Flexural behavior of lean duplex stainless steel girders with slender unstiffened webs

The behavior of lean duplex stainless steel plate girders (LDIPGs) with slender unstiffened webs is studied in this paper. Firstly, shell finite element models are validated using experimental test results available in the literature. Secondly, these models are used to investigate the behavior of LDIPGs subjected to uniform bending. Parametric studies for the LDIPGs are carefully designed based on three parameters: the radius of gyration of the compression flange (rT ), the section modulus (Sx ), and the unbraced length (Lb ). The results showed that LDIPGs with higher rT but similar Sx values can attain higher flexural strengths compared to their yield strengths because of the higher torsional rigidity of the flanges and stockier webs. On the other hand, by increasing the Sx value of the girder but keeping fixed the rT values, the moment carried by the girder is found relatively to decrease with the simultaneous increase in the amount of steel. Finally, the numerical results are compared with predictions given by design standards. It is found that the EC3 provides conservative bending predictions. Accordingly, the imperfection factor associated to buckling curve (c) is recommended to be used in the scope of the design method provided by EN 1993-1-4.