Development of a New Design Approach for Composite Slabs

Composite slabs are simple and economical construction elements. However, the verifications that are required for their design (structural safety, serviceability) are long and complicated. Current design methods found in standards and guidelines rely on the results of costly and time-consuming large-scale laboratory tests. A new design approach for the prediction of composite slab behaviour is proposed. The new approach combines results from standard material tests and so-called small-scale tests with a simple calculation model, the New Simplified Method, to obtain the moment-curvature relationship at the critical cross-section of a composite slab. Unlike recently proposed methods, the calculation method described herein does not rely on computer dependent numerical simulations. Results obtained from using the new design approach have been verified through comparisons to large-scale tests. For greater acceptance and uniformity of the results obtained from the New Simplified Method, the development of a standardised small-scale laboratory test to measure the longitudinal shear versus slip behaviour at the steel-concrete interface is discussed.