The Longitudinal Seismic Analysis of Single-Story and Single-Span Gabled Frame Structures

2015 ◽  
Vol 744-746 ◽  
pp. 335-339
Author(s):  
Hong Dong Ran ◽  
Le Chen ◽  
Yun Mei Ma
Keyword(s):  
Seismic Analysis ◽  
Time History ◽  
Steel Structure ◽  
National Standard ◽  
Nonlinear Time History Analysis ◽  
Frame Structures ◽  
Seismic Action ◽  
Light Weight ◽  
Standard Design ◽  
Nonlinear Time History

Four single-story single-span Gabled Frame Structures (GFSs) which included in China national Standard Design Drawing of Light-weight Steel Structure with Gabled Frame (02SG518-1) were studied and their longitudinal seismic performances were evaluated through extensive nonlinear time-history analysis using eight ground motions representing the Frequent Earthquake, DBE and the MCE hazard levels, the load-bearing performances, deformation capacities and the curves of displacement were studied. The analysis results showed that the longitudinal seismic action of all GFSs considered in this study is very little, the displacement at the top of the column can satisfy the demands of the Technical Specificationfor Steel Structure of Light-weight Building with Gabled Frames even in MCE. The GFSs designed followed the Specificaiton have the excellent longitudinal seismic performance.

Seismic Performance of the Reinforced Concrete Frame Structures with Infilled Walls of Different Configuration

2014 ◽  
Vol 580-583 ◽  
pp. 1458-1462
Author(s):  
Min Sheng Guan ◽  
Hong Biao Du ◽  
Wei Chen ◽  
Yu Hua Wu
Keyword(s):  
Reinforced Concrete ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Mode Analysis ◽  
Frame Structures ◽  
Seismic Action ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
Reinforced Concrete Frame Structures ◽  
Nonlinear Time History

Using the three-strut model, five types of frame structures, i.e., without infilled walls, with full infilled walls, without bottom-storey infilled walls, without middle-storey infilled walls and without top-storey infilled walls, were studied. The mode analysis and nonlinear time-history analysis were carried out on each model. In order to investigate the effects of infilled walls with different configurations on the seismic behavior of reinforced concrete frame structures, the structural periods, the ratio of Tt to T1 and the maximum interstorey drifts were analyzed. The results indicate that the infilled walls enhance the lateral stiffness of frames, and the configuration of infilled walls has little influence on the calculation of structural periods. It also shows that the weaker storey is formed due to the unreasonable layout of infilled walls, thus leading to the collapse of the whole structures under the seismic action.

Nonlinear Analysis of a RC Frame Structure with Semi-Interlayers Damaged during Wenchuan Earthquake

2010 ◽  
Vol 156-157 ◽  
pp. 467-472
Author(s):  
Peng Tao Yu ◽  
Jing Jiang Sun
Keyword(s):  
Nonlinear Analysis ◽  
Wenchuan Earthquake ◽  
Time History ◽  
Large Earthquake ◽  
Frame Structure ◽  
Nonlinear Time History Analysis ◽  
Frame Structures ◽  
Rc Frame ◽  
Rc Frame Structures ◽  
Nonlinear Time History

Under the excitation of large earthquake, structures enter into high nonlinear stage. Currently, Opensees, Perform-3d and Canny are used as the most popular nonlinear analysis procedures. The fiber model will be introduced firstly and the nonlinear analysis models in Canny are explained in detail. Then Canny2007 is used to conduct nonlinear time history analysis on a heavily damaged frame structure with interlayer in Dujiangyan during Wenchuan Earthquake. Analysis shows that the maximum inter-story drift appears between the interlayer and its upper layer, and the heavy damage agrees well with the results of damage investigation. By comparing the damage extent of frame structures with or without interlayer, it reveals that the seismic performance of RC frame structures without interlayer is obviously better than that of ones with interlayer.

Study on Methods for HCLPF Value of Nonlinear Supports System of Steam Generator

2018 ◽  
Author(s):  
Feng-chun Cai ◽  
Xian-hui Ye ◽  
Qian Huang ◽  
Wenzheng Zhang
Keyword(s):  
Steam Generator ◽  
Nonlinear Model ◽  
Seismic Analysis ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Cost Calculation ◽  
Seismic Capacity ◽  
Ground Acceleration ◽  
Reactor Building ◽  
Nonlinear Time History

High confidence of low probability of failure (HCLPF) values of equipment, representing the seismic capacities of the equipment, are the fundamental ingredient in seismic probability safety assessment (SPSA) and seismic margin analyses (SMA). In this paper, two methods for calculating the HCLPF values of equipment were investigated, fragility analysis, and conservative deterministic failure margin (CDFM). These methods are linear methods. Based on these methods, HCLPF value of equipment can be computed conveniently by scaling the results of the existing seismic analysis. For a nonlinear systems, the HCLPF values based on these linear scaling methods are unrealistic. For a complicated nonlinear equipment or structure, a detail nonlinear model was used to derive the seismic capacity. The results by this method are realistic, but cost calculation time. In this paper, a nonlinear model of reactor coolant system coupled reactor building was built. This model includes the steam generator and considers the nonlinear factors of steam generator such as gap in the supports, plasticity of hot leg and cold leg. Forced motion was applied to the base of reactor building. And seismic response of the steam generator was calculated iteratively by scaling the ground motion level step by step. Based on these calculations, a curve of load on the supports VS peak ground acceleration (PGA) can be obtained. Then based on these curves and allowable load of supports of steam generator, which derived from stress analysis on support of steam generator, seismic capacity of the supports of steam generator was determined. Then the HCLPF Value of the supports of steam generator was obtained by this nonlinear time history analysis and was compared with the results based on the CDFM. The two results were different. Therefore, the HCLPF seismic capacity of equipment with nonlinearity, such as gap nonlinearity, should be calculated by nonlinear time history method.

scholarly journals Investigating the Performance of Viscoelastic Dampers (VED) Under Nearfield Earthquakes with Directivity Feature

2018 ◽  
Vol 14 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Ali Vatanshenas ◽  
Mohammad Sadegh Rohanimanesh ◽  
Ehsan Mohammadiha
Keyword(s):  
Short Distance ◽  
Near Field ◽  
Time History ◽  
Steel Structure ◽  
Nonlinear Time History Analysis ◽  
Acceleration Response ◽  
Viscoelastic Dampers ◽  
Acceleration Time History ◽  
History Analysis ◽  
Nonlinear Time History

AbstractOne of the most important factors that make structures vulnerable to earthquakes is the short distance between structures and epicenter. Near-field earthquakes have special properties, such as increasing acceleration applied to the structure, which distinguishes them from far-field earthquakes. Therefore, the absorption of input energy for structures located near the faults is very important. Hence, by rotating the earthquake acceleration time history and comparing the resulting spectral acceleration response, the angle which applies the greatest force to the structure on the earthquake directivity side is obtained, and then the performance of a steel structure with viscoelastic dampers (VED) under near-field earthquakes with directivity feature is investigated. After analyzing the structure using nonlinear time history analysis, it was observed that the directivity phenomenon leads to significant increase in the force applied to the structure, but the viscoelastic dampers showed an acceptable performance in both states of with and without directivity.

scholarly journals Effect of a Near Fault on the Seismic Response of a Base-Isolated Structure with a Soft Storey

2017 ◽  
Vol 25 (4) ◽  
pp. 34-46
Author(s):  
B. Athamnia ◽  
A. Ounis ◽  
M. Abdeddaim
Keyword(s):  
Seismic Isolation ◽  
Seismic Analysis ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Base Shear ◽  
Rc Structures ◽  
Soft Storey ◽  
Near Fault ◽  
Nonlinear Time History ◽  
Far Fault

AbstractThis study focuses on the soft-storey behavior of RC structures with lead core rubber bearing (LRB) isolation systems under near and far-fault motions. Under near-fault ground motions, seismic isolation devices might perform poorly because of large isolator displacements caused by large velocity and displacement pulses associated with such strong motions. In this study, four different structural models have been designed to study the effect of soft-storey behavior under near-fault and far-fault motions. The seismic analysis for isolated reinforced concrete buildings is carried out using a nonlinear time history analysis method. Inter-story drifts, absolute acceleration, displacement, base shear forces, hysteretic loops and the distribution of plastic hinges are examined as a result of the analysis. These results show that the performance of a base isolated RC structure is more affected by increasing the height of a story under nearfault motion than under far-fault motion.

scholarly journals Research on Application of Buckling Restrained Braces in Strengthening of Concrete Frame Structures

2020 ◽  
Vol 6 (2) ◽  
pp. 344-362
Author(s):  
Niyonyungu Ferdinand ◽  
Zhao Jianchang ◽  
Yang Qiangqiang ◽  
Guobing Wang ◽  
Xu Junjie
Keyword(s):  
Bearing Capacity ◽  
Time History ◽  
Time History Analysis ◽  
Nonlinear Time History Analysis ◽  
Frame Structures ◽  
Concrete Frame ◽  
History Analysis ◽  
Seismic Design Code ◽  
Buckling Restrained Braces ◽  
Nonlinear Time History

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.

Time History Input Development for the Seismic Analysis of Piping Systems

1980 ◽  
Vol 102 (2) ◽  
pp. 212-218 ◽  
Author(s):  
C.-W. Lin
Keyword(s):  
Degrees Of Freedom ◽  
Seismic Analysis ◽  
Time History ◽  
Response Spectra ◽  
Nonlinear Time History Analysis ◽  
System Response ◽  
Ground Response ◽  
Piping Systems ◽  
Statistical Relationships ◽  
Nonlinear Time History

In a nonlinear time history analysis of piping systems, the system response is generally highly coupled for all dynamic degrees-of-freedom. Therefore, the seismic time history input components, which are usually synthesized from the Regulatory Guide 1.60 spectra, play an important role in the piping seismic analysis. The design ground response spectra recommended in Regulatory Guide 1.60 are identical for both horizontal directions. No specific requirements are given to define their statistical relationships. As a result, the two horizontal components could either be identical or with erroneous relationships which could adversely affect the analysis. In this paper, the results of a study conducted to establish statistical relationships on 22 earthquakes are reported. These earthquakes are those used in establishing the design ground response spectra specified in Regulatory Guide 1.60. The statistical properties studied include the autocorrelation functions, crosscorrelation functions, coherence functions, and acceleration motion distribution. A set of criteria is recommended for the generation of the synthesized time histories so that analysis of the piping systems can be realistically and correctly conducted.

Study on Corrugated Steel Web Bridge Seismic Isolation Technology in High Intensity Seismic Region

2014 ◽  
Vol 919-921 ◽  
pp. 965-968
Author(s):  
Hong Xue Li ◽  
Yong Ming Zhao
Keyword(s):  
Seismic Isolation ◽  
Rapid Development ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Seismic Action ◽  
Bridge Structure ◽  
Seismic Region ◽  
Composite Bridge ◽  
Corrugated Steel Web ◽  
Nonlinear Time History

The rapid development of modern seismic isolation technology has opened up new avenues of bridge seismic. For the bridge structure in highly seismic region,seismic isolation devices reduce the effects of the earthquake damage to bridges, but also reduce the ability of the bridge structure to resist other loads along with the increase of the displacement under seismic action. Nowadays, there are few engineering examples of the composite bridge with corrugated steel webs using seismic isolation technology. In this paper, we use Bridge Xiaoshagou as an example to study isolation technology with nonlinear time history analysis.

Dynamic Characteristics of Base-Isolated Steel Frame under Seismic Ground Motion

2011 ◽  
Vol 255-260 ◽  
pp. 2341-2344
Author(s):  
Mohammad Saeed Masoomi ◽  
Siti Aminah Osman ◽  
Ali Jahanshahi
Keyword(s):  
Ground Motion ◽  
Base Isolation ◽  
Time History ◽  
Steel Structure ◽  
Steel Structures ◽  
Steel Frame ◽  
Nonlinear Time History Analysis ◽  
Seismic Load ◽  
Vector Method ◽  
Seismic Ground Motion

This paper presents the performance of base-isolated steel structures under the seismic load. The main goals of this study are to evaluate the effectiveness of base isolation systems for steel structures against earthquake loads; to verify the modal analysis of steel frame compared with the hand calculation results; and development of a simulating method for base-isolated structure’s responses. Two models were considered in this study, one a steel structure with base-isolated and the other without base-isolated system. The nonlinear time-history analysis of both structures under El Centro 1940 seismic ground motion was used based on finite element method through SAP2000. The mentioned frames were analyzed by Eigenvalue method for linear analysis and Ritz-vector method for nonlinear analysis. Simulation results were presented as time-acceleration graphs for each story, period and frequency of both structures for the first three modes.

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