不同矩形斷面之高層建築設計風荷載研究

An Investigation on Design Wind Loads of Rectangular Cross-Section Tall Buildings

賴子晴(Tse-Ching Lai)

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(2013年)

https://doi.org/10.6846/TKU.2013.00953

摘要

作用於高層建築物之風荷載，主要受順風向、橫風向與扭轉向3種不同方向之風力影響。現今國內風力規範除順風向風力可依循準穩定定理與條狀定理進行合理計算，橫風向及扭轉向風力則尚須受限於使用條件之幾何形狀，依照經驗公式及圖表進行最簡化之計算，因此無法完全描述風力的複雜多樣性。
本文以國內現行規範定義之地況A、B、C作為逼近流場，並選取斷面深寬比為1/5、1/4、1/3、1/2.5、1/2、2/3、1/1、3/2、2/1、2.5/1、3/1、4/1、5/1，高寬比為3、3.5、4、4.5、5、5.5、6、6.5、7之矩柱模型，進行量測建築物表面風壓之風洞實驗，從中探討作用於建築物各方向風力特性與其空間相關性。
透過風壓實驗獲得設計風荷載所需之參數，於文章最後實行數值分析計算10棟不同幾何形狀建築物之設計風載重，其建物斷面深寬比為1/5、1/3、1/1、3/1、5/1，高寬比為3、6，流場則依台灣現行規範定義之3種地況特性進行模擬。估算風荷載之模式經由淡江大學風工程研究中心多年之研究成果，選用其分析公式撰寫程式做風力載重的運算，評估結果分別與風洞實驗歷時風力資料之結構分析結果及台灣風力規範計算結果做比較。結果顯示，本文分析程式預測結果尚可反應出風洞實驗動力歷時結構分析，因此程式計算之風載重應能有效顯示建築物的實際受力，但分析程式與國內現行風力規範之設計風載重有相當不同之差異，尤其規範在地況A幾乎過於保守，而地況B、C甚至出現過於低估的情況，因此本文計算程式應可較風力規範準確。

關鍵字

高層建築 ； 順風向 ； 橫風向 ； 扭轉向 ； 設計風載重 ； 風洞實驗

並列摘要

The wind load acting on high-rise building, mainly used for alongwind, acrosswind, torsional the 3 different types of wind effects. Among the three design wind loads, only the alongwind load can be estimated analytically based on the quasi-steady theorem and strip theory. Due to the complexity of the vortex shedding phenomenon, estimation of acrosswind and torsional wind loads are depended heavily on the empirical formulae. In the current Taiwan building wind code, the acrosswind and torsional design wind loads are limited to certain building geometric shapes.
This thesis conducted systematic wind tunnel test on tall buildings with various geometric shapes in turbulent boundry layers generated over urban, suburban and open terrains. The side ratio of building models covers L/B= 1/5、1/4、1/3、1/2.5、1/2、2/3、1/1、3/2、2/1、2.5/1、3/1、4/1、5/1 ; and the aspect ratio covers h/√BL= 3、3.5、4、4.5、5、5.5、6、6.5、7. For each bulding model, hundreds of surface pressures were measured simultaneously by high speed pressure scanner, and then the local and global wind force coefficients and various correlations were carefully investigated to gain the insights of building loads.
Through these wind tunnel experiments and the data analysis, the necessary data for developing the design wind loads were acquired. The design wind load estimation models adopted in this thesis were developed by Tamkang University Wind Engineering Research Center over past years. These calculated design wind loas were then compared with wind tunnel measurements and Taiwan building wind code. The results show that these formulae are in good agreement with the wind tunnel measurements. In other words, these desing wind load formulae are adequate to be applied to building wind resistant design. On the other hand, the estimated design wind loads show significant differences in many cases with the current Taiwan building wind code. It can be concluded that the formulae used in this thesis can produce more accurate building design wind loads than the Taiwan building wind code.

並列關鍵字

Tall Building ； Alongwind ； Acrosswind ； Torsion ； Design Wind Load ； Wind Tunnel Test

參考文獻

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