United States–Japan Cooperative Earthquake Engineering Research Program on Composite and Hybrid Structures

Abstract

The United States‐Japan Cooperative Earthquake Research Program began in 1979 under the auspices of the UJNR panel on wind and seismic effects. The overall objective of the program was to improve seismic safety practices in both countries through cooperative studies to determine the relationship among fullscale, small-scale, and component tests, as well as related analytical and design implication studies. The first four phases of the program were Reinforced concrete ~RC! structures, steel structures, masonry structures, and precast concrete structures. Research on composite steel RC ~SRC! structures was identified as an important area of concern and recommended in the planning group report. Considering the importance of developing seismic design guidelines and code provisions for typical composite and hybrid structures that have been used in recent practice, and the need for developing new and innovative composite structural elements and hybrid systems using advanced new materials and devices, a 5 year research program on composite and hybrid structures was recommended as the fifth phase of the United States-Japan cooperative earthquake research program. The program contents were based on a number of technical meetings of the United States and Japan planning groups and on the outcome of a joint planning group workshop held in Berkeley, Calif. on September 10‐12, 1992 ~Goel and Yamanouchi 1992!. Because of the diverse and broad scope of the subject area, the research program was organized into the following four groups: concrete-filled tube~CFT! column systems; RC/SRC column systems ~RCS!; RC/SRC hybrid-wall systems ~HWS!; and new materials, elements, and systems ~compiled by Research for Innovation!. The first two systems are moment-resisting frames made of steel beams and either CFT or RC/SRC composite columns, whereas, the HWS systems utilize RC or composite shear walls and steel-beam and column frames. The research work on those three systems aimed at developing practical design guidelines as they represent typical composite and hybrid structural systems used in recent practice. The last group aimed at developing new and innovative composite structural elements and hybrid systems using advanced new materials and devices. A theme structure provided a common focus of the overall research program to facilitate cross-comparison between various system types, and to derive structural elements and subassemblages for detailed studies. The work carried out in the four groups listed previously is briefly described in the following sections.