Experimental Study On Seismic Performance Of Asymmetrical Masonry Structure With Reinforced Concrete Wall

Masonry structure has a wide range of applications because of its inherent superiority.Despite the reinforced concrete structure is now the trend instead of masonry structures,but now,in many urban housing renovation and construction of replacement housing,there is still large-scale use of masonry structures.Because of its low cost,excellent fire resistance,heat insulation,sound insulation,thermal insulation performance,simple construction operation,construction speed,more suitable for urban economic development.At the same time,in order to adapt to the development of the living standards of the residents,the town built the bottom of the masonry houses for the garage or warehouse.In order to meet the functional requirements of the garage,the need to open a large hole on the vertical wall,resulting in the vertical layout of the vertical wall,stiffness center and the quality center does not coincide with the problem,the seismic performance of the structure adversely affected.In order to solve the above problems,this paper proposes a method of replacing the masonry wall with reinforced concrete shear wall(reinforcement wall)according to the principle of equivalent stiffness.Since the lateral stiffness of the same section reinforced concrete walls more than a large masonry wall,which can reduce the width between the hole,to meet the requirements,but it needs to do in-depth study of the seismic performance.This paper has produced a set of reinforced concrete to strengthen the wall of the plane irregular masonry structure model,model scale ratio of 1: 4.Through the quasi-static test of the model,the failure mechanism and mechanism of the structural system are studied,which provides the experimental basis for the structural design of the house.The conclusions drawn from this study are as follows:1.For the bottom of the garage for the outer wall of the vertical wall of the masonry structure of the housing,by setting the stiffness of the reinforced concrete reinforcement wall(shear wall),can be a good solution to the irregular layout,stiffness center and quality center is not Coincidence of the problem.,to avoid the structural stiffness due to uneven torsion effect.2.The upper load can be effectively transferred to the shear wall,the shear wall and the upper masonry structure can work well together.3.With the increase of the load in the horizontal direction,the degree of damage of the concrete shear wall and the masonry wall is different and the lateral displacement stiffness is different,which will change the stiffness center of the structure and produce a certain torsion effect.But this effect is small,can be ignored.4.The reinforcement wall at different locations has different forms of damage,and the reinforcement wall in the middle of the house is the shear-like failure.The cracks on the wall are mainly diagonal.And set at both ends of the shear wall is mainly produced by the level of cracks,damage in the form of normal section damage.5.With the increase of load,the damage of the two-story wall is more serious than that of other layers,and the decrease of stiffness is the largest,and the lateral displacement increases the fastest.In the structure design should pay attention to the one-floor and the two-floor stiffness ratio,try to avoid the emergence of weak floor.6.The existence of the overall performance of housing,in the horizontal seismic load when there is the overall bending moment.In the overall bending moment,due to the low tensile strength of masonry,mainly by the "tension zone in the shear wall,structural column" bearing tension,resulting in a different position in the shear wall has a different state of force.With the increase of load,masonry wall damage,the internal force of the shear wall will also change.7.Under the action of horizontal load,the strengthening mechanism of reinforced wall and connecting beam is similar to that of multi-limb reinforced concrete shear wall structure.8.In the case of horizontal seismic load,the structural column plays an important role in improving the integrity of the structure and increasing the shear bearing capacity.9.Before the wall is cracked,the structural column and the masonry provided in the wall are co-stressed for the whole wall.With the increase of load,the masonry is destroyed,the role of the structural column becomes more and more obvious.The effect of the whole wall is reduced,and the structural column is used as a separate component to produce bending moment in the structural column.10.The structure of the system with the ordinary brick and concrete structure of the same form of destruction,there is a certain capacity of seismic energy consumption,there will be no brittle collapse.11.For the masonry structure of the building wall,the seismic action can be calculated according to the bottom shear method.Then,according to the lateral stiffness of each masonry wall and the strengthening of the lateral wall stiffness of the wall,the total shear force of the bottom layer is distributed to each masonry wall and the total reinforcement wall.The internal force of each stiffening wall and connecting beam can be calculated by the multi-limb shear wall with concentrated load on the top of the reinforcement wall.In the calculation of the bearing capacity of the section,the calculated internal force of the reinforcement wall should be increased appropriately.