Structural concrete: Cracked membrane model

After a review of limit analysis and compression field approaches and a discussion of a recently developed tension chord model, this paper presents a new model for cracked, orthogonally reinforced concrete panels subjected to in-plane stresses. The cracked membrane model combines the basic concepts of the modified compression held approach and the tension chord model. Crack spacings and tensile stresses between the cracks are determined from equilibrium conditions and bond shear stress-slip relationships, and the link to limit analysis is maintained since equilibrium conditions are formulated in terms of stresses at the cracks rather than average stresses between the cracks. Both a general numerical method and an approximate analytical solution are derived and corresponding results are compared with previous theoretical and experimental work. In addition, a computational procedure is proposed that makes it possible to treat cracks as fixed and interlocked rather than as rotating and stress free. implementation of this procedure is recommended for future research.