Influence of Loading Rates on Single Shear-Bolted Lap Joints at Elevated Temperatures

Abstract

This research investigated the effect of loading rates or implicit creep on the strength and deformation capacities of single shear-bolted lap joints subjected to elevated temperatures. To address this issue, 16 bolted lap joints were tested under two different loading rates at temperatures ranging from 400°C to 700°C. The rate- and temperature-dependent retention factors for the bolt shear capacities were compared with those from previous studies in the literature. The effects of loading rate and temperature on the bolt pretension force also were examined. The results showed that all tested bolted lap joints failed in bolt shear. The results of the slow loading rate tests indicated a larger reduction in bolt shear capacities compared with the fast tests for temperatures greater than 400°C. That is, the effect of loading rate on the bolt shear capacity ranged from 18% to 36% difference for temperatures ranging from 450°C to 700°C, respectively. Finally, a strength reduction coefficient was introduced in the bolt shear capacity equation to account for the loading rate effect when designing bolted connections in fire.