| Popis: |
In Reinforced Concrete (RC) structures, cracking is often a critical design parameter since engineering design codes limit the maximum crack opening to preserve the durability, tightness and aesthetics of RC buildings; robust and reliable crack opening computation methods are therefore necessary. For the case of large RC buildings (in particular for nuclear power plants), and specially for the case of cyclic (seismic) loadings, computational demanding finite element calculations are needed and so overall modeling is used. In this article, we propose to calculate the crack opening by means of a novel global (stress-resultant) nonlinear constitutive model for RC walls that incorporates crack opening as an internal variable. By means of an analytical averaging procedure and suitable physical hypotheses, four different local nonlinear phenomena are taken into account in the global model formulation [1]: (i) concrete cracking in two different crack directions and permitting both normal and tangential relative crack displacements; (ii) concrete stiffness reduction modeled by a scalar damage variable; (iii) steel-concrete slip and interface bond stresses, which are at the origin of the tension stiffening effect; and (iv) steel yielding localized at the cracks. The model is able to reproduce the behavior of RC plates submitted to in-plane and out-of-plane cyclic solicitations. Validation is provided by comparison with several experimental tests on RC structural elements, accounting for a large range of solicitations. Results show a good agreement both at global (force-displacement curves) and local (crack opening) levels. DOI 10.21012/FC9.105 Miquel Huguet et al. |
