Maintenance Actions to Address Fatigue Cracking in Steel Bridge Structures: Proposed Guidelines and Commentary

Abstract

This document provides guidelines for the maintenance actions to address fatigue cracking and details at risk of constraint-induced fracture (CIF) in steel bridges. It is a synthesis of best practices from published literature, project reports, past and ongoing research projects, as well as input from industry professionals gathered through a web-based survey. Intended to be a very practical reference text, it is written with everyone in mind from a maintenance contractor to an asset manager and design engineer, providing detailed descriptions of the driving causes of fatigue cracking and CIF in steel bridges and accepted methods for repair or retrofit.

Strengthening of Steel Connections in a 92-Year-Old Railway Bridge Using Prestressed CFRP Rods: Multiaxial Fatigue Design Criterion

“…In addition, the presence of multiaxial stress state in the stringer-to-floor-beam angle connections increases the complexity of the problem. The reasons for overlooking the mean stress effect in codes could be the complexity of the calculations, and also the fact that prestressed retrofitting systems for the riveted structures have been mainly introduced in recent years and are not among the well-established repairing methods (Connor and Lloyd 2017).…”

“…However, many existing bridges do not satisfy the recommended formulations (Connor and Lloyd 2017). Therefore, the repairing techniques have been proposed by different researchers to solve the fatigue problem with existing bridges.…”

“…Traditional retrofitting techniques for retrofitting riveted metallic structures include the use of high-strength pre-tensioned bolts (Reemsnyder 1975;Baker and Kulak 1985;Al-Emrani 2002), welding additional elements, stop holes, repair of support conditions, etc. (Kuehn et al 2008;Dexter and Ocel 2013;Connor and Lloyd 2017). Additionally, in some cases, the connections were softened by removing some rivets (Bowman 2012).…”

Investigation of textured sensing skin for monitoring fatigue cracks on fillet welds

“…These cracks, if not detected and addressed in a timely manner, can have grave consequences, including brittle structural failures [2,3]. It is estimated that close to half of the nation's bridges have at least one load-induced fatigue crack reported on welds, gusset plates, riveted built-up members, or girders [4]. Of interest to this paper are cracks forming at welded connections.…”