A new fiber element for refined nonlinear modeling of RC frame structures in seismic loading
Résumé
Accurate modeling of damping in nonlinear analysis of structures in seismic loading has become a challenging issue. As an alternative to commonly used global damping model such as Rayleigh's one, physical modeling of damping requires refined nonlinear models and advanced computational strategies because energy dissipation sources are numerous and occur at different scales. The purpose of this contribution is to present a new fiber element for refined nonlinear modeling of RC frame structures. Compared to existing fiber elements, innovations have been developed at local, fiber, and element levels. Local problem couples continuum lin- ear plasticity and damage and is solved without any iteration. Displacement field at fiber level is defined according to Euler-Bernoulli beam theory ; it is enhanced to allow modeling local- ization of the displacement and thus to provide a physical representation of the strain softening phase that occurs in quasi-brittle materials such as concrete. At the element level, the elementary stiffness matrix and internal forces vector are calculated by assembling the contribution of each fiber rather than the contribution of control sections. Simple examples are presented to illustrate some capabilities of this fiber element in quasi-static cyclic and monotonic loadings.