Deformation mechanism of a novel pipe-roof composite slab: An experimental and theoretical investigation

• STS specimens exhibited good ductility and bending failure, with deformation curves following a half-sine wave under loading. • A bidirectional bending test was conducted to evaluate bending stiffness, load capacity, and deformation mechanisms of STS composite slabs. • A theoretical deformation prediction model for STS composite slabs was developed, accurately estimating bending stiffness. • Experimental and theoretical results agreed within 15% maximum error, providing design references for STS structures.