京都大学 / 新制・課程博士 / 博士(工学) / 甲第24578号 / 工博第5084号 / 新制||工||1974(附属図書館) / 京都大学大学院工学研究科建築学専攻 / (主査)教授 西山 峰広, 教授 聲高 裕治, 准教授 倉田 真宏 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Concentrically braced frames (CBFs) have been widely used in seismic areas as efficient structural systems to provide both lateral stiffness and strength. They dissipate earthquake energy through the inelastic deformation of the braces in both tension and compression. While these frames are efficient in providing lateral stiffness and strength, their inelastic mechanism is not ductile when compared to other systems such as moment resisting frames (MRFs). This student proposes a new approach to enhance the ductile behavior of CBFs by locally heat treating gusset plate connections or braces. In this method, the steel is heated locally to austenitizing temperature and then cooled with the appropriate rate to achieve the desired material properties. In gusset plate connections, to permit the rotation imposed from brace buckling, the conventional approach is to use linear fold lines, which can result in overly large plates. A more compact design uses elliptical fold lines, but both designs can lead to damage to welds with surrounding components. To enhance the performance of the gusset plate connection, a yield path is defined with a locally weakened zone within a high strength steel gusset plate. The weakened zone, created through heat treatment concentrated the inelastic deformation, resulting in an efficiently sized connection in which the failure mechanism is tightly controlled. A design methodology for the heat treated gusset plate is proposed, and finite element analysis is used to analyze the behavior of the heat treated gusset plates. In conventional braces, repeated buckling leads to deterioration and low-cycle fatigue which limits the ductility capacity of the CBF, compared to MRFs. As a novel approach, heat treatment is used to increase the local yield strength in the brace. Through this method, the buckling is permitted to occur, but an enhancement in the buckling behavior is intended. Various heat treated configurations are investigated, and finite element analysis is used to compare the behavior of heat treated braces. / Thesis / Master of Applied Science (MASc)

The research summarized in this thesis is comprised of an experimental analysis of the mechanical behavior of a wood composite I-joist with different bracing configurations exposed dynamic walking loads. Three 16 in. deep GPI® 65 I-joists were simply supported and laid parallel to each other, while the bracing was attached to the top flange. Five different brace stiffnesses were used: zero stiffness (control), 1.2 lb/in., 8.5 lb/in., 14.0 lb/in. and infinitely stiff. Two different brace configurations were used: one-quarter of the span length (60 in.) and one third the span length (80 in.). The dynamic walking loads consisted of human test subjects attached to a safety platform walking across the I-joist at a designated pace. Experimental results for this research consisted of the I-joist's lateral accelerations, lateral displacements and twist. An Analysis of Covariance (ANCOVA) was used for the statistical analysis of the results and was performed for each measurement. The statistical analysis determined the effects of different bracing configurations, stiffnesses, measurement locations as well as test subjects' weight and occupation. Test results and observed trends are provided for all test configurations. Lateral displacement and twist experienced the same trend throughout the experiment: as brace stiffness increased, lateral displacement and twist decreased. This correlated with basic beam theory and bracing fundamentals. It should be noted that as the stiffness increased, the effect on lateral displacement and twist response decreased. However, the trend for lateral displacement and twist was not observed for the lateral accelerations. The 1.2 lb/in. brace stiffness had much larger lateral accelerations for the 60 in. brace configuration throughout the span and were also larger at the bracing point for the 80 in. brace configuration. This could have been due to the energy applied from the springs or a natural frequency of the I-joist system could have been reached during testing. However, the other four brace stiffnesses followed the same trend as the lateral displacements and twist. In addition, this research demonstrates a method for the measurement of lateral buckling due to worker loads. The mitigation of lateral buckling can use appropriate bracing systems. The measurements of the change in lateral buckling behavior can be used to develop safety devices and ultimately ensure the protection of construction workers. / Master of Science

The objective of this study was to develop design equations that predict lateral restraint forces in two commonly used Z-purlin supported roof systems. These are quarter point bracing and third point plus support bracing. To that end, a stiffness model used in the past has been reintroduced. This model has been modified slightly to better represent roof system behavior. The updated stiffness model was then used to estimate lateral restraint forces for a number of roof systems with a varying cross sectional dimensions of the purlin, number of purlin lines, number of spans, and span length. A regression analysis was then performed on the data to obtain empirical design equations similar to those found in the 1996 Edition of the American Iron and Steel Institute's Specification for the Design of Cold-Formed Steel Members, Section D.3.2.1. <i>Vita removed April 4, 2011. GMc</i> / Master of Science

I vissa takstolskonstruktioner kan det ibland uppstå stora tryckkrafter i diagonala reglar. I Sverige löser man oftast detta med hjälp av stagning tvärs diagonalen för att hindra utböjning i veka riktningen. Ibland när det är svårt att på plats trä in strävor på grund av utrymmesbrist och dylikt kan man spika eller skruva på en regel för att på så sätt förstärka den diagonala strävan. Detta examensarbete har undersökt två olika förstärkningsalternativ, rektangulärt- och T-tvärsnitt, med hjälp av reglar med dimension 45x95 mm2 vilka skruvas respektive spikas ihop. Detta har gjorts laborativt genom att trycka provkroppar i en provningsram och undersöka hur mycket den axiala kapaciteten ökar med förstärkning. De två olika förstärkningslösningarna bygger på att man på plats kan förstärka strävor med enkla medel. Testbitarna har levererats till Växjö universitet och är av oklassat virke. Provbitarnas E-modul har undersökts för att på teoretisk väg undersöka hur stor axialkraftskapacitet den primära strävan har utan förstärkning. Provkroppar tillverkades och konditionerades i klimatrum, med temperaturen 20°C och 65 % RF, i ca tre veckor före provtryckning. De laborativa värdena visar att den axiella kapaciteten ökar med 1,9 – 2,7 ggr för de rektangulära tvärsnitten och 2,5 – 4,0 ggr för T-tvärsnitten. Förstärkningsfaktorn är beroende av längd, förstärkningsalternativ och sammanfogning. Förstärkningseffektiviteten är högst för de längre strävorna. / In wooden roof trusses there sometimes may occur buckling in compressed web members. In most cases in Sweden this is solved by bracing between two webs to prevent buckling of the minor axis. Sometimes it is hard to brace between webs because of lack of space. Then it is possible to nail or screw a side member on the compressed web to increase the capacity. This diploma work has examined two different ways of bracing, rectangular cross section and T-bracing, with webs 45x95 mm2. Experimental tests have been made on compression webs and examine the bracing efficiency. It is important that the bracing alternatives are easy to use with simple tools. Ungraded lumber were delivered to Växjö University. The Youngs modulus of the test pieces has been examined so the critical buckling load of the main member without bracing could be calculated theoretically. The lumber was conditioned to equilibrium moisture content of approximately 12 percent in a room maintained at 65 percent relative humidity and 20°C in three weeks before testing the critical buckling load. The experimental results show that the critical buckling load increases with a factor of 1,9 – 2,7 for the rectangular cross sections and with a factor of 2,5 – 4,0 for the T-bracing. The bracing efficiency is dependent on length, bracing alternative and type of connectors.. The bracing efficiency increases for longer webs.

Deficient concrete structures are serious danger in seismic zones. In order to minimize economical and human loss, these structures should be retrofitted. Selecting suitable retrofitting schemes requires detailed investigation of these systems. Considering these facts, this study aims to calibrate analytical models of systems with chevron braces and internal steel frames / and evaluate their seismic performances. First, analytical models of the frames with braces and internal steel frames were prepared and then their responses were compared with cyclic responses of experimental studies. Results of these models were used to determine performance limits by the methods proposed by TEC2007 and ASCE/SEI-41. Then, calibrated models were employed for time history analyses with various scales of Duzce ground motion and analytical results were compared with experimental findings. Seismic performance of these systems was also evaluated by using aforementioned codes. Finally, evaluated retrofitting schemes were applied to a 4-story 3-bay reinforced concrete frame that was obtained from an existing deficient structure and effectiveness of applied retrofitting schemes was investigated in detail.

This thesis examines the seismic internal retrofitting of existing deficient reinforced concrete (RC) structures by using structural steel members. Both experimental and numerical studies were performed. The strengthening methods utilized with the scope of this work are chevron braces, internal steel frames (ISFs), X-braces and column with shear plate. For this purpose, thirteen strengthened and two as built reference one bay one story portal frame specimens having 1/3 scales were tested under constant gravity load and increasing cyclic lateral displacement excursions. In addition, two &frac12 / scaled three bay-two story frame specimens strengthened with chevron brace and ISF were tested by employing continuous pseudo dynamic testing methods. The test results indicated that the cyclic performance of the Xbrace and column with shear plate assemblage technique were unsatisfactory. On the other hand, both chevron brace and ISF had acceptable cyclic performance and these two techniques were found to be candidate solutions for seismic retrofitting of deficient RC structures. The numerical simulations by conducting nonlinear static and dynamic analysis were used to estimate performance limits of the RC frame and steel members. Suggested strengthening approaches, chevron brace and ISF, were also employed to an existing five story case study RC building to demonstrate the performance efficiency. Finally, design approaches by using existing strengthening guidelines in Turkish Earthquake Code and ASCE/SEI 41 (2007) documents were suggested.

<p>I vissa takstolskonstruktioner kan det ibland uppstå stora tryckkrafter i diagonala reglar. I Sverige löser man oftast detta med hjälp av stagning tvärs diagonalen för att hindra utböjning i veka riktningen. Ibland när det är svårt att på plats trä in strävor på grund av utrymmesbrist och dylikt kan man spika eller skruva på en regel för att på så sätt förstärka den diagonala strävan. Detta examensarbete har undersökt två olika förstärkningsalternativ, rektangulärt- och T-tvärsnitt, med hjälp av reglar med dimension 45x95 mm2 vilka skruvas respektive spikas ihop. Detta har gjorts laborativt genom att trycka provkroppar i en provningsram och undersöka hur mycket den axiala kapaciteten ökar med förstärkning. De två olika förstärkningslösningarna bygger på att man på plats kan förstärka strävor med enkla medel.</p><p>Testbitarna har levererats till Växjö universitet och är av oklassat virke. Provbitarnas E-modul har undersökts för att på teoretisk väg undersöka hur stor axialkraftskapacitet den primära strävan har utan förstärkning. Provkroppar tillverkades och konditionerades i klimatrum, med temperaturen 20°C och 65 % RF, i ca tre veckor före provtryckning.</p><p>De laborativa värdena visar att den axiella kapaciteten ökar med 1,9 – 2,7 ggr för de rektangulära tvärsnitten och 2,5 – 4,0 ggr för T-tvärsnitten. Förstärkningsfaktorn är beroende av längd, förstärkningsalternativ och sammanfogning. Förstärkningseffektiviteten är högst för de längre strävorna.</p> / <p>In wooden roof trusses there sometimes may occur buckling in compressed web members. In most cases in Sweden this is solved by bracing between two webs to prevent buckling of the minor axis. Sometimes it is hard to brace between webs because of lack of space. Then it is possible to nail or screw a side member on the compressed web to increase the capacity. This diploma work has examined two different ways of bracing, rectangular cross section and T-bracing, with webs 45x95 mm2. Experimental tests have been made on compression webs and examine the bracing efficiency. It is important that the bracing alternatives are easy to use with simple tools.</p><p>Ungraded lumber were delivered to Växjö University. The Youngs modulus of the test pieces has been examined so the critical buckling load of the main member without bracing could be calculated theoretically. The lumber was conditioned to equilibrium moisture content of approximately 12 percent in a room maintained at 65 percent relative humidity and 20°C in three weeks before testing the critical buckling load.</p><p>The experimental results show that the critical buckling load increases with a factor of 1,9 – 2,7 for the rectangular cross sections and with a factor of 2,5 – 4,0 for the T-bracing. The bracing efficiency is dependent on length, bracing alternative and type of connectors.. The bracing efficiency increases for longer webs.</p>

Ces travaux s'inscrivent dans le cadre d'un projet de recherche translationnel visant à améliorer la conception des corsets orthopédiques de traitement de la scoliose par la mise en place, par méthode inverse, d'un modèle biomécanique global, simplifié et personnalisé, propre au tronc de chaque patient scoliotique. Ils constituent la première étape de ce projet, à savoir, développer et mettre en œuvre des techniques, outils et protocoles permettant, d'une part, la construction d'un modèle géométrique 3D de la surface externe et des éléments internes du tronc du patient à partir de radiographies bi-planes issues d'un équipement standard et du système Model Maker (Proteor), et d'autre part, la mesure des pressions exercées par le corset ainsi que leur recalage sur les géométries reconstruites. Des reconstructions géométriques 3D du tronc avec et sans corset ainsi que des mesures de pressions ont été réalisées pour 11 patients. La conception d'un unique dispositif de calibration associé à un protocole spécifique permet l'acquisition des différentes données quasi sans déplacements du patient. Sa facilité de transport, d'installation et son faible coût, associés à un temps d'acquisition ne pénalisant pas le confort du patient, rendent envisageable son utilisation en routine clinique. L'utilisation de modèles géométriques paramétriques, associée à des équations de prédiction des paramètres anatomiques, permet d'obtenir une initialisation rapide des géométries des éléments internes du tronc à partir d'un nombre réduit de points anatomiques à numériser. Les mesures de la pression exercée par le corset, effectuées à l'aide d'un dispositif innovant muni de capteurs entièrement réalisés en fibres textiles lui permettant d'épouser parfaitement les courbes anatomiques, ont mis en avant les variations de correction, non négligeables, qu'entraînent la modification de la position du patient. / This thesis is a part of a translational research project to improve scoliosis orthopedic brace design through the use, by inverse method, of a simplified and personalized comprehensive biomechanical model for each scoliotic patient’s trunk. It represents the first step of this project, namely, to develop and to implement methods, tools and protocols allowing, on one hand, 3D reconstruction of the external shape and internal components of patient’s trunk from biplanar X-rays (performed with a standard device) and the Model Maker system (Proteor), and on the other hand, measurements of the pressure infered by the brace and their registration on the reconstructed geometry. 3D modeling of the trunk with and without brace as well as pressure measurement were carried out on 11 patients. The development of a common calibration device associated to a specific protocol allows data acquisition nearly without displacements of the patient. Its ease of transportation, installation and a low cost associated with an acquisition time which not penalize the patient’s comfort make possible its use in clinical routine. The use of parametrics geometrical models associated with prediction equations of anatomical parameters provides fast initialization of the geometries of trunk’s internal elements from a reduced number of anatomical landmarks to digitize. Measurements of the pressure infered by the brace, performed thanks to an innovative device made of pressure-sensitive textile fibers allowing it to perfectly fit anatomical curves, have highlighted significant correction variations according to the patient’s position.

Master thesis is about increasing of protection the crew in race car with changes in its roll-over protective structure according to current safety rules. For examination was used the Finite Element Method. The products of this thesis are different variation of roll cages, which are tasked to increasing the safety of existent race car.