Tensile behavior and net section resistance of Q960 high strength steel double shear bolted connections: Tests, simulations and design

This paper investigates the tensile behavior and net section resistance of Q960 high strength steel (HSS) double shear bolted connections through an integrated experimental and numerical study. The experimental program was conducted on a total of 21 Q960 HSS bolted connection specimens (e.g., 2-bolt connections, 4-bolt connections, 2-staggered-bolt connections and 3-bolt connections), and the test procedures, test setup as well as key results were reported in detail. Subsequently, finite element (FE) models of the Q960 HSS double shear bolted connections were established and validated based on the test results and the validated FE models were then used to conduct parametric studies. Based on the obtained test and numerical data, the effects of key geometric parameters and material ductility on the net section resistance and connection efficiency are extensively analyzed, from which, Q960 HSS bolted connections were concluded to still possess sufficient ductility to deform and achieve net section failure. Finally, the relevant European, American and Australian design rules were assessed for their applicability to Q960 HSS double shear bolted connections and then a new design method considering the influence of edge distance, transverse spacing, staggered pitch and transverse pitch on the net section resistance and connection efficiency of Q960 HSS bolted connections was proposed and assessed. The assessment results revealed that (i) the all three codes provide conservative failure load predictions for 2-bolted connections and 4-bolted connections, but lead to relatively accurate results for 2-staggered-bolted connections and 3-bolted connections, and (ii) the proposed design method provides the highest level of accuracy and consistency in predicting the net section resistance of Q960 HSS bolted connections compared to the three codified design rules.