Reinforced Concrete Columns: Insight on Energy-Based Assessment from Biaxial Tests with Different Load Paths

Results from a recently concluded experimental campaign on nonconforming reinforced concrete cantilever columns failing in both flexure and flexure-shear modes under five different load paths are used to discuss whether an energy-based failure criterion would be advantageous with respect to a deformationbased one. Based on the limited evidence of these 18 tests it appears that the relation between energy and damage, compared to that of drift ratio and damage, is influenced to a lesser extent by load path, but this only holds in some cases and cannot be generalized. In particular, the occurrence of any phenomenon that interrupts the stable energy dissipation mechanism through inelastic flexure leads to failure prior to the attainment of the energy threshold. This can occur in many practical situations indicating that it may not be feasible to use energy as a useful measure in the seismic assessment of existing frames.