本文提出順風向設計風力修正模式。本文模式根據風洞實驗數據假設迎風面之平均風力及擾動風力在高度上分佈遵循條狀定理(Strip theory)與準穩定理論(Quasi-steady theorem);背風面風力則為均勻分布。擾動風力之背景部份引入折減因子以適度考慮空間相關性的影響;共振部份之設計風力則依慣性力進行高度上的分配。依據上述風力架構,提出新的順風向設計風力模式。首先將新風力模式與常用的DGLF (Displacement-based gust loading factor)與MGLF (Moment-based gust loading factor)二種模式進行比較。計算結果顯示,本文模式之平均風載重與擾動風載重之背景部份高於DGLF與MGLF;擾動風載重之共振部分,與MGLF相當吻合。與現行規範比較結果顯示:在高樓層處,根據規範計算所得之設計風力較本文模式偏低,在較低樓層區域則則有偏高的趨勢。此外,本文選取一棟124公尺高之矩形斷面高層建築,製作風壓模型,分別在地況A (α=0.25)與地況C (α=0.15)的邊界層流場中進行風洞試驗。風洞試驗結果與本文模式比較結果顯示,本文推導之風載重計算模式,在有關風力於高度上分佈之修正,能有效反映建築物受風作用下之真實情形。 A modified model for alongwind design wind load is proposed. In this model, the mean and dynamic wind forces on the windward face follow the strip theory strictly; the wind forces on the leeward face assumed to be uniformly distributed. A correlation reduction factor is introduced to amend the spatial correlation effect on the background part wind load. The resonant part of dynamic design wind load is distributed based on the inertia force. Numerical study is then performed on a 200m prototype building. The equivalent static wind load based on the present model is compared with DGLF, MGLF and current wind code. The proposed wind load model was then compared with the wind tunnel test results of a prototype 124 m building. The comparative studies indicate that the proposed model produces a better accurate design wind load estimate than the other procedures.
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中華民國第八屆結構工程研討會論文集=Proceedings of the 8th National Conference on Structural Engineering,10頁