周遭建築物對屋頂風壓影響之實驗研究;Influence of Adjacent Buildings on the Roof Pressures of Downwind Buildings

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Title:	周遭建築物對屋頂風壓影響之實驗研究;Influence of Adjacent Buildings on the Roof Pressures of Downwind Buildings
Authors:	葉鑫;Yeh, Hsin
Contributors:	土木工程學系
Keywords:	風壓係數;風洞實驗;建築物間距;極值風壓;甘保機率分布;Wind tunnel experiment;Pressure coefficient;Building spacing;Peak pressure;Gumbel distribution
Date:	2019-07-30
Issue Date:	2019-09-03 12:13:52 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究使用風洞模型實驗探討低矮建築物前棟對後棟建築物表面風壓的影響，在不同風向角、不同間距下，量測建築外牆與屋頂的風壓分佈以計算其所受風力。實驗結果顯示：當風向角22.5o時，會因為屋頂角偶處渦流，使得屋頂發生最大的時間平均風壓係數 -1.46。本研究並使用獨立峰值法以及分段法取樣分析極值風壓的發生機率，分別計算其甘保機率函數以及通用型極值機率函數，比較結果顯示分段法計算得之極值風壓高於獨立峰值法的結果。此外，本研究建議一個尖峰因子g來推算極值風壓，計算結果與建築物耐風設計規範(2015)建議之極值風壓比較，發現建築物耐風規範低估屋頂的極值風壓，利用準穩態假設計算之極值風壓較安全。最後，再利用實驗量測之風壓計算對後棟建築物時間平均風壓和極值風壓的干擾係數，干擾係數會隨著間距增加而增加。當間距為6倍建築物高度且風向0o時，時間平均風壓的干擾係數會趨近於0.90；當風向於22.5o以及67.5o，干擾係數會趨近於1.0，亦即不再受前棟建築物的影響。;This study uses wind tunnel experiments to investigate the effect of upwind cubic building on the surface pressures of a downwind building. The surface pressures of the cubic building were measured under different wind directions and spacing between the buildings. The experimental results revealed that the maximum negative pressure occurred when the wind direction is 22.5o, due to the conical vortices at the building roof. The independent peaks method and segment method were used to determine the extreme values of surface pressures. The Gumbel distribution and the General Extreme Value (GEV) distribution were used to describe the probability of extreme pressures. The comparison results show that the peak pressures calculated by the segment method were larger than that by the independent peaks method. Based on the measured pressures, a gust pressure factor g was suggested to compute the peak pressures, and compared with the peak pressure coefficients recommended by the wind code of Taiwan (2015). This method can be used to predict the extreme wind pressure on the building walls. Furthermore, an interference factor is used to quantify the interference effect of upwind buildings to the surface pressures of downwind building. It was found that the surface pressure of the downwind building is no longer affected by the upwind building when the spacing is larger than 6 times of building height and the wind direction is 22.5o and 67.5o.
Appears in Collections:	[Graduate Institute of Civil Engineering] Electronic Thesis & Dissertation

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