Buckling mechanism of steel core and global stability design method for fixed-end buckling-restrained braces

2018 ◽  
Vol 174 ◽  
pp. 447-461 ◽  
Author(s):  
Junkai Lu ◽  
Bin Wu ◽  
Yang Mei
2014 ◽  
Vol 24 (4) ◽  
pp. 243-256 ◽  
Author(s):  
Do-Hyun Kim ◽  
Chang-Hwan Lee ◽  
Young K. Ju ◽  
Sang-Dae Kim

2016 ◽  
Vol 691 ◽  
pp. 195-206
Author(s):  
Juraj Frólo ◽  
Štefan Gramblička

This paper presents some results of theoretical and experimental investigations of composite steel-concrete columns with solid steel profiles - steel cores. Due to absence of simplified design method according to EN 1994-1-1 [1], design of these columns in practice is limited in general. Reasons for this are residual stresses in steel profile caused by fabrication process and limitation of strains in concrete. Recommendations have been determined for simplified design method according to EN 1994-1-1 for composite columns made of high strength concrete filled steel tube with central steel core. Results of experimental research on composite columns with the cross-section made of steel core covered by reinforced concrete are presented.


2019 ◽  
Vol 15 (10) ◽  
pp. 155014771988135
Author(s):  
Yanchao Yue ◽  
Tangbing Chen ◽  
Yongtao Bai ◽  
Xiaoming Lu ◽  
Yan Wang ◽  
...  

Buckling-restrained braces play a critical role as the first-defendant line in dissipating seismic energy and are often used in concrete frame structures to ensure that the main beam–column members are “undamaged” or significantly elastic during medium earthquakes. The design of the reinforced concrete frame structures with buckling-restrained brace is generally based on the assumption of shear deformation of the structure. The conventional seismic design considers the “second-defendant line design” based on the geometric relationship between the axial deformation and strength of buckling-restrained braces and stratified deformation. This article proposes iterative optimization of the buckling-restrained brace design method and layout scheme based on the nonlinear structural response of the calibrated numerical model, and then approximates the nonlinear structure scheme using a linear method. Time history analyses are performed to prove that the linear design method is highly conservative for estimating seismic intensity, and the proposed design method provides more efficient damage distributions in frame components. The results of the nonlinear performance evaluation and energy analysis indicate that the method proposed in this article can meet the performance design requirements achieving multi-performance criteria.


2018 ◽  
Vol 763 ◽  
pp. 916-923
Author(s):  
Ben Sitler ◽  
Toru Takeuchi ◽  
Ryota Matsui

Buckling-restrained braces (BRBs) achieve large peak and cumulative ductility capacities by restricting yielding to an encased core, while maintaining global stability. However, stability is often governed by the connections and is sensitive to the end fixity provided by the adjacent framing and gusset, and flexural continuity between the neck and restrainer. This paper presents simple analytical methods to determine the flexural properties of these key components. Full-depth gusset stiffeners are found to be highly effective in increasing the out-of-plane rotational stiffness (KRg), equivalent to doubling the thickness. An equivalent connection is proposed to account for the adjacent framing (KRf), but this may be neglected if KRf > 10∙KRg. This is typically satisfied if a diaphragm slab and transverse beam are provided, but may exceed beam torsional bracing requirements. The restrainer end moment transfer capacity is extended to mortar-filled RHS restrainers, confirming that neck insert ratios of Lin/Bn > 2.0 are required for full continuity.


2019 ◽  
Vol 20 (1) ◽  
pp. 185-204
Author(s):  
Yongqing Fan ◽  
Wenqing Wang ◽  
Xiangkui Jiang ◽  
Zhen Li

Abstract A decentralized adaptive control based on human linguistic is investigated to learn human behaviors for multiple robotic manipulators. Many experts’ words or sentences can be transferred into the control actions by employing membership functions in robot systems, which can be synthesized fuzzy controller by employing reasoning mechanism. For the unknown model dynamical robot manipulators, one adjustable parameter that relates to the approximation accuracy of fuzzy logic systems is introduced at first, which be utilized to deal with the unknown dynamics of robot manipulators. Switching fuzzy adaptive controller is designed to overcome the limitation of logic structure that the number of adaptive laws only focus on fuzzy rules in conventional fuzzy logic systems. Another advantage of this design method is that the control with human linguistic extend the semi-global stability to global stability. Finally, effectiveness of the developed control design scheme has been shown in simulation example.


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