Modellazione dell'aderenza nei meccanismi di risposta di nodi trave-pilastro in c.a. in presenza di armature lisce

A fiber-beam element is modified for studying the effects of bond decay by using smooth steel bars on the behavior of R/C frames designed without antiseismic provisions. In order to describe the phenomenon, the efficiency of the curvilinear bars anchorage is estimated by a theoretical model, which is much easy to insert in the concentrated plastic hinges at the end of the fiber beam-column element, where the concrete-steel bars relative slippage is carried on. The finite element is then used to model an experimental cyclic test performed on a L beam-column joint of a non-antiseismic prototype construction, in order to test the theoretical model. The analyses show that the fiber beam element with ending pullout hinges provides results in good agreement with the experimental test, describing well both the bars slippage and the deformation of the whole structure.