Corrugated fold roof deck plates are used for roofs in steel buildings and are cost effective without concrete slab. In addition to their strength and stiffness against loads in out-of-plane vertical directions, they have certain capability to resist loads in the in-plane horizontal directions providing the diaphragms of roofs. The roof deck plates are typically connected to the beams with puddle welding. They can rapture under excessive shear force experiencing large inelastic strain around the connections. The material properties of the plates are firstly investigated including their large strain region. Simplified material properties for FEM simulation is secondly proposed and are varied with the test data of the connections with puddle welding.
