Study On Feasibility Of Reinforced Concrete Longitudinal Frame-shear Wall And Transversal Shear Wall System In Residential Buildings

Shear wall system is widely used in the multi-story and high-rise residential buildings.As the Chinese code requires shear walls be place in both longitudinal and transversal directions,also limited by the span of slab,the spacing of the walls is limited.As a result,the flexibility of the usable space is low and it is hard to generate large open space.As the improvement of life quality,there has been higher and higher requirement on the flexibility and comfortability of living spaces.In this paper,by removing longitudinal shear walls as much as possible and replace them with moment frames,while keeping the shear walls in the transversal direction,the author define a mixed structural system which has longitudinal frame-shear wall and transversal shear wall.This structural system provides higher flexibility of architectural spaces and better suits the living requirements of the people.To verify the safety of this system,this paper modeled a group of residential buildings of 6 levels,12 levels and 24 levels,both with the traditional shear-wall system and the new longitudinal frame-shear wall and transversal shear-wall system with SATWE software,and compared the analysis results including periods,story shears,shear-weight ratios and inter-story drifts.The results show that the proposed new system meet the requirements in the Chinese code.In order to evaluate the effect of slab out-of-plane stiffness on the lateral stiffness of the structure,comparison studies were done for the 6-level,12-level and 24-level buildings.The slab is modeled using membrane elements and shell elements,respectively.The results show that the out-of-plane stiffness of the slab affects the lateral stiffness of the structure significantly.Pushover analyses are then done for these models of shear wall system and longitudinal frame-shear wall and transversal shear-wall system,using the elasto-plastic analysis software PUSH&EPDA developed by CABR.The analyses are based on the actual reinforcement given by SATWE,and use the standard material strength of concrete and rebar.The pushover loads are assumed to be in a reverse triangle pattern,and loaded in X and Y direction,respectively.The relationship between the capacity spectrum and the demand spectrum under frequent,moderate and rare earthquake have been investigated for both types of structural systems.The story shears and inter-story drifts are also investigated and compared.The plastic hinge developmentprocess is also investigated and compared.The results show that the maximum inter-story drifts in rare earthquakes meet code limit.The plastic hinge distribution also show that the structure meet the ‘no collapse in rare earthquake' requirement by the code.This that the structural design with frame-shear wall in one direction and shear-wall in the other direction is safe and feasible.