新建含挫屈束制支撐之實尺寸兩層樓鋼筋混凝土構架耐震設計、試驗與分析研究：二、試驗結果與模擬分析

Seismic Design, Tests and Analysis of a Full-scale Two-story Reinforced Concrete Frame with Buckling-restrained Braces - Part II: Test Results and Response Analysis

楊巽閎(Hsun-Horng Yang) ； 黃潔倫(Jie-Luen Huang) ； 吳安傑(An-Chien Wu) ； 李昭賢(Chao-Hsien Li) ； 蔡青宜(Ching-Yi Tsai) ； 王孔君(Kung-Juin Wang) ； 蔡克銓(Keh-Chyuan Tsai)

《結構工程》 31卷2期 (2016/06) Pp. 115-136

https://doi.org/10.6849/SE.201606_31(2).0006

摘要

在第一篇中已詳細介紹雙層含挫屈束制支撐（buckling-restrained brace, BRB）鋼筋混凝土（reinforced concrete, RC）構架（BBR-RCF）之設計與預測分析，本篇則討論BRB-RCF 之試驗觀察、試驗與模擬分析結果。試驗結果顯示，在50/50 級地震作用下，一樓及二樓BRB最大水平剪力分別占整體構架水平剪力之52%與71%；在10/50 與2/50 級地震時，則分別為60%與70%，證實BRB 能提供整體構架良好側向勁度與強度。四次擬動態試驗中，各層遲滯能量消散比例介於60%至94%，證實BRB 能消散大部份的地震能量。反覆載重試驗完成2.75%層間側位移（inter-story drift ratio, IDR）的加載時，一樓與二樓BRB之總累積塑性變形量已分別超過476與680。當反覆載重試驗進行至試體IDR達3.5%時，側向強度仍未下降，且維持穩定的遲滯消能行為。進行至IDR為4.5%時，一樓上端接合板才發生挫屈，但亦導致一樓BRB圍束鋼管發生整體撓曲挫屈。當一樓頂接合板之有效長度因子K_(cr)採2.0計算時，需求與強度比（demand-to-capacity ratio, DCR）將達1.05，且一樓BRB圍束鋼管之設計DCR已高達0.95，顯示接合板挫屈後牽動BRB圍束鋼管發生整體撓曲挫屈，試驗與此分析結果相符。試驗結果顯示，本研究所提之鐵件施工與設計方法可行，在試驗程中保持彈性，並證實所採RC構件不連續區域之設計方法能避免破壞發生，可供工程應用參考。由於預測模型高估10/50及2/50地震等級下之反應，本篇詳述利用試驗反應進一步校正PISA3D分析模型之方法，模擬結果大幅提高分析模擬於2/50等級地震下之準確度。

關鍵字

鋼筋混凝土結構 ； 挫屈束制支撐 ； 預埋鐵件 ； 擬動態試驗 ； 接合板挫屈 ； 非線性分析

並列摘要

Seismic design and analytical response predictions of the full-scaled two-story BRB-RCF are introduced in the Part I paper. This Part II paper discusses the experimental observations, test results and analytical simulations using a refined PISA3D model. In the 50/50 earthquake, the ratios of peak BRB and BRB-RCF shear are 52% and 71% for the first and second stories, respectively. Similar ratios can be obtained if a factor 0.7 is applied on the gross moment of inertia for RC members in the ETABS elastic model. In the 10/50 and 2/50 events, the ratios become about 60% and 70% for the first and second stories, respectively. These indicate that BRBs can provide a high lateral stiffness and strength. The hysteresis energy dissipated ratios in the four hybrid tests are ranging from 60% to 94% for the two stories, confirming that BRBs can effectively dissipate seismic input energy. When the 2.75% inter-story drift ratio (IDR) cycles were completed during the cyclic loading test, the cumulative plastic deformations were more than 476 and 680 for the first- and second-story BRBs, respectively. When both two stories reached an IDR of 3.5%, the frame's lateral force versus deformation response was still very stable. Up to the first IDR=4.5% loading cycle, the first story top gusset buckled, caused the subsequent flexural buckling of the first story BRB to occur. This is consistent with the predicted results as this gusset's demand-to-capacity ratio DCR is 1.05 for the buckling limit state when the effective length factor K_(cr)=2.0 is considered. Nonetheless, the buckled BRB have a DCR=0.95 in the steel casing. No failure of the steel embedment is observed in the tests. Test results confirm that the ACI provisions and the simplified softened strut-and-tie model can be effectively applied to prevent the RC discontinuity region failure. This study demonstrates that the proposed design and construction methods for the steel embedment are effective and practical for the real applications. The response analysis of the refined PISA3D model calibrated from using the test results is conducted to demonstrate the accuracy enhancement compared to the typical model.

並列關鍵字

reinforced concrete frame ； buckling-restrained brace ； steel embedment ； hybrid test ； gusset buckling ； nonlinear analysis