National Transport Library Research Database

Utmattningsförutsägelse genom styrning av inspektionsintervaller (Fatige life prediction by damage tolerance using probalistic fracture mechanics - a feasability study)

Sponsors, duration, budget: Trafikverket ; 2014-08-01 -- 2015-12-31 Registration number:
  • Trafikverket 2014/11414
Subject(s): Abstract: Alternativ förutsägelse avseende kvarvarande livslängd med hänsyn till utmattning i stålkonstruktioner.Studien kommer att baseras på icke förstörande inspektionsmetoder som kalibreras mot praktisk syn i fält med nyttjande av tidigare gjorda inspektioner samt kompletterande inspektioner på järnvägsbron över Söderstörm i StockholmAbstract: This proposed research project focuses on one of the most frequent and important difficulties met by bridge managing authorities when assessing the remaining safe life of existing bridges. While conventional fatigue analysis suggest an already exhausted fatigue life, often with a damage factor several times larger than unity, inspection of the bridge structure shows no signs of fatigue damage. On the other hand, unanticipated fatigue cracking has been reported frequently for various bridge details due to secondary effects, some times already after few years in service. For both types of problems, conventional fatigue assessment methods based on “Safe-Life” philosophy fall short and cannot provide reliable basis for decision making for the bridge manager. The implication of this uncertainty might lead to unfounded decisions as to replace, strengthen or limit the functionality of the bridge, with substantial consequences on investment cost, mobility restrictions as well as environmental impact. This proposed project propose an alternative fatigue assessment philosophy that better cope with the difficulties and uncertainties met in the process of estimating the safe residual life of existing steel and composite bridges with respect to fatigue. The methodology follows the “Damage tolerance” principle proposed in Eurocode along with linear elastic fracture mechanics. In order to treat the large number of uncertainties generally associated with fatigue analysis, a probabilistic approach needs also to be adopted in the analysis.
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