| 요약2 |
In Seoul, more than 80 percent of residential buildings are constructed with unreinforced masonry(URM) buildings in early 1970 to 1990. In general, URM buildings have advantages of reducing the construction time and easy to construction. However, URM buildings do not have enough strength against the lateral force. Moreover, low rise buildings have not adopted seismic designs, and for that reason a critical damage is expected with an earthquake. The objectives of this study are 1) to find out the shear behavior of URM wall and the variables that affect the shear capacity of URM wall such as the aspect ratio and the thickness of masonry wall, 2) to propose an average shear strength and the equation of the shear capacity of URM wall by regression analysis using the test data with considering four kinds of failure modes, namely, rocking failure, sliding shear failure, toe crushing failure, and diagonal shear failure. The main variables are the vertical axial stress, the thickness, and the aspect ratio of URM walls. The test results show that the specimens, except the slender wall, are governed by rocking failure mode. The relationship of the shear stress and vertical axial stress is proportional to each other in square root. The relationship of the shear stress and aspect ratio is linearly proportional. A comparison of the results obtained by FEMA 273 equation and the proposed equation to the test data indicates that the proposed equation is compatible with the test results. As a final result, the ultimate shear stress of the URM walls in Korea is figured to be 2kgf/cm2. |