Development of Advanced Constitutive Models for Plain and Reinforced Concrete.

Abstract : The objective of the research is to develop a new and advanced approach to modeling the constitutive behavior of reinforced concrete that provides substantial improvement over existing approaches, especially in the nonlinear response regime. To accomplish this, the research has been partitioned into two major tasks, which are being pursued concurrently. One task consists of formulating a procedure (mixture theory) for analytically mixing reinforcing steel and plain concrete, so that the interaction between the two is properly modeled. The other task consists of developing a model of plain concrete, which accurately portrays its nonlinear, multiaxial behavior and is also computationally feasible for use in conjunction with the mixture theory. The mixture theory is designed to synthesize the global constitutive properties of reinforced concrete from the properties of plain concrete, steel, interfaces and reinforced geometry. The progress made during the first year's effort toward achieving these objectives is described.