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An experimental wind tunnel study on the dynamic response of a 300 m tall guyed telecommunication mast under various wind loads was undertaken at the Boundary Layer Wind Tunnel Laboratory (BLWTL) in the University of Western Ontario, London, Canada. Although the dynamic response of guyed masts subjected to turbulent wind loads has been routinely analyzed using a number of numerical models, typically in the frequency domain, limited experimental verification of the dynamic analysis results has been performed. Full-scale measurements, where available, have proven to be difficult to correlate with analytical models due to the tremendous uncertainty inherent in field measurements. As a result, the need for systematic validation of existing analytical models remains.<p>In this investigation, a representative 300 m tall guyed telecommunication mast has been designed and modeled to an appropriate scale. Based on Canadian Standard CSA S37-01, and an empirical study on 41 existing guyed masts, the 300 m tall guyed mast was designed using wind load conforming to representative Canadian climate data obtained from National Building Code of Canada (NBCC 1995). Appropriate properties for the dynamically scaled full aeroelastic model were derived from the 300 m tall prototype guyed mast, which was intended to represent a realistic guyed mast for broadcasting applications in Canada.<p>The wind tunnel test of the guyed mast model was carried out in both open country and over water exposures, simulating medium and low turbulence flow conditions, respectively. Dynamic response characteristics measured during the wind tunnel tests have been analysed and summarized, including dynamic displacements, bending moments, response spectra and peak factors, as well as natural frequencies, mode shapes and structural damping. Comparisons have been made with predictions obtained from an existing frequency domain analysis model. <p>The wind tunnel test results show that good agreement was generally achieved between the frequency domain analytical model and the wind tunnel model with respect to both the magnitude and distribution of the monitored responses. It was found that measured dynamic bending moments were distributed in a fairly uniform manner over the mast height, and that mean (static) bending moments exhibit large variations, along with near-zero response zones at points of contraflexure. It was also found that nonlinear damping effects, associated with vibrations of the highly slackened leeward guys on the upper levels of the mast, may be beneficial in reducing dynamic mast displacements. <p>The spectrum studies indicated that lowest modes were dominated by large guy movements at top guy level and small mast movements, the middle modes were characterized by coupled effects between the guyed cables and mast, meanwhile the highest modes involved significant mast movements with little guy vibration. It is evident that the top of the mast displacement are dominated by the first and second modes.

An experimental wind tunnel study on the dynamic response of a 300 m tall guyed telecommunication mast under various wind loads was undertaken at the Boundary Layer Wind Tunnel Laboratory (BLWTL) in the University of Western Ontario, London, Canada. Although the dynamic response of guyed masts subjected to turbulent wind loads has been routinely analyzed using a number of numerical models, typically in the frequency domain, limited experimental verification of the dynamic analysis results has been performed. Full-scale measurements, where available, have proven to be difficult to correlate with analytical models due to the tremendous uncertainty inherent in field measurements. As a result, the need for systematic validation of existing analytical models remains.<p>In this investigation, a representative 300 m tall guyed telecommunication mast has been designed and modeled to an appropriate scale. Based on Canadian Standard CSA S37-01, and an empirical study on 41 existing guyed masts, the 300 m tall guyed mast was designed using wind load conforming to representative Canadian climate data obtained from National Building Code of Canada (NBCC 1995). Appropriate properties for the dynamically scaled full aeroelastic model were derived from the 300 m tall prototype guyed mast, which was intended to represent a realistic guyed mast for broadcasting applications in Canada.<p>The wind tunnel test of the guyed mast model was carried out in both open country and over water exposures, simulating medium and low turbulence flow conditions, respectively. Dynamic response characteristics measured during the wind tunnel tests have been analysed and summarized, including dynamic displacements, bending moments, response spectra and peak factors, as well as natural frequencies, mode shapes and structural damping. Comparisons have been made with predictions obtained from an existing frequency domain analysis model. <p>The wind tunnel test results show that good agreement was generally achieved between the frequency domain analytical model and the wind tunnel model with respect to both the magnitude and distribution of the monitored responses. It was found that measured dynamic bending moments were distributed in a fairly uniform manner over the mast height, and that mean (static) bending moments exhibit large variations, along with near-zero response zones at points of contraflexure. It was also found that nonlinear damping effects, associated with vibrations of the highly slackened leeward guys on the upper levels of the mast, may be beneficial in reducing dynamic mast displacements. <p>The spectrum studies indicated that lowest modes were dominated by large guy movements at top guy level and small mast movements, the middle modes were characterized by coupled effects between the guyed cables and mast, meanwhile the highest modes involved significant mast movements with little guy vibration. It is evident that the top of the mast displacement are dominated by the first and second modes.

Estruturas alteadas são fortemente afetadas pelas ações naturais, que são por sinal, as ações de maior complexidade na engenharia estrutural em função do grande número de variáveis envolvidas. O vento é uma destas ações e também uma das mais importantes em condições gerais. Em projeto, a ação do vento é normalmente considerada através das indicações normativas de cada país, que são, em função de sua complexidade, descritas na forma de métodos estático equivalentes, suficientes para maioria dos casos. Este critério não difere ao se tratar de linhas de transmissão, no entanto, grande parte das normas do mundo basearam-se no comportamento das torres autoportantes, mas que vêm sendo igualmente utilizadas em projetos de torres estaiadas. Por este motivo, se propõe a análise estatística de esforços de uma torre estaiada, modelada em conjunto com os demais componentes de uma linha de transmissão, de modo a compará-los aos resultados obtidos pelo método estático equivalente da IEC 60826 (IEC 2003). A hipótese de carregamento estudada é a ação transversal do vento na linha. Na simulação numérica, diversos campos aleatórios de velocidades são gerados, sendo as ações também calculadas pela formulação da norma IEC 60826. Os campos foram gerados por dois diferentes métodos, o método de Deodatis (1996) e método de Riera e Ambrosini (1992), ambos baseados no método de superposição de ondas. O espectro de velocidades utilizado neste trabalho é o espectro de Davenport. Apesar de saber da importância de outras fontes de não linearidades, foram consideradas neste trabalho: a não linearidade geométrica dos componentes, computada automaticamente com o uso do método de integração explícito por diferenças finitas centrais, e a não linearidade física dos cabos suspensos. Diferentes parâmetros de amortecimento foram testados para os componentes estruturais. Nos resultados é possível observar que a IEC 60826 mostrou-se suficiente na estimativa de esforços da maioria dos elementos analisados, no entanto, nas barras pertencentes ao mastro da torre verificaram-se valores normativos inferiores aos calculados pelo método numérico. Nestas barras, a diferença chegou a aproximadamente 22% pelo método de Deodatis (1996) e a 12% pelo método de Riera e Ambrosini (1992), ambos na configuração de menor amortecimento testada e para o intervalo de confiança de 98%. / High structures are strongly affected by natural loads, which are the most complexity loads in the structural engineering due the large number of variables involved. The wind is one of these actions and one of the most important in general conditions. In design, the action of wind is normally accounted through the country‟s standards indications which, due to its complexity, are usually descripted by equivalent static methods, enough in the most cases. This criterion does not differ for transmission lines, however, the most of standards in the world were based on the self-support towers behavior, but they are also being used for guyed towers design. Therefore, in this study is proposed a statistic analysis of internal forces in the guyed tower elements, modeled together with the other transmission lines components, in order to compare them with the results obtained by equivalent static method of IEC 60826 (IEC 2003). The load hypothesis is the across wind action. In the numerical simulation, several random velocity fields were generated, the actions being calculated by the formulation of IEC 60826 standard. The fields were generated by two different methods, the method of Deodatis (1996) and the method of Riera and Ambrosini (1992), both of them are based in the wave superimposition method. The power wind spectrum (PSD) used in this work is the Davenport‟s spectrum. Although knowing the importance of other nonlinearities, were considered in this work: the geometric non-linearity of all elements, which are automatically computed by explicitly integration method by central finite differences used, and the physic non-linearity of suspended cables. Different damping rates were considered for the structural components. In the results, it is possible to observe that the IEC 60826 was enough in the estimation of internal forces on the majority of elements analyzed, however, on the tower mast bars were verified normative values smaller than those obtained by numerical method. In these bars, the difference among analyses reached 22% by Deodatis (1996) method and 12% by Riera e Ambrosini (1992) method, both of them considering the lower tested damping configuration and the 98% confidence interval.

[pt] Torres estaiadas são, em geral, estruturas bastante leves e esbeltas e que apresentam comportamento eminentemente não - linear. Assim, a análise de sua estabilidade sob cargas estáticas e dinâmicas é essencial para se ter um projeto econômico e seguro. Neste trabalho estuda-se a estabilidade estática e dinâmica de um modelo plano de torre estaiada. Especial atenção é dada à modelagem dos estais, que são modelados como elementos de mola (linear ou não -linear) ou como cabos inextensíveis. Faz-se, com base no princípio da energia potencial mínima, um estudo da carga crítica e do caminho pós-crítico. Um estudo paramétrico minucioso permite analisar a influência dos diversos parâmetros físicos e geométricos na estabilidade da torre e chegar às melhores configurações para os estais. Na análise dinâmica atenção especial é dada ao estudo paramétrico da freqüência natural. Com base nos resultados da análise estática, analisa-se também o comportamento global da torre em vibração livre e forçada. Em virtude das não linearidades, verifica-se que a torre pode apresentar diversos comportamentos típicos de sistemas não -lineares tais como saltos, bifurcações de período e caos. / [en] Guyed towers are in general very light and slender structures and their behavior under static and dynamic loads is eminently nonlinear. Thus the analysis of its stability under static and dynamic loads is an essential step in obtaining an economic and safe project. In this work the static and dynamic stability analysis of a plain model of a guyed tower is studied. Special attention is given to the modeling of the stays; here they are modeled as spring elements (linear or nonlinear) or as inextensible cables. A study of the critical load and the postcritical nonlinear equilibrium paths is conducted based on the principle of the minimum potential energy A detailed parametric analysis is performed to identify the influence of the physical and geometric parameters of the system on the stability of the tower. This allows one to choose the best configurations for the stays. In the dynamic analysis special attention is given to the parametric study of the system natural frequencies. Based on the results of the static analysis, the global behavior of the tower under free and forced vibration is also analyzed. Due to the inherent nonlinearities, the tower may present dynamic responses typical of nonlinear systems such as jumps, period bifurcations and chaos.

Guyed masts are special type of structures that are widely used in the telecommunication industry. In the past, there was no guideline for seismic design of these types of structures in the corresponding design codes. On the other hand, in the latest &ldquo / G&rdquo / revision of the ANSI/TIA-EIA code there is a comprehensive design criterion for the seismic design of the guyed masts. However, during the design process of these structures the most common approach is to ignore the effect of seismic loading and use only the internal forces developed from the wind load and ice load analysis. In this study firstly the efficiency and accuracy of the commercial SAP2000 and PLS-TOWER software were investigated, then finite element models of three guyed masts that had been designed in Turkey with the heights 30m, 60m and 100m in the SAP2000 and PLS-TOWER software were analyzed under the effect of earthquake, wind and ice loadings. The most common design code recognized all over the world used for the design of the guyed masts is ANSI/TIA-EIA 222-G &ldquo / Structural Standards for Steel Antenna Towers and Supporting Structures&rdquo / . Thus, the corresponding sections of this code were followed during the study. The main objective of this research is to check the correctness of commercial SAP2000 and PLS-TOWER software and to investigate the effect of seismic actions on the guyed masts and also to gain a better understanding of the behavior of guyed masts under the effects of the wind, ice and earthquake loadings.

Disertacijoje sprendžiama telekomunikacinių stiebų efektyvumo problema. Tyrimo objektas – statiškai apkrauti naujos konstrukcijos stiebai su kombinuotomis atotampomis. Darbe išanalizuota šiuolaikinių stiebų konstrukcinės formos ir skaičiavimo metodai. Nagrinėjama sukurta stiebo su kombinuotomis atotampomis konstrukcija, kurioje vietoj įprastųjų siūloma taikyti kombinuotas atotampas. Disertacijoje šiems stiebams skaičiuoti pateikta inžinerinė skaičiavimo metodika. Pateikti naujo stiebo, veikiamo statinių apkrovų, elgsenos analizės skaitinių ir eksperimentinių laboratorinių tyrimų rezultatai. Stiebo su kombinuotomis atotampomis kamieno lenkiamiesiems momentams reguliuoti darbe siūloma taikyti parengtą stiebų komponavimo metodiką. Šių stiebų efektyvumui nustatyti pateikti gretinamieji tyrimai su įprastos sandaros stiebais. Disertaciją sudaro bendroji darbo charakteristika, 5 skyriai, pagrindiniai darbo rezultatai ir išvados, literatūros sąrašas. / Тhe dissertation deals with the problem of telecommunication masts efficiency. The subject of research – masts of a new structure with combined guys under static loads. The study deals with constructive forms and analysis methods of up-to-date masts. It analyses into a created structure of the mast, wherein it is suggested to apply combine guys instead of the ordinary ones. Engineering guyed masts with combined guys static analysis method is given this research. The numerical and experimental laboratory assay of a new mast under static loads behaviour is given. It is proposed in the study to apply a worked out composing method of masts with combined guys to control the bending moments of shaft. Compared research results are given to measure efficiency of these masts against masts of an ordinary structure. The dissertation includes a general characteristic of study, five chapters, main results and conclusions, list of references.

Тhe dissertation deals with the problem of telecommunication masts efficiency. The subject of research – masts of a new structure with combined guys under static loads. The study deals with constructive forms and analysis methods of up-to-date masts. It analyses into a created structure of the mast, wherein it is suggested to apply combine guys instead of the ordinary ones. Engineering guyed masts with combined guys static analysis method is given this research. The numerical and experimental laboratory assay of a new mast under static loads behaviour is given. It is proposed in the study to apply a worked out composing method of masts with combined guys to control the bending moments of shaft. Compared research results are given to measure efficiency of these masts against masts of an ordinary structure. The dissertation includes a general characteristic of study, five chapters, main results and conclusions, list of references. / Disertacijoje sprendžiama telekomunikacinių stiebų efektyvumo problema. Tyrimo objektas – statiškai apkrauti naujos konstrukcijos stiebai su kombinuotomis atotampomis. Darbe išanalizuota šiuolaikinių stiebų konstrukcinės formos ir skaičiavimo metodai. Nagrinėjama sukurta stiebo su kombinuotomis atotampomis konstrukcija, kurioje vietoj įprastųjų siūloma taikyti kombinuotas atotampas. Disertacijoje šiems stiebams skaičiuoti pateikta inžinerinė skaičiavimo metodika. Pateikti naujo stiebo, veikiamo statinių apkrovų, elgsenos analizės skaitinių ir eksperimentinių laboratorinių tyrimų rezultatai. Stiebo su kombinuotomis atotampomis kamieno lenkiamiesiems momentams reguliuoti darbe siūloma taikyti parengtą stiebų komponavimo metodiką. Šių stiebų efektyvumui nustatyti pateikti gretinamieji tyrimai su įprastos sandaros stiebais. Disertaciją sudaro bendroji darbo charakteristika, 5 skyriai, pagrindiniai darbo rezultatai ir išvados, literatūros sąrašas.

Estruturas alteadas são fortemente afetadas pelas ações naturais, que são por sinal, as ações de maior complexidade na engenharia estrutural em função do grande número de variáveis envolvidas. O vento é uma destas ações e também uma das mais importantes em condições gerais. Em projeto, a ação do vento é normalmente considerada através das indicações normativas de cada país, que são, em função de sua complexidade, descritas na forma de métodos estático equivalentes, suficientes para maioria dos casos. Este critério não difere ao se tratar de linhas de transmissão, no entanto, grande parte das normas do mundo basearam-se no comportamento das torres autoportantes, mas que vêm sendo igualmente utilizadas em projetos de torres estaiadas. Por este motivo, se propõe a análise estatística de esforços de uma torre estaiada, modelada em conjunto com os demais componentes de uma linha de transmissão, de modo a compará-los aos resultados obtidos pelo método estático equivalente da IEC 60826 (IEC 2003). A hipótese de carregamento estudada é a ação transversal do vento na linha. Na simulação numérica, diversos campos aleatórios de velocidades são gerados, sendo as ações também calculadas pela formulação da norma IEC 60826. Os campos foram gerados por dois diferentes métodos, o método de Deodatis (1996) e método de Riera e Ambrosini (1992), ambos baseados no método de superposição de ondas. O espectro de velocidades utilizado neste trabalho é o espectro de Davenport. Apesar de saber da importância de outras fontes de não linearidades, foram consideradas neste trabalho: a não linearidade geométrica dos componentes, computada automaticamente com o uso do método de integração explícito por diferenças finitas centrais, e a não linearidade física dos cabos suspensos. Diferentes parâmetros de amortecimento foram testados para os componentes estruturais. Nos resultados é possível observar que a IEC 60826 mostrou-se suficiente na estimativa de esforços da maioria dos elementos analisados, no entanto, nas barras pertencentes ao mastro da torre verificaram-se valores normativos inferiores aos calculados pelo método numérico. Nestas barras, a diferença chegou a aproximadamente 22% pelo método de Deodatis (1996) e a 12% pelo método de Riera e Ambrosini (1992), ambos na configuração de menor amortecimento testada e para o intervalo de confiança de 98%. / High structures are strongly affected by natural loads, which are the most complexity loads in the structural engineering due the large number of variables involved. The wind is one of these actions and one of the most important in general conditions. In design, the action of wind is normally accounted through the country‟s standards indications which, due to its complexity, are usually descripted by equivalent static methods, enough in the most cases. This criterion does not differ for transmission lines, however, the most of standards in the world were based on the self-support towers behavior, but they are also being used for guyed towers design. Therefore, in this study is proposed a statistic analysis of internal forces in the guyed tower elements, modeled together with the other transmission lines components, in order to compare them with the results obtained by equivalent static method of IEC 60826 (IEC 2003). The load hypothesis is the across wind action. In the numerical simulation, several random velocity fields were generated, the actions being calculated by the formulation of IEC 60826 standard. The fields were generated by two different methods, the method of Deodatis (1996) and the method of Riera and Ambrosini (1992), both of them are based in the wave superimposition method. The power wind spectrum (PSD) used in this work is the Davenport‟s spectrum. Although knowing the importance of other nonlinearities, were considered in this work: the geometric non-linearity of all elements, which are automatically computed by explicitly integration method by central finite differences used, and the physic non-linearity of suspended cables. Different damping rates were considered for the structural components. In the results, it is possible to observe that the IEC 60826 was enough in the estimation of internal forces on the majority of elements analyzed, however, on the tower mast bars were verified normative values smaller than those obtained by numerical method. In these bars, the difference among analyses reached 22% by Deodatis (1996) method and 12% by Riera e Ambrosini (1992) method, both of them considering the lower tested damping configuration and the 98% confidence interval.