On tension stiffening in cracked reinforced concrete slabs and shells considering geometric and physical nonlinearity

Abstract

The “tension stiffening effect” represents the capacity of the intact concrete between neighboring cracks to cany a limited amount of tensile forces. The reason for this effect is bond slip between the reinforcement and the neighboring concrete. In the present work, a theory of tension stiffening for thin reinforced concrete slabs and shells is presented which considers the influence of the angle between the reinforcement and the crack, the extent of crack propagation through the thickness of the shell and the propagation of secondary cracks between primary cracks. In addition to cracking and crushing of concrete, respectively, nonlinearity of concrete, yielding of reinforcement, geometric nonlinearity and the dependence of hydrostatic pressure on the displacements is accounted for. The investigation is performed with the help of the Finite Element Method. By comparison of analytically obtained ultimate loads and load-displacement diagrams, respectively, for one slab and one shell with experimentally obtained results, reported in the literature, the potential of the theory is demonstrated.