An Autoclaved aerated concrete (AAC) is an efficient structural material. In this study, effect of an opening to a bearing wall in the elastic region was confirmed for structural design of AAC block masonry structures. While the stiffness reduction factor for reinforced concrete box-shaped wall structures (WRC structures) has been proposed, it is unknown that the reduction factor of the WRC structure adapt to the AAC block masonry wall. Therefore, failure mode and the stiffness reduction factor were confirmed by in-plane shear tests on masonry bearing walls with openings. Moreover, FEM analysis in the elastic region was performed and compared between the experimental test results and the analytical results. Finally, FEM analysis on the bearing wall with some opening configurations was performed and an equation of stiffness reduction factor due to opening configurations for the AAC masonry structure referring to the experimental test results and the analytical results was proposed.
A suite of three masonry bearing walls which have different opening configurations was tested by using a test setup of cantilever system. In the test result, integrated wall behavior was observed as the bearing walls without openings. Moreover, usability as bearing walls was confirmed because a little cracking and elastic behavior were observed until 1/1500 rad. Shear failure mode or shear failure mode after yielding was observed and a sharp post-peak drop was observed in the specimen of shear failure mode. Therefore, it is assumed that sufficient shear reinforcements are placed in lintel beams and side walls of openings in case of actual structural design.
FEM analysis in the elastic region was conducted in order to compare the FEM analytical results with the experimental test results on bearing walls without openings and with ones. AAC blocks and grout constituted a continuum except reinforcements and its mechanical property was obtained from the compression and shear wallette tests1). Since the stiffness obtained from the FEM analysis shows good agreement with the stiffness obtained from the experimental tests at 1/1500 rad., it is assumed that the FEM analysis model is appropriate in the elastic region.
FEM analysis on bearing walls with some opening configurations was carried out. Stiffness reduction factors obtained from the FEM analysis results and experimental test results are lower than ones for WRC structure. Therefore, the stiffness reduction factor r1’ for the AAC block masonry structures which was calculated from the experimental test results and the FEM analytical results was proposed. However, further consideration will be needed to yield any findings because of a limited number of opening configurations in this study.
