes of the monolithic precast concrete shear wall with rebar overlapped in pre-reserved area.(4)Under the action of high axial compression ratio,the precast concrete shear wall with rebar overlapped in pre-reserved area can still achieve the performance requirements of monolithic precast concrete shear.Reducing the shear-span ratio will have an adverse effect on the whole performance of the shear wall.The improvements of precast shear wall have been conducted according to the effects of hear compression ratio and axial compression ratio.