Isolated Structures Research and Comparative with Traditional Seismic Structures

2012 ◽  
Vol 594-597 ◽  
pp. 1734-1739
Author(s):  
Min Yao ◽  
Tie Ying Li

This paper introduces the concept and design method of the base isolation structure, through the SAP2000 software to analyze 6-story reinforced concrete frame for nonlinear time-history analysis, comparison of isolated and non-isolated structure's maximum displacement, acceleration under frequent earthquake and the maximum displacement, acceleration of isolation structure under rare earthquake. The results show that the isolated structure have a much better seismic responding than the traditional structures.

Author(s):  
Hye-min Shin ◽  
Kyung-jae Shin ◽  
Su-woong Lee ◽  
Dae-geun Kim ◽  
Min-ki Lee ◽  
...  

On November 15, 2017, the second strongest earthquake occurred in Korea, which was 5.4 in size on the Richter Scale. The duration of the earthquake was short, but the damage was serious. Two recent earthquakes have shown that our country is no longer safe from earthquakes. However, to date, Korean structures are showing a low earthquake resistance, and seismic retrofitting is necessary in preparation for a large-scale earthquake. In this study, reinforcing effect of steel slit damper was analyzed based on the dynamic test results of the previously studied reinforced concrete frame. After that, push over analysis and nonlinear time history analysis using OpenSees were selected for the residential piloti-type building as the target building. In the above Korean earthquake, the damage to the piloti-type building was conspicuous. Through analysis, the vulnerable part of the piloti-type building was identified and the seismic strengthening with the steel slit damper was carried out.


2014 ◽  
Vol 580-583 ◽  
pp. 1458-1462
Author(s):  
Min Sheng Guan ◽  
Hong Biao Du ◽  
Wei Chen ◽  
Yu Hua Wu

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.


2013 ◽  
Vol 671-674 ◽  
pp. 782-785
Author(s):  
Bin He ◽  
Jin Lai Pang ◽  
Cheng Qing Liu

For the lack of research in the longitudinal frame of prefabricated structure for its weak lateral stiffness, pushover analysis is conducted to evaluate the seismic performance of a fabricated concrete frame. Based on case study, the strengthening strategies with viscous dampers are analyzed. In view of the undesirable drift distribution and failure mode in the existing building, it is believed that arrangement of dampers should be designed to attain a uniform drift distribution. Based on the nonlinear time history analysis method, the strategy of damper allocation in vertical direction of the structure is investigated .Results indicate that a proper design might be attained based on the property of existing system, leading to a uniform drift distribution and better seismic performance.


2016 ◽  
Vol 20 (7) ◽  
pp. 1125-1138 ◽  
Author(s):  
Jing Yu ◽  
Xiaojun Liu ◽  
Xingwen Liang

A new model that can simulate the behavior of construction joint subjected to seismic forces was proposed. Nonlinear time-history analysis was carried out for reinforced concrete regular frame structures designed in different seismic intensity regions as well as with different height-to-width ratios. Two kinds of numerical models are adopted to simulate the seismic behavior of each frame, one with construction joint using the new proposed model and the other without construction joint using the conventional model. Results show that the influence of construction joint on the seismic behavior of reinforced concrete frame is strongly related to structural nonlinearity. It may increase the top displacement and the inter-story drift, change the inter-story drift distributions, and exacerbated the local reaction of key members. The influence of construction joint cannot be ignored for structures with low emergency capacity against major earthquake. Seismic design suggestions are proposed from the aspect of calculation analysis method.


2011 ◽  
Vol 243-249 ◽  
pp. 740-745 ◽  
Author(s):  
Qing Ning Li ◽  
Qing Mei Liu ◽  
Lin Zhao

A steel reinforced concrete frame-concrete core wall structure is taken as the research object in this paper. The whole space finite element models are established by software ETABS, modal analysis, response spectrum method and elastic time-history analysis are conducted. And static elastio-plastic time history analysis of the high-rise structure is conducted by software MIDAS/GEN. Seismic response of the high-rise structure is analyzed under medium earthquake and rare earthquake , elastic deformation is calculated under conventional earthquake and elastic-plastic deformation is calculated under rare earthquake. The results show that the structure can meet the requirements of no-damage under light earthquake, repairable under medium earthquake and no-collapse under strong earthquake.


2014 ◽  
Vol 578-579 ◽  
pp. 1361-1365
Author(s):  
Lin Liu ◽  
Xuan Min Li ◽  
Wei Tian

Friction Pendulum Systems have been used as base isolation systems for both new construction and retrofit around the world. This paper presented its implementation in an office building located in Shanghai. To evaluate its impact on seismic performance of the retrofitted structure, models are needed to capture the intricate nonlinear behavior of both structural components and isolator elements. Nonlinear time history analysis of the building for the original and retrofitted cases was conducted to assess the efficiency of the isolation system at the high earthquake level. The numerical results indicate that the retrofitted structure experiences significantly less damage and less deformation due to the shake isolation and energy dissipation through the isolators.


2021 ◽  
Vol 309 ◽  
pp. 01136
Author(s):  
Siripuram Vamshisheela ◽  
Atulkumar Manchalwar

In this work the performance of U-Shaped Steel Isolator is evaluated for a 5-story building subjected to seismic and blast vibrations. The structure is analysed using SAP 2000 software and a nonlinear time history analysis is carried out. The effectiveness of using base isolation is studied by comparing the structural responses of the building with isolator and without isolator and noticeable difference was observed. As the U-Shaped isolator absorbs the energy in all directions, it effectively controls the structural responses. In this study, the building is subjected to four different seismic and four different blast induced ground motions. It was observed that by the use of supplementary energy device there is reduction in top story acceleration, base shear and less deformation in the structure. This study concludes that the use of isolator has been effective in minimizing structural responses.


2015 ◽  
Vol 23 (18) ◽  
pp. 2926-2941 ◽  
Author(s):  
Ali Arzeytoon ◽  
Ali Akbar Golafshani ◽  
Vahab Toufigh ◽  
Hossein Mohammadi

In this article, a novel passive control system, ribbed bracing system (RBS), has been proposed to deal with the buckling problem. RBS is a bracing system with a simple mechanism that can be installed in braces as a supplemental part. The behavior of RBS is similar to that of conventional braces under tensile loading. However, under compressive force, it endures an insignificant force and prevents the braces from buckling through length reduction. In addition, seismic damage is concentrated in the bracing system of the structures equipped with RBS, decreasing the dissipated hysteretic energy in other structural members. There are two different mechanisms for RBS: 1) completely-closed RBS (CC-RBS) and 2) self-centering RBS (SC-RBS). The concept and mechanics of RBS have been verified by the results obtained from cyclic testing and numerical analysis of RBS specimens. In this research, after describing the mechanical configuration of RBS, nonlinear time history analysis has been conducted on 3-story and 6-story concentrically braced frames subjected to different seismic intensity levels, design basis earthquakes (DBE), and maximum considered earthquakes (MCE). The analyses have been performed on different types of bracing systems as follows: SC-RBS, CC-RBS, and Buckling Restrained Braces (BRB). The results show that SC-RBS frames have negligible residual story drifts, and maximum displacement in CC-RBS is slightly lower than that of BRB. Additionally, distribution of input energy into the structure was considered and showed that RBS frames demonstrate a high hysteretic energy dissipation, which results in lower demands in other structural elements.


2012 ◽  
Vol 204-208 ◽  
pp. 3592-3595
Author(s):  
Xiao Song ◽  
Peng Li ◽  
Guang Sheng Xu

Design process and the nonlinear time history analysis for base isolation system is performed in this paper. The results show that the earthquake acceleration and displacement response of isolated structure can be significantly reduced. Application of the isolation system to improve the seismic capacity of the structure,can effectively reduce the response of upper structure of in earthquake.


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