新建雙層含鋼板剪力牆之鋼筋混凝土構架耐震設計與實驗研究

Seismic Design and Tests of a Full-scale 2-story RC Frame with Infilled Steel Plate Shear Wall

洪唯竣(Wei-Jun Hung)

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(2016年)

https://doi.org/10.6342/NTU201600466

摘要

鋼板剪力牆為一具高側向勁度、強度、韌性及良好消能性之鋼結構抗側力系統，同時也有重量輕、牆板薄、用鋼量低、樓地板佔用面積小、可穿孔供管線通過、以及受震後可拆換鋼板等優點。以往有關鋼板剪力牆之研究或應用多為鋼結構構架，以型鋼做為邊界梁柱構件。並已有探討利用鋼板剪力牆補強既有鋼筋混凝土構架的研究；若能將鋼板剪力牆應用於新建鋼筋混凝土構架，便能發揮上述優點，替代厚重的磚牆或鋼筋混凝土剪力牆，作為結構主要的抗側力系統，同時降低梁柱斷面尺寸。
本研究以翼外焊有剪力釘之寬翼T形斷面，作為鋼板與鋼筋混凝土邊界梁柱構件的接合介面，T形斷面於灌漿前預埋於邊界梁柱表面，待拆除模板後，便可將鋼板焊接於T形斷面之腹板，使鋼板拉力場能有效傳遞至邊界梁柱。
為了探討該接合方式、鋼板剪力牆應用於新建鋼筋混凝土構架之設計與分析技術，本研究與李宛竹同學合作，設計並製作一座實尺寸兩層樓含鋼板剪力牆鋼筋混凝土構架試體，試體跨距5米，一樓樓高3.11米，二樓樓高3.27米，鋼牆板採用厚度為3.5釐米之LYS200低降伏點鋼板，兩層樓鋼板皆以穿孔的方式折減鋼板的強度，使一樓及二樓鋼板強度分別等效於2.6釐米及1.7釐米之鋼板。由於鋼板拉力場會對邊界構件造成均佈力，本研究以鋼結構鋼板剪力牆習用之疊加法計算邊界構件受力需求，並根據ACI 318-14規範進行邊界構件之容量設計。本試驗選用SAC專案中三種規模大小的地震歷時，於國家地震工程研究中心進行五次擬動態試驗及反覆側推試驗，探討其於真實地震下的耐震性能，以及在極限狀態下的破壞機構。
試驗結果顯示，試體於中小度地震下仍保持彈性，於首次設計地震下最大頂層位移角為0.86%弧度，於首次最大考量地震下最大頂層位移角為1.59%弧度。由於鋼板板條已有殘餘應變，試體於第二次同樣的設計地震規模作用下，有明顯的初始勁度衰減，最大頂層位移角亦達到1.36%弧度，反而在第二次同樣的最大考量地震規模作用下，試體之最大力量及位移反應皆較首次最大考量地震作用下為小。在五次擬動態試驗期間寬翼T形構件無發生明顯之接合破壞。在反覆側推試驗頂層位移角2.2%弧度時，底層上部T形斷面發生剪力釘斷裂而漸發生軟層現象，構架強度發展至2356 kN後未能再向上提升，但二樓鋼板牆至試驗結束前未有明顯接合破壞發生，並於2.75%弧度時發展至最大強度1844 kN，衰退遂漸漸趨緩，至4.5%弧度試驗結束時仍維持相當之強度，整體受力變形反應與鋼結構鋼板剪力牆行為相近，發展出良好之強度及韌性。試驗結果與模擬分析結果吻合，邊界構件塑鉸亦如預期依序發生於中間梁梁端、底層柱柱底及頂層柱柱頂，證實本研究所採用之接合形式可有效連接鋼板與鋼筋混凝土邊界構件，本研究所提出之設計流程亦可有效估算邊界梁柱構件受力需求，使塑鉸發展於預期之位置，以利構架發展出良好的塑性機構。本文並用有限元素ABAQUS模型分析結果，討論T形構件的剪力釘局部受力與破壞關係。

關鍵字

鋼板剪力牆 ； 拉力場 ； 鋼筋混凝土構架 ； 耐震設計 ； 容量設計 ； 擬動態試驗 ； 剪力釘 ； T形斷面

並列摘要

Steel plate shear walls (SPSWs) have been recognized as a high lateral stiffness, strength and ductility lateral load resisting system for steel structures. It has the advantages of light weight, thin wall, perforable for pipeline passing, and replaceable after an earthquake. Past studies on the boundary elements (BEs) in SPSWs were focused on steel sections. Researches of retrofitting reinforced concrete (RC) frames with SPSWs have been reported. SPSWs may provide new RC frame constructions with aforementioned advantages if the steel plates can be appropriately connected to RC BEs.
In this study, WT sections with welded shear stud are utilized as interface of the steel plates and RC frame. WT members were pre-installed on RC BEs before the pouring the concrete. Steel plates can be conveniently welded on the web of WT sections after removing the concrete form work. The WT members with the shear studs must be properly designed in order to allow the panel tension field actions effectively transferred to the RC BEs.
In order to investigate the design, analysis and fabrication methods of the proposed SPSW-RCF, a full scale 2-story SPSW-RCF specimen was designed and fabricated in collaboration with another graduate student, Ms. Wan-Chu Lee. The specimen is 5-meter wide, the story heights are 3.11m and 3.27m for the 1st and 2nd stories, respectively. The 3.5mm-thick LYS200 low yield strength steel plates were adopted. The steel plates in 1st and 2nd story are perforated to a strength equivalent to the 2.6mm-thick and 1.7mm-thick low yield strength plates, respectively. Considering the panel tension filed action, the superposition method used by the design of SPSWs for steel structures is adopted to calculate the BEs force demands. The seismic design of the BEs considers the ACI 318-14 provisions. Three different levels of ground motions adopted in the SAC steel project were selected. Details of the ground motion selections, response predictions, simulations made before and after the tests can be found in the master thesis authored by Ms. Lee. Five pseudo-dynamic tests times were conducted in National Center for Research on Earthquake Engineering, followed by the cyclic loading test. In this report, seismic responses of the SPSW-RCF under realistic earthquake load effects are discussed in detail. The failure mechanism of the SPSW-RCF is analyzed using an ABAQAS finite element model.
Hybrid test results show that specimen stayed essentially elastic under the 50% probability of exceedance in 50 years (50/50) earthquake. Roof drift reached 0.86% rad. under the 10/50 earthquake, and reached 1.59% rad. during the 2/50 event. Due to the residual strains of the steel plates, the SPSW-RCF had a significant drop of initial stiffness during the following 2nd-time 10/50 earthquake , and roof drift reached 1.36% rad. However, the response difference between the following 2nd 2/50 event and the 1st 2/50 earthquake is not much. No obvious failure of the WT member was observed during 5 times of hybrid tests. During the cyclic loading test at a roof drift of 2.2% rad, shear studs fractured in the 1st story top WT member . Frame strength reached a maximum of 2356 kN then decayed rapidly. However, no obvious failure of the 2nd story WT members was observed before the end of cyclic test. Story strength reached 1844 kN at 2.75% rad. and decayed smoothly before 4.5% rad. The experimental lateral force vs. deformation relationships agree well with the predictions, and similar to the all steel framed SPSW responses. Tests confirm that the proposed design and fabrication methods for the WT sections can effectively transfer the forces from the steel plates to the RC BEs. The proposed design procedures can accurately estimate the combined force demands, due to the panel force and frame action effects, imposed on the RC Bes. Tests confirm that the locations and the forming sequence of the plastic hinges are accurately predicted. The report also uses ABAQUS finite element model to discuss the local force demand and connection failure at the 1st story top WT member. The design implications are provided accordingly.

並列關鍵字

steel plate shear wall ； reinforced concrete frame ； seismic design ； capacity design ； hybrid test ； shear stud ； WT member

參考文獻

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