Effect Of Vertical Compressive Stress On Seismic Performance Of Load-bearing Horizontal-hole Interlock Concrete Block Walls

For the masonry structure houses in villages and towns,our research team developed a load-bearing horizontal-hole interlock concrete block for the masonry structure bearing walls.The block has a good masonry quality,low technical requirements for workers,fast construction speed,thermal insulation,saving mortar and so forth.Under the earthquake,the load-bearing wall will be affected by both the vertical compressive stress generated by gravity and the shear generated by the earthquake,additionally the vertical compressive stress has a significant effect on the seismic performance of the walls.Therefore,in this paper,tests for seismic performance of load-bearing horizontal-hole interlock concrete block walls were conducted,and with the finite element numerical simulation,the normal stress influence coefficient of seismic shear strength of load-bearing horizontal-hole interlock concrete block walls was studied.Firstly,two load-bearing horizontal-hole interlock concrete block full scale walls with structural columns were made,and the walls size are 2750 mm × 2640 mm × 240 mm.The low-cycle repeated loading test was carried out with vertical compressive stress of 0.3MPa and0.6MPa,respectively,to investigate the impact of seismic performance under vertical compressive stress.It is indicated that the increase of vertical compressive stress lead to increasing cracking load,peak load,initial stiffness and stiffness degradation rate,and effectively restraining the slip and shear deformation of wall,but reducing the displacement ductility coefficient and energy dissipation.Secondly,the finite element analysis was conducted using ABAQUS to build integral modeling of load-bearing horizontal-hole interlock concrete block walls,after the material constitutive relations and related material parameters were determined.The error within 20% of peak load was obtained by compare the finite element results with the test results,which show the finite element model was capable of predicting accurately peak load of load-bearing horizontal-hole interlock concrete block walls.Finally,the numerical simulation with different vertical compressive stress loaded onload-bearing horizontal-hole interlock concrete block walls which were built with mortar of three different strength grades was conducted.The expression for calculating the normal stress influence coefficient of seismic shear strength of load-bearing horizontal-hole interlock concrete block wall was fitted with the data obtained from the stimulation.Results show that the normal stress influence coefficient of the seismic shear strength of load-bearing horizontal-hole interlock concrete block wall should be appropriately reduced.