scholarly journals Numerical Study on Seismic Response of Steel Storage Racks with Roller Type Isolator

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 158
Author(s):  
Oscar Álvarez ◽  
Nelson Maureira ◽  
Eduardo Nuñez ◽  
Frank Sanhueza ◽  
Ángel Roco-Videla
Keyword(s):  
Base Isolation ◽  
Numerical Study ◽  
Response Spectrum ◽  
Soft Soil ◽  
Flexible Structures ◽  
Time History ◽  
Seismic Zone ◽  
Low Frequencies ◽  
Isolation Device ◽  
Storage Racks

This research evaluates the effectiveness of using a roller-type base isolation device with tensile strength in reducing the dynamic response of industrial steel storage racks. These were subjected to a seismic input acting separately in both directions of the structure. The seismic record obtained from the earthquake that occurred in Llolleo, Chile, on 3 March 1985, was used as input. This earthquake was scaled in the frequency domain, adjusting its response spectrum to coincide with the design spectrum required by NCh2745. In the calculations of this spectrum, the most hazardous seismic zone (zone 3) and soft soil (soil III) that amplifies the effect of the low frequencies of the earthquake were considered. These frequencies are the ones that have the most affect on flexible structures such as high racks and systems with base isolation. Numerical time-history analyses were performed in fixed base racks and base isolation racks. In both cases, the models include semi-rigid connections with capacity for plastic deformation and energy dissipation. Parametric analyses were carried out considering the most relevant variables, using an algorithm programmed in MATLAB software. The maximum relative displacement, maximum basal shear load, and maximum absolute floor acceleration were considered as responses of interest. The results showed the effectiveness of using the base isolation device by reducing the absolute accelerations between approximately 75% and 90%, compared to the same fixed rack at its base. This makes it possible to reduce the vulnerability of the stored load to overturn under the action of a severe earthquake.

scholarly journals The effect of seismic base isolation on structural response of a 12-story hotel building in Padang, Indonesia

2020 ◽  
Vol 156 ◽  
pp. 05026
Author(s):  
Fauzan ◽  
Afdhalul Ihsan ◽  
Mutia Putri Monika ◽  
Zev Al Jauhari
Keyword(s):  
Base Isolation ◽  
Response Spectrum ◽  
Soft Soil ◽  
Structural Response ◽  
Time History ◽  
Seismic Zone ◽  
Isolation System ◽  
Rubber Bearing ◽  
Seismic Base Isolation ◽  
The City

The amount of potential investment in Padang City, Indonesia since 2017 attracted many investors to contribute to the city. One of the investments is a 12-story hotel that will be constructed in By Pass Street of the city. The hotel is located in a high seismic zone area, so the seismic base isolation has been proposed to be used in the hotel building. The main aim of using a seismic base isolation device is to reduce the inertia forces introduced in the structure due to earthquakes by shifting the fundamental period of the structure out of dangerous resonance range and concentration of the deformation demand at the isolation system. An analytical study on the Reinforced Concrete (RC) hotel building with and without rubber bearing (RB) base isolation is carried out using the response spectrum and time history analysis methods. The results show that internal forces and inter-story drift of the building with high damping rubber bearing (HDRB) are lower than that of the fixed base with a remarkable margin. From this study, it is recommended to use the HDRB base isolation for medium and high rise buildings with soft soil in Padang City, Indonesia.

scholarly journals Response Spectrum Analysis of Base Isolated Regular and Vertical Irregular Building in Different Types of Soil

2021 ◽  
Vol 9 (10) ◽  
pp. 1095-1103
Author(s):  
Priya Namdev
Keyword(s):  
Spectrum Analysis ◽  
Passive Control ◽  
Base Isolation ◽  
Response Spectrum ◽  
Soft Soil ◽  
Type I ◽  
Seismic Zone ◽  
Type Ii ◽  
Response Spectrum Analysis ◽  
Fixed Base

Abstract: These days earthquake is a major problem for development of high rise building in seismic zone areas. Researchers have developed devices to overcome these earthquake problems. So we need to design a structure which can withstand against the seismic loads. There for it became necessity to provide passive control device “base isolation” to resists large horizontal and vertical loads which lead the structure to collapse. In present workthe effectiveness of the fixed base and Base isolation (LRB) with different type of vertical irregularities in different type of soil (Hard, Medium, Soft soil) in plan are concerned the vibration of the structure. The present work G+10 story Building of different vertical irregularities ( Regular building, vertical irregular Type-I, vertical irregular Type-II, vertical irregular Type-III ) Situated in zone IV are analyzed under the various Loading such as dead load, live load and earthquake load. Free vibration analysis, response spectrum analysis have been carried out for these model of building with a fixed base and base Isolation Devices. It is observed that story displacement in response spectrum is significantly increases at top stories with the base isolated building. And this work shows that the response of building reduced by using base isolation (LRB) devices in all different typeof vertical irregularities building, but the same isolation device is more effectively work in Vertical irregular Type-II Building Keywords: Base isolation Techniques, LRB, Base Shear and Etabs etc.

scholarly journals Seismic and Time History Performance of RCC Framed Buildings with and without Passive Energy Dissipators

2020 ◽  
Vol 9 (3) ◽  
pp. 2230-2240
Keyword(s):  
Base Isolation ◽  
Lateral Displacement ◽  
Response Spectrum ◽  
Time History ◽  
Base Shear ◽  
Viscous Dampers ◽  
Fluid Viscous Dampers ◽  
Seismic Force ◽  
Energy Dissipators ◽  
Lateral Displacements

Base isolation is an effective way to protect large structures from earthquake damage. It is a costly approach, as the entire structure must be supported on elastomeric or sliding bearings. Viscous dampers distributed throughout an otherwise conventional structure can achieve the same result at a significantly lower cost. Dampers are used to resist lateral forces coming on the structure. Dampers are the energy dissipating devices which also resist displacement of Reinforced Concrete (RC) buildings during an earthquake. These dampers help the structure to reduce buckling of columns thereby increasing the stiffness of the structure. During earthquakes, multi-storeyed buildings get damaged and as a result, large deformation occurs. Dampers reduce vibration and deformation of structural elements during an earthquake. Retrofitting buildings with fluid viscous dampers (FVDs) can improve Interstorey drifts and floor accelerations. In the present study, an RC framed building is modelled and analysed under Southern Sumatra and Chile earthquakes to evaluate the performance of the structure and its elements with and without energy dissipators. For the study, a model (G+19) with and without energy dissipators is modelled in ETABS. The seismic force is applied based on the time history data of the models pertaining to Southern Sumatra and Chile Earthquake. Response Spectrum analysis has been carried out to find the lateral displacements, storey shear and Base shear for the model with and without dampers. The lateral displacement, storey drift, storey shear and Base shear are found to less for the model with Linear FVDs when compared to the model with Non-Linear FVDs and without FVDs.

Numerical investigation on dynamic response of a steel lattice tower under various seismic events

2019 ◽  
Author(s):  
Tomasz Falborsk ◽  
Natalia Lasowicz
Keyword(s):  
Dynamic Response ◽  
Soil Structure ◽  
Numerical Study ◽  
Soft Soil ◽  
Time History ◽  
Time History Analysis ◽  
Modal Parameters ◽  
History Analysis ◽  
Lattice Tower ◽  
Ground Motion Records

The present paper presents the results of the numerical study designed to investigate the soil-structure flexibility effects on modal parameters (i.e. fundamental frequencies) and time-history analysis response (represented by the top relative displacements) of a 46.8 m high steel lattice tower subjected to a number of ground motions including also one mining tremor. In addition to the fixed-base condition, three different soil types (i.e. dense soil, stiff soil, and soft soil) were considered in this investigation. Site conditions were characterized by their average effective profile velocities, Poisson’s ratios, and finally mass densities. Soil-foundation flexibility was introduced using the spring-based approach, utilizing foundation springs and dashpots. The first step was to investigate the influence of different base conditions on modal parameters of the steel lattice tower. In the final part of the current study time-history analysis was performed using different two-component ground motion records (in two horizontal, mutually perpendicular directions). The results obtained indicate that modal parameters and dynamic response of the structure may be considerably affected by the soil-structure interaction effects. Therefore, the present paper confirms the necessity of utilizing soil-flexibility into numerical research.

Comparison between fixed base and isolated base in seismic response of high-rise buildings: a case study

2020 ◽  
Vol 6 (4) ◽  
pp. 204
Author(s):  
Anas M. Fares
Keyword(s):  
Response Spectrum ◽  
Soft Soil ◽  
Structural Response ◽  
Time History ◽  
Soil Condition ◽  
Soil Conditions ◽  
Spectral Acceleration ◽  
Base Shear ◽  
High Rise ◽  
Fixed Base

In this study, the influence of soil condition under the isolated and fixed bases is studied by using ETABS 16 software for the high-rise regular building. A regular building with 10 floors is modeled and the results are obtained for story displacements, story shear forces and spectral acceleration according to Uniform Building Code 97 (UBC-97) code. The time history analysis has been performed by using 1999 Izmit earthquake record. 3 types of soil which had different stiffnesses are considered in this study. The results show that the value of base shear increases when the soil stiffness decreases. It also noticed that the spectral acceleration is larger in soft soil condition than that of other soil conditions; and this confirms that the structural response spectrum is associated with the soil condition. In addition, when using base isolated building the drift of lower floors will be larger than that of using base isolated, but in the upper floors the drifts of fixed base building will be larger than that of the isolated base building. Finally, time history method in the seismic design will produce base shear less than that from equivalent static method, so calibration factor for design purpose shall be used.

Numerical Study on Dam-Foundation-Dam Interaction

2013 ◽  
Vol 353-356 ◽  
pp. 933-936
Author(s):  
Hong Zhong ◽  
Hong Jun Li
Keyword(s):  
Maximum Stress ◽  
Numerical Study ◽  
Response Spectrum ◽  
Time History ◽  
Artificial Boundary ◽  
Dam Foundation ◽  
Design Life ◽  
History Analysis ◽  
Two Systems ◽  
History Of

As dams approach the end of their design life periods, retrofitting of dams is needed in many cases. For the retrofitting procedure of building a new dam close to the existing old dam without demolishing it, the interaction between the two dams and the unbounded foundation is an important issue to be investigated. The influence of the existing dam on the dynamic response of the newly built dam is examined. Two systems are analyzed, i.e., the new dam-foundation system and the dam-foundation-dam system. For the two systems, modal analysis and time history analysis using the viscous-spring artificial boundary are performed. It’s found that there’re much more vibration frequencies for the dam-foundation-dam system as compared to the new dam-foundation system within the same frequency range. The existence of the old dam also induces one more peak and a wider plateau in the response spectrum of the acceleration time history of the dam crest. However, the maximum stress distribution is not influenced much by the old dam.

Numerical implementation of variable friction sliding base isolators and preliminary experimental results

2020 ◽  
Vol 36 (2) ◽  
pp. 767-787
Author(s):  
Tianye Yang ◽  
Paolo M Calvi ◽  
Richard Wiebe
Keyword(s):  
Base Isolation ◽  
Numerical Study ◽  
Three Dimensional ◽  
Structural Response ◽  
Time History ◽  
Experimental Results ◽  
Vertical Coupling ◽  
Moment Resisting ◽  
Variable Friction ◽  
Nonlinear Time History

The development of variable friction base isolation systems (VFSs) is the object of an ongoing international research project that involves extensive numerical and experimental activities. This article presents some of the recent numerical developments carried out as part of this project. More specifically, a three-dimensional (3D) variable friction (VF) element is formulated and implemented into OpenSees, providing the foundation for studying structural response in the context of nonlinear time history (NLTH) analysis. The element implementation captures the bearing bidirectional horizontal response along with horizontal–vertical coupling effects. Response predictions obtained using this newly implemented element are compared with the experimental results obtained from testing a full-scale VFS prototype, showing promising results. Finally, a demonstrative numerical study is carried out in which a steel moment resisting frame (MRF) structure, isolated using VFSs, is analyzed via NLTH analyses.

The Two-Stage Design Method of Isolated Structures Based on New Code for Seismic Design of Buildings

2013 ◽  
Vol 275-277 ◽  
pp. 1243-1249
Author(s):  
Qiang Qiang Zhang ◽  
Wen Pan ◽  
Bai Feng Sun
Keyword(s):  
Base Isolation ◽  
Design Method ◽  
Time History ◽  
Time History Analysis ◽  
Design Stage ◽  
Two Stage ◽  
Stage Design ◽  
Seismic Code ◽  
History Analysis ◽  
Isolation Device

Two-stage design method for base isolation structures includes simplified estimation and time history analysis. Simplified estimation is used in preliminary design stage for estimating the weight and the first period of an isolated structure, the upper structure is simplified as a SDOF system. According to the expected response reduction goals and response spectrum, the first period of the isolated structure, stiffness of isolation device and number of isolation bearing can be induced. Time history analysis is employed in detail design stage, for determination and optimization of isolation device based on current standards. The author has made it realized based on the old Seismic Code. As there are some changes of provision on base isolation analysis in new code, including the value of bearing stiffness and safety factor, etc., the method mentioned above should be updated. Numerical investigation shows that for regular multi-storey frame structures, the difference of the maxium ratio of floor shear between the old and new Seismic Code increase with fortification intensity.

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.

scholarly journals Analysis and Design of Stadium with Truss System and Shell Roof Subjected to Wind and Seismic Loading

2021 ◽  
Vol 10 (3) ◽  
pp. 55-66
Author(s):  
R Ashutosh V Kulkarni ◽  
◽  
Dr Aravindkumar B Harwalkar ◽  
Keyword(s):  
Reinforced Concrete ◽  
Response Spectrum ◽  
Time History ◽  
Paper Analysis ◽  
Seismic Zone ◽  
Analysis And Design ◽  
Bearing Plate ◽  
Moment Resisting ◽  
Plate Connection ◽  
Football Stadium

In this paper Analysis and Design of different Structural elements of the football stadium are presented, with particular emphasis on the Combination of Steel Truss without and with Shell roof cover and its interȧction with the underlying reinforced concrete structures. The Football stadium considered for the study is of rectangular plan, with 85 m width and 140 m length and height of 19.5 m. The plan of Football Stadium is generated in AutoCAD 2016 software. The Stadium structure is composed of special moment – resisting framed. Wind velocity is taken as 39 mph and Seismic zone IV in this study. The proposed stadium is analysed using Equivȧlent static and dynamic ȧpproach by Reṣponse ṣpectrum ȧnd Time Hiṣtory ȧnȧlysis. In anȧlysing the ṣtructure, 21 load combinations are used. The grandstand ṣtructure is made of reinforced concrete and the roof is of ṣtructural steel using Pipe and Tube sections. Deȧd loȧdṣ, live loȧdṣ, wind ȧnd ṣeismic loȧdingṣ data are considered bȧsed on IS-875 (PART 1-3) 1987 ȧnd IS:1893 (Part 1):2016. IS456:2000 and SP16:1987 code is used for Design of R.C.C components such as Beȧm, Column, Seating Platform, Footing and IS 800:2007 code is used for Design of End Beȧring Plate connection with Truss member. Analysiṣ of truss and other elements is carried out with software program of Staad. Pro V8i SS6 and also the designs are carried out as per provisions of relevant Indian standards. On introduction of Shell-like roof for Open Stadium which is used not only to protect the Game from Glare of Sunshine and Rain but also appears unique and attractive. From the obtained results it is observed that the displacement due to Wind action in both X and Z direction reduces significantly by the introduction of Shell roof. Also, due to RSA and THA there is reduction in the displacement on introduction of Shell-like roof to an Open Stadium.

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