The diploma thesis is focused on a design and appraisal of a steel load bearing construction of footbridge. The footbridge builds a new bridge across the river Ostravice in Sviadnov at Frýdek-Místek. The main subject of the diploma thesis was preparation of three variants for the footbridge. All variants were evaluated and the best one was elaborated in depth. It is a footbridge with a total span of 57 metres with a load bearing construction created two arches bent down to each orther. There is an orthotropic bridge deck with main outer lenghthways girders on the arches.

The subject of this diploma’s thesis is design of the footbridge over Radlická street in Prague. Total length of the footbridge is about 90 m. Three variant designs were made with different systems of static construction. Based on the multi-criteria analysis, the most suitable variant was chosen. The variant A, a continuous truss beam, was chosen for detailed design. It is a truss footbridge with a lower orthotropic deck without a wind bracing. The stability of the upper chord is secured by frame stiffness of verticals and stiffness of the floor beam. Detailed static calculation includes assessment of load-bearing parts of the structure and assessment of welds. The structure is made of steel class S335. Assessment and dimensioning were designed according to valid standards ČSN EN 1990-1993.

Master of Science / Department of Mechanical and Nuclear Engineering / Youqi Wang / Two fiber reinforced polymer (FRP) bridge deck specimens were analyzed by means of acoustic emission (AE) monitoring during a series of loading cycles performed at various locations on the composite sandwich panels' surfaces. These panels were subjected to loads that were intended to test their structural response and characteristics without exposing them to a failure scenario. This allowed the sensors to record multiple data sets without fear of having to be placed on multiple panels that could have various characteristics that alter the signals recorded. The objective throughout the analysis ias to determine how the acoustic signals respond to loading cycles and various events can affect the acoustical data. In the process of performing this examination several steps were taken including threshold application, data collection, and sensor location analysis. The thresholds are important for lowering the size of the files containing the data, while keeping important information that could determine structurally significant information. Equally important is figuring out where and how the sensors should be placed on the panels in the first place in relation to other sensors, panel features and supporting beams. The data was subjected to analysis involving the response to applied loads, joint effects and failure analysis. Using previously developed techniques the information gathered was also analyzed in terms of what type of failure could be occurring within the structure itself. This somewhat aided in the analysis after an unplanned failure event occurred to determine what cause or causes might have lead to the occurrence. The basic analyses were separated into four sets, starting with the basic analysis to determine basic correlations to the loads applied. This was followed by joint and sensor location analyses, both of which took place using a two panel setup. The last set was created upon matrix failure of the panel and the subsequent investigation.

In this thesis technical and economic analysis of Fiber Reinforced Composite Polymer (FRPC) bridges was performed. Current condition and main issues of conventional bridges in the world and in Lithuania are assessed, main defects are indicated. In this thesis FRPC is considered as an alternative solution for bridge construction. Application range of FRPC for bridge construction is classified and actual bridge examples are analysed. Further, main properties of FRPC are introduced, taking into account influence of material composition, manufacturing technology, long term effects and advantages over conventional materials. Load-deformation, failure behavior analysis of FRPC bridge decks and bridges revealed advantages over conventional bridge solutions and design issues. In addition, existing codes for FRPC bridge design are analysed, design peculiarities are emphasized and current problems are identified. Performed Life Cycle Cost (LCC) analysis revealed financial viability of FRPC bridges. Finally, main conclusions and problems to be solved are stated and FRPC application potential for bridges construction in Lithuania is suggested. Performed analysis revealed that FRPC application for bridges construction is technically and economically viable solution. / Šiame magistriniame darbe atlikta Pluoštais Armuotų Polimerinių Kompozitinių (PAPK) tiltų techninė ir ekonominė analizė. Nagrinėjama esama pasaulio ir Lietuvos tiltų būklė, nustatytos būdingos problemos bei defektai. Šiame darbe PAPK yra svarstoma kaip alternativi medžiaga tiltų statybai. Atlikta PAPK panaudojimo klasifikacija tiltų statybai, analizuojami esami PAPK tiltų pavyzdžiai bei jų paplitimas. Toliau nustatomos mechaninės bei fizinės PAPK savybės, atsižvelgiant į medžiagos sandarą, gamybos būdą, ilagalaikius veiksnius ir privalumus lyginant su plienu ir gelžbetoniu. Pagal atliktą PAPK tiltų ir perdangų apkrovos-deformacijų, suirimo analizę nustatyta elementų elgsena, pateiktos pagrindinės problemos bei privalumai palyginus su tradiciniais tiltų sprendiniais. Taip pat išnagrinėtos PAPK tiltų projektavimų normos, pateikti skaičiavimų ypatumai bei problemos. Paskutiniame skyriuje atlikta Gyvavimo Ciklo Kainos analizė parodė PAPK tiltų finansinį įgyvendinamumą. Darbo pabaigoje pateikiamos pagrindinės išvados, rezultatai, spręstinos problemos bei PAPK tiltų panaudojimo rekomendacijos Lietuvoje. Atlikta techninė ir ekonominė analizė parodė, jog PAPK panaudojimas tiltų statybai yra techniškai ir ekonomiškai efektyvus sprendimas.

The first part of the thesis addresses the fatigue performance of concrete bridge decks with GFRP stay-in-place structural forms replacing the bottom layer of rebar. The forms were either flat plate with T-up ribs joined using lap splices, or corrugated forms joined through pin-and-eye connections. The decks were supported by simulated Type III precast AASHTO girders spaced at 1775mm (6ft.). Two surface preparations were examined for each GFRP form, either using adhesive coating that bonds to freshly cast concrete, or simply cleaning the surface before casting. For the bonded deck with flat-ribbed forms, adhesive bond and mechanical fasteners were used at the lap splice, whereas the lap splice of the unbonded deck had no adhesive or fasteners. All the decks survived 3M cycles at 123kN service load of CL625 CHBDC design truck. The bonded flat-ribbed-form deck survived an additional 2M cycles at a higher load simulating a larger girder spacing of 8ft. Stiffness degradations were 9-33% with more reduction in the unbonded specimens. Nonetheless, live load deflections of all specimens remained below span/1600. The residual ultimate strengths after fatigue were reduced by 5% and 27% for the flat-ribbed and corrugated forms, respectively, but remained 7 and 3 times higher than service load. The second part of the thesis investigates the performance of bridge deck overhangs reinforced by GFRP rebar. Overhangs of full composite slab-on-girder bridge decks at 1:2.75 scale were tested monotonically under an AASHTO tire pad. Five tests were conducted on overhangs of two lengths: 260mm and 516mm, representing scaled overhangs of 6ft. and 8ft. girder spacing, respectively. The 260mm overhang was completely reinforced with GFRP rebar while the 516mm overhang consisted of a GFRP-reinforced section and a steel-reinforced section. The peak loads were approximately 2 to 3 times the established equivalent service load of 24.3kN, even though the overhangs were not designed for flexure according to the CHBDC but rather with lighter minimum reinforcement in anticipation of shear failure. The failure mode Abstract ii of each overhang section was punching shear. The steel-reinforced overhang section exhibited a greater peak load capacity (13.5%) and greater deformability (35%) when compared to the GFRP-reinforced overhang section. / Thesis (Master, Civil Engineering) -- Queen's University, 2013-09-17 18:54:18.131

In this thesis, a load path caused by arching action in reinforced concrete slabs is described and validated using a three-dimensional model. Currently, the CHBDC enforces a 4 meter girder spacing requirement in the design of deck slabs. The aim of this thesis is to investigate the load path induced by arching action in deck slabs with a wide range of girder spacing. To do this, a two-dimensional model was developed to examine the path of horizontal stress and was validated using a FEM. A parametric study showed that girder spacing does not affect the development of restraining stress while cantilever width does. As well, cracking of the slab is necessary for arching action to occur. These results help with future development of a rational model to be used by bridge designers.

Master of Science / Department of Civil Engineering / Robert J. Peterman / Epoxy polymer overlays have been used for decades on existing bridge decks to protect the deck and extend its service life. The polymer overlay’s ability to seal a bridge deck is now being specified for new construction. Questions exist about the amount of drying time needed to achieve an acceptable concrete moisture content to ensure an adequate bond to the polymer overlay. Current Kansas Department of Transportation (KDOT) specifications for new bridge decks call a 14 day wet curing period followed by 21 days of drying (Kansas DOT, 2007) If not enough drying is provided, the moisture within the concrete can form water vapor pressure at the overlay interface and induce delamination. If too much drying time is provided projects are delayed, which can increase the total project cost or even delay overlay placement until the next spring. A testing procedure was developed to simulate a bridge deck in order to test the concrete moisture content and bonding strength of the overlay. Concrete slabs were cast to test typical concrete and curing conditions for a new bridge deck. Three concrete mixtures were tested to see what effect the water –cement ratio and the addition of fly ash might have on the overlay bond strength. Wet curing occurred at 3 different temperatures (40°F, 73°F, and 100°F) to see if temperature played a part in the bond strength as well. The concrete was then allowed to dry for 3, 7, 14, or 21 days. Five epoxy-polymer overlay systems that had been preapproved by KDOT were each used in conjunction with the previously mentioned concrete and curing conditions. After, the slabs were setup to perform pull-off tests to test the tensile rupture strength. The concrete slabs with the different epoxy overlays were heated to 122-125°F to replicate summer bridge deck temperatures. Half of the pull-off tests were performed when the slabs were heated and half were performed once the slabs had cooled back down to 73°±5°F. Results from the pull-off tests as well as results from a moisture meter taken on the concrete prior to the overlay placement were compared and analyzed. Testing conditions were compared with each other to see which had a larger effect on the epoxy polymer overlay’s bond strength.

Master of Science / Department of Civil Engineering / Hani G. Melhem / Fiber Reinforced Polymer (FRP) is a relatively new material used in the field of civil engineering. FRP is composed of fibers, usually carbon or glass, bonded together using a polymer adhesive and formed into the desired structural shape. Recently, FRP deck panels have been viewed as an attractive alternative to concrete decks when replacing deteriorated bridges. The main advantages of an FRP deck are its weight (roughly 75% lighter than concrete), its high strength-to-weight ratio, and its resistance to deterioration. In bridge design, AASHTO provides load distributions to be used when determining how much load a longitudinal beam supporting a bridge deck should be designed to hold. Depending on the deck material along with other variables, a different design distribution will be used. Since FRP is a relatively new material used for bridge design, there are no provisions in the AASHTO code that provides a load distribution when designing beams supporting an FRP deck. FRP deck panels, measuring 6 ft x 8.5’, were loaded and analyzed at KSU over the past 4 years. The research conducted provides insight towards a conservative load distribution to assist engineers in future bridge designs with FRP decks. Two separate test periods produced data for this thesis. For the first test period, throughout the year of 2007, a continuous FRP panel was set up at the Civil Infrastructure Systems Laboratory at Kansas State University. This continuous panel measured 8.5 ft by 6 ft x 6 in. thick and was supported by 4 Grade A572 HP 10 x 42 steel beams. The beam spacing’s, along the 8.5 ft direction, were 2.5 ft-3.5 ft-2.5 ft. Stain gauges were mounted at mid-span of each beam to monitor the amount of load each beam was taking under a certain load. Linear variable distribution transformers (LVDT) were mounted at mid-span of each beam to measure deflection. Loads were placed at the center of the panel, with reference to the 6 ft direction and at several locations along the 8.5 ft direction. Strain and deflection readings were taken in order to determine the amount of load each beam resisted for each load location. The second period of testing started in the fall of 2010 and extended into January of 2011. This consisted of a simple-span/cantilever test set-up. The test set-up consisted of, in the 8.5 ft direction, a simply supported span of 6 ft with a 2.5 ft cantilever on one side. As done previously both beams had strain gauges along with LVDTs mounted at mid-span. There were also strain gauges were installed spaced at 1.5ft increments along one beam in order to analyze the beam behavior under certain loads. Loads were once again applied in the center of the 6 ft direction and strain and deflection readings were taken at several load locations along the 8.5 ft direction. The data was analyzed after all testing was completed. The readings from the strain gauges mounted in 1.5 ft increments along the steel beam on one side of the simple span test set-up were used to produce moment curves for the steel beam at various load locations. These moment curves were analyzed to determine how much of the panel was effectively acting on the beam when loads were placed at various distances away from the beam. Using these “effective lengths,” along with the strain taken from the mid-span of each beam, the loads each beam was resisting for different load locations were determined for both the continuously supported panel and the simply supported/cantilever panel data. Using these loads, conservative design factors were determined for FRP panels. These factors are S/5.05 for the simply supported panel and S/4.4 for the continuous panel, where “S” is the support beam spacing. Deflections measurements were used to validate the results. Percent errors, based on experimental and theoretical deflections, were found to be in the range of 10 percent to 40 percent depending on the load locations for the results in this thesis.

In this thesis, we investigate flow past an array of micro-electro-mechanical-type (MEMS-type) heating elements placed on a flat surface, where MEMS devices have hump-shaped surfaces, using the triple deck theory. In this work we start by investigating the problem with a single heating element. MEMS devices can be used to control the fluid dynamics over the surface. Hence, we present a review of the boundary layer and the triple deck theories, followed by a literature review of the problem of flow past an array of MEMS devices. Next, we formulate our problem with the aid of the method of matched expansions for supersonic and subsonic flows. Thirdly, we solve analytically the linear version of the problem for supersonic flows. Thereafter, the non-linear problem is solved numerically where a detailed description of a hybrid method to solve the formulated non-linear problem for supersonic flow is exhibited. Fourthly, for subsonic flows we continue investigating flow past a heating element placed on a flat surface. Linear analysis of this problem is conducted. A novel numerical method to solve the non-linear problem for subsonic flows is described. The results are then discussed. In a similar context, we formulate a problem which can be considered as an the extension of previous subsonic flow problem to the three dimensional case. Analytical results are obtained using the Fourier transform where the linear approximation of the problem is considered and numerical results are then obtained using the Fast Fourier Transform. Finally, we consider a case of transonic flow past a heating element placed on a flat surface, where MEMS device has a hump-shaped surface. This transonic flow problem is non-linear in the upper deck and the lower deck equations where they should be solved simultaneously. Hence, a numerical method is required where we will use a finite difference method in stream-wise direction and Chebyshev collocation method in the wall normal direction. The results are then analysed. In conclusion, the use of localised heating elements in boundary layers for flow types considered in the thesis can contribute to the possibility of favourably controlling the fluid flow perturbations.

Dos sistemas de pontes suspensas por cabos, as estaiadas tem sido largamente utilizadas devido a sua capacidade de vencer grandes vãos e, além dessa vantagem estrutural, são esteticamente bem aceitas pela sociedade, valorizando o espaço urbano e muitas vezes tornando-o ponto de referência. Atualmente, em que a otimização da infraestrutura viária é de extrema importância, as pontes estaiadas são bastante exploradas por suas vantagens construtivas, não demandando grandes áreas de apoio durante a construção que possam interferir no fluxo de veículos ou embarcações existente. Em conjunto a isso, a escolha do tipo de obra de arte se deve a diversos outros fatores, tais como as condições locais da fundação, o consumo de materiais e mão de obra, facilidades construtivas, etc. Muitas vezes é necessário estudar outras formas de utilização desse tipo de estruturas, como é o caso de pontes curvas, em que um traçado reto não bastaria para transpor um obstáculo e respeitar o traçado projetado ao viário. Para isso, o conhecimento das técnicas e teorias que fundamentam pontes estaiadas curvas é requisito para o estudo de uma concepção mais favorável e/ou otimizada, onde devem ser avaliados todos os fatores que influem em seu comportamento. Este trabalho apresenta a avaliação de esforços no tabuleiro e no mastro para diversos modelos estruturais. Na primeira etapa será discutida a forma de concepção dos modelos aplicados a um estudo de caso através de comparação dos esforços para avaliar a viabilidade de simular o tensionamento inicial nos cabos através da aplicação de uma queda de temperatura. Em seguida, serão avaliados os efeitos da posição do mastro e do posicionamento unilateral dos estais, permitindo obter a configuração que apresente um melhor desempenho geral. Por fim, as análises serão aplicadas a um estudo de caso com tabuleiro de maior largura. Dos resultados obtidos verificou-se que a configuração de tabuleiro suspenso pelo lado interno, única que não invade o gabarito de pedestres ou veículos, se mostrou viável sem, contudo, apresentar todas as vantagens estruturais, de modo que há torção significativa. Em compensação, a flexão se mostrou reduzida. / In systems of suspended cable bridges, the cable-stayed bridges had been widely used because of its capacity to overcome large spans and for being aesthetically well accepted by society, valuing the urban space and often making it a landmark. Currently, where the optimization of road infrastructure is of utmost importance, cable-stayed bridges are quite exploited by their constructive advantages, not requiring large areas of support during construction that may affect the existing traffic flow. In addition to this, the choice of the type of structure is due to several other factors such as local conditions of the foundation, the consumption of materials and labor, construction facilities, etc. It is necessary to study other forms of use of such structures, as in the case of curved bridges, where a straight path would not be enough to overcome an obstacle and respect the geometry of the road. For this, the knowledge of the techniques and theories behind curved cable-stayed bridges is a requisite for the study of a more favorable and/or optimized design, where all the factors that influence their behavior should be evaluated. This paper presents the assessment of forces on the deck and pylon for several structural models. In the first step, the models design will be discussed applied to a case by comparing the forces to evaluate the feasibility of simulating the initial tensioning in the cables through the application of a temperature drop. Next, the effects of the pylon position and the unilateral positioning of the cables will be evaluated, allowing to obtain the configuration that presents a better overall performance. Finally, the analyzes will be applied to a case with a wider deck. From the obtained results, it has been found that the configuration of deck suspended by the inner side, which does not invade the pedestrian or vehicle clearance, has proved to be feasible without, however, presenting all the structural advantages, so that there is significant torsion. In contrast, flexion was reduced.