| A large number of full scale and reduced scale specimens subjected to static or dynamic load are carried out to research the in-plane affects of infill wall to the frame structure by national and international researchers and a relatively complete theory system has been established. However, the out-of-plane stability of infill wall is considered rarely, furthermore, its calculation method and feasible measures have not been investigated. As a kind of nonstrucrural component, infill wall in frame is often constructed with construction requirements without considering any seismic calculation. The earthquake disasters show that the loss caused by the collapse of nonbearing components was too heavy. The regulations of Code for seismic design of building (GB50011-2001) is improved a lot, for example, the rule of material selection and structure layout are confined in 13.3.1 and 13.3.3. Also it proposes that flexible connection should be used between infill wall and column which can ensure the in-plane and out-of-plane seismic performance of infill wall in theory. However, the requirement doesn’t include the practice details for so many years and the study in this field is so little. In China, even though it is made clear that infill wall in frame should connect frame beam tightly in "Code for seismic design of building GB50011-2001", still there are not any practical measures concluded. The problem that infill wall can change the stiffness and reduce the national vibration periodof structure still is not resolved. Thus, the reasonable connection between infill wall and beam or column is an urgent problem.In this paper, the main results obtained are as follows through the shaking table test of 1:3 scale models, numerical analysis and the research of connection details.(1) The out-of-plane stability of infill wall in frame had been researched with the shaking table test of single-layer, two-layer and four-layer specimens to explore the seismic performance of infill walls under different conditions. The results show that the infill walls which connected with the frame by steel bars and keep a gap are better than others obviously, and the walls connected with the frame by steel bars but without gaps aren’t as well as the former ones. In addition, walls filled with inclined bricks on the top are destroyed under the large earthquake, and the disengaged ones have poor performance during the test.(2) Numerical calculation and analysis indicated that the steel bars between the infill wall and frame have obvious effect to the free boundary of the wall. The alternative of steel bars’diameter and the thickness of gaps between beam and wall haven’t essential impact to the wall’s fundamental frequency. The infill walls connected by steel bars with the frame have high fundamental frequency, which generally vibrating with the main structure and do not cause the secondary vibration. Therefore, the measures connected with the frame by steel bars and keep a gap are proposed.(3) When the steel bars between infill wall and beam are valid, the computational model of masonry infill wall can be simplifieed as built-in beam at both ends, which result can both simplify the calculation and satisfy to the precision of buildings.(4) Based on the design idea that there could remain gaps or without gaps between infill walls and the frame, the structural analysis of internal forces and bearing capacity of the infill walls are researched. Then bearing capacity calculation formula of the steel bars and the seismic calculation of infill walls are prorosed on the base of total cross section theory. Also, the practical measures are discussed and the corresponding construction requirements are suggested. |
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