Inelastic Model for Cyclic Biaxial Loading of Reinforced Concrete

Abstract

Reinforced concrete is a major medium of construction throughout the world. While in service, reinforced concrete structures are subjected to many cycles of load. In the case of structures subjected to seismic loading, the cycles may be of large magnitude. The material within these structures is in a triaxial state of stress. In contrast, the procedures used in the design of reinforced concrete members are based primarily on short-term monotonic load tests, and the material properties used in design are obtained from uniaxial strength tests (4).

Experimental investigations (1,16,20,22,26,34,35), not yet incorporated into design procedures, have shown that the behavior of concrete and steel varies considerably from that demonstrated in simple strength tests when the materials are subjected to cycles of load, and in the case of plain concrete, to combinations of biaxial stress.

These findings, combined with the ever increasing complexity of reinforced concrete structures, make a strong case for continued research. The need for safe, economical structures can be satisfied to the fullest only when the behavior of the structures is adequately understood. One tool in research is the analytical model which provides a prediction of the behavior of reinforced concrete under varying load conditions. This report presents an inelastic model for the cyclic, biaxial loading of reinforced concrete.