鋼板剪力牆邊界柱構件耐震設計研究

A Study of Capacity Design for Vertical Boundary Elements in Steel Plate Shear Walls

李弘祺(Hung-Chi Lee)

指導教授 ： 蔡克銓

國立臺灣大學/工學院/土木工程學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.02539

摘要

鋼板剪力牆系統具有高側向勁度與韌性的系統，但此系統在國內工程實例上的應用仍不多見，主要原因可能為：一、邊界構件的容量設計常須透過複雜的板條模型完成，二、根據AISC規範，邊界柱塑鉸只能產生在柱底，因此對於底層柱的撓曲需求會非常大，將造成邊界柱尺寸非常保守的設計。為了要針對鋼板剪力牆系統底層邊界柱發展一套簡便的容量設計方法，本研究採用等效斜撐模型搭配計算公式。此外為了讓底層柱在無安全疑慮下尺寸更精減，本研究允許柱底塑鉸至四分之一底層柱高，但限制柱頂沒有撓曲及剪力塑鉸作為設計準則並推導設計方法。
為了驗證本研究所考慮的容量設計方法在預測底層邊界柱塑鉸位置的精準度，以及觀察鋼板剪力牆底層邊界柱柱頂有或無塑鉸時的行為，本研究於國家地震工程研究中心完成了三座兩層樓鋼板剪力牆的反覆側推試驗，並進行試體的有限元素模型分析。試體的跨距為3.42米而每層高為3.82米，寬高比為0.9，三座試體鋼板使用2.7mm厚的低降伏強度鋼板，並採用相同的邊界梁設計，而以不同的設計準則設計三種不同尺寸的邊界柱。
試驗與有限元素模型分析結果證實本研究所採用的容量設計方法在預測底層邊界柱的塑鉸位置上有相當的準確度，而底層柱跨中產生塑鉸並有大範圍降伏的鋼板剪力牆系統仍具有相當飽滿的遲滯迴圈反應，反之底層柱在柱四分之一高及柱頂同時產生塑鉸的邊界柱，則觀察到有嚴重的側向扭轉挫屈發生，是工程應用上該避免的設計結果。此外，試驗的結果也顯示拉力場的角度會因邊界構件由彈性進入塑性而改變，由於有大量的塑性變形發生在底層邊界柱跨中導致柱軟化，因此底層拉力場角度會接近40度，對於二樓而言，由於塑性變形集中在邊界梁上而邊界柱近乎保持彈性，此時拉力場角度會接近45度。

關鍵字

鋼板剪力牆 ； 容量設計 ； 耐震設計 ； 邊界柱構件 ； 拉力場角度

並列摘要

Steel Plate Shear Walls (SPSWs) have been recognized as a high lateral stiffness and ductility system for building structures. However, this system is still not commonly adopted in practice. It may be due to the following two reasons: 1) The capacity design of the boundary elements must be checked by using strips model, which may be complicated and time-consuming. 2) The column plastic hinge must be formed only at the 1st story column bottom end according to the AISC provisions. Therefore the flexural requirement for the 1st story column may be very large. For the purpose of developing a convenient capacity design method for the 1st story columns in the SPSWs, the equivalent brace model is considered in formulating the design procedures. Allowing the plastic zone to form approximately at 1/4-high of the first-story column, this study purposes a minimum column flexural capacity design requirement to prevent both the flexural and shear plastic hinges form at the top of the 1st story column.
In order to verify the accuracy the proposed capacity design method, and to investigate the cyclic performance of the SPSWs with or without the plastic forming at the top of the 1st story column, three full-scale 3.42-meter wide and 3.82-meter high two-story SPSW specimens were tested in National Center for Research on Earthquake Engineering. The low yield strength steel plates of 2.7mm and the same boundary beams, but with the boundary columns designed according to three different flexural requirements, were adopted for three specimens. Results of the ABAQUS analyses and the cyclic tests up to a roof drift of 0.045 radians confirm that the proposed capacity design method is suitable for seismic design of 1st story column to achieve good performance and economy. The 1st story column with plastic deformations spreading over mid-high of the column still possesses rather good load-carrying capacity. However, the specimen with plastic hinges forming at the mid-high and the top of the 1st story column have seriously lateral torsional buckling. In addition, test results show the tension field angle changes from boundary elements elastic to plastic. For the 1st story, due to large plastic deformation in the mid-high of boundary columns, the tension field angle inclines to approximately 40 degree. For the 2nd story, however, the plastic deformation concentrates at on boundary beams, so the tension field angle inclines near 45 degree.

並列關鍵字

steel plate shear walls ； capacity design ； seismic design ； vertical boundary elements ； tension field angle

參考文獻

21. 朱駿魁 (2010), 「多樓層鋼板剪力牆結構耐震分析與設計之研究」，國立台灣大學土木工程學系結構組碩士論文。

22. 林志翰 (2005), 「實尺寸兩層樓鋼板剪力牆子結構擬動態試驗與分析」，國立台灣大學土木工程學系結構組碩士論文。

23. 林盈成 (2004), 「低降伏強度鋼板剪力牆之耐震行為研究」，國立台灣大學土木工程學系結構組碩士論文。

1. AISC (2005), Specification for Structural Steel Buildings, American Institute of Steel Construction, Chicago, IL.

2. AISC (2005), Seismic Provisions for Structural Steel Buildings, American Institute of Steel Construction, Chicago, IL.