Improvement of Strength Reduction Factor Related to Opening Height for Rc Shear Walls

Abstract

This study aims at improving a strength reduction factor r 3 related to opening height for RC shear walls in the AIJ design standard. FEM analyses for RC shear wall specimens with vertically aligned openings were conducted to evaluate contributions of the wall components to the overall lateral strengths. As a result, the flexural resistances of the partial walls divided by the openings were overestimated by r 3 , while the shear resistances of the beams between the openings agreed with those by r 3 . Therefore, a new strength reduction factor new r 3 was proposed on the basis of a flexural strength reduction index for this type of wall. Consequently, the estimations for the ultimate strengths of the above specimens using new r 3 showed good agreements with the experimental strength reductions.

Experimental evaluation of the structural performance of foundation beams under RC shear walls with door openings

“…The ultimate shear strength evaluation method from Ref. [13] was in agreement with the measured shear strength of the beam specimen. 5 The effects of the wall thickness, compressive strength of the concrete, and the ratio of the longitudinal wall reinforcement were found to lead to a change in the critical face position of the foundation beam.…”

“…The ultimate shear strength evaluation method from Ref. [13] was in agreement with the measured shear strength of the beam specimen. The effects of the wall thickness, compressive strength of the concrete, and the ratio of the longitudinal wall reinforcement were found to lead to a change in the critical face position of the foundation beam. The critical face position of the foundation beam on the tensile column side of the shear wall was located approximately 0.1‐0.3 times inside the beam depth from the opening end.…”

“…Static loading tests 10‐12 and two‐dimensional FEM analyses 13 were conducted using three‐story specimens to verify the accuracy of Eqs. () and ().…”

“…The failure mode was flexural failure at the bottom of the two wall panels separated by the door opening and shear failure of the beams between the upper and lower openings. The measured strength of the walls could be evaluated considering the flexural strengths of the two wall sections and shear strengths of the beams 13 …”

“…The measured strength of the walls could be evaluated considering the flexural strengths of the two wall sections and shear strengths of the beams. 13 In the abovementioned studies, a rigid foundation stub was attached to the bottom of the shear walls with door openings. That is a foundation beam with high strength and high rigidity was used.…”