實尺寸兩層樓挫屈束制支撐子結構雙向受震擬動態試驗與分析

Pseudo Dynamic Tests and Analysis of A Full Scale Two-story Steel Buckling Restrained Braced Substructure under Bi-directional Earthquake Loads

蔡政育(Cheng-Yu Tsai)

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(2005年)

https://doi.org/10.6342/NTU.2005.00823

摘要

近幾年來有關挫屈束制支撐(BRB)之研究，均證實此種消能斜撐為一種十分有效的耐震消能元件。因其在受壓時並不會產生挫屈的現象，所以在反覆加載之下可以產生飽滿的遲滯迴圈行為，而能消散大量的能量。因此近幾年來在台灣、日本與美國此種斜撐皆已漸受廣泛的採用。但在過去的這些研究當中，往往是以單軸拉壓的方式進行挫屈束制支撐構件試驗，而在整體構架試驗結果方面仍顯不足。此外，由在2003年於國家地震工程研究中心所進行的實尺寸三層樓之挫屈束制支撐CFT/BRB構架試驗，可得知接合板若依習見設計方法而不採適當的加勁將有可能發生挫屈。因此為進一步研究接合板的耐震設計方法並考慮真實結構物受雙向地震作用下之受力與變形對接合板的效應，本研究進行一座實尺寸二層挫屈束制支撐構架雙向受震之擬動態子結構試驗。
本研究探討挫屈束制支撐與其接合在結構中之行為外，亦探討網路子結構擬動態實驗技術。而本研究的主要項目有：1)探討整體構架之耐震設計方法，比較試驗所得與數值分析的結果。2)檢討挫屈束制支撐於構架中之耐震行為，包括斜撐消能情形、斜撐累積塑性韌性表現、斜撐端部轉角與斜撐韌性等。3) 探討接合板之耐震行為與ABAQUS有限元素分析結果，包括接合板之設計方法、側向變形計算方法。試驗顯示斜撐之接合板在經過加勁後，歷經三組不同危害度(50年超越機率分別低於50%, 10% 與2%)之雙向地震歷時後，構架中完全無挫屈或其他的明顯破壞現象產生，驗證有限元素分析及所提設計方法的可用性，試驗結果顯示可使用有效長度係數K=1.0 於Whitmore與Thornton之方法來設計加勁後之接合板。挫屈束制支撐於構架中行為表現良好，幾乎承受全部樓層剪力之外，一樓BRB之累積塑性韌性CPD值已超過140。

關鍵字

挫屈束制支撐 ； 構架 ； 擬動態試驗

並列摘要

In recent years, several researchers have confirmed that buckling restrained brace (BRB) is a very effective energy dissipation element to reduce seismic responses of building structures. It has been shown in many research laboratories that BRB components can sustain large cyclic inelastic strain reversals and stably absorb a significant amount of energy without failure. Thus, buckling restrained braced frame (BRBF) has gained wide acceptance in Japan, Taiwan and North America. While most of the BRB tests have confirmed the excellent performance of the BRB component in absorbing energy, recent pseudo dynamic tests conducted in October 2003 in the National Center for Research on Earthquake Engineering (NCREE) on a full scale three-story BRBF has revealed the importance of the gusset plate details. Gusset plates designed according to the conventional methods may not require any gusset edge stiffener, but could be buckled under large BRB compressive forces. In order to further investigate the gusset plate design methodology, a full scale two-story BRBF is tested in NCREE in this study using substructure pseudo dynamic test procedures and considering bi-directional earthquake load effects of three different seismic hazard levels.
The objectives of this study include: 1) investigate the current and modified design criteria of the BRB gusset plate subjected to axial load and out-of-plane bending, 2) conduct the ABAQUS finite element analysis to investigate the buckling strength of the gusset plate details adopted in the 2-story BRBF specimen, 3) incorporate the Platform for Inelastic Structural Analysis for 3D System (PISA3D) into the servo-control loop for substructure hybrid tests, 4) provide seismic design recommendations for the BRB gusset plate subjected to bi-directional force and deformations.
Test results showed that the 2-story BRBF specimen can be very effectively tested by using the substructure pseudo dynamic test procedures, particularly with real-time webcasting of test results. The 2-story BRBF specimen sustained three sets of ground accelerations (scaled to represent less than 50%, 10% and 2% chance of exceedance in 50 years) without any sign of strength of stiffness degradation. It is found from the tests that the out-of-plane deformational demand imposed on the gusset plates can be satisfactorily estimated by linear interpolation of the inter-story drift considering the dimension of the gusset plate with respect to the story height. It is confirmed from the test and ABAQUS analysis results that after adding the gusset plate edge stiffeners, an effective length factor of K=1.0 can be incorporated into the Whitmore and Thornton methods for the design of gusset plates.

並列關鍵字

Buckling Restrained Brace ； Pseudo Dynamic Tests

參考文獻

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