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Adhering to ASTM C109/C109M-20 standards ensures quality in cement mortar specimens. However, achieving the required sand gradation per ASTM C778-21 can be challenging. This paper presents a faster method for adjusting sand gradation without compromising ASTM quality standards. The proposed method involves analyzing six silica sand samples of different gradations, pre-screening sands, using Excel Solver for optimal mixture ratios, making automated gradation tweaks with precise calculations, and validating the gradation to ensure ASTM compliance. After making the adjustments, compressive strength tests were conducted on mortars with the modified sands, and the results were compared with those of standard-graded sand. Based on statistical analysis, the new method yielded reliable outcomes with compressive strengths similar to standard sands. This innovation offers a more efficient alternative, paving the way for streamlined practices in civil engineering. [ABSTRACT FROM AUTHOR]

This review paper presents the current state-of-the-art pertains to water pipe failure prediction and risk assessment, published in the last ten years (2009–2019). This paper has been motivated by the lack of comprehensive review articles that integrates water network failure and risk modeling. Some of the current practices reviewed the pipe condition and its failure. Others focused on the statistical prediction models, whereas the rest outlined failure prediction models of large diameter mains only. The mainstream of the current practice, highlighted in this paper characterizes the structural deterioration and failure rates using various statistical techniques, whereas the remainder of research covers a proliferation of machine learning and soft computing applications to forecast and model the pipeline risk of failure. The review offers descriptions of the models together with their proposed methodologies, algorithms and equations, contributions and drawbacks, comparisons and critiques, and types of data used to develop the models using the bibliographic review method. Finally, future work and research challenges are recommended to assist the civil engineering research community in setting a clear agenda for the upcoming research. [ABSTRACT FROM AUTHOR]

Designing telecommunication towers to withstand wind loads requires specific considerations, which has led the international civil engineering community to develop specific standards for these structures. The recent internationalization of the construction business has made it imperative for engineers to acquire knowledge and interpretation of codes from different countries. In light of the 2018 update of Canadian Standard CSA-S37-18 (CSA), evaluating its differences against other international standards for telecommunication towers has become important. This paper presents a comparison of the wind loading specifications for self-supporting telecommunication towers according to CSA; Australian Standard; Eurocode EN-1993-1; and US Standard TIA-222-G. The different standards have also been evaluated with respect to the values of the axial forces and the elements ratio for two self-supporting telecommunication towers. The parameters related to the wind profiles and the gust effect factor presented the highest difference between the standards. [ABSTRACT FROM AUTHOR]

Greater opportunity now exists compared to 35 years ago for civil engineers to apply river ice knowledge to practical problems of planning, designing, and operating hydro-power facilities, water intakes, bridges, and other infrastructure along ice-covered rivers. This is due to major advancements made during this period in understanding the physical processes of river ice formation, growth and breakup, in developing instrumentation for acquisition of information on winter environments, and in developing numerical modelling tools. An increasing number of journal articles, as well as papers presented at the river ice workshops of the CGU Committee on River Ice Processes and the Environment (CRIPE) and the ice symposia of the International Association for Hydro-Environment Engineering and Research (IAHR) attest to the advancement in river ice science and engineering knowledge that has occurred during the past 35 years. This paper reviews the developments in river ice science and engineering from a Canadian perspective and briefly discusses future directions. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to develop an estimation model for major stream delays at an unsignalized intersection under limited priority conditions. The key idea of this paper is that, when the minor stream drivers accept smaller major stream gaps, some drivers on the major road have to slow down their speeds and adjust their relative positions to avoid traffic accidents, incurring some delays. Assuming that headways in the major stream follow the M3 distribution, the delay for the first major stream vehicle after a limited priority merge is presented using acceptance gap theory and probability theory, and then recursive models are developed for the following major stream vehicles before the next merge. Finally, the precision of the method proposed in this paper is calibrated using field survey data from Changchun city, China, and the results show that the maximum, minimum, and average relative error of the 12 samples are approximately 30.38%, 9.04%, and 18.97%, respectively. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to first provide relevant information about the historic seismicity of the island of Haiti, the tectonic setting and the identification of the unmapped Léogâne fault which is now believed to have been the main cause of the 12 January 2010 Haiti earthquake. The paper then focuses on the state of construction in Haiti, with particular emphasis given to engineered buildings. The lack of a building code and standards for the design of structures, as well as the fact that seismic forces were not considered in the design of most buildings explains the failure of so many engineered structures. Several examples are given and arranged according to building function. Since the earthquake has occurred, interim measures have been implemented to control construction of new buildings. Some recommendations are given to improve construction practice in Haiti for the reconstruction. [ABSTRACT FROM AUTHOR]

Several parabolic-shaped open channel sections are available in the literature, including quadratic and semi-cubic parabolic sections. This paper presents a three and one-third parabolic cross-section that has superior characteristics compared to those of previous parabolic-shaped sections. The section characteristics, including two approximate formulas for the wetted perimeter and a simple iterative formula for the normal water depth are presented. The exact solution for the most efficient hydraulic section is derived. The results show the width-depth ratio for the most efficient hydraulic section is 2.1273. Practical applications of the proposed most efficient hydraulic section are presented, including direct formulas for the discharge and explicit formulas of normal and critical depths. The results show that the proposed section improves the hydraulic characteristics compared with other parabolic sections and trapezoidal section. [ABSTRACT FROM AUTHOR]

This paper presents a sensitivity analysis of the hierarchical decomposition of networks in the context of seismic vulnerability of power systems. The sensitivity analysis is evaluated by varying the fragility curves and clustering algorithms on the vulnerability measure. For the fragility curves, four different curves are used. For sensitivity to clustering, four representative spectral clustering algorithms are used: SM, KVV, NJW, and Meila-Shi algorithms. The resulting vulnerability rankings are compared for a common case study (IEEE-118 test case) in terms of: correlation, identification of critical nodes, and identification of common clusters. The results show the robustness of the methodology with respect to variation of the fragility curves. On the other hand, the selection of the clustering algorithm is found to be a decisive parameter depending on application. If the application requires identification of critical elements a better performance is found. [ABSTRACT FROM AUTHOR]

Disposal of sediments during land reclamation and dredging is an important component in many environmental engineering projects. Dredged material can be discharged into the ambient water either instantaneously to form a particle cloud or continuously to form a slurry jet. This paper presents the results of laboratory experiments to understand the dynamics of particle cloud in stagnant water. Different independent parameters such as particle size, nozzle diameter, cumulative mass of sand particles, and release height were tested. Due to wide ranges of selected variables and interactions between parameters, response surface methodology (RSM) technique was employed to determine the importance and effectiveness of each parameter on the growth and motion of particle clouds. A narrow range of non-dimensional cloud buoyancy in thermal regime was selected for design of experiments. Particle size was found to be the most significant parameter for the response predictions. The RSM results showed that increasing the nozzle diameter from 5 mm to 14 mm slightly increased the cloud width if all other parameters were kept unchanged. Statistical analysis of results indicated that the effect of the release height on growth of particle cloud was not significant; however, it was effective on variations of frontal velocity. [ABSTRACT FROM AUTHOR]

Design-build (DB) is adopted as a project delivery method in hopes to improve performance. Previous studies focus on upstream issues such as conditions for adoption and contractor selection, but few address the design and construction coordination issues that are very likely to be encountered in execution by new users. This paper investigates coordination problems arising from design and construction concurrence and solutions by studying five ongoing DB projects and interviewing nine major contract parties. Inconsistent application of the design and construction process and infrequent feedback are two major problems found to have high influence on DB execution. A work unit planning process with five steps is presented in this paper to help better manage the design and construction coordination of a DB project. [ABSTRACT FROM AUTHOR]

This paper demonstrates how fuzzy expert systems can be integrated within discrete event simulation models to enhance their modeling and predictive capabilities for construction engineering applications. A proposed methodology is presented for extracting the information from experts to develop the fuzzy expert system rules. The developed fuzzy expert system is integrated within a discrete event simulation model to enhance its modeling capability by explicitly accounting for the different factors affecting some of the simulation activities. A tunneling case study is used to illustrate the features of the integrated system. The outputs generated from the integrated system are very comparable to those from the original probabilistic simulation model. The integrated system represents a more realistic modeling scenario, since it thoroughly accounts for the different factors affecting the tunnel boring machine (TBM) advance rate. This paper is relevant to researchers because it provides an advance in combining artificial intelligence techniques with simulation models to yield better tools for construction modeling. It is of relevance to practitioners because it provides a useful tool for modeling construction engineering problems. [ABSTRACT FROM AUTHOR]

A slow-moving heavy vehicle can substantially reduce traffic flow because the vehicle acts as a moving bottleneck. In particular, the bottleneck can be initiated on a long uphill freeway section where heavy trucks gain little acceleration and propagate upstream when the percentage of loaded trucks in the traffic is high. This paper finds an interesting relation between the bottlenecks and some physical factors including heavy vehicle characteristics, road geometry, traffic flow theory, and percentage of trucks in traffic. According to this relation, the paper provides two dimensionless physical parameters to characterize the formation and propagation of the queues initiated by loaded trucks on uniform upgrades, respectively. Based on the critical values of these parameters aforementioned, the paper can help transportation engineers to determine that the number of design lanes under the conditions that the growing bottlenecks initiate along upgrade section cannot be resolved by simply using equations and rules suggested in the 2000 edition of the Highway capacity manual. Un véhicule poids lourd lent peut réduire considérablement le courant de circulation parce qu’il agit comme un entonnoir mobile. Plus particulièrement, l’entonnoir peut être enclenché sur une longue section d’autoroute en montée où les poids lourds peuvent difficilement accélérer; cet entonnoir peut se propager vers l’aval lorsque le pourcentage de poids lourds est élevé dans la circulation. Cet article présente une relation intéressante entre les entonnoirs et certains facteurs physiques, dont les caractéristiques des poids lourds, la géométrie des routes, la théorie du courant de circulation et le pourcentage de camions dans la circulation. Selon cette relation, l’article fournit deux paramètres physiques sans dimension pour caractériser respectivement la formation et la propagation des queues initiées par les camions chargés lorsqu’ils sont sur des montées uniformes. En se basant sur les valeurs critiques de ces paramètres, l’article peut aider les ingénieurs des transports à déterminer le nombre de voies à implanter selon sous les conditions que les entonnoirs croissants enclenchent le long des sections en montée et qui ne peut être déterminées simplement en utilisant les équations et les règles proposées dans l’édition 2000 du guide Highway capacity manual. [ABSTRACT FROM AUTHOR]

This paper focuses on the development of equivalent mechanical models for tuned liquid dampers (TLDs) with rectangular, vertical-cylindrical, horizontal-cylindrical, and hyperboloid (conical) tank shapes under external excitation in the transverse direction. Potential flow theory is utilized to obtain the free-surface response amplitude and the corresponding velocity of the sloshing liquid and Lagrange’s equations are used to determine the generalized properties. Morison’s equation and the virtual work method are used to estimate an equivalent viscous damping ratio based on the screen loss coefficient. The equivalent mechanical properties derived in this paper model the fundamental sloshing mode only and are restricted to small response amplitudes. Subsequently, the equivalent mechanical properties including effective mass, natural frequency, and damping ratio of the TLDs, having different tank geometries, are compared. It is found that the effective mass values for horizontal-cylindrical and hyperboloid TLDs are larger than the effective mass values for vertical-cylindrical and rectangular TLDs. The increased effective mass values for horizontal-cylindrical and hyperboloid TLDs can result in improved tuned liquid damper performance given the same total liquid mass as that of rectangular or vertical-cylindrical TLDs. Cet article traite du développement de modèles mécaniques équivalents pour les amortisseurs liquides accordés (« TLDs ») avec des réservoirs rectangulaires, verticaux-cylindriques, horizontaux-cylindriques et hyperboloïdes (coniques) sous une excitation externe dans la direction transversale. La théorie de l’écoulement potentiel est utilisée pour obtenir l’amplitude de la réponse à la surface libre ainsi que la vitesse correspondante du liquide ballottant; les équations de Lagrande sont utilisées pour déterminer les propriétés générales. L’équation de Morison et la méthode de travail virtuel sont utilisées pour estimer un rapport d’amortissement visqueux équivalent en se basant sur le coefficient de perte des grilles de tamisage. Les propriétés mécaniques équivalentes dérivées dans cet article modélisent le mode de ballottement de base uniquement et elles sont limitées aux faibles amplitudes de réponse. Ainsi, les propriétés mécaniques équivalentes sont comparées, dont la masse apparente, la fréquence naturelle et le rapport d’amortissement des « TLDs » ayant différentes géométries de réservoir. Il s’est avéré que les valeurs de masse apparente pour les « TLDs » avec réservoirs horizontaux-cylindriques et hyperboloïdes sont supérieures aux valeurs de masse apparente pour les « TLDs » avec réservoirs rectangulaires et verticaux-cylindriques. L’augmentation des valeurs de masse apparente pour les « TLDs » avec réservoirs horizontaux-cylindriques et hyperboloïdes peut engendrer une amélioration du rendement des « TLDs » pour une masse totale de liquide identique à celle des « TLDs » avec réservoirs rectangulaires ou verticaux-cylindriques. [ABSTRACT FROM AUTHOR]

Modern roundabouts have been found to improve safety and reduce overall delay, but they may have negative impacts on the safety of cyclists as other vehicles may cut-off cyclist paths while entering or exiting the roundabout. Several before-after studies have found an increase in traffic collisions involving cyclists at roundabouts after being converted from conventional signalized intersections. Another concern associated with roundabouts is the safety of pedestrians, especially pedestrians with severe vision impairment who may find difficulty in negotiating roundabouts. This paper evaluates safety and operational impacts of using bicycle bypass lanes at roundabouts as a means of increasing the safety of cyclists. The paper also recommends the full utilization of pedestrian traffic signals, proposed by other studies, by incorporating them with the proposed bicycle bypass lanes. An evaluation scheme involving the safety benefits and the costs of the proposed bypass lanes is provided to help practitioners decide when they are warranted. The evaluation scheme is illustrated using an application example. Les carrefours giratoires modernes ont amélioré la sécurité et réduit les délais en général, mais ils peuvent avoir des effets négatifs sur la sécurité des cyclistes puisque les autres véhicules peuvent couper le chemin aux cyclistes en entrant ou en sortant des carrefours giratoires. Plusieurs études de type avant-après concluent à une augmentation des collisions de la route impliquant des cyclistes dans les carrefours giratoires fraîchement convertis d’intersections conventionnelles signalées. Une autre inquiétude reliée aux carrefours giratoires est la sécurité des piétons, particulièrement les piétons ayant des déficiences visuelles graves qui peuvent trouver difficile de traverser les carrefours giratoires. Cet article évalue les effets sur la sécurité et le fonctionnement d’utiliser des voies de contournement pour les cyclistes aux carrefours giratoires comme moyen d’augmenter leur sécurité. L’article recommande également la pleine utilisation de signaux de circulation pour piétons, proposée par d’autres études, en les incorporant aux voies de contournement proposées pour les cyclistes. Un processus d’évaluation des avantages pour la sécurité et des coûts des voies de contournement proposées est fourni pour aider les décideurs à déterminer le besoin de tels carrefours. Le processus d’évaluation est illustré par un exemple. [ABSTRACT FROM AUTHOR]

The paper presents the results and conclusions of dynamic load tests that were conducted on a highway bridge over the Gimån River in Sweden made of Super Cor corrugated steel plates (CSP), the first bridge of this type in Scandinavia. The critical speed magnitudes, dynamic coefficients, velocity vibration, and vibration frequency are determined in the paper. Conclusions drawn from the tests can be most helpful in the assessment of the behaviour of this type of corrugated plate - soil bridge. In consideration of the application of this type of structure in the case of small-to-medium span bridges, the conclusions from this research cannot yet be generalized to all types of such solutions. The application details with respect to all types of such bridge structures would require additional analysis (field and model tests and calculations) on the other types of soil-steel bridges. [ABSTRACT FROM AUTHOR]

This paper presents the results of an assessment performed on the empirical model used in level 3 input of the proposed mechanistic-empirical pavement design guide (MEPDG) developed under the National Cooperative Highway Research Program (NCHRP) project 1-37A. The empirical formula estimates the stiffness (dynamic modulus) of asphalt concrete mixes used in paving roads. The assessment revealed that analytically estimated dynamic modulus differs substantially from the actual value determined in the laboratory. Errors are high at elevated service temperatures and for mixes prepared with engineered binders. An alternative approach is presented in this paper based on the use of generic modulus values. Generic asphalt concrete dynamic modulus values were generated from tests performed on typical Marshall and SuperPave mixes. Results were compiled in a database (material library) to provide users of the MEPDG with estimates of the dynamic modulus that will yield more accurate predictions of performance until dynamic modulus laboratory testing capabilities are established locally. [ABSTRACT FROM AUTHOR]

This paper investigates a relatively new engineering service that is being introduced in Ontario: subsurface utility engineering (SUE). This service combines civil engineering, surveying, geophysics, and nondestructive excavation for the accurate mapping of underground utilities. This paper presents the results of a one-year study that investigated the use of SUE on large infrastructure projects in Ontario. The study involved performing a detailed cost analysis of nine successful SUE projects, four of which are presented in this paper. Potential cost savings were estimated for each case study and all indicated that SUE has a positive return on investment. In addition, two industry-wide surveys were conducted to investigate the effects of inaccurate utility information on projects. Results indicate that inaccurate utility information has a significant impact on project cost, schedule, and damage to existing utilities. Using the results of the case study analysis and the survey, a generic cost model for SUE was developed that relates project specific characteristics to costs that could be incurred because of inaccurate utility information. This investigation provides valuable insight to the application of a relatively new process in Canada following successful results in the United States. [ABSTRACT FROM AUTHOR]

The brick–mortar interaction is important in the mechanical behaviour of masonry. It affects the load transfer considerably, as shown by detailed deformation measurements taken using electronic speckle pattern interferometry (ESPI), a laser speckle interference technique. A companion paper [Canadian Journal of Civil Engineering, 34(11), 1475 (2007)] by the authors of this paper argues that the joint is the only part of contemporary masonry significantly affected by manual action, which is why large material variations appear at the brick–mortar interface. To evaluate this phenomenon, ESPI measurements were performed and compared with accompanying linear variable differential transformer (LVDT) results. The behaviour of specimens loaded with various eccentricities was relatively soft in the brick–mortar interface area when compared with the behaviour shown in the surrounding stiff brick and mortar. The brick–mortar interface was characterized by a central part surrounded by fissures. Most of the load was transmitted in the central part. Because of this, the axial strain curve over the width of the specimens was U-shaped for concentrically loaded specimens (i.e., those with zero eccentricity). Over the height of the two-brick one-joint specimen, a smooth, B-shaped lateral strain curve was observed, in which the largest strains were found in the bricks. [ABSTRACT FROM AUTHOR]

Shape memory alloys (SMAs) are special materials with a substantial potential for various civil engineering applications. The novelty of such materials lies in their ability to undergo large deformations and return to their undeformed shape through stress removal (superelasticity) or heating (shape-memory effect). In particular, SMAs have distinct thermomechanical properties, including superelasticity, shape-memory effect, and hysteretic damping. These properties could be effectively utilized to substantially enhance the safety of various structures. Although the high cost of SMAs is still limiting their use, research investigating their production and processing is expected to make it more cost-competitive. Thus, it is expected that SMAs will emerge as an essential material in the construction industry. This paper examines the fundamental characteristics of SMAs, the constitutive material models of SMAs, and the factors influencing the engineering properties of SMAs. Some of the potential applications of SMAs are discussed, including the reinforcement and repair of structural elements, prestress applications, and the development of kernel components for seismic devices such as dampers and isolators. The paper synthesizes existing information on the properties of SMAs, presents it in concise and useful tables, and explains different alternatives for the application of SMAs, which should motivate researchers and practicing engineers to extend the use of SMAs in novel and emerging applications. [ABSTRACT FROM AUTHOR]

The precast concrete pipe industry is in continuous pursuit to add value to its products to strengthen its market competitiveness against other pipe products. The research reported in this paper aimed at developing a new class of precast concrete pipes that will provide added value to the final user in comparison with existing products. The technology developed by the authors consists of lenses of a porous material that are used to create "conduits" within the wall of a precast concrete pipe, which are continuous across adjacent segments. These conduits can accommodate telecommunication lines (i.e., fibre optics) and other small diameter utilities. The concrete pipe provides protection for the smaller conduits while conserving underground right-of-way space. This paper describes the results of an extensive numerical study undertaken to evaluate the technical viability of the proposed conduit system. [ABSTRACT FROM AUTHOR]

Owing to climate warming trends, there has been an increasing interest in recent years in the accelerating creep of rock glaciers and frozen slopes. In the field of glaciology, the creep of glaciers has been extensively studied, observed, and analyzed for more than 100 years. Many valuable and detailed theoretical models have been proposed through the years for simulating the creep behavior of glaciers. This synthesis paper has no intention of proposing another one. Its purpose is only to supply to these models a potential geotechnical background, borrowed from the connected fields of frozen ground mechanics, rock mechanics, and the mechanics of mixtures. In particular, this paper attempts to extend some known models of mechanical behavior of unfrozen soil and rock masses to masses containing ice and to apply these models to large-scale creep of ice–rock mixtures and ice–rock interface problems under variable temperature and stress conditions. [ABSTRACT FROM AUTHOR]

In a companion paper (R.E. Erkmen and M. Mohareb. 2006. Canadian Journal of Civil Engineering, 33: 421–439.), three finite elements based on the Vlasov thin-walled beam theory were formulated using a nonorthogonal coordinate system. Although the associated derivations are more elaborate than in more conventional solutions based on orthogonal coordinates, the new elements offer more modelling capabilities and flexibility in modelling structural steel members, a feature that is illustrated in this paper. In this context, the current paper presents four details in steel construction that were conveniently modelled within the new solution scheme. The applications involve thin-walled members with coped flanges, rectangular holes reinforced with longitudinal stiffeners, and eccentric supports. Comparisons with established shell finite element models using ABAQUS suggest the validity of the new solution. [ABSTRACT FROM AUTHOR]

As the industrial construction sector in Alberta faces a period of megaprojects, cost and schedule overruns are becoming a major concern for both owners and contractors. One factor that often contributes significantly to these overruns is construction field rework. Despite the significance of rework, there are few industry standards available for defining, quantifying, and classifying field rework. This paper presents the results of a pilot study, conducted on one such megaproject, that attempts to develop a standard definition of construction field rework, a standard index for its quantification, and an approach for classifying the causes that lead to field rework so that they can be remedied. The data collection methodology developed is discussed, and the findings that arise from this methodology for the case study are presented. The main conclusion of this paper is that the proposed methodology is quite effective in its thorough analysis and treatment of the field rework issue, and it can be used as a first step towards an industry Best Practice for measuring and classifying construction field rework. It can now be used on subsequent projects over time to collect a sufficient dataset, from which the construction industry can develop industry standards and statistics on construction field rework. [ABSTRACT FROM AUTHOR]

Severe water hammer following pump shutdown was suspected to be the cause of pipe displacement at a pump station in Saguenay, Quebec, because it appeared that insufficient surge protection was installed on the force main. To confirm this assertion and prevent further pipe displacement, data logging of a field test of the sewage pump station undergoing power failure was conducted in combination with the development of a water-hammer computer model for the design of additional surge protection measures. This paper describes the results of field testing, both before and after the installation of additional surge protection, and the calibration of a method of characteristics water-hammer model that accounts for vaporous cavitation and unsteady friction effects within the force main. Good agreement is shown between measured and computed pressure head histories at the pump station and at a vacuum relief valve following loss of power to a pump. To the authors' knowledge, this paper presents one of the first applications of the unsteady friction model referenced in this paper to a real system. [ABSTRACT FROM AUTHOR]

There has been increasing interest in international construction since the late 1990s due to growing competition in global markets. A bibliometric analysis of international construction research is conducted to evaluate the trends and to map the productivity in the field. Using the Scopus database from 2003 to 2013; document type, research performance of leading journals and authors, geographic and institutional distribution of research is assessed. The core and sub topics of the literature is also analyzed to determine critical themes in international construction. Results reveal that (1) risk management, (2) measuring performance, (3) general strategy and (or) competitiveness, and (4) foreign market entry decision are the top four core themes in international construction research. The fluctuations in the number of papers in different subject categories reflect the new tendency in international construction debate, which emphasizes a shift from measuring performance themes to general strategy and (or) competitiveness and foreign market entry decision in international construction. [ABSTRACT FROM AUTHOR]

To identify and calibrate the finite element model for multi-story buildings, a simplifıed approach is being introduced in this paper; this methodology is based on interferometric imaging and encompasses spectral ratio (SR) method. Interferometric imaging provides a new set of seismic data free of coupling between structures to its subsurface and independent of the excitation of the building. The SR method, on the other hand, is the ratio of Fourier amplitude spectra of the roof-deconvolved records on two adjacent stories. The newly introduced methodology enables each story to be identified uniquely for its stiffness since the SR of a particular story is dependent only on the properties of itself and the stories above. [ABSTRACT FROM AUTHOR]

Engineering information delivery can be a source of inefficient communication of design, leading to construction rework and lower worker morale. Due to errors, omissions, and misinterpretations, there remains a great opportunity to improve the traditional documentation of engineering information that craft professionals use to complete their work. Historically, physical three dimensional (3D) models built by hand provided 3D physical representations of the project to assist in sequencing, visualization, and planning of critical construction activities. This practice has greatly diminished since the adoption of 3D computer-aided design (CAD) and building information modeling technologies. Recently, additive manufacturing (a.k.a. 3D printing) technologies have allowed for three dimensional printing of 3D CAD models. A cognitive experiment was established to measure the effectiveness of 2D drawings, a 3D computer model, and a 3D printed model in delivering engineering information to an end-user are scientifically measured. The 3D printed model outperformed the 2D drawings and 3D computer interface in productivity measures. This paper's primary contribution to the body of knowledge is identification of how different mediums of engineering information influence the performance of a simple task execution. [ABSTRACT FROM AUTHOR]

This paper demonstrates the implementation of a traffic simulation linked with instantaneous emissions modelling and is used to evaluate the effects of street closures and area-wide pedestrianization on vehicle-induced greenhouse gas emissions. The study is set in Montreal, Canada where traffic in a dense borough (8656 links) is simulated in a dynamic traffic assignment mode to generate second-by-second speed profiles along every link in the 7-8 AM period. Instantaneous speeds are then used to estimate link-level and intersection-level emissions. The traffic demand at the borough boundaries is simulated using a mesoscopic traffic assignment model developed for the Montreal metropolitan region (127 217 links). Street closures and area-wide pedestrianization schemes are modelled within the microscopic as well as the mesoscopic models to evaluate their effects on greenhouse gas emissions, both while accounting for changes in demand and under constant demand. In all cases, we observe an increase in borough-level greenhouse gas emissions compared to the base-case scenario indicating that such schemes do not lead to a reduction in emissions even when accounting for changes in demand. We also compare emissions calculated using the microscopic models (traffic and emissions) and those obtained from the mesoscopic assignment (traffic and average-speed emissions) and observe that the regional model is much less sensitive to local-level changes mostly due to the incapacity of simulating accelerations and decelerations and therefore underestimating the changes in borough-level emissions compared to the base-case scenario. This indicates the importance of adopting instantaneous emissions models for the evaluation of changes to street configuration. [ABSTRACT FROM AUTHOR]

Traffic assignment has traditionally been performed using aggregate static user equilibrium approaches for a single mode. These approaches are typically favoured over more complex dynamic multimodal micro and meso-simulated models. Investigations into dynamic multimodal assignment models have shown promise, prompting interest in the adoption of complex modelling structures. The development and operation of these complex models can still be problematic, highlighting the need for efficient approaches to allow practitioners to acquire and apply these models. This paper presents a method to modify existing static auto assignment networks for dynamic multimodal assignment. To complement this, a method, which improves the overall performance of the transit routing procedure used within many assignment models, is presented. These methods were tested using data from the Greater Toronto and Hamilton Area, and result in an assignment procedure with reasonable run time and results, suggesting potential for wide spread adoption of these approaches. [ABSTRACT FROM AUTHOR]

Parameters (factors and practices) influencing construction labour productivity are multi-faceted and project dependent. A proven measurement scheme and modeling approach to investigate the effect of parameters on construction labour productivity has not yet been developed. This study identifies key parameters influencing labour productivity using context-sensitive surveys that reveal contextual differences between key parameters. The study relies on data collected through 141 surveys administered to project management and trade respondents from six Canadian projects in either of two contexts: building and industrial. Analysis revealed the top parameters influencing labour productivity on building and industrial projects. Consensus between project management and trade level respondents regarding parameters' effects within and between contexts was evaluated using statistical analysis; results indicated some differences in perception. The methodology and findings from this paper are useful for identifying enablers of and barriers to better productivity, developing context-sensitive labour productivity models for use in analysis, and developing productivity improvement strategies. [ABSTRACT FROM AUTHOR]

Compressing project schedule using activity accelerating and overlapping requires that an intensive time-cost trade-off analysis be carried out, to determine costs and benefits for each day of compression. However, the cost elements and implications of compression techniques differ significantly, since activity accelerating imposes extra direct cost whereas activity overlapping adds a risk of changes and rework. Such a trade-off becomes even more complicated in capital projects comprised of a large number of schedule activities and relationships. The variety of combinations of accelerating and overlapping of different activities in these complex networks can offer numerous possibilities for compression with various costs and potential risks. The lack of a reliable analytical tool for performing a precise cost-benefit analysis causes this critical task to be performed in a subjective manner during the planning stage of projects. The purpose of this paper is to present an advanced method using a multi-objective evolutionary optimization tool seeking the optimum degree of accelerating and overlapping during the schedule compression process. This optimization technique would be beneficial in maximizing project benefits while meeting the intended target dates. [ABSTRACT FROM AUTHOR]

Given anticipated climate change and its inherent uncertainty, a pavement could be subjected to different climatic conditions over its life and might be inadequate to withstand future environmental stresses beyond those currently considered during pavement design. This paper incorporates climate change effects into the mechanistic-empirical (M-E) based pavement design to explore potential climate change and its uncertainty on pavement design and performance. Three important questions are addressed: (1) How does pavement performance deteriorate differently with climate change and its uncertainty? (2) What is the risk if climate change and its uncertainty are not considered in design? and (3) How do pavement designers respond and incorporate this change into M-E design ? Three test sites in the United States are examined and results demonstrate a robust and effective approach to integrate climate change into pavement design as an adaptation strategy. [ABSTRACT FROM AUTHOR]

Roundabouts are hastily spreading around the world, mainly because of their good safety performance, and several countries have recently updated their standards and guidelines. However, inconsistencies in design standards and practices are observed. In this paper, a critical review of the Australasian, EU, and US standards and guidelines is performed. As a result, key issues of the existing standards are identified, along with research areas to fill the knowledge gaps and recommendations for improvement in a case study, Italy. These recommendations are mainly based on the concepts of design flexibility and performance based design. Indeed, rigid standards, which do not really take into account safety and operational consequences of the design decisions and the need to balance opposing demands, might produce undesirable outcomes. [ABSTRACT FROM AUTHOR]

Much of North America's critical municipal right-of-way (ROW) infrastructure is facing a severe deficit in planned maintenance, rehabilitation, and renewal spending. An optimized holistic approach for capital improvement planning allows for the consideration of contiguity savings and efficiencies through the synchronization of rehabilitation and renewal projects for collocated segments from different ROW infrastructure component systems. This paper presents the results of the application of a holistic methodology to a small ROW network made up of segments of varying condition and criticality. This methodology was developed utilizing an evolutionary genetic algorithm to optimize a five-year capital improvement plan. The results from the application of the holistic model to an existing ROW network indicate that it is successful in achieving savings through synchronization and in providing superior maintenance, rehabilitation, and renewal plans when compared to the traditional paradigm where independent plans are created for road, sewer, and water utilities. [ABSTRACT FROM AUTHOR]

In the analysis of vibration of footbridges in vertical direction, for crowd situations, there is evidence in the literature that the whole effect of pedestrian action is not well modeled when applying current force-only models to represent such an action. In these models, the action of each pedestrian is represented by a pulsating force applied on the structure. In this paper, a crowd load model is proposed for sparse and dense crowds (with densities up to around 1.0 pedestrian/m2) in which biodynamic models are added to represent the whole action of pedestrians. The focus of the investigation is on vibration effects in vertical direction. Comparisons with measurements on a prototype footbridge were carried out and made it possible to identify differences in the structural response when applying force-only and force-biodynamic models to represent the pedestrian action. The latter (proposed) model resulted in a better agreement with the measurements. [ABSTRACT FROM AUTHOR]

This paper deals with the design of steel plate elements of rectangular industrial ducts. Because of the practical aspect ratios and the stiffener arrangements, such a plate element is often treated as a long plate (one way slab), fixed supported at the edges and subjected to transverse pressure. The design pressure and the deflection limit determine the plate thickness and the stiffener spacing. Current design practice considers the geometrical nonlinearity, however, uses the strength criterion of first yield. This investigation postulates that consideration of partial yielding of the plate may result in an economical design option, while meeting the serviceability criterion. The study is based on nonlinear finite element analyses of long plates subjected to increasing transverse pressure. Dimensionless parameters that characterize the behavior of such plates were identified and varied in a parametric study. Based on these analyses, design equations have been established for plate thickness and for stiffener spacing corresponding to three different scenarios namely; 0%, 16.5%, and 33% of through thickness partial yielding of the plate. Results show that allowing for 16.5% yielding results in 50% increase in stiffener spacing, at the expense of about 40% increase in deflections. Partially yielding plates can satisfy the serviceability limits states and can lead to economical stiffened plate systems for large rectangular industrial ducts. [ABSTRACT FROM AUTHOR]

Schedule compression is an attempt to reduce project durations for early delivery, or to catch up on occurred delays. This is usually performed using 'crashing', 'overlapping' and 'substitution' of activities. 'Crashing' is shortening task duration by adding more resource hours. 'Substitution' is changing the method or tool by which the activity is performed. 'Overlapping' is performing sequential activities in parallel. Few studies can be found in the literature that compare costs and benefits of each technique and recommend the optimum combination of these techniques in project schedules. In fact, the implications of each technique are inherently different since crashing and substitution impose extra cost whereas overlapping adds the risk of changes and rework. Therefore, it is a challenge to develop a reliable analytical tool for performing time-cost trade-offs using the three methods. There are also few studies in the literature to propose a practical method for performing schedule compression by combining these techniques. The purpose of this paper is to discuss these schedule compression techniques in detail, and present and validate a heuristic method to perform the combination of crashing, overlapping and substitution in a project schedule, to reach the maximum benefit while meeting the project target dates. [ABSTRACT FROM AUTHOR]

This paper examines the effect of tire footprint and contact stress distribution under various combinations of tire pressures and tire loads on the pavement response through 3-D finite element static analysis with linear elastic material model. Analyzed footprints include a field-measured footprint and two cases of simplified ones. Our results indicate that factors including tire load, the distribution of contact stress, and the shape of footprint will affect the tensile strains at the bottom of the asphalt concrete layer as well as the compressive strains on the top of the subgrade. However, the compressive strains on the top of the subgrade are more sensitive to tire load than the shape of footprint. The research demonstrated that pavement response analysis could be carried out using field-measured footprints instead of the simplified approximations. Reduced tire pressure was effective in reducing the tensile strains at the bottom of asphalt concrete layer, but did not decrease significantly the compressive strains at the top of the subgrade. [ABSTRACT FROM AUTHOR]

In semi-arid and arid regions, civil engineers may be required to plan measures, such as sand fences, to control sand movement affecting developed areas or transportation corridors. In this paper, considering the desertification process for the Minqin Oasis in Gansu Province, China, the design of sand fences and overall sand control strategies to lessen the rate of desertification are discussed. A sand transport model called MOSAND was developed to predict the sand transport rate for the Minqin Oasis. The model was based on a bed load transport (creep and saltation) equation and a logarithmic velocity profile for the wind. Using the measured wind data for the Minqin area, a monthly average sand transport rate was calculated that was used to determine an effective life span of a 3 m high sand fence. Sand fences in conjunction with straw checkerboard sand barriers are recommended to control sand drifts into the Minqin Oasis. [ABSTRACT FROM AUTHOR]

There have been significant changes in undergraduate civil engineering curricula in the last two decades. Key issues for university curriculum committees are selection and transference of appropriate skills and attributes for students to succeed in the industry. Despite significant changes occurring in teaching theories, civil engineering education still relies heavily on deductive instruction. Case-based teaching is one of the most widespread forms of inductive learning and this paper describes the differences between two of the most familiar types: 'case-histories' and 'case-studies'. These methods are presented using the Kansas City Hyatt Regency walkway collapse as an exemplar. The benefits of using this approach are improved retention of knowledge, better reasoning and analytical skills, development of higher-order skills, greater ability to identify relevant issues and recognize multiple perspectives, higher motivation and awareness of non-technical issues. Many of these outcomes are part of the expected attributes of civil engineers outlined by professional bodies. [ABSTRACT FROM AUTHOR]

The management and disposal of tailings is a major technical challenge for the mining industry as well as an environmental concern in many countries. Finding alternative recycling methods of tailings as construction materials in mining operations or mine sites has become a great challenge for the mining and civil engineering community. A promising technology with alternative usage of tailings as construction and support materials in mine sites is tailings shotcrete (TSC), a mixture of fine tailings, high cement content, and water. However, the understanding of the strength development and durability of TSCs is limited. Hence, this paper presents the results of experimental investigations for the strength development and sorptivity of TSCs under various chemical (sulphate), thermal or thermochemical loading conditions. Several TSC samples with different sulphate contents, cured at different temperatures (2 °C to 50 °C) and different times (1 to 120 d) are tested with regards to their strength, sorptivity, and microstructural properties. Valuable results are obtained with regards to the strength and durability of TSCs. The results also show that the curing temperature, initial sulphate content of TSCs and their coupling have a significant effect on the strength and sorptivity of TSCs. [ABSTRACT FROM AUTHOR]

During recent years, risk analysis has been introduced into infrastructure engineering, and has greatly improved the design, construction, and operation. In this paper, we study the risk of dams in the perspective of clustering analysis. Fuzzy c-means clustering (FCM) is widely used in many fields since it is simple and fast. However the result of FCM technique is sensitive to the initialization of clustering centres and is easily trapped into local optima. To improve the performance of FCM, an artificial bee colony algorithm (ABC) with FCM is proposed. By introducing ABC, the shortcomings of the original FCM method is overcome. The proposed clustering algorithm is demonstrated on a benchmark classification problem and two dam risk analysis problems. Results show that it is more accurate and robust than FCM, and it is an efficient tool for risk analysis of dams. [ABSTRACT FROM AUTHOR]

There are various methods offered in construction literature for determining the schedule impact resulting from delays and interruptions. Previous scheduling technique makes the assumption that the relationship between time and the number of units produced is linear. Accordingly, progress is assumed to be equally distributed along the activities' durations. Often this assumption does not reflect the real situation for the progress of construction activities. Some activities are naturally nonlinear and others exhibit nonlinear progress. To insure reality and reasonableness, delay analysis must allow for nonlinear production rates as well as linear production rates in the delayed activities. Therefore, there is a need for a delay analysis method that incorporates the varying rate of production for the delayed activities. This paper proposes a delay analysis method that can rationally apportion the concurrent delay with consideration of the nonlinear production rates of activities in construction projects. A simple case study has been implemented to demonstrate the accuracy and usefulness of the proposed delay analysis method. This research is useful for both researchers and practitioners for the case including the varying productivity due to delays and interruptions and allows transparent and rational analysis on concurrent delay to facilitate claim analysis. [ABSTRACT FROM AUTHOR]

The steel-free bridge deck system is an innovative solution in which the concrete deck slab is externally restrained by a series of steel straps. The ultimate strength characteristics of externally reinforced concrete bridge deck slabs were investigated in this paper. A 1/3 scale experimental model of a bridge with six girders was constructed for the study. This was the first known set of test results on a bridge model with more than four girders. A single point load, simulating the dual tire print of the CHBDC design truck, was applied at various locations on the deck and loading increased until punching failure occurred. The influence of different parameters including transverse diaphragms, proximity for the load to restraint straps, residual strength after strap removal, and simultaneous application of wheel loads in adjacent panels of the deck was tested to obtain a comprehensive understanding of the resistance of this deck system. The testing results confirmed that the interior panels of the deck have inherently higher punching resistance than the exterior panels. Most significantly, the study provided significant statistical data on the punching resistance of these deck slabs. Le système de tablier de pont sans acier est une solution novatrice dans laquelle la dalle de tablier en béton est retenue de manière externe par une série de sangles d'acier. Cet article examine les caractéristiques de résistance à la rupture des dalles de pont en tablier en béton armé renforcé de manière externe. Un modèle expérimental à l'échelle 1/3 d'un pont à six poutres a été construit pour cette étude. Les résultats des essais représentent le premier ensemble de résultats sur un modèle de pont ayant plus de quatre poutres. Une charge à un seul point, simulant l'empreinte de pneus jumelés du camion du Code canadien sur le calcul des ponts routiers, a été utilisée à divers endroits du tablier et la charge a été augmentée jusqu'à la rupture par poinçonnement. L'influence des divers paramètres, dont les diaphragmes transversaux, la proximité de la charge aux sangles de fixation, la résistance résiduelle après le retrait des sangles et l'application simultanée des charges de roues sur les panneaux adjacents du tablier ont été mis à l'épreuve afin d'obtenir une compréhension de l'ensemble de la résistance de ce système de tablier. Les résultats des essais confirment que les panneaux intérieurs du tablier possèdent essentiellement une résistance plus élevée contre le poinçonnement que les panneaux extérieurs. La conclusion la plus importante de l'étude a été de fournir des données statistiques importantes sur la résistance au poinçonnement de ces dalles de tablier. [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]

This paper provides a performance comparison of mechanistic laboratory and field rutting performance of four asphalt concrete mixes constructed in 1996 at a Strategic Highway Research Program SPS-9A test site located in Saskatchewan. The asphalt mixes included two Saskatchewan Type 70 Marshall mixes and two coarse graded Superpave™ mixes and employed 150-200A and 200-300A penetration grade asphalt cement binders. The triaxial frequency sweep characterization determined that the Superpave™ mix yielded improved mechanistic structural constitutive properties when compared to the Saskatchewan Type 70 mix. In addition, improved mechanistic structural properties were observed with the mixes employing 150-200A (PG 58-28) asphalt binder relative to the 200-300A (PG 52-34) asphalt binder, particularly the Saskatchewan Type 70 mix. The 10-year rutting performance of the Radisson SPS-9A test site was evaluated and the field rutting results concurred with the triaxial frequency sweep test results. The triaxial frequency sweep characterization employed in this study appears to adequately rank asphalt mixes with respect to field rutting performance. [ABSTRACT FROM AUTHOR]

This paper briefly summarizes the results of an experimental research project involving the testing of push-out specimens with channel shear connectors. The test program consisted of three series, each with 12 push-out specimens. In each series, six specimens had solid concrete slabs and the other six specimens had concrete slabs incorporating wide-ribbed metal deck with ribs parallel to the beam. The test parameters included the compressive strength of concrete and the length and web thickness of the channel shear connector. The test results showed that, for a given length of channel, the concrete strength dictates the failure mode. In specimens with higher strength concrete, failure was caused by the fracture of the channel web. Concrete crushing-splitting was the observed mode of failure in specimens with solid slabs when lower strength concrete was used. A concrete shear plane type of failure was observed in most of the specimens with metal deck slabs. The strengths of concrete used ranged from 21 MPa to a maximum of 35 MPa. [ABSTRACT FROM AUTHOR]

Some mix-design methods for self-compacting concrete (SCC) have been proposed since the 1990s, but these methods do not address all practical needs. This paper proposes a method that enables the composition of SCC to be designed for a given strength (in this study, from 10 to 50 MPa at age 1 day or from 30 to 70 MPa at age 28 days). In this method, the compressive strength of SCC at an early age is considered an important parameter to answer the needs of the precast industry. The proposed mix-design method is based on optimizing the packing density of aggregates and ensuring the necessary quantity of paste to fill the voids between aggregates and to provide good fluidity of the SCC. The compressive strength of SCC can be estimated according to the Bolomey formula, and the quantity of superplasticizer can be determined by the proposed method. [ABSTRACT FROM AUTHOR]

Critical static bridge loading scenarios are often expressed in terms of the number of vehicles that are present on the bridge at the time of occurrence of maximum lifetime load effect. For example, 1-truck, 2-truck, 3-truck, or 4-truck events usually govern the critical static loading cases in short and medium span bridges. However, the dynamic increment of load effect associated with these maximum static events may be assessed inaccurately if it is calculated in isolation of the rest of the traffic flow. In other words, a heavy vehicle preceding a critical loading case causes the bridge initial conditions of displacement and acceleration to be nonzero when the critical combination of traffic arrives on the bridge. Failure to consider these pre-existing vibrations will result in inaccurate estimation of dynamic amplification. This paper explores these dynamic effects and, using statistical analyses, outlines the relative importance of pre-existing vibrations in the assessment of total traffic load effects. [ABSTRACT FROM AUTHOR]