臺灣博碩士論文加值系統

挫屈束制支撐(buckling-restrained brace, BRB)為安裝在建築內的鋼斜撐構件，受拉時可降伏消能，受壓時藉鋼管填充混凝土來提供斜撐圍束，使其亦可達降伏不發生挫屈，可有效提升建築結構的強度、勁度、韌性及消散地震能量的能力。然而，當BRB或端部接合發生挫屈破壞造成面外不穩定時，其軸向勁度與強度將大幅縮減，喪失消散能量之功能。因此近年來國際學者投入BRB面外穩定性研究，其中日本Takeuchi教授根據BRB挫屈時的塑性行為，推導出一系列挫屈預測模型。然而其所提栓接式BRB挫屈行為並不適用於國內常用之槽接式挫屈束制支撐 (WES-BRB)，因此2017年陳力維延伸Takeuchi所提出之理論，考量WES-BRB其圍束單元較長之幾何特性，提出考量圍束單元撓曲效應及接合板旋轉效應之穩定性評估模型。但此理論模型仍需複雜計算程序，且須利用有限元素板殼模型分析接合板旋轉勁度及塑性彎矩容量，於實際工程應用較不方便。因此本文欲發展簡化理論模型，考慮軸力與撓曲互制之二次效應，採虛擬側向力及塑性分析法探討BRB及接合之面外穩定性。本研究以陳力維測試之四組實尺寸BRB試體進行實例分析，預測分析模型可反應接合板加勁及端部面外位移( OOP end-drift )對BRB穩定性之影響，其誤差皆小於5%。本研究另製造兩組長約7.3米，降伏強度為100噸之實尺寸BRB試體，於國家地震工程研究中心的多軸向試驗機進行反覆載重試驗，透過逐步增加端部面外位移量的方式，來探討端部面外位移量對BRB穩定性的影響並探求其臨界挫屈強度。本研究所提分析模型之預測結果可確實反應端部面外位移效應，對於挫屈強度的預測誤差小於2%，再次驗證所提模型之準確性及可靠性。因此本文使用本簡化穩定性評估模型，對業界常用的BRB噸數、構架尺寸與配置型式，利用雲端運算輔助設計軟體所規劃出的581組BRB設計案例進行挫屈強度預測與分析，分析顯示現行採容量設計法及極限狀態檢核所設計之BRB與接合例屬保守且安全。另透過多案例分析顯示，當BRB端部面外側位移角由1%增至2%時，挫屈強度減損幅度約介於12%至15%，對穩定性影響非常顯著；分析顯示若接合板邊緣有或無加勁，其挫屈強度減損幅度約介於5%至20%之間，因此於工程應用上，接合板加勁為必要之設計；而多設計案分析亦顯示外鋼管需求容量比DCR若控制在0.9之內，將使其面外穩定性更有保障。

Buckling-restrained brace (BRBs) are widely adopted for new construction and seismic retrofit of buildings. Properly fabricated BRBs can develop fully yielding strength under both tension and compression without flexural buckling. Therefore, BRBs can enhance the strength, stiffness, ductility and the energy dissipation capability of structures. However, when the out-of-plane (OOP) instability of the BRB and the end gusset connections occur, the axial strength, stiffness, and the energy dissipation capacity of the BRB will be significantly reduced. Therefore, a number of researchers have investigated the OOP stability of BRBs in recent years. Takeuchi et al. proposed a set of advanced procedures to assess the BRB OOP stability. However, their buckling models are not entirely suitable for the welded end-slot buckling restrained brace (WES-BRB), commonly used in Taiwan. Therefore, based on the unique characteristic of the WES-BRBs, Chen et al. incorporated Takeuchi’s procedures and proposed a buckling model considering flexural restrainer and gusset rotations in 2017. However, these procedures are not straight forward, requiring the finite element model analysis in order to compute the gussets’ rotational stiffness and strength. Thus, this study develops a simplified analytical model using notional load and plastic analysis to assess the OOP stability of BRBs. In order to verify the effectiveness of the proposed procedures, four full-scale BRB specimens tested by Chen et al. are used as example applications. The proposed model satisfactorily predicts specimens’ buckling strength with errors less than 5%. The effects of the OOP end drift and gusset edge stiffeners on the BRB stability are reasonably captured. In order to further verify the effectiveness of the proposed procedures, two full-scale BRB specimens each of 7.3m long with a 988-kN nominal yield strength were constructed and tested in NCREE. The experiments were conducted by applying cyclically increasing BRB axial strains while gradually increasing the OOP end drift until buckling was observed. The proposed model effectively predicts specimens’ buckling strength with errors less than 2%. Finally, parametric analysis were conducted on 581 BRB and connection cases, designed by the Brace-on-Demand (BOD) cloud service, varying from different yield strength values, frame span-to-height ratios and core plate dimensions, using the proposed procedures. Analytical results show the typical BRB and end connections designed by using the BOD service are generally conservative and safe. Results also indicate the overall stability is vulnerable to OOP end drift. The buckling strength can be reduced by 12% to 15% when the OOP end drift is increased from 1% to 2%. In addition, the buckling strength will be reduced from 5% to 20% without the presence of the gusset edge stiffeners. Thus, it can be concluded that adding the edge stiffener to the gusset is a good practice in the BRB applications. Analysis results show that when the DCR of steel casing is less than 0.9, the overall stability of BRBs can be effectively conserved.

致謝 i
摘要 ii
Abstract iii
目錄 iv
表目錄 vii
圖目錄 viii
照片目錄 xi
第一章 緒論 1
1.1 概述 1
1.2 研究目的 2
1.3 論文架構 3
第二章 背景與文獻回顧 4
2.1 挫屈束制支撐(BRB) 4
2.1.1 概述 4
2.1.2 組成 4
2.1.3 力學行為 5
2.2 相關文獻回顧 8
2.2.1 Chuang et al. (2015) 8
2.2.2 Takeuchi et al. (2014, 2016) 9
2.2.3 陳力維 (2017) 10
第三章 WES-BRB整體面外穩定性理論模型 11
3.1 WES-BRB穩定性條件假設 11
3.2 WES-BRB塑性分析與破壞機制的幾何形狀假設 12
3.3 破壞機制下的幾何形狀參數 13
3.4 虛擬側向力的應用 14
3.5 考量二次效應的彎矩放大因子及整體彈性挫屈強度 14
3.6 圍束段中間處及接合板處塑性彎矩容量 18
3.7 能量平衡方程式 19
3.8 WES-BRB反覆載重試驗實例應用 20
3.8.1 概述 20
3.8.2 實例介紹 20
3.8.3 G16、G16ES(II)試體的破壞機制及挫屈強度 21
3.8.4 預測破壞機制及挫屈強度之設計方法 22
3.8.5 預測破壞機制及挫屈強度之應用 23
第四章 試驗計畫與配置 24
4.1 概述 24
4.2 試驗目的 25
4.3 試體規劃 25
4.3.1 試體設計 25
4.3.2 試體製作 26
4.4 試驗配置 27
4.5 量測計畫 27
4.6 加載歷程 29
4.6.1 面外層間位移角歷程 29
第五章 試驗結果與討論 31
5.1 材料拉伸試驗 31
5.1.1 核心及接合板材料 31
5.1.2 圍束鋼管材料 31
5.2 內灌水泥沙漿彈性模數 31
5.3 摩擦力計算 32
5.4 2G16試驗結果 33
5.4.1 標準歷程(0% OOP-IDR) 33
5.4.2 0.5% OOP-IDR 33
5.4.3 1.0% OOP-IDR 34
5.5 2G16ES試驗結果 34
5.5.1 標準歷程(1.0% OOP-IDR) 34
5.5.2 1.5% OOP-IDR 35
5.5.3 3.0% OOP-IDR 36
5.6 面外變形之量測結果 37
5.6.1 接合板面外變形 37
5.6.2 圍束段面外變形 37
5.7 穩定性模型預測及分析結果 39
5.7.1 初始缺陷及端部面外位移量 39
5.7.2 分析假設 39
5.7.3 預測及分析結果 40
第六章 WES-BRB多案例穩定性數值分析 42
6.1 容量設計法之設計案例介紹 42
6.2 分析假設 42
6.3 分析結果 44
6.3.1 原設計(接合板加勁) 44
6.3.2 若接合板無加勁之分析 45
6.4 端部面外位移之敏感度分析 45
6.4.1 原設計(接合板加勁) 45
6.4.2 若接合板無加勁之分析 46
第七章 總結與結論 47
7.1 總結 47
7.2 結論 48
參考文獻 50

參考文獻
1.American Concrete Institute (ACI). Building Code Requirements for Structural Concrete and Commentary (ACI 318-14). ACI: Farmington Hills, Michigan, 2014.
2.American Institute of Steel Construction (AISC). Seismic Provisions for Structural Steel Buildings (AISC 341-10). AISC: Chicago, Illinois, 2010.
3.American Institute of Steel Construction (AISC). Specification for Structural Steel Buildings (AISC 360-10). AISC: Chicago, Illinois, 2010.
4.Brace on Demand. User guide for BOD: Buckling restrained braces and connections design procedures. National Center for Research on Earthquake Engineering, Taiwan, 2014.
5.Chuang MC, Tsai KC, Lin PC, Wu AC. Critical limit states in seismic buckling-restrained brace and connection design. Earthquake Engineering & Structural Dynamics 2015; 44(10): 1559-1579.
6.Takeuchi T, Ozaki H, Matsui R, Sutcu F. Out-of-plane stability assessment of buckling restrained braces including moment transfer capacity at restrainer-end. Journal of Structural and Construction Engineering 2013; 78:1621-1630. (in Japanese)
7.Takeuchi T, Ozaki H, Matsui R, Sutcu F. Out-of-plane stability of buckling-restrained brace including moment transfer capacity. Earthquake Engineering & Structural Dynamics 2014; 43(6): 851-869.
8.Takeuchi T, Ozaki H, Matsui R, Sutcu F. Out-of-plane stability assessment of buckling-restrained brace including connections with chevron configuration. Earthquake Engineering & Structural Dynamics 2016; 45(12): 1895-1917.

9.Tsai KC, Hsiao PC, Wang KC, Weng YT, Lin ML, Lin KC, Chen CH, Lai JC, Lin SL. Pseudo-dynamic tests of a full-scale CFT/BRB frame -Part I: Specimen design, experiment and analysis. Earthquake Engineering & Structural Dynamics 2008; 37:1081-1098.
10.Tsai KC, Hsiao PC. Pseudo-dynamic tests of a full-scale CFT/BRB frame -Part II: Seismic performance of buckling restrained braces and connections. Earthquake Engineering & Structural Dynamics 2008; 37:1099-1115.
11.Tsai KC, Wu AC, Wei CY, Lin PC, Chuang MC, Yu YJ. Welded end-slot connection and debonding layers for buckling restrained braces. Earthquake Engineering & Structural Dynamics 2014; 43:1785-1807.
12.Wu, A.C. Lin, P.C. Chuang, M.C. Tsai, K.C. Seismic design and applications of buckling-restrained braced frames. Structural Engineering 2015; 30: 11-33. (in Chinese)
13.Wu AC, Tsai KC, Yang HH, Huang JL, Li CY, Wang KJ, Khoo HH. Hybrid experimental performance of a full-scale two-story buckling-restrained braced RC frame. Earthquake Engineering & Structural Dynamics 2016; 46(8):1223-1244.
14.Yam, M.C.H. & Cheng, J.J.R. Behavior and design of gusset plate connections in compression. Journal of Constructional Steel Research 2002; 58(5–8): 1143-1159.
15.Zaboli B, Clifton C, Cowie K. Out-of-plane stability of gusset plates using a simplified notional load yield line method. NZSEE Annual Technical Conference and 15th World Conference on Seismic Isolation, Energy Dissipation and Active Vibration Control of Structures, Wellington, New Zealand, 2017.
16.陳力維 (2017)，“A Study of Global Out-of-Plane Stability Model for BRBs Incorporating the Flexural Effects of Restrainers” ， 國立臺灣大學土木工程學系結構工程組碩士論文。