鋼造自復位挫屈束制斜撐（SC-SBRB）發展及耐震試驗

Development and Seismic Tests of Steel Self-Centering Sandwiched Buckling-Restrained Braces (SC-SBRBs)

周中哲(Chung-Che Chou) ； 蔡文璟(Wen-Jing Tsai) ； 鍾秉庭(Ping-Ting Chung)

《結構工程》 34卷1期 (2019/03) Pp. 57-76

https://doi.org/10.6849/SE.201903_34(1).0003

摘要

鋼造斜撐構架具有良好的耐震性能，然而在大變形下易使建築物產生結構損壞和殘餘變形，造成震後難以修復且費用昂貴，因此本文提出一種可提升建築物抗震能力的全新鋼造自復位挫屈束制斜撐（Self-Centering Sandwiched Buckling-Restrained Brace，SC-SBRB），此種斜撐同時具有雙核心自復位斜撐的自復位能力及挫屈束制斜撐的消能能力，自復位能力是利用斜撐中的兩組拉力構件束制斜撐中的鋼受壓構件，使斜撐在大變形下具有回到零殘餘變形的能力；消能能力是利用兩組獨立分離的圍束構件以栓接方式束制斜撐中的核心構件，使得斜撐受壓不會挫屈而產生飽滿的遲滯消能。本文首先介紹兩組不同構件配置的自復位挫屈束制斜撐，說明其力學行為及抗震機制，以減少建築物受震的最大變形及殘餘變形，並於實驗室進行兩組長度7860mm的實尺寸斜撐試驗驗證其耐震性能，試驗結果顯示斜撐的傳力機制與理論預測相符，試驗亦證明兩組斜撐試體分別經歷共3次反覆載重及52圈疲勞載重測試下仍保持良好耐震能力，斜撐更可在層間側位移角2.5%而不破壞，最大軸力可達1700kN，全部試驗的累積韌性容量可達1090－1129，超過美國耐震規範AISC（2010）的建議值200。

關鍵字

自復位挫屈束制斜撐 ； 反覆載重 ； 殘餘變形 ； 能量消散

並列摘要

Earthquake-resisting frame systems that are designed based on current seismic provisions provide life safety performance in a large earthquake, but may have significant structural damage or residual drift due to energy dissipation in designated structural members. The damage leads to difficult or expensive repairs after a large earthquake. Therefore, development of a structural system that has both energy dissipation and self-centering properties in earthquakes is needed to improve the seismic performances of buildings. This paper presents a viable solution that was validated by multiple cyclic tests of an innovative brace, called a dual-core self-centering sandwiched buckling-restrained brace (SC-SBRB). The proposed brace combines the self-centering property of a dual-core self-centering brace (DC-SCB) and the energy dissipation of a sandwiched buckling-restrained brace (SBRB) together. The dual-core SC-SBRB is essentially a DC-SCB that is positioned concentrically with a SBRB to create both the self-centering and energy dissipation properties in either tension or compression. A 7860 mm-long dual-core SCSBRB, which uses ASTM A572 Gr. 50 steel as bracing members and ASTM A416 Grade 270 steel tendons as tensioning elements, was cyclically tested six times to validate its kinematics and cyclic performance. The test program demonstrated that the proposed dual-core SC-SBRB provides stable hysteretic responses with appreciable energy dissipation, self-centering behavior and large deformation capacity before low-cycle fatigue failure of the SBRB core.

並列關鍵字

Self-centering sandwiched buckling-restrained brace (SC-SBRB) ； Cyclic test ； Residual deformation ； Energy dissipation