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京都大学 / 新制・課程博士 / 博士(工学) / 甲第23483号 / 工博第4895号 / 新制||工||1765(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 杉浦 邦征, 教授 清野 純史, 教授 八木 知己 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

The inverted-T bridge system is a rapid bridge construction technique that consists of precast inverted-T girders placed adjacent to one another and covered with a cast-in-place deck. This system was first implemented in the U.S. by the Minnesota Department of Transportation (Mn/DOT). This research focuses on improving the constructability of the Mn/DOT system while maintaining the system's structural performance characteristics. To accomplish this goal, five sub-assemblage specimens were cast and tested in the structures laboratory at Virginia Tech. These tests focused on identifying an improved precast girder geometry and transverse sub-assemblage connection for this system. From this study it was found that all of the proposed specimens behaved adequately at service load and strength. From these results, it is recommended to further evaluate a specimen with a tapered profile and no physical connection between precast girders for use in a Virginia Department of Transportation bridge near Richmond, VA. / Master of Science

Three series of tests were conducted on a sandwich plate bridge deck, which consisted of two steel plates and an elastomer core. The first series of testing was conducted by applying a static load on a full scale sandwich plate bridge deck panel. Local strains and deflections were measured to determine the panel's behavior under two loading conditions. Next, fatigue tests were performed on the longitudinal weld between two sandwich plate panels. Two connections were tested to 10 million cycles, one connection was tested to 5 million cycles, and one connection was tested to 100,000 cycles. The fatigue class of the weld was determined and an S-N curve was created for the longitudinal weld group. Finally, a series of experiments was performed on a half scale continuous bridge deck specimen. The maximum positive and negative flexural bending moments were calculated and the torsional properties were examined. Finite element models were created for every load case in a given test series to predict local strains and deflections. All finite element analyses were preformed by Intelligent Engineering, Ltd. A comparison of measured values and analytical values was preformed for each test series. Most measured values were within five to ten percent of the predicted values. Shear lag in the half scale bridge was studied, and an effective width to be used for design purposes was determined. The effective width of the half scale simple span sandwich plate bridge deck was determined to be the physical width. Finally, supplemental research is recommended and conclusions are drawn. / Master of Science

In Norway there are plans of a ferry-free European road E39 with crossings of eight deep and wide fjords. A newly developed bridge concept that could be used for some of these fjord-crossings is a chained floating bridge. One of the challenges for the chained floating bridge is to create a convenient shipping-lane under the bridge, where one suggestion is to connect the chained floating bridge with a single pylon cable-stayed bridge. The aim of this thesis is to design and evaluate a cable-stayed bridge in connection with a chained floating bridge. The purpose is to evaluate the feasibility of such a design by conducting a case study of the crossing of Bjørnefjorden. A design of a bridge is created for the case based on a literature study of conventional cable-stayed bridges. The bridge design is modelled, analyzed and the structural integrity is evaluated with SOFiSTiK (a finite element software for structural design) according to Eurocode. The study concludes that the concept is feasible for Bjørnefjorden by providing a possible design of a cables-stayed bridge connected to a chained floating bridge with conventional cross sections. The analysis in the thesis confirms the structural integrity of the consept. The bridge design’s main span is 300m long, it has a 25m wide steel box girder where the cables (φ140mm) are placed in two planes with a spacing of 15m along the girder. It has a 184 m high A-shaped pylon with a concrete box section from the foundation up to the girder level (+50m), to the top is a steel box (3.5x3.5m). The bridge is designed with material properties according to Eurocode, where steel class S355 and concrete C45 are used. A parametric research also verifies the design’s feasibility for other geometries of chained floating bridges - where the horizontal reactions on the cable-stayed bridge vary in a range of 107MN-242MN. The parametric research confirms that both the utilization of the cross section and the stability increases with the horizontal reaction from the chained floating bridge. The parametric study also concludes that a width of 8m between the pylon legs decreases the effect on the lower part of the pylon and the support reaction at the pylon when compared with a 12m and a 18m width. However, the average utilization of the girder, cable and steel part of the pylon increases when the 8m width is compared with a 12m or a 18m wide pylon. A fan or radial cable arrangement compared to harp design is more efficient for the cables and the displacements of the girder in Z-direction. They are however, less efficient for the bottom part of the pylon than the harp arrangement. / I Norge planeras en färjefri Europaväg E39, där åtta djupa och breda fjordar ska förbindas med broar eller tunnlar. För att korsa några av fjordarna utvecklas bla. ett brokoncept med kedjeflytbro. En av utmaningarna i konceptet är att skapa en farled för fartyg under bron. Ett förslag är att koppla ihop kedjeflybron med en ”halv” snedkabelbro som har en pylon (inte två), där farleden går under huvud­spannet till snedkabelbron. Avsikten med detta examensarbete är att konstruera och utvärdera en snedkabelbro ihopkopplad med en kedjeflytbro. Syftet är att utvärdera om konceptet med snedkabelbro är genomförbart, med hjälp av en fallstudie av Bjørnefjordsförbindelsen. En konventionell design av en snedkabelbro upprättas efter fallets villkor med hjälp av en literaturstudie. Designen modelleras, analyseras och dimensioneras enligt Eurokod med analysverktyget SOFiSTiK. Slutsatsen är att konceptet med en snedkabelbro ihopkopplad med en kedjeflytbro är genomförbart då det är möjligt att designa en sådan med konventionella tvärsnitt. Analysen i rapporten bekräftar att designen har tillräcklig bärförmåga. I designen är huvudspannet 300m långt och består av en 25m bred brobalk upphängd av (φ140mm) kablar placerade i två plan var 15m. Bron har en 184m hög A-formad pylon med ett lådtvärsnitt i betong från fundament till brobalksnivån (+50m), därifrån till pylontoppen är tvärsnittet en stålbox (3.5x3.5m). Bron är dimensionerad med materialparameterar enligt Eurokod, där stålkvalitet S355 och Betong C45 har använts. En utförd parameterstudie bekräftar också konceptets genomförbarhet för andra geometrier av kedjeflytbron – där den horisontella reaktionen på snedkabelbron varierar mellan 107MN och 242MN. Parameterstudein bekräftar att både utnyttjandet av tvärsnittskapasiteten och stabiliteten ökar med den horisontella reaktionen från kedjeflytbron. Dessutom konkluderar parameterstudien att bredden 8m mellan pylonbenen minskar lasteffekten på den nedre delen av pylonen och stödreaktionen vid pylonen jämfört med bredden 12m och 18m. Däremot ökar medelutnyttjandet av tvärsnittaskapasiteten för brobalken, kablarna och ståldelen av pylonen för bredden 8m jämfört med 12m eller 18m. En radiell- eller solfjäderformad kabelkonfiguration jämfört med parallellformad design är mer effektiv för kablarna och nedböjning av brobalken. De gör däremot så att den den nedre delen av pylonen får större snittkrafter än för den parallellformade kabelkonfigurationen.