NONLINEAR EARTHQUAKE RESPONSE ANALYSIS OF REINFORCED CONCRETE SPACE FRAMES

This paper represented the analysis investigation on nonlinear earthquake response of reinforced concrete space frame structures under bi-directional lateral earthquake motions by taking account of interaction between bi-directional bending and varying axial force in columns caused by overturning moment on structures. Three reinforced concrete space frames were analyzed, which were designed to yield in either of beams and columns. The analysis results indicate that the axial force-bending moment interaction affects significantly the response of members, especially exterior and corner columns which directly subjected to fluctuant axial load. Compared the uniaxial re-sponse with biaxial response, the individual member response can not be exact-ly determined by uniaxial response, but the overall responses (floor lateral displacement and story shear) represented by the root of the square sum of the uniaxial responses in X and Y directions are not much different from the vector maximum by biaxial response provided that the frame structure does not form a story-yielding mechanism.