Dissertations / Theses on the topic 'Pavement roughne'

Pavement smoothness has become a standard measure of pavement quality. Transportation agencies strive to build and maintain smoother pavements. Smooth roads provide comfort while riding, minimize vehicular wear and tear and increase pavement life. A user perceives smoothness of a pavement based on the ride quality, which is severely affected by presence of defects on pavement surface. Defects identified after construction are corrected as per smoothness specifications prescribed by respective transportation agencies. The effectiveness of any method used to determine defect locations depends on the decrease in roughness obtained on correction of defects. Following the above line of thought a method that detects defects by comparing original profile to a smoothened profile will be more effective in identifying defect locations that cause roughness in pavements. This research report proposes a methodology to detect defect locations on pavement surface using profile data collected on pavements. The approach presents a method of obtaining a smoothened profile from the original profile to help identify defect locations based on deviations of the original profile from the smoothened one. Defect areas will have a higher deviation from the smoothened profile as compared to smooth areas. The verification of the defects identified by this approach is carried out by determining the decrease in roughness after removal of the identified defects from profile. A roughness statistic is used to do the same. The approach is illustrated using profile data collected on in-service pavement sections.

Several aspects of vehicle-pavement interaction have been studied and discussed in this thesis. Initially the pavement response is studied through a quasi-static and a dynamic computationally efficient framework under moving traffic loads. Subsequently, a non-stationary stochastic solution has been developed in order to account for the effect of pavement surface deterioration on pavement service life.The quasi-static procedure is based on a superposition principle and is computationally favourable, as it requires only a reduced incremental problem to be solved numerically. Using the developed framework, the effect of vehicle configuration and traffic characteristics on the damage induced in pavements is investigated numerically. It is shown that the developed numerical model provides a more accurate explanation of different distress modes.In the dynamic approach the pavement roughness and vehicle suspension system are linked to a dynamic pavement model in order to account for the dynamic effects of vehicle-pavement interaction on pavement response. A finite element method is employed in order to establish the response function for a linear viscoelastic pavement structure with dynamic effects taken into account. The developed computational procedure is applied to evaluate the effect of the pavement surface roughness on the pavement structure response to truck traffic loadings.Furthermore, the deterioration trends for the flexible pavement surface have been investigated based on field measurements of longitudinal profiles in Sweden. A predictive function is proposed for surface deterioration that is based on the average gradient of yearly measurements of the road surface profiles in Swedish road network. The developed dynamic framework is further elaborated to a non-stationary stochastic approach. The response of the flexible pavement is given for a non-stationary random case as the pavement surface deteriorates in pavement service life, thus influencing the magnitude of the dynamic loads induced by the vehicles. The effect of pavement surface evolution on the stress state induced in the pavement by moving traffic is examined numerically. Finally the effect of surface deterioration on pavement service life has been investigated and discussed in the thesis by incorporating the proposed prognostic surface deterioration model into a ME design framework. The results are discussed for different case studies with different traffic regimes. It was indicated that the predicted pavement service life decreases considerably when the extra dynamic loads, as a result of pavement surface deterioration, has been taken into account. Furthermore, the effect of performing a predictive rehabilitation process (i.e. resurfacing) has been studied by employing a LCC framework. The application of preventive maintenance was shown to be effective, especially when the deterioration rate is high.

QC 20141119

The research explores aspects of road surface measurement and monitoring, targeting some of the main challenges in the field, including cost and portability of high-speed inertial profilers. These challenges are due to the complexities of modern profilers to integrate various sensors while using advanced algorithms and processes to analyse measured sensor data. Novel techniques were proposed to improve the accuracy of road surface longitudinal profiles using inertial profilers. The thesis presents a Half-Wavelength Peak Matching (HWPM) model, designed for inertial profilers that integrate a laser displacement sensor and an accelerometer to evaluate surface irregularities. The model provides an alternative approach to drift correction in accelerometers, which is a major challenge when evaluating displacement from acceleration. The theory relies on using data from the laser displacement sensor to estimate a correction offset for the derived displacement. The study also proposes an alternative technique to evaluating vibration velocity, which improves on computational factors when compared to commonly used methods. The aim is to explore a different dimension to road roughness evaluation, by investigating the effect of surface irregularities on vehicle vibration. The measured samples show that the drift in the displacement calculated from the accelerometer increased as the vehicle speed at which the road measurement was taken increased. As such, the significance of the HWPM model is more apparent at higher vehicle speeds, where the results obtained show noticeable improvements to current techniques. All results and analysis carried out to validate the model are based on real-time data obtained from an inertial profiler that was designed and developed for the research. The profiler, which is designed for portability, scalability and accuracy, provides a Power Over Ethernet (POE) enabled solution to cope with the demand for high data transmission rates.

The research explores aspects of road surface measurement and monitoring, targeting some of the main challenges in the field, including cost and portability of high-speed inertial profilers. These challenges are due to the complexities of modern profilers to integrate various sensors while using advanced algorithms and processes to analyse measured sensor data. Novel techniques were proposed to improve the accuracy of road surface longitudinal profiles using inertial profilers. The thesis presents a Half-Wavelength Peak Matching (HWPM) model, designed for inertial profilers that integrate a laser displacement sensor and an accelerometer to evaluate surface irregularities. The model provides an alternative approach to drift correction in accelerometers, which is a major challenge when evaluating displacement from acceleration. The theory relies on using data from the laser displacement sensor to estimate a correction offset for the derived displacement. The study also proposes an alternative technique to evaluating vibration velocity, which improves on computational factors when compared to commonly used methods. The aim is to explore a different dimension to road roughness evaluation, by investigating the effect of surface irregularities on vehicle vibration. The measured samples show that the drift in the displacement calculated from the accelerometer increased as the vehicle speed at which the road measurement was taken increased. As such, the significance of the HWPM model is more apparent at higher vehicle speeds, where the results obtained show noticeable improvements to current techniques. All results and analysis carried out to validate the model are based on real-time data obtained from an inertial profiler that was designed and developed for the research. The profiler, which is designed for portability, scalability and accuracy, provides a Power Over Ethernet (POE) enabled solution to cope with the demand for high data transmission rates.

Irregularities in pavement profiles that exceed standard thresholds are usually rectified using a Diamond Grinding Process. Diamond Grinding is a method of Concrete Pavement Rehabilitation that involves the use of grinding wheels mounted on a machine that scraps off the top surface of the pavement to smooth irregularities. Profile Analysis Software like ProVAL© offers simulation modules that allow users to investigate various grinding strategies and prepare a corrective action plan for the pavement. The major drawback with the current Smoothness Assurance Module© (SAM) in ProVAL© is that it provides numerous grind locations which are both redundant and not feasible in the field. This problem can be overcome by providing a constrained grinding model in which a cost function is minimized; the resulting grinding strategy satisfies requirements at the least possible cost. Another drawback with SAM exists in the built-in grinder models that do not factor in the effect of speed and depth of cut on the grinding head. High speeds or deep cuts will result in the grinding head riding out the cut and likely worsening the roughness. A constrained grinding strategy algorithm with grinder models that factor in speed and depth of cut that results in cost effective grinding with better prediction of post grind surfaces through simulation is developed in this work. The outcome of the developed algorithm is compared to ProVAL's© SAM results.
Master of Science

The road system under the care and control of the State of Queensland, Australia has an estimated replacement value of $23 Billion (US$12 billion), excluding structures. Pavement management systems for recording, rating, and predicting a pavement's condition are used to prudently manage this large asset. Tne of the fundamental components of a pavement management system is the method of determining a pavement's rate of deterioration over time. Throughout the world, "pavement roughness" is one of the most widely used methods of measuring the performance of a pavement. Queensland is a large State, having an approximate area of 1.7 million square kilometres, and incorporates many small communities separated by vast distances. The majority of bitumen sealed pavements exist in low traffic volume rural areas, and consist of either a flexible unbound granular pavement or a semi-rigid modified granular pavement. This study has focussed on the roughness progression of these pavement types. Roughness data has been collected at varying frequencies since 1987, across the State's road network. In order to understand roughness progression behaviour, this research has considered 16,000 pavement segments (each lkm) from all parts of the State. This number is significant, as many previous research efforts, which form the basis of the current roughness progression models, have been based on the study of typically between forty and several hundred pavement segments. This extensive database has been used in this study to investigate trends in roughness pogression over time (~R). Traditionally, roughness progression has been represented in many road asset management models as an exponential relationship, providing rapidly increasing roughness values as the pavement approaches the end of its theoretical life. However, this relationship has not been commonly observed in the State's pavement asset. Investigations revealed that a linear relationship, termed the Linear Roughness Progression Rate (LRPR), represented the roughness progression of the pavement segments very well, and thereby assists in the identification of poor performing pavement segments. Pavement maintenance costs can also be used to identify poor performing pavement segments, based on excessive use of pavement maintenance funds to maintain functionality. This information assists in 'unmasking' pavements that may possess an umepresentative LRPR. For this reason, the effects of pavement maintenance costs (~PMC) on roughness progression have also been examined. Independent variables which are typically considered to affect roughness progression, have been examined with LRPR in this study. These variables include traffic volume, traffic loading, pavement type, subgrade soil classification, climate (rainfall, temperature, Thomthwaite Index), pavement age, and width of bitumen surface (seal width). It has been established that the roughness progression of each individual pavement segment is unique. No particular formula or model has been identified, which can accurately predict the roughness progression of any particular pavement segment from a population, based upon known values of the independent variables. In order to develop an understanding of the effects of these variables on pavement performance, a means of rating a pavement's condition using a combination of LRPR and excessive pavement maintenance expenditure has been established. Subsequently, a discrete rating scale from "Good", "Fair" to "Poor" has been used. The effects of the independent variables on pavement rating have been examined across the population of study pavement segments, using summary charts. This has enabled the proportions of pavement rated within each category to be examined with changes in each independent variable, to establish whether that variable has a global influence on pavement rating. For instance, whether the proportion of pavements rated "Poor" varies with Annual Average Daily Traffic. These summary charts provide the basis of a Network Performance Profile, which has yielded a better understanding of the variables globally influencing pavement rating across the State's road network. Further, the Network Performance Profile provides insight into the inbuilt risk of the past and current pavement design and delivery system. The knowledge gained from a whole of network analysis of condition may form a catalyst for the assessment of material quality, design methods, construction technology, and contract delivery, to ensure that pavements have the best chance of performing well. Currently, road network performance is commonly defined only by a measure of the road network's 'Absolute Condition'. The Network Performance Profile developed in this study will add new measures of pavement performance to the current definition. By including a Current Network Profile, and a more robust method for predicting mid term (five year) roughness values, asset managers will have a suite of information on historic, current, and estimated future road network condition, to use in evaluating the impact of previous and current management decisions. Pavement roughness prediction analysis, based on site-specific extrapolation of LRPR, has shown that at least six time-series roughness data points are required if an accurate short term prediction (4 to 6 year) is to be achieved. It is believed that the research of roughness progression has highlighted the unique nature of pavement segment deterioration. It is interesting to note that all categories of pavements suffer from a range of good to poor performance, and this finding is considered to be one of the keys in understanding pavement behaviour. At a network level, the study of performance has been considered very successful and has not only provided a robust methodology for quantifying road network performance, but also provides information for input into the improvement of technical policies and funding distribution decisions.

The objectives of this research were to 1) investigate the effects of lower concrete albedo on the thermal behavior of concrete pavement by directly comparing temperatures and moisture contents of typical and darkened concrete pavements and 2) investigate changes in roughness of both typical and darkened concrete pavements as a result of changes in temperature and moisture gradients. The scope of the research included instrumentation, testing, and analysis of typical and darkened concrete pavements constructed in northern Utah.Procedures related to field testing included infrared thermography, thermocouple readings, sensor data collection, and roughness surveys. Elevation surveys and albedo measurements were also performed to further characterize the site. Procedures related to laboratory testing included elastic modulus, compressive strength, rapid chloride permeability, thermal conductivity, and Schmidt rebound hammer testing of cylinders prepared from typical and darkened concrete.When considered over the entire monitoring period, the average surface temperatures of the darkened pavement were higher than those of the typical pavement by 3.3°F, and the average subsurface temperatures of the darkened pavement were higher than those of the typical pavement by 3.1°F. A strong positive correlation exists between the air temperature and both the surface and the subsurface pavement temperatures. The difference between both the surface and subsurface temperatures of the darkened and typical pavements decreases as the air temperature decreases. The results of a simple linear regression suggest that, when the air temperature is 32°F, the surface temperature of the darkened concrete is just 0.2°F higher than that of the typical concrete and the subsurface temperature of the darkened concrete is 1.1°F higher than that of the typical concrete. The difference in surface temperature is expected to be 0°F when the air temperature is 30.5°F, while the difference in subsurface temperature is expected to be 0°F when the air temperature is 17.9°F. Therefore, the darkened pavement is unlikely to melt snow and ice faster than the typical pavement or provide significantly greater frost protection to subsurface layers and buried utilities during winter for conditions similar to those in this research. The roughness measurements for the typical pavement exhibit much more daily variability than seasonal variability. The roughness measurements for the darkened pavement also exhibit more daily variability than seasonal variability but less overall variability than that of the typical pavement. Neither pavement temperature gradient nor moisture gradient appears to be correlated to roughness for either the typical pavement or the darkened pavement.

While cement treatment is a proven method for improving the strength and durability of soils and aggregates, cement hydration causes shrinkage strains in the cement-treated base (CTB) that can lead to reflection cracking in asphalt surfaces. Cracking may then cause increased pavement roughness and lead to poor ride quality. The overall purpose of this research was to utilize data collected through the Long-Term Pavement Performance (LTPP) program to investigate the use and classification of CTB layers and evaluate the relative impact of cement content on the development of roughness and cracking in asphalt concrete (AC) pavements constructed using CTB layers. The data included 52 LTPP test sites, which represented 13 different states and one Canadian province, with cement contents ranging from 3.0 to 9.5 percent by weight of dry aggregate. Statistical procedures were utilized to identify the factors that were most correlated to the observed pavement performance and to develop prediction equations that transportation agencies can use to estimate the amount of roughness for a given pavement at a given age and the amount of distress associated with a particular crack severity level for a given pavement. The data collected for this study suggest that wide ranges of cement contents are used to stabilize soils within individual American Association of State Highway and Transportation Officials soil classifications. The data also suggest that CTBs comprising flexible pavement structures are constructed mainly on rural facilities. A backward-selection model development technique was used to develop sets of prediction equations for roughness and cracking. Age, AC thickness, CTB thickness, and cement content were determined to be significant predictors of International Roughness Index, while age, air freezing index, AC thickness, CTB thickness, cement content, and traffic loads in thousands of equivalent single-axle loads were determined to be significant predictors of low-severity, medium-severity, and high-severity block, fatigue, longitudinal (wheel-path and non-wheel-path), and transverse cracking in AC pavements constructed using CTB layers. Investigation of the relationships between CTB modulus and the development of roughness and cracking is recommended for further study.

Pavement roughness has been found to have an effect on the coefficient of friction measured with the Locked-Wheel Skid Tester (LWT) with measured friction decreasing as the long wave roughness of the pavement increases. However, the current pavement friction standardization model adopted by the American Society for Testing and Materials (ASTM), to compute the International Friction Index (IFI), does not account for this effect. In other words, it had been previously assumed that the IFI's speed constant (SP), which defines the gradient of the pavement friction versus speed relationship, is an invariant for any pavement with a given mean profile depth (MPD), regardless of its roughness. This study was conducted to quantify the effect of pavement roughness on the IFI's speed constant. The first phase of this study consisted of theoretical modeling of the LWT using a two-degree of freedom vibration system. The model parameters were calibrated to match the measured natural frequencies of the LWT. The calibrated model was able to predict the normal load variation during actual LWT tests to a reasonable accuracy. Furthermore, by assuming a previously developed skid number (SN) versus normal load relationship, even the friction profile of the LWT during an actual test was predicted reasonably accurately. Because the skid number (SN) versus normal load relationship had been developed previously using rigorous protocol, a new method that is more practical and convenient was prescribed in this work. This study concluded that higher pavement long-wave roughness decreases the value of the SP compared to a pavement with identical MPD but lower roughness. Finally, the magnitude of the loss of friction was found to be governed by the non-linear skid number versus normal load characteristics of a pavement.

Este trabalho teve como objetivo pesquisar a tipologia e as possíveis causas da ocorrência das patologias em pavimentos de concreto armado, bem como verificar a aplicabilidade e analisar criticamente os métodos de avaliação do estado funcional destes pavimentos. São apresentados os tipos e os graus de severidade das patologias descritas no método do United States Corps of Engineers (USACE), bem como os métodos de avaliação da superfície dos pavimentos de concreto, dentre eles, o índice internacional de irregularidade (International Roughness Index - IRI), o quociente de irregularidade (QI), o valor da serventia atual (VSA) e a avaliação subjetiva e objetiva do índice de condição do pavimento (ICP). A aplicação prática se concentrou nos estudos de caso de quatro pavimentos de concreto armado, sendo um pavimento urbano e três pavimentos industriais, realizando a avaliação detalhada das patologias existentes nos pavimentos em serviço, com posterior cálculo do valor do ICP. Foi avaliada também a irregularidade longitudinal (IRI), com um perfilômetro inercial, no estudo de caso do pavimento urbano, com o intuito de verificar se este método apresenta correlação com o critério do ICP para o caso dos pavimentos de concreto armado como indicador de desempenho. Os levantamentos permitiram verificar valores intermediários de ICP para os pavimentos analisados e que tal situação é decorrente principalmente de falhas construtivas. Os defeitos catalogados no manual do ICP são suficientes para descrição das patologias encontradas durante os levantamentos. Com o auxílio de uma maior quantidade de levantamentos seria possível estabelecer relações entre ICP e IRI sendo que a relação encontrada com base no universo estudado foi fraca, embora aponte uma tendência. O trabalho enfatiza o estudo e a aplicabilidade do método de avaliação objetiva do USACE que é amplamente empregado nos E.U.A. Por fim discute possível relação entre os valores do ICP e do IRI no caso estudado.
This research aimed to verify types and possible causes for the occurrence of distresses in reinforced concrete pavements as well as to verify the applicability and critically examine the methods for assessment of the functional condition for such pavements. It is presented the distresses types and its severity levels described by the method of the United States Corps of Engineers (USACE), as well as the methods for surface evaluation of concrete pavements, including the international roughness index (IRI), the quarter of car index (QI), the present serviceability ratio (PSR) and subjective and objective evaluation of the pavement condition index (PCI). The practice study focused in four cases of reinforced concrete pavements, an urban pavement and three industrials floors, consisting on detailed field evaluation of distresses with subsequent determination of PCI for several pavement sections. It was carried out a field measurement of IRI using an inertial profiler for the case of urban pavement, in order to verify whether this method could reflect the actual the performance of reinforced pavement concrete. The performed surveys allowed understanding that most of cases with low PCI values are due to constructive fails. The list of distresses suggested by PCI manual is suffice to identify the distresses found out during the surveys. However it shall be required a large amount of field surveys in order to define better correlation between PCI and IRI in view of the current results.

The subject of the master thesis is to verify the possibility of application of geodetic methods to determine longitudinal and transverse pavement surface roughnesses. Geodetic techniques are compared to techniques specified in ČSN 73 6175. Subject of testing is absolute and relative accuracy of altitude measurement and accuracy of roughness parameter determination. As a result, the graphic interpretation of these parameters and deviations from reference values are presented in the current document. Practical use of the surveying methods is evaluated based on the application of the above mentioned techniques and the results of accuracy analysis.

Previous studies show that pavement condition properties are significant factors to enhance road safety and riding experience, and pavements with low quality might have inadequate performance in terms of safety and riding experience. Pavement Management System (PMS) databases include pavement properties for each segment of the road collected by the agencies. Understanding the impact of road characteristics on crash frequency is a key step to prevent crashes. Whereas other studies analyzed the effect of different characteristics such as International Roughness Index (IRI), Rutting Depth (RD), Annual Average Daily Traffic (AADT), this thesis analyzed the effect of Critical Condition Index (CCI) on crash frequency, in addition to the other factors identified in previous studies. Other characteristics such as Percentage of Heavy Vehicles, Road Surface Condition, Road Lighting Condition, and Driver Conditions are taken into the consideration. The scope of the study is the interstate highway system in Fairfax County, Virginia. Negative Binomial, Least Square and Nominal Logistic Models were developed, showing that the CCI value is a significant factor to predict the number of crashes, and that it has different effect for different values of AADT. The result of this study is a substantial step towards developing an integrated transportation control and infrastructure management framework.
Master of Science
Many factors cause crashes in the roads. Although there is a common sense that road characteristics such as asphalt quality are important in terms of road safety, there are few studies that scientifically prove that statement. In addition, asphalt maintenance decisions making process is mainly based on cost benefit optimization, and traffic safety is not considered at the process. The purpose of this study is to analyze crashes and road characteristics related to each crash to understand the effect of those characteristics on crash frequency, and eventually, to build a model to predict the number of crashes at each part of the road. The model can help transportation agencies to have a better understanding in terms of safety consequences of their infrastructure management plans. The scope of this study is the highway interstate system in Northern Virginia. Results suggest that pavement condition has a significant impact on crash frequency.

The objective of this research was to analyze the strength and deformation characteristics of a cement-treated base (CTB) constructed using full-depth reclamation, microcracked, and then surfaced with a single chip seal. In this field study, strength characteristics of the CTB layer were determined at the time of construction, and then both strength and deformation characteristics were evaluated after 9 months of low-volume, heavy truck traffic. After 9 months, observed distresses included transverse cracking, rutting, and chip seal joint failure. The loss of the chip seal was caused by poor chip seal construction practices and not a deficiency in the CTB layer. The importance of the role of the chip seal as a wearing course was made evident by these failures since the exposed CTB often exhibited material loss. The average ride qualities in and out of the wheel path were in the fair ride category; the roughness was not likely caused by trafficking but probably resulted from construction or climatic factors. Structural testing performed after 9 months of service indicated that the CTB stiffness and modulus were greater than the values measured after microcracking at the time of construction, indicating continued strength gain. However, trafficking over the 9-month period had caused significantly lower stiffnesses measured in the wheel paths than between the wheel paths. The average unconfined compressive strength (UCS) of the cores tested at 9 months was not significantly different than the average UCS of the field-compacted specimens tested at 6 weeks. Based on the observed performance of the CTB and chip seal evaluated in this research, recommendations for improved CTB performance include the use of a thicker and/or stiffer CTB layer, ensuring a smooth CTB surface during construction, and application of a double chip seal or equivalent.

This thesis developed a new methodological framework for studying how road conditions contribute to motorcycle crash risk. Using specific engineering approaches, the data collected by an instrumented motorcycle were transformed into measures of road geometry and road surface quality. Their contributions to crash risk were then examined using an epidemiological case-crossover design. The method was tested using crash and road data from the Gillies Range Road in Northern Queensland.

Research was performed to analyze the performance of the crack, seat, and overlay (CS&O) roadway rehabilitation technique in the Central Coast and Northern regions of California. This technique was evaluated through literature review to determine the state of practice and their conclusions. California highway sections rehabilitated using CS&O were selected for evaluation based on age and location. Pavement distresses and traffic data for these sections were collected and analyzed. Prior to beginning analysis this data was checked for errors, outliers, and omissions. The analysis consisted of checking the data for correlations among distresses and regions. The focus of this research is to develop performance prediction models for pavement distresses in CS&O sections. Using data collected from Caltrans’ Pavement Condition Reporting Software, performance models were developed based on dependent (distress) variables: alligator cracking, transverse cracking, longitudinal cracking, and International Roughness Index (IRI). And independent (explanatory) variables: age, traffic in the form of equivalent single axle load (ESAL), thickness of hot mix asphalt (HMA), thickness of Portland Cement Concrete (PCC), and cumulative traffic in the form of cumulative ESAL. Prediction models were then analyzed for preciseness and sensitivity to the variables included in each model.

Availability of analytical and numerical tools that can provide reliable and accurate estimates of wet frictional resistance in different pavements would preclude the need for time consuming field tests. Therefore, many research efforts have been made to develop such tire-pavement friction predictive tools that are invaluable for friction management programs. However, due to the complexity of the problem, most existing tools have been developed based on several simplifying assumptions and without field verification of their predictions. The current study is focused on the evaluation of two specific prediction methods that can be used to predict friction on a smooth tire sliding on a rough moist pavement by comparing the corresponding predictions with the results of field experiments. A 3-dimensional finite element model (FEM) formulated in ANSYS software and an analytical method based on computing hysteresis friction from viscous energy dissipation are the two methods considered in this study. Both prediction tools are capable of considering rough pavement surface texture while the FEM method can even incorporate the specific tire geometric and material properties. Friction predictions of the two methods based on the macrotexture data collected at a selected test surface provide reasonably accurate results when compared to the corresponding field evaluation. The main finding of the investigation is the availability of relatively easily executed analytical methodologies that are comparable in accuracy to more rigorous finite element tools. The second stage of the research was focused on wet weather friction of a tire sliding on a randomly rough pavement. A numerical model was developed to predict the drag force of a sliding tire on a wet rough pavement. The model consists of three sub-models; the fluid model based on the Reynolds equation, tire model developed with two sets of springs and a rigid pavement model. As a contribution to the state-of-the-art the author modeled the pavement by including randomly rough properties which represent real pavements. The results of the parametric study based on the model predictions are agreeable with physical principles and intuition. However, this model is only capable of simulating laminar water flow between the tire and the pavement whereas in reality turbulent flow can occur very often on a randomly rough pavement.

The issue of this diploma thesis is measurement of pavement roughness with an alternative means of data acquisition and evaluation by geodetic methods. In the beginning there is an overview of current state of actual roughness measurement methods. The main work is concerned with data acquisition with passive reflection of the laser rangefinder and laser scanner and standard deviations that arise in measuring on asphalt and concrete road surfaces. The aim of the work is to formulate the process of data acquisition, specification of standard deviations in the process of measuring, evaluation of pavement roughness according to ČSN 73 6175 standard, and their applicable graphic interpretation. Based on the analysis of accuracy of the methods applied, their usefulness is evaluated in comparison with the straightedge test.

Disertacijos tikslas – parengti magistralinių automobilių kelių asfaltbetoninės dangos eksploatacinių rodiklių prognozės matematinius modelius, atsižvelgiant į tampriosios dangos konstrukcijos savybes ir transporto priemonių (TP) eismo intensyvumą (EI). Darbe iškelti šie svarbiausieji uždaviniai: išanalizuoti automobilių kelių asfaltbetoninės (AB) dangos eksploatacinius rodiklius lemiančius svarbiausius veiksnius ir atskleisti šių rodiklių blogėjimo priežastis; atlikti magistralinių kelių dangos konstrukcijų (KDK) sluoksniams naudojamų medžiagų kokybės rodiklių tyrimus; nustatyti AB dangos komponentinės sudėties, fizinių bei mechaninių rodiklių ir AB mišiniams naudojamų medžiagų kokybės rodiklių sietį; ištirti AB dangos lygumo ir provėžų gylio kitėjimo dėsningumus; nustatyti AB dangos, kitų (KDK) sluoksnių medžiagų kokybės rodiklių sietį; parinkti dvi racionalias magistralinių kelių tampriosios dangos konstrukcijas (skirtingam TP eismui). Disertaciją sudaro įvadas, keturi skyriai, rezultatų apibendrinimas, naudotos literatūros ir autoriaus publikacijų disertacijos tema sąrašai ir priedai. Įvade aptarta tiriamoji problema, darbo aktualumas, tyrimų objektas, darbo tikslas ir uždaviniai, tyrimų metodika, darbo mokslinis naujumas, darbo rezultatų praktinė vertė ir ginamieji teiginiai. Pirmajame skyriuje išnagrinėti įvairių šalių mokslininkų atlikti automobilių kelių asfaltinės dangos bei jos konstrukcijos eksploatacinių rodiklių ir jų funkcionavimo trukmės tyrimai. Antrajame... [toliau žr. visą tekstą]
The aim of the dissertation is based on the properties of flexible road pavement structures to develop a mathematical models for predicting the performance of wearing courses used in the pavements of the main roads. The main tasks of the dissertation are as follows: to analyze the main factors influencing the service indices of asphalt concrete pavements and to determine their reasons; to investigate the quality of materials and mixtures used in pavement structural layers of the main roads; to determine the interaction between asphalt concrete pavement composition and the quality indices of mixture materials; to study regularities of the change in pavement roughness and rut depth; to determine the interaction between the quality indices of materials used in pavement structural layers; to select two rational flexible pavement structures for the main roads (for the different traffic volume). The dissertation consists of introduction, four chapters, general conclusions, the list of references and the list of author’s publications on the topic of the dissertation, addenda. Introduction describes the studied problem, topicality of the problem, the object of research, also the aim and tasks, research methodology, scientific novelty, practical value of the results and the defended propositions. Chapter 1 gives the analysis of scientific researches made by different countries in the field of the performance of asphalt concrete pavements and their structures, duration of their... [to full text]

The aim of the dissertation is based on the properties of flexible road pavement structures to develop a mathematical models for predicting the performance of wearing courses used in the pavements of the main roads. The main tasks of the dissertation are as follows: to analyze the main factors influencing the service indices of asphalt concrete pavements and to determine their reasons; to investigate the quality of materials and mixtures used in pavement structural layers of the main roads; to determine the interaction between asphalt concrete pavement composition and the quality indices of mixture materials; to study regularities of the change in pavement roughness and rut depth; to determine the interaction between the quality indices of materials used in pavement structural layers; to select two rational flexible pavement structures for the main roads (for the different traffic volume). The dissertation consists of introduction, four chapters, general conclusions, the list of references and the list of author’s publications on the topic of the dissertation, addenda. Introduction describes the studied problem, topicality of the problem, the object of research, also the aim and tasks, research methodology, scientific novelty, practical value of the results and the defended propositions. Chapter 1 gives the analysis of scientific researches made by different countries in the field of the performance of asphalt concrete pavements and their structures, duration of their... [to full text]
Disertacijos tikslas – parengti magistralinių automobilių kelių asfaltbetoninės dangos eksploatacinių rodiklių prognozės matematinius modelius, atsižvelgiant į tampriosios dangos konstrukcijos savybes ir transporto priemonių (TP) eismo intensyvumą (EI). Darbe iškelti šie svarbiausieji uždaviniai: išanalizuoti automobilių kelių asfaltbetoninės (AB) dangos eksploatacinius rodiklius lemiančius svarbiausius veiksnius ir atskleisti šių rodiklių blogėjimo priežastis; atlikti magistralinių kelių dangos konstrukcijų (KDK) sluoksniams naudojamų medžiagų kokybės rodiklių tyrimus; nustatyti AB dangos komponentinės sudėties, fizinių bei mechaninių rodiklių ir AB mišiniams naudojamų medžiagų kokybės rodiklių sietį; ištirti AB dangos lygumo ir provėžų gylio kitėjimo dėsningumus; nustatyti AB dangos, kitų (KDK) sluoksnių medžiagų kokybės rodiklių sietį; parinkti dvi racionalias magistralinių kelių tampriosios dangos konstrukcijas (skirtingam TP eismui). Disertaciją sudaro įvadas, keturi skyriai, rezultatų apibendrinimas, naudotos literatūros ir autoriaus publikacijų disertacijos tema sąrašai ir priedai. Įvade aptarta tiriamoji problema, darbo aktualumas, tyrimų objektas, darbo tikslas ir uždaviniai, tyrimų metodika, darbo mokslinis naujumas, darbo rezultatų praktinė vertė ir ginamieji teiginiai. Pirmajame skyriuje išnagrinėti įvairių šalių mokslininkų atlikti automobilių kelių asfaltinės dangos bei jos konstrukcijos eksploatacinių rodiklių ir jų funkcionavimo trukmės tyrimai. Antrajame... [toliau žr. visą tekstą]

Devido à grande predominÃncia do modal de transporte rodoviÃrio no Brasil, se faz cada vez mais necessÃrio um controle sobre as aÃÃes de manutenÃÃo e de conservaÃÃo das rodovias. Para isso, muitos ÃrgÃos rodoviÃrios adotam modernos sistemas informatizados, que à o caso do DER/CE, que utiliza o SIGMA (Sistema Integrado de GestÃo da ManutenÃÃo). O sistema, atravÃs do subsistema SGP (Sistema de GerÃncia de Pavimentos), possui um vasto banco de dados relativos à condiÃÃo das rodovias, que à alimentado com dados provenientes de levantamentos de campo, que trazem, periodicamente, informaÃÃes atualizadas da condiÃÃo das rodovias estaduais. Estes dados sÃo adquiridos utilizando metodologias definidas pela equipe tÃcnica do DER/CE, baseadas em procedimentos normalizados, sendo os principais: o levantamento de irregularidade longitudinal (IRI) e o Levantamento Visual ContÃnuo (LVC). O primeiro avalia o conforto ao rolamento e o segundo registra os defeitos de superfÃcie das rodovias. Esta pesquisa apresenta uma anÃlise comparativa entre dados de LVC e de IRI, avaliando a evoluÃÃo das quantidades de defeitos e do IRI e as metodologias e os equipamentos envolvidos nos levantamentos. Apresenta, ainda, uma tentativa de compreensÃo da evoluÃÃo dos parÃmetros medidos pelo LVC ao longo de oito anos. Espera-se que, com a contribuiÃÃo desta pesquisa, as metodologias e os dados relativos à condiÃÃo das rodovias sejam analisados considerando as limitaÃÃes encontradas e que sejam sempre adotados o equipamento e o procedimento mais apropriados.
Due to the large predominance of the transportation by highways in Brazil, it is necessary to control the actions related to maintenance and conservation of the roads. With this purpose, institutions make use of modern computational systems, such as the DER/CE, which uses the ISMA (Integrated System of Maintenance Administration). The referred system, using the subsystem PMS (Pavement Management System), has a large database related to the roads condition, filled with data provided by surveys that bring periodically up to date information of the state roads. These data are acquired by using methodologies defined by the technical staff of the DER/CE, based on the following normalized procedures: Visual Continuous Survey (LVC) and International Roughness Index Survey (IRI). The first one evaluates the comfort of the traffic rolling and the second registers the surface distresses of the roads. This research presents a comparative analysis between LVC and IRI data, evaluating the evolution of the distresses and the methodologies and equipments involved in the procedures. It is expected that, with the contribution of this research, the methodologies and road related data be analyzed considering the limitations of the equipments and procedures.

O desenvolvimento de novas técnicas de dimensionamento, construção e gerência de pavimentos requer o conhecimento dos efeitos dinâmicos da interação veículo-via, que dependem da irregularidade longitudinal do pavimento e de fatores associados ao veículo, como o espaçamento entre eixos, a velocidade de operação, caraterísticas de suspensão, a pressão de enchimento dos pneus e o tipo de rodagem dos eixos traseiros (rodagem dupla ou simples). Esta pesquisa tem por objetivo principal a quantificação das solicitações dinâmicas de veículos rodoviários de carga sobre os pavimentos, mediante utilização do programa computacional TruckSim e visa a quantificação dos efeitos dos fatores carga por eixo, tipo de veículo, velocidade dos veículos e irregularidade longitudinal sobre o desempenho dos pavimentos. Os resultados mostram que os efeitos dinâmicos, particularmente quando os pavimentos estão em condição ruim (IRI superior a 4), têm potencial de intensificar as forças atuantes na via em até 280%, considerando-se um excesso de carga de 7,5%, que é a tolerância estabelecida pela legislação brasileira, e que, de uma maneira global, podem reduzir a vida em serviço de um pavimento em até 87%.
The development of new techniques for design, construction and management of pavements requires the knowledge of the dynamic effects associated to vehicle-track interactions, which depends on the pavement roughness and vehicle characteristics, such as the spacing between axles, the operational speed, characteristics of suspension, the tire inflation pressure and wheel type of rear axle (dual or single). The main goal of this research is quantifying the dynamic stresses of road freight vehicles on the pavements, by using the computer program TruckSim, and aims to quantify the effects of the factors: axle load, vehicle type, vehicle speed and longitudinal roughness on the pavement performance. The results show that the dynamic effects, particularly when the pavements are in poor condition (IRI greater than 4), have the potential to intensify the forces acting on the road up to 280%, considering an overload of 7.5%, which is the tolerance established by Brazilian law, and that in global effects it can reduce the service-life of a pavement up to 87%.

A presente pesquisa engloba a análise de diversos aspectos a respeito da avaliação de irregularidade longitudinal de pavimentos, tratando mais detidamente das situações em que tal avaliação é executada a partir de perfis longitudinais medidos com perfilômetros inerciais, tipo de equipamento que também é objeto de exame. A análise é iniciada com o entendimento da evolução histórica deste tipo de avaliação funcional que abrange não só os equipamentos, como também os métodos de avaliação e os índices de irregularidade utilizados no Brasil. O trabalho relata as principais etapas do desenvolvimento do perfilômetro inercial que foi usado nesta pesquisa, seus aspectos técnicos e operacionais, além dos resultados dos testes que evidenciaram seu funcionamento e também uma comparação com os resultados obtidos por um medidor de irregularidade do tipo resposta. A pesquisa é completada com uma série de análises a respeito do método mais adequado para a verificação do funcionamento de perfilômetros inerciais, abarcando importantes recomendações para a escolha e medição de perfis de referência indispensáveis em tais verificações. São discutidos importantes aspectos do processamento de perfis para a determinação do QI que concluíram pela indicação da redução do espaçamento entre pontos do perfil para 25 cm. As incertezas dos índices QI e IRI obtidos a partir de perfilômetros inerciais são também abordadas, sendo que se constatou que o índice QI é afetado por grandes comprimentos de onda que normalmente não são considerados como irregularidade. A correlação entre os índices QI e IRI é amplamente avaliada através de dados reais de perfis de centenas de quilômetros de rodovias, que evidenciaram a existência de grande dispersão em tal correlação indicando que o melhor é não correlacioná-los. Por fim, a pesquisa deixa como legado a proposta de um anteprojeto de norma brasileira para este tipo de avaliação que abarca os julgamentos de todo o trabalho.
This research includes de analysis of several aspects regarding longitudinal pavement roughness evaluation, more specifically when these evaluations are done using an inertial profiler - kind o equipment that is also an object of this study. The analysis is initiated with the comprehension of the historical evolution of this type of functional evaluation that not only encloses equipment, but also the methods and the roughness indexes more common in Brazil. The main stages throughout of the development of the inertial profiler used on this research, its technical and operational features, the results of the tests that proved its good functionality and also the comparison of the results obtained with a response type roughness meter were incorporated. The research is completed with a series of analysis regarding the methods more appropriate for the verification of inertial profilers functioning, including important recommendations for the choice and measurement of reference profiles, indispensable in such verifications. Important aspects concerning profiles processing for the QI determination were verified and concluded for reduction of the displacement between the profile elevations for 25 cm. The uncertainties of QI and IRI indexes obtained from inertial profiles measurements were also researched and at this opportunity it was verified that value of QI is affected by long wavelengths that usually are not considered roughness. The correlation between QI and IRI indexes were widely evaluated using real data of hundreds of kilometers of highways profiles, and evidenced the existence of a great dispersion in such correlation what indicates that the best recommendation is not to correlate them. Finally, this research leaves as a legacy the proposal of a first draft for a Brazilian standard for this type of roughness evaluation that accumulates most of the judgments presented here.

Transport regulators consider that, with respect to pavement damage, heavy vehicles (HVs) are the riskiest vehicles on the road network. That HV suspension design contributes to road and bridge damage has been recognised for some decades. This thesis deals with some aspects of HV suspension characteristics, particularly (but not exclusively) air suspensions. This is in the areas of developing low-cost in-service heavy vehicle (HV) suspension testing, the effects of larger-than-industry-standard longitudinal air lines and the characteristics of on-board mass (OBM) systems for HVs. All these areas, whilst seemingly disparate, seek to inform the management of HVs, reduce of their impact on the network asset and/or provide a measurement mechanism for worn HV suspensions. A number of project management groups at the State and National level in Australia have been, and will be, presented with the results of the project that resulted in this thesis. This should serve to inform their activities applicable to this research. A number of HVs were tested for various characteristics. These tests were used to form a number of conclusions about HV suspension behaviours. Wheel forces from road test data were analysed. A “novel roughness” measure was developed and applied to the road test data to determine dynamic load sharing, amongst other research outcomes. Further, it was proposed that this approach could inform future development of pavement models incorporating roughness and peak wheel forces. Left/right variations in wheel forces and wheel force variations for different speeds were also presented. This led on to some conclusions regarding suspension and wheel force frequencies, their transmission to the pavement and repetitive wheel loads in the spatial domain. An improved method of determining dynamic load sharing was developed and presented. It used the correlation coefficient between two elements of a HV to determine dynamic load sharing. This was validated against a mature dynamic loadsharing metric, the dynamic load sharing coefficient (de Pont, 1997). This was the first time that the technique of measuring correlation between elements on a HV has been used for a test case vs. a control case for two different sized air lines. That dynamic load sharing was improved at the air springs was shown for the test case of the large longitudinal air lines. The statistically significant improvement in dynamic load sharing at the air springs from larger longitudinal air lines varied from approximately 30 percent to 80 percent. Dynamic load sharing at the wheels was improved only for low air line flow events for the test case of larger longitudinal air lines. Statistically significant improvements to some suspension metrics across the range of test speeds and “novel roughness” values were evident from the use of larger longitudinal air lines, but these were not uniform. Of note were improvements to suspension metrics involving peak dynamic forces ranging from below the error margin to approximately 24 percent. Abstract models of HV suspensions were developed from the results of some of the tests. Those models were used to propose further development of, and future directions of research into, further gains in HV dynamic load sharing. This was from alterations to currently available damping characteristics combined with implementation of large longitudinal air lines. In-service testing of HV suspensions was found to be possible within a documented range from below the error margin to an error of approximately 16 percent. These results were in comparison with either the manufacturer’s certified data or test results replicating the Australian standard for “road-friendly” HV suspensions, Vehicle Standards Bulletin 11. OBM accuracy testing and development of tamper evidence from OBM data were detailed for over 2000 individual data points across twelve test and control OBM systems from eight suppliers installed on eleven HVs. The results indicated that 95 percent of contemporary OBM systems available in Australia are accurate to +/- 500 kg. The total variation in OBM linearity, after three outliers in the data were removed, was 0.5 percent. A tamper indicator and other OBM metrics that could be used by jurisdictions to determine tamper events were developed and documented. That OBM systems could be used as one vector for in-service testing of HV suspensions was one of a number of synergies between the seemingly disparate streams of this project.

A irregularidade longitudinal dos pavimentos prejudica a qualidade de rolamento, aumenta os Custos Operacionais dos Veículos (COV) e reduz a vida útil do pavimento. Vários instrumentos têm sido desenvolvidos com o propósito de medir a irregularidade longitudinal dos pavimentos, no entanto, existem conflitos que envolvem as diferentes classes de equipamentos, com relação à acurácia, custos e produtividade, o que dificulta a coleta contínua de dados, importante para a alimentação de um Sistema de Gerência de Pavimentos (SGP). Recentemente, algumas pesquisas começaram a relacionar a irregularidade longitudinal dos pavimentos aos sinais fornecidos pelos sensores de movimento (acelerômetros) e GPS (Global Positioning System) pré-instalados em smartphones, devido ao seu baixo custo, fácil operação e alta produtividade. Entretanto, ainda existem dúvidas sobre a qualidade e a forma de aplicação desses dados. Neste estudo, foram realizados testes de vibração e levantamentos de campo com smartphones, em três trechos de pavimentos com diferentes níveis de irregularidade (baixo, médio e alto), nos quais foram medidos sinais de aceleração vertical por meio de um smartphone fixado ao painel de um veículo, trafegando em diferentes velocidades. Com esses dados, calcularam-se valores de RMSVA (Root Mean Square Vertical Acceleration), que foram confrontados com a irregularidade longitudinal dos pavimentos, medida em IRI (International Roughness Index), por meio do método de Nível e Mira. Os testes mostraram ser a taxa de aquisição de dados dos smartphones o principal fator a afetar sua aplicação para a avaliação da irregularidade longitudinal dos pavimentos. Ao considerar todas as faixas de irregularidade medidas, os valores de RMSVA apresentaram correlação positiva com o IRI, com coeficientes de correlação (R) entre 0,97 e 0,99 e repetitividade aceitável para levantamentos em nível de rede, com coeficientes de variação médios de 3 a 6%. Assim como indicado em pesquisas correlatas, conclui-se que os smartphones são uma alternativa viável para a avaliação da irregularidade longitudinal dos pavimentos, especialmente em países com restrições de investimentos no setor rodoviário, desde que sejam tomados os devidos cuidados na coleta e aplicação dos dados medidos por esses dispositivos.
The longitudinal pavement roughness affects the rolling quality, increases Vehicle Operating Costs (VOC) and reduces the pavement life. Several instruments have been developed for measuring longitudinal pavement roughness. However, there are conflicts involving different classes of equipment with respect to accuracy, costs and productivity, which complicate the continuous data collection, important for the Pavement Management Systems (PMS). Recently, some studies started to link longitudinal pavements roughness to the signals provided by motion sensors (accelerometers) and GPS (Global Positioning System) pre-installed on smartphones, due to its low cost, simple operation and high productivity. However, there are still doubts about the quality and the form of application of such data. In this study, vibration and field tests were performed with smartphones, in three pavement sections with different levels of roughness (low, medium and high), in which vertical acceleration signals were measured by a smartphone attached to a vehicle dashboard, traveling at different speeds. With these data, RMSVA values (Root Mean Square Vertical Acceleration) were calculated, which were compared with longitudinal pavement roughness, measured in IRI (International Roughness Index) through the Level and Rod method. The tests showed to be the data acquisition rate of smartphones the main factor affecting its application for the evaluation of longitudinal roughness of pavements. When considering all roughness ranges measured, RMSVA statistics showed a positive correlation with IRI, with correlation coefficients (R) between 0.97 and 0.99 and acceptable repeatability for network-level surveys, with average coefficient of variation of 3 to 6%. As indicated in related research, it was concluded that smartphones are a viable alternative for the evaluation of longitudinal pavements roughness, especially in countries with investment restrictions in the highway segment, if the data are collected and explained properly.

Le processus d'érosion éolienne peut entraîner plusieurs conséquences environnementales: la désertification, la dégradation des sols, la pollution de l'air, etc. Cette dernière est liée aux émissions de particules de matériaux granulaires couramment trouvés sur des sites industriels tels que le minerai et le charbon. La distribution granulométrique de ces matériaux consiste habituellement en un mélange d'une large gamme de diamètres, qui comprennent des particules plus grosses qui ne sont pas érodables même avec de fortes rafales de vent. Les particules non érodables jouent un rôle protecteur pour les particules érodables, en recouvrant la surface et en réduisant ses émissions. L'objectif principal de cette thèse est d'estimer plus précisément les émissions dues à l'érosion éolienne compte tenu de l'influence du pavage causée par des particules non érodables. Un modèle analytique a été proposé pour quantifier les émissions des lits de particules et des tas de stockage avec une large distribution granulométrique. Les effets du processus de pavage sont incorporés dans le modèle par la diminution de la vitesse de frottement moyenne sur la surface érodable puisque les particules non érodables s'accumulent. Des travaux antérieurs ont défini une relation mathématique entre l'évolution de la vitesse de frottement sur la surface érodable et la géométrie des éléments de rugosité. Néanmoins, l’equation n'est valable que pour des taux de couverture de particules non érodables limités. Des simulations numériques ont été effectuées dans ce travail pour étendre cette relation afin d'inclure d'autres cas rencontrés dans des situations réelles (avec de plus grandes quantités de particules non érodables). Le modèle d'émission proposé décrit la relation entre la valeur minimale de la vitesse de frottement (à laquelle les émissions cessent), en tirant parti des résultats numériques, et la profondeur finale érodée du lit, qui fournit à son tour la masse émise. Des expériences en soufflerie ont été réalisées afin de mieux comprendre le phénomène de pavage et estimer les émissions d'un lit de particules contenant une distribution de taille bimodale. Les résultats expérimentaux ont également été utilisés pour valider la modélisation, y compris la masse émise globale et les caractéristiques finales de la surface du lit. Un bon accord a été trouvé entre les résultats expérimentaux et modélisés pour les émissions globales et la profondeur de lit érodé. Le modèle d'érosion a été étendu pour l'application dans les tas de stockage. Dans ce cas, l'érodabilité des particules est plus complexe, puisque la vitesse de frottement et les conditions de seuil ne sont pas spatialement homogènes. L'idée du modèle était de subdiviser le tas en isosurfaces dans lesquelles les conditions de seuil et la vitesse de frottement sont constantes, et traiter chacune de ces zones comme une source différente où le modèle d'émission peut être appliqué. Des expériences en soufflerie ont été réalisées afin d'estimer les émissions d'un tas de sable contenant une distribution de taille bimodale. Les résultats modélisés et expérimentaux ont été comparés pour la configuration d'un tas isolé et un bon accord a été trouvé entre la masse émise estimée et mesurée. L'impact de la présence d'un bâtiment et d'un tas de stockage parallèle successif sur l'émission globale de particules a également été évalué. Des expériences en soufflerie et des simulations numériques ont été effectuées pour plusieurs configurations, en évaluant les effets de: (i) l'orientation du vent, (ii) la vitesse du vent, (iii) la distance entre l'obstacles et (iv) la quantité de particules non érodables. Il a été constaté que les interférences de l'écoulement entre les obstacles augmentent les émissions. Par conséquent, toutes les perturbations du vent ont un impact significatif et doivent être prises en compte dans l'estimation et la modélisation des émissions de poussières
Wind erosion process can lead to several environmental consequences: desertification, land degradation, air pollution, etc. This last one is related to particulate matter emissions from granular materials commonly found on industrial sites, such as ore and coal. The particle size distribution of these granular materials usually consist of a mixture of a wide range of diameters, which include larger particles that are non-erodible even with strong gusts of wind. The non-erodible particles play a protective role for erodible particles, paving the surface and reducing emissions. The main objective of this thesis is to estimate more accurately emissions due to wind erosion considering the influence of the pavement caused by non-erodible particles. An analytical model was proposed to quantify emissions from particle beds and stockpiles with a wide size distribution. The effects of pavement process are incorporated in the model through the decrease of the mean friction velocity on the erodible surface as the non-erodible particles accumulate. Previous works have defined a mathematical relation between the evolution of the friction velocity over the erodible surface and the geometry of the roughness elements. Nonetheless, the formulation was only valid to limited cover rates of non-erodible particles. Numerical simulations were carried out in this work to extend the formulation in order to include other cases encountered in real situations (with larger amounts of non-erodible particles). The proposed emission model describes the relationship between the minimum value of friction velocity (at which emissions cease), taking advantage of the numerical findings, and the final eroded depth of the bed, which in turn, provides the emitted mass. Wind tunnel experiments were carried out in order to better understand the pavement phenomenon and estimate emissions from a bed of particles containing a bimodal size distribution. The experimental results were also used to validate the modeling, including the global emitted mass and the final characteristics of the bed surface. A good agreement was found between experimental and modeled results for the global emissions and the bed eroded depth. The erosion model was extended for application in stockpiles. In this case, the erodibility of the particles is more complex as the friction velocity and the threshold conditions are not spatially homogeneous. The idea of the model was to subdivide the pile in isosurfaces in which the threshold conditions and the friction velocity are constant and then treat each one of these areas as a different source where the emission model can be applied. Wind tunnel experiments were carried out in order to estimate emissions from a sand pile containing a bimodal size distribution. The modeled and the experimental results were compared for the configuration of an isolated stockpile and a good agreement was found between the estimated and the measured emitted mass. The impact of the presence of a building and a successive parallel stockpiles on the overall particles emission was also evaluated. Wind tunnel experiments and numerical simulations were carried out for several configurations evaluating the effects of: (i) main wind flow orientation, (ii) wind flow velocity, (iii) gap between the obstacle and (iv) amount of non-erodible particles. It was found that the flow interferences between the obstacles increase emissions. Therefore, all wind perturbations have a significant impact and have to be accounted in dust emission estimation and modeling
O processo de erosão eólica pode levar a várias consequências ambientais: desertificação, degradação da terra, poluição do ar, etc. Esta última está relacionada com as emissões de partículas provenientes de materiais granulares comumente encontrados em indústrias, como minério e carvão. A distribuição granulométrica destes materiais normalmente consiste em uma mistura com uma ampla gama de tamanhos, incluindo partículas maiores que não são erodíveis mesmo com fortes rajadas de vento. As partículas não erodíveis desempenham um papel protetor para as partículas erodíveis, pavimentando a superfície e reduzindo as emissões. O objetivo principal desta tese é estimar com maior acurácia as emissões devidas à erosão eólica considerando a influência da pavimentação causada pelas partículas não-erodíveis. Um modelo analítico foi proposto para quantificar as emissões de leitos de partículas e pilhas com ampla distribuição granulométrica. Os efeitos do processo da pavimentação são incorporados no modelo por meio da diminuição da velocidade de fricção média na superfície erodível à medida que as partículas nãoerodíveis se acumulam. Trabalhos anteriores definiram uma relação matemática entre a evolução da velocidade de fricção na superfície erodível e a geometria dos elementos rugosos. No entanto, a formulação é válida apenas para limitadas taxas de cobertura de partículas não-erodíveis (< 12%). Simulações numéricas foram realizadas neste trabalho para estender a formulação de modo a incluir outros casos encontrados em situações reais (com maiores quantidades de partículas nãoerodíveis). O modelo de emissão proposto descreve a relação entre o valor mínimo da velocidade de fricção (para qual as emissões cessam), utilizando os resultados numéricos, e a profundidade final erodida do leito, que, por sua vez, fornece a massa emitida. Experimentos em túnel de vento foram realizados para melhor compreender o fenômeno da pavimentação e estimar as emissões de um leito de partículas contendo uma distribuição granulométrica bimodal. Os resultados experimentais foram também utilizados para validar a modelagem, incluindo a massa global emitida e as características finais da superfície do leito. Uma boa concordância foi encontrada entre os resultados experimentais e modelados para as emissões globais e a profundidade erodida do leito. O modelo de erosão foi estendido para aplicação em pilhas de estocagem. Neste caso, a erodibilidade das partículas é mais complexa, uma vez que a velocidade de fricção e as condições de limiar não são espacialmente homogêneas. A ideia do modelo é subdividir a pilha em isosuperfícies em que as condições de limiar e a velocidade de fricção são constantes e, em seguida, tratar cada uma dessas áreas como uma fonte diferente onde o modelo de emissão pode ser aplicado. Foram realizados ensaios experimentais em túnel de vento para estimar as emissões de uma pilha de areia contendo uma distribuição de tamanho bimodal. Os resultados experimentais e modelados foram comparados para a configuração de uma pilha isolada (orientada 60 e 90° em relação a direção do escoamento) e uma boa concordância foi encontrada entre a massa estimada e a emitida. O impacto na emissão da presença de um edifício e de uma pilha de estocagem sucessiva também foi avaliado. Experimentos em túnel de vento e simulações numéricas foram realizados para várias configurações avaliando os efeitos de: (i) orientação do vento, (ii) velocidade do vento, (iii) espaçamento entre os obstáculos e (iv) quantidade de partículas não erodíveis. Verificou-se que as interferências do escoamento entre os obstáculos aumentam as emissões. Portanto, todas as perturbações no escoamento têm um impacto significativo e devem ser contabilizadas na estimativa e modelagem de emissões de partículas

O objetivo desta tese de doutorado foi desenvolver modelos de previsão de desempenho de pavimentos asfálticos para a malha rodoviária do Estado da Bahia. Os modelos de desempenho foram desenvolvidos para pavimentos em concreto asfáltico usinado a quente e em tratamento superficial duplo. Foram utilizadas informações de um banco de dados de gerência de rodovias do DERBA, coletados em 2004, e foram coletados dados complementares de irregularidade longitudinal em 2009, após o desenvolvimento de um planejamento fatorial específico para essa finalidade. Foram utilizadas duas formas de análise estatística dos dados para avaliar a significância dos fatores e definir os parâmetros dos modelos de desempenho: a Análise Exploratória de Dados (AED) e a Análise da Variância (ANOVA). Os fatores considerados foram a idade do pavimento, o tráfego e a pluviometria e os resultados da análise exploratória de dados corroboraram os resultados encontrados pela análise da variância, tanto em relação aos efeitos dos fatores como das interações. Os modelos de previsão do desempenho foram desenvolvidos para as variáveis dependentes Índice de Condição do Pavimento Flexível (ICPF) e Área Total de Trincas (ATT), para os pavimentos em concreto asfáltico usinado a quente, e os modelos de previsão de desempenho de Área de Desgaste (ADesg) e Irregularidade Longitudinal (IRI BA), para os trechos em tratamento superficial duplo. Para a irregularidade longitudinal, também foram desenvolvidos modelos de desempenho em separado, para regiões de clima semiárido a seco (IRIBAs) e clima subúmido a úmido (IRI BAÚ). Para a verificação da adequação dos modelos de previsão de desempenho foram utilizadas a análise de resíduos, o coeficiente de correlação (r) e o coeficiente de determinação (\'R POT.2\'). Os modelos de desempenho, desenvolvidos neste trabalho para a Área Total de Trinca (ATT) e para a Irregularidade Longitudinal, foram comparados com modelos de desempenho empíricos, utilizados em programas de gerência de pavimentos por organismos rodoviários, do Brasil e do exterior, e apresentaram melhores resultados. O modelo de Irregularidade Longitudinal (IRI BA) para a rede de rodovias em tratamento superficial duplo também foi comparado com modelo desenvolvido pelo Departamento de Infraestrutura de Transportes da Bahia - DERBA, com base em levantamentos para a priorização de trechos candidatos a atividades de manutenção e reabilitação, e apresentou melhor ajuste aos dados observados. No entanto, para que sejam obtidos ainda melhores resultados, quanto à previsão de desempenho dos pavimentos da rede de rodovias pavimentadas do Estado da Bahia, é necessário que sejam realizados novos levantamentos para alimentação do banco de dados, sugerindo-se estudos complementares que incluam fatores que não puderam ser considerados neste trabalho, como a capacidade estrutural, por exemplo. Recomenda-se que o método utilizado neste trabalho, baseado no planejamento fatorial, na Análise Exploratória de Dados e na Análise de Variância, seja repetido, pois se mostrou capaz de reduzir os custos da coleta de dados sem comprometer a precisão e acurácia dos modelos de desempenho obtidos.
The objective of this thesis was to develop performance prediction models for asphalt pavements in the State of Bahia. The performance models were developed for hot-mix asphalt (HMA) and double surface treatment (ST). Information was obtained from a database maintained by DERBA (State of Bahia Department of Transportation), with data collected in 2004, and from additional collection of data, mainly of pavement roughness, performed in 2009 and that was based on an experimental design for this specific purpose. Two statistical analyses were used to assess the significant factors and define the parameters of the performance models: Exploratory Data Analysis (EDA) and Analysis of Variance (ANOVA). The factors considered were age of the pavement, traffic volume and rainfall, and the results of the exploratory data analysis corroborated the results found by the analysis of variance, both in relation to the effects of factors such as of their interactions. The performance prediction models were developed for the dependent variables Pavement Condition Index (PCI) and Area of Total Cracks (ATC) for HMA pavements, and Raveling (R) and roughness (IRI BA) for ST pavements. For roughness, performance models were also developed considering, separately, two climate conditions: semiarid to arid (IRI BAa) and sub-humid to humid (IRI BAh). Residue analysis and calculation of correlation coefficient (r) and coefficient of determination (\'R POT.2\') were performed to verify the adequacy of performance prediction models. The performance models developed in this work for Area of Total Cracks (ATC) and roughness (IRI) were compared with empirical performance models used for pavement management in Brazilian and foreign highway agencies, and they presented the best results. The performance model for roughness (IRI BA) in ST pavements was also compared to a prediction model developed by DERBA using data collected by a maintenance and rehabilitation activities prioritization program and it presented the best fit to the observed data. However, to obtain even better results regarding the performance prediction of asphalt pavements in the State of Bahia, it is necessary to conduct new field surveys to feed the database and be used in further studies that include factors that could not be considered in this work, as structural capacity, for example. It is recommended that the method used in this work, based on factorial design, Exploratory Data Analysis and ANOVA, be repeated, because it proved capable of reducing the costs of data collection without compromising precision and accuracy of the obtained performance prediction models.

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.

The main aim of this thesis paper is to determine the influence of physical and mechanical indices of asphalt concrete pavement on the operational properties of Lithuanian highway pavement as well as on the functional lifetime of road pavement. The analysis of pavement condition of Lithuanian highways is presented. The classification regarding the damage and deformation of material used for the construction of asphalt concrete pavement and of road pavement structure is provided. The causes of the afore-mentioned damages and deformations are also explained and rectification methods which can be applied to eliminate these causes are described. The operational conditions of the road pavement and its structure as well as the applicable methods are theoretically justified. In addition, the physical and mechanical indices of asphalt concrete pavement of the highway Vilnius – Kaunas - Klaipėda (A1) and of pavement roughness in accordance with IRI research data are given. The analysis of the data allowed the correlation between the two items to be determined. The research material was processed by means of the statistical software package “Statgraphics 5.1 Plius”. Standardized physical and mechanical indices of asphalt concrete pavement which affect the functional lifetime of pavement structure are presented. The conclusions and recommendations are provided.

La presente investigación lleva como título “Propuesta de Gestión para mantener la Rugosidad dentro de los Niveles de Servicio del contrato de concesión”. La investigación se enfoca en dar una alternativa de gestión que asegure mantener los niveles de servicio en lo referente a la calidad del pavimento cuando la carretera se encuentra en estado de conservación reduciendo el costo que se va a invertir en años futuros teniendo como base datos obtenidos desde el año 2010 al 2015. El deterioro prematuro del pavimento se ve afectado cuando no se tiene un plan de conservación adecuado que conlleve a programar y ejecutar actividades de mantenimiento rutinario y periódico con la finalidad de mantener los niveles de servicio en carreteras concesionadas. Esto conlleva que la condiciones de las redes viales se encuentren por debajo de lo que resulta deseable y conveniente, presentando un ciclo vicioso de la vía (Construcción – Abandono – Destrucción – Reconstrucción). La investigación es de tipo cuantitativo no experimental, descriptivo, correlacional y explicativo. Su diseño es longitudinal ya que tiene como referencia datos obtenidos desde el año 2010 al 2015. Se analizaron dos propuestas de gestión de conservación vial teniendo como base los datos procesados de los años 2010 al 2015 para obtener una alternativa que logre cumplir con el objetivo principal de ésta investigación. Finalmente se concluye que es posible formular una propuesta de gestión vial que permita optimizar el presupuesto de mantenimiento en los años proyectados conservando la calidad del pavimento. Analizando la posibilidad y conveniencia de postergar el mantenimiento periódico considerando que los valores de rugosidad, estén dentro de los niveles admisibles reemplazándolo por intervenciones de menor costo. This research is entitled "Management Proposal to maintain the roughness within Service Level concession contract." The research focuses on providing an alternative management to ensure maintain service levels in terms of the quality of the pavement when the road condition in reducing the cost to be reversed in future years on the basis of data from 2010 to 2015. Premature pavement deterioration is affected when there is no proper conservation plan that may lead to program and implement activities of routine and periodic maintenance in order to maintain service levels in toll roads. This means that the conditions of the road networks are below what is desirable and convenient, featuring a vicious cycle route (Construction - Abandonment - Destruction - Reconstruction). The research is not experimental, descriptive, correlational and quantitative explanatory. Its design is longitudinal and whose reference data from 2010 to 2015. Two proposals for road maintenance management on the basis of processed data for the years 2010 to 2015 for an alternative that would meet the main objective of this research is analyzed. Finally we conclude that it is possible to formulate a proposal for road management for optimizing the maintenance budget in projected years preserving the quality of the pavement. Analyzing the possibility and desirability of postponing regular maintenance considering that the roughness values, are within acceptable levels by replacing lower-cost interventions.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
As pontes rodoviárias mistas (aço-concreto) estão sujeitadas às ações dinâmicas variáveis, por exemplo, devido ao tráfego de veículos sobre a superfície irregular do pavimento. Estas ações dinâmicas podem gerar a nucleação de fraturas ou mesmo a sua propagação sobre a estrutura. A correta consideração desses aspectos objetivou o desenvolvimento de uma metodologia de análise, com a finalidade de avaliar os níveis dos esforços e tensões oriundos do tráfego dos veículos sobre a superfície irregular do pavimento e, bem como, proceder uma verificação à fadiga de obras de arte rodoviárias em aço e mistas (aço-concreto). Para tal, as técnicas para a contagem de ciclos de tensão e a aplicação das regras de dano acumulado foram analisadas através de curvas do tipo S-N, associadas a diversas normas de projeto. A ponte rodoviária mista (aço-concreto) investigada neste estudo é constituída por quatro vigas de aço longitudinais e por um tabuleiro de concreto armado. O modelo numérico-computacional, desenvolvido para a análise dinâmica da ponte, foi concebido com base em técnicas usuais de discretização através do método dos elementos finitos. Simulam-se as almas das vigas de aço e as lajes de concreto do tabuleiro através de elementos finitos de casca. As mesas dessas vigas, transversinas e os enrijecedores são modelados por elementos de viga tridimensionais. Os veículos são representados a partir de sistemas "massa-mola-amortecedor". O tráfego dessas viaturas é considerado mediante a simulação de comboios semi-infinitos, deslocando-se com velocidade constante sobre a ponte. As conclusões da presente investigação versam acerca da vida útil de serviço dos elementos estruturais de pontes mistas (aço-concreto).
Steel and composite highway bridges (steel-concrete) are currently subjected to dynamic actions, for example, variable magnitude due to vehicles traffic on the deck rough pavement. These dynamic actions can generate the fractures nucleation or even their propagation on the structure. The correct consideration of these aspects pointed out to an analysis methodology developed, in order to evaluate the stresses through a dynamical analysis on highway bridge decks, due to vehicles crossing on the irregular pavement surfaces and to proceed a fatigue verification from Steel and composite highway bridges (steel-concrete). The stress cycles counting techniques and the cumulative damage rules application had been analyzed through S-N curves associated with diverse projects norms. The steel and composite highway bridge (steel-concrete), investigated in this study, is constituted by four longitudinal steel beams and a composite deck. The computational model, developed for the bridge dynamic analysis , adopted the usual mesh refinement techniques present in finite element method simulations. The beam web thickness was represented by shell finite elements. The beam top and bottom flange and the longitudinal and vertical stiffeners were simulated by three-dimensional beam elements, where flexural and torsion effects were considered. The bridge concrete slab was simulated by shell finite elements. The vehicles are represented from "mass-spring-damper" systems. The traffic of these vehicles is considered as a simulation of half-infinite convoys dislocating with constant speed on the bridge. The present study conclusions concerning steel and composite highway bridges (steel-concrete) structural elements service life.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
As pontes rodoviárias metálicas e mistas (aço-concreto) são submetidas a um grande número de carregamentos repetitivos de diferentes magnitudes, ao longo do tempo. Estas ações dinâmicas podem causar a nucleação de fraturas ou mesmo a propagação destas sobre o sistema estrutural. A depender da magnitude, estes efeitos podem comprometer o sistema estrutural e a sua confiabilidade, além de reduzir a vida útil das pontes. Assim sendo, neste trabalho de pesquisa foi investigada a resposta dinâmica de uma ponte mista (aço-concreto), simplesmente apoiada, com vão de 40,0 m, submetida ao tráfego de veículos sobre a superfície irregular do pavimento. Para tal um modelo numérico representativo do sistema estrutural foi desenvolvido com base no emprego do programa ANSYS, por meio do uso de técnicas usuais de discretização, via método dos elementos finitos. Um estudo paramétrico foi desenvolvido para identificar, de forma qualitativa e quantitativa, o efeito das irregularidades do pavimento sobre o comportamento dinâmico da ponte mista investigada. Em seguida, a verificação do projeto à fadiga do sistema misto foi realizada, com base no emprego do algoritmo de contagem de ciclos Rainflow e em curvas S-N associadas às principais normas de projeto sobre o tema. As conclusões deste trabalho de pesquisa alertam aos engenheiros estruturais para a possibilidade concreta acerca do aumento do dano por fadiga, relacionado às ações dinâmicas de veículos trafegando sobre o tabuleiro de pontes em aço e mistas (aço-concreto).
Steel and steel-concrete composite highway bridges are currently subjected to dynamic actions with variable magnitudes due to the action of vehicles crossing on the deck. These dynamic actions can generate the nucleation of fractures or even their propagation in the structures. Depending on the magnitude, these effects can compromise the structural system response and the reliability, which may also lead to a reduction of the expected bridge service life. This way, the dynamic response of a steel-concrete composite bridge spanning 40 m was investigated in this work. The computational model, developed for the composite bridge dynamic analysis, adopted the usual mesh refinement techniques present in finite element method simulations, and was implemented in the ANSYS program. A parametric study was performed to identify the effect of vehicle speed and roughness pavement on the investigated bridge dynamic behaviour. The proposed methodology for evaluate the bridge service life to fatigue was based on a linear cumulative damage rule, Rainflow-counting algorithm and S-N curves from main design codes. Results of a parametric analysis are presented to verify the extension of the dynamical effects on highway bridges due to vehicles crossing on the irregular pavement surface. The main conclusions of this work focuses on alerting structural engineers to the possibility of increase of fatigue damage, related to steel and composite highway bridges when subjected to vehicle dynamic actions.

碩士
國立中央大學
土木工程研究所
92
It’s most important to check and accept the roughness of new build or maintained pavements in pavement management system. It’s not only to concern about comfortable and safety to drive a vehicle but also decide using years of pavement. Because of the roughness of Pavement was influenced which for the most part by technique of construction and control of quality. Roughness was a key point when pavements build to finish. Although the roles which about the standard of roughness to check and accept was collected in the standard of pavement construct in our country, but the ways of survey was concluded in early periods. The apparatus to adopt most are 3m straight and Hi-Lo Detector. Mainly of index are judge by using the standard deviation of roughness. It’s difficult to describe the influence of comfortable to drive a vehicle. And it does usually survey by sampling way in present standards. So it’s hard to describe the roughness in whole line of pavement completely. In Part of apparatus to examine, the 3m straight and Hi-Lo Detector are not only waste a lot of time but also strenuous effort. It’s also can’t connect with the world current by using standard deviation of roughness. For this reason, it’s important to find the way which is efficiently to examine and good communicated index to evaluate and then to re-edit the standard to check and accept to fit in with present. So this study tries to develop the intelligent vehicle for pavement survey by oneself. It can improve the problem which existed in the apparatus of survey roughness. In addition, consult the adventures of the standard to check and accept of the pavement roughness in the world, and collect roughness data by survey apparatus to draw up the International Roughness Index (IRI) as standard of roughness by using statistics analysis ways.

abstract: Pavement management systems and performance prediction modeling tools are essential for maintaining an efficient and cost effective roadway network. One indicator of pavement performance is the International Roughness Index (IRI), which is a measure of ride quality and also impacts road safety. Many transportation agencies use IRI to allocate annual maintenance and rehabilitation strategies to their road network. The objective of the work in this study was to develop a methodology to evaluate and predict pavement roughness over the pavement service life. Unlike previous studies, a unique aspect of this work was the use of non-linear mathematical function, sigmoidal growth function, to model the IRI data and provide agencies with the information needed for decision making in asset management and funding allocation. The analysis included data from two major databases (case studies): Long Term Pavement Performance (LTPP) and the Minnesota Department of Transportation MnROAD research program. Each case study analyzed periodic IRI measurements, which were used to develop the sigmoidal models. The analysis aimed to demonstrate several concepts; that the LTPP and MnROAD roughness data could be represented using the sigmoidal growth function, that periodic IRI measurements collected for road sections with similar characteristics could be processed to develop an IRI curve representing the pavement deterioration for this group, and that pavement deterioration using historical IRI data can provide insight on traffic loading, material, and climate effects. The results of the two case studies concluded that in general, pavement sections without drainage systems, narrower lanes, higher traffic, or measured in the outermost lane were observed to have more rapid deterioration trends than their counterparts. Overall, this study demonstrated that the sigmoidal growth function is a viable option for roughness deterioration modeling. This research not only to demonstrated how historical roughness can be modeled, but also how the same framework could be applied to other measures of pavement performance which deteriorate in a similar manner, including distress severity, present serviceability rating, and friction loss. These sigmoidal models are regarded to provide better understanding of particular pavement network deterioration, which in turn can provide value in asset management and resource allocation planning.
Dissertation/Thesis
Masters Thesis Civil Engineering 2016

碩士
國立中央大學
土木工程研究所
93
Roughness is a vestige lengthways the section rises and falls of fluctuation quantity of the road surface, which influence the quality of the road to drive very much. The road of the roughness faces to drive the comfort quickly can raise the road service quality. Therefore, people who use the road will not feel well if there is high and low to rise and fall the serious road to make the vehicle produced the continuous vibration. Furthermore, because of need to insure the transportation security and reduce the drive speed, it not only makes the service level and efficiency of the road reduced consumedly, but also cause the vehicle excessiveness of vibrate, the fuel consumes and reduce the vehicle service life consumedly which because the road faces not roughness. In part of apparatus to examine, the 3m straight and Hi-Lo Detector are not only waste a lot of time but also strenuous effort. It’s also not suitable in network level by using standard deviation of roughness. Although introduce an examination instrument in recent years, still belong to very few parts of units to own, and purchased the cost high in the early years. Therefore, compare to the promotion at the home advanced of the instrument examines and internationalizes the index sign the usage up is really difficult problem. So this study tries to develop the intelligent vehicle for pavement survey by oneself. It can improve the problem which existed in the apparatus of survey roughness. Even carry on a series of identification procedures to this system, among them include identifications such as identification and the international roughness index sign stability etc. of various instruments of this system. The above procedure all consults the foreign related standard to take into the identification. By the above identification procedure, in addition to canning increase the credibility of this examination system, also can improve the not easily seen problem of an examination instrument results. All intelligent vehicles for pavement survey by oneself are not passing the accredited of Chinese National Laboratory Accreditation (CNLA). Although there is keep doing the related identification procedure, it still in the research development stage. So this research hopes to first step draws up the CNLA certification procedure relevant document and operates the manual...etc. to identify the procedure by many items, matching the foreign related standard. Looking forward to make the intelligent vehicle for pavement survey which developed by oneself can pass the certification permission. This research with originally intelligent spread to face to examine the car to collect Taoyuan County inshore ll country a data, after taking in to statisticsed the analysis, and inquire into the not flat reason of causing the road.And combine the Videologging system of the Institute of Transportation development. Take into the collections in the lieutenant general all image datas with basic roads of the examination process. With continues image perhaps by the photograph, can use the stranger or two usage situation in the side landses of the related position and road of the entire content, various facilities that protect the unit to the road's segment. Didn't need to the scene, can carry on the first step the inspection the road to follow the line condition. This research collects the protect data of country way of three years in Taoyuan County. And The covariance protects the area size、Protecting the summary calculates the budget、protect the way and protect to maintain cost etc. Combining an examination data carries on the country way to protect the threshold value, The result is 6.65 m/km. Apply above all data in spread to face in the pavement management system. Expect to have to promote to inshore road quality in Taoyuan County, all use the stranger and all can have to go the car environment sooner and soon and more comfortablely.

碩士
國立成功大學
土木工程學系專班
94
ABSTRACT Pavement roughness affects the comfort of driving on the road. A good quality for the roughness of the road could provide a better service as well as a longer PVT lift. Thus, pavement roughness can be a good judgment for the performance of the road construction. However, the major factors influeniry the roughness of the road construction are by the workmanship and the quality control of the road contractor. Therefore, to construct an adjustable payment framework system according to the degree of road pavement roughness would be a good solution for a better road. The first step is collecting the data for International Roughness Index (IRI) of the provincial roads in Taiwan. The Monte carol simulation process is used to predict the life cycle costs (Lthe CC). According to the existed models, we can compare Kaoshiung case with that of Pingtung case. In Kaoshiung case, without any special damage cause by construction or others paving can serve about 12.6 years; In Pingtung case, although it has higher rate of deteriorate, however, it also has a lower initial pavement roughness. In the end, the service period of Pingtung is three years more then that of Kaoshiung. The main concept of this paper is first, using existed ground IRI index and the Monte carol simulation process to modify an initial pavement IRI index. Second, by the concept of lift span coast to except its service life span and pay adjustment and pay factor. Finally, through the Web function to process a reliability analysis. Using such concept, this paper has successfully model a Kaoshiung road pavement construction case for its ten years lift span and has only 45.8% to accrue 47.5% different. The purpose of this paper is to summarize a reasonable method for modeling the pavement life-cycle cost. The modeling method would help to create a fair and reasonable process according to the rating of the design roughness of road pavement for both the highway agency and the contractor. Using by reasonable pay adjustment (PA) and reward for the result of construction, the agency would improve the quality of road construction.

碩士
國立成功大學
土木工程學系碩博士班
91
Dynamic load is the most important factor for stress prediction and life assessment of pavements. The dynamic effect cannot be resolved with either isolated pavement system or vehicle kinematic formation because vehicles and pavements are coupled as an interaction system. This article describes simulation of the coupled system and analysis of the impact force associated by moving vehicle and pavement roughness. A quarter-car model was built with a linear spring and a mass element as half of wheel axle, and a spring-dashpot system as vehicle suspension connecting the lumped car mass and the wheel axle. The concrete pavement was composed of 20-node brick elements resting on springs and dashpots. The pavement elevation was input according to sinusoidal curve to simulate surface irregularities. The model was successfully validated with theoretical solutions and was further expanded to a S122 tractor-trailer model. The dynamic effect and coupled interaction were thoughtfully discussed. Keyword: ABAQUS, vehicle-road interaction, dynamic load, rigid pavement, finite element.

abstract: Pavement preservation is the practice of selecting and applying maintenance activities in order to extend pavement life, enhance performance, and ensure cost effectiveness. Pavement preservation methods should be applied before pavements display significant amounts of environmental distress. The long-term effectiveness of different pavement preservation techniques can be measured in terms of life extension, relative benefit, and benefit-cost ratio. Optimal timing of pavement preservation means that the given maintenance treatment is applied so that it will extend the life of the roadway for the longest possible period with the minimum cost. This document examines the effectiveness of chip seal treatment in four climatic zones in the United States. The Long-Term Pavement Performance database was used to extract roughness and traffic data, as well as the maintenance and rehabilitation histories of treated and untreated sections. The sections were categorized into smooth, medium, and rough pavements, based upon initial condition as indicated by the International Roughness Index. Pavement performance of treated and untreated sections was collectively modeled using exponential regression analysis. Effectiveness was evaluated in terms of life extension, relative benefit, and benefit-cost ratio. The results of the study verified the assumption that treated sections performed better than untreated sections. The results also showed that the life extension, relative benefit, and benefit cost ratio are highest for sections whose initial condition is smooth at the time of chip seal treatment. These same measures of effectiveness are lowest for pavements whose condition is rough at the time of treatment. Chip seal treatment effectiveness showed no correlation to climatic conditions or to traffic levels.
Dissertation/Thesis
M.S. Civil Engineering 2012

碩士
國立成功大學
資源工程學系碩博士班
101
The current way of analyzing pavement roughness is manually operating the 3m-straight edge or the Hi-Lo detector. The efficiency of such measurement is only 0.8 kilometer per hour. It wastes lots of time and very laborious, does not meet the requirement of Taiwan’s situation: densely populated and intensive distribution of road. Mobile LiDAR has been introduced to Taiwan recently, comparing to traditional manual measurement, it has more advantages like accessing road information quickly, high accuracy data and without human operating error. The efficiency could reach 40 kilometers per hour that could replace traditional manual measurement completely. Based on the Optech Lynx mobile LiDAR system specifications, mobile LiDAR system has 8 mm system error. This error is unacceptable for the investigation of road roughness, need to be reduced to 6mm by data post-processing. In this study, we use two laser scanner’s point cloud data of mobile LiDAR system to process road extraction, data preprocessing and strip adjustment. Then testing the effection from different speed, turning angle and nature of pavement. The results shows when measuring vehicle’s speed is less than 60km/hr, turning angle is less than 40 degrees and driving on a generally flat road, strip adjustment will reduce systematic errors by half, could export the pavement data with enough precision for analyzing pavement roughness at Taiwan.

碩士
國立成功大學
土木工程學系碩博士班
97
Roughness of roads causes pavement stress fluctuation along the road. However, the dynamic effects were not taken into account in most pavement design and researches. To investigate the influences of roadway roughness on pavement stresses, this study developed a coupled system consisting of a quarter-car model and an equivalent one-degree mass-spring pavement model. The coupled system also incorporated measured road profiles. By means of transfer function in frequency domain, the deflections and stresses of pavements were computed in seconds. The results were validated by comparing with Westergaard solutions satisfactorily. It was found that the critical roughness, which might cause extreme responses, is related to the vehicle speed, suspension design of vehicles. The maximum tension at the bottom of pavements also depends on the slope of road profiles. In addition, the study demonstrates the correlation between two road roughness classification indices, IRI and ISO. It was also found that disturbance due to model boundary affects simulation results significantly.

碩士
國立成功大學
土木工程學系
102
In Taiwan, due to the rapid increased highway network in the past ten years as well as aging of the highway infrastructure, Taiwan Area National Freeway Bureau (TANFB) has encountered great challenge to maintain their highway network in good condition. The major challenge for pavement engineers is to maintain good condition of roadway with least costs. In order to estimate maintenance cost for whole highway network, it is important to know when and how much percent of pavement network fails in the future. In this study, two reliability analysis approaches (failure-time analysis as well as degradation analysis) were performed to estimate the network level pavement service life based on international roughness index (IRI) data collected from the outer lane of Taiwan’s national freeway network during 2006 to 2010. The pavement maintenance threshold of 3, 3.5, and 4 m/km and failure probability 25 percent were used to estimate the pavement service life for pavements in the north, central and south district of national freeway system. The results of failure-time analysis shown that the predicted pavement service life for the north, central and south district of southbound freeway one are 4.9, 4.6 and 1.6 years; of the northbound freeway one are 2.5, 4.8 and 0.8 years; of the southbound freeway three are 2.6, 2.4 and 1.6 years, and of the northbound freeway three are 2.4, 2.6 and 2.9 years. For the degradation analysis, the estimated pavement service life of north, central and south district of freeway one southbound are 2.6, 3.4 and 1.6 years; of freeway one northbound are 2.5, 3.8 and 1.2 years; of freeway three southbound are 3.4, 4.3 and 1.3 years; and of freeway three northbound are 3.2, 3.4 and 2.4 years. In general, both approaches estimate pavement service life of 2 to 5 years that is similar to the maintenance frequency currently adopted by the expert engineers in the TANFB.

博士
國立中央大學
土木工程研究所
98
Since 1999, there were a lot of studies about pavement management system, but unfortunately we did not use it in real maintainance works. The purpose of this study is that we want to integrate three kinds of important technique into intelligent survey vechiel, and try to think a standard operation for pavement survey. We did a lot of tests and verified about the pavement roughness measurement system in accordance with ASTM E950 and AASHTO PP49. We find that all results of test is conforming the standard of ASTM and AASHTO. Roughness is a very important performance indicator in pavement maintenance management systems. The international rough index of indicators was used as the core of roughness measuring of degree gradually in recent years domestically, but to predict a smooth degree of indicators the method is set up differently as there is a different prediction indicator because the theoretical foundation is different.We predicts the deteriorationof IRI by different ways, including grey forecast, multiple regression. We also try to use data minning technique to find a rule between unified condition index and pavement condition index, and the accuracy of the J48 classification tree is 80%. This study uses the pavement data of country road in Taoyuan County to build “Country Pavement Performance Index” by entropy. Now, it is a simple way to know the profiler of pavement and detect pavement distress at the same time. This intellegent system can use vediologging module to locate the road image and build a function to let road image import into pavement management system automatically. We can supply the latest information of road to pavement management system.