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In May of 1993, approximately twenty researchers and five representatives from construction firms met in Kyoto, Japan, for the First Multilateral Meeting on Structural Performance of High-Strength Concrete in Seismic Regions. Four countries (United States, Japan, New Zealand, and Australia) were representated at the meeting. The 3-day meeting divided into eight sessions covering current research programs and applications of high-strength concrete in the respective countries. The objectives of the meeting were to exchange information and to develop a coordinated program for further information exchange, evaluation of information, and development of design guidelines for the use of high-strength concrete in seismic regions. The follow-up meeting was held in November 1994 in Honolulu, Hawaii, and was attended by twenty seven participants from the US, Japan, Canada, New Zealand and Hong Kong. The Second Multilateral Meeting on Structural Performance of High-Strength Concrete in Seismic Regions consisted of thirteen sessions. Six of the sessions concentrated on the following behavioral topics: bond and anchorage, confinement, flexural members, axially-loaded members (columns and walls), beam-column joints, and shear and torsion. An additional session was devoted to presentation and discussion of design concepts and applications of high-strength concrete (HSC) in seismic regions. The remaining six sessions consisted of large and small working group sessions. During the small group sessions, participants were divided into groups of five to ten members to discuss the results of the previous sessions. Summaries of the small working group were then presented to the entire group fro additional comments and conclusion during the large working group sessions. This ACI Symposium Publication comprises selected papers which were the outcome of the Second Multilateral Meeting on Structural Performance of High-Strength Concrete in Seismic Regions. The working group discussion summaries are also included in this special publication. The editors are appreciative of the eforts of the authors and reviewers of these papers. The cooperation of the authors in the careful revision of their papers in accordance with the reviewers' comments is greatly appreciated. Note: The individual papers are also available as .pdf downloads.. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP176

A total of twenty one high-strength reinforced concrete shear wails were tested as a part of a five-year national research project in Japan. Concrete with compressive strength ranging from 60 MPa to 120 MPa, and reinforcing steel with grades ranging 700 MPa to 1200 MPa were used for one-quarter scale specimens. The loading conditions and the reinforcement ratios were systematically varied to observe the strength and deformation capacities attained in various failure modes, such as flexural failure and shear failure before or after yielding. This paper summarizes the test results as well as the results of other tests on high-strength reinforced concrete shear walls conducted in Japan. Design equations for flexural and shear strengths based on the resistance mechanisms are verified through evaluation of experimental data. Methods of estimating the yielding deformations and the ultimate deformation capacities at web-crushing are also discussed.

Current US seismic-resistant design provisions for beam-column connections were developed using data from cyclic load tests performed on beam-column connections constructed with concrete strengths of 6000 psi (41.4 MPa) or less. Results of twenty-six beam-column connection tests conducted in Japan and the US are used to evaluate current US provisions for use in design of exterior and interior beam-column connections constructed with concrete strengths exceeding 6000 psi.

The state-of-the-art on recent experimental research in Japan on beam-column joints with high-strength materials subjected to seismic loads is introduced. Previous experimental studies on beam-column joints in reinforced concrete frames for seismic resistance is outlined for the shear strength of beam-column joints and the deformation characteristics of subassemblages including beam-column joints. Analytical research using FEM microscopic models and macroscopic models have been done in order to deepen the understanding of the experimental results and to investigate the shear resisting mechanisms of the joints with high-strength materials. Recent analytical research on joints using high-strength materials is introduced.

The changes to the seismic design provisions of the revised New Zealand concrete design standard, NZS 3101:1995, for beam-column joints to allow for high strength concrete are outlined. The changes include bond equations for bars passing through beam-column joints to take into account concrete strength and other factors, and new shear equations for the design of horizontal and vertical shear reinforcement. The results of simulated seismic load tests conducted on one-way interior beam-column joints constructed of normal and high strength concrete with concrete compressive cylinder strengths ranging between 31 and 61 MPa are also briefly described. The changes to the revised standard and the tests indicate that there are advantages in using high strength concrete in moment resisting frames.