Compressive Mechanism And Confining Effect Of Brick Masonry Column Strengthened By Steel Angles

The reinforcement method of brick masonry columns strengthened by steel angles at the four corners is a mature reinforcement technique.The advantage of this method is that it can significantly enhance the bearing capacity,section stiffness and ductility without changing the section size of original brick masonry column.Easy construction and short construction period is another superiority of the method.The bearing capacity of strengthened member by steel angle is usually derived from the addition of bearing capacity of steel angles and original brick masonry column.And the interaction between steel angles and original brick masonry column is neglected.However,the epoxy resin or cement is often used to connecting the steel angles to the brick masonry column.In this way,the brick masonry column is confined by steel angles at the four corners,and this confinement will result in the increase of the strength of brick masonry columns.At the same time,the stabilization of steel angles is improved by horizontal supporting provided by the internal brick masonry.Compressive mechanism and confining effect of brick masonry columns strengthened by steel angles was systematically studied by numerical simulation and theoretical analysis in this paper.The main study is the effect of ferrule effect on bearing capacity of internal masonry and the local stability of steel angles improved by internal masonry.The primary work is as follows:(1)The three-dimensional numerical model of brick masonry column strengthened by steel angles was established using the finite element software,ANSYS.The material nonlinear constitutive equation and the contact behavior between steel angles and brick masonry column is considering into the numerical model.The numerical model was validated by the comparison between the analytical and the experimental results.(2)The influence of thickness,slenderness ratio,section size,strengthen of steel material,strength of masonry material,spacing of batten plate,slenderness ratio and eccentricity on loading process and compressive mechanism of brick masonry column strengthened by steel angles according to the established numerical model.The effect of different parameters used in the numerical model on ultimate bearing capacity,ductility and lateral deformation were analyzed.(3)The effects of hoop on different specimens were analyzed terms of numerical results,and the calculation formula of masonry strength considering the confinment of steel angles was presented.A calculation formula of axial compression bearing capacity for the brick masonry column strengthened by steel angles was proposed.Comparing with results of numerical analysis and computation value of the specification formula the proposed formula that takes into account the interaction between steel angles and masonry column is higher accuracy.(4)Considering the compressive strength and bonding stiffness coefficient of brick masonry,the local buckling performance of steel angles was studied adopting the energy method.A formula buckling coefficient for steel angles was deduced to reveal the influence rule of the compressive strength and bonding stiffness coefficient on the buckling coefficient for steel angles.