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Bridge infrastructure assets should be planned, designed, constructed, and operated to account for the physical processes that may occur over their service lives. In ice-affected rivers, this includes the interaction of bridge infrastructure with river ice. Advancements in river-ice science and modelling of ice processes in ice-covered rivers have enhanced the abilities of civil/hydrotechnical engineers to plan, design, and construct bridges in and along rivers with seasonal ice covers. In this paper, an overview is presented of ice-related considerations with respect to bridges. The bottom-chord elevation of the bridge superstructure with respect to water and ice levels, pier design to withstand ice forces, the waterway opening for ice passage, ice-induced scour, and research needs are discussed. However, as outlined in the paper, research on ice loads and passage at bridge sites and on hydroclimatic and ice conditions that led to bridge damage and failure remains needed. [ABSTRACT FROM AUTHOR]

The majority of civil infrastructure projects involve activities that are repeated across a number of linear units (e.g., highway sections) or scattered units (e.g., multi-bridge rehabilitations). For these projects, Critical Path Method (CPM)/line-of-balance (LOB) repetitive scheduling combines the benefits of CPM and LOB analyses to maintain work continuity across units, yet assumes simple sequential unit order and results in schedule delays for practical projects with non-identical units, constrained resources, and (or) strict deadlines. To improve CPM/LOB scheduling, this paper introduces powerful and easy-to-use enhancements, including (1) designed interruptions to reduce time gaps; (2) efficient resource-constrained first-come first-serve crew assignment; (3) crew adjustment loop to meet deadlines; and (4) representation of flexible unit sequence. These simplified enhancements computationally produce schedules that respect deadlines, individual resource limits, and desired sequence among units. Example projects are then presented to prove that the proposed enhancements offer flexible scheduling features that can meet the strict constraints of infrastructure projects. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Military vehicles are sometimes required to transit bridges owned and operated by civilian bridge authorities. Using available data regarding the gross vehicle weight and associated axle loads of military traffic, live load factors, calibrated to the Canadian Highway Bridge Design Code, are proposed for bridge design and evaluation. This paper recommends live load factors for three categories of military vehicles: (i) wheeled-transport vehicles; (ii) wheeled-fighting vehicles; and (iii) tracked-fighting vehicles. The values are derived for interior girders of simply supported slab-on-girder bridges subjected to a single lane of traffic loading and are believed to be generally applicable for other structural elements and bridge types. Inherent differences between fighting vehicles, which are heavily armoured, and transport vehicles, which although armoured have high payloads, suggest that highway bridges should be evaluated separately for military fighting vehicles and military transport vehicles using distinct live load factors. [ABSTRACT FROM AUTHOR]

This paper presents an experimental program to justify the barrier design at the barrier-deck junction when compared to the factored applied transverse vehicular loading specified in the Canadian Highway Bridge Design Code (CHBDC). Compared to the dimensioning and the glass fibre reinforced polymer (GFRP) bar detailing of a recently crash-tested GFRP-reinforced barrier, the adopted barrier configurations in this paper were similar to those specified by Ministry of Transportation of Québec (MTQ) for TL-5 barrier except that the base of the barrier was 40 mm narrower and the deck slab is of 200 mm thickness, leading to reduction in the GFRP embedment depth into the deck slab. Four full-scale TL-5 barrier specimens were tested to collapse. Correlation between the experimental findings and the factored applied moments from CHBDC equivalent vehicle impact forces resulting from the finite-element modelling of the barrier-deck system was conducted followed by recommendations for use of the proposed design in highway bridges in Québec. [ABSTRACT FROM AUTHOR]

This paper describes the development of a unique rolling load simulator (ROLLS) for testing bridge superstructure with a footprint up to 4 m ×17 m, and its first application to test a full-scale 1220 mm ×900 mm ×16000 mm B900 prestressed concrete box girder. This facility at Queen's University in Kingston, Ontario, is the first of its kind in Canada. ROLLS can apply cyclic loading in a controlled laboratory environment, under realistic highway scale 'rolling wheel loads', in lieu of the conventional 'pulsating stationary loads'. It has two half-axles of a large tandem, each comprising a dual 1140 mm diameter air-inflated tires spaced at either 1.2 or 2.4 m. Each half-axle can apply up to 125 kN, representing the heaviest half-axle load of the CL-625 design truck of the Canadian Highway Bridge Design Code (CHBDC). The maximum travel range and speed are 14.9 m and 6 m/s, respectively. A case study involving analysis of a bridge with eight adjacent B900 box girders of 27.6 m span was carried out prior to experimentally testing one of the girders using ROLLS. Load distribution analyses were conducted using both (i) a finite element model of the full bridge under various CL-625 truck loading configurations and (ii) the CHBDC load distribution method, and both agreed well. Scaling analysis of the girder load share was then conducted to account for shortening it to 16 m to fit in the laboratory, resulting in two-115 kN ROLLS design loads, 1.2 m apart. Multiple passes were conducted at various loads of 40%–100% of the design load, at speeds of 1–5 m/s to examine the machine and girder behaviours. It was found that the applied load fluctuates by less than 10% of full capacity and a 0.13 s/cycle time lag occurs. The measured girder deflection and elastic strains were 11%–20% lower than predicted theoretically. With the two half-axles assembly spaced at 1.2 m, the apparatus has the ability to complete three million cycles in approximately 4.5 months if ran continuously at 5 m/s. [ABSTRACT FROM AUTHOR]

In this paper, a novel pier scour indicator is introduced, which uses the ratio between mode shape amplitudes identified at two points on an integral bridge structure to monitor the progression of scour erosion. The mode shape ratio (MSR) is investigated as an additional parameter to complement the use of changes in natural frequency as a scour indicator. The approach is demonstrated using numerical modelling and the MSR is extracted from acceleration signals arising in the structure due to modelled ambient and vehicle-induced vibrations. The MSR shows higher sensitivity to scour erosion than the more commonly researched natural frequency. Furthermore, the variation in MSR under temperature fluctuations is inversely related to that of frequency, in that it increases with increasing temperature whereas frequency decreases with increasing temperature. This inverse relationship potentially enables the separation of the scour effect from the temperature influence on the dynamics of the system. [ABSTRACT FROM AUTHOR]

Three highway bridges in the Canadian province of Manitoba are being monitored continuously not only for their long-term performance but also for bridge weighing-in-motion (BWIM). Data collected for the BWIM study has led to some observations that have far-reaching consequences about the design and evaluation loads for highway bridges. This paper presents the well-known concept of equivalent base length, Bm, as a useful tool for comparing trucks with different axle weight and spacing configurations as they influence load effects in all bridges. It is discussed that the statistics of gross vehicle weights (GVWs), W, collected over a one-month period is not significantly different from that for the GVW data collected over a longer period. A rational method concludes that the value of W for the CL-W Truck, the design live load specified by the Canadian Highway Bridge Design Code, is 555 kN for Manitoba. The observed truck data in Manitoba presented on the W–Bm space is found to be similar to that collected in the Canadian province of Ontario more than four decades ago. It was also found that the multi-presence factors, accounting for the presence of side-by-side trucks in two-lane bridges, specified in North American bridge design and evaluation codes are somewhat conservative. [ABSTRACT FROM AUTHOR]

Fusing collected inspection data provides comprehensive and relatively more accurate diagnostics of defects and accordingly more accurate condition assessment of structures. This paper presents a new two-tier method that utilized data fusion methods for condition assessment of reinforced concrete bridge decks. The method utilizes pixel and feature levels fusion of data collected from multiple nondestructive evaluation (NDE) methods such as ground penetrating radar, impact echo, half-cell potential, and electrical resistivity. Data and measurements of NDE methods are extracted from the Iowa Highway research board project 2011 report for three case studies. It is observed from the three cases that each level of data fusion has its unique advantage. The power of pixel level fusion lies in its ability to provide an overview of bridge deck deterioration in one map as it appears in the fused image. On the other hand, feature fusion works better when only specific types of defects such as corrosion, delamination, and deterioration captured from inspection carried out by each of technologies referred to above. The proposed method is tested against filed inspection methods and core sample results described in the three case studies. The main findings of this research recommend utilizing data fusion in two levels as a new method to facilitate and enhance the confidence and capabilities of inspectors in interpretation of the NDE test results. [ABSTRACT FROM AUTHOR]

This paper presents key data and relevant analyses assessing low temperature exposure for design and evaluation of elastomeric bridge bearings and isolators in Canada. A large database of temperature records is processed to investigate the potential for instantaneous thermal stiffening and crystallization. The results mainly show that: ( i) temperature conditions at some locations lead to a significant potential for instantaneous stiffening in terms of intensity and frequency; ( ii) in warmer locations, thermal stiffening is highly improbable; ( iii) the number of consecutive days below a given low temperature is very variable geographically; and ( iv) the crystallization testing criteria prescribed in CSA S6-14 can be too conservative. The results are also illustrated using contour maps. Important differences in temperature variation trends between eastern and western Canada are highlighted. The proposed methodology and obtained results constitute efficient tools to determine site-specific temperature conditions for enhanced performance-based design and evaluation of bridges in Canada. [ABSTRACT FROM AUTHOR]

This paper proposes an updated vehicle-tire contact force model to simulate vehicle-bridge interaction, considering the tire contact area and the thickness of the bridge wearing surface. In contrast to the traditional methods of using a single-point tire contact force with a moving average filter, the proposed model uses multiple-point contact forces to account for the tire contact area. Results show that both the longitudinal and transverse distribution of tire contact force have a significant effect. [ABSTRACT FROM AUTHOR]

This paper presents the results and findings from several sets of experimental data on afflux around bridge waterways in overbank flow condition. The paper also investigates the accuracy, capability, and suitability of one-dimensional hydraulic river modelling software (HEC-RAS and ISIS) to model flow through bridge structure. To eliminate a scaling effect between the laboratory-scale experiments and model techniques, all experimental results were scaled up using an undistorted-scale model in which both the vertical and horizontal scale ratio was 100. A total of six methods of predicting afflux, the energy method, the momentum method, the water surface profile (WSPRO) method, Yarnell's method (in HEC-RAS), the U.S. Bureau of Public Roads (USBPR) method, and the arch bridge method (in ISIS) were compared with scaled up experimental results. The results for ISIS are significantly different from the measured data and the output from HEC-RAS. The energy method and the momentum method in HEC-RAS are the most accurate methods to compute the afflux around the bridge waterways. [ABSTRACT FROM AUTHOR]

This paper examines two new types of bridges, namely under-deck cable-stayed bridges and combined cable-stayed bridges, for prestressed concrete road bridges with single-spans of medium length. Both bridge types offer many advantages over conventional schemes in several aspects, such as structural efficiency, enhanced construction possibilities, and both economic and aesthetical considerations. They are very slender structural types with a very high structural efficiency, for which the materials used in the deck are reduced to one third of that in conventional bridges without stay cables. In this paper, the most important aspects of the structural behaviour of these bridge types are set out through the description of a careful selection from an extensive collection of bridges designed and analysed by the authors in a previous research project. In addition, a detailed set of design criteria for these bridge types is presented, based on the results of the extensive parametric study undertaken in the aforementioned research project. Cet article étudie deux nouveaux types de ponts, les ponts à haubans sous pont et les ponts à haubans combinés, pour les ponts autoroutiers en béton précontraint à portée unique de longueur moyenne. Les deux types de ponts présentent plusieurs avantages par rapport aux méthodes conventionnelles, soit l’efficacité de la structure, de meilleures possibilités de construction et des aspects économiques et esthétiques. Ce sont des types de structures très effilées avec une efficacité de structure très élevée, dans lesquels les matériaux utilisés dans le tablier sont réduits au tiers de ceux des ponts conventionnels sans haubans. Dans cet article, les plus importants aspects du comportement structural de ces types de ponts sont énoncés dans la description d’une sélection soignée d’une série complète de ponts conçus et analysés par les auteurs dans le cadre d’un projet de recherche antérieur. De plus, un ensemble détaillé des critères de conception de ces types de ponts est présenté; il est basé sur les résultats d’une vaste étude paramétrique entreprise lors du projet de recherche mentionné précédemment. [ABSTRACT FROM AUTHOR]

This paper deals with the application of under-deck cable-staying systems and combined cable-staying systems to prestressed concrete road bridges with multiple spans of medium length. Schemes using under-deck cable-staying systems are not suitable for continuous bridges, as they are not efficient under traffic live load and only allow for the compensation of permanent load. However, combined cable-staying systems are very efficient for continuous bridges and enable the design of very slender decks (1/100th of span) where the amount of materials used is halved in comparison with conventional schemes without stay cables. In this paper, the substantial advantages provided by combined cable-staying systems for continuous bridges (such as high structural efficiency, varied construction possibilities, both economic and aesthetical benefits, and landscape integration) are set out. Finally, design criteria are included. Cet article étudie l’application des systèmes à haubans sous pont et des systèmes à haubans combinés pour des ponts autoroutiers en béton précontraint de plusieurs portées de longueur moyenne. Les systèmes utilisant les systèmes à haubans sous pont ne conviennent pas aux ponts à travées continues puisqu’ils ne sont pas efficaces sous des charges de roulage dynamiques et ne permettent que la compensation de la charge permanente. Toutefois, les systèmes à haubanage combiné sont très efficaces pour les ponts à travées continues et permettent la conception de tabliers très effilés (1/100 de la portée) dans lesquels la quantité de matériaux utilisés dans le tablier est réduite de moitié par rapport à ceux des ponts conventionnels sans haubans. Dans cet article, les plus importants avantages des systèmes à haubanage combiné pour les ponts à travées continues sont énoncés : la grande efficacité de la structure, de meilleures possibilités de construction, les aspects économiques et esthétiques ainsi que l’intégration au paysage). Les critères de conception sont également inclus. [ABSTRACT FROM AUTHOR]

Bridges are vital components of the transportation network and if they are damaged or destroyed during a flood, they isolate communities and limit movement of supplies and emergency services. Evaluating their constructional stability and structural response after a flood event is critical for bridge safety. Bridge studies are usually designed with an assumption of an open channel flow condition, but the flow regime can switch to pressure flow if the downstream edge of a bridge deck is partially or totally submerged during a large flood. The main goal of this paper is to study the pressurized flow scour under a bridge deck and downstream deposition that results from eroded sediment material governed by both steady and unsteady clear-water flow conditions. Experimental conditions used in this study involve clear-water scour of a sand bed of given median sediment size d50 = 0.90 mm and sediment uniformity σg = 1.29, an approach flow characterized by a flow depth and velocity, a rectangular-shaped bridge deck, and a stepwise flood hydrograph defined by its time to peak and peak discharge. Different flow conditions were considered in confined flow under the bridge deck. Relationship between pressure-flow scour and flow conditions is presented and discussed under the obtained experimental data. Additionally, effects of single-peaked stepwise flow hydrographs (unsteady flow conditions) on bridge pier scour depth are investigated under clear-water pressure-flow conditions, whereas previous researches mainly focused on the equilibrium pressure scour under steady flow conditions. [ABSTRACT FROM AUTHOR]

Recent research efforts have focused on the development of performance based seismic design methodologies for structures. However, the seismic design rules prescribed in the current Canadian Highway Bridge Design Code (CHBDC) is based largely on force based design principles. Although a set of performance requirements (performance objectives) for different return period earthquake events have been specified, there is no explicit requirement in the CHBDC to check the attainment of such performance objectives for the designed bridges. Also, no engineering parameters have been assigned to the specified performance objectives. This paper correlates seismic performance objectives (both qualitative and quantitative) with engineering parameters, based on the data collected from published experimental investigations and field investigation reports of recent earthquakes. A simple method has been developed and validated with experimental results for assessing the performance of bridges designed according to CHBDC. It has been found that the design rules prescribed in CHBDC do not guarantee that specified multiple seismic performance objectives can be achieved. An implicit seismic design rule in the form of performance response modification factor has been outlined for the performance based seismic design of bridges. [ABSTRACT FROM AUTHOR]

This paper provides a summary of the damage to bridges in the Mw 8.8 Chile earthquake of 27 February 2010. Lessons from the different types of structural damage observed on concrete and steel bridges are discussed. The important roles played by soil liquefaction, settlement and embankment failures are highlighted. Aspects such as shear failure of steel piles, shear failure of concrete substructure elements, failures and severe buckling of steel braces, failures of shear keys and restrainers at supports, and damage to girders due to lack of diaphragms are described. Many examples of loss of superstructure support are presented. Skew supports and multi-span simply supported bridges were particularly susceptible to loss of support. Several aspects of the Chilean bridge design code are discussed and compared with North American codes (CSA S6 and AASHTO). [ABSTRACT FROM AUTHOR]

New technologies based on seismic isolation are gaining popularity among engineers given the savings on construction costs. The long-term advantage of these technologies preserve the serviceability of the structure after an earthquake and eliminate the cost of reconstruction. This advantage is critical for 'emergency' bridges, required to remain operational after an earthquake. The present article examines a method of isolating the foundation of existing bridges as part of a seismic retrofitting effort. This approach is supported by the increasing interest in this method, especially since its adoption by the Canadian standards and due to the fact that engineers are not too familiar with non-linear dynamic design methods. Another source of motivation is the opportunity to apply this technique to the refection of a few Quebec bridges. The steps of the antiseismic calculations as well as the results of non-linear analyses pertaining to the Madrid Bridge are presented and discussed. This paper may become a useful tool for engineers and their projects of retrofitting existing bridges. Les nouvelles technologies basées sur l'isolation sismique connaissent un intérêt grandissant parmi les ingénieurs, compte tenu de l'économie sur le coût de la construction de l'ouvrage qu'elles offrent. Elles présentent également un avantage indéniable à long terme étant donné qu'elles préservent la fonctionnalité de l'ouvrage après séisme et éliminent le coût de reconstruction. Cet avantage revêt une importance capitale pour les ponts dits de secours qui doivent demeurer en service après le séisme. Cet article présente une méthodologie relative à l'isolation de la base des ponts existants dans un contexte de mise en conformité sismique. Cette démarche est motivée par l'intérêt grandissant de cette méthode, notamment depuis son adoption par la norme canadienne d'une part et d'autre part par le fait que les ingénieurs praticiens sont moins familiers avec les méthodes dynamiques non linéaires de conception. L'opportunité offerte aux auteurs de mettre en application cette technique pour la réfection de quelques ponts au Québec est une autre source de motivation. Les étapes de calcul parasismiques sont pourvues, et les résultats des analyses non linéaires relatives au pont Madrid sont présentés et discutés. L'article est destiné aux ingénieurs praticiens qui y trouveront un outil utile pour leurs projets en réhabilitation de ponts existants. [ABSTRACT FROM AUTHOR]

The occurrence of one risk may exacerbate other risks or portfolios of risks due to their highly complex interrelated structures and existing interactions. Hence, the cumulative impact of a chain of risks may be greater than the sum of their individual impacts. Commonly practiced risk analysis approaches do not account for these interactions and face deficiency in providing reliable information regarding the actual impact of the identified risks. This paper presents a new approach to construction risk analysis where the interrelated structure of risks and their interactions have been modeled through the governing feedback loops. The proposed methodology is a system dynamics-based approach for risk analysis and assessment. The full impact of a risk or a set of risks may efficiently be modeled, simulated, and quantified in terms of time and cost by the proposed object-oriented simulation methodology. To evaluate the performance of the proposed methodology, it has been incorporated into a bridge construction project. The interrelated structures of the identified risks have been modeled and their cumulative consequences simulated and quantified as an illustrative example. La présence d’un risque peut augmenter la probabilité d’avoir d’autres risques ou ensembles de risques en raison de leurs structures et interactions existantes très complexes et étroitement liées entre elles. Ainsi l’impact cumulatif d’une chaîne de risques peut être plus grand que la somme des impacts individuels. Les analyses de risques effectuées couramment ne tiennent pas compte de ces interactions et sont insuffisantes pour fournir de l’information fiable quant à l’impact réel des risques identifiés. Cet article présente une nouvelle approche d’analyse des risques en construction dans laquelle les structures et interactions de risques existantes très complexes et étroitement liées entre elles ont été modélisées par des boucles de rétroaction principales. La méthodologie proposée est une approche basée sur la dynamique des systèmes pour l’analyse et l’évaluation des risques. Le plein impact d’un risque ou d’un ensemble de risques peut être modélisé, simulé et quantifié efficacement en termes de temps et de coûts par la méthode proposée de simulation orientée objet. Afin d’évaluer le rendement de la méthode proposée, nous l’avons utilisée dans un projet de construction d’un pont. La liaison étroite entre les risques identifiés a été modélisée et les conséquences cumulatives ont été simulées puis quantifiées dans un exemple illustratif. [ABSTRACT FROM AUTHOR]

The Canadian highway bridge design code (CHBDC) contains provisions for designing concrete members with fiber-reinforced polymer (FRP) reinforcement. In the second edition of the code, new shear design procedures for FRP-reinforced sections are provided. These procedures are consistent with those for steel-reinforced members in the code, in consideration of some modifications that account for the substantial differences between FRP and steel reinforcement. The shear approach adopted in the CHBDC follows the traditional approach of Vc + Vs for shear design. This paper presents an evaluation of this approach by comparing it with experimental shear strengths of available test data on beams longitudinally reinforced with FRP bars and with or without FRP stirrups. In addition, the CHBDC approach was compared with the FRP shear design provisions currently in effect in North America using the available test results. The comparison shows that the CHBDC method significantly underestimates the shear strength of FRP-reinforced concrete beams. A proposed modification to this method is presented and verified against available test results. Le Code canadien sur le calcul des ponts routiers (CCCPR) contient des dispositions pour la conception de membres de béton avec armature en polymères renforcés de fibres (PRF). Dans la 2e édition du code, de nouvelles procédures pour la conception de cisaillement pour les sections armées de PRF sont fournies. Ces procédures sont compatibles dans le code avec celles des membres armés d'acier en considérant certaines modifications pour tenir compte des différences substantielles entre les armatures en PRF et en acier. L'approche du cisaillement adoptée dans le CCCPR suit l'approche traditionnelle de Vc + Vs pour la conception du cisaillement. Cet article présente une évaluation de cette approche en la comparant à des forces de cisaillement expérimentales dans des données de test disponibles sur des poutres armées longitudinalement de barres de PRF, et sans ou avec étriers de PRF. En outre, l'approche du CCCPR a été comparée aux dispositions de conception de cisaillement PRF actuellement en vigueur en Amérique du Nord en utilisant les résultats de tests disponibles. La comparaison montre que la méthode du CCCPR sous-estime significativement la résistance au cisaillement des poutres armées en PRF. Une proposition de modification de cette méthode est présentée et vérifiée par rapport aux résultats des essais disponibles. [ABSTRACT FROM AUTHOR]

In the past quarter century, a number of bridges have been built that do not fit into the conventional types of cable-stayed bridges. These are under-deck cable-stayed bridges and combined cable-stayed bridges. In this paper we define the first of these two types and set out its mechanisms of response. We then establish and analyze the parameters that determine the permanent response and the response to live load of these bridges. Lastly, we draw conclusions relating to their behaviour and define design criteria for them with the aim of making cable-staying systems highly efficient and allowing the design of much lighter and slimmer structures. [ABSTRACT FROM AUTHOR]

At least 20 cable-stayed bridges have been built over the last 30 years that cannot be classified under existing typologies for cable-stayed bridges. These structures represent two new types of cable-stayed bridges that we herein define as "under-deck cable-stayed bridges" and "combined cable-stayed bridges." The evolution of these new bridge types is explored through consideration of the different proposals and structures that have been built throughout this period, pointing out the innovations made in each of them. In this paper we propose a new classification system for bridges prestressed by means of tendons into which these two new bridge types will fit. Studies that have been made of these structural types are also highlighted. On the basis of the aforementioned, we describe the state-of-the-art for these structural types, compiling and cataloguing information, documents, and knowledge that were previously highly dispersed. Lastly, we make a critical analysis of the current situation and draw some key conclusions. [ABSTRACT FROM AUTHOR]

The passage of river ice during the breakup event can have several effects on bridge structures. Design for ice passage at bridges has largely been empirical, such as the determination of superstructure clearance requirements based on historical stage data. As hydrologic and river ice processes in rivers are modified by climatic change, the use of empirical methods based on past observations and measurements could become less reliable. To advance beyond empiricism, it is necessary to develop rational design criteria based on a thorough understanding of the factors governing the interaction between bridges and ice. This concern applies especially during the breakup event when river flows, velocities, and hydrodynamic forces are usually higher and moving ice is thicker and stronger than during freeze-up. This paper provides guidance on the design of bridges to minimize ice impacts on the structure during the breakup period. [ABSTRACT FROM AUTHOR]

This paper presents a synthesis of the design provisions of the second edition of the Canadian Highway Bridge Design Code (CHBDC) for fibre-reinforced structures. New design provisions for applications not covered by the first edition of the CHBDC and the rationale for those that remain unchanged from the first edition are given. Among the new design provisions are those for glass-fibre-reinforced polymer as both primary reinforcement and tendons in concrete; and for the rehabilitation of concrete and timber structures with externally bonded fibre-reinforced-polymer (FRP) systems or near-surface-mounted reinforcement. The provisions for fibre-reinforced concrete deck slabs in the first edition have been reorganized in the second edition to explicitly include deck slabs of both cast-in-place and precast construction and are now referred to as externally restrained deck slabs, whereas deck slabs containing internal FRP reinforcement are referred to as internally restrained deck slabs. Resistance factors in the second edition have been recast from those in the first edition and depend on the condition of use, with a further distinction made between factory- and field-produced FRP. In the second edition, the deformability requirements for FRP-reinforced and FRP-prestressed concrete beams and slabs of the first edition have been split into three subclauses covering the design for deformability, minimum flexural resistance, and crack-control reinforcement. The effect of sustained loads on the strength of FRPs is accounted for in the second edition by limits on stresses in FRP at the serviceability limit state. [ABSTRACT FROM AUTHOR]

The ISIS Canada Networks of Centres of Excellence (NCE) program has focused on two main themes to improve civil engineering infrastructure, namely innovative construction technologies, and structural health monitoring (SHM). The former began with the construction of the first field application of the innovative steel-free concrete bridge deck slab technology at the Salmon River bridge, Nova Scotia, in 1995. Although this bridge has continued to function safely under heavy traffic loads, it has developed characteristic longitudinal cracking of the concrete between adjacent girders due to fatigue. This paper describes the recent research to develop an SHM model for monitoring the impact and stability of this cracking. Theoretical and experimental models were used to examine the change in response as cracking develops. A global load distribution matrix was proposed, and the variation in load distribution values with cracking was used to develop a cracking index that can be employed in monitoring the field structure. [ABSTRACT FROM AUTHOR]

This paper presents a new method for deck-to-girder connections of glass fibre reinforced polymer (GFRP) bridge decks. To design the connection system, a GFRP deck in a rectangular cross-sectional shape is considered. The size of the shear bolts, bolt location, bolt spacing, and the size and type of stiffening plate are the variables considered in the design. The behavior of the proposed deck-to-girder connection system was analysed using commercial finite element analysis software. The failure of the connection system was checked by the Tsai–Hill criterion. Effective deck-to-girder connection details for GFRP bridge decks are identified and presented based on the results of the analysis. [ABSTRACT FROM AUTHOR]

This paper presents an analytical approach for predicting the length limits of integral bridges built on cohesive soils based on the flexural strength of the abutments and the low cycle fatigue performance of the steel H-piles at the abutments under cyclic thermal loading. First, H-piles that can accommodate large inelastic deformations are determined considering their local buckling instability. Then, a damage model is used to determine the maximum cyclic deformations that such piles can sustain. Next, nonlinear static pushover analyses of typical integral bridges subjected to cyclic thermal variations are conducted to study the effect of various geometric, structural, and geotechnical parameters on their performance. Equations are derived by using the analyses results to determine the maximum length limits of integral bridges built on cohesive soils. It is found that the maximum length limits of integral bridges is affected by the stiffness of the deck, height of the abutment, properties, and orientation of the piles as well as stiffness of the cohesive soils. [ABSTRACT FROM AUTHOR]

The problem of punching shear usually arises in reinforced concrete slabs subjected to concentrated loads and particularly in concrete bridge decks due to development of an internal arching system. Ongoing research revealed that the governing mode of failure of concrete bridge decks is not flexure and that using a flexural design method usually led to unnecessary high levels of steel reinforcement. This paper examines the applicability of nonlinear finite element formulation of restrained concrete bridge decks. A general purpose finite element program ANACAP was employed in this study. The accuracy of the nonlinear finite element analysis is demonstrated using test results conducted by other researchers. The results of the finite element analysis are also compared with those obtained from a rational model. The experimental results and the theoretical model provide insight to the fundamental behavior of concrete bridge decks. [ABSTRACT FROM AUTHOR]

Design and assessment of highway bridges requires accurate prediction of the extreme load effects expected during the proposed or remaining life of the structure. Traditionally these effects are calculated using conservative codified deterministic loading models. While this conservatism is relatively insignificant in design, it may be critical in assessment. Advances in weigh-in-motion (WIM) technology, i.e., the process of weighing trucks travelling at full highway speeds, have increased the availability of accurate and unbiased site-specific traffic records. Assessments performed using WIM data are generally accepted as less conservative than those performed using generalized codified loading models. This paper briefly describes traffic simulation using WIM statistics. The implications of the accuracy of the recorded data and the duration of recording and of the sensitivity of the extreme to the method of prediction are investigated. Traffic evolution with time is also explored. The conclusions are of interest to engineers performing assessment of existing bridges. [ABSTRACT FROM AUTHOR]

The past experimental studies to investigate the backwater effects due to bridge constrictions have been mostly performed in setups of single rectangular channels with fairly smooth surfaces. Therefore, there is a need to investigate more realistic cross-sectional shapes and roughness conditions. The most obvious case is to consider bridges in natural channels with floodplains. This paper reports the findings of model testing of arch and straight deck bridge constrictions in a compound channel flume with both smooth and roughened surfaces. Four different types of bridge models, namely single opening semicircular, multiple opening semicircular, single opening elliptic, and straight deck models with and without piers, were used in the testing program. An attempt was made to develop a simple formula for estimating bridge backwater as a function of Froude number and opening ratio. [ABSTRACT FROM AUTHOR]

This paper describes results from a study of the dynamic performance of the Confederation Bridge during traffic load tests and a storm with high winds that occurred at the bridge site on 7 November 2001. The traffic load tests were conducted over a three-span segment of the bridge and consisted of single and double truck configurations at different speeds. The winds during the storm of 7 November 2001 were the strongest that have ever been measured at the bridge site since the opening of the bridge. The vibrations of the bridge during both the load tests and the storm were recorded by a network of 76 accelerometers. By processing the recorded vibrations, vertical deflections and dynamic amplification factors due to the traffic load tests and vertical and lateral deflections due to the wind during the storm were computed. The computed values were compared with those used in the design. It was found that both the deflections and the dynamic amplification factors were much smaller than the design values. [ABSTRACT FROM AUTHOR]

In this paper, the analytical and experimental results of tests on a benchmark and a damaged circular bridge column are presented. The benchmark column is a 40% scale reinforced concrete circular bridge column damaged as a result of shear failure during a cyclic-loading test; the benchmark column was then repaired by epoxy and non-shrinkage mortar and rehabilitated by carbon fiber reinforced plastic (CFRP) after the cyclic-loading test. The benchmark bridge column is tested under a cyclic-loading test with constant axial load. The result shows that the column suffered shear failure at low displacement ductility. Non-shrinkage mortar with high-pressure epoxy injection was used to repair the damaged bridge column, and then three-layer CFRP was used to rehabilitate the shear strength of the bridge column. The test result shows that the repaired and rehabilitated column develops significantly improved hys ter etic responses at high displacement ductility. The analytical lateral force – displacement relationship of the bridge columns can accurately predict the experimental result, especially in the nonlinear region. [ABSTRACT FROM AUTHOR]

During the past decade, composite steel-free deck bridges came to reality in Canada through the construction of five bridges. The new structural system enables the construction of a concrete deck that is totally devoid of all internal steel reinforcement. Traditionally, reinforced concrete bridge decks are designed to sustain loads in flexure. The steel-free deck bridge system develops internal compressive forces "internal arching," which leads to failure by punching shear at substantially higher loads than the flexural design load. The fibre-reinforced concrete deck is usually attached to the steel girders through flexible shear connectors. These steel girders are transversely tied together by steel straps and cross frames. In this paper, the concept of the new bridge system is briefly discussed. The generations of the deck slabs are introduced. Brief outlines of the bridges built to date with this new technology are presented. A three-dimensional finite element model is then proposed to study the behaviour of the main structural component of the new system. The model is verified against previous experimental results and is used to perform a parametric study on some aspects which are thought to significantly affect the behaviour of the new steel-free deck bridge system.Key words: bridges, composite girders, finite element method, steel-free deck, steel straps.Durant la dernière décennie, les ponts à tablier composé sans acier sont devenus réalité au Canada grâce à la construction de cinq ponts. Ce nouveau système structural permet la construction d'un tablier en béton qui est complètement dépourvu de tout renforcement interne en acier. Traditionnellement, les tabliers de pont en béton armé sont conçus afin de supporter des charges en flexion. Le système de tablier de pont sans acier développe des forces internes en compression « cintrage interne » et résulte en une rupture par poinçonnement en cisaillement pour une charge substantiellement plus grande que les charges en flexion de conception. Le tablier en béton renforcé de fibres est habituellement attaché aux poutres d'acier à l'aide de connexions de cisaillement flexibles. Ces poutres d'acier sont attachées ensemble transversalement à l'aide de liens d'acier et de contreventements. Dans cet article, le concept de ce nouveau système est brièvement discuté. Les générations des tabliers en dalles sont introduites. Un bref aperçu des ponts construits à ce jour avec cette nouvelle technologie est présenté. Un modèle par éléments finis tirdimensionnel est par la suite proposé afin d'étudier le comportement des composants structurels principaux du nouveau système. Le modèle est confronté aux résultats expérimentaux obtenus par d'autres dans le passé. Ensuite, il est utilisé afin de performer une étude paramétrique sur quelques aspects qui sont suspectés d'affecter de façon significative le comportement de ce nouveau système de tablier de pont sans acier.Mots clés : ponts, poutres composées, méthode par éléments finis, tablier sans acier, liens d'acier.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

This paper presents generalized design equations for concrete–steel composite girders. The equations evaluate the ultimate positive and negative flexural resistances of a composite section by addressing the issues of different design classes, varying locations of the neutral axis, and the possibility for either pseudoplastic or elastoplastic design. The equations may be readily implemented into design programs or spreadsheets.Key words: bridge, composite girders, design equations, elastic, elastoplastic, plastic, psuedoplastic.Cet article présente des équations généralisées de conception servant au calcul des poutres composées faites d'acier et de béton. Les équations évaluent les résistances ultimes en flexion, positive et négative, d'une section composée. Pour ce faire, les différentes classes de conception ont été considérées, la position de l'axe neutre a été variée et la possibilité d'un conception pseudo-plastique aussi bien qu'élasto-plastique a été envisagée. Les équations peuvent désormais être mises en œuvre au sein des programmes de conception ou des tableurs.Mots clés : pont, poutres composées, équations de conception, élastique, élasto-plastique, plastique, pseudo-plastique.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

The rehabilitation of highway and road bridges is without any question one of today's major challenges. It is to keep up with this challenge that this paper presents an innovative bridge rehabilitation technique which consists in using aluminum decking to replace deteriorated bridge decks. Numerical modeling was carried out on a favored type of decking in order to study and analyze its performance under Canadian traffic loads. Also, an economic analysis was made on a case-study bridge, in order to compare the costs of the proposed technique to the cost of the method currently used by the Quebec Ministry of Transportation for the rehabilitation of certain types of bridge deck.Key words: aluminum, bridge, deck, economic study, extrusion, grid method, rehabilitation.La réhabilitation des ponts routiers est sans conteste un défi majeur de nos jours. C'est pour contribuer à relever ce défi que le présent article présente une technique innovatrice de réhabilitation des ponts qui consiste à remplacer le tablier de certains types de ponts existants par un tablier en aluminium. Un système intéressant de tablier de pont en aluminium a été analysé numériquement pour évaluer sa performance sous les charges routières canadiennes. De plus, une analyse économique a été réalisée sur un pont existant, dans le but de comparer les coûts de la technique proposée à ceux de la méthode généralement utilisée par le Ministère des Transports du Québec pour la réhabilitation de certains types de tabliers de ponts.Mots clés : aluminium, étude économique, extrusion, méthode du grillage, pont, réhabilitation, tablier. [ABSTRACT FROM AUTHOR]

The study presented in this paper is part of a project aiming at evaluating the potential use of aluminum in structures. The types of intervention could range from a simple repair or a reinforcement involving structural aluminum, the replacement of a used bridge deck by an aluminum deck, to the construction of a new bridge made in full or in part of aluminum. It is this latter type of intervention that justified a research project, the results of which are presented in this article. The first step involves identifying the most advantageous type of aluminum structural system from a structural standpoint as well as an economic standpoint. This step includes the analysis and partial design of 40 girder- or truss-type road bridges, spanning 15 and 35 m, supporting either an active concrete slab or an aluminum deck. These studies have shown that bridges built using a Pratt-type truss and an active concrete slab provided the best results. It is also shown that some calculation criteria, such as vibration, deflection, and fatigue criteria limited the extensive use of aluminum in bridges. In the second step, nine bridges are more comprehensively analysed and designed, based on the standards used in North America, and three are fully designed, including the connexions, in order to realize a cost analysis study that is as accurate as possible. Special attention is given to vibration and fatigue problems as well as to the details related to connexions calculation. The study concludes that the development of an aluminum-only medium span road bridge system is a non-viable project in the short to mid term from a structural standpoint as well as an economic standpoint, and it makes recommendations on the use of aluminum decks and on the continuation of the work.Key words: aluminum, analysis, bridges, connexions, design, fatigue, standards, vibration.[Journal translation]L'étude présentée dans cet article s'inscrit dans le cadre d'un projet visant à évaluer le potentiel d'utilisation de l'aluminium dans les ouvrages d'art. Le type d'intervention peut être une simple réparation ou un renforcement impliquant de l'aluminium structural, le remplacement d'un tablier de pont usagé par un tablier en aluminium ou, encore, la construction d'un nouveau pont entièrement ou en grande partie en aluminium. C'est ce dernier type d'intervention qui a justifié le projet de recherche dont les résultats font l'objet de cette présentation. Une première étape vise à identifier le type de système structural en aluminium le plus avantageux, tant du point de vue structural que du point de vue économique. Cette étape comprend l'analyse et le dimensionnement partiel de 40 ponts routiers de types poutres pleines ou à treillis, de 15 et 35 m de portée et supportant soit une dalle de béton participante, soit un tablier en aluminium. Ces travaux ont démontré que les ponts ayant des poutres triangulées de type Pratt et une dalle participante en béton armé présentent les meilleurs résultats. Il en ressort aussi que certains critères de calcul, tels les critères de vibration, de flèche et de fatigue limitent grandement l'utilisation de l'aluminium dans les ponts. Dans une deuxième étape, neuf ponts sont analysés et dimensionnés plus finement sur la base des normes en vigueur en Amérique du Nord et trois sont dimensionnés au complet, y compris les assemblages, dans le but de réaliser une étude comparative des coûts la plus précise possible. Une attention spéciale est portée aux problèmes de vibration et de fatigue ainsi qu'aux particularités du calcul des assemblages. L'étude conclut que le développement d'un système de pont routier entièrement en aluminium, de moyenne portée, est un projet non viable à court ou à moyen terme, tant du point de vue structural que du point de vue économique et fait des recommandations sur l'utilisation des tabliers en aluminium ainsi que sur la poursuite des travaux.Mots clés : aluminium, analyse, assemblages, dimensionnement, fatigue, normes, ponts, vibration. [ABSTRACT FROM AUTHOR]

The main focus of the paper is the framework for analysing ice loads on the Confederation Bridge across the Northumberland Strait, using probabilistic methods. Safety targets were given as a beta factor of 4.0 for a 100-year lifetime, amounting to a probability of failure of about 3 × 10[sup -7] per year. The ice regime comprises rafted and ridged ice, and peak loads are expected during March and April of each year. A simulation method was developed, in which loads are calculated corresponding to individual interactions associated with ridges in the ice floes that traverse the strait. The floes are driven by environmental driving forces, and the highest loads occur when these exceed the ridge failure loads. The load results from failure of the consolidated layer and rubble keel. Methods for the analysis of this are described. The determination of extreme loads depends on the number of interactions per year. Difficulties in modelling are described, together with techniques for analysis, such as updating of probability distributions given an interaction. Many of these techniques were derived from work related to the Beaufort Sea oil exploration. The results reflect a best-estimate approach to those parameters for which information was sketchy, or unavailable. They are therefore conditional on those estimates, but as the results are largely insensitive to these, the potential for error is minimal. There are a number of parameters (e.g., friction coefficient) that do have a significant effect and for which all those involved in the effort would have wished better definition. This sensitivity is reflected in the two sets of results presented in the paper.Key words: ice, forces, probabilistic, safety, bridges, modelling.Cet article se concentre principalement sur le cadre de travail pour l'analyse des charges de glace sur le pont de la Confédération enjambant le détroit de Northumberland, et ce, en utilisant des méthodes probabilistes. Les objectifs de sécurité sont basés sur un facteur beta de 4,0 pour une durée de vie de 100 ans, resultant en une probabilité de rupture de 3 × 10[sup -7] par an. Le régime de glace comprend de la glace en paquet et en récif, et les charges de pointe sont espérées durant mars et avril de chaque année. Une méthode de simulation a été développée, dans laquelle les charges sont calculées selon les interactions individuelles associées avec les récifs dans les banquises de glace traversant le détroit. Les banquises sont acheminées par les forces environnementales dominantes, et les plus grandes charges se produisent lorsqu'elles excèdent les charges de rupture des récifs. La charge est le résultat de la rupture de la couche consolidée et de la quille en débris. Les méthodes pour l'analyse de cela sont décrites. La détermination des charges extrêmes dépend du nombre d'interactions par année. Les difficultés de modélisation sont décrites, de même que des techniques pour l'analyse, telle que l'ajustement des distributions de probabilité sur la base d'une interaction. Plusieurs de ces techniques sont dérivées de travaux reliés à l'exploration pétrolière dans la mer de Beaufort. Les résultats réflètent une approche dite de la meilleure estimation de ces paramètres, pour lesquels les données sont sommaires ou non disponibles. Ils sont donc conditionnels à ces estimations, mais puisque les résultats sont largement insensibles à celles-ci, le potentiel d'erreur est minime. Il y a certains paramètres (e.g., le coefficient de friction) qui ont un effet significatif, et pour lesquels tous ceux impliqués dans l'effort auraient voulu une meilleure définition. Cette sensibilité est réflétée dans les deux séries de résultats présentés dans cet article.Mots clés : glace, forces, probabiliste, sécurité, ponts, modélisation.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Composite beams with corrugated steel webs represent a new innovative system which has emerged in the past decade for short and medium span bridges. The new system usually combines the usage of corrugated steel plates as webs and reinforced/prestressed concrete slabs as flanges for plate or box girders. Bridges that have been recently built with this hybrid system are outlined in this paper, which focuses on the advantages of using corrugated steel webs as opposed to traditional flat webs. The flexural behaviour and bearing resistance of girders with corrugated steel webs is briefly discussed. The flanges of the new system solely provide the flexural strength of the beam with no contribution from the corrugated web. On the other hand, the corrugated web provides the shear capacity of the system. Thus, the shear behaviour of girders with corrugated webs is explicitly discussed focusing on the different failure and (or) buckling modes that affect the design of the corrugated steel web plates. Design charts for such webs are constructed based on the different interaction equations of failure. The torsion-warping behaviour of composite box girders with corrugated steel webs is also discussed.Key words: bridges, composite beams, corrugated steel webs, global buckling mode, interactive buckling, local buckling.Les poutres composées avec des âmes d'acier ondulées représentent un nouveau système innovateur, qui a émergé dans la dernière décennie pour des ponts de courte et moyenne portée. En général, ce nouveau système combine l'utilisation de plaques d'acier ondulées en tant qu'âmes avec des dalles de béton armé/précontraint en tant qu'ailes afin de former des poutres de type plaque ou boîte. Des ponts, qui ont été récemment construits selon ce système hybride, sont mis en lumière dans cet article, qui se concentre sur les avantages d'utiliser des âmes d'acier ondulées par opposition à des âmes traditionnelles plates. Le comportement en flexion et la résistance au chargement des poutres sont discutés brièvement. Seules les ailes de ce nouveau système fournissent la résistance en flexion de la poutre, puisqu'il n'y a pas de contribution provenant de l'âme. Cependant, l'âme ondulée fournit la capacité contre le cisaillement du système. Donc, le comportement en cisaillement de poutres avec des âmes ondulées est discuté explicitement, avec une attention particulière donnée sur les différents modes de défaillance et/ou flambage qui affectent la conception des plaques d'âmes d'acier ondulées. Des graphiques de conception pour de telles âmes sont construits sur la base des différentes équations d'interaction pour la défaillance. Le comportement en torsion-gauchissement de poutres de type boîte avec des âmes d'acier ondulées est aussi discuté.Mots clés : ponts, poutres composées, âmes d'acier ondulées, mode de flambage global, flambage interactif, flambage local.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Culverts constructed of whole truck tires are a cost-effective alternative for draining water from small drainage basins with areas up to several hectares. Truck tire culvert design involves both hydraulic and structural performance considerations. This paper focuses on the structural considerations. Structural performance of truck tire culverts depends on the strength and stiffness of the truck tires and on their interaction with the surrounding backfill soil. The strength and stiffness properties of truck tires were determined by parallel plate testing. Field tests were conducted to evaluate the soil-structure interaction of buried truck tire culverts under a relatively shallow backfill. Responses with well-compacted and uncompacted (dumped) glacial till backfill soil were compared. Drawing on the results of the parallel plate tests and using the buried conduit test results for calibration, the Culvert Analysis and Design (CANDE) program was used to assess the load response of a truck tire culvert for a variety of backfill soils and to develop structural performance-based design guidelines.Key words: scrap tires, culvert, parallel plate test, field testing, CANDE.Les ponceaux construits à partir de pneus de camions sont une alternative économique pour drainer les eaux de petits bassins de drainage avec une superficie jusqu'à plusieurs hectares. La conception de ponceaux en pneus de camions implique la considération des performances hydraulique et structurale. Cet article se concentre sur les considérations d'ordre structural. La performance structurale de ponceaux en pneus de camions dépend de la résistance et de la rigidité des pneus de camions, de même que de leurs interaction avec le matériau de remblayage environnant. Les propriétés en résistance et en rigidité des pneus de camions ont été determinées par des test sur plateaux parallèles. Des tests sur le terrain ont été conduits pour évaluer l'interaction sol-structure de ponceaux en pneus de camions enterrés sous une remblayage relativement peu profond. Les réponses avec une moraine compactée et non compactée (déchargée) comme matériau de remblayage ont été comparées. Se basant sur les résultats des tests sur plateaux parallèles et en utilisant les résultats des tests sur les conduites enterrées pour la calibration, le programme « Culvert Analysis and Design » (CANDE, Analyse et conception de ponceaux) a été employé pour évaluer la réponse en chargement d'un ponceau en pneus de camions pour une variété de matériaux de remblayage et pour développer des guides de conception basés sur la performance structurale.Mots clés : pneus usagés, ponceau, test sur plateaux parallèles, test sur le terrain, CANDE.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]