Shear Capacity Evaluation of RC Footing Beams With Large Web-Opening for Maintenance Based on Stress Transfer Mechanism

Abstract eng:
If the openings are made on the web of footing beams for the maintenance purpose, the shear capacity is reduced. The shear capacity design formula is absolutely needed for the seismic design. AIJ code [1] includes the evaluation of shear capacity around the web-opening. However, as it limits the opening’s diameter to less than 1/3 of the beam depth, the beam depth is sometimes determined by this limitation. Unnecessary large beam depth is not economical. Recently the footing beams with large web-opening of which diameter is more than 1/3 of the beam depth are experimentally discussed [2]-[7] and adopted in the structural design with aid of AIJ code [1]. The problems are that AIJ design formula [1] is an empirical equation and that it does not give the constant safety margin to the actual shear capacity. In this study, the shear force transfer mechanism around the web-opening was experimentally discussed, and the shear force transfer model was proposed. The diagonal bars form a truss structure and carry a part of shear force independently. The truss and arch mechanism of two stage beams upper and lower side of the opening carry the other part of shear force. The stirrups on the side of the opening balance with the strut of the arch mechanism. The shear capacity was successfully evaluated with the constant safety margin based on the proposed shear force transfer model.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket