In Hong Kong and other Asian metropolitan cites, high-rise residential buildings become very common. They are highly wind-sensitive, subjected to enormous wind loads at high wind speeds and may exhibit aeroelastic behavior at normal wind speeds. Many residential buildings often have an irregular shape with apartments arranged as wing sections extending from a central core so that all apartments on the floor can enjoy views. Between adjacent building wings are deeply recessed cavities. Most wind loading codes and guidelines assume stagnant flow inside the recessed cavities and wind loads are calculated based on the simplified enveloping building shape. This research studies how the static and dynamic wind loads on a tall building are modified by the presence of recessed cavities. The H-section tall building, with square enveloping shape, is selected to represent a building with two recessed cavities. A number of these building models with a systematic variation of breadths and depths of the recessed cavities are tested in the wind tunnel. Fluctuating wind forces and moments on the building models are measured and the dynamic building responses are investigated by the HFFB technique. The results show significant reductions in across-wind load fluctuations on the H-section buildings at wind incidence normal to building face with a cavity. Greater reductions are found on the fluctuation levels and the spectral energies at the vortex excitation frequency when the width/depth of the recessed cavities becomes larger. A resonant across-wind response modification factor (RMF) is adopted to quantify the effect on wind-induced dynamic building responses. For the across-wind response at critical wind incidence, the presence of recessed cavities can lead the value of RMF to as low as 0.67, that is reduction of building responses by 33%. To understand the mechanism of wind load modification caused by the presence of recessed cavities, wind pressure on all faces of the H-section tall buildings including the cavity faces are measured. Correlations of across-wind forces contributed by different building faces are analyzed. A clear quasi-periodic fluctuating component is found on the forces from the two building side faces and they act in phase in the across-wind direction. The across-wind force contributions from side faces of the windward or leeward recessed cavity are generally out-of-phase. As a result, the overall excitation levels of the total across-wind force on the building are reduced due to the presence of recessed cavities. To complement the wind tunnel study, computational fluid dynamics modeling using large-eddy simulation (LES) is carried out to study the unsteady wind flow around and wind loads on the H-section tall building with the widest and deepest recessed cavities. Furthermore, the two-dimensional (2D) case of smooth flow past 2D H-section cylinders is investigated. Both the LES and 2D experimental results give consistent observations and mechanisms of the effects of recessed cavities on the modification of dynamic wind loads on the tall building as the wind tunnel results. The thesis also reports studies on the effects of upstream terrain types, building heights and building shapes on the wind effects of H-section tall buildings. / published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

Wind loading considered in the design of overhead transmission lines is based on extreme values of synoptic wind, i.e. boundary layer wind originating from largescale meteorological pressure systems. Localized high intensity wind (HIW) storms such as tornadoes and downbursts are a different type of extreme wind frequently causing failures of overhead lines. This thesis covers the design aspects of overhead transmission lines when subject to localized HIW storms. A comprehensive review of the literature is included on the effects of such wind storms on lines and on mitigation measures. Furthermore, several options for the design of self-supporting transmission towers against localized HIW are discussed based on numerical simulations of several simple load cases on four examples of lattice structures.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 87-95). Also available on the Internet.

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Thesis (M.S.)--University of Wyoming, 2008. / Title from PDF title page (viewed on August 9, 2009). Includes bibliographical references (p. 96-99).

Thesis (Ph. D.)--Oregon State University, 2005. / Printout. Includes bibliographical references. Also available via the World Wide Web.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24293号 / 工博第5066号 / 新制||工||1791(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 八木 知己, 教授 KIM Chul-Woo, 教授 高橋 良和 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering. Johannesburg 2017 / The present study investigates the possibility of designing a catenary barrel vault, which can be implemented in regions where extreme tropical storms are frequently experienced. It moreover investigated the effect of non-uniform wind loads on catenary barrel vaults, and how to solve for these load conditions efficiently. The effects of high, non-uniform wind loads were assessed, and possible solutions were explored to determine a structurally efficient solution in resisting the loads applied. Different analysis and design techniques were explored in this research. These techniques included the optimization of the geometry, in resisting the applied loads most efficiently, as well as the structural design of the section in ensuring a durable and safe structure. The study revealed that the geometry of the structure cannot be optimised to resist the applied loads in a catenary fashion without external aid. By draping the vault in a post-tensioned basalt geogrid mesh, axial compression can be increased in the section and geometry optimisation can be achieved in resisting the applied loads in a catenary fashion. Three post-tensioning techniques were investigated and discussed. / MT 2018

This research is aimed at investigating and analyzing the rain-windinduced cable vibration phenomena experienced in cables of cable-stayed bridges and also the countermeasures employed by engineers to mitigate the large-amplitude vibration problem reported by various researchers around the world. In order to investigate the problem of the water rivulet creation at the top of the cable surface, a single-degree-of-freedom (SDOF) analytical model was developed and analyzed. This thesis studies the aerodynamic instability of cables in cable-stayed bridges by doing literature review of a typical in-situ test, developing a single degree-of-freedom (SDOF) analytical model, and an ANSYS finite element model. Furthermore, a linear viscous damper that acts as a countermeasure to the large amplitudes of vibration is reported and analyzed. The suppression characteristics and damper effectiveness of such countermeasure are summarized. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection