干擾效應對高層建築設計風力的影響（Ⅱ）

The Interference Effects on the design wind loads of tall buildings（Ⅱ）

王嘉國(Chia-Kuo Wang)

指導教授 ： 鄭啟明

淡江大學/工學院/土木工程學系碩士班/碩士(2006年)

https://doi.org/10.6846/TKU.2006.00159

摘要

現代社會的都會區由於可利用的土地與空間有限且日漸減少的情況下，都市往上發展，興建高層建築成為不可避免的趨勢。高層建築與一般建築不同，除了地震力之外，風力也是重要的水平向設計載重。在高樓林立之現今大都市中，除了單棟建築的風力之外，相鄰建築物間之風力交互作用也成為一重要的問題。
本文主要是以風洞試驗探討干擾效應對高層建築設計風載重之影響，並嘗試建立修正模式。風洞試驗時將干擾模型置於主要量測建築物的周圍，改變干擾模型之位置與形狀，然後比較不同干擾條件時主要量測建築物風力之變化，並以實驗數據做為修正依據，建立一修正式。風洞實驗可分為兩種類別：(1)改變干擾建物高寬比系列；(2)改變主要量測建物斷面形狀系列。風洞實驗使用高頻力平衡儀(HHFB)量測單一建築模型以及在各種干擾效應下的風力。本文根據實驗數據，計算建築物在順風向與橫風向的平均風力與擾動風力干擾係數。並配合原型高層建築結構特性，計算出結構物之設計風載重。
由本文實驗結果得知，干擾建物高度與寬度不同時，對於下游主要建物的風力會產生不同的影響。在干擾效應下，X/B=3，Y/B=0的位置時，可觀察到，改變高度對於平均風力的影響較改變寬度的影響來的小。在干擾效應下，在(X/B=3~13,Y/B=0~4)上均有放大的效果，大部份之擾動風力係數均會大於單一建築，但在主建物附近則有減小的效果。將干擾係數帶入設計風載重公式中，即可得到干擾效應下之設計風載重。

關鍵字

高層建築 ； 風洞實驗 ； 干擾效應 ； 干擾指標

並列摘要

Tall building plays an important role in the city development due to the limited land. In addition to the earthquake force, wind force becomes an important lateral design load for tall buildings. The increasing number of tall buildings in a large city makes the interference effects between the adjacent buildings becomes an important wind engineering problem. This paper investigates the interference effect on the design wind load of tall buildings. The wind tunnel experiments were conducted for different model geometry shapes and various model spacing in a grid system. The wind tunnel experiments can be categorized into two groups: (1) interference effects of inferring buildings with identical volumes but different cross-sectional shapes, (2) interference effects of inferring buildings have the same height but different building width. Design wind load were calculated for comparison. High frequency force balance was used to measure both the mean and dynamic wind loads. The interference factors for mean and dynamic wind loads on both along-wind and across-wind directions were evaluated.
The experimental results indicate that the variation of the adjacent building width would cast more influences on the average wind-force than the building height especially when the interfering building locates at X/B =3, Y/B =0. Variation of the width and height of the upstream interfering building would cause significant change in the wind loads of the target building. When the interfering building locates in the region of X/B = 3~13, Y/B =0~4, the dynamic wind loads of the target building would be enhanced except when the interfering building locates very close to the target building. Incorporating the interference factors obtained from this research into the design wind loads for an isolated building, a more realistic and accurate design wind loads can be obtained.

並列關鍵字

high-rise building ； wind tunnel ； interference effect ； interference Index

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