三維鋼板剪力牆耐震設計研究

Research on Seismic Design of Three Dimensional Steel Plate Shear Walls

楊依璇(Yi-Hsuan Yang)

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(2014年)

https://doi.org/10.6342/NTU.2014.01861

摘要

鋼板剪力牆為一具高側向勁度與韌性之新型鋼結構抗側力系統。以往有關鋼板剪力牆邊界梁構件之研究或使用，多採鋼寬翼斷面，由於實際建築結構中常有樓板存在，對於僅承受鋼板下拉力之頂層邊界梁，梁跨中承受大量正向彎矩，若可考量以鋼寬翼斷面與混凝土樓板之合成梁應用於鋼板剪力牆之邊界梁中，則混凝土之抗壓性質應能對梁之正向彎矩強度提供一定貢獻，使梁斷面的選擇更為經濟。因此本研究以ABAQUS有限元素分析觀察合成梁應用於鋼板剪力牆邊界梁之行為，分析結果顯示，來自合成梁下方之鋼板拉力，會使混凝土與鋼梁之共同作用行為不如預期，在鋼梁達極限狀態時，混凝土提供的強度甚是微小。因此本研究建議不宜以合成梁設計邊界梁，而應保持一般鋼寬翼斷面梁之設計方法，僅考量鋼骨之彎矩強度。
在建築結構中，一般針對不同向的地震分別設計結構物雙向的抗側力系統，若將用以抵抗不同側向地震力之鋼板剪力牆組合為三維鋼板剪力牆系統，並將之應用於樓梯或電梯隔間，則鋼板剪力牆在建築結構中將有更好的使用性。本研究先以較為簡便的等效斜撐模型設計鋼板剪力牆系統，對承受雙向反應之三維鋼板剪力牆底層邊界柱構件進行研究，考量雙正交向構架及鋼板造成之彎矩、剪力及軸力互制關係，提出一套三維鋼板剪力牆邊界柱容量設計方法。為驗證所提方法之有效性，本研究採五組兩層樓L型三維鋼板剪力牆有限元素模型進行分析，分析結果顯示，本研究所提出之算式可準確預估底層受壓邊界柱之雙向彎矩需求分佈。
為了驗證並觀察三維鋼板剪力牆實際受雙向側推之反應，本研究與黃彤同學合作，設計一座實尺寸兩層樓C型三維鋼板剪力牆試體，並於國家地震工程研究中心進行雙向反覆側推試驗，由試驗過程記錄及反應來探討鋼板剪力牆系統底層柱之塑性行為。試體長向為跨距5米之一般型鋼板剪力牆，短向為跨距2米之束制型鋼板剪力牆，樓層一樓高為3.41米、二樓為3.28米。試體使用2.6公厘厚的低降伏強度鋼板，為配合油壓作動器之容量限制，二樓鋼板進行穿孔，強度折減至等效於1.8公厘厚之鋼板。反覆側推試驗至+2.5%弧度之試驗結果及ABAQUS有限元素側推分析證實，本研究提出之三維鋼板剪力牆邊界柱設計方法可準確預估底層受壓邊界柱之耐震實驗反應。

關鍵字

鋼板剪力牆 ； 束制型鋼板剪力牆 ； 合成梁 ； 耐震設計 ； 容量設計 ； 雙向地震 ； 軸彎互制

並列摘要

Steel plate shear walls (SPSWs) have been recognized as a steel structural system with high lateral stiffness and ductility. Past studies on the horizontal boundary elements(HBEs) in SPSWs were focused on the steel wide flange sections. Due to the panel tension filed action, the top boundary beam in a SPSW is subjected to a positive bending moments near the beam mid-span, since concrete slab exists in building structures, the composite action of the concrete slab and steel beams may reduce the requirements of the steel beams size. In order to investigate the effects of composite action in the top boundary beam of SPSW, ABAQUS finite element model (FEM) analysis is conducted. Analysis results show that the composite effect is not pronounced since the vertical downward panel forces are applied on the beam bottom flange. The concrete slab only provides a small contribution on the positive bending moment capacity when the steel beam reaches the ultimate state. Therefore, it is concluded that only the steel section without the composite action be considered in the design of the top HBEs.
The lateral force resisting systems in building structures are usually designed separately for two orthogonal directions. The three dimensional steel plate shear wall (3D-SPSW) systems can be configured by using more than one SPSW in two different directions. It could be constructed around the stair or elevator cases in a building to resist the biaxial lateral forces effectively. In this study, the equivalent brace models are incorporated into a simplified procedures to estimate the biaxial force demands in the 1st story column of a 3D-SPSW. The proposed capacity design method for the column considers the relationships among the axial force, biaxial bending moments and shear induced from both the frame and panel actions. In order to examine the effectiveness of the proposed capacity design method, ABAQUS FEM analyses of five 2-story L-type 3D-SPSWs systems are conducted. Analytical results confirm that the biaxial moment distribution in 1st story column can be accurately estimated by the proposed design method.
In order to investigate the seismic responses of the 3D-SPSW under the biaxial earthquake load effects, a full scale 2-story C-type 3D-SPSW specimen was tested in National Center for Research on Earthquake Engineering in collaboration with another graduate student, Mr. Huang Tung. In the longitudinal direction, it is a typical 5-meter wide SPSW, while in the transverse direction, there are two 2-meter wide restrained SPSWs. The story heights are 3.41m and 3.28m for the 1st and 2nd stories, respectively. The 2.6mm-thick low yield strength steel plates were adopted. In order to match the force capacity of the actuators, the steel plates in 2nd story are perforated to a strength equivalent to a 1.8mm-thick low yield strength plate.
Results of the pushover analyses on FEMs and the cyclic loading tests up to a roof drift of 0.025 radians confirm that the proposed capacity design method are suitable for the seismic design of 3D-SPSWs. The nonlinear responses of the 1st story column can be accurately predicted by the proposed design procedures.

並列關鍵字

steel plate shear walls ； restrained steel plate shear walls ； composite beam ； seismic design ； capacity design ； biaxial earthquake forces ； axial and flexural interaction

參考文獻

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