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.

Flexural behavior of high strength concrete (HSC) beams was investigated based on the experimental work of a number of researchers. The effects of HSC on mechanical properties such as ,modulus of elasticity, tensile strength, limiting concrete compressive strain, and Poisson’s ratio were reviewed. The applicability of current ACI design guidelines and suggested modifications were compared with experimental data in terms of strength, ductility, and serviceability.

Considerations regarding bond and development of reinforcement in high strength concrete (HSC) are presented from a North American perspective. The information contained in this paper is a compilation of information from various sources and represents a survey of the basis for North American approaches to bond of normal and high strength concrete under monotonic and cyclic loading. The paper was presented in part at the Second US-Japan-New Zealand-Canada Multilateral Meeting on the performance of HSC held in Honolulu November 29-December 1,1994.

Synopsis: Recent research on confinement of high-strength concrete (HSC) is reviewed. The emphasis is placed on the effects of confinement parameters and related experimental research. A review of analytical models proposed for HSC is also presented. The results indicate that for similar strength and deformability, HSC requires higher confinement pressure than normal-strength concrete. The level of lateral pressure required can be provided by increasing the volumetric ratio and grade of continement reinforcement. The effkiency of pressure can be improved by reducing the spacing of lateral reinforcement in both the longitudinal and cross-sectional planes. When properly confined, HSC exhibits ductile stress-strain characteristics. The analytical models developed for normal-strength concrete cannot be used to describe stress-strain characteristics of HSC. A number of models have been proposed for HSC that produce good correlations with experimental data.

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.