Dissertations / Theses on the topic 'Pavement management systems (PMSs)'

The growing interest in pavement management systems (PMSs), both in South Mrica and internationally, has been in response to a shift in importance from the construction of new roads to the maintenance of the existing paved network coupled with increasingly restrictive road funding. In order to develop a balanced expenditure programme for the national roads of South Africa there is a need to predict the rate of deterioration of a pavement and the nature of the changes in its condition so that the timing, type and cost of maintenance needs could be estimated. Internationally these expected changes in pavement condition are predicted by pavement deterioration models, which normally are algorithms developed mathematically or from a study of pavement deterioration. Since no usable pavement deterioration models existed locally, it was necessary to evaluate overseas literature on pavement deterioration prediction models with the aim of identifying models possibly applicable to the national roads of South Africa. Only deterioration models developed from the deterioration results of inservice pavements under a normal traffic spectrum were evaluated. Models developed from accelerated testing were avoided since these models virtually eliminated long·term effects (these are primarily environmental but also include effects of the rest periods between loads), and that the unrepresentative traffic loading regimes can distort the behaviour of the pavement materials, which is often stress dependent. Models developed from the following studies were evaluated: • AASHO Road Test • The Kenya study • Brazil-UNDP study (HDM-ill models) • Texas study Of all the above models studied that were developed from major studies it was concluded that the incremental models developed during the Brazil study, were the most appropriate for further evaluation under South African conditions. A sensitivity analysis was conducted on the HDM-III models to evaluate their sensitivity to changes in the different parameters comprising each model. The results obtained from the sensitivity analysis indicate that the incremental roughness prediction model incorporated into the HDM-III model tends to be insensitive to changes in most parameters. Accuracy ranges for input data were, however, also identified for parameters which indicated an increase in sensitivity in certain ranges. The local applicability of the HDM-III deterioration models were finally evaluated by comparing HDM-III model predictions with the actually observed deterioration values of a selected number of national road pavement sections. To enable the above comparison, a validation procedure had to be developed according to which the format of existing data could be transformed to that required by the HDM-ill model, as well as additional information be calculated. From the comparison it was concluded that the HDM-III models are capable of accurately predicting the observed deterioration on South African national roads, but that for most models calibration is needed for local conditions. Guidelines regarding recommended calibration factor ranges for the different HDM-ill models are given. Finally it is recommended that the HDM-III models should be considered for incorporation into a balanced expenditure programme for the national roads of South Africa.
Dissertation (MEng)--University of Pretoria, 1993.
gm2014
Civil Engineering
MEng
Unrestricted

Analisi delle principali caratteristiche delle pavimentazioni flessibili, dei materiali costituenti la miscela di conglomerato bituminoso e delle tipologie di ammaloramento ricorrenti. Studio del metodo di progetto dell'AASHTO Interim Guide, per la progettazione delle strade di nuova realizzazione. Applicazione del metodo semi-empirico dell’AASHTO Interim Guide a dieci casi di studio di strade esistenti del tessuto urbano del Comune di Ravenna. Analisi dell’indicatore di stato PSI misurato mediate attività di rilievo visivo e strumentale ARAN, dei dati di traffico ottenuti da rilievo strumentale e sondaggio delle strutture delle strade esaminate mediante carotaggio dei pacchetti stradali. Determinazione degli assi standard da 8,2 t residui e degli anni di vita utile residui delle pavimentazioni. Accenni alle principali tipologie di manutenzione e alle soglie di intervento. Creazione di curve di decadimento (PSI - assi standard e PSI - anni di vita utile) allo scopo di fornire un modello di previsione del degrado finalizzato a fornire un metodo per la manutenzione preventiva in ambito urbano.

The purpose of this research is to develop a model and solution methodology for selecting and scheduling timely and cost-effective maintenance, rehabilitation, and reconstruction activities (M & R) for each pavement section in a highway network and allocating the funding levels through a finite multi-period horizon within the constraints imposed by budget availability in each period, frequency availability of activities, and specified minimum pavement quality requirements. M & R is defined as a chronological sequence of reconstruction, rehabilitation, and major/minor maintenance, including a "do nothing" activity. A procedure is developed for selecting an M & R activity for each pavement section in each period of a specified extended planning horizon. Each activity in the sequence consumes a known amount of capital and generates a known amount of effectiveness measured in pavement quality. The effectiveness of an activity is the expected value of the overall gains in pavement quality rating due to the activity performed on a highway network over an analysis period. It is assumed that the unused portion of the budget for one period can be carried over to subsequent periods. Dynamic Programming (DP) and Branch-and-Bound (B-and-B) approaches are combined to produce a hybrid algorithm for solving the problem under consideratioin. The algorithm is essentially a DP approach in the sense that the problem is divided into smaller subproblems corresponding to each single period problem. However, the idea of fathoming partial solutions that could not lead to an optimal solution is incorporated within the algorithm to reduce storage and computational requirements in the DP frame using the B-and-B approach. The imbedded-state approach is used to reduce a multi-dimensional DP to a one-dimensional DP. For bounding at each stage, the problem is relaxed in a Lagrangean fashion so that it separates into longest-path network model subproblems. The values of the Lagrangean multipliers are found by a subgradient optimization method, while the Ford-Bellman network algorithm is employed at each iteration of the subgradient optimization procedure to solve the longest-path network problem as well as to obtain an improved lower and upper bound. If the gap between lower and upper bound is sufficiently small, then we may choose to accept the best known solutions as being sufficiently close to optimal and terminate the algorithm rather than continue to the final stage.

This study aimed at investigating the current practices and methods adopted by roads agencies around the world with regard to collection, analysis and utilization of the data elements pertaining to the main pavement condition indicators in pavement management systems (PMS). It also aimed at identifying the main predictors associated with each condition indicator and the factors that govern pavement structural and functional performance. Development of a new performance index that incorporates parameters or measures related to the main condition indicators (surface defects, roughness, deflection and skid resistance) and establishing the weight to be assigned to each indicator based on the relative impact on pavement condition was also one of the main objectives of this study. Thousands of pavement sections were subjected to thorough testing and inspection over the last few years to collect data pertaining to the main condition indicators. The collected data encompass visual distress survey, deflection measurements, roughness and skid resistance measurements. Collection of various condition indicators was accomplished according to well known international standards. The collected data were processed, tabulated and analyzed for the purpose of development of performance models and to prove certain theories or good practices.
Advanced tools and machines were utilized to collect these data with a high degree of accuracy. The Falling Weight Deflectometer (FWD) was used to collect deflection data for structural analysis. Two Non-contact laser roughness measuring devices mounted on vehicles were heavily used for collecting roughness, texture, and rutting data. Distress data were collected using a manual procedure adopted and standardized at the Pavement Management System Unit of Dubai Emirate. Powerful engineering and statistical softwares were used in the analysis for the purpose of processing the data, back calculating the main parameters pertaining to pavement response, establishing the correlation matrices between various dependent variables and their predictors, and finally, applying linear and non linear regression analysis to develop reliable and predictable deterioration models for the uses of pavement management system. The analysis procedure was supplemented by a vast literature review for the up to date information along within deep investigations and verifications for some of the current practices, theories and models used in pavement design and pavement evaluation with more emphasis on the inherent drawbacks associated to these models and procedures. The study confirmed that pavement condition deterioration and performance can be best predicted and evaluated based on four main condition indicators; First, surface distress to assess the physical condition of the pavements and detect the inherent problems and defects caused by various factors affecting pavement performance. Second; roughness measurements to evaluate the riding quality of the pavement.
Third; deflection to calculate pavement response (stress and strains) and to assess pavement structural capacity and calculating the remaining life, and finally, skid resistance measurement to assess the level of safety and surface texture properties. Thorough study and investigation of the physical condition indicators and the associated parameters, confirmed that pavement distress data are vital elements in each pavement management system. Distress data can be used effectively to identify the main problems associated with pavement performance, causes of deterioration, maintenance measures needed to prevent the acceleration of the distress, the rehabilitation schemes needed to improve the pavement condition and finally to prepare maintenance work programs and to estimate the annual maintenance needs under an open or limited budget. Alligator cracking was found to have the heaviest impact on pavement condition. Distress density, probable causes of deterioration and distress propagation rate are the required parameters in PMS. Roughness was found to have a basic influence on pavement condition and the type of selected treatment. The use of Roughness data in terms of International Roughness Index (IRI) can be optimized in PMS by using this indicator in the following forms:
Roughness, as an objective measure, can be used as a good performance predictor of the current riding quality of pavements in service and reflects the inherent imperfections and built-in irregularities embodied in the road pavement surface. Roughness measurement can be used as a reference to establish construction specifications and provides through the PMS system an organized feedback approach to correct the persistent design deficiencies detected after road construction. Roughness can be used effectively in the planning process for maintenance works and to select the candidate sections through calculating the functional remaining life based on the estimated terminal value using Roughness-Age, Roughness-ESAL, and Roughness-PSI models. Lane–IRI along with the Difference between the left and right wheel IRI values, termed as “ Yaw” are the most suitable forms to be used in PMS to report about roughness characteristics. Yaw term can be used effectively to report or feed back about geometric imperfections that exist on the road surface such as improper cross slope, shoving and the probable drainage problems. The roughness cumulative distribution curves can be used as a planning tool in PMS to report at the network level. These curves indicate the network health and the required funding at different level of risks, so proactive measures can be taken and the required budgets can be made available.
Deflection data were found to form a basic component of the PMS. It was found that these data can be used at both network and project levels. Direct deflection measurements were found Not to be the ideal form to report about structural capacity at the network level. It is rather can be used at project level to detect weak spots and critical pavements layers. At the network level, the back calculated parameters from deflection basin such as Pavement Modulus (Ep), Asphalt and Pavement Curvature (CUR), Cross Sectional Area and the other deflection basin characteristics are much more appropriate for reporting about pavement structural conditions and calculating the structural remaining life in PMS. The design deflection and curvature that characterize the pavement have been found to be calculated based on the mean along with the two times the standard deviation of the measured data. The Effective Structural Number (SNeff) was found to have good correlations with the Total Pavement Thickness (Ht), the value of the deflection measured at the center of the loading plate ( D0 ) and the difference between D0 and the deflection measured at 450mm from the center of the loading plate ( D0 - D450 ). The first two variables were found to account for more than 92% of the structural capacity prediction model.
Traffic variable in terms of the accumulated standard repetitions (ESAL) was found to account for more than 60% of the deflection model predictability. Other variables such as E value, asphalt and base layer thicknesses can improve the predictability of the model if included. The concept of the relative value of effective pavement modulus to the original pavement modulus (Eeff/E0) was found to gives a reliable representation about the exhausted and the remaining life of the in-service pavement structure. The study showed that the pavement is reported to be structurally failed, when the effective asphalt or pavement modulus is about 20 - 35 % of its original design value which is equal to the modulus of the unbound material. It was also found that when the area of the fatigue cracking and the patching distresses exceeds 17% of the total pavement section area, or the depth of rutting is more than 15mm, the pavement is reported to be structurally failed and major rehabilitation or reconstruction should be applied. Skid resistance can be reported in the form of International Friction Index (IFI), as a well defined universal index, along with other two numbers; F60 Friction (Microtexture) related number measured at 60 km/h velocity and Macrotexture related number and Vp, which constitute the IFI index can be used in Pavement management system applications to report about skid resistance characteristics and the network level of safety. These three figures can be used to report about pavement condition, accidents, airports operations, and maintenance management surveys.
In this study, new methods and models were developed and suggested to be used in PMS as an alternative to the current available methods which were found to be impractical in certain cases. Finally, further research efforts are recommended to explore the uses of other parameters in particular those related to deflection basin analysis, cross sectional area, curvature, and pavement moduli. Skid resistance testing and reporting method should be subjected to further research works for the purpose of standardizing reporting methods, identifying the relative impact of main predictors i.e. megatexture, macrotexture and microtexture components and to develop performance models.

Municipal housing companies (MHCs) can be seen as hybrid organizations, operating under multiple institutional logics that are likely in tension with each other. Measuring the performance of hybrid organizations is a much harder exercise than measuring the performance of pure public or pure private entities. There is a lack of research in this area. To fill this gab van Helden and Reichard’s (2016a) proposed a framework that assigns typical characteristics to PMS in hybrids. The authors call for empirics to test the framework. Accordingly, the first purpose of the thesis is to test the hypotheses of this framework in practice, using a case study approach of two MHCs, MKB AB and LKF AB. The second purpose is to shed light on challenges, conflicts and even propose solutions for MCS/PMS. The thesis ended up by proposing a conceptual model for MCS/PMS that aims to reconcile conflicting goals and logics. The model integrates strategic management control tools (BSC and ERP) to support strategy implementation and formulation as well as to reconcile the different interests of the various stakeholders.

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2001.
Includes bibliographical references (leaf 75).
In the Information Technology Era today, software has been one of the most significant elements to help organizations achieve increased productivity and commercial success. For developers to create effective software, an appropriate development process must be applied. Generally, the process of developing software can be considered as having six phases: requirements engineering, design, implementation, testing, maintenance, and project management. Over the past thirty years, different kinds of life cycle models have been developed by applying these phases to provide developers with the most appropriate procedures for projects of various types. In addition, a set of development fundamentals should be considered during the process to optimize time, effort and cost in developing each project. This thesis studies the software development process and its effects on the development schedule of a Pavement Management and Inspection System (PMIS) project as a case study. From the case study, it can be concluded that choosing the appropriate life cycle model and applying the pertinent fundamentals, with the essential components of the development speed, can lead the project to be a success. Problems encountered during the development process are also valuable information to study as it may prevent them from occurring in the future.
by Warit Durongdej.
M.Eng.

The research presented in this thesis investigates the effect the data collection process has on the results of the economic analysis in pavement management systems. The incorporation of pavement management systems into software packages has enabled local governments to easily implement and maintain an asset management plan. However a general standard has yet to be set, enabling local governments to select from several methods of data collection. In this research, two pavement management system software packages with different data collection methods are analyzed on the common estimated recommended M&R cost provided by their respective economic analysis. The Transportation Asset Management Software (TAMS) software package developed by the Utah LTAP Center at Utah State University consists of a data collection process composed of nine asphalt pavement distress observations. The Micro PAVERTM software package developed by the Army Corps of Engineers consists of a data collection process composed of 20 asphalt pavement distress observations. A Latin-hypercube sample set was input into each software package, as well as actual local government pavement condition data for the City of Smithfield, Utah and the City of Tremonton, Utah. This resulted in six total data sets for analysis, three entered and analyzed in TAMS and three entered and analyzed in Micro PAVERTM. These sample sets were then statistically modeled to determine the effect each distress variable had on the response produced by the economic analysis of estimated recommended M&R costs. Due to the different methodologies of pavement condition data collection, two different statistical approaches were utilized during the sensitivity analysis. The TAMS data sets consisted of a general linear regression model, while the Micro PAVERTM data sets consisted of an analysis of covariance model. It was determined that each data set had varying results in terms of sensitive pavement distresses; however the common sensitive distress in all of the data sets was that of alligator cracking/fatigue. This research also investigates the possibility of utilizing statistically produced models as a direct cost estimator given pavement condition data.

Preventive maintenance has the potential to improve network condition by retarding future pavement deterioration. The Virginia Department of Transportation uses its pavement management system to determine maintenance targets for each district. The districts then use these recommendations to select pavements that will receive maintenance and the types of treatments that will be applied. Each district has a different approach to preventive maintenance. There was a need for more consistent preventive maintenance practices across the state.
This thesis outlines guidelines for the implementation of a preventive maintenance policy. Preventive maintenance treatments currently being used within Virginia include chip seal, slurry seal, microsurfacing, and thin hot mix asphalt overlays. Historical pavement condition data was obtained from the VDOT PMS for these treatments and treatment performance models were developed. A district level treatment selection tool was developed to assist the district level decision making process. A prioritized list of pavement sections was generated, maximizing the cost-effectiveness of the selected treatments subject to budgetary constraints set by the central office.
The treatment selection tool was then run for each pavement classification in each district. The results of this analysis were presented. Although the recommended budget for each district was very close to the targets set by the central office, the recommended lane miles for each district were about half the targets set by the central office.  It is believed that the unit costs used in this analysis were higher than those used in the VDOT PMS analysis. This selection tool has the potential to be a very powerful decision support tool if the unit costs are representative of what the expected treatment costs are for each district.

Master of Science

A pavement investment and management process has a dynamic structure with cause and effect. Better investment decisions for maintenance will increase the condition of the flexible pavement and will end up with a better level of service. Therefore, better investments decisions on pavement maintenance will increase the economic growth and global competition for the area. However, improper allocation of money and resources would end up with further deteriorations of the facilities. So asset management encourages highway maintenance managers to spend their scarce budget for the maintenance that is really needed. A well-developed pavement management simulation model will allow highway maintenance managers to consider the impact of choosing one maintenance policy alternative versus another through what-if analysis and having informed decisions. Discrete event simulation (DES) is an alternative method of analysis that offers numerous benefits in pavement management. Unlike the models currently in use, a decision support model created by utilizing the DES technique would allow fractionalizing the pavement in smaller proportions and simulating the policies on these smaller segments. Thus, users would see how their decisions would affect these specific segments in the highway network over a period of time. Furthermore, DES technique would better model the multiple resource requirements and dynamic complexity of pavement maintenance processes. The purpose for this research is to create a decision support tool utilizing discrete event simulation technique where the highway maintenance managers can foresee the outcomes of their what-if scenarios on the specific segments and whole of the highway network evaluated. Thus, can be used for both project and network level decision support. The simulation can also be used as a guiding tool on when, where and why resources are needed on needs basis. This research relies on the budget allocation results from the linear optimization model (LOM). This model is a tool that creates the optimized budget allocation scheme for a network fitting to a determined scenario. Thus by integrating the LOM and the DES model, the maintenance managers can acquire an optimized budget allocation for their district and evaluate the results in both network and project selection level. Maintenance managers can obtain the best budget allocation plan without performing the repetitive trial and error approach like the previous decision support tools. There is a vast amount data in many varieties gathered as results from the simulation model. This fact alone demonstrates how powerful the discrete event simulation model is. By the nature of this simulation technique, the resources (highway segments, annual budget) can be traced throughout the simulation and this trait allows the design of the project selection level decision support system. By examining these reports, the maintenance managers can better observe how the scenarios evolve. Thus this tool helps the maintenance managers to have better decisions on the project selection level. The discrete event simulation model established in this research carries the project selection level pavement management from a position where maintenance managers should solely depend on their engineering judgment and experience to a position where maintenance managers can have more effective and justified plans since they can foresee the results of these decisions on the segments that are forming the network. This simulation engine is created with the discrete event simulation language called STROBOSCOPE. The model consists of two parts which work like a lock and key mechanism. The first part of the model is the data feeding mechanism where information from any network is loaded. The second part is the generic engine which can evaluate any road network data it is fed. The purpose of segregating these two components of the model is to allow the user to evaluate any network regardless of length, number of segments or the location.
Master of Science

This dissertation is concerned with the principles of pavement management systems and their applications in western and developing countries. The first part of the dissertation deals with the principles of pavement engineering and the role of the different layers in order to gain the required knowledge in highway pavement components, which will allow a cost-effective repair related to each specific defect. The second part deals with the existing systems for monitoring pavement condition and evaluatest heir benefit in assessingh ighway condition. The study shows the main problems usually militate against using the sophisticated technology in monitoring highway condition and implementing maintenance management systems in some cities in developing countries. In addition to the problems inherent in cities in developing countries, the city of Benghazi in Libya has special factors which have developed as a result of UN sanctions which were imposed in 1992. Therefore, the city of Benghazi has been selected as a case study for this particular research since it is a typical example of most cities in developing countries in terms of size, population and in ten-ns of lack of maintenance resources and skilled labour (Benghazi might have been so well resourcedth at it would no longer fall into the categoryo f developingc ity but for the sanction). The objectives of the study are attained through conclusions which indicate that establishing a pavement maintenance strategy in the city of Benghazi based on any or some of the sophisticated technology in road condition monitoring is not appropriate. This conclusion is tested by manufacturing a unique prototype measuring machine and using it in pilot monitoring exercises in the cities of Newcastle and Sunderland. The results of these pilot exercises are analysed to evaluate the benefit which such appropriate technology equipment can bring to the issue of monitoring of pavement condition in cities in developing countries having problems similar to those that prevail in Benghazi. The prototype equipment developed in this study is unique in that it is purely mechanical and uses no electronics in monitoring road condition. Moreover, all parts of the machine are fabricated from materials available in most cities in developing countries and therefore such machines could be easily maintained locally. The prototype described in this study is not only relevant to road monitoring but points the way towards the development of similar equipment in many engineering situations in developing countries. This research study points engineers in similar conditions in the direction that the Author thinks they should follow in applying their engineering abilities in developing countries.

This research sought to integrate measurement and prediction of surface macrotexture for use in pavement management systems. This was achieved through two experiments, the first modeled the behavior of a binder-rich stone matrix asphalt when subjected to traffic loading using a heavy vehicle simulator to report the effect on pavement macrotexture. The second experiment compared high-speed macrotexture measurement devices on a variety of surfaces and under various operating conditions. The change in macrotexture due to traffic loading showed that as the cumulative load increased, the macrotexture decreased due to bleeding on the pavement's surface. A regression model determined that, on average, the macrotexture's root mean square (RMS) decreased 0.14 mm per million equivalent single axle load applied. A comparison of RMS and mean profile depth (MPD) outputs indicated that RMS was more sensitive to changes in macrotexture due to bleeding. In comparing devices, pairwise device agreement was evaluated using a Limits of Agreement. The results demonstrate good repeatability for each of the devices tested. The agreement analysis showed that not all high-speed devices can be used interchangeably for all pavement surfaces. Data acquisition speed was found to be a factor in macrotexture parameter calculation for two of the devices. The effect of speed was found to be worse on randomly textured surfaces than on transversely textured surfaces.
Master of Science
This thesis sought to integrate the collection and prediction of a pavement surface property known as macrotexture for use in the management of pavement networks. This was achieved through two experiments, the first of which modeled the behavior of asphalt concrete with a higher than typical asphalt content when subjected to simulated traffic to determine the effect on pavement macrotexture. The second experiment compared five high-speed macrotexture measurement devices on a variety of pavement surface types and under various operating conditions. The change in macrotexture due to traffic loading showed that as the cumulative traffic increased, the macrotexture decreased due to the asphalt coming out on the surface, referred to as bleeding. For the comparison of measurement devices data were processed using current industry standards. The results demonstrate good repeatability for each of the devices tested. The analysis also showed that not all high-speed devices can be used interchangeably for all pavement surface types. Vehicle speed was found to be a factor for two of the devices. The effect of speed was found to vary by surface type. Finally, vehicle acceleration was shown to influence the parameters produced by one of the devices, demonstrating that care should be taken to gather high-quality datasets for the critical pavement characteristic of macrotexture.

In urban areas, trees are often planted in bare soil sidewalk openings (tree pits) which recently are being covered with permeable pavements. Pavements are known to alter soil moisture and temperature, and may have implications for tree growth, root development and depth, drought resilience, and sidewalk lifting. Furthermore, tree pits are often the only unsealed soil surface and are important for water exchange between soil and atmosphere. Therefore, covering tree pits with pavement, even permeable, may have implications for the urban water balance and stormwater management. A better understanding of permeable pavement on tree pavement soil system functioning can inform improved tree pit and street design for greater sustainability of urban environments. We conducted experiments at two sites in Virginia, USA (Mountains and Coastal Plain) with different climate and soil. At each location, we constructed 24 tree pits in a completely randomized experiment with two factors: paved with resin-bound porous-permeable pavement versus unpaved, and planted with Platanus x acerifolia 'Bloodgood' versus unplanted (n = 6). We measured tree stem diameter, root growth and depth, and soil water content and temperature over two growing seasons. We also monitored tree sap flow one week in June 2017 at the Mountains. In addition, we calibrated and validated a soil water flow model, HYDRUS-1D, to predict soil water distribution for different rooting depths, soil textures and pavement thicknesses. Trees in paved tree pits grew larger, with stem diameters 29% (Mountains) and 51% (Coastal Plain) greater. Roots developed faster under pavement, possibly due to the increased soil water content and the extended root growing season (14 more days). Tree transpiration was 33% of unpaved and planted pit water outputs, while it was 64% for paved and planted pits. In June 2016, planted pits had decreased root-zone water storage, while unplanted pits showed increased storage. A water balance of the entire experimental site showed overall decreased soil water storage due to tree water extraction becoming the dominant factor. HYDRUS-1D provided overall best results for model validation at 10 cm depth from soil surface (NSE = 0.447 for planted and paved tree pits), compared to 30- and 60 cm depths. HYDRUS-1D simulations with greater pavement thickness resulted in changes in predicted soil water content at the Coastal Plain, with higher values at 10- and 30-cm depths, but lower values at 60-cm depth. At the Mountains, virtually no difference was observed, possibly due to different soil texture (sandy vs clayey). Tree pits with permeable pavement accelerated tree establishment, but promoted shallower roots, possibly increasing root-pavement conflicts and tree drought susceptibility. Paved tree pits resulted in larger trees, increasing tree transpiration, but reduced soil evaporation compared to unpaved pits. Larger bare soil pits surrounded by permeable pavement might yield the best results to improve urban stormwater retention. Also, HYDRUS 1D was successful at simulating soil water content at 10-cm depth and may be valuable to inform streetscape design and planning.
PHD

Planning road maintenance and development activities, prioritizing road construction, reconstruction and rehabilitation works, performing project economic evaluations, forecasting road operation expenditures and road user effect always requires prediction of pavement behaviour. For this purpose models of pavement deterioration are used. Commonly they are integrated in more sophisticated computational systems, known as Pavement Management systems (PMS) and Highway Development and Management systems (HDM). The implementation of these systems started in Lithuania shortly after the Re-establishment of the Independence. This was triggered by the violent drop in financing of the road sector, forcing to change obsolete road management strategy and planning approach. The need for project economic evaluations, transport modelling and long term pavement performance forecasts grew up after Lithuania joined the European Union and this brought the opportunity for financing road infrastructure projects from the EU funds. At present only on the Lithuanian state road network the total value of implemented projects, justified by evaluations and modelling with PMS, amounts to about 500 million Litas annually. Any Pavement Management System is just as good as the models within it, used for pavement deterioration prediction. The performed test calculations show that prediction models, currently used for this purpose in PMS we have in Lithuania, are of doubtful accuracy and have to be improved... [to full text]

Road authorities around the world have been innovating and finding ways to cope with the high cost of road network maintenance, the growing demands of road users and the changing traffic type and volume. A well-maintained road is needed to make the network sustainable for future generations. Improving road maintenance management in the Philippines, based on New Zealand experience, is the goal of this research with the theme of managing the change from method-based specifications to the adoption of performance-based specifications for unsealed low-volume roads. The New Zealand Local Government Act 2002 prescribes the requirements for the provision, operation, and management of the local road network, consistent with the Land Transport Management Act 2002 and the New Zealand Land Transport Strategy. The maintenance management system used by New Zealand road controlling authorities (RCAs) was determined by survey and a profile of RCAs that have adopted performance-based specifications was established. RCAs that adopted performance-based specifications had employed asset managers, used the Road Asset Maintenance Management (RAMM) system as an asset management tool, engaged consultants for specialised skills, employed more engineers, had highly developed performance specifications, conducted customer surveys, and had more resources in terms of rates and revenues than RCAs that had not adopted performance-based specifications. The proposed performance-based specifications for sealed and unsealed roads were also presented in this thesis. The Department of Public Works and Highways of the Philippines has implemented three long-term performance-based maintenance pilot projects, all completed by 2005. The lessons learned from the pilot projects, together with the New Zealand survey results will guide road authorities in the Philippines to improve the implementation of future long-term performance-based maintenance contracts (LTPBMC) on national roads, and possibly apply the same to low-volume roads.

Os modelos de previsão de desempenho são ferramentas fundamentais em um Sistema de Gerência de Pavimentos. Embora de grande importância, especificamente no Brasil, tem-se dado pouca atenção para a calibração e validação desses modelos. Acaba-se adotando modelos genéricos, obtidos em condições totalmente diferentes das existentes na malha administrada. Para uma gerência correta dos pavimentos de uma rodovia, torna-se fundamental a definição de modelos representativos das condições estruturais e funcionais dos pavimentos administrados. Esta pesquisa tem como objetivo avaliar o desempenho de uma estrutura de pavimento flexível da rodovia BR-290/RS, desenvolvendo, a partir dessa avaliação, modelos que representem a tendência do comportamento do pavimento. A rodovia BR-290/RS está, no trecho entre as cidades de Osório e Porto Alegre, sob concessão da Concessionária da Rodovia Osório - Porto Alegre S/A - Concepa, desde o ano de 1997. Uma das principais ações a serem realizadas pela concessionária no período em que este trecho da rodovia está sob sua administração é a execução do alargamento das pistas da mesma, com a construção de uma nova estrutura de pavimento junto à plataforma existente, sendo essa a estrutura de pavimento analisada nesta pesquisa. A estrutura contempla 8cm de revestimento asfáltico, 15cm de base, 30cm de sub-base e 60cm de camada de reforço. Os pavimentos inseridos na análise foram construídos entre os anos 2000 e 2007. Para atingir o objetivo da pesquisa, foram reunidas informações obtidas em levantamentos de deflexões, irregularidade longitudinal e afundamento de trilha de roda realizados nos últimos anos. As deflexões foram determinadas em levantamento com o equipamento FWD ocorrido em 2007. A irregularidade longitudinal e o afundamento de trilha de roda foram obtidos simultaneamente em levantamentos com o perfilômetro a laser nos anos 2005, 2006 e 2007. De posse dessas informações, analisou-se o comportamento de tais parâmetros com a ação do tráfego, desenvolvendo tendências de desempenho para a estrutura. Na análise considerou-se a influência das intervenções ocorridas nos pavimentos após a sua construção, bem como diferentes procedimentos adotados nos levantamentos realizados. Em relação às intervenções, verificou-se que, para a estrutura e dados do estudo, elas foram influentes apenas na evolução da irregularidade longitudinal. Análises estatísticas foram efetuadas, de modo a definir o melhor ajuste para cada parâmetro. Após o desenvolvimento de tais tendências de comportamento do pavimento, as mesmas foram comparadas aos modelos de previsão de desempenho desenvolvidos em outras pesquisas. Para a irregularidade e o afundamento de trilha de roda, as tendências apresentadas neste estudo comportaram-se significativamente semelhantes as de outros modelos encontrados na bibliografia técnica. Por outro lado, para a tendência referente às deflexões, nenhum dos modelos desenvolvidos em estudos anteriores apresentou comportamento similar ao encontrado na pesquisa, evidenciando a importância do desenvolvimento de modelos particulares para cada rodovia e estrutura.
Pavement performance prediction models are important tools for pavement management systems. Despite its high importance, specifically in Brazil, little attention has been given to calibration and validation of such models. Generic models are eventually used, even international ones, obtained for rather different conditions of those valid for the managed network. Hence, it is vital for an appropriate road pavement management that representative models of the structural and functional conditions of the associated pavements are defined. This research aims to evaluate the behaviour of the performance of a flexible pavement section of the road BR-290/RS, developing from this assessment, models that are representative of the pavement behaviour tendency. The road BR-290/RS is located between the cities of Osório and Porto Alegre, under concession of Concessionária da Rodovia Osório - Porto Alegre S/A - Concepa, since the year of 1997. One of the main actions to be accomplished by the road concessionary within the period under its administration is the carriageway widening of this road with the construction of a new pavement structure alongside, being this structure the objective of study in this research. The structure consists of an asphaltic layer of 8cm, 15cm of base course, 30cm of sub-base and 60cm of a capping layer. The pavement segments included in the analysis were built between 2000 and 2007. To deliver the objectives of this research, data obtained in deflectometric test campaigns, longitudinal roughness and rutting testing campaigns were gathered. Deflections were assessed in the FWD test campaign of 2007. Longitudinal roughness and rutting were simultaneously obtained with a laser profilometer in tests carried out in the years of 2005, 2006 and 2007. With this data, the behaviour of these parameters were evaluated with the traffic evolution, allowing the development of behaviour tendencies of this structure performance to be derived. In the analysis, the influence of the interventions carried out in the pavement sections after its construction were taken into account, as well as different procedures adopted in the testing campaigns carried out. In regard to the interventions, it was observed that, for the data and structure object of this study, they only had effect in the longitudinal roughness evolution. Statistical analyses were carried out in order to define the best adjustment to each parameter. After the development of such tendencies on the pavement behaviour, they were compared to pavement performance prediction models developed in other researches. For both roughness and rutting, the tendencies presented in the study behaved significantly as the other models found in the technical literature. As to the tendencies regarding deflections, none of the models developed in previous studies evidenced similar behaviour to the one observed in this research, testifying the importance for the development of particular models for each road and structure.

O número de concessões rodoviárias tem aumentado em todo o mundo. Somente no Brasil, desde 1995, três etapas de concessão já foram realizadas pelo governo federal. No estado de São Paulo, as concessões estão em sua segunda etapa. Uma das principais justificativas para as concessões rodoviárias é a melhoria da condição dos pavimentos. Sendo assim, este trabalho buscou avaliar os benefícios oriundos da melhor conservação dos pavimentos, em termos da irregularidade longitudinal, diretamente relacionada com os custos de operação dos veículos (custos dos usuários: consumo de combustível, desgaste de pneus, tempo de viagem etc.), comparando com os custos por pagamento de pedágio. Para tanto, foram selecionados, através da análise de cluster, três trechos distintos, de tal forma que se tivesse, pelo menos, um segmento do modelo da ANTT da primeira etapa, um segmento do modelo da ANTT da segunda etapa e um segmento do modelo da ARTESP. Os custos de operação dos veículos foram determinados com uso do software HDM-4 e a análise econômica considerou o Valor Presente Líquido (VPL), a Taxa Interna de Retorno (TIR) e a Relação Benefício/Custo (B/C). As alternativas consideradas na análise simularam as exigências contratuais presentes no programa CREMA e no Programa de Exploração da Rodovia (PER) da ANTT. A condição \"base\" para as análises simulou um cenário limite para intervenção no pavimento, onde a mesma só ocorria com irregularidades muito elevadas. Após a realização das simulações, concluiu-se que o método do VPL era o mais adequado para as análises, pois todos os trechos apresentaram custos aos usuários maiores do que os benefícios observados. Ao se realizar análise complementar, com limites de irregularidade ainda maiores para a condição \"base\", somente o modelo da ANTT da segunda etapa justificou economicamente a concessão, do ponto de vista dos usuários. Conclui-se, portanto, que existem evidências de que as concessões rodoviárias no Brasil não têm melhorado a condição dos pavimentos a ponto de ser justificada economicamente, decorrendo a sugestão para que as próximas concessões acarretem custos de pedágio menores ou apresentem um maior número de obras com impacto significativo na redução do tempo de viagem e no aumento da segurança dos usuários.
The number of road concessions has increased worldwide. Only in Brazil, since 1995, three concession stages have already been carried out by the federal government. In the state of São Paulo, the concessions are in its second stage. One of the main justifications for road concessions is the improvement of pavement condition. Therefore, this study sought to evaluate the benefits of better pavement conservation in terms of longitudinal roughness, directly related to vehicle operating costs (user costs: fuel consumption, tire wear, travel time, etc.), comparing it to toll payment costs. In order to do so, three distinct sections were selected through the cluster analysis, so that there was at least one segment of the ANTT model of the first stage, a segment of the ANTT model of the second stage and a segment of the model of ARTESP. Vehicle operating costs were determined using the HDM-4 software and the economic analysis considered the Net Present Value (NPV), the Internal Rate of Return (IRR) and the Benefit/Cost Ratio (B/C). The alternatives considered in the analysis simulated the contractual requirements present in the CREMA program and in the ANTT Highway Exploration Program (HEP). The \"base\" condition for the analyzes simulated a limit scenario for intervention in the pavement, where it only occurred with very high roughness. After the simulations, it was concluded that the NPV method was the most appropriate for the analyzes, since all the stretches presented costs to users greater than the observed benefits. When performing complementary analysis, with even greater limits of roughness for the \"base\" condition, only the ANTT model of the second stage economically justified the concession, from the users point of view. It is concluded, therefore, that there is evidence that the road concessions in Brazil have not improved the condition of the pavements to the point of being economically justified, suggesting that the next concessions bring lower toll costs or present a greater number of works with significant impact on reducing travel time and increasing user safety.

Neste trabalho são analisados os Sistemas de Gerência de Pavimentos Urbanos (SGPU) e os Sistemas de lnformação Geográfica (SIG) visando a obtenção de formas com que possam ser aplicados para a compatibilização das atividades de gerência de todas as redes de infra-estrutura pública urbana (pavimento, água, esgoto, telefone, gás, energia elétrica). Desenvolve-se um projeto piloto, utilizando o aplicativo de SIG TransCAD para a gerência de pavimentos sob duas condições: na primeira, através de uma interface com um programa de gerência de pavimentos urbanos já em utilização (URMS, desenvolvido na Universidade do Texas em Austin); na segunda, como plataforma para o desenvolvimento de um novo sistema de gerência de pavimentos, tanto em nível de rede como em nível de projeto. São utilizadas bases de dados para o pavimento e para a rede de água de abastecimento, criadas para a análise de viabilidade da compatibilização da gerência de pavimentos com as atividades de concessionárias de serviços públicos urbanos, a qual confirmou a grande potencialidade do uso dos Sistemas de Informação Geográfica para a gerência integrada e racional da infra-estrutura pública urbana.
This work presents studies about Urban Pavement Management Systems (U-PMS) and Geographic lnformation Systems (GIS) aiming their utilization as a tool for the harmonization of urban infrastructure (pavement, gas, electric power, sewer, water, telephone) maintenance and rehabilitation activities. lt is developed a pilot study using the SIG software called TransCAD for pavement management under two conditions: the first one, through an interface with an already in use pavement management system (URMS, developed at the University of Texas at Austin); the second one, as a framework for the development of a new pavement management system, at network and project levels. Data bases for pavement and water networks are used for analysis of the harmonization of pavement management with other public infrastructure activities, which confirmed the great power of GIS for utilization in a rational and integrated urban infrastructure management system.

A presente pesquisa objetiva contribuir para a implantação de Sistemas de Gerência de Pavimentos Aeroportuários (SGPA), tendo por base um estudo de caso desenvolvido no Aeroporto Estadual de Araraquara-SP Bartolomeu de Gusmão. Foi criado um banco de dados informatizado, através do FAA PAVEAIR, programa computacional de gerência de pavimentos aeroportuários disponibilizado pelo FAA (Federal Aviation Administration), que permitiu o armazenamento de toda informação inerente aos pavimentos do complexo aeroportuário e a determinação, com base no método PCI (Pavement Condition Index), da condição atual da pista de pousos e decolagens, da pista de rolagem e do pátio de aeronaves. Os resultados mostraram que o aeroporto de Araraquara apresenta condição regular de operação, indicada por um PCI médio de 67, e que os principais defeitos encontrados foram desagregação das partículas da mistura asfáltica, trincas transversais e, principalmente, trincas longitudinais. Por conseguinte, foram planejadas intervenções de manutenção e reabilitação, de modo a evitar situações que levassem ao comprometimento geral da condição dos pavimentos e, por consequência, a um aumento significativo dos custos de conservação. A melhor estratégia, se aplicada ao longo dos vinte anos de período de projeto, resultaria em um valor de PCI médio igual a 77, correspondente a boas condições de operação. Dessa forma, o estudo de caso desenvolvido contribuiu, com um exemplo completo, para a implantação de um SGPA em nível de rede e, mais ainda, para o desenvolvimento de um SGPA integral para a rede de aeroportos de administrações aeroportuárias de pequeno, médio e grande portes no Brasil, o que deve ser precedido pela elaboração de legislação específica que exija a aplicação efetiva de técnicas de manutenção que prolonguem a vida útil dos pavimentos, especialmente devido ao aumento da demanda por transporte aéreo e à necessidade de modernas e potentes aeronaves, que requerem, cada vez mais, melhores condições funcionais e estruturais das pistas de pousos e decolagens e dos pátios de aeronaves dos aeroportos.
This research aims to contribute to the implementation of Airport Pavements Management Systems (SGPA), based on a case study developed at the Araraquara State Airport Bartolomeu de Gusmao, in the State of Sao Paulo, Brazil. A computerized database was created, using the FAA PAVEAIR, an airport pavement management computer program provided by the FAA (Federal Aviation Administration), which allowed the storage all information inherent to the airport complex facilities and determining, based on the method of PCI (Pavement Condition Index), the current condition of the runway, taxiway and apron. The results showed that the airport presents regular operating condition, indicated by an average PCI of 67, and that the main defects found were raveling, transverse cracks and mainly longitudinal cracks. Therefore, maintenance and rehabilitation operations are planned so as to avoid situations that could lead to impairment of the general condition of the pavement and, consequently, a significant increase of maintenance costs. The best strategy, if applied over the twenty-year project period, would result in average PCI value of 77, corresponding to good operating condition. Thus, the case study developed contributed with a complete example, for the implementation of a SGPA network-level and even more so for the development of a comprehensive SGPA to the airport network of administrations of small, medium and large airports in Brazil, which should be preceded by the enactment of specific legislation that requires the effective application of maintenance techniques that prolong the life of pavements, especially due to increased demand for air transport and the need for modern and powerful aircraft, requiring increasingly, better functional and structural conditions of runways and aprons.

Pavement Management Systems (PMS) are widely used by transportation agencies to maintain safe, durable and economic road networks. PMS prioritize the maintenance and rehabilitation of pavement sections by evaluating pavement performance at the network level. There are many PMS software packages that have been developed over the past decades for provincial/state road agencies. However, sometimes due to lack of budget and experience, adopting the existing PMS for a road agency is not cost effective. Thus, it is important to introduce a simple, effective, and affordable PMS for a local agency and municipality. This research is carried out in partnership between the City of Markham and the Centre for Pavement and Transportation Technology (CPATT) located at the University of Waterloo. For the purpose of developing a PMS for local agencies, an extensive literature review on PMS components was carried out, with emphasizing data inventory, data collection, and performance evaluation. In addition, the literature review also concentrated on the overall pavement condition assessment. In July 2011, a study on “Evaluation of Pavement Distress Measurement Survey” was conducted as a part of this research and was distributed to cities and municipalities across Canada. The study focused on the current state-of-the-practice in pavement distress and condition evaluation methods used by local agencies to compare the results from the literature review. The components of the proposed PMS framework are also developed based on the literature review with some modifications and technical requirements. The City of Markham is selected as a case study, since it represents a local agency and provides all the data, to illustrate the validation of the proposed PMS framework.

Thesis. (M. Tech. (Faculty of Engineering and Technology, Dept. of Civil Engineering))--Vaal University of Technology, 2011
In the past thirty years there has been a rapid deterioration of the road network in South Africa. As an attempt to address this challenge, a study was conducted on R34 between Vrede and Bothmas Pass Border. The aim of the study was to develop a pavement management system for road network maintenance to serve as a decision support tool to assist to improve the efficiency of making decisions, provide feedback as to the consequences of these decisions, ensure consistency of decisions made at different levels and improve the effectiveness of all decisions in terms of efficiency of results. The study focused on developing and testing pavement management system for road network maintenance. Consequently, visual condition inspections, non-destructive and semi-destructive tests were conducted on the field, data acquired, processed and analysed in accordance with guidelines stipulated in the Draft Technical Recommendations for Highways (TRH) 22 in order to draw conclusions. The data acquired included the surfacing assessments, structural assessments, functional assessments, traffic surveys, riding quality, falling weight deflectometer, mechanical rutting, material investigations and dynamic cone penetration. After analysis of the data, visual condition index was then calculated to be 40%. Visual condition index was then used to determine the action required towards rehabilitating the road. After consultation with guidelines contained in the TRH22, it was concluded that the pavement treatment needed for the road was Rehabilitation. It was then concluded that PMS developed would provide key performance indicators to assist with decision support system and that it is also suitable for road network applications ranging from national roads, provincial roads, regional or district arterial and collector / distributor networks in SA. The municipalities and other road maintenance agencies were then recommended to utilise the “easy to use” developed pavement management system as a decision support tool in their maintenance programmes.

Doctoral Thesis in Civil Engineering
The expansion and quality increase of road infrastructures in developed countries during the last decades is shifting the attention towards their preservation rather than to new construction. Pavements are the most costly road asset. Therefore, their preservation management optimization is important in order to meet quality and safety demands within available budgets that are becoming increasingly limited. More recently, environmental aspects related to the pavements life-cycle have been raising concerns that must be addressed. The present thesis describes the development of an optimization methodology that intends to be a decision support tool for road administrations. In fact, this work emerged within the scope of a highway administration related project, so it has a character of applied research. The developed methodology is capable of suggesting pavement preservation plans at the network level for a certain time period. It considers aspects related to pavement quality, administration costs, as well as user and environmental costs. Genetic algorithms are employed to optimize problems with two or three con icting objectives, either simultaneously or at distinct phases in order to deal with pairs of objectives at di erent levels. Data selection and ltering and the development of Markov based prediction models are also included in the thesis. The methodology is exible, so that other prediction models with better adjustment to the problem to be solved can be implemented. Similarly, preservation operations and the respective costs and e ects on the pavement are also adjustable. The use of European-level standardized performance indicators and the consideration of user costs and costs related to CO2 emissions in a multi-objective optimization are the main di erences of this methodology to existent ones. The methodology is applied in two distinct case studies that complement each other, allowing to demonstrate the features and adaptability of the methodology. The rst case study relies on historical data from an American database, while the second one is based on data provided by a Portuguese highway administration. In the rst case, preservation plans for a group of geographically separated pavement sections are de ned, regarding administration costs and pavement quality at rst, and user and environmental costs at last. The second case study is focused on a pavement segment that is divided in several dozens of adjacent sections. This allows the suggestion of preservation plans indicating the relative segment area that should be a ected with a speci c treatment in a speci c year, in order to meet quality constraints while optimizing administration costs and pavement quality for the analysis period.
O grande desenvolvimento verificado na expansão e na qualidade das infraestruturas rodoviárias nas últimas décadas em países desenvolvidos, faz com que cada vez seja dada mais atenção à sua preservação do que à nova construção. Os pavimentos rodoviários são o ativo mais dispendioso das estradas, pelo que é de extrema importância otimizar a gestão da sua conservação de modo a cumprir com critérios de qualidade e segurança dentro dos limites orçamentais que tendem a ser cada vez mais restritos. Mais recentemente, questões ambientais associadas ao ciclo de vida dos pavimentos rodoviários têm levantado preocupações que devem ser abordadas. Esta tese descreve o desenvolvimento de uma metodologia de otimização que pretende constituir uma ferramenta de apoio à decisão para administrações rodoviárias. De facto, este trabalho surgiu no âmbito de um projeto associado a uma concessionária de auto-estradas, pelo que tem um caracter de investigação aplicada. A metodologia desenvolvida é capaz de sugerir planos de conservação de pavimentos ao nível da rede para um determinado período de tempo, tendo em conta aspetos relacionados com a qualidade do pavimento, custos para as concessionárias, bem como custos para os utentes da estrada e para o ambiente. A metodologia usa algoritmos genéticos para otimizar problemas com dois ou três objetivos conflituantes, quer em simultâneo, quer em fases distintas de modo a lidar com pares de objetivos em diferentes níveis. A tese inclui ainda uma etapa de seleção e tratamento de dados, bem como de desenvolvimento de modelos de previsão baseados em cadeias de Markov. A metodologia é exigível e pode ser alimentada com outros modelos de previsão que melhor se ajustem ao problema em causa. De igual modo, também as operações de conservação, respetivos custos e efeitos no pavimento são ajustáveis. O uso de indicadores de desempenho uniformizados ao nível Europeu, e a inclusão de custos para os utilizadores das estradas e de custos associados a emissões de CO2 numa otimização multi-objectivo são as principais diferenças desta metodologia para outras já existentes na literatura. A metodologia é aplicada a dois casos de estudo distintos que se complementam e permitem demonstrar as funcionalidades e flexibilidade da metodologia. O primeiro caso de estudo baseia-se em dados históricos de uma base de dados Americana, e o segundo em dados fornecidos por uma concessionária de autoestradas Portuguesa. No primeiro caso, são definidos planos de conservação para um conjunto de secções de pavimento separadas geograficamente, tendo em conta custos para a administração e qualidade do pavimento, primeiramente, e custos ambientais e para o utilizador, por último. O segundo caso de estudo foca-se numa extensão de pavimento dividida em várias dezenas de secções adjacentes, permitindo assim definir planos de conservação que indicam percentagens dessa extensão que deverão receber um determinado tratamento em determinado ano, de modo a otimizar a qualidade e os custos para a concessionária, cumprindo com as restrições de qualidade para todo o período de análise.
This research work was nanced by the Ministry of Education and Science of the Government of Portugal and by the European Social Fund of the European Union (ESF/EU) through the Foundation for Science and Technology (FCT) with the Ph.D. grant SFRH/BD/85984/2012.

Die Straßeninfrastruktur ist die wichtigste Grundlage für die Mobilität von Wirtschaft und Gesellschaft und stellt ein großes Anlagevermögen für Bund, Bundesländer, Landkreise und Gemeinden dar. Aufgrund der hohen Beanspruchungen aus Verkehr und Witterung ist die Infrastruktur kontinuierlich durch geeignete Maßnahmen zu erhalten. Die Erhaltungsplanung wurde in den vergangenen Jahren stärker systematisiert. Auf Netzebene werden durch die „Richtlinien für die Planung von Erhaltungsmaßnahmen an Straßenbefestigungen“ (RPE-Stra 01 - FGSV 2001a) Verfahren beschrieben, um an formulierten Zielen ausgerichtete und strategische Erhaltungsprogramme aufzustellen. Zur Darstellung netzweiter Strategieszenarien werden heutzutage Pavement-Management-Systeme (PMS) eingesetzt. Sie ermitteln diejenigen Erhaltungsmaßnahmen, die bei vorgegebenem Betrachtungszeitraum und Mitteleinsatz den maximalen Nutzen (Verbesserung des Straßenzustands) versprechen. Die Erhaltungsmaßnahmen können hinsichtlich ihres Umfangs nach Maßnahmen der Instandsetzung und Erneuerung differenziert werden. Der verbesserte Fahrbahnzustand und der Eindruck einer neuen, richtliniengerechten Straße, der speziell bei Erneuerungsmaßnahmen entsteht, führt erfahrungsgemäß zu höheren Geschwindigkeiten der Verkehrsteilnehmer (WEISE 1991). Diese geschwindigkeitserhöhende Wirkung ist insbesondere auf Landstraßen kritisch zu prüfen. Die Landstraßen in der Bundesrepublik Deutschland sind in ihrer Gestaltung sehr heterogen. Aus Netzergänzungen, den Bau von Ortsumgehungen und grundlegenden Modernisierungen sind sukzessive Streckenabschnitte entstanden, die den Anforderungen aktueller Regelwerke hinsichtlich Verkehrssicherheit und Leistungsfähigkeit genügen. Demgegenüber existieren Straßen, deren Linienführung aus den Anfängen des motorisierten Individualverkehrs stammt und die im Zuge von Erhaltungsarbeiten nur ungenügend an die Entwurfsparameter der entsprechenden Regelwerke angepasst wurden. Sie entsprechen oft nicht dem Stand der Technik. Diese Tatsache spiegelt sich auch im Unfallgeschehen wider. Etwa 57 % der Verkehrstoten sind auf Landstraßen zu verzeichnen (DESTATIS 2017). Diese besondere Unfallschwere ist u. a. auf das instabile Verhältnis von dem vorhandenen Geschwindigkeitsniveau zu der Güte der Gestaltung zurückzuführen. Nicht angepasste Geschwindigkeit ist außerorts die Hauptunfallursache bei Unfällen mit Getöteten (DESTATIS 2017). Die Unfallstatistik unterstreicht also die Bedeutung, entwurfstechnische Belange auch im Zuge von Erhaltungsmaßnahmen zu berücksichtigen. Trotz dieser besonderen Bedeutung werden die entwurfs- und sicherheitstechnischen Belange bei der Erhaltungsplanung noch nicht hinreichend berücksichtigt. Ziel der vorliegenden Arbeit war es daher, ein Verfahren zu entwickeln, welches die Geometrie eines Straßennetzes bewertet und - daraus abgeleitet - entsprechende Kriterien für die Integration in Pavement-Management-Systeme definiert. Um darauf aufbauend entwurfstechnische Um- und Ausbauempfehlungen wirksam in das PMS zu implementieren, war die derzeitige Nutzendefinition um sicherheitstechnische Aspekte weiterzuentwickeln. Dazu waren zunächst die maßgebenden Entwurfsmerkmale abzugrenzen. In diesen Untersuchungen haben sich vor allem die Fahrbahnbreite und die Größe/Abfolge der Lageplanelemente als sicherheitsrelevant herausgestellt. Fahrbahnbreiten von 7,00 m ≤ B ≤ 8,50 m sind - ähnlich wie bei VIETEN U. A. (2010) - durch ein geringeres Unfallgeschehen gekennzeichnet. Dieser Sicherheitsvorteil breiterer Querschnitte wurde insbesondere bei nicht relationstrassierten Streckenabschnitten festgestellt. Es zeigte sich jedoch, dass die Belange der Linienführung im Lageplan stärker auf die Verkehrssicherheit wirken als die Querschnittsgestaltung. Relationstrassierte Strecken wiesen unabhängig von der Fahrbahnbreite durchschnittlich nur halb so hohe Unfallkennwerte auf wie nicht relationstrassierte Straßenabschnitte. Zur Bewertung der Relationstrassierung hat sich das Maß der Abweichung von den Forderungen der RAL (FGSV 2012a) als geeignetes Kriterium herausgestellt. Bei einer prozentualen Abweichung von Abw > 25 % stiegen in den vorliegenden Streckenkollektiven die Unfallkennwerte sprunghaft an. Anhand dieser Ergebnisse wurde ein Verfahren zur entwurfstechnischen Bewertung von Straßennetzen erarbeitet. Das Verfahren basiert auf einem dreistufigen Bewertungssystem, welches das Maß der Abweichung von den Entwurfsrichtlinien beschreibt. Im Ergebnis werden allgemeine Empfehlungen zur Anpassung der Linienführung in Abhängigkeit vom Längenanteil sicherheitskritischer Kurven an der Gesamtlänge des Straßenabschnitts formuliert. Die Empfehlungen für entwurfstechnische Maßnahmen können über sogenannte Anwendungsbereiche bei der strategischen Erhaltungsplanung mittels PMS berücksichtigt werden. In Abhängigkeit vom Längenanteil sicherheitskritischer Kurvenbereiche sind nur bestimmte Erhaltungsmaßnahmen zulässig. Damit können höherwertige (und somit geschwindigkeitserhöhende) Maßnahmen der baulichen Erhaltung bei Straßenabschnitten mit unzureichender geometrischer Gestaltung ausgeschlossen bzw. abgegrenzt werden. Diese Bereiche sind in der Linienführung elementweise bzw. gänzlich anzupassen. Entsprechende Um- und Ausbaumaßnahmen waren daher im letzten Schritt wirksam in das PMS zu integrieren. Den erfahrungsgemäß höheren Kosten dieser Maßnahmen steht der zu erwartende volkswirtschaftliche „Gewinn“ infolge vermiedener Straßenverkehrsunfälle gegenüber. Daher wurde die Definition des Nutzens bei Um- und Ausbaumaßnahmen um einen Wichtungsfaktor erweitert, welcher das tatsächliche Unfallgeschehen der jeweiligen Straßenabschnitte berücksichtigt. Mit dem entwickelten Verfahren können bei der strategischen Erhaltungsplanung nun entwurfstechnische Belange ebenfalls berücksichtigt werden. Die aus den Sicherheitsuntersuchungen abgeleiteten Parameter und Kriterien orientieren sich an der Grundstruktur der Straßendatenbanken. Damit ist es möglich, bestehende PMS-Module anzupassen sowie ein eigenständiges Modul „Um- und Ausbau“ zu entwickeln und in das Gesamtsystem zu implementieren. Die erforderliche Datengrundlage ist zum Teil bereits in den Straßendatenbanken vorhanden bzw. kann mit vertretbarem Aufwand berechnet werden. Bei konsequenter Anwendung des Verfahrens wird sich die Sicherheit auf Landstraßen mittel- und langfristig verbessern.:1 Einleitung 2 Stand von Wissenschaft und Technik 2.1 Sicherheitstechnische Aspekte bei der Festlegung von Entwurfselementen 2.1.1 Elemente des Querschnitts 2.1.2 Elemente des Lageplans 2.1.3 Elemente des Höhenplans 2.1.4 Räumliche Linienführung 2.1.5 Sichtweite 2.1.6 Verfahren zur entwurfstechnischen Bewertung von Straßen 2.1.7 Schlussfolgerungen für die Untersuchung 2.2 Stand der Regelwerke 2.2.1 Gestaltungsgrundsätze der Entwurfsrichtlinien 2.2.2 Richtlinien für die Anlage von Landstraßen (RAL) 2.2.3 Merkblatt zur Übertragung des Prinzips der Entwurfsklassen auf bestehende Straßen (M EKLBest) 2.2.4 Erhaltungsplanung 2.2.5 Schlussfolgerungen für die Untersuchung 3 Ziel der Arbeit und Vorgehensweise 3.1 Ziel und Abgrenzung der Arbeit 3.2 Allgemeine Vorgehensweise 3.3 Möglichkeiten der Datenbereitstellung und Datenerhebung 3.3.1 Straßendatenbanken 3.3.2 Kinematische Datenerfassung und Datenaufbereitung 3.4 Netzweite Berechnung entwurfstechnischer Parameter 3.4.1 Abgrenzung der Straßenabschnitte 3.4.2 Berechnung der Fahrbahnbreite 3.4.3 Berechnung der Elementrelationen 3.4.4 Berechnung der Kurvigkeitsdifferenzen 3.4.5 Detektierung von kritischen Sichtschattenbereichen 3.4.6 Detektierung verdeckter Kurvenbeginne 3.5 Analyse des Unfallgeschehens 3.5.1 Kenngrößen der Unfallanalyse 3.5.2 Netzzuordnung der Unfälle 3.5.3 Spezifizierung der Unfalldaten 3.5.4 Berechnung der relativen Unfallkenngrößen 3.5.5 Bildung von Untersuchungskollektiven 3.5.6 Fahrbahnbreite 3.5.7 Kurvenradien und Elementfolgen 3.5.8 Kurvigkeit des Einzelbogens und Kurvigkeitsdifferenzen 3.5.9 Sichtschattenbereiche 3.5.10 Verdeckter Kurvenbeginn 4 Einfluss ausgewählter Entwurfsmerkmale auf die Verkehrssicherheit 4.1 Darstellung des Streckenkollektivs 4.2 Fahrbahnbreite 4.3 Kurvenradien und Elementfolgen 4.3.1 Kurvenradius 4.3.2 Folge gegensinnig gekrümmter Kurven 4.3.3 Folge gleichsinnig gekrümmter Kurven 4.3.4 Kurvenradien im Anschluss an Geraden 4.4 Kurvigkeit des Einzelbogens und Kurvigkeitsdifferenzen 4.4.1 Kurvigkeit des Einzelbogens 4.4.2 Kurvigkeitsdifferenzen 4.5 Kritische Sichtschattenbereiche 4.6 Verdeckter Kurvenbeginn 4.7 Zusammenfassung 5 Konzept zur Berücksichtigung entwurfs- und sicherheitstechnischer Aspekte bei PMS 5.1 Verfahren zur entwurfstechnischen Bewertung 5.1.1 Bewertungsphilosophie 5.1.2 Linienführung im Lageplan 5.1.3 Querschnittsgestaltung 5.1.4 Ableitung von Um-/Ausbauempfehlungen 5.2 Maßnahmen für Pavement-Management-Systeme (PMS) 5.2.1 Begriffe der Baulichen Erhaltung 5.2.2 Struktur und Aufbau von PMS 5.2.3 Wahl der Erhaltungsmaßnahmen in PMS 5.2.4 Ableitung zulässiger Erhaltungsmaßnahmen für PMS 5.2.5 Berücksichtigung von Um- und Ausbaumaßnahmen in PMS 5.2.6 Bewertung von Maßnahmen in PMS 5.3 Berücksichtigung von entwurfs- und sicherheitstechnischen Aspekten bei PMS - Verfahrensablauf 5.4 Abschätzung des Ausbaubedarfs von Straßennetzen - Verfahrensablauf 6 Zusammenfassung und Ausblick Literaturverzeichnis Abkürzungsverzeichnis Abbildungsverzeichnis Tabellenverzeichnis Anhangverzeichnis

Τα τελευταία χρόνια στις περισσότερες χώρες έχει ολοκληρωθεί η κατασκευή οδικών δικτύων και το ενδιαφέρον των φορέων οδοποιίας έχει στραφεί στη διαχείριση των υφιστάμενων οδικών κατασκευών. Το κυριότερο τμήμα της Διαχείρισης Οδικών Δικτύων καταλαμβάνει η Διαχείριση Οδοστρωμάτων. Τα Συστήματα Διαχείρισης Οδοστρωμάτων έχουν ως στόχο την οικονομική διαχείριση των οδοστρωμάτων και χρησιμοποιούν τεχνητή νοημοσύνη για να καταλήξουν στη βέλτιστη και οικονομικά αποδοτικότερη κατανομή των διαθέσιμων πόρων. Το ευφυές σύστημα που διαθέτουν καταφέρνει να εντοπίζει τη βέλτιστη λύση που ελαχιστοποιεί το κόστος συντήρησης αλλά δεν λαμβάνουν υπόψη τους το αντίκτυπο της επιδείνωσης της κατάστασης του οδοστρώματος στο χρήστη και στο περιβάλλον. Στην παρούσα εργασία χρησιμοποιείται ένας γενετικός αλγόριθμος και αναζητείται η βέλτιστη λύση που ελαχιστοποιεί το γενικευμένο κόστος, το οποίο περιλαμβάνει το κόστος συντήρησης, το κόστος του χρήστη εξαιτίας της κατάστασης του οδοστρώματος και το περιβαλλοντικό κόστος. Τα δεδομένα του προβλήματος αφορούν την κατάσταση των τμημάτων που πρόκειται να συντηρηθούν, το είδος της οδού στο οποίο ανήκουν τα τμήματα οδοστρώματος, τα στοιχεία φθορών κάθε τμήματος, τα διαθέσιμα είδη συντήρησης, το ύψος της χρηματοδότησης και τα κυκλοφοριακά χαρακτηριστικά της περιοχής στην οποία βρίσκονται τα υπό συντήρηση τμήματα. Ο αλγόριθμος κατασκευάζει γονίδια επιλέγοντας είδος συντήρησης για κάθε τμήμα και για κάθε χρόνο συμπεριλαμβανομένης και της επιλογής να μην γίνει καμία συντήρηση σε κάποιο χρόνο. Τα γονίδια ελέγχονται με βάση περιορισμούς που έχουν τεθεί από τα μοντέλα φθορών κάθε τμήματος και επιλέγονται να μεταφερθούν στην επόμενη γενιά αυτά που συνδυάζουν το ελάχιστο κόστος και το μέγιστο επίπεδο λειτουργικότητας στο οδόστρωμα. Η διαφορά του μοντέλου σε σχέση με τα κοινά συστήματα διαχείρισης οδοστρωμάτων έγκειται περισσότερο στις υπολογιστικές απαιτήσεις του συστήματος καθώς η εφαρμογή γενετικού αλγορίθμου οδηγεί γρηγορότερα σε λύση από ότι οι κλασικές μέθοδοι βελτιστοποίησης όπως π.χ. ο γραμμικός προγραμματισμός. Η καταλληλότητα και η ευκολία προσαρμογής των γενετικών αλγορίθμων σε προβλήματα διαχείρισης οδοστρωμάτων επαληθεύεται στην παρούσα εργασία. Το σύστημα καταφέρνει να εντοπίζει το βέλτιστο χρόνο με την οικονομικότερη συντήρηση του κάθε τμήματος του οδικού δικτύου και την πιο φιλική λύση για το χρήστη της οδού και το περιβάλλον.
In recent years the focus of the transportation authorities, researchers and practitioners is being shifted from the construction of new roads to the management of existing road structures and especially to road pavements. Pavement Management Systems are widely used and are continuously being improved because they can lead to considerable fund savings and/or to higher levels of service of road pavements. In this work, a model for pavement maintenance and rehabilitation planning and optimal resource allocation is presented. The objective function aims at minimizing a generalized cost parameter which includes a number of monetary cost components and no monetary impacts. In particular, the objective function consists of the following components: (1) agency cost (the cost of applying the selected maintenance and rehabilitation strategy), (2) user costs (they include vehicle operating cost for fuel consumption, vehicle maintenance and depreciation, traffic delay cost, accident cost, discomfort cost, and delay cost due to maintenance works and (3) environmental impact costs due to traffic pollution and noise. The above cost components are considered with regard to the existing pavement condition levels which are represented by the PSI index. Pavement condition deterioration is assessed through deterministic models that have been developed earlier by our team based on expert opinions and fuzzy systems considering pavement related and traffic parameters, i.e., pavement age, pavement strength, pavement construction quality and traffic loads. The maintenance and rehabilitation treatments are considered with regard to their cost and effectiveness characteristics. Besides the pavement condition deterioration functions, other constraints of the model include budgetary availability (total and individually for different highway groups), threshold values for the minimum accepted pavement condition levels (by highway class), desirable pavement condition levels (by highway class), maintenance and rehabilitation treatment applicability and effectiveness, etc. Due to the size and complexity of the problem (non linear functions), a genetic algorithm has been used as an optimization tool. The algorithm forms solutions by considering applicable maintenance treatments at each pavement section and year within the analysis period. Each solution is checked against all constraints to ensure the feasibility of the solution. No feasible solutions are discarded and new solutions are generated until the required offspring solutions are obtained. The optimization runs over several road sections with different traffic and pavement condition characteristics and within a time span of 10 years. The budgetary or the minimum accepted pavement condition constraints can be altered in order to get a Pareto-front set of optimal solutions for a particular application. Preliminary evaluation indicates that the model provides reasonable results in terms of the appropriate selection of maintenance and rehabilitation treatments and the time of application.