Fracture of beam-column connections with cope holes under large cyclic deformations

Abstract

A relationship between cord rotation (θp) and the number of deformation cycles to fracture initiation (N) is developed for steel moment frame welded beam-column connections with different cope hole sizes. The selected ductile fracture model is calibrated using material monotonic test results. It is then verified using small coupons considering different test regimes. The model with 45 mm cope hole radius was then calibrated for a welded connection tested under a uniform test regime. Then, further analyses of the configuration were conducted with cope hole radii ranging from 15 mm to 55 mm subjected to different test regimes. The number of cycles before fracture varied by up to 2.44 times for the range of cope hole sizes considered for the largest end displacement. Fracture initiated at the inside edge of the cope hole. The strength decreased with an increasing cope hole size, and equations to describe this were developed as a function of the remaining section plastic modulus.