Trenching through existing asphalt pavements is a necessity for the installation and maintenance of critical utilities such as water and waste water services in most urban areas. The following will outline observed performance of a recent trench restoration program and provide strategies for decreasing wasted material and improving standards for trench restoration to minimize ground disturbance and material waste in urban residential areas. Drawing on historical information and collected data from pavement condition assessments performed on trenched pavement sections of different ages, the analysis looks to highlight performance characteristics from a lifecycle cost and environmental impact perspective, and relate these findings to pavement management strategies in low traffic, residential areas.
The use of database applications such as gINT to manage site borehole data in geotechnical consulting practice has become common. Such databases reduce the potential cost of future site investigations and allow valuable borehole information to be managed on a broader scale between multiple offices. Such data provides a valuable source for building lithology for 3D site models. When combined with topology, geotechnical shear strength laboratory data (such as shear box or triaxial data), and geotechnical design data an improved 3D conceptual model can be constructed. Such a constructed 3D site model forms a digital twin of the proposed geotechnical design for the real site and can be subjected to analytical simulations to determine if the proposed design meets specifications. Analysis such as slope stability, seepage, and stress/deformation can be performed on the conceptual model based on 2D profile slices or on the full 3D conceptual model. The movement to performing 3D stability analysis instead of the traditional 2D profile analysis has also heightened the need for fully formed 3D conceptual models of proposed geotechnical designs at sites. 3D slope stability analysis provides the benefit of improved rigor in the calculation of the factor of safety. Calculated 3D factors of safety are higher than 2D factors of safety and allow potential for cost savings on engineering designs that may be over-conservative. These new methodologies are providing advantages in the design of large engineered structures. The additional use of spatial sweeping slope stability analysis such as the multi-plane analysis (MPA) provide maps of factors of safety which further strengthen professional design. This paper presents an integrated approach to building lithology based on a gINT database and performing 3D spatial slope stability analysis. The new approach leverages the strength of existing borehole databases and provides more rigorous analysis to aid in the design of transportation structures such as embankments, retaining walls, and slopes adjacent to roadways.
This paper presents a state-of-the-practice of truck platooning technology, including policy, regulatory, and technological challenges and opportunities, and an envisioned timeframe for the implementation of the technology. Several demonstration projects on truck platooning conducted in the past have been highlighted, including the demonstration of a truck platooning system on September 14-15, 2017 on I-66 in Virginia, near Centerville. The I-66 demonstration was the most robust demonstration of truck platooning system considering that it was done on a highway in real traffic conditions, one of the busiest and most congested in the nation. Technological advances in automated vehicle technology, including truck platooning, are moving at a rapid pace. However, legislative and regulatory barriers need to be overcome for the widespread application and acceptance of this technology. Also, partnership among various stakeholders is crucial for the success of this technology.
Queen Street and Main Street in the Village of Alton, in the Town of Caledon, ON serves two distinctly different purposes. For locals and tourists, Main Street and Queen Street serve as the main thoroughfares in a picturesque, historic village. Lined with shops, restaurants, schools, churches, bed and breakfasts, spas and other small businesses; their sidewalks are filled with pedestrians at peak times. For trucks and others passing through, it is a Regional Road that is the fastest way to get to other larger Towns and Cities; and is a primary trucking route. Thus, competing uses provide a challenge in road design. This situation is not unique, but rather reflective of the typical road configuration in many parts of Ontario, and in Canada in general. The challenge presents itself to ensure pedestrian safety for towns in which their main thoroughfare also serves as a brief slowdown in what is otherwise a high-speed connector road. It has been demonstrated in similar scenarios that reducing regulatory speed limits does not achieve the desired level of speed reduction. Providing supplementary traffic calming features, such as splitter islands, narrowed lane widths, and streetscaping has been used effectively to further lower average speeds and improve pedestrian safety. Alton is one village that was identified by the Region of Peel as target for traffic calming improvements. At the same time, it was also identified in the Township of Caledon as one of the targets of the “Six Villages Community Improvement Plan”, a revitalization strategy to provide improvements in streetscaping, pedestrian connectivity, signage and other beautification in target villages. Through extensive design collaboration, stakeholder consultation, community outreach and project delivery, unique streetscaping features were developed that achieved the dual purpose of beautification with traffic calming. The most challenging project constraints included working within a narrow, 15 to 20- meter-wide right of way without acquiring property; environmental impacts; heritage buildings and geometric design considerations. The project includes a Municipal Class Environmental Assessment (Schedule B), bridge replacement in a Provincially Significant Wetland; vegetated face retaining walls; traffic calming islands with plantings and a gateway feature; decorative streetlighting and pedestrian lighting; new lay-by parking; decorative concrete; and rest areas. The first construction phase is scheduled to be completed in Spring of 2019. The second phase commenced in the Spring of 2019 and is scheduled to be completed in December of 2019.
As climate change continues to threaten pavement infrastructural performance across the World, the need for sustainable solutions for pavement adaptation cannot be overstated. In Canada, flooding is a prominent climate hazard common to most Canadian provinces and adaptation of pavements to this hazard is desired. Based on previous investigations, concrete pavements are recorded as sustainable, resilient to flood hazards, and proposed to be a good pre-flood strategy. However, design properties need to be given utmost consideration to provide required resilience. This paper takes a design approach to examine the resilience of Jointed Plain Concrete Pavement (JPCP) to flood by modelling the performance of matrices of typical PCC pavement designs in Canada under a Representative Concentration Pathway RCP of 4.5 W/m 2 future precipitation scenario. The AASHTO Pavement ME Design program is used to simulate and predict performance changes under flood scenarios taking the Provinces of Ontario and Manitoba as case studies. In the Ontario study, mean flood damage peaked at 5.99% and 2.39% for collector and arterial JPCP pavement. In the Manitoba study, a total of 27 pavement classes was developed based on typical traffic, slab thickness and subgrade parameters common to the province. From the analysis of all pavement design classes, minimum and maximum damage observed was 0.31% and 3.03% respectively. The performance of the pavement designs classes in terms of flood resilience, service life and cost feasibility were analyzed with respect to traffic and subgrade conditions. Generally, results provided insight into the resilience and adaptive capacity of rigid pavements to climate flood hazards under Canadian climate condition.
Steel buried bridges have been an integral part of the Canadian infrastructure for decades. In 2019, the largest steel buried bridge in the world, the Shammal Bridge Crossing, was built for a transportation application in Dubai, UAE utilizing the Ultra-Cor Corrugation. The structure had a span of 32.39 m and a rise of 9.039 m which led to a spot on the Guinness World of Records. The structure was instrumented with strain gauges and deflection prisms. The full-scale test results demonstrated that the performance of the structure is satisfactorily and meets exceeds the targeted demand to capacity ratio.
Truck loading is an important factor in pavement design and road asset preservation. In addition to load weight spectra, roads are often subjected to uneven axle loading, lateral lane position wander, variable tire pressures and variable tire types. An important consideration in determining load impact is how the load traction state is distributed within a single vehicle and the impact on road primary response profiles. This paper is a study of the structural effects on the pavement layers caused by uneven tire load tractions as compared to a non-uniformly distributed loading which is often assumed for pavement design, asset management and performance prediction purposes. Tire load distribution measurements were collected from sensors installed on traffic data collection sites. Based on the real world traffic stream data collected, the frequency of tires with low contact pressures was established. A nonlinear stress-dependent three-dimensional finite element analysis was performed on a typical rural road structure under various climatic field state conditions. Shear strain profiles were analyzed by various heavy truck loadings within the road structure. These findings show shear strain increases of up to 30 percent around the underinflated tire cases when compared to a uniformly distributed loading across all field state climatic conditions and traffic speeds. Based on these results, it is recommended load enforcement; pavement management and design of roads consider load distribution among tires within axle groupings, tire footprint distribution and lane distribution in addition to total axle group weights.
Bayview Avenue is a major north-south arterial corridor under the jurisdiction of The Regional Municipality of York (York Region). Located in the Town of Richmond Hill, Ontario, the lower segment of the project corridor contains a principal tributary of the Rouge River that is fed, at this location, through significant steady state groundwater upwellings from the Oak Ridges Moraine Aquifer directly below. The principal tributary and former road side ditches now all contain significant brook trout population and habitat. The watershed is managed by the Toronto and Region Conservation Authority and the brook trout habitat is managed by Fisheries and Oceans Canada. York Region and the Town of Richmond Hill are undergoing tremendous growth in population and employment. In response to this growth, the Bayview Corridor Project improves mobility for all corridor users including motorists, pedestrians, cyclists and fish, with an innovative design enhancing the environment. The design of the project included extensive consideration of artesian conditions resulting from the Oak Ridges Moraine Aquifer and resulting brook trout habitat which contributed to the overall duration and complexity of the project.
Mechanically Stabilized Earth (MSE) structures are retaining walls with compacted soil that is reinforced with inclusions consisting of horizontally placed elements. MSE walls reinforced with steel elements are classified as inextensible. In some applications, the steel reinforcing elements connect to a facing component. The type of soil reinforcing and the corresponding facing will depend on the structure application. This paper will discuss the challenges associated with the design of tiered MSE wall application. The paper will explain what a tiered MSE wall is and how global and compound stability are performed. Also, it will describe the roles and responsibilities of the Geotechnical Engineer and the MSE Engineer and how the roles can overlap becoming shared responsibilities and to manage them. To demonstrate, a recent successful example project will be used to demonstrate these issues. The selected project is the St. Jacques-Pullman Interchange project located in Montreal, Quebec. The owner is the ministère des Transports du Québec (MTQ).
Performance Graded Asphalt Binders (PGAB) are selected under the Superpave system to provide superior performance according to the climate in which the pavement will serve. Rutting and fatigue resistance are provided at selected reliability levels by meeting various physical properties at corresponding site-specific high and low design pavement temperatures. These design temperatures have been previously determined using climatic data from across North America within the LTPPBind V3.1 software, and more recently can be assessed using LTPPBind Online. The high and low design pavement temperature and performance grades were determined using three approaches: LTPPBind Online; LTPPBind V3.1 model with climate data captured through the Road Weather Information Systems (RWIS) network utilized by the Maritime Provinces; and, using direct measurements of pavement temperature obtained using the RWIS network. Differences in the results were compared to assess possible changes arising from climate change effects and to update pavement temperatures required for asphalt binder testing under AASHTO M332 (“Standard Specification for Performance-Graded Asphalt Binder Using Multiple Stress Creep Recovery (MSCR) Test”) specification. LTPPBind Online was discontinued in the study due to differences observed in computing certain climate statistics compared to LTPPBind V3.1 and hand calculations based on the reported equations contained within both versions of the software. An average increase in the calculated high temperature grade requirement of 2.89°C was observed between results based on RWIS air temperature data versus approximately 25 years of Environment Canada climate data used within LTPPBind V3.1. However, a linear bias was observed when comparing the RWIS air temperature and LTPPBind V3.1 results which may have influenced the outcome. Pavement design temperatures developed using direct measurements at the RWIS stations were found to exhibit similar spatial variations to those developed using LTPPBind 3.1, but appeared to exhibit slight increases in both the high and low design temperatures over time of 0.2 °C and 3.28 °C, respectively. It is unknown if these differences are due to climate change effects or differences between the LTTPBind predictive model and direct temperature measurements. Design pavement temperatures should be evaluated annually using a shorter 10-year window of climate data to monitor the rate of change and predictions of future performance grade requirements.
Accurate acquisition of aggregate characteristics (shape, size and spatial position) is the basis for in-depth analysis of asphalt mixture grading, uniformity and surface texture. This paper proposes a modified recognition algorithm for loose asphalt mixtures based on digital image processing. The process first converts a True Color RGB image into a binary image during pre-processing. Then a Euclidean distance transform of the binary image is performed, which can be used to get the regional maximum value. In order to avoid over-segmentation caused by the traditional watershed algorithm, a modified watershed segmentation algorithm based on the extended-maxima transform is developed, effectively limiting the number of regional maximums to a reasonable range. Then the watershed ridge lines are superimposed on the original image. Hence, the aggregates are separated correctly, especially touching particles. Seventy images of untreated aggregates consisting of different particle sizes were tested. The results showed that the improved method could effectively segment the particles with accuracy as high as 98%. Finally, the proven methods are programmed and used to identify the particles of loose asphalt mixture. The results showed that the physical information of the loose asphalt mixture aggregates could be adequately recognized, and the accuracy is 96%, which is a solid foundation for the subsequent in-depth research.
Although sidewalks and trails act as the foundation infrastructure for active modes, they are often secondary concerns to many municipalities. With limited budgets and resources, there is often greater emphasis in focusing investment towards primary infrastructure (such as roadways and bridges), which are typically backed by greater operational information and condition investigations that are used justify the use of public funds. While the focus on main infrastructure is justified, this often leaves very little funding or consideration for secondary infrastructure like sidewalks and trails. This issue of limited funding for sidewalks and trails, combined with potential high public use yet limited background data, increases the risk of lawsuits from conditions like trip hazards. Such lawsuits can be quite costly to municipal agencies and detrimental to public perception of safety and mobility. These practices of minimum funding and high liability lead to an inconvenient truth - sidewalks and trails carry a high level of liability and many agencies are not focusing on them enough. One reason for the omission in funding and priority is that municipalities struggle with how to approach condition rating their sidewalk and trail networks. There can even come a point where only condition rating the network is not enough. Simply put, this situation can place agencies in a position of having the data and being unable to use it effectively. To address these problems, the City of St. Albert set out to not only develop an acceptable condition rating system, but to also work closely with its GIS and IT departments on how to best represent it. This resulted in a network level condition rating which allows the city to have its sidewalk network represented in 10 m sections, all condition rated in a range of 1 to 5, 1 being “good condition”, 5 being “poor condition”. This system has allowed the City to better coordinate capital funding to ensure that as much work is accomplished in approved capital programming while being responsible with tax funds in complete transparency.
Shoreline erosion and relative sea level rise are increasing the risk of flooding and storm damage to Highway 2 as it approaches the Town of Souris. Climate change with the associated rising sea levels, reduced ice cover and changing storm patterns threaten to exacerbate this problem. In order to improve protection of the PEI portion of the Trans-Canada Highway (Hwy 2), PEI Transportation Infrastructure and Energy (PEI-TIE) worked with Coldwater Consulting Ltd. to develop and construct a two-part shore protection scheme that combined hard protection for the highway infrastructure with beach restoration works that would improve the resilience of the beach and dune system: 1. A timber/piled seawall was constructed parallel to Highway 2. This seawall allows for protection of the highway, while also extending the existing promenade along the top of the seawall. The wall was set back from the beach face to allow adequate space for beach restoration; 2. Dune restoration and shoreline stabilization works were undertaken to restore and strengthen the existing sand beach – dune system. The beach restoration works included the construction of two inter-tidal reefs. This is the first time that inter-tidal reefs have been used on the Island. An example of 'building with nature', the sandstone reef structures provide two primary functions: wave attenuation, dampening the effects of storm waves on the beach area and highway infrastructure; and, creating an area of calmer water on the landward side of the reefs where sand that is moving along the shore area will slow down and deposit and, over time, accumulate and cause the beach to grow / extend offshore towards the reefs.
More than 6.5 million tonnes of asphalt is used annually in the maintenance and construction of new roads in Ontario municipalities. The use of reclaimed asphalt pavement (RAP) in road construction has been proven to provide sustainable structures without affecting the integrity of virgin materials. Currently, in Ontario, only two-thirds of municipalities allow the use of RAP in the mix design of asphalt pavements, and most of those municipalities only use it in the base course layer. Promoting such sustainable approaches to infrastructure would lead to cost-effective spending on infrastructure, sustaining resources of virgin materials and would also result in limiting greenhouse gas emissions through reducing asphalt consumption and through utilizing locally available recycled materials. This paper aims to provide quantification of the current amount of RAP available in the province of Ontario, as well as provide trends of RAP consumption. An environmental scan of the province was conducted to obtain a database of RAP stockpile locations across Ontario. Volume measurements were conducted by using Google Earth Pro Software package. Additional calculations were conducted to estimate tonnage quantities of RAP. The RAP inventory and the trends of RAP consumption resulted from this study would help in the decision making for steering the infrastructure towards more sustainable use of available materials.
La Ville de Montréal (la Ville) possède et gère plus de 2 500 feux de circulation sur son territoire. Plusieurs systèmes simples et complexes sont actuellement en place actuellement afin de gérer dynamiquement les feux de circulation, par exemple des systèmes adaptatifs. Évidemment, les systèmes complexes sont performants, mais également plus dispendieux à l’achat, au déploiement et en frais de maintenance. Ils nécessitent habituellement de déployer des équipements de détection à toutes les approches d’une intersection à contrôler. Notre vision est de créer un système simplifié, moins coûteux et flexible. Ce système sera peut-être légèrement moins performant au départ, mais offrira plus de potentiel d’amélioration. L’approche de la Ville est d’utiliser une technique de gestion des feux de circulation existante, en l’occurrence le TRP (Traffic Responsive Plan), bien maîtrisée et d’y ajouter un volet de prédiction. En utilisant la prédiction des débits de circulation, on prévoit que les feux de circulation soient proactifs sur le trafic plutôt qu’en réaction à ce dernier. La technique de prédiction présentement utilisée est l’apprentissage machine et s’alimente à partir d’un flux de données temps-réel Internet des Objets (IdO) issu de plusieurs détecteurs véhiculaires. La technique d’apprentissage machine utilisée est eXtreme Gradient Boosting, XGBoost, (Chen & Guestrin, 2016) et sa performance est évaluée à l’aide de l’erreur moyenne absolue (mean absolute error, MAE). Nous présenterons les différentes phases du projet, l’étape à laquelle nous sommes rendus, ainsi que les différentes équipes impliquées à chaque étape. Sera aussi démontré le potentiel d’amélioration qu’apporte l’apprentissage machine en comparaison des autres techniques de gestion des feux de circulation.
In cold regions such as Canada, pavement structures are subject to extremely low air temperatures and seasonal freeze-thaw cycles over the life cycle of the roadway, resulting in pavement distress, deterioration, and decreased service life. Each year, billions of dollars are spent in Canada on rehabilitation and new construction of asphalt pavements. Hence, prevention of premature failure has become of prime strategic importance for road owners. Fibers have already been used to reinforce paving materials for many decades in various parts of the world. Polymer fibers have high tensile strength relative to asphalt mixtures, and thus, have the potential to improve the cohesive and tensile strength of bituminous mixes and prevent crack propagation in the resulting composite. The most commonly used polymer fibers are polyester, polypropylene, aramid, and various combinations of these. There has, however, been less attention to the incorporation of fibers in asphalt mixes to improve resistance to thermal cracking, an application that would prove extremely beneficial for road construction in cold climates. The objective of this research is to evaluate the effectiveness of adding polymer fibers to hot mix asphalt to increase its resistance to thermal cracking. For this purpose, three different types of polymer fibers including aramids, polyethylene terephthalate (PET) and polyacrylonitrile (PAN), in different sizes, were added to conventional hot asphalt mixes. The resulting samples were compacted in the laboratory and their mechanical properties were compared to conventional hot mix asphalt.
With rapid growth and development of urban cities, rural areas have become the primary location for industrial plants. Depending on the type of facility, major components may be fabricated at a facility far from the location of the industrial plant. The size and weight of these components during transport can significantly exceed typical roadway load limits. The secure and successful transport of the superheavy loads from the fabrication plant to the final location becomes a challenging endeavor. There have been multiple research attempts to develop structural response models to predict pavement damage from superheavy loads. This paper is an update to the 2016 TAC paper “Modelling Pavement Response to Superheavy Load Movement” in which the outcome of several studies of superheavy load moves planned for the spring and winter months was discussed. This paper expands the research on the transport of a super heavy load in winter. The transport of a Splitter from the Dacro Industries Inc. facility in Edmonton to the Inter Pipeline Propylene plant north of Scotford, Alberta was the heaviest-ever load on Alberta roads. The transport vehicle for the winter move comprised a double inter-combi trailer with a gross vehicle weight of approximately 1.5 million kilograms. This vehicle had two 24 axle line trailers with 1.5 m axle spacing. Due to the sophisticated nature of the project, and various shortcomings highlighted with previous research methods, non-linear dynamic finite element modelling (FEM) was used to determine the pavement layer stresses and strains when subjected to superheavy load moves. To facilitate the move, several trials were completed with various scenarios. The move was successfully completed on the first week of January 2019. This paper will summarize the methodology and results of various scenarios predicted and the pavement inspection result prior to and after the move.
Tack coats are thin applications of emulsified asphalt used to create an adhesive bond between asphalt layers, to allow for the creation of a monolithic structure as per pavement design requirements. The result is a “non-slip” structure comprised of fully-bonded pavement layers to distribute the traffic loads at an acceptable stress level to the subgrade. However, fully-bonded conditions may not necessarily be achieved during the pavement construction if the application rates are not optimized. This paper presents results of a 2018 field study conducted on a four-lane highway in the Province of New Brunswick. For this study, the maximum bond strength was determined by considering four tack coat spray rates in combination with two surface textures: milled surface and new asphalt mix. A section with no tack coat was also evaluated as a control section. Cores were subsequently collected following construction operations in order to determine the initial interlayer shear bond strength. An innovative “non-tracking” emulsion was used for this study as a tack coat for all the sections. Findings from this project will be used to provide recommendations and guidelines for optimum application rate, as well as construction best practices. This paper provides a summary of the field experiment and observations.
Nares River Bridge is located at km 105.2 on the Klondike Highway #2, Yukon, in the village of Carcross, and approximately 75 km south of Whitehorse. The existing Nares River Bridge was constructed in 1970 and consists of 17 trestle spans with a total span of 129 m. The bridge carries two traffic lanes of Klondike Highway #2 across the Nares River. The superstructure is comprised of longitudinal timber wearing planks on a transverse timber sub-deck. The substructure consists of steel trestles comprised of steel cap beams, pipe piles, and bracing. The ballast wall at the abutments uses staggered wooden planks. The southern part of the Klondike Highway is an important link in the Yukon highway system because it serves the mining, international commerce and tourism industries. The bridge is a vital piece of infrastructure because there is no other reasonable detour route for the transportation of goods and services between Yukon and the Skagway port. While the bridge remains safe for usage today, heavy haul loads are no longer permitted on account of compromised bridge capacity. Because of the importance of Nares River Bridge, inadequacy of the existing structure, and asset depreciation, the bridge has been prioritized for replacement. Highways and Public Works (HPW) is currently replacing Nares River Bridge at Carcross with a budget of $15 millions for the project over two years. The Nares River Bridge replacement project will provide Yukoners with a bigger and better bridge as part of Yukon’s highway network. Not only will this new asset ensure the South Klondike Highway is ready and able to meet future traffic demands and support the community of Carcross and the Carcross/Tagish First Nation, the project is also providing economic opportunities for Yukoners. For the first time on an infrastructure project of this nature, the Government of Yukon procurement process included a First Nation participation plan intended to address employment and training for Carcross/Tagish First Nation citizens and Carcross/Tagish First Nation firms. Many challenges were faced during the planning, consultation and procurement stages.
Connected vehicle technology consists of Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) communication, collectively referred to as V2X. This enables vehicles and infrastructure to exchange safety related information to enable smarter, safer roads. If driver alerts are raised or automated action is taken as a result of these messages, it is critical that messages are trustworthy and reliable. To this end, the Security Credential Management System (SCMS) has been proposed to provide authentication and authorization of V2X messages without compromising individual privacy. A critical aspect of this system is the ability to identify and remove misbehaving devices from the network. This paper provides an overview the SCMS, proposed approaches to misbehavior management (or lack thereof), and some of the difficulties the SCMS is likely to encounter as it is more widely deployed.