TIME-DEPENDENT BEHAVIOR OF MULTI-SPAN CONTINUOUS STEEL-RAC COMPOSITE SLABS CONSIDERING THE LOADING DISTRIBUTION EFFECTS

To quantify the impact of recycled coarse aggregate (RCA) incorporation on the time-dependent behavior of multi-span continuous steel-RAC composite slabs, nonlinear thermal-mechanical finite element (FE) models were proposed based on ABAQUS, considering the combined effects of non-uniform shrinkage, non-uniform creep and concrete cracking. The proposed models were benchmarked against the long-term data from 18 full-scale composite slabs. The feasibility of current design procedures was also evaluated. Using the verified FE models, the influence of the RCA replacement ratio (r) on the time-dependent distributions was quantified. The results show that by specifying the temperature variation to simulate the non-uniform shrinkage and creep, the proposed FE models could well predict the time-dependent behavior of steel-RAC composite slabs based on the age-adjusted effective modulus method. The maximum error between the measured and calculated mid-span deflections was 20.3%. The time-dependent behavior of the composite slabs was remarkably influenced by the RAC incorporation. The influence magnitudes were similar for the composite slabs under different loading distributions. Under uniformly distributed loading, 22.1% and 45.0% increments in the mid-span deflection and 5.3% and 10.8% increments in the hogging moment were obtained for r ratios of 50% and 100%, respectively. The influence of the loading distribution on the mid-span deflection and hogging moment was within 10%.