SHEAR DESIGN OF CONCRETE OFFSHORE STRUCTURES

Presents a strain compatibility procedure for the design of complex co ncrete structures subjected to combined membrane shear and transverse shear. The procedure, which is a three-dimensional generalization of t he modified compression field theory, accounts for triaxial (compressi ve and tensile) stresses in concrete between cracks and shear stresses on the crack surface. The method can be described as a three-dimensio nal variable angle truss model with a rational concrete contribution ( Vc), where the inclination of the truss is determined by strain compat ibility, and the concrete contribution is the shear that can be transm itted across diagonal cracks by aggregate interlock. Nine large-scale experiments in which elements of a concrete offshore structure wall we re subjected to combined membrane shear and transverse shear are prese nted. The equivalent beam approach, which is presently used to design concrete offshore structures, is not able to predict the experimental trend because it makes use of the traditional beam shear design equati ons, which are inaccurate when significant axial load is present, and also because it does not properly account for the orientation of the i n-plane reinforcement. The three-dimensional modified compression fiel d approach presented in this paper accurately predicts the influence o f membrane shear on transverse shear and, thus, is a more appropriate shear design method for complex concrete structures.