Abstract
This paper examines the application of BRB in strengthening of reinforced concrete frame structures to meet seismic requirements according to Chinese seismic design code. Elastic response spectrum analysis and nonlinear time history analysis are performed by taking a real engineering example that suffers weak first floor irregularity due to added loads and addition of one floor. With the method of equivalent stiffness and displacement-based design method, buckling restrained brace parameters are deduced and are used to model BRB in ETABS using plastic wen model. Three configurations of buckling restrained braces are studied together with ordinary braces. Under elastic state, the relationship between the required cross section area of BRB and ordinary braces is deduced from the formula of calculating elastic bearing capacity where it is shown that the area of the ordinary braces must be 1.25 times that of BRB for ensuring the same performance. The results show that Inverted V brace configuration demonstrated better performance over single brace and V brace configurations and X brace configuration, although not recommended by Chinese code, is simulated and used in this paper and has demonstrated better performance over other configurations, and the further research on the practical use of this brace is recommended. Also, under action of strong earthquakes, by nonlinear time history analysis, buckling restrained braces demonstrated better performance of strengthening the structure and make it meet the requirement of code. Under this same condition, ordinary braces losses their bearing capacity due to excessive buckling.
Highlights
Located between the Eurasian seismic belt and the circum-Pacific seismic belt, China is one of the countries with the largest number of earthquakes in the world and one of the countries with the greatest loss due to earthquake disasters because of its complex geological structure and frequent seismicity [1]
Second and third mode of vibration respectively According to elastic response spectrum analysis results, it is found that the frame structure will suffer from weak first story which lead to concentrated deformation to the first story with the horizontal stiffness that does not conform to the Chinese standard GB50011-2010
Analysis Results of Strengthened Engineering Model The strengthened building was analyzed by response spectrum analysis under the same loading conditions as the original frame, and the following response characteristics are obtained
Summary
Located between the Eurasian seismic belt and the circum-Pacific seismic belt, China is one of the countries with the largest number of earthquakes in the world and one of the countries with the greatest loss due to earthquake disasters because of its complex geological structure and frequent seismicity [1]. The research on the application of BRB in frame structures have shown that buckling restrained braces yield ductility in both compression and tension, they characterized by a full, stable and symmetric hysteretic loop with relatively low yield stiffness [5] These two kinds of braces have been studied intensively in design of frame structures, their application in strengthening of reinforced frame structures against lateral and vertical loads is still not fully studied. Significant increase in strength, deformation and energy dissipation capacity of reinforced concrete building structures due to inclusion of BRB was confirmed by Andre Almeida et al [13] in their research conducted by taking pre-code building structure These are seismic characteristics that are important in limiting damage in the original structural elements. Assessment of nonlinear seismic response characteristics of the structure after reinforcement by nonlinear time history analysis under strong earthquakes according to GB50011-2010
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
