The study assessed the knowledge structure of Grade 11 physics students and their instructors using Pathfinder networks. Instructors’ structural knowledge was averaged to create a referent pathfinder network. Each student’s pathfinder network was compared with the referent pathfinder network in order to identify misconceptions. These misconceptions served as the basis for remedial instruction. The study was conducted in six sections of Grade 11. Three different types of remedial instruction based on three different chapters from the Grade 11 physics textbook were given to the students at three separate stages. In the first section, students were shown their own and referent pathfinder networks as an intervention during the first stage. The students were asked to reflect on the similarities and differences between them. The researcher gave written concept-oriented exercises based on the differences at the second stage, and multimedia concept-oriented instruction based on the differences was given to the students at the third stage. The order of instruction was counterbalanced in all the six sections. After each stage, students’ pathfinder networks were reassessed and the similarities between students’ and the referent pathfinder networks were calculated to measure the effect of a particular intervention. The study tried to determine which type of remedial instruction given to students best improved the knowledge structure of the students in the domain of physics. Results revealed that the similarity indices around the treatment concepts in the pathfinder networks of the students increased the most from pre- to post-intervention phase because of their reflections, followed by multimedia concept-oriented instruction and written concept-oriented exercises. Most likely, the major reason for this change was the interventions around the treatment concepts by the researcher at three different stages which stimulated and probably changed some of students’ misconceptions. To address the issue of validity, the similarity indices of control concepts in the students’ pathfinder networks were also checked for improvement. The result shows that there is no appreciable improvement in control concepts as there was no intervention around those concepts. Findings support the use of structural assessment of knowledge with pathfinder scaling technique to check the effectiveness of a classroom instruction.

A combined experimental and analytical program was conducted to investigate the effects of Alkali-Silica Reaction (ASR) and Delayed Ettringite Formation (DEF) on D-regions in reinforced concrete (RC) bridge bents. Four large-scale RC specimens, which represent cantilever and straddle bents in Texas bridges in each specimen, were constructed. The first specimen represented the unexposed control specimen, while the other three were conditioned in the field with supplemental watering to promote ASR/DEF and served as the exposed specimens. The control and two exposed specimens with various levels of ASR/DEF, after eight months and two years of field conditioning, were load tested to failure. The last specimen remains in field with additional exposure to promote ASR/DEF and will be load tested in future studies. The width and length of preload-induced cracks and developing cracks that initiated in the exposed specimens and grew over time, indicating concrete expansion due to ASR/DEF mechanisms, were measured. Petrographic analysis results of concrete cores extracted from the exposed specimens after their load testing confirmed the formation of ASR gel and minimum accumulation of ettringite. The structural testing results showed that the failure mechanism in all three tested specimens was due to a brittle shear failure in the beam-column joint. However, slightly greater stiffness, strength, and ductility were observed in the exposed specimens as a result of the activation of the reinforcing steel in the specimens due to the expansion of the concrete primarily from ASR, which effectively prestressed and confined the core concrete. Sectional analysis and Strut-and-Tie Modeling (STM) of the experimental specimens were applied. Three-dimensional nonlinear Finite Element Analyses (FEA) were also conducted to numerically simulate the overall structural performance, internal response, and out-of-plane behavior of the experimental specimens. The effects of varying constitutive relations of the concrete in tension on models of the specimens were compared with the measured experimental response. A method to mimic ASR/DEF effects on exposed specimens was proposed and incorporated into the FEA approach. As a result, forces that prestress and confine the core concrete were effectively applied through the reinforcing steel prior to subsequent structural loading. The three-dimensional FEA approach was able to simulate the out-of-plane behavior of the beam-column joint and the proposed method yielded comparable results with the measured overall and internal behavior of specimens.

The study assessed the knowledge structure of Grade 11 physics students and their instructors using Pathfinder networks. Instructors’ structural knowledge was averaged to create a referent pathfinder network. Each student’s pathfinder network was compared with the referent pathfinder network in order to identify misconceptions. These misconceptions served as the basis for remedial instruction. The study was conducted in six sections of Grade 11. Three different types of remedial instruction based on three different chapters from the Grade 11 physics textbook were given to the students at three separate stages. In the first section, students were shown their own and referent pathfinder networks as an intervention during the first stage. The students were asked to reflect on the similarities and differences between them. The researcher gave written concept-oriented exercises based on the differences at the second stage, and multimedia concept-oriented instruction based on the differences was given to the students at the third stage. The order of instruction was counterbalanced in all the six sections. After each stage, students’ pathfinder networks were reassessed and the similarities between students’ and the referent pathfinder networks were calculated to measure the effect of a particular intervention. The study tried to determine which type of remedial instruction given to students best improved the knowledge structure of the students in the domain of physics. Results revealed that the similarity indices around the treatment concepts in the pathfinder networks of the students increased the most from pre- to post-intervention phase because of their reflections, followed by multimedia concept-oriented instruction and written concept-oriented exercises. Most likely, the major reason for this change was the interventions around the treatment concepts by the researcher at three different stages which stimulated and probably changed some of students’ misconceptions. To address the issue of validity, the similarity indices of control concepts in the students’ pathfinder networks were also checked for improvement. The result shows that there is no appreciable improvement in control concepts as there was no intervention around those concepts. Findings support the use of structural assessment of knowledge with pathfinder scaling technique to check the effectiveness of a classroom instruction.

The study assessed the knowledge structure of Grade 11 physics students and their instructors using Pathfinder networks. Instructors’ structural knowledge was averaged to create a referent pathfinder network. Each student’s pathfinder network was compared with the referent pathfinder network in order to identify misconceptions. These misconceptions served as the basis for remedial instruction. The study was conducted in six sections of Grade 11. Three different types of remedial instruction based on three different chapters from the Grade 11 physics textbook were given to the students at three separate stages. In the first section, students were shown their own and referent pathfinder networks as an intervention during the first stage. The students were asked to reflect on the similarities and differences between them. The researcher gave written concept-oriented exercises based on the differences at the second stage, and multimedia concept-oriented instruction based on the differences was given to the students at the third stage. The order of instruction was counterbalanced in all the six sections. After each stage, students’ pathfinder networks were reassessed and the similarities between students’ and the referent pathfinder networks were calculated to measure the effect of a particular intervention. The study tried to determine which type of remedial instruction given to students best improved the knowledge structure of the students in the domain of physics. Results revealed that the similarity indices around the treatment concepts in the pathfinder networks of the students increased the most from pre- to post-intervention phase because of their reflections, followed by multimedia concept-oriented instruction and written concept-oriented exercises. Most likely, the major reason for this change was the interventions around the treatment concepts by the researcher at three different stages which stimulated and probably changed some of students’ misconceptions. To address the issue of validity, the similarity indices of control concepts in the students’ pathfinder networks were also checked for improvement. The result shows that there is no appreciable improvement in control concepts as there was no intervention around those concepts. Findings support the use of structural assessment of knowledge with pathfinder scaling technique to check the effectiveness of a classroom instruction.

Yes / Structural walls of old historical structures are either blind or have openings for functional requirements. It is well known that in and out of plane responses of structural walls are affected by the size, locations, and arrangements of such openings. The purpose of this investigation is to study the window opening effects on static and seismic behaviors of historical masonry old mosques. Fatih Mosque, which was converted from a church, constructed in 914 in Trabzon, Turkey, is selected for this purpose. The mosque is being restored. Structural exterior walls of the mosque were made using stone and mortar materials. When the plaster on the walls was removed during the restoration, 12 window openings were found as blind on the exterior structural walls of the mosque. Within the scope of restoration works, it is aimed to open such blind windows. In order to investigate the effects of the window openings on the structural behavior of the mosque, 3D solid and finite elements models of the mosque with and without window openings are initially developed. The experimental dynamic characteristics such as frequency, damping ratio, and mode shapes of the current situation of the mosque, where some windows openings are blind, are determined using Ambient Vibration Testing. Then, the finite element model of the current situation of the mosque is updated using the experimental dynamic characteristics. The static and seismic time history analyses of the updated finite element model with and without window openings are carried out. Structural behaviors of the mosque with and without window openings are compared considering displacement and stress propagations.

[pt] A avaliação estrutural de dutos com defeitos de corrosão vem sendo estudada desde o final da década de 60. A partir dos conceitos da Mecânica da Fratura, foram elaboradas expressões semi-empíricas que permitiram estimar a pressão de ruptura de defeitos de corrosão. Desde então, essas expressões foram sendo ajustadas e aprimoradas por testes de ensaios destrutivos e análise de elementos finitos. Os principais métodos desenvolvidos são o ASME B31G, 085dL, Effective Area, DNV RP F-101 (defeitos isolados) e DNV RP F-101 (defeitos complexos). Esta tese foi elaborada utilizando alguns dos ensaios programados para o projeto Produt 600536, e parte dos seus resultados foi aproveitada neste projeto. Para o trabalho de tese, foram utilizados cinco espécimes tubulares de aço API 5L X46, com 3,0 m de comprimento aproximado, diâmetro nominal de 457,2 mm e espessura nominal de 6,35 mm. Estes espécimes continham defeitos reais de corrosão interna, do tipo longo, localizados na geratriz inferior, e foram retirados do oleoduto Orbel I, pertencente à Petrobras, durante a sua obra de reabilitação, em 2001. Os defeitos de corrosão foram mapeados com medições manuais por ultra-som espaçadas em 20 mm e com medições mecanizadas CSCAN espaçadas em 5mm. Para cada espécime, foram realizados ensaios de tração em 4 corpos de prova, sendo 2 corpos retirados transversalmente e 2 longitudinalmente. Estes espécimes foram instrumentados com extensômetros de resistência elétrica e pressurizados até a ruptura. Para cada espécime, foram levantados diversos perfis de corrosão em função do comprimento estabelecido para o defeito e do tipo de medição (manual ou mecanizada). A pressão de ruptura foi estimada pelas equações dos métodos ASME B31G, 085dL, Effective Area, DNV RP F-101 (defeitos isolados) e DNV RP F-101 (defeitos complexos), utilizando planilha Excel e/ou os programas computacionais RSTRENG e DNV RP F-101. Os valores de pressão de ruptura estimados para os espécimes, utilizando os métodos acima relacionados, foram comparados com as pressões de ruptura reais, obtidas nos ensaios de pressão. Os resultados confirmaram o conservadorismo embutido no método ASME B31G e comprovaram que os métodos Effective Area e DNV RP-F101 (complexo), que utilizam o perfil de corrosão, apresentam resultados melhores que os métodos ASME B31G e 085dL e podem ser considerados uma boa ferramenta para avaliar defeitos de corrosão, considerando somente carregamento de pressão interna. / [en] Structural assessment of pipelines with corrosion defects has been studied since the late 1960s. From the principles of fracture mechanics, semi-emprical mathematical expressions have been developed for predicting burst pressure of corroded pipes. Subsequently, these expressions have been modified and calibrated based on the results from finite element analyses and laboratory burst tests. The main methods are ASME B31G, Modified B31G (version 0.85 dL), Effective Area and DNV RP-F101 for single and complex shaped defects. This thesis was done utilizing some laboratory tests from Produt 600536 Project. For this study, five specimens with 3.0 meters each were removed from Petrobras pipeline (Orbel I), during its rehabilitation. The pipe material was API 5L X46, 18 diameter and 0.25 wall thickness. These specimens had real internal corrosion with very long defect length, at the 6:00 o`clock position. The corrosion defects were mapped by manual ultrasound, at 20 mm intervals, and mecanized ultrasonic measurements CSCAN at 5 mm intervals. For each pipe, the yield strength and ultimate strength were determined by tension tests of 4 specimens, 2 removed from transverse and 2 longitudinal. Every pipe specimen was monitored by strain gages and pressurized up to the point of rupture. For each specimen different profiles were determined depending on the length defined for the defect and for the intervals of measurements. The burst pressure was predicted by the following methods: ASME B31G, Modified B31G (version 0.85 dL), Effective Area and DNV RP-F101 for single and complex defects. These predicted rupture pressures were compared with the real burst pressures. The results confirmed the conservatism of the ASME B31G method and demonstrated that the Effective Area and DNV RP-F101 for complex shaped defects methods can be considered good for evaluating longitudinal corrosion defects, considering only internal pressure load.

[pt] A redução de espessura de parede causada por corrosão é um dos defeitos que mais afetam a integridade dos dutos. Estes defeitos podem ocorrer no metal base, nas soldas longitudinais ou circunferenciais, bem como nas zonas afetadas pelo calor. Os métodos de avaliação da resistência remanescente introduzem ressalvas ou proíbem o tratamento de defeitos de corrosão coincidentes com as juntas soldadas. No presente trabalho foram avaliados os níveis de segurança dos métodos usuais de avaliação da resistência de dutos com defeitos introduzidos na região da solda longitudinal de tubos soldados por arco submerso. Os tubos testados eram de aço C-Mn fabricados na década de 60 e foram retirados de operação após uma campanha superior a 30 anos. Com estes tubos foram fabricados 5 espécimes, cada qual com 1 defeito externo produzido por eletro-erosão, sendo posteriormente submetidos a testes de pressão monitorados. Foram realizados ensaios de tração, ensaios de impacto Charpy e ensaios de dobramento, para determinação das propriedades mecânicas do metal de base, do metal de solda e da zona termicamente afetada (ZTA). Foram realizados também ensaios metalográficos do metal de base e do metal de solda, análise química do metal de base e do metal de solda e medição das tensões residuais no metal de solda. A aplicação dos métodos de nível 1 (ASME B31G, 085dL, RPA, DNV isolado e PCORRC) resultou em pressões previstas inferiores às pressões reais de ruptura para defeitos de formato esférico. Para defeitos de seção retangular a aplicação dos métodos de nível 1 resultou em pressões superiores às pressões reais. A aplicação dos métodos de nível 2 (Effective Area e DNV geometria complexa) resultou em pressões previstas superiores às pressões reais de ruptura para defeitos de formato esférico e de seção retangular. As análises das fraturas indicaram que não ocorreu falha por deficiência de tenacidade em nenhum espécime. A corrosão alveolar leve pré-existente na superfície interna dos espécimes foi apontada como causa mais provável das pressões previstas superiores às pressões reais de ruptura. / [en] One of the most important issues that affects pipeline integrity is corrosion-caused metal loss. This type of defect can occur over the pipe body, seam or girth welds or even on heat affected zones. Pipeline remaining strength criterions are restricted or even prohibited for assessing corrosion defects coincident with weld regions. This present work investigated the reliability of the most common assessment criteria for corroded pipes when defects were coincident with seam weld region in submerged arc welded pipes. The tested specimens were C-Mn steel pipe, from a pipeline manufactured in the 60´s and had operated for over 30 years. Five external defects were created on five pipe specimens and pressure tested until rupture. Stress, charpy V-notch and bending tests were carried out to find the mechanical properties of the welded joints. Microstructure and chemical composition from base metal and weld metal were also analyzed. Residual stresses on welds were measured. The level 1 criterion (ASME B31G, 085dL, RPA, DNV single and PCORRC) applications have underestimated failure pressure for spherical shaped defects. On the other hand, the same criterions have overestimated failure pressure for rectangular shaped defects. The level 2 criterions (Effective Area e DNV complex geometry) application overestimated failure pressure for all 5 specimens with both spherical and rectangular shaped defects. Fracture analyses have indicated that no specimen had a toughness controlled failure. Internal pit corrosion that was found after pressure testing is recognized as the most probable cause of underestimated pressure forecasts.

El Museo de Sitio Bodega y Quadra es el primer museo de sitio del Centro Histórico que muestra detalles del estilo de vida en la Lima antigua. Declarada Patrimonio Cultural Inmueble Colonial por el INC, actual Ministerio de Cultura; es por ello que consideramos importante realizar la evaluación estructural del mismo ante un evento sísmico severo. Dicha evaluación se ha realizado mediante el programa “VisualFEA”, el cual se basa en la teoría de los elementos finitos, además se ha respetado la norma de diseño peruana y las consideraciones necesarias por ser, la estructura en estudio, un monumento histórico. La presente es una investigación aplicada, cuantitativa, explicativa y descriptiva; de diseño no experimental, transversal y prospectivo. Se concluye que la estructura no cumple los desplazamientos mínimos, según norma, al someterla al sismo severo; por lo que se procede a plantear la propuesta de reforzamiento estructural haciendo uso de las técnicas de reconstrucción local y refuerzo externo, evitando afectar la integridad y la autenticidad de los materiales por tratarse de un patrimonio cultural. The museum of site Bodega y Quadra is the first museum of the historic center which shows the old´s life style of lima citizen. It was named Cultural Heritage Colonial Property by the Ministerio de la Cultura; because of that reason we considered important to realize the structural assessment of this museum to prevent any problem in case of a severe earthquake. This thesis has been done using the “VisualFEA” software which is based on the theory of the finite elements, besides it has been considered the Peruvian regulation of design and the properly considerations since it is a Heritage Property. This is an applied, quantitative, descriptive and explanatory research; design not experimental, transversal and prospective. Concludes that the structure does not meet minimum displacement, as a rule, when subjected to sever earthquake; so it proceeds to raise the proposed structural reinforcement using the local reconstruction technique and external reinforcement, preventing affect the integrity and authenticity of the materials because it is a historical monument.

[pt] Essa tese apresenta as questões experimentais relativas à avaliação da saúde de estruturas de concreto com o objetivo de propor uma alternativa à avaliação subjetiva tradicional de estruturas civis, complementando-a com uma avaliação mais objetiva utilizando o GPR. A ênfase foi na validação de um procedimento sólido de avaliação da saúde de edifícios, de estações de tratamento de águas residuais e de túneis. O GPR foi escolhido por ser considerado um dos métodos de ensaios não destrutivos mais adotados para investigação de estruturas de concreto devido à sua relativa insensibilidade às condições ambientais, ter alta resolução, eficácia e disponibilidade de resultados preliminares em tempo real. A pesquisa desenvolvida nessa tese teve ênfase na verificação de as-built da construção, detecção de danos, locação e quantificação de armadura que são de grande interesse no contexto do controle estrutural. Os resultados apresentados nessa tese demonstram que o Ground Penetrating Radar (GPR) pode ser uma ferramenta muito útil para produzir projetos de detalhamento estrutural já que ele pode estimar espessura de recobrimento de concreto e profundidade e locação do reforço. Os resultados também mostram que a deterioração do concreto, bem como a corrosão das barras podem ser verificados após a análise de atributos fornecidos pela verificação feita com o GPR. Danos são detectados por meio da redução da profundidade do refletor, aumentando a amplitude das ondas eletromagnéticas e aumentando a atenuação expressa pelo gráfico de dB decay. Além disso, também verificou-se que a condição da barra de aço pode ser avaliada através de fatias em diferentes tempos/profundidade, obtidas na prospecção tridimensional. Adicionalmente, o programa experimentado também avaliou a viabilidade de empregar o GPR na avaliação da distribuição de fibras de aço em revestimento de túnel de concreto projetado, considerando-se o GPR como uma ferramenta útil para monitoramento e mapeamento in situ durante a o método de construção NATM de túneis. Os resultados dos ensaios realizados em prismas de concreto auto adensável reforçado com fibra de aço demonstraram que a distribuição das fibras não é uniforme. O processamento digital de imagem mostrou que as fibras não são distribuídas uniformemente e há variação do número de fibras em diferentes seções do prisma. A análise estatística realizada nos resultados também identificou que a distância entre as fibras também varia. Quando compara-se os resultados obtidos com o GPR e os resultados obtidos das análises digitais de imagens percebe-se uma boa relação entre ambos. Também foi observado que a amplitude do sinal do GPR não apenas fornece informações sobre a distribuição das fibras, mas também sobre regiões com ausência delas. Com base nos resultados do programa experimental, acredita-se que o GPR possa fornecer um feedback imediato das informações e pode ser usado como uma ferramenta de ajuste dinâmico no projeto NATM. / [en] This thesis presented the experimental issues concerning the health assessment of concrete structures with the desire to replace the traditional subjective assessment of civil structures with a more objective assessment using the GPR. The emphasis here was on validating a sound procedure of health assessment for buildings, wastewater treatment stations and concrete test specimens. GPR was chosen since it is considered one of the most popular non-destructive testing methods adopted for concrete structure imaging because of its relative insensitivity to ambient conditions, high resolution, effectiveness, and availability of real-time images The research carried out in this thesis emphasized on as-built designing, damage detection, location, and quantification, which is of interest in the context of structural control. The results presented in this thesis demonstrated that the groundpenetrating radar (GPR) could be used as a useful tool in producing structural detailing drawings since it can provide the thickness of covering concrete and the depth and location of reinforcement. The results also show that deterioration of concrete mass and corrosion of its rebars could be also be assessed by the attributes provided by a GPR scan. Damages are detected by reducing the depth of the reflector, increasing the amplitude of EM waves and increasing attenuation expressed by the dB decay. Further to these, it was also indicated that the rebar condition can be assessed through slices at different times/depths obtained from a 3-D survey. In addition to that, the program also assessed the feasibility of GPR in evaluating steel fiber distribution within short beam test specimens used in several standard test methods for determining mechanical properties. Results revealed that the distribution of steel fibers within a beam is not uniform. Digital and processed images showed that fibers are not evenly distributed and there is a disparity between the numbers of fibers in different sections of the short beam. A statistical analysis performed on the results also found that the distance between fibers also varies within the short beam. When sketches of the emitted and recorded GPR signal in a single radar trace mode are compared to the digital and processed images it was perceived a good relationship between the GPR signal and the distribution of steel fibers within the short beam. It was additionally noticed that GPR signal amplitude not only supplies information on how the fibers are close to each other but also reflects regions with the absence of fibers. Results have also shown that a GPR system using a high-frequency antenna could assess weaker zones of steel fiber reinforcement within self-consolidating concrete short beams.

L’objectif de ce travail est de proposer une méthode d’analyse de vulnérabilité sismique adaptée à l’étude d’un patrimoine historique complet très étendu, indépendamment de la renommée de chaque bâtiment. En effet la grande vulnérabilité sismique du patrimoine ancien, très souvent en maçonnerie, impose, afin d’éviter tout dommage irréparable, de se donner les moyens d’intervenir en amont. Notre démarche doit donc répondre à trois impératifs principaux: développer des outils de choix à grande échelle afin de hiérarchiser les besoins, offrir une analyse pertinente du comportement sous séisme d'une structure historique maçonnée même en première approche, et trouver des méthodes pour gérer le nombre important d’incertitudes qui caractérise le diagnostic des édifices anciens. Pour ce faire, nous étudions les églises et chapelles baroques des hautes vallées de la Savoie française, témoignages d'une période particulièrement prospère dans l'histoire de la Savoie et d'un mouvement artistique unique dans un environnement hostile. Dans ce contexte nous avons donc développé ou adapté différents outils afin de pouvoir traiter les particularités des édifices anciens et utiliser pour des édifices anciens en maçonnerie rustique les potentialités des techniques proposées pour les édifices modernes : modélisations numériques non-linéaires dynamiques temporelles, mesures vibratoires in-situ, analyse multi modale non-linéaire. / The aim of this thesis is to propose a seismic vulnerability assessment method well suited to the study of a complete historical heritage, regardless of the prestige of each building. Indeed the great seismic vulnerability of the historical heritage, often in masonry, requires to act preventively in order to avoid irreparable damage. Our approach must tackle three main requirements: to develop large-scale tools of choice to prioritize the needs, to provide relevant analysis of seismic behavior on the structural scale even in the first study, and to manage the large number of uncertainties characterizing the old buildings structural assessment. To this aim, we study the baroque churches and chapels in the high valleys of the French Savoie. They witness to a particularly prosperous period in the history of Savoy and a unique artistic movement adapted to a harsh environment. In this context we have therefore developed or adapted different tools in order to handle the peculiarities of the old buildings. This way we can use the today proposed techniques for modern buildings to study these ancient buildings in rustic masonry: non-linear temporal dynamics numerical modeling, vibratory in situ measurements, non-linear multi modal analysis.