experimental study on the long-term behaviour of rbpc t-beams

This study compares the mechanical properties of the retard-bonded and conventionally bonded prestressed concrete (rbpc and bpc, respectively) under uniform loads. results show that the prestressed strands and concrete of the rbpc t-beams are firmly bonded with harden of retard-bonded materials, thereby exhibiting the same mechanical properties as that of the bpc beams. the growth rate of the long-term deflections of the rbpc t-beam is slightly lower than that of the bpc t-beam. given the effect of concrete shrinkage, creep and time variation of prestress loss, the regular patterns of deflection growth of the rbpc t-beam mid-spans are analysed based on the age-adjusted effective modulus method, method of equivalent prestress load and calculation model of prestress loss. accordingly, the long-term deflection development curves of the rbpc t-beam mid-spans under self-weight, prestressing force and external loads are obtained. calculation results are in good agreement with the test results. this method has immense applicability for the computation of the rbpc t-beams, and can be used to estimate the long-term deflection growth of regular patterns of the rbpc components.