- 學位論文
大跨度圓頂結構系統受風行為及耐風設計之探討
THE DYNAMIC BEHAVIORS OF LARGE SPAN HEMI-SPHERICAL DOMES UNDER WIND LOADS
摘要
大跨度圓形屋蓋結構的耐風設計與評估，一般多依據風力規範或是風洞實驗數據計算而得。風洞縮尺模型試驗雖然最為準確，但也費時且所費不貲。因此在工程實務上，若是在初步規劃設計階段，能夠快速且相對準確提出耐風評估的流程，確有其重要性。本文根據風洞實驗數據，首先以非線性迴歸模型及建構圓形屋蓋結構的風壓頻譜，據此應用多點自迴歸模式(AR)，模擬產生表面風壓時間歷時，進行時域動力分析。本文建構了三種不同結構系統之圓頂結構有限元素模式，以時域動力分析評估其抗風能力。研究結果顯示，幾何非線性效應對大跨度圓頂結構的受風力行為有相當程度的影響，耐風設計評估時不可忽略。本文研究亦顯示，現行我國建築物耐風設計規範及美國ASCE 7-10風荷載規範之設計風荷載未能合理的考量大跨度圓頂結構的結構動力特性，致使根據此風力規範所得之結構反應明顯低於本文計算流程結果。
並列摘要
In engineering practice, the wind resistant design of long span dome is based on either building wind code or wind tunnel test. Wind tunnel test is the most accurate procedure among all; but the process is also expensive and time-consuming. Therefore, it is meaningful to have a less costly procedure that can produce a reasonably accurate wind loads for the wind resistant design of long span dome, at least in the preliminary planning and design stage. In this article, firstly, nonlinear regression models of wind pressure spectra were constructed based upon wind tunnel data. Then auto-regressive model (AR) was used to generate the surface wind pressure time histories to be used as in the subsequent time domain dynamic analysis. In this article, finite element model of three different structural systems were constructed for the hemi-spherical dome. Then, wind tunnel produced surface pressure time histories were used to perform time domain dynamic analysis on these dome structures. The comparative studies indicate that the geometric non-linearity plays an important factor in the hemi-spherical dome structural behavior under wind loads; ignoring it would cause noticeable underestimation. Furthermore, the equivalent static design wind loads in the existing building wind codes tend to be significantly un-conservative.