Study On The Seismic Performance Of Perforated Composite Block Walls With Structural Columns With Core Columns In Cold Areas Of Xinjiang

Xinjiang,which is located in northwest China and has a low overall economic level,is one of the provinces with very active earthquakes in China.In remote ethnic minority areas,people even live in traditional housing structures such as raw soil and stone masonry,which have defects such as low safety and poor durability.Based on the rich industrial solid waste resources such as fly ash and coal slag in the region and abandoned crop cotton stalk resources,the research team proposed a new type of hole-filled composite block wall.The wall is made of a new type of ceramsite hollow block as an external mold and industrial solid waste mixed cotton stalk fiber as an internal mold.It is a new type of composite block wall bearing load,environmental protection,energy saving and waste.It has a broad application prospect in village and town buildings.Based on the previous series of tests conducted by the research group,the seismic performance of this new type of composite wall filled with bored holes is studied,and the seismic performance of the composite wall filled with core-tie-column is tested and theoretically analyzed.The main work carried out in this paper and the results obtained are as follows:(1)Quasi-static test of composite block wall.A pseudo-static test was carried out on 10 composite wall specimens using factors such as vertical pressure,strength of the material for filling holes,the distance between cores,openings,and restraint methods.During the quasi-static test,the crack development of each wall specimen was mainly recorded,and the failure form of each specimen was analyzed.Based on the test data,analyze the seismic performance indicators of each characteristic point,including load and displacement,skeleton curve,ductility,stiffness degradation,relative stiffness degradation rate,and wall energy consumption.Concluded as follow:Increasing the vertical pressure can increase the ultimate bearing capacity of the wall;When the strength of the filling hole material is close to the strength of the external form block,the seismic performance of the wall is better;The decrease in the distance between core posts not only improves the ultimate bearing capacity of the wall,but also increases the ductility of the wall;Compared with the unopened wall,the bearing wall and the area of the hysteresis loop are greatly reduced,and the seismic performance is significantly reduced;The ultimate bearing capacity of the wall with the cast-in-situ structural column is greater than that of the wall with the core-column structural column,but the ductility of the two is relatively close;The ordinary sintered porous brick has a large bearing capacity,but its ductility and energy consumption are much smaller than those of the core pillar structure wall.(2)Establishment of restoring force model of composite block wall.In order to study the restoring force model of the wall,two forms of restoring force model,three types of polyline restoring force model,and research methods of restoring force model are summarized.In this paper,three influencing factors of vertical pressure,core strength and core-tie-column spacing are selected to establish a four-stage restoring force model.Firstly,the loading stiffness of each stage is calculated through the test data,and the model skeleton curve is compared with the test skeleton curve,and the agreement is good;Then,the unloadingstiffness expression is obtained through the stiffness degradation curve fitting analysis of the wall specimen.Finally,the hysteresis rule and loading path were determined,and the restoring force model of core block-filled composite block wall was established.(3)Study on seismic and shear capacity of composite block walls.In order to study the calculation formulas of the seismic and shear capacity of the wall,the failure forms of the masonry,the shear failure theory,the influencing factors of the seismic and shear capacity,related codes and the calculation formulas of the seismic shear strength proposed by domestic researchers are summarized.Taking compressive strength of inner-mold filling material,vertical pressure,and core-tie-column spacing as the main influencing factors,and fitting and analyzing the AW1-AW7 wall test data,the relevant parameters were determined.A calculation formula for the seismic shear capacity of this type of wall is established,and the calculated value of the shear capacity of the wall is compared with the experimental value.Conclusion: The calculated values of the shear capacity of the wall agree well with the experimental values.