Cyclic and monotonic performance of unstiffened extended end-plate connections having thin end-plates and large-bolts

This study presents the findings of comprehensive numerical and experimental programs on unstiffened extended end-plate connections (UEECs) having thin plates and large sized bolts. The main goal of the research program is to analyze the effects of variables influencing the capacity of these connections. Six specimens were subjected to cyclic and monotonic loading to achieve this goal. For the experimental part, the thickness of end-plate was chosen as the variable. The thickness of end-plates was selected to ensure failure modes governed by the bending capacity of end-plates. A comprehensive numerical study consisting of 156 finite element models where the parameters are I-section types, width and thickness of end-plate, edge distance, distance from flange to bolt row, bolt diameter and weld thickness was performed. The results showed that the connections with thin end-plates can perform high ductility and strength. Moreover, the design methods given by AISC 358-16 and EN1993-1-8 conservatively predict the plastic moment capacity of UEECs. According to numerical findings, the average ratios of actual to estimated plastic moment capacity by AISC 358-16 and EC3:1-8 are 2.77 and 3.13, respectively. These ratios alter to 3.70 and 3.93 for the experimental results. The yield line mechanism and the spacing be-tween the plastic hinges are to cause this underestimate. An expression for the observed yield line pattern is developed to estimate the plastic moment capacity more correctly. The actual to estimated plastic moment ca-pacity ratios according to proposed expressions are averagely 1.23 and 1.29 for the outcomes of the experimental and numerical study, respectively.