244 research outputs found
Long-Term Maintenance Needs Planning
This research contributes to Kentucky’s knowledge base of long-term maintenance needs in two parts. Part 1 presents an estimate of the average revenue needed to maintain four categories of highway in the first fifteen years after each is built or resurfaced. Total maintenance costs per mile for four types of facilities in five AADT volume categories were estimated. The results suggest that Kentucky is not resurfacing all its roads in a timely manner. Part II presents background information on preventive maintenance programs in the states. A review of the states found two recurring themes. The first was the widespread adoption of two types of preventive measures: thin overlays and crack sealing. The second theme was the adoption of maintenance schedules to ensure timely maintenance. The report recommends the development of a routine pavement maintenance program with three elements: (1) more timely resurfacing, (2) scheduled inspections of drainage and ditching, and (3) crack sealing. It is also recommended that the Kentucky Transportation Cabinet adopt ASSHTO’s recommended performance criteria and targets for sub-drainage assets
KYTC Maintenance Field Operations Guide Supplement
The Kentucky Transportation Cabinet (KYTC) is tasked with managing an asset portfolio that includes over 27,500 miles of roadway and 9,000 bridges. Keeping these assets in sound condition demands significant effort from KYTC’s Division of Maintenance, which includes activities ranging from mowing and litter pickup to cleaning out culverts and performing emergency roadway work. Despite the immense responsibilities shouldered by Maintenance personnel, until this project the Cabinet’s 12 districts lacked a systematic method for capturing and recording maintenance activities. Through a series of workshops held in each KYTC’s district with Section Engineer and Maintenance Supervisors, researchers at the Kentucky Transportation Center (KTC) facilitated efforts to inventory routine maintenance activities, document how frequently each activity is done, and capture the ways in which maintenance functions are adjusted in response to special projects (which generally receive priority over general maintenance functions). Key products of this research include a Statewide Maintenance Calendar, which defines — based on a combination of stakeholder feedback and statistical analysis — optimal time intervals for undertaking key maintenance activities, as well as district-specific maintenance calendars. Having recourse to these calendars will help district staff more efficiently plan, schedule, and coordinate maintenance functions
Optimización metaheurística aplicada en la gestión de pavimentos asfálticos
Pavement engineering is a crossroads between geotechnical and transportation engineering with a sound base on construction materials. There are multiple applications of optimization algorithms in pavement engineering, emphasizing pavement management for its socioeconomic implications and back-calculation of layer properties for its complexity. A detailed literature review shows that optimization has been a permanent concern in pavement engineering. However, only in the last two decades, the increase in computational power allowed the implementation of metaheuristic optimization techniques with promising results in research and practice. Pavement management requires powerful optimization tools for multi-objective problems such as minimizing costs and maximizing the pavement state from network to project level with constrained budgets. A substantial amount of research focuses on genetic algorithms (GA), but new developments include particle intelligence (PSO, ACO, and ABC). The study must go beyond small-sized networks to improve the management of existing road infrastructure (pavement, bridges) based on mechanistic and reliability criteria.La ingeniería de pavimentos es una encrucijada entre la ingeniería geotécnica y la ingeniería de transporte con una sólida base en los materiales de construcción. Existen diferentes aplicaciones de los algoritmos de optimización en la ingeniería de pavimentos, las cuales enfatizan la gestión del pavimento por sus implicaciones socioeconómicas y el cálculo inverso de las propiedades de las capas por su complejidad. Una revisión detallada de la literatura muestra que la optimización ha sido una preocupación permanente en la ingeniería de pavimentos; sin embargo, solo en las últimas dos décadas, el incremento del poder computacional permitió la implementación de técnicas de optimización metaheurísticas con resultados prometedores en la investigación y en la práctica. La gestión del pavimento requiere poderosas herramientas de optimización para problemas con objetivos múltiples, como minimizar costos y maximizar el estado del pavimento desde el nivel de la red hasta el del proyecto con presupuestos limitados. Una cantidad sustancial de investigaciones se centra en los algoritmos genéticos (AG), pero los nuevos desarrollos incluyen inteligencia de partículas (PSO, ACO y ABC). El estudio debe ir más allá de las redes de pequeño tamaño para mejorar la gestión de la infraestructura vial existente (pavimento, puentes) con base en criterios mecanicistas y de confiabilidad
A Methodology to Determine Non-Fixed Performance Based Thresholds for Infrastructure Rehabilitation Scheduling
In an era of increasing demand and loading, aging infrastructure, and funding shortfalls, infrastructure agencies continue to seek cost-effective solutions to persistent and pervasive questions regarding the upkeep of their physical assets. One such question is the appropriateness of the current fixed condition thresholds used at several agencies for rehabilitation timing purposes, whether there is the possibility of having flexible rather than fixed thresholds, and determining what these thresholds should be. A related question is how these flexible thresholds may vary, depending on the objectives of the decision maker, the relative weight of agency and user costs, and the form of expression of the life-cycle cost associated with the candidate rehabilitation schedules. Fortunately, a number of past researchers have developed inputs that are valuable for addressing this issue. Also, there exists data from in-service infrastructure that could be used to test the hypotheses regarding the sensitivity of the optimal schedules
A Framework for Coordinating Water Distribution System and Pavement Infrastructure M&R Based on LCCA
The disruptions the public faces daily around the world due to urban infrastructure Maintenance and Rehabilitation (M&R) activities are having significant social, economic, and environment impacts on communities. With respect to water distribution systems, there have been millions of water main breaks in the U.S. since January 2000, with an average of nearly 700 water main breaks every day. The majority of these water utilities lie under paved roads, and the Open Cut method is the most widely used technology for repairing water main breakages. Subsequently, this continually increasing pipe breakage requires the destruction of pavements that may be in good condition and thereby results in not only untimely inconveniences to stakeholders, but can have large cost implications as well. Hence, in order to reduce the impact of pipe breakage on pavements in good condition and to minimize the user disruptions, it is essential to find a way to coordinate the M&R activities for both of these infrastructure systems. Therefore, this thesis presents a framework for coordinating pavement infrastructure and water distribution system M&R activities based on life cycle cost analysis. The proposed framework considers the costs and benefits associated with each treatment in a candidate scenario. The costs of each scenario consist of the agency costs (construction and subsequent maintenance) and the user costs incurred due to work zone activities. The benefits of each scenario are measured using monetized (savings in annual maintenance costs and vehicle operation costs due to pavement treatment and pipe valuation) and nonmonetized (treatment service life) approaches.
To demonstrate the framework, three scenarios (maintenance only, rehabilitation only, and a combination of both) are considered for pavement treatments, while only replacement is considered for water pipelines. The results were evaluated using the EZStrobe discrete event simulation system. Highway agencies and water utilities can use this methodology to evaluate different scenarios and enhance the robustness of their decision-making processes
Optimization of highway work zone decisions considering Short-term and Long-term Impacts
With the increase of the number, duration, and scope of maintenance projects on the national highway system, transportation agencies face great challenges in developing effective comprehensive work zone management plans which minimize the negative impacts on road users and workers. The types of maintenance operation, timing, duration, configuration, and user impact mitigation strategies are major considerations in developing work zone management plans. Some of those decisions may not only affect road users during the maintenance phase but also have significant impacts on pavement serviceability in future years.
This dissertation proposes a systematic methodology for jointly optimizing critical work zone decisions, based on analytical and simulation models developed to estimate short-term impacts during the maintenance periods and long-term impacts over the pavement life cycle.
The dissertation starts by modeling the effects of different work zone decisions on agency and user costs during the maintenance phase. An analytic one-time work zone cost model is then formulated based on simulation analysis results. Next, a short-term work zone decision optimization model is developed to find the best combination of lane closure and traffic control strategies which can minimize the one-time work zone cost. Considering the complex and combinatorial nature of this optimization problem, a heuristic optimization algorithm, named two-stage modified population-based simulated annealing (2PBSA), is designed to search for a near-optimal solution. For those maintenance projects that may need more detailed estimation of user delay or other impacts, a simulation-based optimization method is proposed in this study. Through a hybrid approach combining simulation and analytic methods along with parallel computing techniques, the proposed method can yield satisfactory solutions while reducing computational efforts to a more acceptable level. The last part of this study establishes a framework for jointly optimizing short-term and long-term work zone decisions with the objective of maximizing cost-effectiveness. Case studies are conducted to test the performance of the proposed methods and develop guidelines for development of work zone management plans
Use of road asset maintenance planning software in QDMR
Asset Management has over the last decade become the primary focus and objective of any worthwhile road authority. The focus of Road Asset Management is not merely of asset preservation but seeks to maintain the asset at a level, which optimises the returns to the community at large. These aims are achieved by continuously assessing the condition of the road network storing and synthesising the data and subsequently prioritising on the requirement hence providing the optimum treatment at the opportune time. In this background, Main Roads have progressively developed planning software - SCENARIO Millennium to assist their managers in developing maintenance strategies for their road networks. Considerable savings can be generated through timely maintenance and rehabilitation interventions and Main Roads envisage that their newly introduced SCENARIO software will be used as part of the program development process by their regions and districts. This dissertation explores the use of SCENARIO in the Southern District and process of identifying a program for rehabilitation works. This investigation of Scenario application follows a thorough review of the road asset management and the particular aspects of life cycle analysis. The report generally found that emphasis of asset management has in the last decade been fully recognised and embraced in the whole life management of assets. The use of SCENARIO software in the Southern District is yet to be implemented due to several reasons, such as the success in the current practices, staff shortfall and the fact that the software still requires a lot of local development to succeed etc. The report has found that Scenario could in addition to the identification of programmed maintenance requirements be tailored as an effective tool to timely predict the rehabilitation requirements. This involves further engineering analysis of the development of pavement weaknesses. Development of rules and different rehabilitation treatments would be an interesting regime that deserves further attention
A Framework for Comparative Life-Cycle Evaluation of Alternative Pavement Types
Researchers and practitioners agree that the selection of an appropriate pavement surface material type should be made based on a comprehensive evaluation that incorporates the costs and benefits associated with each alternative for the stakeholder. The most appropriate material type generally is the most cost-effective alternative over the pavement life cycle. Hypothetically, the most appropriate material type will vary across the various geographical regions of the U.S. because material costs and performance are influenced by the deterioration agents at play and the construction costs in a region. To address this issue, this dissertation proposes a comprehensive methodology to identify the most appropriate choice of pavement material type under different climatic and traffic conditions and thereby establish the conditions under which any one of two pavement materials can be considered superior. The case study of this dissertation uses data for an interstate highway section from the Long-Term Pavement Performance (LTPP) program database. The stakeholder costs include the agency cost, the user cost, and the community cost. The benefits (effectiveness) were evaluated using the concept of an area bounded by a performance curve and a pre-determined threshold. For each of the four LTPP zones and the two material types, the optimal maintenance and rehabilitation (M&R) schedule was established, and the corresponding optimal life cycle cost-effectiveness was determined using both deterministic and probabilistic sensitivity analysis. The results using the former approach suggest that the most cost-effective pavement material types in wet climates and dry climates are rigid and flexible, respectively, irrespective of the discount rate. When the latter approach was used, the flexible pavement material was found to be the stochastically-dominant pavement material type irrespective of the climatic zone or discount rate. This framework can be scaled down to a state or scaled up to the national or continental level, given the availability of cost, traffic loading, pavement condition, and environmental datasets
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