Shear strength model for steel shape-reinforced concrete girders considering compatible steel-concrete interaction

Steel shape-reinforced concrete (SRC), also known as concrete-encased steel, offers numerous benefits compared with conventional reinforced concrete (RC) or bare steel due to its combination of RC and structural steel sections; therefore, SRC members find extensive use as transfer elements or girders in engineering applications. When evaluating SRC girders' shear resistance, the direct strength superposition of RC and structural steel is basically used in most design codes, ignoring the steel-concrete interaction under shear, which has proven unreasonable because of the brittle shear behavior of RC. This paper suggests a novel method for assessing SRC girders' shear resistance mechanism. The proposed method involves modeling the RC portion by a hybrid trussarch analogy; in addition, based on the strain compatibility condition, the steel profile's contribution is determined by applying the yielding criterion. Finally, the rationality of the proposed model is validated through a comprehensive comparison with previously published models and a set of 45 experimental test data samples available in the existing literature, and the results show that the proposed model can reasonably predict the maximum load-carrying capacity of SRC girders and is superior to existing shear strength models and code-based equations.