Pavement Maintenance Management [PDF]

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Department of Civil & Environmental Engineering, UWI 2016-2017, Semester 1, CVNG 3009 Highway Engineering Lecture Notes: Pavement Management



MODULE:



PAVEMENT MANAGEMENT



1. DEFINITIONS The American Association of State Highway and Transportation Officials (AASHTO) defines Pavement Management as the effective and efficient directing of the various activities involved in providing and sustaining pavements in a condition acceptable to the travelling public at the least life cycle cost (AASHTO, 1985). World Bank defined Pavement Management System (PMS) as any system that is used to store and process road and/or bridge inventory, condition, traffic and related data, for highway planning and programming (Mc Pherson and Bennett 2005). A simpler definition of pavement management system is a tool that can be used to make informed decision about the maintenance and rehabilitation of a pavement network. Pavement Management is defined as being a process and a pavement management system being the application or implementation of the process in a working, operational environment such as in a public agency.



2. INTRODUCTION The concept of providing pavements and maintaining them in acceptable condition is as old as the first pavement. As pavement networks grew slowly in the first half of the 20th century and then quickly in the 1950s and 1960s, simple procedures or experience that had worked previously was no longer able to manage these burgeoning networks. Instead a more holistic systems approach was needed. Pavement management systems are developed to provide the road authorities information on: • • • • •



The actual pavement condition The future pavement condition Current maintenance needs and budget requirements Future maintenance need and budget requirements Consequences of postponing maintenance both in terms of maintenance needs and budget requirements.



Through the use of pavement management systems one should arrive to an optimum use of the available resources (money, manpower, materials) given the constraints that are set by the road authorities (available budget, minimum audition requirements, etc.).



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Department of Civil & Environmental Engineering, UWI 2016-2017, Semester 1, CVNG 3009 Highway Engineering Lecture Notes: Pavement Management



Pavement management systems are needed because public demands for high levels of pavement quality are expected to increase in the near future, especially when the main and secondary road systems begins to require extensive repairs. Also funding for highway maintenances operations can be expected to become more stringently controlled in the near future. In those situations pavements may deteriorate to such an extent that road users costs may increase rapidly (vehicular deterioration) because of the poor pavement condition. If these situations are likely to happen, an overall approach towards pavement management is recommended which includes the effects of pavement condition and pavement maintenance on road user costs.



3. LEVELS OF PAVEMENT MANAGEMENT



Pavement management can occur at the network level and the project level.



Network level management involves the evaluation of all pavements under an agency’s jurisdiction. The primary objective of network level management is to develop an agency-wide prioritized pavement repair program that will yield the least total cost or greatest benefit under overall budget constraints. Network level management works on more approximate data than does project level management. Project level management focuses on a particular location and usually comes after network level analysis in local agencies. Once a segment has been identified as a candidate for repair at the network level, an engineering analysis is then performed at the project level. This level of analysis 2



Department of Civil & Environmental Engineering, UWI 2016-2017, Semester 1, CVNG 3009 Highway Engineering Lecture Notes: Pavement Management



requires a more detailed evaluation, since the information gathered at the network level does not normally include the type of data needed to make detailed design decisions for an individual project. Additional testing, such as coring and nondestructive testing, is often conducted during a project level analysis to provide additional knowledge about pavement condition and cause of deterioration.



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Department of Civil & Environmental Engineering, UWI 2016-2017, Semester 1, CVNG 3009 Highway Engineering Lecture Notes: Pavement Management



Basic Blocks of Activities



DATA



CRITERIA



ANALYSES



SELECTION



Network Level (Administrative and Technical Decisions)



Project Level (Technical Decisions)



• Sectioning and data acquisition (field data on roughness, surface distress, deflection, etc., plus traffic, cost and environmental data) • Portrayal of present status • Data processing and evaluation



• Sub sectioning and detailed data acquisition (materials, traffic, unit cost) • Data processing and evaluation



• Minimum or maximum acceptable levels (serviceability, surface distress, structural adequacy, etc.) • Maximum program costs • Maximum levels of traffic interruption • Selection basis (i.e. cost-effectiveness)



• Minimum or maximum as built conditions (roughness, surface friction, structural adequacy, etc.) • Maximum project costs • Selection basis (i.e. minimum net present worth of costs)



• Present needs sections, deterioration predictions and future needs sections • Maintenance and rehabilitation alternatives for needs sections deterioration predictions, life cycle costs and benefits • Priority analysis for different budget levels or for specified performance standard(s)



• Within project rehabilitation or maintenance alternatives, detailed field and laboratory tests • Deterioration predictions (serviceability and distress) for alternatives • Economic evaluation of alternatives.



• Determination of final programs of maintenance and rehabilitation. • Program recommendations, administrative and elected body approvals.



• Best within project or section maintenance and/or rehabilitation alternatives.



• Establishment of work schedules, sequences, contract tenders and awards. IMPLEMENTATION • Program monitoring • Budget and financial planning updates • Inventory and data base updates



• Construction activities, work control and quality assurance, as built records • Maintenance activities and management records • Data base updates



Table 1.1 An activity/decision based generic structure for pavement management (Haas 87)



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Department of Civil & Environmental Engineering, UWI 2016-2017, Semester 1, CVNG 3009 Highway Engineering Lecture Notes: Pavement Management



Approaches to pavement management tend to attack this two-level system either from the top down by dealing with network-level decisions first, or from the bottom up by dealing with projectlevel decisions first. Either method can be quite detailed or relatively simple depending upon data amount and quality and desired analytical capabilities. For example, at the project level detailed considerations is given to an alternative design, construction, maintenance and rehabilitation activities for specific projects. This might be accomplished by comparing benefit-cost ratios of several design alternatives and picking the design alternative that provides the desired benefits for the least total cost over the projected life of the project.



Comparison of Approaches Network Level Approach Advantages The network-level approach is characterized by top-down logic system optimization, data, large data and resource requirements, and sophisticated models. Its chief advantages are that it can: 1. 2. 3. 4. 5.



Optimize solutions for the entire network. Quickly and accurately produce conditional scenarios. Prioritize broad areas of maintenance, reconstruction and rehabilitation. Use consistent inputs in scenario comparisons More easily obtain top management attention



Project Level Approach Advantages The project-level approach is characterized by simpler models, less data aggregation, fewer data and resource requirements, less reliance on feedback for success and better understanding. Its chief advantages are: 1. 2. 3. 4. 5.



Relies less on aggregate data Able to be used with little data Better link between network-level and project level management decisions Less dependent upon feedback for success Easier to obtain buy in from others



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Department of Civil & Environmental Engineering, UWI 2016-2017, Semester 1, CVNG 3009 Highway Engineering Lecture Notes: Pavement Management



4. BASIC FRAMEWORK FOR PAVEMENT MANAGEMENT In order for a pavement management system to function to the full extent of its definition, it requires a coordinated set of activities. These relate to the data or information, planning or programming, design, construction, maintenances, periodic evaluation, and research (Haas 1997).



Figure showing Framework for and major classes of activities in a pavement management system (RTAC 77)



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Department of Civil & Environmental Engineering, UWI 2016-2017, Semester 1, CVNG 3009 Highway Engineering Lecture Notes: Pavement Management



Planning Planning involves the analysis of the road system as a whole, typically requiring the preparation of medium to long term, or strategic, estimates of expenditure for road development and preservation under various budget and economic scenarios. Predictions may be made of road network conditions under a variety of funding levels in terms of key indicators together with forecasts of required expenditure under defined budget heads. The physical highway system is usually characterized at the planning stage by: Characteristics of the road network: • Grouped in various categories and defined by parameters such as:
Load class or hierarchy
Traffic flow/loading/congestion
Pavement types
Pavement condition • •



Length of road in each category Characteristics of the vehicle fleet which use the road network



The results of the planning exercise are of most interest to senior policy makers in the roads sector, both political and professional. A planning unit will often undertake this work.



Programming Programming involves the preparation, under budget constraints, of multi-year road work and expenditure programs in which sections of the network likely to require maintenance, improvement or new construction, are selected and analyzed. It is a tactical planning exercise. Ideally, cost-benefit analysis should be undertaken to determine the economic feasibility of each set of works. The physical road network is considered at the programming stage on a link-by-link basis, with each link characterized by homogeneous pavement sections defined in terms of physical attributes. The programming activity produces estimates of expenditure in each year, under defined budget heads, for different types of roadwork and for each road section. Budgets are typically constrained, and a key aspect of programming is to prioritize the road works in order to find the best use of the constrained budget. Typical applications are the preparation of a budget for an annual or a rolling multi-year work program for a road network, or sub-network. Managerial-level professionals within a road organization normally undertake programming activities, perhaps within a planning or a maintenance department. Preparation This is the short-term planning stage where road schemes are packaged for implementation. At this stage, designs are refined and prepared in more detail; bills of quantities and detailed costing are made, together with work instructions and contracts. Detailed specifications and costing are likely to be drawn up, and detailed cost-benefit analysis may be carried out to confirm the feasibility of the final scheme. Works on adjacent road sections may be combined into packages of a size that is cost-effective for execution. Typical preparation activities are the detailed design of: 7



Department of Civil & Environmental Engineering, UWI 2016-2017, Semester 1, CVNG 3009 Highway Engineering Lecture Notes: Pavement Management




An overlay scheme
Road improvement works (for example, construction along a new alignment, road widening, pavement reconstruction, etc.) For these activities, budgets will normally already have been approved. Preparation activities are normally undertaken by middle to junior professional staff and technicians within a design or implementation department of a road organization, and by contracts and procurement staff. Operations These activities cover the on-going operation of an organization. Decisions about the management of operations are made typically on a daily or weekly basis, including the scheduling of work to be carried out, monitoring in terms of labor, equipment and materials, the recording of work completed, and use of this information for monitoring and control. Activities are normally focused on individual sections or sub-sections of a road, with measurements often being made at a relatively detailed level. Operations are normally managed by subprofessional staff, including works supervisors, technicians, clerks of works, and others. This phase also includes the maintenance phase or the actual operations of applying maintenance treatments and the acquisition and processing of the data. Evaluation The evaluation of pavements includes the establishment of sections and the periodic measurements of such items as pavement deflection or structural adequacy, roughness or ride quality, surface distress, surface friction, traffic, etc. it also usually includes the analysis of the data for use in the other phases of the pavement management system. Data Base and Research The data base section is identified as an information base for all pavement management activities. The importance of research as a major phase of the pavement management systems depends largely upon the available resources and the particular requirements of the agency.



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Department of Civil & Environmental Engineering, UWI 2016-2017, Semester 1, CVNG 3009 Highway Engineering Lecture Notes: Pavement Management



5. PAVEMENTT MANAGEMENT SYSTEM



One of the products included a definition for pavement management system: "a system which involves the identification of optimum strategies at various management levels and maintains pavements at an adequate level of serviceability. These include, but are not limited to, systematic procedures for scheduling maintenance and rehabilitation activities based on optimization of benefits and minimization of costs." A 13-step plan is normally required for the development and implementation of a pavement management system: 1.



Decision to start.



2.



Commitment from top management.



3.



Develop preliminary work plan.



4.



Establish steering committee of top management and division heads.



5.



Develop detailed work plan.



6.



Evaluate software and hardware requirements.



7.



Develop preliminary system with procedures for data collection, processing, analysis, and optimization.



8.



Verification.



9.



Demonstration to potential users and decision-makers.



10.



Location of the pavement management system unit within the state highway agency.



11.



Full-scale implementation and evaluation.



12.



Routine operation of the pavement management system.



13.



Maintain and improve.



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Department of Civil & Environmental Engineering, UWI 2016-2017, Semester 1, CVNG 3009 Highway Engineering Lecture Notes: Pavement Management



The best or optimal recommendation at the project level may not be the optimal solution for the network. The easiest illustration of this relationship can be posed by the question: Do I spend a major share of funds available on one or two projects to achieve acceptable performance over an extended period of time, or do I distribute the funds over several projects with reduced expectations of the service life but an overall raising of the serviceability of the network? The answer can only be addressed at the network level, and depending on a variety of factors or considerations, such as user costs, the final decision could go either way. The major problems that contribute to skepticism about the viability of PMS are: •



Natural resistance to change in the way decisions are made.



•



Doubts about the reliability of prediction models.



•



Cost and time factors needed to develop a pavement management system.



•



Indications that no reduction in agency budget would occur even though a greater percentage of needs could be accommodated through more effective use of the funds available.



•



Resources needed to maintain and update.



•



The effect of institutional issues — turf issues — on traditional decision-making prerogatives.



•



The need for a well-trained staff, uniquely trained for PMS.



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Department of Civil & Environmental Engineering, UWI 2016-2017, Semester 1, CVNG 3009 Highway Engineering Lecture Notes: Pavement Management



6. PAVEMENTT MANAGEMENT SYSTEM DATA Data and/or information are the foundation of any management system. This is particularly true for pavement design and management where decisions made without adequate, reliable and consistent data can lead to costly errors. Inventory Data An inventory of the existing pavements in an agency network is a key component of their pavement management system. It can range from very extensive and detailed to an inventory which is limited to only certain essential items of geometry, location pavement type, etc. The various types of inventory data generally fall into the following classes: 1. Section references and description 2. Geometry 3. Pavement structure 4. Traffic history 5. Cost data Historical Data Pavement management is not a single time or periodic time application process. It has a long term spectrum of connection or follow-through from the initial planning and programming to design to construction to ongoing maintenance and in-service monitoring. Thus it is important to acquire data over time on construction, maintenance and performance in order to update models, procedures and programs. This is only possible, however, with good historical data. Condition Data Pavement condition data are used as the basis for every decision made with the PMS. If the condition data are not reliable, none of the recommendations of the system will be reliable. In Washington State, three types of condition assessment are performed by local agencies:
visual rating,
nondestructive testing (NDT), and
destructive testing. The type of condition data needed to effectively manage a pavement network will depend upon the agency and the level of data analysis required.



Types of Data and Typical Uses A generic classification of the types of pavement management data has been developed and categorized in six classes, as well as some of the typical uses at both the network and project level. Another aspect is that the data was further identified and classified primarily relating to rehabilitation (R), maintenance (M) or both (R+M), as indicated in brackets in the table below. For 11



Department of Civil & Environmental Engineering, UWI 2016-2017, Semester 1, CVNG 3009 Highway Engineering Lecture Notes: Pavement Management



most pavements 1 or 2 classes are need however for new pavements all the classes identified are used. Data Class and Component Network Level Data Items 1. PERFORMANCE RELATED Roughness (R)



Surface Distress (R+M)



Surface Friction (R+M)



Deflection (R)



a) Describe present status b) Predict future status (deterioration curves of roughness vs time or loads) c) Basis for priority analysis and programming. a) Describe present status b) Predict future status (deterioration curves) c) Identify current and future needs d) Maintenance priority programming e) Determine effectiveness of alternative treatments



a) b) c) d)



a) Describe present status b) Predict future status (deterioration curves) c) Identify structural inadequacies d) Priority programming of rehabilitation e) Determine seasonal load restrictions a)



Layer Material Properties (R)



2. HISTORIC RELATED Maintenance History (R+M)



Describe present status Predict future status Priority programming Determine effectiveness of alternative treatment



Estimate section to section variability b) Develop basis for improved design standards a) Maintenance programming b) Evaluate maintenance effectiveness c) Determine cost-effectiveness of alternative designs and treatments



Project Level



a)



Quality assurance (as-built quality of new surface) b) Create deterioration curves c) Estimate overlay quantities



a)



Selection of maintenance treatment b) Identify needed spot improvements c) Develop maintenance quantity estimates d) Determine effectiveness of alternative treatments. a)



Identify spot or section rehabilitation requirements b) Determine effectiveness of alternative treatments



a) Input to overlay design b) Determine as-built structural adequacy c) Estimate remaining service life d) Estimate remaining load restrictions



a) Input to overlay design b) Provide as-built records



a)



Identify problem sections



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Department of Civil & Environmental Engineering, UWI 2016-2017, Semester 1, CVNG 3009 Highway Engineering Lecture Notes: Pavement Management



Construction History (R+M)



a) Evaluate construction effectiveness b) Determine cost-effectiveness of alternative designs and construction practices c) Determine need for improved quality assurance procedures



a) Provide as-built records b) Provide feedback to design



a) Priority programming b) Input to estimate general performance/distress trends



a) Input for pavement design b) Identify traffic handling methods c) Estimate remaining service life



a) Develop counter measures b) Priority programming



a) Identify high-risk sites b) Develop counter measures



a) Priority programming b) Selection of management strategies



a)



a) Selection of management strategies b) Priority programming



a) Economic evaluation b) Life cycle cost comparisons



a)



Develop general policy or standards



a)



Curvature (R)



a)



Develop general policy or standards



a) Determine section constraints b) Assess safety



Cross Slope (R)



a)



Develop general policy or standards



a) Assess drainage b) Assess safety



Grade (R)



a)



Develop general policy or standards



a) Assess drainage b) Assess safety



Shoulders / Curbs (R+M)



a)



Develop general policy or standards



a) Assess safety b) Assess drainage



a)



Evaluate general network performance



a)



Evaluate section performance



a)



Evaluate general network performance



a)



Evaluate section performance



Traffic History (R+M)



Accident History (R+M)



3. POLICY RELATED Budget (R+M) Available Alternatives (R+M)



4. GEOMETRY RELATED Section Dimensions (R)



5. ENVIRONMENT RELATED Drainage (R+M)



Climate (R)



Determine cost limitations



Determine section constraints



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Department of Civil & Environmental Engineering, UWI 2016-2017, Semester 1, CVNG 3009 Highway Engineering Lecture Notes: Pavement Management



6. COST RELATED New construction costs (R)



a) Priority programming b) Selection of network investment strategies



Maintenance Costs (R+M)



a) Priority programming b) Selection of network maintenance strategies



Rehabilitation Costs (R)



a) Priority programming b) Selection of network rehabilitation strategies



User Costs (R)



a) Priority programming b) Selection of management strategies



a) Economic evaluation b) Selection of strategy



a)



Evaluation of maintenance effectiveness b) Selection of maintenance sections a) Economic evaluation b) Selection of rehabilitation strategies a) Economic evaluation b) Selection of mitigation strategies



Table 2: Generic data classes and typical uses



7. DATA ANALYSIS The database alone is of little use to pavement managers without a method to identify and prioritize needs, predict future condition, assess costs and benefits, and select effective management strategies based on existing data. A critical component of a PMS is the data analysis portion of the system. It is here that potential rehabilitation needs are evaluated and prioritized for planning and scheduling budget needs so that the agency makes the best use of the limited funds available to it for rehabilitation work. Most pavement management software provides the following analytical capabilities: determination of current condition levels, prediction of future pavement condition, identification of feasible repair alternatives, selection of the optimal repair alternative, prioritization of projects, and development of multi-year repair programs and maintenance plans. In addition, pavement management software may contain analytical routines to assist the user in pavement design, construction, and maintenance. As with the data collection component, the level of sophistication required for data analysis should be tailored to meet the needs of the agency implementing the PMS.



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Department of Civil & Environmental Engineering, UWI 2016-2017, Semester 1, CVNG 3009 Highway Engineering Lecture Notes: Pavement Management



8. SUCCESS FACTORS FOR ROAD MANAGEMENT SYSTEMS A recent World Bank study (McPherson and Bennett, 2005) focused on success factors for road management systems. The study revealed that the successful implementation of a computerized road management system relies on three fundamental components, namely processes, people and technology. Linked to these components is sufficient funding (see the figure below).



Processes: - The road management system must have an active role in the road agency. The pavement management system must be viewed as an integral component in the highway agency’s monitoring and planning process. The outputs from the RMS should be used to prepare Annual Reports as this helps ensure that the data are collected regularly and the system is applied. People: - The road management system must be fully institutionalized and supported There must be sufficient budget allocated to operate the RMS and collect the necessary data. There must be an organizational unit established to manage, monitor and continually improve pavement management system implementation. This organizational unit must be appropriately staffed, have clear job responsibilities, and must have clear reporting responsibilities to upper management and executive level. Information Technology: - The it components must be appropriate Information Technology (IT) is becoming increasingly complex, as the demands for sharing information between applications and users grows. Any medium to large organization should have a strong IT division and an IT strategy to ensure that the benefits of IT are realized. The pavement management system implementation should fit within the overall IT strategy of the agency, and should be properly supported from an IT perspective. 15



Department of Civil & Environmental Engineering, UWI 2016-2017, Semester 1, CVNG 3009 Highway Engineering Lecture Notes: Pavement Management



Data Collection: - Data collection must be appropriate and sustainable Only the key data that are required in decision-making should be collected and stored in the pavement management system. These data should be collected at the minimum level of detail with the most appropriate data collection technology given the constraints and capabilities of the agency. Where possible, data collection should be outsourced. There must be explicit data collection policies and procedures for the agency, in a manner understood by all involved with data collection. There must also be strict data quality assurance procedures in place so that all system users have confidence in the data and analyses provided to them.



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