Experimental Study Of Seismic Performance Of Low Strength Masonry Walls Reinforced With One-Side Cement Mortar Splint

In China, there are large numbers of masonry buildings, which are seismic vulnerable and should be considered for strengthening. Strengthening with cement mortar splint is one of the most common methods of masonry structure reinforcement. It is allways cofusing that the different results could be given while we separately use the different calculation formulas for shear capacity of the strengthened masonry wall in two codes:Code for Design of Strengthening of Masonry Structure (GB 50702-2011) and Technical Specification for Seismic Strengthening of Buildings (JGJ 116-2009). Due to the limitation of the test condition, experimental studies on cement mortar splint reinforced masonry wall in the 1970s and 1980s were usually carried out with the diagonal or monotonic loading method which was difficult to fully assess the influence of cement mortar splint on seismic performance of the strengthened wall and hardly reflects the various potential failure modes of masonry walls in the earthquake. Therefore, it is urgently necessary to provide some reliable conclusions for revision of the code based on the mass experimental results and comprehensive analysis on the masonry wall strengthened with cement mortar splint.A total of 30 low strength masonry wall panels were tested in the in-plane direction using quasi-static cyclic loading. The conclusions are reached concerning the influence of the strengthening with one-side cement mortar splint on following properties of these low strength masonry walls:failure mode, strength capacity, deformation capacity, ductility coefficient, energy dissipation capacity, etc.Based on the results from the experiment above,96 finite element models with various parameters such as vertical compressive stress, thickness and mortar strength have been established to investigate the effects of these factors on the low strength masonry wall reinforced with one-side cement mortar splint.Collected a large number of formulas calculating the shear capacity of masonry wall strengthened with cement mortar splint, but these formulas have poor applicability to the low strength masonry wall reinforced with one-side cement mortar splint by verifying those formulas based on the experimental data in this article. Therefore, an improved formula was proposed, which might be more applicable to shear capacity calculation of the strengthened wall. Furthermore, compared the strength and stiffness enhancement factors of the strengthened walls in the experiment to those specified in the code, the more reasonable enhancement factors and formula about the relationship between wall thicknesses to the enhancement factor are given through analyzing the possible weaknesses of current codes.Summarized the available research findings about the failure modes of unreinforced masonry wall under the different conditions, and verified the applicability of those theories to low strength masonry wall based on the experiment results in this article; and on this basis, the study presents the method to judge the failure mode of low strength masonry wall reinforced with one-side cement mortar splint. Finally, some suggestions are proposed on strengthening low strength masonry wall with one-side cement mortar splint.