Constitutive relationships of prestressed concrete membrane elements

Wall-type or shell-type prestressed concrete structures, such as shear walls, deep beams, box bridges, nuclear containment vessels, and offshore structures can be visualized as assemblies of membrane elements. Their behavior can be predicted if the behavior of the membrane elements is thoroughly understood. Since prestressed concrete structures are now widely used, this research investigates the behavior of prestressed concrete elements subjected to shear action.;Ten prestressed concrete panels were tested using the Universal Panel Tester at the University of Houston. Based on these test results, the Softened Membrane Model (SMM), which is applicable only to reinforced concrete, is extended for application to prestressed concrete. This generalized SMM is applicable to both non-prestressed and prestressed concrete, of any ratio of longitudinal steel to transverse steel, and of any orientation of steel reinforcement with respect to the principal stresses. It could also be applicable to high strength concrete of up to 100 MPa.;The new generalized SMM includes the following three new constitutive laws: (1) A generalized constitutive law of concrete in tension which includes the decompression stage. (2) A new prestress factor Wp proposed for incorporation into the softening coefficient of the constitutive laws of concrete in compression. (3) A generalized smeared (average) stress-strain relationships of prestressing strands embedded in concrete.