Continuum Analysis of Unstiffened and Stiffened Coupled Shear Walls

[摘要] The basic approach of the continuum analysis of coupled shear wall structures subjected to lateral loads has been reassessed, and a discretisation of the method has been established. It has been demonstrated that consistent results are achieved for the case of equal walls on identical supports. Inconsistencies occur in the traditional theory if the walls are unequal. A top concentrated interactive force is found to exist in the connecting medium at the top of the structure, and statical conditions may be violated. Although good results are still obtained for slightly unsymmetrical shear wall structures, the accuracy falls sharply when the unsymmetry of the structure becomes important, especially in the extreme case of a wall connected by beams to a column. For such cases, the results given by the continuum method show very poor agreement with those given by an accurate stiffness-matrix frame analysis if the conventional assumption of a line of contraflexure occuring at the mid-span position of the lintel beams is adopted. It is found that a revised analysis using a modified line of contraflexure greatly improves the accuracy of the results obtained for the forces in the slender wall, and also reduces the intensity of the top fictitious force. Guidance on the best method of modelling for an analysis by the continuum method is presented. A revised line of contraflexure is adopted, and guidance on the incorporation of the top boundary condition is established. Best results for the internal forces are achieved if the revised line of contraflexure is used, provided the top boundary condition is properly considered, and if the beam moment is distributed equally between the stories above and below the level concerned in the discretisation procedure. The continuum analysis for coupled shear walls is extended to cover the inclusion of one or two stiffening beams along the height for walls supported on elastically flexible foundations. Good agreement is obtained between the results given by this extended method and those from the frame analysis. Where stiffening beams are provided to enhance the rigidity of the structure, best results are obtained when the two stiffening beams are located at roughly one third and two thirds of the height of the structure. In the case of one stiffening beam only, the best location is between one third and one half of the height of the structure.

[发布机构] University:University of Glasgow

[关键词] Civil engineering