Experimental study on long-term behavior of prestressed steel I-beam–concrete composite beams

To investigate and predict the long-term time-dependent behavior, such as creep, shrinkage, and relaxation of PS strands, and prestress loss in prestressed steel–concrete composite beams, named Precom, full-scale tests were conducted and the collected data were compared with those obtained from the two proposed analytical models. The combined effective modulus method (EMM)-empirical model proposed with a flowchart considered the creep effect to determine the prestress loss. Conversely, the age-adjusted effective modulus method (AEMM) with CEB-FIP equation was developed to account for the concrete aging. The results indicated that the AEMM with CEB-FIP model predicts the long-term behavior of Precom effectively.