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An important component of any highway design project is the explicit evaluation of safety, leading to the quantification of the safety impacts resulting from changes in highway design parameters and the safety associated with the level of design consistency. Quantification of these safety impacts supports the design process by allowing decision makers the opportunity to analyse the safety benefits in relation to the cost of the highway improvement. This trade-off analysis allows for the justification of highway infrastructure investment. The ability to accurately quantify safety impacts is achieved by using evaluation tools such as collision prediction models, collision modification factors, and measures of design consistency. Although described and available in the safety engineering literature for years, these tools are now becoming widely accepted, since their use responds to the need to quantify safety. This is in sharp contrast to many traditional highway safety assessments, which often relied solely on expert opinion and often failed to adequately support difficult design decisions. Realizing the value of quantifying the safety impacts associated with design decisions, the British Columbia Ministry of Transportation tested an explicit safety evaluation approach for a new design of a section of the scenic Sea to Sky Highway, located between Vancouver and Whistler, in southern British Columbia, Canada. This paper describes the study, illustrating the benefits of this approach for the design process. The paper also offers some improvement over existing safety evaluation techniques. [ABSTRACT FROM AUTHOR]

To minimize disruptions of economic and social activities on the ground surface in urban areas, trenchless techniques such as pipe bursting are often considered for underground pipeline construction, rehabilitation, and renewal of existing utility services. Pipe bursting, however, inevitably induces outward displacements of surrounding soil, and subsequently leads to potential damages to adjacent structures and utilities. This paper carries out finite element (FE) analyses to investigate effects of the static pipe bursting-induced ground displacements on adjacent pipelines. In total 760 FE parametric studies are performed to encompass various combinations of ground settlement profiles, pipe dimensions, material properties, and soil properties that are typical of utility pipelines and pipe bursting in urban areas. The FE parametric results are summarized in a dimensionless plot of relative pipe-soil stiffness versus ratio of maximum pipe curvature to maximum ground curvature, which can be used to directly estimate the maximum pipe bending strain and (or) directly evaluate pipeline responses to adjacent pipe bursting. A worked example is provided to illustrate usage of the dimensionless plot. It is further found that the pipe-soil interaction is similar for pipe bursting and tunneling, and the effects of both pipe bursting and tunneling on adjacent pipelines can be assessed using a unified dimensionless plot. Effects of the intersection angle between the pipe bursting centerline and adjacent pipeline are explored. The pipe responses are shown to be underestimated or unconservative when only the perpendicular case is considered in the analysis. [ABSTRACT FROM AUTHOR]

A likely result of changes in rock stresses due to progressing mining is an increased number of compressive stress-induced failures. This paper presents the results from numerical analysis and observations of stress-induced fallouts in footwall drifts in the Kiirunavaara underground mine. A brittle-plastic 'cohesion-softening friction-hardening' (CSFH) material model was used for simulating brittle fallouts. To account for mining-induced stress changes, the local model stress boundary conditions were extracted from a global model. The rock mass properties were based on field observations in the footwall drifts as well as on results from laboratory testing. A multi-stage analysis was carried out to gradually change the stresses to simulate mining progress. A parametric study was conducted in which strength properties, location, and shape of the footwall drift were varied. Yielded elements and maximum shear strain were used as damage and fallout indicators. The modelling results were sensitive to the shape of the drift. The location of the predicted fallouts was in good agreement with the location of observed fallouts for the case in which the drift roof was simulated flatter than the theoretical cross section. The results indicate that the true shape of the drift is different from the planned one. [ABSTRACT FROM AUTHOR]

This paper evaluates the accuracy of three commonly used models that predict accidents on two-lane, rural, arterial highways. The retrospective evaluation compared model outputs with empirical collision results for a sample of highway sections in the Province of New Brunswick. The analysis determined historical accident rates, identified key predictive variables, and compared the observed results with estimates from each safety model. All three models were found to significantly overestimate accident frequencies on the highway sections under study. The model generally employed in New Brunswick, MicroBENCOST, was found to yield the highest errors in estimated collisions. These findings suggest that the benefits from accident reduction are generally overestimated on highway improvement projects analyzed with these accident prediction models. Cet article évalue la précision de trois modèles couramment utilisés pour la prédiction d'accidents sur les autoroutes à deux voies; rurales et les avenues. L’évaluation rétrospective à comparé les résultats des modèles aux résultats empirique de collision pour un échantillon de sections d'autoroutes dans la province du Nouveau-Brunswick. L’analyse a permis de déterminer le taux historique d'accidents, a identifié les principales variables prédictives et à comparé les résultats observés aux estimations de chaque modèle de sécurité. Il a été trouvé que les trois modèles sur-estiment significativement les fréquences d’accidents sur les sections d’autoroutes étudiées. Il a été trouvé que le modèle généralement employé au Nouveau-Brunswick, MicroBENCOST, produit les erreurs les plus élevées pour l’estimation des collisions. Ces résultats suggèrent que les avantages dûs à la réduction des accidents sont généralement sur-estimés dans les projets d'amélioration des routes analysés avec ces modèles de prédiction des accidents. [ABSTRACT FROM AUTHOR]

Workspace conflicts are one of the important problems that can delay construction activities, reduce productivity, or cause accidents that threaten the safety of workers. Workspace planning is particularly important in the case of large infrastructure projects, such as bridge construction, and rehabilitation projects where equipment with complex workspace requirement is required. This paper aims to extend the previous research on workspace representation and analysis in the case of large infrastructure projects focusing on the following issues: (i) specific representation of equipment workspaces using composite shapes, (ii) semiautomatic generation and analysis of workspaces, and (iii) development of a prototype system that can generate workspaces and detect spatiotemporal conflicts in a three-dimensional environment. The computational aspects of the proposed approach are discussed and demonstrated through the development of a prototype system, which has been applied in a case study of the deck replacement of Jacques Cartier Bridge in Montréal. [ABSTRACT FROM AUTHOR]

This study quantifies the effects of accidents by defining one of the indirect costs, the productive time lost owing to accidents in utility trenching operations. The probability of accidents, estimated by fuzzy-logic-based analysis of the performance of the factors (training, supervision, and preplanning) affecting safety in utility trenching operations, was used to quantify, based on simulation analysis, the productivity loss due to process delays resulting from accidents during excavation and pipe installation. It was determined that the productivity loss resulting from accidents during excavation is greater than that resulting from accidents during pipe installation. During excavation, the "very poor" condition of preplanning is most critical to productivity loss due to accidents, whereas during pipe installation, the condition of training and supervision affects the productivity loss more than that of preplanning. This paper provides insights into the relationship between the condition of the safety factors and the possible productivity loss by concomitant probability of accidents to quantify the effects of the accidents. [ABSTRACT FROM AUTHOR]