Design Methods for Static Performance of Steel-Bars Truss Slabs Considering Effects of Profiled Steel Sheets

To investigate the effects of profiled steel sheets on the flexural capacity, short-term and long-term stiffness of steel-bars truss slabs, typical design methods for reinforced concrete slabs and composite steel-concrete slabs were first summarised and evaluated, and benchmarked against the test results reported by the authors and other researchers. Design procedures were then proposed for steel-bars truss slabs considering the influence of profiled steel sheets. The results indicated that the profiled steel sheets in steel-bars truss slabs could reach their yield strength under ultimate limit state, and therefore an increase of 47.0%-60.3% in the flexural capacity was observed for steel-bars truss slabs when compared to slab samples without profiled steel sheets; the contribution of profiled steel sheets to the short-term stiffness was significant, and the increase magnitudes were 112.1%-180.0%, despite the strains of profiled steel sheets under the normal service load were smaller than expected; the sealing effect of profiled steel sheets resulted in uneven distribution of shrinkage deformation of concrete along the height of cross section, and an additional 119.7% deflection could be obtained accordingly. Span-to-depth ratio and ambient relative humidity were the key factors that influenced the shrinkage performance of steel-bars truss slabs, and the proposed design procedures accounting for non-uniform shrinkage distributions showed good accuracy with the test results, with the ratio of 0.951-0.979 and the correlation coefficient R² of 0.657-0.873.