Integrity analysis on existing crane runway girders with defects using constraint-based R6 criterion

In order to resolve the safety problem of the existing crane runway girders (CRGs) with defects, the constraint-based R6 criterion is proposed to assess their structural integrity. The existing steel CRGs with defects at the weld joint between the upper flange and web plate, are characterized to three-dimensional finite element models with a semi-ellipse surface crack. The R6 criterion has been modified by considering the constraint effect which is represented by T-stress. The analysis results illustrate that working condition of the cracked CRGs leads to high constraint level along the crack front. The crack aspect ratio (a/c) and runway eccentricity (e) have significant influence on the integrity of the cracked CRGs. The integrity assessment results based on modified constraint-based R6 failure criterion enable to more effectively protect the cracked CRGs from brittle fracture failure. © 2020 Tech Science Press. All rights reserved.