梁鋼筋配置最佳化實務應用之可行性評估

Feasibility of Beam Reinforcement Optimization for Practical Application

乃宥然(You-Ran Nai)

指導教授 ： 張國鎮

國立臺灣大學/工學院/土木工程學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201902072

摘要

梁鋼筋配置最佳化為將鋼筋妥善配置於鋼筋混凝土梁之方法。相較於現行鋼筋配置方法之鋼筋用量，鋼筋配置最佳化可使用較少的鋼筋用量即可達到設計需求強度。本研究依據混凝土結構設計規範，提出兩種撓曲鋼筋配置最佳化的方法，以及剪力鋼筋配置最佳化的方法。
本研究比較鋼筋配置最佳化方法(以下簡稱最佳化配筋)與現行鋼筋配置方法(以下簡稱現行配筋)之鋼筋配置的差異，探討影響最佳化配筋相較於現行配筋使用較少鋼筋用量之因素。藉由影響最佳化配筋效益的多種因素進行結構數值模型設計，量化不同因素對於最佳化配筋與現行配筋鋼筋用量的影響。依據本研究的設計案例，最佳化配筋相較於現行配筋，撓曲以及剪力鋼筋平均分別可降低8.5% 與3% 的鋼筋用量。依據兩者之配筋結果，適用於撓曲最佳化配筋的環境為(1)側向力與重力比值較小(2)梁長較長(3)影響鋼筋伸展長度較短之參數(4)梁斷面深度較小；而剪力最佳化配筋受外在環境影響較小。最後以實際建物之數值分析模型，驗證最佳化配筋預期產生之效益。而縱使目前尚未有將最佳化配筋應用於工程實務上之案例，本研究仍初步討論最佳化配筋可降低之材料成本與可能增加之施工成本的平衡。
為驗證最佳化配筋之耐震性能是否符合耐震規範。本研究比較最佳化配筋與現行配筋之耐震性能，以容量震譜法、模態側推分析方法與多模態疊加方法，進行非線性靜力側推分析。並以設計地震與最大考量地震等級之地震歷時，進行非線性動力歷時分析。最後以增量動力分析方法，透過逐步增加地震歷時強度等級，評估最佳化配筋之極限耐震性能。

關鍵字

梁鋼筋最佳化配置 ； 梁撓曲鋼筋切斷點 ； 實務應用可行性評估 ； 非線性靜力分析 ； 非線性動力分析 ； 增量動力分析

並列摘要

The optimization of beam reinforcement is a method of properly arranging the reinforcement in the reinforced concrete beam. Compared to the current reinforcement designing method (hereinafter referred to as the current method), the optimized reinforcement can use less reinforcement to achieve the design strength. According to "Design Code for Concrete Structures", this paper proposes two methods for optimizing the flexural reinforcement and the method of optimizing the shear reinforcement.
This study compares the differences between the optimal reinforcement method and the current method and discusses the factors affecting the optimal reinforcement method compared with the current method. The numerical structure design is carried out with various factors affecting the optimal reinforcement effect, and to quantify the influence of these factors on the optimal reinforcement method and the current method. And further review the results of the reinforcement of the two, to propose that the environment suitable for optimal reinforcement is (1) small ratio of lateral force to gravity (2) longer beam (3) parameters affecting development length shorter (4) smaller beam section depth. This study uses the numerical analysis model of the actual building to verify the expected benefits of optimized reinforcement. Even though there is no case of applying the optimized reinforcement to engineering practice, this study still initially discusses the balance between the material cost and the possible increase of construction cost.
To verify the seismic performance of the optimized reinforcement. The seismic performance of the optimal reinforcement method and the current method, evaluate by capacity spectrum method, modal pushover analysis, multi-modes combination method, nonlinear dynamic analysis, and incremental dynamic analysis.

並列關鍵字

beam reinforcement optimization ； flexural reinforcement cutoff point ； practical application feasibility assessment ； nonlinear static analysis ； nonlinear dynamic analysis ； incremental dynamic analysis

參考文獻

ACI. (2005). Building code requirements for structural concrete (ACI 318-05) and commentary (ACI 318R-05).

ACI. (2014). Building Code Requirements for Structural Concrete (ACI 318-14): Commentary on Building Code Requirements for Structural Concrete (ACI 318R-14): an ACI Report: American Concrete Institute. ACI.

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ASCE. (2014). Seismic Evaluation and Retrofit of Existing Buildings.

ATC. (1996). Seismic evaluation and retrofit of concrete buildings.