高層建築抗風可靠度分析

Reliability Analysis of High-Rise Buildings under Wind Loads

李玉潔(Yu-Jie Li)

指導教授 ： 劉明怡

中原大學/工學院/土木工程研究所/碩士(2010年)

https://doi.org/10.6840/cycu201100951

摘要

傳統結構分析使用定值法，假設分析模式中，所有參數均為單一數值，事實上，結構物在設計、施工、營運與維護等階段均存在不確定性，因此，定值法無法合理地模擬結構行為。可靠度分析以機率法為基礎，可模擬所有參數之機率分佈，因此，能適當地反映結構不確定性，較定值法更合理地描述系統特性。由於台灣位於西太平洋颱風區，颱風災害頻繁，影響高層建築結構安全性和使用者舒適性甚鉅，因此，風力為結構設計時必須考慮的重要因素。風力可視為隨機外力，具有不確定性，且高樓結構物本身之參數存在隨機性，因此，可靠度分析為探討高層建築受風力作用的有效工具。
本研究針對結構彈性中心偏移與否，提出數值算例，以執行高層建築抗風可靠度分析，分為兩個階段。第一階段係利用定值分析，在各種風攻角之條件下，計算彈性中心偏移的高層建築受風力作用之加速度反應值，亦即需求，且以高層建築使用者舒適性標準為基礎，推估結構加速度反應容許值，亦即容量；第二階段則基於第一階段所得的需求和容量，進行可靠度分析，假設結構彈性中心偏心距具有不同機率分佈形式之情況下，估算系統不滿足使用者舒適性標準的機率。結果顯示相較於對數常態分佈與型I極值分佈，利用常態分佈模擬彈性中心偏心距不確定性之結構設計具有較為保守的特性。

關鍵字

風力 ； 高層建築 ； 可靠度分析 ； 風攻角 ； 彈性中心

並列摘要

Traditionally, structural analysis is based on deterministic approaches, i.e., each parameter of analytical model is considered to be a certain value. In fact, uncertainties exist in design, construction, operation and maintenance of real structures. Consequently, traditional analysis is not able to effectively capture structural properties. On the basis of probabilistic approaches, reliability analysis is used to simulate probability distribution of each parameter, implying that uncertainties can be reasonably modeled by such method. This fact indicates that reliability analysis is a more appropriate tool than traditional analysis. In Taiwan, both structural safety and occupant comfort of high-rise buildings have become important due to frequent typhoons, implying that wind hazard is a significant factor for design purposes. Uncertainties of both wind loads and high-rise buildings have to be considered for structural design. From the above description, reliability analysis is useful for exploring the problem of high-rise buildings under wind loads.
The objective of this paper is to conduct the reliability analysis of high-rise building under wind load. Numerical examples are provided to capture the dynamic effects of elastic center eccentricity in the structure. The framework of this paper consists of two stages. The first stage includes two parts: the computation of wind-induced acceleration responses for a variety of attack angles, i.e., demand, and the determination of allowable acceleration response based on the comfort criterion of occupants in the building, i.e., capacity. According to the results obtained in the first stage, the reliability analysis is conducted in the second stage, which can predict the probability of failure for a variety of probability distributions of elastic center eccentricity. The results indicate that, compared to both lognormal and type I extreme value distributions, the normal distribution can more conservatively simulate the uncertainties of elastic center eccentricity from the design viewpoint.

並列關鍵字

Elastic center ； Reliability analysis ； Attack angle ； Wind load ； High-rise building

參考文獻

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