The aim of this research is to assess the material properties of concrete like modulus of elasticity, compressive strength, and Poisson’s ratio using various nondestructive Testing (NDT) methods like Ultrasonic Pulse Velocity (UPV) and Rebound Hammer (RH). Assessment of material properties of concrete is very important as they are used for structural design process. Various NDT methods are applied to ensure the quality of concrete specimens but they can also be used to find material properties. UPV is a NDT method which is used to test the internal condition of the concrete specimen. RH is a surface hardness testing method and can be used to test the homogeneity of the specimen. For this study, several batches of concrete samples with three different design strengths of 6000 psi, 8000 psi, and 12000 psi were casted. Modulus of elasticity and Poisson’s ratio were calculated from UPV P-wave and S-wave velocities. A Nomogram was developed by combining the longitudinal ultrasonic pulse velocities, rebound numbers, and compressive strengths measured from UPV, RH, and compressive strength tests respectively. This combined NDT correlation curve (Nomogram) can be used to estimate compressive strength of concrete if UPV and rebound values are known. The accuracy of these NDT methods were determined by comparing estimated strength to the actual strength. Furthermore, the effect of moisture content on UPV and rebound values was reviewed and also studied dynamic modulus of elasticity and its relation with static modulus of elasticity of the concrete was investigated for better understanding.

Non-destructive testing is of great value in cases where a structure's future is investigated to find out what the best measure is. It is not always the best solution to demolish and build new. Many structures can be repaired and function several more years. In this thesis the main goal is to investigate some different non-destructive techniques and learn more about difficulties and strengths. The test subjects will be a cast T-beam in a laboratory environment as well as a case study of a railway bridge in Abisko.   The different testing equipment being used in this thesis is a covermeter, a rebound hammer and ultrasonic pulse velocity. For both the T-beam and the bridge the results are overall very good. The covermeter is proven to be both easy to use and very reliable and the ultrasonic pulse velocity was more to learn about and more difficult but is giving very good results as well.   Conclusions after the thesis project is that it requires a lot of experience of the user and time to make non-destructive testing useful and competitive in the society. Getting all the pieces together it is a powerful tool that hopefully is a sustainable asset in the future, regarding both economic and environmental issues.

The diploma thesis deals with non-destructive testing of concrete as well as with the relationship between determined parameters and the compressive strength of concrete. The thesis is mainly focused on the ultrasonic pulse velocity method and the rebound hammer test. The experimental part of the thesis describes non-destructive tests performed on concrete blocks. The compressive strength was tested on the drill cores taken from the concrete blocks. The aim of this thesis is to find regression models of the relationship between the compressive strength and non-destructive parameters, and the subsequent analysis of the results.

This thesis deals with the rebound hammer method as a tool for approximation of the time limit for handling the concrete. The theoretical part is focused on three fields of knowledge - rebound hammer test, production of precast concrete components and statistical data analysis. The following practical part deals with the design of two single-parameter linear functions for two types of rebound hammer testers - SilverSchmidt L and SchmidtOriginal N. Statistical data processing is completed by the analysis of influential points by using the Cook’s distance. The resulting statistical models are compared with commonly used relationships.

No description available.

No description available.

There has been increasing interest in evaluating the performance of existing reinforced concrete (RC) bridges just after natural disasters or man-made events especially when the defects are invisible, or in quantifying the improvement after rehabilitations. In order to obtain an accurate assessment of the reliability of a RC bridge, it is critical to incorporate information about its current structural properties, which reflects the possible aging and deterioration. This dissertation proposes to develop an adaptive reliability analysis of RC bridges incorporating the damage detection information obtained from nondestructive testing (NDT). In this study, seismic fragility is used to describe the reliability of a structure withstanding future seismic demand. It is defined as the conditional probability that a seismic demand quantity attains or exceeds a specified capacity level for given values of earthquake intensity. The dissertation first develops a probabilistic capacity model for RC columns and the capacity model can be used when the flexural stiffness decays nonuniformly over a column height. Then, a general methodology to construct probabilistic seismic demand models for RC highway bridges with one single-column bent is presented. Next, a combination of global and local NDT methods is proposed to identify in-place structural properties. The global NDT uses the dynamic responses of a structure to assess its global/equivalent structural properties and detect potential damage locations. The local NDT uses local measurements to identify the local characteristics of the structure. Measurement and modeling errors are considered in the application of the NDT methods and the analysis of the NDT data. Then, the information obtained from NDT is used in the probabilistic capacity and demand models to estimate the seismic fragility of the bridge. As an illustration, the proposed probabilistic framework is applied to a reinforced concrete bridge with a one-column bent. The result of the illustration shows that the proposed framework can successfully provide the up-to-date structural properties and accurate fragility estimates.

A RS471/BR153 é uma importante rodovia de integração, pois atravessa o estado do RS diagonalmente (Noroeste – Sudeste). O trecho estudado nesta dissertação localiza-se entre os municípios de Herveiras e Vera Cruz, coincidente com descida do planalto até a região central do estado. Durante o detalhamento do projeto e na construção da obra foram encontrados diversos problemas geotécnicos, os quais são sucintamente descritos. O texto apresenta as condicionantes geotécnicas de três subtrechos: (a) planalto, composto de rochas ácidas de origem vulcânica e grau de fraturamento muito alto; (b) descida da serra, composto pelos derrames da formação Serra Geral (brechas ácidas e basálticas e derrames basálticos) e (c) planície, com a presença de rochas sedimentares e materiais coluvionares. Além disto, há uma região especial onde o traçado atravessa uma sela topográfica coincidente com uma falha regional, com cortes de cerca de 60 m de altura através de rochas ácidas, básicas e brechas vulcânicas. A dissertação apresenta estudos dos processos de quedas de blocos rochosos que têm ocorrido nos cortes da rodovia. Foi utilizado um procedimento que correlaciona as leituras obtidas com o martelo Schmidt (Esclerômetro) e o coeficiente de restituição normal (RN) das rochas em diversos locais. Utilizando estes dados experimentais, foram executadas simulações de queda de blocos em quatro seções transversais bastante distintas com o uso do programa RocFall. Para cada seção foram simulados cinco cenários: (a) a existência de alargamentos para construção de áreas de retenção de blocos, (b) inexistência destas áreas, (c) a existência de preenchimento de uma ou várias banquetas existentes nos taludes de corte, e (d) o abatimento da seção com eliminação das banquetas. Foram também simulados quatro tipos de elementos de proteção: barreiras de baixa altura em concreto, camadas de areia fofa, barreiras metálicas flexíveis e proteção superficial dos taludes. A existência de áreas de retenção de blocos mostrou ser uma ótima medida, com frequências de invasão de pista geralmente abaixo de 1%, podendo chegar a 6,5% em condições de grande acúmulo de material. O melhor desempenho foi obtido pela instalação de camadas de areia fofa, obtendo-se todas as frequências abaixo de 2%. O uso de barreiras rígidas de 81 cm de altura teve um bom desempenho para taludes de baixa altura, chegando a detenções de até 25% dos blocos em trajetória de invasão. As barreiras flexíveis e proteções superficiais geraram resultados satisfatórios, mas que podem ser melhorados com outras modulações e dimensões. / The RS471/BR153 is an important road of integration, that cross RS state diagonally (northwest - southeast). The segment studied on this dissertation is located between the towns of Vera Cruz and Herveiras, coincident with the descent way from the plateau to the central state region. During the design and during the road construction several geotechnical problems were faced, which are briefly described. The text presents the geotechnical constraints of 3 segments: (a) plateau, composed of acid rocks of volcanic origin and very high degree of fracturing, (b) hills of the mountain, made up of volcanic rocks of Serra Geral formation (acid and basaltic breccias, basaltic flows) and (c) the plain, with the presence of sedimentary rocks and colluvial materials. There is also a special region where the road crosses a topographic saddle which it coincides with a regional fault, with cuts of about 60 m high through acid and basic rocks and volcanic breccia. The dissertation presents studies of rock falls that have occurred in the road cuts. A procedure that correlates the readings obtained with the Schmidt hammer (rebound hammer) and the normal coefficient of restitution (RN) of the rocks was carried out for measures taken at several locations. With these experimental data, simulations of falling boulders in four very different cross sections were done using the program RocFall. For each section five situations were simulated: (a) enlargements for the construction of rockfall catchment areas (b) the absence of these areas, (c) the existence of accumulation in the benchs of the cuts, and (d) the reduction of the section with bench removal. Four types of elements of protection were tested: concrete low barriers, layers of sand, flexible metal barriers and slope surface protection. The existence of rockfall catchment areas was shown to be a very good measure with frequencies of track invasion usually below 1% reaching 6.5% on conditions of large material accumulation. The best performance was obtained by the installation of sand layers, with all frequencies below 2%. The use of rigid barriers of 81 cm high had a good performance for low-slope heights, reaching up to 25% block retention. The use of flexible barriers and surface protections also had a good performance. / La RS471/BR153 es una importante carretera de integración, atraviesa el estado de RS diagonalmente (Noroeste-Sureste). El tramo estudiado en esta disertación se localiza entre los municipios de Herveiras y Vera Cruz, y coincide con el descenso desde el altiplano hasta la región central del estado. Durante las etapas de detalle y construcción de la obra fueron encontrados diversos problemas geotécnicos que son brevemente descritos. El texto presenta los condicionantes geotécnicos de tres subtramos: (a) altiplano, compuesto por rocas ácidas de origen volcánico y grado de fracturamiento muy alto; (b) descenso de la sierra, compuesto por los derrames de la formación Serra Geral (brechas ácidas y basálticas e derrames basálticos) y (c) planicie, con rocas sedimentarias y materiales coluviales. Además, hay una región donde el trazado atraviesa una “silla” topográfica que coincide con una falla regional, con cortes de aproximadamente 60 m de altura a través de rocas ácidas, básicas y brechas volcánicas. La disertación presenta estudios de procesos de caídas de rocas que han ocurrido en algunos cortes. Fue utilizado un procedimiento que correlaciona las lecturas obtenidas con el martillo Schmidt (Esclerómetro) y el coeficiente de restitución normal (RN) de las rocas en diferentes lugares. Con estos datos experimentales, fueron ejecutadas simulaciones de caídas de rocas en cuatro secciones transversales bastante distintas usando el programa RocFall. En cada sección fueron simulados cinco escenarios: (a) existencia de sobreanchos para la construcción de áreas de retención de rocas, (b) inexistencia de estas áreas, (c) existencia de relleno en una o más gradas existentes en los taludes de corte, y (d) diminución de la pendiente de los taludes y eliminación de las gradas. También fueron simulados cuatro tipos de elementos de protección: barreras de baja altura en concreto, capas de arena suelta, barreras metálicas flexibles y protección superficial de los taludes. La existencia de áreas de retención de rocas mostro ser una excelente medida, con frecuencias de invasión de pista generalmente inferiores a 1%, pudiendo llegar a 6,5% en condiciones de gran acumulación de material. El mejor desempeño fue obtenido con la instalación de capas de arena suelta, con todas las frecuencias por debajo de 2%. El uso de barreras rígidas de 81 cm de altura tuvo un buen desempeño para taludes de baja altura, llegando a detenciones de hasta 25% de los bloques en trayectoria de invasión. Las barreras flexibles y protecciones superficiales generaron resultados satisfactorios, que podrían ser mejorados con otras modulaciones y dimensiones.

A RS471/BR153 é uma importante rodovia de integração, pois atravessa o estado do RS diagonalmente (Noroeste – Sudeste). O trecho estudado nesta dissertação localiza-se entre os municípios de Herveiras e Vera Cruz, coincidente com descida do planalto até a região central do estado. Durante o detalhamento do projeto e na construção da obra foram encontrados diversos problemas geotécnicos, os quais são sucintamente descritos. O texto apresenta as condicionantes geotécnicas de três subtrechos: (a) planalto, composto de rochas ácidas de origem vulcânica e grau de fraturamento muito alto; (b) descida da serra, composto pelos derrames da formação Serra Geral (brechas ácidas e basálticas e derrames basálticos) e (c) planície, com a presença de rochas sedimentares e materiais coluvionares. Além disto, há uma região especial onde o traçado atravessa uma sela topográfica coincidente com uma falha regional, com cortes de cerca de 60 m de altura através de rochas ácidas, básicas e brechas vulcânicas. A dissertação apresenta estudos dos processos de quedas de blocos rochosos que têm ocorrido nos cortes da rodovia. Foi utilizado um procedimento que correlaciona as leituras obtidas com o martelo Schmidt (Esclerômetro) e o coeficiente de restituição normal (RN) das rochas em diversos locais. Utilizando estes dados experimentais, foram executadas simulações de queda de blocos em quatro seções transversais bastante distintas com o uso do programa RocFall. Para cada seção foram simulados cinco cenários: (a) a existência de alargamentos para construção de áreas de retenção de blocos, (b) inexistência destas áreas, (c) a existência de preenchimento de uma ou várias banquetas existentes nos taludes de corte, e (d) o abatimento da seção com eliminação das banquetas. Foram também simulados quatro tipos de elementos de proteção: barreiras de baixa altura em concreto, camadas de areia fofa, barreiras metálicas flexíveis e proteção superficial dos taludes. A existência de áreas de retenção de blocos mostrou ser uma ótima medida, com frequências de invasão de pista geralmente abaixo de 1%, podendo chegar a 6,5% em condições de grande acúmulo de material. O melhor desempenho foi obtido pela instalação de camadas de areia fofa, obtendo-se todas as frequências abaixo de 2%. O uso de barreiras rígidas de 81 cm de altura teve um bom desempenho para taludes de baixa altura, chegando a detenções de até 25% dos blocos em trajetória de invasão. As barreiras flexíveis e proteções superficiais geraram resultados satisfatórios, mas que podem ser melhorados com outras modulações e dimensões. / The RS471/BR153 is an important road of integration, that cross RS state diagonally (northwest - southeast). The segment studied on this dissertation is located between the towns of Vera Cruz and Herveiras, coincident with the descent way from the plateau to the central state region. During the design and during the road construction several geotechnical problems were faced, which are briefly described. The text presents the geotechnical constraints of 3 segments: (a) plateau, composed of acid rocks of volcanic origin and very high degree of fracturing, (b) hills of the mountain, made up of volcanic rocks of Serra Geral formation (acid and basaltic breccias, basaltic flows) and (c) the plain, with the presence of sedimentary rocks and colluvial materials. There is also a special region where the road crosses a topographic saddle which it coincides with a regional fault, with cuts of about 60 m high through acid and basic rocks and volcanic breccia. The dissertation presents studies of rock falls that have occurred in the road cuts. A procedure that correlates the readings obtained with the Schmidt hammer (rebound hammer) and the normal coefficient of restitution (RN) of the rocks was carried out for measures taken at several locations. With these experimental data, simulations of falling boulders in four very different cross sections were done using the program RocFall. For each section five situations were simulated: (a) enlargements for the construction of rockfall catchment areas (b) the absence of these areas, (c) the existence of accumulation in the benchs of the cuts, and (d) the reduction of the section with bench removal. Four types of elements of protection were tested: concrete low barriers, layers of sand, flexible metal barriers and slope surface protection. The existence of rockfall catchment areas was shown to be a very good measure with frequencies of track invasion usually below 1% reaching 6.5% on conditions of large material accumulation. The best performance was obtained by the installation of sand layers, with all frequencies below 2%. The use of rigid barriers of 81 cm high had a good performance for low-slope heights, reaching up to 25% block retention. The use of flexible barriers and surface protections also had a good performance. / La RS471/BR153 es una importante carretera de integración, atraviesa el estado de RS diagonalmente (Noroeste-Sureste). El tramo estudiado en esta disertación se localiza entre los municipios de Herveiras y Vera Cruz, y coincide con el descenso desde el altiplano hasta la región central del estado. Durante las etapas de detalle y construcción de la obra fueron encontrados diversos problemas geotécnicos que son brevemente descritos. El texto presenta los condicionantes geotécnicos de tres subtramos: (a) altiplano, compuesto por rocas ácidas de origen volcánico y grado de fracturamiento muy alto; (b) descenso de la sierra, compuesto por los derrames de la formación Serra Geral (brechas ácidas y basálticas e derrames basálticos) y (c) planicie, con rocas sedimentarias y materiales coluviales. Además, hay una región donde el trazado atraviesa una “silla” topográfica que coincide con una falla regional, con cortes de aproximadamente 60 m de altura a través de rocas ácidas, básicas y brechas volcánicas. La disertación presenta estudios de procesos de caídas de rocas que han ocurrido en algunos cortes. Fue utilizado un procedimiento que correlaciona las lecturas obtenidas con el martillo Schmidt (Esclerómetro) y el coeficiente de restitución normal (RN) de las rocas en diferentes lugares. Con estos datos experimentales, fueron ejecutadas simulaciones de caídas de rocas en cuatro secciones transversales bastante distintas usando el programa RocFall. En cada sección fueron simulados cinco escenarios: (a) existencia de sobreanchos para la construcción de áreas de retención de rocas, (b) inexistencia de estas áreas, (c) existencia de relleno en una o más gradas existentes en los taludes de corte, y (d) diminución de la pendiente de los taludes y eliminación de las gradas. También fueron simulados cuatro tipos de elementos de protección: barreras de baja altura en concreto, capas de arena suelta, barreras metálicas flexibles y protección superficial de los taludes. La existencia de áreas de retención de rocas mostro ser una excelente medida, con frecuencias de invasión de pista generalmente inferiores a 1%, pudiendo llegar a 6,5% en condiciones de gran acumulación de material. El mejor desempeño fue obtenido con la instalación de capas de arena suelta, con todas las frecuencias por debajo de 2%. El uso de barreras rígidas de 81 cm de altura tuvo un buen desempeño para taludes de baja altura, llegando a detenciones de hasta 25% de los bloques en trayectoria de invasión. Las barreras flexibles y protecciones superficiales generaron resultados satisfactorios, que podrían ser mejorados con otras modulaciones y dimensiones.

Pour évaluer la résistance mécanique du béton dans un ouvrage existant, la méthodologie courante combine des mesures non destructives (CND) comme le rebond ou/et la vitesse des ondes ultrasoniques avec la technique destructive (carottes) afin de produire une relation‘‘modèle de conversion” entre la résistance mécanique et les mesures CND. Le modèle de conversion est utilisé pour estimer la valeur locale de résistance mécanique à chaque emplacement de test en utilisant la valeur CND correspondante. Ensuite, on calcule les estimations de la résistance moyenne et/ou de l’écart-type de la résistance (variabilité de la résistance du béton). Cependant, la fiabilité d’estimation est toujours discutable en raison des incertitudes associées à l’évaluation de la résistance basée sur les mesures CND. Pour améliorer la fiabilité, les incertitudes doivent être réduites en spécifiant et en contrôlant leurs facteurs d’influence. Par conséquent, l’objectif de cette thèse est d’analyser la méthodologie d’évaluation courante afin de fournir des recommandations pratiques qui peuvent améliorer la fiabilité de l’évaluation de la résistance in-situ du béton dans les ouvrages existantes par des tests non destructifs et des carottes.Pour ce but, un simulateur a été construit afin d’analyser les effets des facteurs les plus influents en utilisant une vaste campagne de données provenant de sources différentes (études in situ ou en laboratoire et données synthétiques générées). La première contribution de ce travail est le développement d’une nouvelle approche d’identification du modèle ‘‘bi-objectif” qui peut efficacement capturer la variabilité de la résistance mécanique en plus de la moyenne. Après avoir étudié l’effet du mode de sélection des emplacements pour les carottes, une méthode a été proposée pour sélectionner ces emplacements en fonction des mesures CND ‘‘sélection conditionnelle” qui améliore la qualité de l’évaluation sans coût supplémentaire. Une dernière innovation est l’établissement de courbes de risque qui quantifient la relation entre le nombre de carottes et la précision de l’estimation. Enfin, des recommandations ont été formulées afin de fournir des estimations plus fiables. / To assess concrete strength in an existing structure, the current methodology combines nondestructive measurements (NDT) like rebound hammer or/and pulse velocity with destructive technique (cores) in order to implement a relationship ‘‘conversion model” between the compressive strength and NDT measurements. The conversion model is used to estimate the local strength value at each test location using the corresponding NDT value.Then the estimated mean strength and/or estimated strength standard deviation (concrete strength variability) values are calculated. However, the reliability of these estimated values isalways a questionable issue because of the uncertainties associated with the strength assessment based upon NDT measurements. To improve the reliability, the uncertainties must be reduced by specifying and controlling their influencing factors. Therefore, the objective of this thesis is to analyze the current assessment methodology in order to provide practical recommendations that can improve the reliability of assessing the in-situ strength in existing concrete structures by nondestructive tests and cores.To this end, a simulator was built in order to analyze the effects of the most influencing factors using a large campaign of datasets from different sources (in-situ or laboratory studies,and generated synthetic data).The first contribution of this work is the development of a new model identification approach“bi-objective” that can efficiently capture the strength variability in addition to the mean strength. After studying the effect of the way of selection the core locations, a method was proposed to select these locations depending on the NDT measurements “conditional selection” that improves the quality of assessment without additional cost. A third innovation was the development of a procedure to identify the relation between the number of cores and the accuracy of the estimation. Finally recommendations were derived in order to providemore reliable estimated values.