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Nicholson, John Corbett. "Design of wind turbine tower and foundation systems: optimization approach." Thesis, University of Iowa, 2011. https://ir.uiowa.edu/etd/1042.
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A renewed commitment in the United States and abroad to electricity from renewable resources, such as wind, along with the recent deployment of very large turbines that rise to new heights, makes obtaining the most efficient and safe designs of the structures that support them ever more important. Towards this goal, the present research seeks to understand how optimization concepts and Microsoft Excel's optimization capabilities can be used in the design of wind turbine towers and foundations. Additionally, this research expands on the work of previous researchers to study how considering the tower and foundation as an integral system, where tower support conditions are not perfectly rigid, affects the optimal design. Specifically, optimization problems are formulated and solved with and without taking into account the effect of deflections, resulting from the foundation's rotational and horizontal stiffness, on natural frequency calculations. The general methodology used to transcribe the design of wind turbine towers and foundations into an optimization problem includes: 1) collecting information on design requirements and parameter values 2) deciding how to analyze the structure 3) formulating the optimization problem 4) implementation using Microsoft Excel. Key assumptions include: 1) use of an equivalent lumped mass method for estimating natural frequency 2) International Electrotechnical Commission (IEC) 61400-1 extreme loading condition controls design (i.e. fatigue loading condition is not considered) 3) extreme loads are obtained from manufacturer provided structural load document that satisfies loading cases outlined in IEC 61400-1 4) wind forces on the tower are calculated in accordance with IEC 61400-1 5) optimization variables are continuous. The sum of the tower material and fabrication cost and the total foundation cost is taken as the objective function. Important conclusions from this work include: 1) optimization concepts and Microsoft Excel's optimization capabilities can be used to obtain reasonable conceptual level designs and cost estimates 2) detailed designs and cost estimates could be achieved using a solver capable of handling discrete optimization problems 3) considering the tower and foundation as an integral system results in a more expensive, but safer, design 4) for the assumed parameter values, the constraint on the tower's natural frequency was found to control the tower design and the bearing capacity constraint was found to control the foundation design 5) relaxing or tightening the limit on the natural frequency will result in the greatest benefit or penalty, respectively, on the optimum solution.
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Bittnerová, Lucie. "Bolt Tower Dolní Vítkovice - stavebně technologický projekt." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265548.
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The diploma thesis is dealing with selected parts of construction technology project of extension Vysoká pec no. 1 in Ostrava – Vítkovice. This thesis contains detailed elaboration of technological specifications for the construction of structural steel superstructure. For this phase is treated with a draft of mechanical report, inspection and test plan, dealing with traffic routes and itemized budget. There is also processed a proposal of building equipment which is the same for the entire implementation extension of Vysoká pec, a situation of building equipment, technical report of the object, the timetable for the entire project, ecology, health and safety.
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Ryan, Bona. "Finite Element Modelling and Parametric Studies of Semi-Closed Thin-Walled Steel Polygonal Columns - Application on Steel Lattice Towers for Wind Turbines." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-62064.
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The trend of structural engineering in the recent years is toward the use of lighter and moreeconomical structural elements. In steel construction, peculiarly, thin-walled structural elements arebecoming more popular and have a growing importance. Improved techniques in a manufacturing ofthin-walled elements have led to increased competitiveness of such products in the buildingapplications. Some examples of such structural element can be found in everyday life in form ofcolumns, studs, roofing trusses, and light-weight frames. However, the use of slender profiles and acomplex cross sections shape lead to requirements to study instability phenomenon in a form of local,distortional, flexural, torsional and coupled instability. Such complex structural behavior is inevitablyaccompanied by demand to improve calculation methods and design provisions. In this thesis, aninnovative solution of structural element composed of thin-walled plates is proposed for theapplication on lattice support structure of wind turbine.Thin-walled cold-formed profiles are steel products usually made from cold rolled coils and folded inthe second step. In this way, only open profiles can be produced. The predominant problem of theopen cross-section is the excessive torsional effect caused by the non-coincidence between the shearcenter and mass center, and a poor torsional resistance. A better response is possible with closed crosssections, but such profiles could not be produced by the folding. The solution is to make semi-closedsection by assembling them into polygonal profiles with mechanical fasteners, as presented in thisthesis.Objective of this work is to study the proposed structural sections in design situation and toinvestigate possible design models. The expected structural behavior of the column is a mixturebetween the open and closed cross-section. These cases will be investigated through numerical study.In this thesis presented a comprehensive parametric study on the ultimate strength of proposed coldformedsteel columns using the Finite Element package ABAQUS. FE models were first developedfor columns by using automation that was made through MATLAB and Python script. The bucklingand non-linear FE study was done for the investigation of local (L), distortional (D) and global (G)possible buckling failures and ultimate resistance, respectively. Modelling issues such as boundaryconditions, meshing, initial imperfections, material models, and non-linear solution controls in FEAwere also addressed.The parametric study involved series of profiles of built-up polygonal cross-section types with variedthickness (t), number of corners (n), diameter (d), slenderness (slend), yield strength (fy), number ofpoints along corner radii (np), extension lip length (lext), gusset plate thickness (tg), member length (l),and density of fasteners (s/d ratio), loaded in compression and bending moment. The bending momentoccurs as the effect of forces acting on the connection. The purpose of this analysis is to study thecritical load, cross-sectional behavior, influence of the amplitude of initial imperfections on theultimate load, and influence of each parameter used in the analysis through Full Factorial Design.
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Hanáčík, Jan. "Rozhledna Vršek nad Zlínem." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227754.
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This thesis deals with the design and assessment of the load-bearing structure of the lookout tower. The tower is 37.45 m high with the layout in the shape of a regular octagon. The object is located within the city of Zlín. The project is provisionally drawn in two variants. Hand-static calculation, drawings and engineering report is processed only for one variant. The variants differ in the structure of staircase. The thesis is drawn up pursuant to the standards of ČSN EN.
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Prokop, Miroslav. "Rozhledna v Beskydech." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409842.
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This master thesis deals with the design of load-bearing capacity of the observation tower in Besky-dy. The material used in main column is steel S355. The main column is a circular hollow construc-tion with diameter of 2,2 m. Inside the column is located a double spiral staircase. The upper part of observation tower simulates shape of treetop by rip column. It is made of glue laminated timber GL24h. The tower has four platforms of hexagon shape. The largest platform is 12,2m wide. The height of struction is 37,5 m. Internal forces have been calculated in software RFEM and based that the structural assessment has been made. The thesis is drawn up pursuant to the standards of ČSN EN.
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Gábor, Lukáš. "Rozhledna." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265302.
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The contents of this graduation thesis is design and assessment of the load-bearing structure of the observation tower situated between the village of Horni Lhota and Provodov. The construction was designed as a steel structure in two variants. Type A is cuboid shape with a side lenght ground plan 6,8 m and height of 37,7 m. Type B is an hourglass shape with a height of 39 m. Ground plan is a regular octagon shape with variable diameter. Detailed static calculation and drawing documentation was processed only for option B.
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Hájek, Ondřej. "Teleskopická věž samojízdné vrtné soupravy." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-318733.
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The thesis deals with the design of the drilling rig tower. The goal of the diploma thesis, which is created in cooperation with MND, a.s., is to design a steel structure. Then perform a load analysis. Further, to perform a structural analysis using the Finite Element Method and to optimize the design.
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Komárek, Ondřej. "Rozhledna v Brně Kohoutovicích." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392064.
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The main aim of my master´s thesis was to design a load-bearing steel structure of the lookout tower situated in Brno-Kohoutovice. The height of the load-bearing structure is 35.5 m. My design comprises two different engineering solutions. Solution A is a lattice space frame whereas Solution B works with continuous columns with vertical bracing. For further development, Solution A has been chosen. The proposed structural material is the S355 steel. My thesis includes an engineering report, a statics analysis and drawing documentation.
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Uherek, Jan. "Statická a dynamická analýzy ocelové konstrukce." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409745.
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The thesis deals with a description and a static and dynamic analysis for an existing construction of lookout tower. The steel watchtower is located in Město Albrechtice and is made up of two lattice towers connected by a bridge. Main point was to create calculation models for the purpose of dynamic and static analysis, in the software SCIA Engineer 19.1, which is based on the principle of finite element method. Attention was paid to load created by winds according to Eurocode 1 and Eurocode 3, glaze and rime ice load and dynamic coefficient calculation. The thesis also includes an assesment of selected parts of the construction according to Eurocodes.
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Kábrt, Michal. "Ocelová rozhledna." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-372095.
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The aim of the diploma thesis was to make a structural design of steel-load-carrying structure of steel lookout tower, in the grounds of domestic brewery in Humpolec. Lookout tower will be part of newly built centre for customers of the brewery. The layout and shape of the load-carrying structure of steel lookout tower follow the brewery chimney with height of 32.7 m with circular ground plan and outside diameter of 3.5 m in the heel and 2.3 m at the top. The chimney is independent of the construction of the lookout tower. The ground plan and dimensions of the lookout tower were considered taking into account the required spacing of the structure from adjacent buildings and ensuring sufficient dimensions for the required passage between the future lookout tower and the existing building of the boiler room. RFEM was used for calculation internal forces and assessment on individual structural elements, according to the valid Eurocodes.
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Kováčová, Kristýna. "Vyhlídková věž v oblasti Brdy." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392127.
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The subjekt of this thesis is a design of a viewing tower located in the area of Brdy. The structure has been created as a 3D model, the internal forces have been calculated with the use o finite element method in a structural engineering software Scia Engineer 15.1. Based on the knowledge of theses forces the design of the structural systems has been done. The materials used on this construction are glued laminated timber and steel. The height of the tower is 25,725 m. The floor plan is a shape of a circle and fluctuating smaller with the gaining height. The main structural systém consists of 8 curved posts which are radiály situated on the circular floor plan. The tower has 3 observational platforms.
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Frisk, Carlman Joel. "Äventyrstorn : En undersökning av konstruktionslösningar och material." Thesis, Mittuniversitetet, Avdelningen för ekoteknik och hållbart byggande, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-35529.
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Deep Wild är ett företag som bland annat specialiserar sig på produktutveckling och byggande av äventyrsanläggningar. Kunder till företaget har efterfrågat ett typ av äventyrstorn som det är möjligt att åka zipline från samt utföra andra aktiviteter såsom klättring på. Då Deep Wild inte har egen kompetens gällande dimensionering och projektering av denna typ av torn har en förfrågan skickats ut till studenter för att se om det fanns intresse att ta fram en lösning på utförandet. Syftet med arbetet är att undersöka hur ett äventyrstorn som detta kan konstrueras och ta fram en lösning på utförandet. Tornet dimensioneras enligt gällande Eurokoder. De laster som genereras av specialutrustningen tornet förses med finns i Svensk Standard. Två lösningar på möjliga utföranden tas fram, ett med alla bärande delar i stål och ett med lämpliga bärande delar i trä. Dessa jämförs sedan med hänsyn till lämplighet. Det visar sig att det finns många fördelar med att bygga tornet med enbart stålprofiler. Med stål som material kan alla bärande delar köpas ur det lagerförda sortiment som erbjuds på marknaden. Med trä finns inga lagerförda dimensioner att tillgå för de laster som uppstår. Vid de knutpunkter som dimensionerats visar det sig att de utförda i stål enkelt kan utföras så att de har mycket god säkerhetsmarginal. Knutpunkterna i träkonstruktionen klarar de dimensionerande lasterna endast med små marginaler. Genom att mer specialanpassa utseendet hos konstruktionen och dess verkningssätt så kan möjligtvis utförandet i trä gynnas. En prisjämförelse mellan de två materialen visar att skillnaden i materialpris är försumbar i sammanhanget. Två alternativa stabiliseringssystem undersöks för tornet. Det ena är att staga med en fackverkskonstruktion som använder sig av dragna stålstänger och tryckta strävor av respektive utförandematerial. Det andra är att staga tornet genom skivverkan i klätterväggen som uppförs på tornets ena sida. Skivverkan har sina fördelar då det möjliggör tryckta strävor på olika höjd i tornet. Fackverkskonstruktionen är dock att rekommendera då denna kan dimensioneras att ta avsevärt högre laster. Det naturliga nästa steget i arbetet ligger i att ta fram ett förfrågningsunderlag tillräckligt komplett för att kalkyleras.Deep Wild is an adventure company which specializes in product development among other things. Customers of the company have been asking for a tower from which it’s possible to exercise different kinds of adventure activities, such as ziplining and climbing. Deep Wild doesn’t have in house experience from constructing supporting structures that are not directly related to the special equipment used to exercise these activities. Therefore students have been asked to find a solution on how to construct a tower like this. The purpose of this study is to investigate how an adventure tower can be constructed. The tower is structurally designed using Eurocodes and the loads generated from the activities exercised appear in European Standard. Two possible solutions for the construction is developed, one with all supporting parts in steel and one with selected supporting parts in wood. These are then compared to each other with regard to their performance. The results show that there are many advantages using only steel profiles. All steel profiles required for the construction can be bought out of existing stock from producers. To use wooden profiles it is required to place orders on standard dimensions that are not part of the producers existing stock. The joints designed shows that using steel profiles these can easily be designed to provide a high safety margin. The joints designed using steel connectors to wooden profiles provides enough support only with small safety margins. By adjusting the design of the towers supporting system the use of wooden profiles could possibly be benefitted. A price comparison based on the price of material shows that the difference between laminated timber and steel in this construction is negligible. Two alternative ways of stabilizing the tower have been investigated. One with tensioned steel bracing and compressed bracing using the different construction materials. The other one using wall diaphragms on the side of the tower clad with climbing wall. The wall diaphragms method has its advantages because it makes it possible to place compressed bracings on different heights in the tower. The system with tensioned bracings can take higher loads and provide better safety margins and is therefore the recommended way of stabilizing this tower. The next step of this project is to provide complete enough material to calculate the cost of constructing.
Betyg 2018-06-05
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Pojezný, Tomáš. "Vyhlídková věž v Beskydech." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226644.
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This work contains structural design and static assessment of the viewing tower in Beskydy. Construction is shaped like fir cone and it is made from glued laminated profiles and steel square tubes. Joints are realized from steel structural elements. Ground plan is regular octagon with external diameter changeable from 7,3 m to 9,3 m. Tower has five viewing platforms. Total height of construction is 27,5 m. For designed structure is made detailed static assessment and drawing documentation.
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Kamrádová, Michaela. "Lesní vyhlídková věž v Beskydech." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-372142.
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Topic of this Master's Thesis is a design and a statical evalution of a load bearing structure of an observation tower in Beskydy mountains. Ground plan of this structure is in a shape of a nonagon with a non-roofed interior space. Height of the observation tower is 38,5 m, the shape of a ground plan doesn't change with a radius of a circumscribed circle of 12 m. The structure is designed from glued laminated timber, solid wood and steel. Columns bear horizontal beams and their stiffness is ensured by horizontal and inclined reinforcing beams. Main load bearing columns, upper and lower beams are designed from glued laminated timber GL24h. Upper beams and beams of a gallery are designed from glued laminated timber GL36h. Horizontal stiffener is designed from solid wood C24. Central column, inclined beams, stairway, water slide cantilevers, rod and central rod are designed from steel of a strength class S235. Cantilever for gallery is designed from steel of a strength class S355. Connections are designed from steel elements. Statical evaluation, technical report and construction drawing are included
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Virág, Patrik. "Nosná ocelová konstrukce rozhledny." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240109.
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The subject of the diploma thesis is design and structural analysis of loadbearing steel structure of observation tower, which is located southeast of Černá Hora, township Blansko. The design is processed in two options. Parts of the thesis are engineering report, structural design report for both of the options and graphical documentation in specified range. The structure’s height is 25.3 m and maximal ground plan dimension is 6 x 6 m. Steel grade S355 was chosen as main material. The sub-objectives of the structural analysis are load effects calculations (permanent load, imposed load and climatic load), entering of loads to the calculation model and calculation of internal forces and deformations. An assessment of the supporting elements and selected joints is also included. There are dynamic design features considered in the calculation. All calculations were performed in accordance with valid ČSN EN standards.
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Kadlček, Dan. "Konstrukce rozhledny v Javorníkách." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227842.
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The aim of diploma thesis is design and assessment of bearing structure of viewing tower on the mountain Makyta in Javorníky, which is designed from timber and steel. The shape of construction is variable of its height. Diameter of octagonal platform at ground level is 12 m, in the middle of construction is 7,7 m and on the top of the construction is 8,7 m. Viewing tower has 5 viewing platforms – the highest one is covered by roof. Wooden elements are designed from glued-laminated GL24h timber, steel elements are designed from steel of S235 grade. Main support elements of structure are wooden rectangular outer columns and steel circle center column. Total height of construction is 31 m. Static analysis has been accomplished by student version of the SCIA Engineer 2014 software.
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Turková, Martina. "Rozhledna na jižní Moravě." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240264.
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This master’s thesis deals with the design and static assessment of a lookout tower in The Brno Zoological Garden situated on the hill called Mniší hora. The construction of the lookout tower is meant to be of a circular ground plan and its overall height is 31 m. The construction was designed in two variants. For both methods was used a combination of steel and solid or glued laminated timber. For detailed elaboration was selected only one variant. The lookout tower was assessed in a Scia Engineer 15.1 software.
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Hu, Yu. "Improvement of the structural response of steel tubular wind turbine towers by means of stiffeners." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/6227/.
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In the thesis the structural response of steel tubular wind turbine towers with various design configurations is analysed using FEM modelling. First, a structural response simulation model was validated by comparison with the existing experimental data. This was then followed with a mesh density sensitivity analysis to obtain the optimum element size. Based on this outcome, towers of various heights between 50-250m are considered and investigated with three different design options as follows: (i) thick walled tower with internal horizontal stiffening rings, (ii) thick walled tower without stiffening rings and (iii) thin walled tower with stiffening rings. Based on this analysis, weight reduction ratios are examined in relation to the horizontal sway and von Mises stress increase ratios in order to identify a more efficient design approach between reducing the wall thickness and adopting internal stiffeners. All studied design solutions satisfy the strength and serviceability requirements as specified by the design codes of practice.
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Folster, Kaylee. "Influence of geometry on the dynamic behaviour of steel tubular towers for onshore wind turbines." Master's thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/25282.
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South Africa has recently experienced challenges regarding electricity consumption and availability. As part of the country's Integrated Resource Plan, these challenges are to be addressed. This involves a 20 year plan which aims to increase electricity supply capacity as well as reduce the reliance on coal power as part of the global trend to become more environmentally friendly. Wind power, specifically, is to account for a large portion of the renewable energy that is expected to become available by 2030. This results in the need for the understanding of wind turbine design by South African engineers. The dynamic analysis of wind turbine structures, is of particular interest to Civil Engineers. Wind turbine towers are recently of the monopole or tubular type tower, predominantly constructed of either concrete or steel or a combination of both. Steel tubular towers above a height of 80m are generally not recommended for wind turbines owing to cost concerns as well as difficulties in meeting dynamic behaviour requirements. Concrete towers and steel-concrete hybrid towers are recommended for this height regime. The aim of this study was to assess the prospective use of steel tubular towers of varying geometric shape for wind turbines with tower heights of 80m or greater. The study focussed on the analysis of natural frequency and assessing the applicability of steel tubular towers of geometric shapes that have not been previously explored or reported. The turbine of choice for this study was the Vestas V112 3MW type as this is one of the most commonly used and more efficient turbines for towers of this height regime. The results of this study showed that steel monopole towers of heights of 80m and more are still viable options for wind turbine towers. Various geometric tower cases of heights varying from 80m to 120m, produced acceptable fundamental natural frequencies within the allowable frequency range for a Vestas V112 3MW turbine.
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Vrbka, Jan. "Vyhlídková věž v oblasti jihovýchodní Moravy." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226913.
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he master’s thesis consists of a case study of an observation tower design made of glue laminated timber and steel. There are two different tower shapes of anchored or free standing tower and these towers are compared. One of the design is chosen and elaborated into final detailing. A short review of main issues bound with the observation towers is given. The review deals mainly with loading (mainly priniples wind loads are analised) and evaluating of towers (ultimate limit states, service limit states and acceleration comfort). The height of final construction is up to 60m. The design is formed by a space lattice structure made of glue laminated timber and steel members of different class. The members are fastened mainly by means of dowel joints with slotted-in-plates . There is a light steel stairway inserted into the main structure.
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Heistermann, Christine. "Behaviour of pretensioned bolts in friction connections : towards the use of higher strength steels in wind towers." Licentiate thesis, Luleå tekniska universitet, Byggkonstruktion och -produktion, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17672.
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During recent years wind energy has established as an alternative to commonenergy sources. To advance its competitiveness, the costs for the constructionof a wind tower have to be reduced. One possible option is the use of frictiongrip joints instead of flange connections to join various tower segments in atubular steel tower. Additionally, the time necessary for installation andmaintenance of the bolts in these connections can be decreased, not only forimplementation in tubular towers but also in lattice towers.Four different bolt types have been investigated with respect to the ease ofinstallation and maintenance on the one hand and structural applicability on theother hand. The latter one is mainly defined by the behaviour of the pretensionforce in the bolts. Various influences on the reduction of clamping force areexperimentally checked, such as the type and thickness of coating, thethickness of the clamping package and external loading.The slip factor, which plays an important role in friction connections, isexperimentally achieved in a test on a double shear lap joint. The experiment isthoroughly examined by a finite element analysis, which models the interactionbetween bolts and plates.In various numerical analyses the influence of steel grade and possibleassembling tolerances on the resistance of a friction joint is investigated bothfor single and double shear lap joints.Shortages of EN 1993 parts 1-8 and 1-12 for the use of slip critical joints areidentified.På senare år har vindenergi blivit ett allt vanligare alternativ till de mertraditionella energikällorna. För att ytterligare stärka konkurrenskraftenbehöver installationskostnaden för vindkraftverken minskas. Ett sätt att göradetta är att använda friktionsförband istället för att sammanfoga flänsarna hosde olika segmenten i vindkraftverk uppbyggda av stålrör. Man kan dessutomminska den erforderliga tiden för att montera och underhålla skruvarna i dessaförband, vilket inte bara gäller för rörkonstruktioner utan även förvindkraftverk av fackverkstyp.Fyra olika sorters skruvar har undersökts, å ena sidan avseende hur enkla de äratt montera och underhålla, å andra sidan avseende den strukturellatillämpligheten. Den senare beror huvudsakligen på beteendet hosförspänningskraften i skruvarna. Olika sorters påverkan påfastspänningskraften har undersökts experimentellt, exempelvis ytskiktenstjocklek, klämlängden samt den påförda yttre lasten.Friktionskoefficienten vid glidning, som har en viktig roll i friktionsförband,har erhållits experimentellt genom försök med ett tvåskärigt skjuvförband.Försöken har utvärderats noga med FE-analyser, där interaktionen mellanskruvar och plattor har modellerats.Inverkan av vald stålsort samt utförandetoleranser har undersökts genomnumeriska analyser för både enskäriga och tvåskäriga skjuvförband.Brister i EN-1993 del 1-8 och 1-12 har identifierats vid användning av förbandsom är känsliga för glidning
Godkänd; 2011; 20110506 (chrott); LICENTIATSEMINARIUM Ämnesområde: Stålbyggnad/Steel Structures Examinator: Professor Milan Veljkovic, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Diskutant: Professor Carlos Rebelo, University of Coimbra, Portugal Tid: Fredag den 10 juni 2011 kl 10.00 Plats: F1031, Luleå tekniska universitet
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Beşoğul, Ercan Supervisor :. Dikmen Toker İrem. "Reasons of delays in steel construction projects : an application of a delay analysis methodology \h [Electronic resource] / \c Ercan Beşoğul, Supervisor Assoc. Prof. Dr. İrem Dikmen Toker." Ankara : METU, 2006. http://etd.lib.metu.edu.tr/upload/12607159/index.pdf.
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SANTOS, Ives José Adriano dos. "Análise dinâmica de suportes para antenas em torres metálicas para telecomunicações." Universidade Federal de Pernambuco, 2015. https://repositorio.ufpe.br/handle/123456789/18079.
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Na última década, o crescimento da telefonia celular no Brasil venceu os limites das grandes capitais, levando a rede a cobrir municípios antes desprovidos de tal tecnologia. A transmissão do sinal pode ocorrer de diversas formas, mas, de fato, a mais comumente utilizada é por meio de antenas sustentadas por torres metálicas. Na prática, as antenas são instaladas em qualquer momento após a montagem da torre, mesmo anos após sua construção, sem qualquer verificação estrutural e, por vezes, excedendo a capacidade de carga nominal. Além disso, na maioria dos casos, não são levados em conta certos cuidados com relação ao posicionamento de suportes e das próprias antenas. Portanto, é comum encontrarmos antenas instaladas de forma inadequada, sendo colocadas fora da silhueta da torre. Este posicionamento, aliado com a ação dinâmica ocasionada pelo vento, pode trazer problemas graves à estrutura. Neste trabalho, são apresentados dois casos reais de torres metálicas que sofreram danos estruturais devido ao problema em questão. Este trabalho tem como principal objetivo apresentar uma solução de amortecimento para as vibrações causadas pelo vento em antenas para telecomunicações. A proposta visa utilizar elastômeros, como o Neoprene, entre a cantoneira do montante e as abraçadeiras dos suportes, reduzindo assim o período de vibração e, consequentemente, os efeitos da fadiga.
In the last decade, the growth of mobile telephony in Brazil won the boundaries of the great capitals, leading the network to cover cities before devoid of such technology. The signal transmission can occur in various ways, but, in fact, the most commonly used is through antennas supported by steel towers. In practice, the antennas are installed at any time after assembly of the tower, even years after its construction, without any structural verification and sometimes exceeding the rated load capacity. Moreover, in most cases, care is not taken into account in relation to the positioning brackets and their antennas. Therefore, it is common to find antennas installed improperly, being placed outside the tower silhouette. This positioning, combined with dynamic action brought by the wind, can bring serious problems to the structure. In this work, we present two real cases of metal towers that have suffered structural damage due to the problem at hand. The objective of this work is to present a solution for damping the vibrations caused by the wind in telecommunications antennas. The proposal to use elastomers, such as neoprene, between the bracket and the tower column, thus reducing the vibration period and, consequently, the effects of fatigue.
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Jurák, Vítězslav. "Novostavba farního kostela v Brně-Líšni." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227828.
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This diploma thesis, called „Parish church, Brno-Líšeň“, is compiled as documentation for building construction. There is one complex building situated in slope. Therefore it consists of one partly underground floor and first floor. It is divided into three sections. Central part is designed as round-shaped body of the church with tower in the southern part of the church. Shed roof has an angle of 7° for body and an angle of 13° for tower. From the western side there is an administrative area connected to the church and from eastern side there is a community area which is supposed to be used as residential premises. Roof of both these parts is constructed as flat vegetative roof. Structural design is systemic, Velox. Foundation construction combines concrete and ferro-concrete belts and footing.
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Prithiraj, Alicia. "Corrosion behaviour of ferrous and non-ferrous alloys exposed to sulphate - reducing bacteria in industrial heat exchangers." Thesis, Vaal University of Technology, 2018. http://hdl.handle.net/10352/433.
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M.Tech. (Department of Chemical Engineering, Faculty of Engineering and Technology), Vaal University of TechnologyCorrosion responses of some carbon steels, stainless steel and copper alloys in the presence of a culture of bacteria (referred to as SRB-Sulphate-reducing bacteria) found in industrial heat exchangers, was studied to recommend best alloys under this service condition, with techno-economic consideration. Water from cooling towers in three plants in a petrochemical processing complex were analysed for SRB presence. Two of the water samples showed positive indication of SRB presence. The mixed cultures obtained from plant one were grown in prepared media and incubated at 35 °C for 18 days. Potentiodynamic polarisation studies in anaerobic conditions were done on the selected alloys in aqueous media with and without the grown SRB. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were then used to study the corrosion morphology and corrosion products formation. The voltamograms show higher icorr for alloys under the SRB compared to the control media, indicating the SRB indeed increased the corrosion rates. The surface analysis showed pitting on steel alloy ASTM A106-B. Localised attack to the grain boundaries on a selective area, was seen on ASTM A516-70 dislodging the grains, and intergranular corrosion was seen throughout the exposed area of ASTM A179. Copper alloys showed pitting on ASTM B111 grade C71500 (70-30), and denickelification on ASTM B111 grade C70600 (90-10), and is a good alternative material for use apart from carbon steel alloys, recording a low corrosion rate of 0.05 mm/year. The EDS analysis supported the findings showing higher weight percent of iron and sulphur on surface of the alloys after exposure to the SRB media. This implies that the presence of the sulphur ion indeed increased the corrosion rate. ASTM A516-70 carbon steel was chosen as a suitable alternative material to the stainless steel in this environment. The Tafel plot recorded a corrosion rate of 1.08 mm/year for ASTM A516-70 when exposed to SRB media.
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Peštálová, Lucie. "Kraví hora - rodinné stříbro VUT." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-400054.
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The subject of the diploma thesis is to design a project study and a building program that would become a compromise between the requirements of the city of Brno and BUT in the area of Kraví hora in the Brno city center. The city of Brno would like to transform the area into a public park. But BUT considers it as its "family silver" because they realize its extraordinary value. Options of a constructions are really limited because of many area regulations. My proposal counts on the demolition of all existing buildings in the area, respects property area relations , protection zone, continuity with existing traffic roads, height regulation, imaginary raster of surrounding buildings, slope of terrain and orientation to the cardinal points. My suggest represents a study of five groups of objects which creating a rectangular raster. As a compromise solution, I chose the presentation and promotional areas of the individual faculties of BUT for the content of the buildings. Faculties have spaces for hobby groups for the public comprise all age groups included. I also designed the BUT Museum of History, a multimedia hall, a cafeteria, studios, a student leisure center and an observation tower with a climbing wall.
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Oliveira, Marcel Isandro Ribeiro de. "Análise estrutural de torres de transmissão de energia submetidas aos efeitos dinâmicos induzidos pelo vento." Universidade do Estado do Rio de Janeiro, 2006. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=417.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorNa prática corrente do projeto de torres de aço treliçadas utilizadas para suportar linhas de transmissão de energia elétrica, a avaliação do comportamento dinâmico das estruturas, de maneira geral, não é considerada. Contudo, o principal carregamento a ser considerado na análise estrutural das torres de transmissão de energia elétrica é produzido pelo vento, que atua de forma dinâmica sobre o sistema estrutural formado pelos cabos e pelas torres. Além disso, muitas estruturas desse tipo apresentam características dinâmicas desfavoráveis, o que as tornam mais vulneráveis a ação do vento.Tendo em vista que muitos acidentes envolvendo torres desse tipo ocorrem ainda que a velocidade de vento utilizada no projeto não tenha sido atingida, é possível que em muitos casos o colapso tenha sido governado pelas ações dinâmicas. Assim sendo, esse estudo tem por objetivo a utilização de uma metodologia de analise estrutural que possibilite uma avaliação mais completa acerca do comportamento das torres de transmissão de energia, considerando, obviamente, as características dinâmicas do sistema. Este trabalho de pesquisa utiliza um modelo de elementos finitos capaz de reproduzir com fidelidade o comportamento acoplado entre os cabos da linha de transmissão e estrutura quando submetidos aos carregamentos dinâmicos e não determinísticos produzidos pelo vento. O modelo tridimensional estudado é constituído por elementos finitos de pórtico e treliça espacial e considera o efeito de não-linearidade geométrica decorrente, principalmente, dos grandes deslocamentos sofridos pelos cabos e isoladores. O carregamento do vento é modelado como um processo aleatório a partir das suas propriedades estatísticas. Os resultados obtidos ao longo desse estudo mostram que a parcela dinâmica da resposta das estruturas pode ser determinante no seu comportamento. Nesse caso, a utilização de uma análise estrutural estática pode resultar no mau dimensionamento das torres e, conseqüentemente, em possíveis acidentes.
In the current design process of steel latticed towers used to support electrical transmission lines, the structures dynamic behaviour is not considered. However, the main loading to be taken into account in the electrical transmission line towers structural analysis is produced by the wind, which acts dynamically over the structural system composed by towers and cables. In addition, its not uncommon for slender towers to present disadvantageous dynamic properties, making them vulnerable to the wind action. Considering that many accidents associated to this kind of structure occur even for wind velocities below that specified in the design process, its possible that most of these accidents have been produced by dynamic actions. Therefore, this study aims to develop a structural analysis method that allows for a more accurate evaluation of the electrical transmission towers behaviour, considering its intrinsic dynamic effects. This study proposed the use of a finite element model that can accurately simulate the coupled behaviour between the transmission line cables and the suspension structures when subjected to the dynamic random loading produced by the wind. The proposed three-dimensional model is composed by beam and truss spatial finite elements and accounts for the geometric non-linearity effects produced by the large displacements associated to the line cables and insulators. The wind loading is modelled as a random process based on its statistical properties. Results obtained throughout this study have indicated that the dynamic response can be very meaningful for the system structural behaviour. In this case, the use of a static structural analysis can lead to a non-trustable design of the towers and, consequently, to potential structural failures.
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Guimarães, Eduardo Henrique. "Análise do comportamento de torres de aço estaiadas sob a ação do vento." Universidade Federal de Uberlândia, 2008. https://repositorio.ufu.br/handle/123456789/14812.
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Conselho Nacional de Desenvolvimento Científico e TecnológicoThe main objective of this work is to analyze the behavior of guyed towers of different heights, subject to the following solicitations: wind loads, dead weight, and prestress of the stays. The study was done in order to better understand the influence of some static and dynamic parameters in these structures. Guyed towers are structures that are utilized in several applications, such as, for instance, transmission towers. Besides determining the best quantity, disposition, and inclination angle of the stays for these systems, it was verified the influence of different methods used to calculate wind loads in the following results: Von Mises stresses, forces on the stays, and the resulting displacement. The methods used were the ones mentioned in the Brazilian Standards NBR6123/1988, and in order to calculate the wind loads acting on the tower, algorithms in MATLAB® were implemented. The tower masts were designed using the admissible stress method. For the three-dimensional models in finite elements and their analysis, were elaborated APDLs (ANSYS Parametric Design Language) the structural systems, in such away to optimize the time spent on the modeling and to reduce possible source of uncertainty. The results analysis consists in evaluating the sensitivity of the design variables in terms of: Von Mises stresses, forces on the stays, and resulting displacements. Also, modal analyses were done to verify the influence of the support conditions on the base of the mast on the natural frequencies of the structure. The obtained results showed that the inclination angle of the stays with respect to the mast can be reduced, propitiating an area reduction occupied by the tower. It was also observed, that the resulting displacements of these structures are more sensitive to the studied parameters than the stresses and the forces on the stays. The studies done and the obtained results show a better understanding of the structural and the dynamic behaviors of this type of structure.
Este trabalho tem por objetivo analisar o comportamento de torres estaiadas de diferentes alturas. Estas estão sujeitas as solicitações de vento, peso próprio e pré-tensão nos estais. Foi feito um estudo com a finalidade de conhecer a influência de determinados parâmetros na resposta estática e dinâmica dessas estruturas. Torres estaiadas são estruturas utilizadas em diversas aplicações, como por exemplo, em torres de transmissão. Além, de determinar a quantidade, disposição e ângulo de inclinação ótimos dos estais para esses sistemas, verificouse ainda, a influência dos modelos de cálculo das solicitações de vento, sugeridos pela NBR 6123/1988, nas tensões de Von Mises, esforços nos estais e deslocamentos resultantes nas estruturas. Os mastros das torres foram dimensionados utilizando o método das tensões admissíveis. As solicitações advindas da atuação do vento nas torres foram obtidas através de algoritmos implementados em MATLAB®, utilizando os vários modelos de cálculo apresentados na norma brasileira. Para modelagem tridimensional em elementos finitos e realização das análises, foram elaboradas rotinas em linguagem APDLs (ANSYS Parametric Design Language) para os sistemas estruturais, de maneira a parametrizar os modelos e otimizar o tempo gasto na modelagem. Foi realizada uma análise para avaliar a sensibilidade de determinadas variáveis de projeto tais como, quantidade, posicionamento e ângulo de inclinação dos estais, em termos de tensões de Von Mises, esforços nos estais e deslocamentos resultantes. Ademais, foram realizadas análises modais para verificar a influência das condições de contorno da base do mastro sobre as freqüências naturais da estrutura. Os resultados obtidos mostraram que o ângulo de inclinação dos estais com relação ao mastro pode ser reduzido, propiciando uma redução da área ocupada pela torre. Observouse também, que os deslocamentos resultantes dessas estruturas são mais sensíveis aos parâmetros estudados do que as tensões e os esforços nos estais. Os estudos realizados e os resultados obtidos levam a uma melhor compreensão do comportamento estrutural e dinâmico desse tipo de estrutura.
Mestre em Engenharia Mecânica
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HAO, HUANG YI, and 黃逸豪. "The Analysis of High Steel Tower Under Along-Wind." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/22587776209995923472.
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碩士中原大學
土木工程研究所
86
The main purpose of this thesis is to discuss the response of high steel tower under along-wind load ,which including sidesway,base-moment ,and the type of vibration. According to the development of communication in the recently years , and the antennasare always putted on high tower ,so the safety of high steel tower is worthy to study. The deformation and stress of high steel tower are about eighty to ninety percents coming with wind forces,especially are the along-wind forces. Besides, the cross-wind, which makes the vibration of tower, is perpendicular to the along-wind. The sidesway , bottom shear , base-moment of tower which due to along-wind force are the important parameter in design. The main contents of this thesis is to research the influence oftower used for micro-wave due to along-wind force and the analysis of structure.
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Figueiredo, Guilherme Gandolfi. "Structural behaviour of hibrid lattice-tubular steel wind tower." Master's thesis, 2013. http://hdl.handle.net/10316/38482.
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Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e Tecnologia da Universidade de CoimbraO principal objectivo da presente proposta consiste em desenvolver uma nova solução híbrida em aço para torres de turbinas eólicas de multi - megawatt, utilizando uma estrutura em aço treliçada que servirá de suporte a parte superior da torre de secção tubular. A utilização de torres com secção tubular em aço na parte superior deve-se ao facto de aproveitar o conhecimento já estabelecido e optimizado dessa tecnologia, com diâmetros apropriados para serem transportados em estradas públicas. A parte treliçada da torre introduz a possibilidade de torres mais altas (além de seu custo de produção ser mais baixo) e utiliza um novo tipo de sistema de montagem para a secção tubular, através de um processo de deslizamento, por meio de macacos hidráulicos evitando assim a necessidade da utilização de grandes guindastes. Importantes vantagens deste conceito são: (i) velocidade de construção, evitando o uso de grandes guindastes ou torres de elevação e da sua disponibilidade , (ii) o uso da tecnologia de torres de secção tubular já conhecida dos construtores de torres e perfeitamente estabelecida no mercado , (iii) optimização das fundações e da seção transversal da torre ao longo de toda a sua altura
The main objective of this proposal is to develop a new hybrid steel solution for multimegawatt wind turbine towers, using a steel lattice structure supporting a steel tubular upper part of the tower. The use of a tubular part takes advantage of the well-known and optimized technology of tubular steel towers with diameters suitable to be transported on public roads. The lattice part of the tower introduces the possibility of higher towers (than are economically feasible in tubular construction) and facilitates a new type of erection system for the tubular section by a sliding procedure, using hydraulics jacks, thus avoiding the need for very large cranes. Important advantages of this concept are: (i) speed of construction, avoiding the use of expensive and availability-dependent large cranes or lifting towers, (ii) use of technology already established for tubular towers, (iii) optimization of foundation and tower cross section along height
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Liao, Pei-Chi, and 廖珮琦. "A Case Study of Electric Steel Tower on Engineering Project." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/44242801885066748007.
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碩士國立臺灣科技大學
管理研究所
97
The electric steel tower industry was researched in this study. Then through case study, by the project management process, analyzing the engineering construction process of the electric steel tower, and introducing the planning, human resource, time, cost, quality, risk and evaluation of project management. Finally, according to the challenge of the project process, find out the problems and solutions. Hopefully, it would help the related industries of the electric steel tower in Taiwan.
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Hsun-chu, Fang, and 方循矩. "The Analysis of Stability by Wind of the High Steel Tower." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/87575806461752029970.
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碩士中原大學
土木工程研究所
86
The importance of the micro-wave communication becomes more obvious withthe improvement of the world. Signals are translate by the micro-waveincluding TV, Broadcast and Mobilephone et cetera. The micro-wave antenna tower is the base of the micro-wave communication. The micro-wave will beinterrupted because of the higher and higher buildings in the city. We need to build higher tower in order to rise the quality of the micro-wave communication. The behaviors of steel tower used for micro-wave is similar to the cantilever beam. It has obvious response by lateral loading. So the main load of the tower is wind and earthquake. Every year on the average, there were three typhoons visited Taiwan. So the effect of the wind is more than the earthquake. The main purpose of this thesis is to calculate the forces which cause by the along-wind and analyzes the stability of the whole structure. Finally, we check the stress ratio of each members by AISC(ASD) manual.
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Chung-I, Chiu, and 邱中一. "The Analysis of Tall Steel Latticed Tower under Cross-Wind Action." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/57243026422639969632.
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碩士中原大學
土木工程研究所
86
This paper primarily investigates the behaviors of tall steel latticed tower under cross-wind action in the atmospheric boundary layer.Acturally, wind tunnel experiments are normally carried out on highrise buildings for assurance of preliminary design. Structures such as tall microwave steel latticed towers conducted in a wind tunnel are necessary for the highrise trend and other special considerations.Features such as more slender, flexible and lightly-damped, make it obviously different from normal buildings in geometry and mechanical properties, so wind is an important point in elimating structural displacement responses and is susceptible to aeroelastic instability in cross-wind direction. Meanwhile, the formation and effects of lock-in phenomena is significant part of this paper.In order to examine the lock-in displacement of steel tower, with some simplified assumptions, emphasis is on dealing with predictive models and code formulas of circular cylinder for the early design stage. Finally, it''s intended to study and compare the test and calculating results, and to discuss their practicability.
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Pires, Pedro Miguel Rodrigues. "Design of concrete-steel transitions in a hybrid wind turbine tower." Master's thesis, 2013. http://hdl.handle.net/10316/38501.
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Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e Tecnologia da Universidade de CoimbraO crescimento exponencial da população mundial tem acentuado a necessidade de recursos disponíveis e o consumo energético. Como forma de responder a essa crescente procura e com o objectivo de preservar os recursos naturais existentes, a energia eólica apresenta-se como uma solução eficaz. A energia eólica é a fonte de energia com a maior taxa de crescimento, situando-se em cerca de 20% ao ano. O aumento da potência dos aerogeradores exige torres de maiores dimensões levando ao repensar de soluções e a procura de alternativas. Os elementos pré-fabricados de betão surgem como uma alternativa relativamente às torres metálicas. Soluções hibridas permitem aproveitar as vantagens de ambos os materiais conduzindo a soluções promissoras para grandes alturas. O peso dos segmentos de betão é cada vez mais um problema em torres de grandes dimensões. Estes elementos são construídos em apenas uma peça o que leva a soluções pesadas, de grandes dimensões e difícil transporte. O objectivo principal deste trabalho consiste no dimensionamento e comparação de diferentes soluções para os segmentos de transição numa torre híbrida de 122 metros com um sistema de pré-esforço pelo exterior. Foram estudadas e comparadas duas variações da transição tendo em conta aspectos como peso, dimensões, necessidades construtivas, armaduras e resistência a acções de fadiga. A primeira alternativa estudada consiste num segmento mais curto e a segunda num elemento mais esbelto sempre com o objectivo de reduzir o peso do elemento de transição. Inicialmente foi necessário definir completamente a geometria da flange, a posição e traçado dos cabos de pré-esforço. Foi realizado um cálculo detalhado das necessidades de pré-esforço e respectivas perdas. As quantidades de armaduras foram dimensionadas tendo em conta situações criticas tais como os efeitos de esforço transverso e torsão, controlo da fendilhação em betões jovens e os efeitos de forças radiais devido aos pontos de desvio do pré-esforço, foram também tidos em conta os efeitos das acções de fadiga
In recent years, the Earth has witnessed an exponential population growth demanding for more resources and energy. As a response to this need wind energy presents itself as an intelligent choice, a never ending source of energy with limited environmental impact, with its goal to preserve the earth’s depleting resources. Wind energy is the world´s fastest growing energy source increasing at an annual rate of 20%. The increasing generators capacity demands for higher towers with new solutions, new materials and new construction processes. Pre-fabricated concrete sections appeared as a good alternative to steel and hybrid solutions aim to take advantage of both materials leading to cheaper and better performing wind turbine towers. One current problem with high concrete towers is the weight of the segments. The top concrete segments have to be built as a single section, creating quite massive elements. The main objective of this work is to design and compare different solutions for concrete-steel transitions in a 122 m externally prestressed hybrid tower. Two different geometries for the top concrete segment were studied and compared with aspects such as weight of the segments, dimensions, production requirements, reinforcement amounts or fatigue damage taken into account. The first concrete segment variation is shorter than the typical ENERCON segments and the second is a thinner one, aiming at reducing the weight of the transition element. The design first steps consisted of the definition of the flange connection configuration and definition of the prestress tendons position. An extensive calculation of the prestress was performed with repercussions in every other element. The reinforcement of the segments was determined taking special focus to the effects of shear and torsion, early-age thermal crack width and the radial forces from the deviation points. The effects of fatigue damage on the structure were also taken into account
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Chang, Wen-Te, and 張文德. "Tower Crane Site Layout and Schedule Monitoring for Steel Structure Erection." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/94447997061094872841.
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碩士國立台灣工業技術學院
營建工程技術研究所
85
This research endeavor focuses on erection planning problems for tower crane in construction operations of steel structure. In this research, an automated erection planning system comprising of a Geographic Information System (GIS) integrated with a database management system (DBMS) was developed. This system improves the lifting pl?Scng efficiency by integrating spatial and thematic information into a single environment. Also, compared with current methods, the system significantly improves the computational effort and increases the data accuracy and consistency. Therefore, this study achieves the goal of developing an automated information system to enhance the erection planning for tower cranes.
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GAO, YUAN-LI, and 高元利. "Small suspension bridge construction quality control study- Swing-column Steel Bridge tower." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/98313436950472509248.
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碩士國立高雄應用科技大學
土木工程與防災科技研究所
102
In this thesis, based on three practical cases of swing-column suspension bridges, the quality control and nonlinear structural behavior during the construction stages of small-scale suspension bridges are studied and related domestic and foreign construction specifications are surveyed to investigate possible inspection standards for the construction of these bridges. The deflected shape of the swing-column suspension bridges during various construction stages are analyzed using SAP2000, and the analytical results are compared with the design values and the measured data obtained at the construction sites. The comparisons are used to examine the safety of the construction works. The results of this thesis can be applied for the quality control for the construction of small-scale suspension bridges in Taiwan.
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Lee, Chia-Yu, and 李佳諭. "An Investigation on Ultimate Capacity Analysis and Safety Assessment for Transmission Steel Tower." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/68948705578591607782.
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博士國立臺灣大學
土木工程學研究所
100
Almost all transmission installations are designed for overhead transmission, and transmission lines are linked by steel towers as their supports. Once a tower on the line is damaged or becomes unstable, a large-scale power failure will occur, and consequently huge economic losses may occur. Therefore the safety of steel towers strongly influences the reliability of power supply in transmission lines. In this paper, two different types of tower in Taiwan Power Company (TPC) will be studied and discussed, those are composed of suspension towers (Type B5), and strain towers (Type E5). Their dynamic characteristics, non-linear behavior, and ultimate capacity under wind force will be well studied. The firstly, cable models based on loading and sag condition analysis will be established, and the dynamic characteristics and reactions for cables under wind disturbance will be investigated. According to the specifications of TPC Standard Code, the applied loads on tower in the transverse, longitudinal, and vertical directions will be determined. The secondary, the towers will be analyzed linearly and nonlinearly by using Pseudo-elastic method and nonlinear static pushover analysis associated with SAP program. Finally, the ultimate lateral force, and ultimate drift can be determined. The results presented in this paper for the ultimate capacity of the towers with acceptable accuracy. In addition, our approach is based on the new techniques of Hilbert-Huang Transform (HHT), such as the Ensemble Empirical Mode Decomposition (EEMD), the Ensemble Hilbert Spectrum (EHSP), and the two-station HHT spectral ratio approach. This study is intended to identify the dynamic characteristics from the measured ambient vibration data for the tower, and from which the tower can be assessed to be sound, damaged or unstable from the spectrum appearance after analysis. The new techniques of HHT and nonlinear analysis method associated with pseudo-elastic approach and nonlinear static pushover analysis could be applied to carry out the dynamic characteristics and the ultimate capacity of the towers with acceptable accuracy. The results of this study would be valuable references for the advanced studies in improving design, safety assessment and health monitoring of the transmission towers in Taiwan.
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Long, Tser Lee, and 李榮哲. "The Design and Analysis of Standard Tall Steel Angles Tower with Micro-Wave Antennas." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/42613530914618608127.
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碩士中原大學
土木工程學系
87
The main purpose of this paper is to describe the ways to design the tall steel tower with micro - wave antennas. Also through the following literature, a series of angles unified and standardized steel towers with micro - wave antennas could be established. The steel towers with micro - wave antennas is designed as a flexible structure exposing to the atmosphere. The effect of the wind is the main loading of this structure. Under normal condition, the effect of the cross - wind has only one-fourth of the along-wind. But once the "lock-in phenomenon" happens, the cross - wind will diminish the safety of the structure. Nowadays, the analyzed simulation could not predict completely. The wind tunnel experiment could reinforce the simulation to find the better solution. This paper will design the steel towers heavily on the effect of the along- wind. The analysis of wind loading is quite complicated. Designing a tower needs a very directive system to reflect the complicated wind loading. But in Taiwan, there is no complete and unified design standard. Under this situation, either the capital cost will increase or the design will be unsafe. Thus, the main design of this paper is according to the Mainland China standards and regulations of "Design Manual for Tall Structure". Furthermore, the steel towers design is tested and verified by "Taiwanese Wind Resistant Design Code for Building", stipulated in 1995 by R&D of the ministry of domestic affairs. Through this paper, the readers will find some discrepancies of the Mainland China standards and Taiwanese standards.
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Chen, Cheng-Ying, and 陳正穎. "The Design and Analysis of Standard Tall Steel Pipe Tower With Micro-Wave Antennas." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/06359487871360713225.
Full textAbstract:
碩士中原大學
土木工程學系
87
Abstract The main purpose of this thesis is to make a standardized design and analysis of steel pipe tower. Due to the recent prosperous development of communication industry and the micro-wave antennas have often been installed at the high tower. Therefore, the safety of tall steel tower is worthy of study. 80% to 90% of distortion and stress of high micro-wave tower comes from wind force, especially along-wind force. As a result, the selection of material for high tower structure must be very important. The cross-section of circle has small size coefficient and better rigidity, which enable to use fewer tower structure materials. So as decrease tower weight, in addition the style of circular pipe is rather good-looking, and it is suitable to be used as high tower structure material. Keyword: pipe , standardize
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Hsieh, Song-Lin, and 謝松林. "The Research of the Evaluation Model on Corrosion Protection Capability for Steel Communication Tower." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/23356455128121077573.
Full textAbstract:
碩士國立成功大學
土木工程學系專班
94
To promote the quality of communication service, besides doing some emergency relief, the government is also constructing steel communication tower along the coast, mountainous area and also off-shore islands throughout the country. Recently, because of the popularity of cellular phone, a lot of new constructions and facilities have been set up. Using steel structure to build communication tower has become first choice because it has enough strength and intensity. The limitation in building steel structure is also fewer than building concrete structure, while steel is also easier to be manufactured. Taiwan is located in subtropical zone surrounded by ocean, suffers a lot of typhoon and rainstorm. The air has high humidity, while the average temperature and salinity is also high. These factors along with the pollution caused by industrial zone and vehicles have become the major threat on the corrosion problem of steel structure. Because of bad design, improper use or maintaining work, the corrosion problem in steel structure often worse than expected, which also reduced its life span. This research using Delphi method、 Analytic Hierachy Process and Fuzzy Theory,etc to establish a model to evaluate the corrosion prevention of steel structure, which then can be used to determine the condition of corrosion prevention and also as the basis of the corrosion prevention control strategy. Furthermore it can also help correlated department to maintain the tower’s safety and ensure its normal operation. The model to evaluate the corrosion prevention of steel structure is proven practicable through field investigation of specialists.
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HUNG, CHIANG CHENG, and 江正宏. "The Dssign and Analysis of Tall Steel Tower with Micro-Wave Antennas and Communication Turret." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/91711062637717921475.
Full textAbstract:
碩士中原大學
土木工程學系
87
The purpose of the current research is to discuss the design concept of tall tower structure, which includes the calculation of base pressure, tensile stress, stories shear and base moment. The numerical difference, based on Taiwan Design Code and China Design Code, are also compared and discussed. The telecommunication tower becomes taller and taller, with micro-wave antennas, in order to accommodate the vast need of the fast-growing telecommunication business, in the purpose to broaden the communicating area and increase the quality. A taller tower can also be benefit from being interferencing by surrounding buildings. In the current study, the analysis is focused on the along-wind loads, because it is the main loading for tall steel tower with micro-wave antennas. This study also analyzes the reaction of the tall tower with a turret, discusses the numerical difference between two codes, and provides the guild-line of tall tower design for industry reference. Key Word: turret, story shear, base moment
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Farhan, Muhammad. "Structural Design of the Transition Segment for an Onshore Wind Tower using different steel grades." Master's thesis, 2017. http://hdl.handle.net/10316/83166.
Full textAbstract:
Dissertação de Mestrado em Construção Metálica e Mista apresentada à Faculdade de Ciências e TecnologiaA necessidade de combater o aquecimento global tem levado a um maior interesse pelas energias renováveis e, consequentemente, a indústria eólica está passando por um desenvolvimento próspero e avanço que surge como um apelo da estratégia global de energia e questão ambiental. Um dos desafios mais críticos para a turbina eólica onshore envolve o projeto ideal da estrutura de suporte, incluindo a torre da fundação e da turbina. Com o desenvolvimento da indústria de energia eólica onshore para altitudes mais elevadas, o novo conceito estrutural de suporte pode ser comprovado ser mais vantajoso do que os tipos convencionais quando comparado em termos de custo, segurança, procedimento de montagem inovador, baixa manutenção e aspectos ambientais. Para tratar deste problema foi proposta uma nova solução de torre híbrida. A solução é direcionada para altas aplicações onshore que são mais eficazes na geração de energia em situações em que o perfil de cisalhamento do vento está claramente beneficiando turbinas mais altas. Torres híbridas em forma de rede tubular requerem uma peça de transição que serve como uma conexão entre treliça e partes tubulares. Como a peça de transição é suposto transferir todas as cargas dinâmicas e auto-peso para a rede e fundação, esses elementos estruturais apresentam características únicas e são componentes críticos para projetar e deve resistir a fortes momentos de flexão cíclica, forças de cisalhamento e cargas axiais. As peças de transição bem projetadas com otimizado estado final e capacidades de fadiga para a fabricação, contribuem para a solidez estrutural, confiabilidade e praticabilidade de novas turbinas eólicas onshore torres híbridas.Esta pesquisa centra-se principalmente na concepção e investigação da peça de transição para uma turbina eólica 5MW onshore Híbrida como referência. Usando as cargas simuladas a partir de simulações aero-elásticas e considerando os requisitos geométricos, funcionais e mecânicos, a peça de transição foi projetada para o estado limite final, considerando as não-linearidades e imperfeições incluídas no modelo de elementos finitos. Diferentes estudos de caso foram apresentados nesta tese com o objetivo de explorar diferentes possibilidades e ampliar o conceito de pesquisa. Além disso, analisá-los e compará-los com base na funcionalidade e economia nos dá maior senso de escolher uma opção viável. Nesta pesquisa, principalmente, o foco foi analisar a solução usando um reforço, peça de transição usando diferentes tipos de aço em diferentes seções, usando apenas de aço macio grau e apenas utilizando aço de alta resistência. Utilizou-se uma metodologia de simulação para prever a vida de fadiga da peça de transição, realizando a análise ELISA elástica e importando as tensões resultantes para o software de previsão da fadiga. Uma simulação de tensão multi-axial é então realizada para determinar pontos de fadiga mais realistas e tempo de vida da peça de transição. Prevê-se que uma abordagem mais probabilística deve ser utilizada para a previsão da vida de fadiga, em que a velocidade do vento está em constante mudança durante a vida útil, neste caso apenas as condições de vento extremo foram estudadas.
With the emerging concept of sustainable constructions, the need to fight global warming has led to increased interest in renewable energies and consequently, wind industry is undergoing prosperous development and advancement which comes out as a call of global energy strategy and environmental issue. One of the most critical challenges for onshore wind turbine involves the optimal design of support structure including foundation and turbine tower. With the development of onshore wind industry heading for higher altitudes, new support structural concept might be proven to be more advantageous than conventional types when comparing in terms of cost, safety, innovative erection procedure, low maintenance and environmental aspects. In order to deal with such a problem a new hybrid tower solution was proposed. The solution is targeted at tall onshore applications which are more effective in energy generation in situations where wind shear profile is clearly benefiting higher turbines.Hybrid lattice-tubular towers requires a transition piece which serves as a connection between lattice and tubular parts. As the transition piece is supposed to transfer all the dynamic and self-weight loads to the lattice and foundation, these structural elements present unique features and are critical components to design and ought to resist strong cyclic bending moments, shear forces and axial loads. Well-designed transition pieces with optimized ultimate state and fatigue capacities for manufacturing, contribute to the structural soundness, reliability and practicability of new onshore wind turbines hybrid towers.This research mainly focuses on design and investigation of the transition piece for an onshore 5MW wind turbine hybrid tower as a reference. Using the simulated loads from an aero-elastic simulations and considering the geometrical, functional and mechanical requirements the transition piece was designed for ultimate limit state with considering nonlinearities and imperfections included into the finite element model. Different case studies were presented in this thesis with the aim to exploit different possibilities and broader the concept of research. Furthermore, analyzing and comparing them on the basis of functionality and economics gives us greater sense of picking a viable option. In this research mainly the focus was to analyse the solution using a stiffener, transition piece using different grades of steel in different sections, using only mild steel grade and just utilizing high strength steel. A simulation methodology for predicting the fatigue life of transition piece was used by performing elastic FEA analysis and importing the resulting stresses into the fatigue prediction software. A multi axial strain-life simulation is then performed to determine more realistic fatigue hot spots and life time of the transition piece. It is envisaged that more probabilistic approach should be used for fatigue life prediction, in which wind speed is constantly changing over service life as in this case only extreme wind conditions were studied.
Universidade de Coimbra - European Erasmus Mundus Master Course - 520121-1-2011-1-CZ-ERA MUNDUS-EMMC Sustainable Constructions under natural hazards and catastrophic events
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Ozturk, Ferhan. "Finite element modelling of tubular bolted connection of a lattice wind tower for fatigue assessment." Master's thesis, 2016. http://hdl.handle.net/10316/38728.
Full textAbstract:
Dissertação de Mestrado em Construção Metálica e Mista apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra.One of the biggest challenges in front of the growing wind energy industry is to build higher towers for wind energy converters. In order to deal with such a problem a new hybrid tower, comprising a steel lattice lower part and a steel tubular upper part solution was proposed. The solution is targeted at tall onshore applications which are more effective in energy generation in situations where wind shear profile is clearly benefiting higher turbines, for example near forests. As part of this project, this thesis is focused on the fatigue assessment of tubular bolted connection of lattice tower. In first chapter, commercial towers for wind energy converters are briefly introduced, namely, concrete towers, welded steel shell towers, concrete/steel hybrid towers, lattice towers and hybrid lattice-tubular towers. In the second chapter, developments in fatigue analysis during the last decades and fatigue life prediction methods are given. Moreover, special emphasis is given to multiaxial fatigue life criteria which was used in fatigue life calculation of the connection used in this thesis. In the third chapter, numerical finite element modelling steps for stiffness calculation, global beam element model, and local connection model are given in detail. Additionally, finite element stress-strain results and fatigue life calculations using these results are also explained. In the last chapter, conclusions are drawn and further possible improvements of this work is suggested.
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Balagopal, R. "Experimental and Analytical Studies on Damage Detection and Failure Analysis of Transmission Towers and Tower like Structures." Thesis, 2016. http://hdl.handle.net/2005/2869.
Full textAbstract:
The transmission line (TL) tower is an important component in electrical network system. These towers consist of members (angle sections) and connections (bolted connections) plus foundation, which act together to resist externally applied loads. The latticed towers are used to support conductors in transmission network for transmission and distribution of electricity. These towers are constructed in large numbers all over the world. The connections in electric TL classical latticed towers are peculiar compared to other types of bolted connections in buildings and bridges because (i) the angle members are connected directly or through gusset plates with bolts, (ii) the eccentric application of load due to the non-coincidence of centroid axes of angle members near the connection and (iii) members are designed as beam column element to sustain tensile or compressive forces. Bearing type bolts are used in TL towers in preference to friction type bolts, because they (i) connect thin walled angle members, (ii) are easy to use for erection at all heights, (iii) can be galvanized, (iv)erosion of galvanizing can be remedied and (v) do not require skilled personnel for installation. However, these connections are subjected to reversal of stresses due to wind load. Damage in the bolted connections generally occur due to loosening of bolts due to stress reversals (Feenstra et al. (2005) [23). The damage induced after extreme wind and earthquake may lead to collapse of the whole tower. The failure of a TL tower results in power shut down, which has huge impact on national economy. Hence, the structural safety and reliable performance of these towers are extremely important. The design of TL tower is based on minimum weight philosophy. The TL towers are highly repetitive and therefore, their designs need to be commercially competitive. The TL tower design has the following deficiencies such as misappropriate design assumptions, deficit detailing, defects in material, errors in fabrication, force fitting of members during erection, variation in grade of bolts, improper gusset plate detailing, notch cutting of member, vocalization of bolt holes, etc. Hence, to check the design and detailing aspects of members along with bolted connections and to study the behavior of tower under complex loading conditions, the prototype testing of tower is made mandatory requirement in many countries throughout the world. The structural behavior of TL tower is determined from its deflection response. Thus, the full scale testing of the towers is the only way that one can counteract the un conservatism due to structural analysis. The premature failure of TL towers occurs during prototype testing due to deficiencies in joint detailing, uncertainties in framing eccentricity, force fitting of members, unequal force distribution in bolts and gusset plate connections, etc. To have better structural response of TL tower to be tested, there is need to develop reliable model for bolted connections in TL towers. The bolted connection model plays an important role in determining the deflection response and predicting the premature member buckling failure of TL towers. The issues related to prototype testing of full scale TL towers such as fabrication errors, force fitting and notch cutting of members, application of loads, joint and crossarm detailing are discussed. The need to develop bolt slip model to simulate the actual behaviour of bolted connection in TL towers is also discussed. The bolted connections in TL towers play an important role in determining its structural behavior. The angle members used in TL towers are subjected to bi-axial bending in addition to axial load. The slip will occur in the bolted connections, due to the provision 1.5 mm bolt hole clearance. In the conventional Finite Element Analysis (FEA), the bolted connections are modeled as pin joint assuming the axial load transfer. The deflection predicted from pin joint analysis in TL towers generally does not match with experimental results. The analytical and experimental deflection value varies in the range of 30 to 50%. Hence, there is need to develop model to account bolt slip for accurate deflection and dynamic characteristic prediction of TL towers. Experimental and analytical investigations have been carried out to develop and validate bolt slip model for bolted connections in TL towers. All six degrees of freedom (both translational and rotational) have been considered to simulate the exact behaviour of bolted connections in TL towers. The model is developed based on experimental results of Ungkurapinan’s bolt slip model for axial stiffness. The rotational stiffness is formulated based on the component level experiment conducted on lap joint made of steel angle with single and double bolt subjected to tensile loading. The axial and rotational stiffness for different stages of bolt tightening is also formulated based on component level experimental investigation on lap joint. The proposed model is validated by comparing with experimental results at sub-structural level on full scale king post truss subjected to tensile loading. Further the bolt slip model is validated for different bolt tightening and failure prediction of TL tower sub panel subjected to tensile loading. Finally the proposed model is also validated for full scale TL tower for deflection prediction. NE NASTRAN, a nonlinear finite element analysis (FEA) software is used for analytical simulation and the load-deflection predictions, which are compared with the corresponding experimental results. The experimental and analytical results are in good agreement with each other. The steel pole structures are replacing the conventional lattice towers, because they have smaller plan dimension and occupy less space, when compared to lattice towers. The steel pole structures are dynamically sensitive structures and the determination of their natural frequency is extremely important. For the calculation of wind load through gust factor method, the preliminary estimation of natural frequency is required. Hence, the primary step involved in dynamic analysis is the evaluation of its natural frequency. Hence, a simplified model is proposed based on model order reduction technique for the evaluation of natural frequency of TL towers and steel pole structures. For the development of base line model to detect damage in TL towers, the natural frequency has to be updated. A semi empirical approach is proposed based on the deflection by using the proposed bolt slip model. The proposed approach of updating natural frequency is validated for different cases of member damage in TL tower sub panel, such as removal of tension, compression and hip bracing members. The transmission pole structures accumulate damage during their service life. Damage in these structures will cause a change in stiffness of the system and the physical properties of these structures, such as modal frequencies and mode shapes. Hence in the present study, the damage localization study based on modified modal strain energy approach is carried out for steel pole structures and the location of damage is identified correctly. To prevent premature failure of towers during its service life testing and failure analysis of TL towers is a mandatory requirement. In the present study, forensic failure investigation of a full scale TL tower due to deficient design of a redundant member is emphasized and the remedial measures are explained in detail. The stub failure of TL tower due to reduction in cross sectional area due to unfilled bolt hole is also discussed. To investigate the effect of unfilled bolt holes on the compression capacity of leg member, detailed FEA is carried out and compared with experimental results. The reason for failure of 9 m roof top communication tower due to redundant member deficiency is also discussed. The importance of guyed tower accessories in the guy rope design of 7 m roof top guyed pole structure is also investigated. Finally, failure investigation of compression bracing member, which has failed during testing of TL tower sub panel has been investigated. The failure load is predicted by using the proposed bolt slip model in the analysis. Thus the overall research contributions emerging from this thesis are, i) development of bolt slip model accounting for rotational stiffness, ii) development of direct method of damage detection for steel pole structures based on modified modal strain energy approach, iii) development of simplified model for prediction of natural frequency of TL tower and steel pole structures, iv) development of model updating technique through natural frequency based on semi-empirical approach and v) prediction of failure load for TL tower panel using the proposed bolt slip model.
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Nuta, Elena. "Seismic Analysis of Steel Wind Turbine Towers in the Canadian Environment." Thesis, 2010. http://hdl.handle.net/1807/24269.
Full textAbstract:
The seismic response of steel monopole wind turbine towers is investigated and their risk is assessed in the Canadian seismic environment. This topic is of concern as wind turbines are increasingly being installed in seismic areas and design codes do not clearly address this aspect of design. An implicit finite element model of a 1.65MW tower was developed and validated. Incremental dynamic analysis was carried out to evaluate its behaviour under seismic excitation, to define several damage states, and to develop a framework for determining its probability of damage. This framework was implemented in two Canadian locations, where the risk was found to be low for the seismic hazard level prescribed for buildings. However, the design of wind turbine towers is subject to change, as is the design spectrum. Thus, a methodology is outlined to thoroughly investigate the probability of reaching predetermined damage states under seismic loading for future considerations.
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Yang, Ming-te, and 楊銘德. "A Planning Study Of Applying Topic Maps on Engineering Design Domain and SWOT Analysis-Steel Tower Project of Transmission Line." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/49681947075388820078.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
96
The engineers need widespread knowledge to plan the projects but also the engineering design quality effects to the results of the projects, it’s no doubts that a good engineering design promises a successful future. The new era gives us the opportunities to find out the information through internet but the data is not equal to the information neither to the knowledge. How can the managers to help the engineers to transfer the data to be information and combine the experienced judges from the decision makers to sublimate the information becomes the useful knowledge is critical for the companies and countries at present. It has become an important lesson to design the engineering design management platform to increase the work efficiency. The platform should provide a method which can help to analyze the strength, weakness, opportunity and threat. The analysis results should also produce some relative strategies for managers’ reference. Recently the information technology and internet development are speedy. To use the knowledge management to compete with the global competitors is popular. To use the IT decision system to establish a well organized and logical method will certainly improve the efficiency of decision making. The thesis used the “MindManager” software which developed by Mindjet Company to establish the engineering design system analysis and planning with topic maps. The thesis also used the tool of “oks samplers” which developed by Ontopia Company to build the topic maps and the Omnigator knowledge express tool sorts the relative documentation to assist project design relative staffs to guide and visualized the engineering knowledge and documents. The thesis will give the most complete example of the different projects’ decision advises expects to save the time and cost of the projects in order to increase the design and construction quality.
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HUANG, YUNG-CHEN, and 黃永鎮. "Analysis of Operation Strategy of Wind Power Tower Pillar- A Case Study of the Century Iron And Steel Industrial Co.,Ltd." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/7fq55f.
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碩士環球科技大學
中小企業經營策略管理研究所
106
This research focuses on how the Government promotes green energy which is being substituted for parts of fossil energy generation. Onshore wind power generation industry is full of commercial possibilities especially in green energy generation. The high price and volume of onshore wind power pillars which were limited by transit system must be domestic; therefore, CISC. has had a chance to break into onshore wind power generation pillars market. The qualitative research collecting onshore wind power generation industry materials analyzed the qualitative data and made a suggestion by interviewing the chairman of CISC.. CISC’s main successful point which was penetrating into the onshore wind power generation pillars market during 2009 to 2010, acquiring the land of Taipei Harbor and founding factories in 2014, supporting domestic policy of wind power generation by the Government, considering transportation cost of pillars, contracting MOU or collaborating, have led a position in onshore wind power generation pillars market. The research is restricted to time, subjects, and a company. Wind power generation firms strategy, industry alliance, policy association, and macroeconomics are recommendations for further research hoping could clear the full of onshore wind power generation industry.
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Li, Jia-He, and 李家和. "Design of tall Steel Communication Tower with Micro-wave Antennas on the top of Building and checked by ASD and China Specification." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/35770037780074654111.
Full textAbstract:
碩士中原大學
土木工程研究所
89
The development of telecommunication business is rapid presently, in order to broaden communicating area and increase quality, it must become taller gradually or directly sited on the top of a tall building to maintain the use of transmission. For the higher of the height, the wind effect is more important. With regard to a tall micro-telecommunication tower, the along-wind load is basic consideration, so it’s used to add on the structure for the analysis of current thesis. The thesis is aimed at the design and examination of the tower sited on a tall building, and to compare the influence of tower under different Code of wind. Also according to China Specification and Allowable Stress Design Code(ASD), we proceed the stress ratio, displacement, stability analysis of tower member and confer the difference. According to the examination of Code, we can avoid the insufficient of bearing capacity or the situation of unstable, and to maintain the safety of whole structure.
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Wu, Wei-Lin, and 吳委麟. "Design of tall Steel Communication Tower with Micro-wave Antennas on the top of Building and Check by LRFD and China Specification." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/40536206686561525606.
Full textAbstract:
碩士中原大學
土木工程研究所
89
The main purpose of this thesis is to study the behavior of tall steel micro-wave antenna tower on the top of building subjected to wind loads. This study emphasizes the along-wind effects, because it is the most significant loading of tall tower. The base moment, lateral displacements and the stress ratio of each element of the tower is checked by both China Design Code and AISC-LRFD Specification and do the comparison.
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Maximino, João Rafael Branquinho. "Hybriid Lattiice - Tubullar steell wiind towers: Conceptuall desiign of tower." Master's thesis, 2015. http://hdl.handle.net/10316/38726.
Full textAbstract:
Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra.A utilização da energia eólica não é uma nova tecnologia, mas sim uma evolução de processos e técnicas antigas. Como nos dias de hoje, a energia eólica teve um grande papel no passado, com diferentes utilizações e propósitos, embora o principal objetivo tenha sido o de facilitar os trabalhos mais pesados para o ser humano. A distribuição fácil de carvão e petróleo trouxeram uma era nova era onde a energia eólica teve que lutar para manter-se no mercado, apenas resistindo em alguns nichos financeiros, embora irrelevantes. Nos dias de hoje, com o carvão, petróleo e energia nuclear a enfrentar uma resistência cada vez maior, a energia eólica passou a ser uma solução inevitável para o problema. Assim, o principal propósito desta tese é desenvolver e otimizar uma nova solução híbrida de aço para suporte de uma turbina eólica multi-megawatt, composta por uma estrutura em treliça para a base, servindo de apoio a uma parte de aço tubular. A solução é destinada a aplicação onshore, para estruturas com alturas relevantes. No estudo levado a cabo, irá ser utilizado um novo tipo de secções transversais, com o intuito de permitir a montagem da estrutura apenas com ligações aparafusadas, tornando assim a montagem num processo mais rápido, e a estrutura mais eficiente quando sujeita a cargas de fadiga. A parte inferior introduz a possibilidade de aumentar a altura total da torre, sem ter os problemas com o transporte da estrutura ou da montagem no local, o que não seria possível utilizando apenas a parte tubular, a mais comum das utilizações. Para a otimização desta parte da estrutura, vai ser efetuado um estudo paramétrico entre várias geometrias, número de suportes e secção transversal das secções, utilizando secções circulares ocas para os elementos, com principal foco na estabilidade global e estabilidade local dos elementos.
The utilization of the wind is not a new technology, but an evolution of old processes and techniques. Like nowadays, wind power had a huge role in the past, with different utilizations and proposes, although the main goal was always to help in the Human’s heavy work. The distribution of cheap coal and oil fuels brought an era where wind energy had to fight to keep itself alive, only resisting in some irrelevant niches. Today, as the coal, oil and nuclear energy are facing an increasing resistance, the re-emerged wind power is an inevitable solution. The main objective for this thesis is to develop and optimize a new hybrid steel solution for supporting a multi-megawatt wind turbine, composed by a lower steel lattice structure, supporting a steel tubular upper part. The solution is targeted at tall onshore applications. In the study performed, a new cross section will be used, in order to be possible to assemble the lattice part only with bolted connections, making it a quicker process and more efficient when subjected to fatigue loads. The lattice part introduces the possibility to increase the total high of the tower without having the problems with the transportation of the structure for the assembly place, what would not be possible using only the steel tubular part, which is the most common use nowadays. For the optimization of this part of the structure, parametrical study of the design of the structure, with special focus on the number of supports and on the cross section of the bars, using a circular hollow section for the elements, with special attention on the global and local stability of the elements.