Fatigue life prediction of existing crane runway girders

In this study, fatigue life of crane runway girders of a steel mill structure was investigated. Load spectra were generated based on former crane operation records. Detailed finite element models of the crane runway girders were prepared using shell and beam elements. Quasi-static load tests were conducted with the help of overhead cranes that travelled with crawling speed. Strain data was collected by using transducers mounted on preselected locations of the crane runway girders. These data were then used to refine the finite element models. Numerical analyses by means of the calibrated finite element models were performed to evaluate the remaining fatigue life. It was found that due to lack of continuity of vertical stiffeners to upper flange, fatigue life of the crane girders is exceeded. To overcome this problem, fillet welding of the stiffeners to flanges is suggested and this modification is verified by carrying out necessary calculations for the updated detail.