Analysis of Stainless Steel-Concrete Composite Beams

Stainless steel is increasingly popular in construction projects owing to its corrosion-resistance, excellent mechanical and physical properties and its aesthetic appearance. The current paper is concerned with the use of these materials in steel-concrete composite beams, which is an entirely new application. Current design codes for steel-concrete composite beams are based on elastic-perfectly plastic steel material behaviour neglecting strain hardening. Whilst this is a reasonable assumption for carbon steel, stainless steel is a very ductile material which offers significant levels of strain hardening prior to failure. Therefore, current design provisions typically result in inaccurate and overly-conservative strength predictions when applied to stainless steel composite beams. The current study presents for the first time, an analytical solution for predicting the plastic bending capacity of stainless steel–concrete composite beams with either full or partial shear connection. This method is a development of the continuous strength method (CSM). Since the analytical analysis requires complex mathematical solution, a simplified analytical solution is also proposed, utilising some of the assumptions in Eurocode 4. There are no tests currently available in the literature for stainless steel-concrete composite beams. Therefore, a finite-element model is developed and validated against a number of experimental results for composite beams made from normal or high strength carbon steel. The validated numerical model is then used to investigate the accuracy of the proposed analytical solution. It is concluded that both the full and simplified analytical solutions are reliable and the simplified analytical method provides a straight forward design tool for practical engineers.