The perpetual structural pavement design is currently being explored for usage in Canada and worldwide. This thick structural design can provide many potential benefits but it also has associated costs. Cold Canadian winters and warm summers impact pavement performance and make pavement design challenging. This is further complicated by a heavy dependence on trucks to transport imports and exports. Consequently, most Canadian roads are subjected to rapid deterioration due to high fatigue stresses and rapid growth of the traffic loads. The concept of a perpetual pavement design was raised to overcome the limitation of structural capacity of the conventional pavement designs. The concept of perpetual pavement was explained and introduced in this thesis and the benefits behind the perpetual pavement construction were studied. The Ministry of Transportation of Ontario (MTO) and the Centre for Pavement and Transportation Technology (CPATT) joined their efforts in partnership with Natural Sciences and Engineering Research Council (NSERC), Ontario Hot Mix Producers Association (OHMPA), Stantec Consultant, McAsphalt and others to construct three test sections on the Highway 401. The goal was to monitor and evaluate the performance of three different pavement structural designs. Performance evaluation of test section was performed by evaluating the expected ability of pavement section to withstand the traffic loads and climate impact throughout the design life of that pavement section with minimum damage. The minimum damage is expressed as low vertical pressure on top of subgrade, low shear stresses in the surface course and low tensile strain at the bottom of asphalt layers. Perpetual pavement design with Rich Bottom Mix (RBM) layer, perpetual pavement design without RBM and a conventional pavement design were constructed and instrumented with various types of sensors. These are capable of monitoring the tensile strain in asphalt layers, vertical pressure on the subgrade surface, moisture in the subgrade material and the temperature profile in the pavement sections. The test section construction, sensor installation and preliminary modeling are all part of this thesis. Preliminary structural evaluation was performed by analyzing the three designs using a Mechanistic Empirical Pavement Design Guide (MEPDG) model representing the three pavement designs constructed on the Highway 401. In addition, the WESLEA for Windows software was used to validate the long life performance of the perpetual pavement design. Life Cycle Cost Analysis (LCCA) was also performed for the perpetual and conventional pavement designs to evaluate the cost benefits associated with pavement designs for 70 year analysis period. In addition, the perpetual Pavement design philosophy for moderate and low traffic volume roads was also examined in this research. This pavement design involved creating a complete comparison and validation of the benefits of using perpetual asphalt pavements versus the conventional pavements in all road types and traffic categories. Structural evaluation of the pavement sections in moderate and low traffic volume roads was performed. In addition, LCCA was implemented to validate the perpetual and conventional structural pavement designs in moderate and low traffic volume roads.

The perpetual structural pavement design is currently being explored for usage in Canada and worldwide. This thick structural design can provide many potential benefits but it also has associated costs. Cold Canadian winters and warm summers impact pavement performance and make pavement design challenging. This is further complicated by a heavy dependence on trucks to transport imports and exports. Consequently, most Canadian roads are subjected to rapid deterioration due to high fatigue stresses and rapid growth of the traffic loads. The concept of a perpetual pavement design was raised to overcome the limitation of structural capacity of the conventional pavement designs. The concept of perpetual pavement was explained and introduced in this thesis and the benefits behind the perpetual pavement construction were studied. The Ministry of Transportation of Ontario (MTO) and the Centre for Pavement and Transportation Technology (CPATT) joined their efforts in partnership with Natural Sciences and Engineering Research Council (NSERC), Ontario Hot Mix Producers Association (OHMPA), Stantec Consultant, McAsphalt and others to construct three test sections on the Highway 401. The goal was to monitor and evaluate the performance of three different pavement structural designs. Performance evaluation of test section was performed by evaluating the expected ability of pavement section to withstand the traffic loads and climate impact throughout the design life of that pavement section with minimum damage. The minimum damage is expressed as low vertical pressure on top of subgrade, low shear stresses in the surface course and low tensile strain at the bottom of asphalt layers. Perpetual pavement design with Rich Bottom Mix (RBM) layer, perpetual pavement design without RBM and a conventional pavement design were constructed and instrumented with various types of sensors. These are capable of monitoring the tensile strain in asphalt layers, vertical pressure on the subgrade surface, moisture in the subgrade material and the temperature profile in the pavement sections. The test section construction, sensor installation and preliminary modeling are all part of this thesis. Preliminary structural evaluation was performed by analyzing the three designs using a Mechanistic Empirical Pavement Design Guide (MEPDG) model representing the three pavement designs constructed on the Highway 401. In addition, the WESLEA for Windows software was used to validate the long life performance of the perpetual pavement design. Life Cycle Cost Analysis (LCCA) was also performed for the perpetual and conventional pavement designs to evaluate the cost benefits associated with pavement designs for 70 year analysis period. In addition, the perpetual Pavement design philosophy for moderate and low traffic volume roads was also examined in this research. This pavement design involved creating a complete comparison and validation of the benefits of using perpetual asphalt pavements versus the conventional pavements in all road types and traffic categories. Structural evaluation of the pavement sections in moderate and low traffic volume roads was performed. In addition, LCCA was implemented to validate the perpetual and conventional structural pavement designs in moderate and low traffic volume roads.

Nonlinear response history analysis is regarded as the most accurate analysis procedure for estimating seismic response. Approximate analysis procedures are also available for the determination of seismic response and they are preferred over nonlinear response history analysis since much less computational effort is required and good response prediction is achieved by employing rather simple concepts. A generalized pushover analysis procedure is developed in this thesis study as an approximate analysis tool for estimating the inelastic seismic response of structures under earthquake ground excitations. The procedure consists of applying generalized force vectors to the structure in an incremental form until a prescribed target interstory drift demand is achieved. Corresponding generalized force vectors are derived according to this target drift parameter and include the contribution of all modes. Unlike many approximate analysis procedures, response of the structure is directly obtained from generalized pushover analysis results without employing a modal combination rule, eliminating the errors cultivating from these methods. Compared to nonlinear response history analysis, generalized pushover analysis is less demanding in computational effort and its implementation is simpler relative to other approximate analysis procedures. It is observed that the proposed analysis procedure yields results accurately in comparison to the other nonlinear pushover analysis methods. Accordingly it can be suggested as a convenient and sound analysis tool.

Alkali-silica reaction (ASR) and delayed ettringite formation (DEF) are expansive reactions that can lead to the premature deterioration of concrete structures. Both have been implicated in the deterioration of numerous structures around the world, including many transportation structures in Texas. As a result of considerable research advances, ASR and DEF are now avoidable in new construction, but evaluating and managing the existing stock of structures damaged by these mechanisms remains a challenge. While the published guidance for evaluating structures is very effective at diagnosing the presence of ASR and DEF, there remain significant weaknesses with respect to the evaluation of structural safety and serviceability and nondestructive testing (NDT) is a minor component of the evaluation process. The research described in this dissertation involved a wide range of tests on plain and reinforced concrete at multiple scales. This included small cylinders and prisms, larger plain and reinforced concrete specimens in outdoor exposure, full-scale reinforced concrete beams, and core samples from the outdoor exposure specimens and full-scale reinforced concrete beams. Nondestructive test methods were applied at all scales, and the full-scale beams were also tested in four-point flexure to determine the effects of ASR and DEF on flexural strength and serviceability. Severe expansions from ASR and DEF did not reduce the strength of the full-scale beams or result in excessive deflections under live loads, despite significant decreases in the compressive strength and elastic modulus measured from core samples. Most NDT methods were found to be effective at low expansions but had difficulty correlating to larger expansions. Two promising NDT methods have been identified for future research and development, and guidance regarding existing test methods is offered. / text

Orientador: Armando Lopes Moreno Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-09T08:55:46Z (GMT). No. of bitstreams: 1 Oliveira_ClaytonReisde_M.pdf: 8025883 bytes, checksum: ebb8c7495aa749df58c4289566453c26 (MD5) Previous issue date: 2006 / Resumo: Um dos testes mais eficientes para verificar a segurança de uma estrutura concluída é uma prova de carga. Quando existem dúvidas quanto à estabilidade de uma estrutura, devido a fatores, dentre outros, como qualidade dos materiais de construção, utilização ou manutenção inadequada ou até mesmo uma nova utilização da edificação, diferente daquela inicialmente prevista no projeto, uma prova de carga é recomendada. Este trabalho visa apresentar os critérios mais importantes que devem ser considerados em uma prova de carga. Avalia procedimentos das normas brasileira (NBR 9607-1986), americana (ACI 318-2002), australiana (AS 3600-2001) e recomendações espanhola (EHE-1998) e européia (Rilem TBS-2 ¿1984). Destaca aspectos como a obrigatoriedade de uma prova de carga, intensidade do carregamento a ser aplicado, análise dos resultados e critérios de aceitação estipulados pelas referidas normas e recomendações / Abstract: One of the most efficient tests to verify the safety of a structure concluded is a load test. When doubts exist about the stability of a structure, due to factors, among other, as quality of the construction materials, use or inadequate maintenance or even a new use of the construction, different from that initially foreseen in the project, a load test is recommended. This work seeks to present the most important criteria that should be considered in a load test. It evaluates procedures of the Brazilian Code (NBR 96071986), American Code (ACI 318-2002), Australian Code (AS 3600-2001), Spanish Recommendations (EHE-1998) and European Recommendations (Rilem TBS-2 -1984). Aspects as the compulsory nature of a load test, intensity of the applied load, analysis of the results and acceptance criteria stipulated by the referred codes and recommendations are considered. / Mestrado / Estruturas / Mestre em Engenharia Civil

Pavements in Canada that are built on top of frost susceptible soil experience loss of support in early spring as the frozen structure begins thawing. To minimize pavement damage, low- volume roads rely on Spring Load Restrictions (SLR), since building these roads to withstand spring thaw is usually not feasible. However, implementing SLR increases operational costs to commercial transporters and impacts local economies. The Ministry of Transportation Ontario (MTO) is routinely faced with requests from the truck industry to lift restrictions on certain roads, and questioning from municipalities that seek understanding on the needs for SLR in their roads. To help answer these questions, a comprehensive study was performed at 15 Seasonal Load Adjustment (SLA) stations across Ontario. The data collected included Falling Weight Deflectometer (FWD) testing, borehole investigation, climatic data, traffic volumes, and pavement rehabilitation data. A backcalculation using the FWD data estimated pavement structural capacity and remaining service life for each SLA for different dates throughout spring, followed by a life cycle analysis using the rehabilitation data. The SLAs were divided in three groups of similar pavement support conditions based on the service life analysis results. Results indicate that none of Group 1 SLAs need load restrictions, with the calculated remaining service life being greater than 25 years for all test dates. Within Group 2, pavement recovery throughout spring suggests that SLR could extend service life, although generally not necessary for the intended life cycle. Results indicate most SLAs in Group 2 achieving a full life cycle from the last rehabilitation activities for estimates based on early spring parameters, suggesting that these roads were likely designed with spring conditions accounted for. For Group 3, the lack of structural support and low service life values indicate the need for strict load restrictions to avoid excessive damage and maintain serviceability. Pavements with high-quality subgrades, granular structures and non-frost susceptible materials, thick asphalt layers and major rehabilitation activities were found to generally perform well for spring conditions. However, with several site-specific conditions, an overall recommendation for implementation of SLR cannot be generalized based on the pavement structure and subgrade soil type alone. The structural condition and thawing behaviour of individual sites must be thoroughly understood before a decision is made, as investigation might indicate that some roads can withstand full traffic year-round and would not need SLR, while others might need more rigorous restrictions. In addition to the service life analysis, approximately 600 lane km of deflection data was collected using a Multi-Speed Deflectometer in Southern Ontario. Recommendations were made for potential applications of the equipment as a network screening device, able to identify weak road sections in a time and cost-effective manner prior to a detailed investigation using FWD; and for regular monitoring of road conditions at a network level, including the monitoring of seasonal variations. / Thesis / Master of Applied Science (MASc)

Submitted by Lucienne Costa (lucienneferreira@ufcg.edu.br) on 2018-04-13T18:16:49Z No. of bitstreams: 1 MAURO HENRIQUE ALVES NASCIMENTO – DISSERTAÇÃO (PPGECA) 2017.pdf: 22942682 bytes, checksum: d52bbbcac224ea9695c0dd3c9ffc12d1 (MD5) / Made available in DSpace on 2018-04-13T18:16:49Z (GMT). No. of bitstreams: 1 MAURO HENRIQUE ALVES NASCIMENTO – DISSERTAÇÃO (PPGECA) 2017.pdf: 22942682 bytes, checksum: d52bbbcac224ea9695c0dd3c9ffc12d1 (MD5) Previous issue date: 2017-06-09 / Com a finalidade de sanar as degradações do pavimento, devem-se realizar estudos avaliativos das condições estruturais, objetivando identificar as possíveis causas dos defeitos e sobretudo fornecer subsídios, sobre quais medidas corretivas devem ser adotadas para a restauração das condições adequadas e aceitáveis do pavimento. Diante destas circunstâncias, o presente trabalho tem como objetivo identificar as possíveis causas das ocorrências dos defeitos parabólicos observados na superfície dos pavimentos flexíveis das pistas de pouso e decolagem e de taxiamento do Aeroporto Internacional de Natal. Para isso, realizou-se uma avaliação estrutural não destrutiva, por meio do levantamento deflectométrico com o Falling Weight Deflectometer (FWD), o qual foi realizado em toda a extensão das pistas e em diversas faixas de aquisição de dados. Com o FWD obteve-se as bacias de deflexões que possibilitaram por processo de retroanálise, por meio do software BAKFAA 2.0, caracterizar o comportamento resiliente in situ das camadas do pavimento. Com o software ELSYM5 realizou-se a análise empírico-mecanística, para verificar os níveis de tensões cisalhantes atuantes nas diversas profundidades das camadas do pavimento, inclusive na interface de ligação entre as camadas asfálticas. Também foram realizados ensaios laboratoriais de caracterização das propriedades mecânicas, tais como: módulo de resiliência, resistência a tração indireta e o ensaio de Leutner shear Test. Concluiu-se que os defeitos observados na superfície das pistas enquadravam-se na série de defeitos classificados de escorregamento do revestimento asfáltico, ou Slippage, e que os fatores que culminaram na ocorrência destes defeitos relacionam-se com a baixa aderência da interface de ligação e com a incompatibilidade de rigidez entre as camadas adjacentes de mistura asfálticas. / In order to remedy pavement degradation, evaluation studies of the structural conditions should be carried out to identify the possible causes of the defects and, above all, provide information on which corrective measures should be taken to restore adequat and acceptable conditions of the pavement. In view of these circumstances, the present work has the objective of identifying the possible causes of parabolic defects seen in the surface of the flexible pavements of the landing and take - off runways and taxiways of Natal International Airport runway. For this, a non-destructive structural evaluation was carried out by means of the deflectometric survey with the Falling Weight Deflectometer (FWD), which was carried out along the whole length of the tracks and in several ranges of data acquisition. With the FWD, the deflection basins were obtained, which enabled the BAKFAA 2.0 software to characterize the in situ resilient behavior of the pavement layers by means of a retro-analysis process. With the ELSYM5 software, the empirical-mechanistic analysis was performed to verify the levels of shear stresses at different depths of the pavement layers, including the interface between the asphalt layers. Furthermore, laboratory characterization of mechanical properties such as: resilience modulus, tensile strength and Leutner shear test were carried out. It is concluded that the defects observed on the runway surface fit into the series of defects classified as slippage of the asphalt coating, or Slippage, and that the factors that culminated in the occurrence of these defects are related to the low adhesion of the interface and With the incompatibility of stiffness between the adjacent layers of asphalt mixtures.

Master of Science / Department of Civil Engineering / Hani G. Melhem / The objective of this research is to use structure ambient random vibration response to detect damage level and location. The use of ambient vibration is advantageous because excitation is caused by service conditions such as normal vehicle traffic on a highway bridge, train passage on a railroad bridge, or wind loads on a tall building. This eliminates the need to apply a special impact or dynamic load, or interrupt traffic on a bridge in regular service. This research developed an approach in which free vibration of a structure is extracted from the response of this structure to a random excitation in the time domain (acceleration versus time) by averaging out the random component of the response. The result is the free vibration that includes all modes based on the sampling rate on time. Then this free vibration is transferred to the frequency domain using a Fast Fourier Transform (FFT). Variations in frequency response are a function of structural stiffness and member end-conditions. Such variations are used as a measure to identify the change in the structural dynamic properties, and ultimately detect damage. A physical model consisting of a 20 × 20 × 1670 -mm long steel square tube was used to validate this approach. The beam was tested under difference supports conditions varying from a single- to three-span continuous configuration. Random excitation was applied to the beam, and the dynamic response was measured by an accelerometer placed at various locations on the span. A numerical model was constructed in ABAQUS and the dynamic response was obtained from the finite element model subjected to similar excitation as in the physical model. Numerical results were correlated against results from the physical model, and comparison was made between the different span/support configurations. A subsequent step would be to induce damage that simulates loss of stiffness or cracking condition of the beam cross section, and that would be reflected as a change in the frequency and other dynamic properties of the structure. The approach achieved good results for a structure with a limited number of degrees of freedom. Further research is needed for structures with a larger number of degrees of freedom and structures with damage in symmetrical locations relative to the accelerometer position.

A avaliação estrutural é muito importante para os sistemas de gerência de pavimentos, principalmente, para as análises em nível de projeto. Os métodos de dimensionamento de reforço em uso no Brasil, baseado apenas na deflexão recuperável máxima, não exploram todas as potencialidades das avaliações estruturais não destrutivas, pois utilizam expressões empíricas, não associadas diretamente ao comportamento mecanístico do pavimento. Este trabalho tem por objetivo analisar os métodos existentes no Brasil para o dimensionamento de reforço de pavimento flexíveis e compará-los com o dimensionamento mecanístico, baseado nas propriedades mecânicas das camadas do pavimento existente, obtidas mediante retroanálise de avaliações estruturais não destrutivas. Também são analisados fatores que influenciam interpretação dos dados obtidos pelas avaliações estruturais e o processo de retroanálise, como os efeitos da temperatura, as correlações de valores de deflexões obtidas com FDW em valores de deflexões obtidas com Viga Benkelman e as correlações entre os módulos de resiliência das camadas com índices obtidos a partir das deflexões medidas a diferentes distâncias do ponto de aplicação de carga. / Pavement management systems, particularly at project level, are very dependent upon structural evaluation. The pavement rehabilitation design methods used in Brazil are based only on the maximum deflection. They do not explore all the capabilities of non-destructive structural evaluations since they use empirical equations not directly associated to the mechanistic behavior of pavements. This work aims to analyze the Brazilian methods for overlay design and compare them to a mechanistic approach, based on fundamental properties of an elastic-layer system. It is also analyzed factors associated to the interpretation of field data and to the process of back calculation of in situ moduli, such as the effects of pavement temperature during the test, the conversion of deflection values obtained with F.W.D. to deflections values obtained with Benkelman Beam, and the correlations between resilient moduli and indices obtained from deflection values at different distances from the load application point.

A avaliação estrutural é muito importante para os sistemas de gerência de pavimentos, principalmente, para as análises em nível de projeto. Os métodos de dimensionamento de reforço em uso no Brasil, baseado apenas na deflexão recuperável máxima, não exploram todas as potencialidades das avaliações estruturais não destrutivas, pois utilizam expressões empíricas, não associadas diretamente ao comportamento mecanístico do pavimento. Este trabalho tem por objetivo analisar os métodos existentes no Brasil para o dimensionamento de reforço de pavimento flexíveis e compará-los com o dimensionamento mecanístico, baseado nas propriedades mecânicas das camadas do pavimento existente, obtidas mediante retroanálise de avaliações estruturais não destrutivas. Também são analisados fatores que influenciam interpretação dos dados obtidos pelas avaliações estruturais e o processo de retroanálise, como os efeitos da temperatura, as correlações de valores de deflexões obtidas com FDW em valores de deflexões obtidas com Viga Benkelman e as correlações entre os módulos de resiliência das camadas com índices obtidos a partir das deflexões medidas a diferentes distâncias do ponto de aplicação de carga. / Pavement management systems, particularly at project level, are very dependent upon structural evaluation. The pavement rehabilitation design methods used in Brazil are based only on the maximum deflection. They do not explore all the capabilities of non-destructive structural evaluations since they use empirical equations not directly associated to the mechanistic behavior of pavements. This work aims to analyze the Brazilian methods for overlay design and compare them to a mechanistic approach, based on fundamental properties of an elastic-layer system. It is also analyzed factors associated to the interpretation of field data and to the process of back calculation of in situ moduli, such as the effects of pavement temperature during the test, the conversion of deflection values obtained with F.W.D. to deflections values obtained with Benkelman Beam, and the correlations between resilient moduli and indices obtained from deflection values at different distances from the load application point.