Analytical model of ductile reinforced concrete frames allowing for elongation of plastic hinges
Elongation in reinforced concrete members can have detrimental effect on the seismic performance of reinforced concrete structures. For reliable assessment of seismic performance, analytical models should take into account this elongation phenomenon. In this paper, an analytical model of plastic hinges has been developed and implemented into an analysis package. This model consists of a layer of horizontal concrete and steel springs to simulate the flexural behavior, as well as diagonal springs to represent the diagonal compression struts and to resist the shear force. The model is verified against experimental results of beams and frame subassembly tests found in literature. Comparisons of the analytical predictions and the experimental results show that this model can make significant advancement in predicting elongation in beam plastic hinges. It can be used to assess the effect of beam elongation on the seismic performance of reinforced concrete frame structures.