scholarly journals Comparison of Modelling Strategies of R.C Walls for Seismic Analysis

2021 ◽  
Vol 1197 (1) ◽  
pp. 012067
Author(s):  
Syed Hamim Jeelani ◽  
Salim Akhtar ◽  
N Lingeshwaran ◽  
Durga Chaitanya Kumar Jagarapu ◽  
M A Mohammed Aslam ◽  
...  
Keyword(s):  
Seismic Analysis ◽  
Response Spectrum ◽  
Time History ◽  
Shell Element ◽  
Point Of View ◽  
Element Discretization ◽  
Shell Elements ◽  
Design Engineers ◽  
Equivalent Strut ◽  
Modelling Strategies

Abstract Reinforced concrete walls are being widely adopted as lateral load resisting systems for high rise structures. The current practice among design engineers for modelling of such walls is by idealizing the same as ‘wide’ columns, which is uncertain from safety as well as economy point of view. The most efficient modelling strategy of RC walls involves use of shell elements. Such an approach can be computationally much intensive, especially from a seismic analysis perspective. The present study utilizes an equivalent strut approach for modelling RC walls. The modelling strategy is demonstrated on a G + 15 storey residential apartment located in Calicut city. The proposed methodology will be compared with the traditional ‘wide’ column method as well as the one with shell element discretization. Comparison of modal properties such as frequencies and vibration modes from the various models are initially made to assess the model accuracy. Various seismic analyses viz. Equivalent static approach, Response spectrum approach and the assessment the storey shear, inter storey drifts as well as computation times using various models were performed using time history analysis. From preliminary results, it is understood that the modelling strategy could serve as an efficient alternative to more robust and computationally demanding scheme involving use of shell elements.

scholarly journals Review on Seismic Analysis of Multistoried Building in Hilly Region

2021 ◽  
Vol 9 (12) ◽  
pp. 73-79
Author(s):  
Harsh Joshi
Keyword(s):  
Seismic Analysis ◽  
Response Spectrum ◽  
Center Of Mass ◽  
Time History ◽  
Lateral Loads ◽  
Base Shear ◽  
Building Frames ◽  
Building Frame ◽  
History Analysis ◽  
Hilly Region

Abstract: Due to sloping land and high seismically active zones, designing and construction of multistory buildings in hilly regions is always a challenge for structural engineers. This review paper focuses to establish a review study on the Possible Types of building frame configuration in the hilly region and he behavior of Such building frames under seismic loading conditions, and (3) The recent research and developments to make such frames less vulnerable to earthquakes. This paper concludes that the dynamics characteristics of such buildings are significantly different in both horizontal and vertical directions, resulting in the center of mass and center of stiffness having eccentricity at point of action and not vertically aligned for different floors. When such frames are subjected to lateral loads, due to eccentricity it generates torsion in the frame. Most of the studies agree that the buildings resting on slanting ground have higher displacement and base shear compared to buildings resting on plain ground and the shorter column attracts more forces and undergoes damage when subjected to earthquake. Keywords: Building frame configuration, Seismic behavior, Dynamic characteristics, Response spectrum analysis, time history analysis.

Evaluation of Seismic Integrity for an Integral Reactor Assembly

2004 ◽  
Author(s):  
Soon Myeon Wang ◽  
J. S. Kim ◽  
T. E. Jin ◽  
M. J. Jhung ◽  
Y. H. Choi ◽  
...  
Keyword(s):  
Modal Analysis ◽  
Seismic Analysis ◽  
Coupling Effect ◽  
Response Spectrum ◽  
Safety Margin ◽  
Time History ◽  
Element Model ◽  
Seismic Safety ◽  
Reactor Assembly ◽  
Integral Reactor

The structural integrity of integral reactor assembly of 65Mwt thermal capacity is assessed by using the commercial finite element package ANSYS in order to evaluate the seismic safety margin. First of all, the modal analyses are performed using the various analysis models with/without the fluid coupling effect in order to validate a super element model and to evaluate the coupling effect on natural frequency. Based on the modal analysis results, the seismic analyses are performed using the ground response spectrum defined in Reg. Guide 1.60. Finally, time-history analyses are performed using the modal analysis results, the super element model and an inertia load approach. As a result, the reliable and efficient seismic analysis model for an integral reactor assembly is developed and it is found that an integral reactor assembly has the sufficient seismic safety margin.

A Parametric Study of Independent Support Motion Method for the Steam Supply Piping Connected to the HP Turbine of APR 1400

2013 ◽  
Author(s):  
Dae Soo Kim ◽  
Joon Ho Lee ◽  
In Yeung Kim
Keyword(s):  
High Pressure ◽  
Power Plant ◽  
Support Groups ◽  
Seismic Analysis ◽  
Response Spectrum ◽  
Time History ◽  
Nuclear Industry ◽  
Combination Method ◽  
Piping System ◽  
Support Motion

The steam supply piping connected to the high pressure (HP) turbine of APR1400 (Korea’s advanced power plant 1400 MW-class) is a typical example of multi-supported piping system, and it is routed from the Containment building to the Turbine building via the Main Steam Isolation Valve House in the Auxiliary building. In the seismic analysis of this piping system, using the Enveloped Response Spectrum (ERS) method, a commonly used methodology for seismic analysis of nuclear power plant piping in industry circles, generates overly conservative analysis results. Therefore, Time History Method (THM) which applies excitation characteristic of each support attached to individual building was used to eliminate unnecessary conservatism. However, it was noticed that the Time History Method requires considerable amount of labor and time in generating combined time history equivalent to the spectrum applied for each support although it is regarded as the most exact and realistic method for seismic analysis. The nuclear industry has been making lots of efforts in finding out the mathematic logicality and practical applicability to resolve this issue. This paper deals with parametric research on combination effects of responses between support groups, damping effects, and modal combination method with close modes in applying the Independent Support Motion (ISM) method to the analysis model of the steam supply piping connected to the high pressure turbine of APR1400. Quantitative assessment and comparison with the analysis results of the ERS method and THM were also carried out. As a result, it is shown that the analysis results of the ISM method together with the SRSS combination between support groups, 4% damping with ±15% spectrum peak broadening and grouping of modal combination are remarkably similar to those of THM.

scholarly journals Dynamic Characteristics of submerged floating tunnel under irregular waves

2019 ◽  
pp. 121-129
Keyword(s):  
Dynamic Characteristics ◽  
Transfer Functions ◽  
Response Spectrum ◽  
Time History ◽  
Point Of View ◽  
Irregular Waves ◽  
Classical Solutions ◽  
3D Fem ◽  
Immersed Tunnel ◽  
Submerged Floating Tunnel

submerged floating tunnel (SFT) is an innovative structural solution for waterway crossings and is based on the idea of Archimedes Buoyancy. The main structure is kept at a certain depth underwater and is placed in position by anchor/mooring cables. SFT becomes a more economical alternative for waterways compared to classical solutions such as cable-supported bridge, immersed tunnel or underground tunnel when the width and depth of the waterway are large enough. As SFT is completely submerged in water and is subjected to extreme environmental conditions such as waves, earthquakes, and hurricanes, therefore, the evaluation the dynamic characteristics of an SFT under irregular waves is a key demand from the design point of view. In this study, the responses of an SFT that is to be built in Qindao Lake of China are investigated under irregular waves. A 3D FEM model for SFT was established, the tunnel was modeled by 3D beam elements and cables were modeled by elastic catenary elements. The irregular waves were modeled by JONSWAP spectrum. The time history analysis was performed under irregular waves and currents. The time-domain simulations were transformed to the frequency domain by Fast Fourier Transform (FFT). The spectra were smoothed using Savitzky-Golay smoothing filters. The transfer functions of SFT horizontal and vertical displacements; and cable tensions were obtained for 30 realizations. Two major peaks have been observed in each transfer function (response spectrum). One of the peaks was associated with the peak wave frequency; the second peak was associated with the translational natural frequency of the SFT.

Sensitivity of the Effective Seismic Support Damping in a Class I Piping System to Analysis Parameters

2009 ◽  
Author(s):  
Nima Zobeiry
Keyword(s):  
Seismic Analysis ◽  
Response Spectrum ◽  
Time History ◽  
Class I ◽  
Piping System ◽  
Frequency Content ◽  
Response Spectrum Analysis ◽  
History Analysis ◽  
The Coefficient Of Friction ◽  
Seismic Damping

It is understood that the level of seismic damping in a piping system is strongly influenced by the supports. Put differently, the supports contribute to an effective damping that can be considered in the seismic analysis of the piping system. This paper investigates the issue for the feeder pipes of a CANDU™ reactor. Feeders are numerous class I pipes in parallel, which are separated by frictional spacer elements. The results of a time history analysis, taking into account different damping mechanisms, are compared to those from a response spectrum analysis to deduce the effective damping in the system. The sensitivity of the effective damping to different parameters, such as the coefficient of friction and the input frequency content, is investigated.

scholarly journals Proposed Simplified Approach for the Seismic Analysis of Multi-Storey Moment Resisting Framed Buildings Incorporating Friction Sliders

Buildings ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 130 ◽  
Author(s):  
Shahab Ramhormozian ◽  
G. Charles Clifton ◽  
Massimo Latour ◽  
Gregory A. MacRae
Keyword(s):  
Seismic Analysis ◽  
Time History ◽  
Point Of View ◽  
Friction Damper ◽  
Simplified Approach ◽  
Analysis And Design ◽  
Residual Drift ◽  
Moment Resisting ◽  
Design Earthquake ◽  
Column Base

An innovative, simplified, and accurate model is proposed and developed to enable simplified yet realistic time history analysis of multi-storey buildings with moment resisting connections using friction energy dissipaters in the commonly used structural analysis and design program, SAP2000. The analyses are rapid to undertake, thereby enabling detailed study of the influence of many building system effects on the overall response. This paper presents the outcome of dynamic analysis of a complete 13-storey moment resisting steel building with Sliding Hinge Joints as the beam-column connections, considering the influential self-centring factors such as MRF and gravity columns continuity as well as column base and diaphragm flexibilities. The building is one of the Te-Puni towers, which are structural steel apartment buildings with steel-concrete composite floors, designed according to the low damage design philosophy, built in Wellington, New Zealand in 2008 and which have already been subjected to two significant earthquakes. The key objectives of the research have been to take the design of the 13-storey building and convert that into the proposed simplified model required for time history seismic analysis, to undertake analysis under scaled El-Centro earthquake record, investigate the peak inter-storey drift and the residual drift of the building, and determine the influence of column base rotational stiffness, floor slab out of horizontal plane displacement, type of friction damper, and MRF and gravity column continuity. It is concluded that the response of the building is stable and predictable, as expected, and that the post-earthquake state of the building, particularly from the self-centring point of view, is well within the limits for maintaining operational continuity following an ULS level design earthquake.

Seismic Analysis of Long Span Double-Curved Arch Bridge

2012 ◽  
Vol 594-597 ◽  
pp. 1532-1536
Author(s):  
Yun Zhang ◽  
Xiu Feng Huang ◽  
Bei Li
Keyword(s):  
Seismic Analysis ◽  
Response Spectrum ◽  
Time History ◽  
Element Model ◽  
Dynamic Features ◽  
Arch Bridge ◽  
Long Span ◽  
Crown Structure ◽  
History Analysis ◽  
Rare Earthquake

Take one long span double-curved arch bridge as the example, built the finite element model of bridge structure and analyzed the modeling method, dynamic features and response under ground motion. It demonstrates that response spectrum method could meet the calculation requirement in seismic analysis of the double-curved arch bridge, and the result accords with time-history analysis method. Bridge vibration type is dispersing in quality distribution of double-curved arch bridge; it should take adequate vibration types in bridge combination. At frequent earthquake, it is actual to considerate the coalition function between arch crown structure and the main arch ring. But at rare earthquake, the arch crown buildings of masonry structure is easy to be damaged, it is not suitable to considerate the coalition function in bridge reinforcement.

scholarly journals Application of Hilbert-Huang Transform in Generating Spectrum-Compatible Earthquake Time Histories

2011 ◽  
Vol 2011 ◽  
pp. 1-17 ◽  
Author(s):  
Shun-Hao Ni ◽  
Wei-Chau Xie ◽  
Mahesh Pandey
Keyword(s):  
Seismic Design ◽  
Seismic Analysis ◽  
Response Spectrum ◽  
Time History ◽  
Relative Difference ◽  
Hilbert Huang Transform ◽  
Analysis And Design ◽  
Design Spectra ◽  
Earthquake Records ◽  
Time Histories

Spectrum-compatible earthquake time histories have been widely used for seismic analysis and design. In this paper, a data processing method, Hilbert-Huang transform, is applied to generate earthquake time histories compatible with the target seismic design spectra based on multiple actual earthquake records. Each actual earthquake record is decomposed into several components of time-dependent amplitude and frequency by Hilbert-Huang transform. The spectrum-compatible earthquake time history is obtained by solving an optimization problem to minimize the relative difference between the response spectrum of the generated time history and the target seismic design spectra. Since the basis for generating spectrum-compatible earthquake time histories is derived from actual earthquake records by employing the Hilbert-Huang transform, the nonstationary characteristics and the natural properties of the seed earthquake records are well preserved in the generated earthquake time histories.

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