溫室結構抗風最佳化設計

Optimal Wind Resistant Design of Greenhouse Structures

葉廷傑(Ting-Jie Yeh)

指導教授 ： 劉明怡

中原大學/工學院/土木工程研究所/碩士(2019年)

https://doi.org/10.6840/cycu201900029

摘要

本研究執行受風力作用之溫室結構最佳化設計，分為兩個階段。第一階段係建立風力模式，以「建築物耐風設計規範及解說」(2015)為基礎，除了考慮室外風壓之外，亦考慮室內風壓為正值或負值兩種情況，在四類基本設計風速之條件下，分別估算溫室外牆與屋頂兩者承受之風壓，並估計其形成之風力載重；第二階段係進行結構最佳化設計，在六類溫室型態之條件下，分別計算其受風力作用產生的內力與幾何兩種反應，並以「鋼結構容許應力設計法規範及解說」(2010)為基礎，選擇各個桿件斷面尺寸為設計變數，在各個桿件的長細比、組合應力，二項指標之需求容量比均不超過1.0的限制條件均成立之前提下，設定整體結構重量極小化為目標函數，利用基因演算法搜尋各個桿件斷面尺寸的最佳參數，在確保安全性之情況下，評估並比較各種增設補強桿件型態的經濟性。結果顯示無補強桿件之抗彎矩構架具有最小重量，亦即其經濟性最佳。此外，相較於兩個設計變數，具四個設計變數之所有構架均具有較小重量，亦即其經濟性較佳。相較於無室內風壓之情況，有室內風壓之溫室的內力與變形反應均具有較大値，因此，為確保安全性，進行溫室結構設計時應考慮室內風壓。

關鍵字

溫室 ； 風力模式 ； 結構最佳化設計

並列摘要

The objective of this study is to conduct the optimal wind resistant design of greenhouses. The framework of this study consists of two stages. In the first stage, the wind load model is developed based on the Wind Resistance Design Specifications and Commentary of Buildings (2015). In addition to the external wind pressure, both the positive and negative internal wind pressures are considered. The wind pressures of outer walls and those of roofs are estimated, and the corresponding wind loads can then be calculated for four categories of basic design wind speeds. According to the results obtained in the first stage, the optimal structural design of greenhouses are conducted based on the Allowable Stress Design Specifications and Commentary of Steel Structures for Buildings (2010) in the second stage. The internal forces and displacements of greenhouses are calculated, and the corresponding cross-sectional diameters of each member can then be selected for six types of greenhouses. With the restriction of the slenderness and combined stress ratios both less than 1.0, the optimal cross-sectional diameters of each member can be determined by minimizing the overall weight of a structure. The results indicate that the moment-resisting frame without retrofit is the most economical type of greenhouse. Furthermore, the frame with four design variables is more economical than that with two design variables. Compared to the cases without internal wind pressure, the internal forces and displacements of greenhouses are significant large for the cases with internal wind pressure. Consequently, the internal wind pressure has to be considered for the design of greenhouses.

並列關鍵字

Greenhouse ； Wind Load Model ； Optimal Structural Design

參考文獻

Goldberg, D.E. (1989). “Genetic algorithms in search, optimization, and machine learning.” Addison-Wesley Publishing Company, Reading, Boston, Massachusetts, USA.

Goldberg, D.E., and Samtani, M.P. (1986). “Engineering optimization via genetic algorithm.” Proceedings of the Ninth Conference on Electronic Computation, ASCE, 471-482, New York City, New York, USA, February 23-26.

Kendirli, B. (2006). “Structural analysis of greenhouses: A case study in Turkey.” Building and environment, 41(7), 864-871.

Kociecki, M., and Adeli, H. (2014). “Two-phase genetic algorithm for topology optimization of free-form steel space-frame roof structures with complex curvatures.” Engineering Applications of Artificial Intelligence, 32, 218-227.

Li, J.P. (2015). “Truss topology optimization using an improved species-conserving genetic algorithm.” Engineering Optimization, 47(1), 107-128.