scholarly journals Isolating system using U Shaped steel damper

2021 ◽  
Vol 309 ◽  
pp. 01136
Author(s):  
Siripuram Vamshisheela ◽  
Atulkumar Manchalwar
Keyword(s):  
Base Isolation ◽  
Ground Motions ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Base Shear ◽  
Energy Device ◽  
History Analysis ◽  
Structural Responses ◽  
Nonlinear Time History ◽  
Story Building

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.

scholarly journals Response control of structures under Seismic and Blast induced ground motions

2021 ◽  
Vol 309 ◽  
pp. 01137
Author(s):  
Vamshisheela Siripuram ◽  
Atulkumar Manchalwar
Keyword(s):  
Base Isolation ◽  
Ground Motions ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Base Shear ◽  
Rubber Bearing ◽  
Lead Rubber Bearing ◽  
Fixed Base ◽  
Isolation Device ◽  
Nonlinear Time History

In the present paper an investigation is carried out to evaluate the efficiency of Base Isolation device in a building subjected to both seismic and blast induced ground motions. A 5-story building is modelled with different story stiffness and floor masses is considered in this study. In SAP 2000 software two buildings, one with fixed base and the other with isolated base are designed and nonlinear time history analysis is conducted. The structural responses of these two models subjected to four recorded earthquakes and four different blast ground accelerations is compared in this study. The base isolated device such as lead/rubber bearing have proved to be effective in reducing the base Shear and Top story acceleration, and also increase in Hysteresis energy in the base isolated structure subjected to seismic and blast vibrations.

HHT-BASED SIMULATION OF UNIFORM HAZARD GROUND MOTIONS

2009 ◽  
Vol 01 (01) ◽  
pp. 71-87 ◽  
Author(s):  
Y. K. WEN ◽  
PING GU
Keyword(s):  
Los Angeles ◽  
Ground Motions ◽  
Time History ◽  
Simulation Method ◽  
Nonlinear Time History Analysis ◽  
Rupture Directivity ◽  
Regional Seismicity ◽  
Hilbert Huang Transform ◽  
History Analysis ◽  
Nonlinear Time History

Hilbert–Huang Transform (HHT) is a new analysis method for nonstationary and nonlinear signals. A simulation method based on HHT is used to generate uniform hazard ground motions, which are often needed for nonlinear time history analysis for structures in high-seismic zones. The HHT-based simulation method can reproduce the amplitude and frequency content change with time for nonstationary random processes, thus is very suitable for the simulation of earthquake ground motions, especially the near-fault ground motions with long-period pulses. Monte-Carlo method and historical earthquake records are used for the generation of a large pool of ground motions, from which the uniform hazard ground motions are selected. The regional seismicity and rupture directivity are considered. An example is given of a site near Los Angeles City Hall. The advantages and difficulties of the proposed method are also discussed.

Seismic Isolation Design of Multistory Building

2012 ◽  
Vol 204-208 ◽  
pp. 3592-3595
Author(s):  
Xiao Song ◽  
Peng Li ◽  
Guang Sheng Xu
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Seismic Capacity ◽  
Isolation System ◽  
Multistory Building ◽  
History Analysis ◽  
Base Isolation System ◽  
Nonlinear Time History

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.

scholarly journals Comparison and analysis of seismic isolation, energy dissipation structure and traditional seismic structure

2021 ◽  
Vol 248 ◽  
pp. 01001
Author(s):  
Shu-jiang Jiang ◽  
Shun-zhong Yao ◽  
De-wen Liu
Keyword(s):  
Seismic Isolation ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Seismic Structure ◽  
Base Shear ◽  
Finite Element Software ◽  
History Analysis ◽  
Rare Earthquake ◽  
Nonlinear Time History ◽  
The Impact

This paper uses SAP2000 finite element software to perform nonlinear time history analysis of nine structural systems, and compares the period, total floor displacement, base shear force, vertex displacement, and top acceleration of the structure under the action of an 8-degree rare earthquake. The research results show that seismic isolation and damping technology can effectively reduce the impact of earthquakes on structures.

Sensitivity analysis of the influence of ground motion intensity levels on the seismic behavior of steel frames in assessment of the target displacement considering near-fault effects

2020 ◽  
Vol 47 (4) ◽  
pp. 470-486
Author(s):  
Alireza Esfahanian ◽  
Ali Akbar Aghakouchak
Keyword(s):  
Ground Motions ◽  
Steel Frames ◽  
Time History ◽  
Time History Analysis ◽  
Nonlinear Time History Analysis ◽  
Seismic Demands ◽  
Near Fault ◽  
History Analysis ◽  
Nonlinear Time History ◽  
Far Fault

Nonlinear time-history analysis conducted as part of a performance-based seismic design approach often require that the ground motion records are selected and then scaled to a specified level of seismic intensity. In such analyses, besides an adequate structural model, a set of acceleration time-series is needed as the most realistic representation of the seismic action. In this paper, the effects of scaling procedure on seismic demands of steel frames are investigated. To this, two special steel moment-resisting frames with considerable higher mode effects, and two sets of ground motions, including near-fault and far-fault motions are considered. Moreover, three scaling procedures are introduced for performing nonlinear dynamic time-history analysis of structures. Among different demands, lateral roof displacement and interstory drift are selected as seismic demands. The height-wise distribution of demands shows that the inelastic seismic demands of the near-fault pulse-like ground motions differ considerably from those of far-fault ones. These results show that the story drifts are mostly larger for far-fault motions in the upper story levels in comparison to near-fault records and in the lower floors, the reverse is true. Thus, the scaling procedures directly affect the results of seismic demands and choosing different methods would result in varying responses. Moreover, a low-cost and fairly effective procedure is proposed to estimate the target displacement demands of buildings from response-spectrum analyses, considering near-fault effects. The precision of this method is verified by nonlinear time-history analysis results, as the benchmark solution, and acceptable improvements have been achieved.

scholarly journals Optimal Location of Multiple Tuned Mass Dampers in Regular and Irregular Tall Steel Buildings Plan

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Mohsen Khazaei ◽  
Reza Vahdani ◽  
Ali Kheyroddin
Keyword(s):  
Passive Control ◽  
Time History ◽  
Optimal Location ◽  
Nonlinear Time History Analysis ◽  
Steel Buildings ◽  
Base Shear ◽  
Tuned Mass Dampers ◽  
History Analysis ◽  
Nonlinear Time History ◽  
Multiple Tuned Mass Dampers

Tuned mass dampers are one of the most common devices for the passive control of structures subjected to earthquakes. The structure of these dampers consists of three main parameters: mass, damping, and stiffness. Tuned mass dampers reduce the amplitude of the responses affecting on a mode. In most cases, only a single TMD (tuned mass damper) or a few dampers at several points above the building height are installed on the roof of the building, requiring considerable mass and space in some parts of the structure as overhead. It is also more important to predict the elements that will meet the required mass. In this research, the performance of multiple tuned mass dampers (MTMDs) is investigated in L- and U-shaped regular and irregular tall steel buildings with 10 and 20 floors, under the near- and far-field records. Nonlinear time history analysis is also applied to evaluate the multiple tuned mass dampers effects on the seismic responses of the structures. The SAP2000 API and MATLAB genetic algorithm are used to determine the optimal location of the MTMDs in the roof plans of the buildings. The results show the effects of multiple tuned mass dampers in reducing the seismic response of acceleration, displacement, and base shear up to 50, 40, and 40% in average, respectively. The results of determining the optimum location of MTMDs in the models indicate the importance of the symmetry of the dampers relative to the centre of mass of the building.

scholarly journals Response of Multi-Storeyed Buildings Having Vertical Irregularities using ETABS

2019 ◽  
Vol 8 (12) ◽  
pp. 536-540
Keyword(s):  
Time History ◽  
Nonlinear Time History Analysis ◽  
Centre Of Mass ◽  
Base Shear ◽  
Centre Of Gravity ◽  
History Analysis ◽  
Story Drift ◽  
Irregular Buildings ◽  
Nonlinear Time History ◽  
Structural Engineers

The objective of this research is to analyze the regular and vertical irregular buildings for understanding the response of vertically irregular buildings by using advanced software like ETABS. The analysis is carried out to understand the behaviour of the buildings by performing Non-Linear Dynamic analysis (Nonlinear Time-History Analysis) in software. The response of buildings is analyzed for three different irregularities, they are i) mass irregularity ii) stiffness irregularity iii) setback irregularity. The response of the vertically irregular buildings with regular building is done by considering the Base shear, Displacement and Story Drift of the buildings. The buildings which are irregular in plan will undergo to torsion effects easily because their centre of mass does not coincide with the centre of gravity, since the torsion will be developed in the building. When comes to the buildings which are irregular in elevation and located in seismic zones, the understanding of behaviour of such vertically irregular buildings will be difficult. It is a challenging task to the structural engineers to study the behaviour of vertically irregular buildings. This paper will provide the response of vertical irregular buildings so the engineers can design the buildings accordingly.

scholarly journals Performance of an Existing Reinforced Concrete Building Designed in Accordance to Older Indonesian Seismic Code: A Case Study for a Hotel in Kupang, Indonesia

2018 ◽  
Vol 20 (1) ◽  
pp. 35
Author(s):  
Pamuda Pudjisuryadi ◽  
Benjamin Lumantarna ◽  
Ryan Setiawan ◽  
Christian Handoko
Keyword(s):  
Plastic Hinge ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Seismic Load ◽  
Ground Acceleration ◽  
Seismic Code ◽  
Damage Level ◽  
History Analysis ◽  
Nonlinear Time History ◽  
Seismic Hazard Map

The recent seismic code SNI 1726-2012 is significantly different compared to the older code SNI 1726-2002. The seismic hazard map was significantly changed and the level of maximum considered earthquake was significantly increased. Therefore, buildings designed according to outdated code may not resist the higher demand required by newer code. In this study, seismic performance of Hotel X in Kupang, Indonesia which was designed based on SNI-1726-2002 is investigated. The structure was analyzed using Nonlinear Time History Analysis. The seismic load used was a spectrum consistent ground acceleration generated from El-Centro 18 May 1940 North-South component in accordance to SNI 1726-2012. The results show that Hotel X can resist maximum considered earthquake required by SNI 1726-2012. The maximum drift ratio is 0.81% which is lower than the limit set by FEMA 356-2000 (2%). Plastic hinge damage level is also lower than the allowance in ACMC 2001.

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