Research On Vertical Axis Force Loading Control And Specimens Design And Analysis Of Masonry Shear Wall Experiment

In this paper, we researched the seismic disaster mitigation of masonry shear wall, and it is a subject of the Natural Science Foundation of China (Project Grant No.:50978177).In order to exert the vertical axis force more precisely in the compression and shear static test, we have made static test aimed for unreinforced masonry walls, and the theoretical analysis, studied the issue that there are big deviations when we exert constant vertical load to the wall, and reached that it is Inappropriate that there is no spin and to maintain the vertical load unchanged in the test. We looked for the reasons why there are big deviations from principles of hydraulic jack, regulator control theory, and the relief valve itself to improve the vertical load control devices and load methods. We reach the conclusion that we could avoid the additional eccentric moment if using the synchronous self-locking hydraulic jack of same oil road, we could meet the demand of constant load and the accuracy that the test needs, if we install the electronic proportional relief valve and the hydraulic lock of the loading device. We could decrease the failure rate of the relief valve and increase the regulator performance by protecting the relief valve. We could increase the accuracy by choosing the appropriate level of the pressure gauge that hydraulic jack supported.The main factors that affect the damage forms of Masonry shear wall are: masonry strength, high aspect ratio structures and axial compression ratio, the level of reinforcement and structural columns, etc. In order to study the affections that the aspect ratio, horizontal bar and the central structural column made to the capacity of specimens and the capacity of carrying, we designed of specimens of masonry shear wall with different shear-bending damage forms, and studied the Failure mechanism, the shear capacity of flexural carrying capacity and deformationIn the cyclic horizontal load, compared with the central structural column, the level of non-reinforced brick masonry walls and unreinforced masonry construction wall column. We designed and drew the details of the size and reinforcement of the specimen, calculated the amount of the materials and the mix ratio, made detailed steps of specimens production, determined the loading devices and installation methods, cleared the testing projects and the positions, and determined the loading system, in order to prepared for Brick masonry shear wall static Testing.We analyzed the specimens to study the cracking forms and damage characteristics that the specimens under the level cyclic loads and vertical loads. We also made theoretical analysis and nonlinear finite element analysis of the affections that the aspect ratio, the central structural column and the level of reinforcement to the masonry shear wall. Compared the shear capacity and the flexural capacity of the specimens, we reach the conclusion that the shear specimen and the bend-type specimen designed would reach the expected damage forms. Make sure that the size and the reinforcement are reasonable and precise, in order to make full preparation for the seismic test. Compared with the ultimate bearing capacity and the development of the crack of specimens with different aspect ratio, We reached the conclusion that with the increasing of the aspect ratio, the wall turns from shear damage into bending damage, the lateral capacity in shear damage is far more than that in bending damage, the ductility in bending damage is far more than that in shear damage, so the aspect ratio has a big affection on the capability of the masonry wall. A reasonable aspect ratio could raise the deformation and the lateral load, Improve the seismic performance to decrease the damage. By analyzing the ultimate bearing capacity and the development of the crack of the specimens with the central structural column and horizontal mortar joint reinforcement, we concluded that the central structural column can effectively limit the development and the perforation of the main crack, increase the deformation and the ductility of the wall, horizontal mortar joint reinforcement help the specimen to shear, slow down the development of the crack, the central structural column and horizontal mortar joint reinforcement can help to prevent the brittle fracture, increase the ultimate bearing capacity, so, they are effective seismic measures.