Fatigue crack repair by TIG-remelting
Paper i proceeding, 2021

Fatigue is one of the most detrimental problems that often limit the service life of steel bridges. Because of that, different post-weld treatment methods have been studied to extend the fatigue life and repair any existing cracks resulted from the traffic loading. The aim of this paper is to study the fatigue life extension of cracked structures by means of Tungsten Inert Gas (TIG) remelting. Fatigue tests were conducted at a stress ratio of 0.29 on a transverse attachment of 16 mm, thick-walled specimens. The specimens were instrumented with multiple strain gauges along the weld to detect the strain drop caused by crack growth. The specimens were pre-fatigued until a crack of around 1 mm- deep was obtained at the weld toe. After crack detection, the weld toes were treated by TIG-remelting to remove any existing cracks and to reduce the local stress concentration. The weld parameters were controlled so that the fusion depth was always larger than the crack depth. A substantial fatigue life extension could be achieved and the testing led to ran-out after 10 million cycles, which was attributed to the improvement in geometry and residual stress. Weld toe radius was measured before and after treatment by a laser scanner. Hole drilling was used to measure the residual stresses in as-welded state and after TIG-remelting. In this paper, a fatigue damage model is also presented. It is shown that the model gives a good prediction of the effect of TIG-treatment in repairing fatigue loaded welded details.

TIG remelting, Fatigue crack, crack repair


Hassan al-Karawi

Chalmers, Arkitektur och samhällsbyggnadsteknik, Konstruktionsteknik

Asma Manai

Chalmers, Arkitektur och samhällsbyggnadsteknik, Konstruktionsteknik

Mohammad al-Emrani

Chalmers, Arkitektur och samhällsbyggnadsteknik, Konstruktionsteknik

R. U.Franz von Bock und Polach

Technische Universität Hamburg-Harburg (TUHH)

Nils Friedrich

Technische Universität Hamburg-Harburg (TUHH)

Joakim Hedegård

Swerim AB

Bridge Maintenance, Safety, Management, Life-Cycle Sustainability and Innovations Proceedings of the Tenth International Conference on Bridge Maintenance, Safety and Management (IABMAS 2020), June 28-July 2, 2020, Sapporo, Japan

978-036723278-8 (ISBN)

10th International Conference on Bridge Maintenance, Safety and Management (IABMAS 2020)
Sapporo, Japan,

LifeExt - Livslängdsförlängning för befintliga stålbroar

VINNOVA (2017-02670), 2017-06-08 -- 2019-12-31.

Trafikverket (TRV 2018/27547), 2018-05-15 -- 2020-11-30.


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