Influence of the Shear-Bending Interaction on the Global Capacity of Reinforced Concrete Frames

In many seismic countries in the world (e.g. Europe, Northern USA, Japan, Turkey, etc.), the assessment of existing structures is a priority, since the majority of the building heritage was designed according to out-of-date or even non-seismic codes. The uncertainties about the nonlinear behaviour of the structures are, therefore, important and the nonlinear response should be treated directly, with a correspondingly strong increase in complexity of the assessment procedure. The assessment of regular reinforced concrete frame buildings has been performed, according to the Italian Seismic Code, Eurocode 8 and the CNR DT-212 guideline. A lumped plasticity model has been used with the aim of quantifying the differences between a fixed and a continuously updated shear span and between the use of inelastic springs located at the member ends or continuously along the beam elements, and with the purpose of considering the influence of axial-bending-shear interaction on the global capacity of the buildings.