12.07.2015 Views

Report - PEER - University of California, Berkeley

Report - PEER - University of California, Berkeley

Report - PEER - University of California, Berkeley

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

NEW MODEL FOR PERFORMANCE BASED DESIGN OF RC KNEE JOINTHitoshi SHIOHARA 1 and Yongwoo Shin 2ABSTRACTThis paper presents an application <strong>of</strong> the new theory <strong>of</strong> quadruple flexural resistance developedby the author for the performance evaluation <strong>of</strong> R/C knee joints. Ultimate capacity as well asfailure type are predictable by the model, if the dimension, geometry and material properties aregiven. The quadruple flexural resistance considers that joint panel consists <strong>of</strong> triangular segmentsdivided by four diagonal flexural critical sections in beam-column joints. The model usesequilibrium equations to relate magnitude <strong>of</strong> applied load such as column shear, beam shear andaxial force in column, to the magnitude <strong>of</strong> stress resultants on the critical sections. Failure criteria<strong>of</strong> concrete, steel, bond and anchorage are combined to predict the strength and failure type.While the model is applicable to beam-column joints with different configuration, includinginterior, exterior as well as knee joint, this paper focuses on correlation studies using test data <strong>of</strong>knee joints.Keywords: Analytical model; Knee joint; Strength; Failure mode; Beam-column joint.1. INTRODUCTIONThe evaluation <strong>of</strong> stiffness, strength, damage and ductility <strong>of</strong> beam-column joints is anindispensable for performance based earthquake resistant design <strong>of</strong> reinforced concrete(RC) moment-resisting frames. Recent design recommendations in codes provideupper limit for joint shear stress to preclude shear failure <strong>of</strong> beam-column joint basedon tests. Figure 1 compares configuration factors for joint shear capacity for US(ACI352 2002) and Japan (AIJ 1999). Design recommendations in the US and Japanrecognize that the joint shear capacity is significantly affected for different geometry,whereas New Zealand code does not request such reduction <strong>of</strong> joint shear strength.The value <strong>of</strong> configuration factors are such different in different countries, because theadopted reduction factors are empirical in general and no theory or mathematical modelsare available.1. Associate Pr<strong>of</strong>essor, Dept. <strong>of</strong> Architecture, Graduate School <strong>of</strong> Engineering, <strong>University</strong> <strong>of</strong> Tokyo,Tokyo 113-8656, Japan. Email: shiohara@arch.t.u-tokyo.ac.jp2. Graduate Student, Dept. <strong>of</strong> Architecture, Graduate School <strong>of</strong> Engineering, <strong>University</strong> <strong>of</strong> Tokyo,Tokyo 113-8656, Japan. Email: shin@rcs.arch.t.u-tokyo.ac.jp457

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!