The Architectural Institute of Japan (AIJ) published its 1988 draft design guidelines for earthquake-resistant reinforced concrete buildings based on ultimate strength concept as a first attempt to develop an ultimate strength design procedure in Japan. This paper introduces the general concept of the design procedure, and explains in detail the design requirements and background information for reinforced concrete beam-column joints of the AIJ guidelines. Based on experimental evidence, the amount of lateral reinforcement in the joint required is significantly reduced from ACI requirements.

Presents a critical review of current design provisions for shear and anchorage in beam-column joints subjected to large seismic actions. When current design limits are compared with experimental data, the results indicate that if short anchorage lengths and large shear stress are used simultaneously, large losses of bond transfer capacity and stiffness will occur. The performance of joints based on different levels of joint shear stress and anchorage lengths is discussed, and an empirical formula linking anchorage and shear is proposed based on the limited tests data available on bar slip.

As part of a United States/New Zealand/Japan/China collaborative research project, interior and exterior beam-column joint subassemblages with floor slabs of prototype two-way and one-way reinforced concrete building frames were designed for earthquake resistance using the current New Zealand concrete design code, NZS 3101:1982. Three full-scale subassemblages as designed were constructed and tested under quasi-static cyclic loading which simulated severe earthquake actions. The overall performance of each subassemblage during the tests was satisfactory in terms of strength and ductility. The joint core and column remained essentially undamaged while plastic hinges formed in the beams. The strong column-weak beam behaviour sought in the design, desirable in tall ductile frames designed for earthquake resistance, was therefore achieved. Although the joint cores of the subassemblages remained in the elastic range, joint core shear deformations contributed significantly to the interstorey drifts. Also, a significant proportion of the slab bars in tension contributed to the negative moment flexural strength of the beams. The performance of the one-way joint was superior to the performance of the two way joints.

Geometrical configurations of reinforced concrete beam-column joints in actual building structures are quite varied because the configurations depend upon the number of structural members connecting the joints, the shapes of cross section of the members, the eccentricity among the axes of members, and so on. Focusing the interest mainly on the eccentricity from these factors, studies on seismic behavior of reinforced concrete interior beam-column joints in one-way frames with eccentricity are carried out with a classificatory examination, an investigation of a building destroyed by a strong earthquake, and a survey of previous studies and the authors' experiments. From the investigation of the destroyed building, it is suggested that the heavy eccentricity between columns and beams caused torsional moments in the columns and joints, causing severe damage. From the survey of three previous experiments in which one-sided eccentric joint specimens with wide columns and deep beams were subjected to lateral loading, it is shown that effective width and/or torsional moment should be considered for calculating the strength and stiffness of frames. Experimental results indicate that such eccentricities caused twisting of the columns and joints, resulting in reduction of the shear strength of the members. From the results of the classification examination and of the authors' tests in which five beam-column subassemblages with several types of eccentricity and beam width were subjected to cyclic lateral forces, it is observed that joints with one-sided eccentric beams suffer larger torsional moment around column axes, narrowing the effective joint width. Therefore, the shear cracking stress and the deformability of joints are reduced.

SP123 This volume is a collection of technical papers on the aspects of design of beam-column joints for seismic resistance. Nineteen papers are divided into the following groups. - Tests conducted on specimens designed using current codes but with the same general geometry and a specified loading history. (4 papers) - Design recommendations -- Japan. (1 paper) - Influence of joint geometry on strength and deformation characteristics. (8 papers) - Influence of bond on joint performance. (4 papers) - Joint in precast systems and with high-strength materials. (2 papers)