Statistical modeling and safety analysis for developing design resistance of deconstructable HSFGB shear connectors in composite beam

In recent years, the high-strength friction-grip bolt (HSFGB) shear connectors in steel-concrete composite beams as deconstructable connectors are of great research interest since they are aligned with sustainable construction. However, the design strength equation for this type of connector has not yet been provided by the design codes such as AISC and Eurocode 4. In this paper, with regard to the reliability aspect, the design strength equation of HSFGB shear connectors is investigated which is projected into a partial safety factor according to Eurocode 4. Accordingly, the three-dimension finite element (FE) push-out model of the composite connection is developed and verified via experimental results to predict the load-slip behavior and failure modes in this type of bolted shear connector. Then One-Factor-at-a-Time (OFAT) method as a sensitivity analysis and Plackett-Burman (PB) design method as a screening analysis are utilized to identify the effective factors of the ultimate strength of HSFGB connectors. Finally, based on a complete database of all existing experimental findings, the results obtained from 55 three-dimension finite element models conducted in this paper, and appropriate statistical analysis, a high-precision equation for predicting ultimate strength is provided. Then the value of the partial safety factor is determined through a reliability study in accordance with EN1990, which provides an acceptable level of safety for the proposed design equation based on Eurocodes. Reliability analysis found that a partial factor of 1.52 was justified for the design strength of HSFGB connectors, which differed from the partial factor of 1.25 stated in the EC for welded stud shear connectors.