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The Canadian Highway Bridge Design Code (CHBDC) uses the concept of a target reliability index for evaluating the load carrying capacity of existing bridges. This index, which is based on risk to human life, relates to three aspects of uncertainties inherent in a bridge: (a) element behaviour, (b) system behavior, and (c) inspection level, where the inspection level currently refers to only manual inspections. Citing examples of tests on many instrumented bridges, the paper proposes an additional inspection level for inspections done with the help of electronic instruments and tests under controlled vehicle loads. The paper proposes simple additions to clauses of the CHBDC, for use when determining the optimum load carrying capacities of existing bridges where structural health monitoring information is available. Key words: bridge evaluation, inspection level, structural health monitoring, target reliability index. Le Code canadien sur le calcul des ponts routiers (CCCPR) utilise le concept d'un indice de fiabilite cible pour evaluer la capacite de charge des ponts existants. Cet indice, qui est fonde sur le risque pour la vie humaine, se rapporte a trois aspects des incertitudes inherentes a un pont : soit (i) le comportement des elements, (ii) le comportement du systeme et (iii) le niveau d'inspection, ou le niveau d'inspection ne fait actuellement reference qu'a des inspections manuelles. Citant des exemples d'essais sur de nombreux ponts instrumentes, dans ce document, on propose un niveau d'inspection supplementaire pour les inspections effectuees a l'aide d'instruments electroniques et d'essais sous des charges controlees de vehicules. Le document propose de simples ajouts aux clauses du CCCPR, qui serviront a determiner les capacites de charge optimales des ponts existants lorsque l'information sur la surveillance de l'etat des structures est disponible. [Traduit par la Redaction] Mots-cles: evaluation de pont, niveau d'inspection, surveillance de l'etat des structures, indice de fiabilite cible., 1. Introduction The Canadian Highway Bridge Design Code (CHBDC) uses the concept of a target reliability index for evaluating the load carrying capacity of existing bridges (Canadian Standards Association 2014a). [...]

In this paper, the performance of structures is modeled using lifetime functions. Specifically, the unavailability and redundancy are used as performance indicators, based on which optimum maintenance strategies are sought. Models that reflect the separate or combined effects of essential and preventive maintenance on the unavailability are presented. A novel optimization approach is proposed in which the problem is formulated to provide optimum maintenance strategies with either or both essential and preventive maintenance actions. Genetic algorithms are used to solve this problem. In this paper, multiple essential maintenance types and multiple preventive maintenance types are considered, and regular or irregular preventive maintenance time-intervals are considered. Furthermore, essential maintenance is treated as performance-based, i.e., essential maintenance is only applied when a performance threshold is reached, and an algorithm is proposed for conducting the optimization under uncertainty. Although applicable to any type of structure, the proposed approach is illustrated on a highway bridge example. DOI: 10.1061/(ASCE)ST.1943-541X.0000198 CE Database subject headings: Structural systems; Life cycles; Optimization; Maintenance; Deterioration. Author keywords: Structural systems; Lifetime functions; Redundancy; Availability; Lifetime performance; Maintenance; Multiobjective optimization; GA.

A method of deicing with carbon fiber heating wire (CFHW) buried inside concrete slab is presented in this paper, which avoids the negative effects on structure function and environment caused by traditional deicing salt. The rational interval range of CFHW buried inside concrete slab is determined by the temperature field of four heating CFHW and the minimum input powers for deicing under the conditions of different air temperatures and ice thicknesses are summarized by the laboratory experiments. Snow melts more quickly than the ice with same weight under the same input power condition by comparison the deicing processes in refrigerator. The field experiments of concrete slab performed satisfactorily: the snow on slab with the thickness of 10, 40, and 70 mm was melted in 0.75, 2.5, and 3.5 h, respectively, under an appropriate input power. It demonstrated that the electrothermal method of CFHW for bridge deck deicing is practicable. DOI: 10.1061/(ASCE)TE.1943-5436.0000117 CE Database subject headings: Bridge decks; Concrete slab; Ice. Author keywords: Bridge deck; Deicing; Carbon fiber heating wire; Concrete slab.

This paper reports on the monitoring and repair of a pilot field deployment of a glass fiber-reinforced polymer (GFRP) deck on a small steel girder bridge in the Washington State. Deck deflections were monitored periodically over a 10-month period and were found to increase significantly over that time. The GFRP deck is an adhesively bonded assembly of GFRP tubes and top and bottom plates. After 9 months of service, wearing surface cracking was observed, and upon closer inspection, the top GFRP plate was found to be delaminated from the tubes over a fairly large area. Deck deflections in the area of delamination were found to be considerably larger than those observed during previous monitoring in undamaged locations. A retrofit solution was employed where the top plate was reconnected to the tubes using screws coated with a two-part epoxy that mixed when they were driven. At the time of writing the retrofit was successful in reattaching the delaminated top plate. DOI: 10.1061/(ASCE)CF.1943-5509.0000102 CE Database subject headings: Composite structures; Bridges; Fiber reinforced polymer; Glass fibers; Bridge decks; Monitoring; Rehabilitation. Author keywords: Composite structures; Bridges; Fiber-reinforced polymers; Bridge decks; Field monitoring; Repair and maintenance.

Damage often causes changes in the dynamic characteristics of a structure such as frequencies and mode shapes. Vibration-based damage identification techniques utilize the changes in the dynamic characteristics of a structure to determine the location and extent of damage in the structure. Such techniques are applied in this study to the Crowchild Bridge, a steel-flee deck continuous bridge located in western Canada. While the numerical models of the bridge are correlated with the measured dynamic characteristics, computer simulation is used to study the identification of a number of different damage patterns, and the effects of measurement errors and incomplete mode shapes on the quality of results are evaluated. The effectiveness of some selected damage identification techniques is examined; the potential difficulties in identifying the damage are outlined: and areas of further research are suggested. A three-dimensional finite-element model and a simple two-dimensional girder model of the bridge have been constructed to study the usefulness of the selected damage identification methods. Another promising damage detection method proposed here is based on the application of neural networks that combines a vibration-based method. DOI: 10.1061/(ASCE)CF.1943-5509.0000071 CE Database subject headings: Vibration: Damage: Structural reliability: Monitoring; Neural networks: Continuous structures: Bridges; Canada. Author keywords: Vibration-based damage identification: Structural health monitoring: Steel-free deck: Artificial neural network.