Comparison between plastic hinge length models in predicting ultimate deflection of HSC beams

Control of deflections is more important in the design of reinforced concrete beams. Best estimation of ultimate deflection is the key to better control of failure. The moment-area theorem is a simple method used to predict the deflections of reinforced concrete (RC) beams. This research uses the moment-area theorem to calculate yield and ultimate deflections of RC beams under mid-span and two-point loads. The study compares various models of plastic hinge length to predict ultimate deflection of RC beams. Experimental results from 33 RC beams with normal and high strength concrete were used to evaluate the performance of the models. The results showed that Panagiotakos and Fardis (2001) model provided the best predictions for RC beams under mid-span load and two-point loads with concrete strength over 70 MPa, with errors less than 20%. However, plastic hinge length can be neglected for RC beams under two-point loads with concrete strength less than 70 MPa, with errors less than 25%.