Time History Broadening

2011 ◽  
Author(s):  
Andrzej T. Strzelczyk
Keyword(s):  
Time History ◽  
Support Point ◽  
Frequency Variation ◽  
Simple Modification ◽  
A Value ◽  
History Analysis ◽  
Point Motion ◽  
Asme Code ◽  
Time Histories ◽  
Frequency Variations

Section 6.5.2 of N283.3-10 of the CSA Standard [1] describes analytical methods for seismic qualification of nuclear components. Clause 6.5.2.2 of this Section instructs how to prepare seismic input for the time history method, specifically it states: “Time-histories of support point motion (displacement, velocity, or acceleration) may be used as dynamic inputs to components. To take into account the effects of possible frequency variations of component and structure, the analysis shall be carried out using three different time-history excitations. These time-histories shall be obtained by varying time scale of the original support point time-history by (a) 1.0; (b) 1 - Δfj/fj; and (c) 1 + Δfj/fj, where fj = the dominant structural frequency; Δfj = a parameter defining the frequency variation due to uncertainties in structural soil properties. The most severe effects obtained from these three time history analyses shall be considered in the design of the components. Notes: (1) A value of 15% for Δfj/fj may be used for the time-history analysis specified in this Clause; (2) For structures directly on bedrock, a value of Δfj/fj = 0% may be used”. This paper identifies some ambiguities in the approach described above. It shows, by theory and examples, that significantly different responses are obtained depending on which form of excitation is used (acceleration, velocity or displacement). In a typical acceleration excitation approach, the response may be over or under estimated. To remove this ambiguity, the paper proposes a simple modification of the broadening procedure described in [1]. The problem discussed in this paper may also be meaningful for the broadening time history described in Appendix N of ASME Code [2].

GENERATION OF A PAIR OF SURFACE TIME HISTORIES FOR JAKARTA USED FOR EARTHQUAKE RESISTANCE DESIGN OF INFRASTRUCTURES

2015 ◽  
Vol 77 (11) ◽  
Author(s):  
B.M. Hutapea ◽  
M. Asrurifak ◽  
Hendriyawan Hendriyawan ◽  
Masyhur Irsyam
Keyword(s):  
Ground Surface ◽  
Time History ◽  
Hazard Maps ◽  
Surface Time ◽  
History Analysis ◽  
Earthquake Design ◽  
Time Histories ◽  
Design Loads ◽  
Dynamic Time ◽  
The Impact

It is not the earthquake but the collapse of the building and infrastructure that will cause the damage and the loss of human lives. To mitigate these hazards, the building and infrastructure need to be designed such that will not collapse due to earthquake. This paper presents the procedure for generating time histories at ground surface for Jakarta area. Required data to generate these modified time histories were extracted from the Team for Revision of Seismic Hazard Maps of Indonesia 2010. The results are used as input motions in dynamic time history analysis for predicting earthquake design loads for infrastructures, such as bridges such that those structures can be designed to bear the impact of an earthquake and prevent collapse

Method for Selecting Stress States for Use in an NB-3200 Fatigue Analysis

2010 ◽  
Author(s):  
Thomas L. Meikle V ◽  
E. Lyles Cranford ◽  
Mark A. Gray
Keyword(s):  
Time History ◽  
Stress Range ◽  
Total Stress ◽  
Secondary Stress ◽  
Transient Stress ◽  
Automated Method ◽  
Relative Minimum ◽  
Asme Code ◽  
Time Histories ◽  
Stress States

In ASME Code Section III NB-3222.4 fatigue evaluations, selecting stress states to determine the stress cycles according to Section NB-3216.2, Varying Principal Stress Direction, can become a challenging and complex task if the transient stress conditions are the result of multiple independent time varying stressors. This paper will describe an automated method that identifies the relative minimum and maximum stress states in a component’s transient stress time history and fulfills the criteria of NB-3216.2 and NB-3222.4. Utilization of the method described ensures that all meaningful stress states are identified in each transient’s stress time history. The method is very effective in identifying the maximum total stress range that can occur between any real or postulated transient stress time histories. In addition, the method ensures that the maximum primary plus secondary stress range is also identified, even if it is out of phase with the total stress maxima and minima. The method includes a process to determine if a primary plus secondary stress relative minimum or maximum should be considered in addition to those stress states identified in the total stress time history. The method is suitable for use in design analysis applications as well as in on-line stress and fatigue monitoring.

Analysis of the Seismic Response of Long-Span Tube Shell Structures under Multi-Support Excitations

2012 ◽  
Vol 446-449 ◽  
pp. 751-755 ◽  
Author(s):  
Meng Hong Wang ◽  
Fei Da Song ◽  
Peng Zhuang ◽  
Song Song Shi
Keyword(s):  
Shell Structure ◽  
Time History ◽  
Peak Displacement ◽  
Finite Element Software ◽  
Long Span ◽  
History Analysis ◽  
Time Histories ◽  
Internal Forces ◽  
The Impact ◽  
Tube Shell

Analysis earthquake response of the long-span tube shell structure under multi-support excitations. The response of the long-span structure in the earthquake is different between multi-support excitations and uniform excitation. Using sap2000 finite element software with time history analysis, this paper analyzes the impact of the different visual velocities combining with the engineering Projects, and its internal forces and displacements. The results show the impact of the long-span tube shell structure under multi-support excitations. Draw structure peaking acceleration and displacement of time-histories. Result shows that: The appearances of structure under multi-support excitations and under uniform excitation have the same trend. The peak of acceleration and displacement of the structural is different from multi-support excitations and uniform excitation, and the time of occurrence of the peak acceleration and peak displacement is also different.

scholarly journals Seismic Design of Steel Structures with Special Flexural Frame Based on Performance by Durability Method

2018 ◽  
Vol 4 (12) ◽  
pp. 2926
Author(s):  
Pouyan Ashrafzadeh ◽  
Arash Kheyrolahi
Keyword(s):  
Seismic Analysis ◽  
Response Spectrum ◽  
Structural Response ◽  
Time History ◽  
Steel Structures ◽  
Finite Element Software ◽  
Durability Analysis ◽  
History Analysis ◽  
Time Histories ◽  
Minimum Number

Equivalent static, response spectrum and time history analysis are the well-known analysis methods that traditionally proposed. These methods are highly accurate but requires a great deal of time to match accelerations and the number of analyses, in the other words these methods are time consuming methods. Hence recently the structures are investigated using the durability time method, which plays an essential role in reducing the number of analyses that needs to be created; In fact, the durability time method is a new method of seismic analysis that is presented with a minimum number of time histories analysis. In this method the structure is placed under the influence of an increasing dynamic stimulation, structural response has been investigated over time and evaluated according to the corresponding response to different levels of stimulation intensity, strengths and weaknesses, and structural performance. In this study, steel folding frameworks with 5, 10 and 15 floors were investigated under two analytical methods (Time durability and Time histories methods). At first, the frameworks will be exposed under history of Imperial Governor, Kobe and Lumaprita earthquakes and analysis by finite element software ABAQUS. Then, based on the three analytical functions, the durability is investigated and the results are compared with each other. Finally, the behavior of the structures discussion and conclusion. The results show that the durability analysis method for earthquakes with higher intensity and time is more efficient, and for the Time-less earthquakes by time history method parametrically have a parametrical difference of 5%.

Generating Drift‐Free, Consistent, and Perfectly Spectrum‐Compatible Time Histories

2019 ◽  
Vol 109 (5) ◽  
pp. 1674-1690
Author(s):  
Lanlan Yang ◽  
Wei‐Chau Xie ◽  
Weiya Xu ◽  
Binh‐Le Ly
Keyword(s):  
Seismic Analysis ◽  
Time History ◽  
Accurate Method ◽  
Frequency Component ◽  
Engineering Structures ◽  
Influence Matrix ◽  
Analysis And Design ◽  
History Analysis ◽  
Time Histories ◽  
Eigenfunction Method

Abstract The focus of this article is on generating spectrum‐compatible acceleration, velocity, and displacement time histories for seismic analysis and design of engineering structures. If a generated acceleration time history is integrated to obtain the corresponding velocity and displacement time histories, it has been found that there are usually drifts in the resulting processes. Such drifts are due to overdeterminacy in the constants of integration. Baseline correction, although widely used, is not a suitable remedial measure to remove drift because it distorts the frequency content and renders the corrected processes no longer mutually consistent. The objective of this article is to develop an efficient and accurate method for generating drift‐free, consistent, and spectrum‐compatible time histories, which are essential properties for these time histories to be used as seismic input in time history analysis. To ensure drift‐free and consistent behavior, the eigenfunction method is applied to expand the time histories in eigenfunctions of a sixth‐order ordinary differential eigenvalue problem. The influence matrix method considering the influence of one frequency component on all others is capable of achieving perfect spectrum compatibility which has never been accomplished.

scholarly journals Simulation of Nonstationary and Nonhomogeneous Wind Velocity Field by Using Frequency–Wavenumber Spectrum

2021 ◽  
Vol 7 ◽  
Author(s):  
P. Hong ◽  
H. P. Hong
Keyword(s):  
Velocity Field ◽  
Wind Velocity ◽  
Time History ◽  
Computation Time ◽  
Wind Fields ◽  
Spectral Representation Method ◽  
Power Spectral ◽  
History Analysis ◽  
Time Histories ◽  
Representation Method

The time history analysis is used to estimate the peak responses of structures subjected to stationary and nonstationary winds. The time histories of the fluctuating wind processes at multiple points can be simulated based on the spectral representation method for given target auto and cross power spectral density (PSD) functions. As the number of the processes of interest increases, the computation time for the simulation increases drastically. For the stationary homogeneous or nonhomogeneous wind fields, this problem can be overcome by using the frequency-wavenumber PSD function to simulate the stochastic propagating waves or fields. In the present study, a technique to simulate the amplitude modulated and frequency modulated nonstationary and nonhomogeneous stochastic propagating wind fields is presented. The technique relies on representing the nonstationary wind velocity by amplitude modulating a process that is time transformed from a stationary process. It is based on the established relations between the PSD functions of the nonstationary and of the stationary wind velocity. Simple to use and implement equations to carry out the simulation for one-dimensional line wind velocity field and two-dimensional nonstationary and nonhomogeneous wind velocity field are presented. The use of the developed technique and its adequacy is illustrated through numerical examples.

PERILAKU STRUKTUR BAJA TIPE MRF DENGAN BEBAN LATERAL BERDASARKAN SNI 1726-2012 DAN METODE PERFORMANCE BASED PLASTIC DESIGN (PBPD)

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Nidiasari Jati Sunaryati Eem Ikhsan
Keyword(s):  
Pushover Analysis ◽  
Time History ◽  
Time History Analysis ◽  
Plastic Design ◽  
History Analysis ◽  
Non Linear ◽  
Static Pushover Analysis

Struktur rangka baja pemikul momen merupakan jenis struktur baja tahan gempa yang populer digunakan. Daktilitas struktur yang tinggi merupakan salah satu keunggulan struktur ini, sehingga mampu menahan deformasi inelastik yang besar. Dalam desain, penggunaan metode desain elastis berupa evaluasi non-linear static (Pushover analysis) maupun evaluasi non-linear analisis (Time History Analysis) masih digunakan sebagai dasar perencanaan meskipun perilaku struktur sebenarnya saat kondisi inelastik tidak dapat digambarkan dengan baik. Metode Performance-Based Plastic Design (PBPD) berkembang untuk melihat perilaku struktur sebenarnya dengan cara menetapkan terlebih dahulu simpangan dan mekanisme leleh struktur sehingga gaya geser dasar yang digunakan adalah sama dengan usaha yang dibutuhkan untuk mendorong struktur hingga tercapai simpangan yang telah direncanakan. Studi dilakukan terhadap struktur baja 5 lantai yang diberi beban gempa berdasarkan SNI 1726, 2012 dan berdasarkan metode PBPD. Hasil analisa menunjukkan bahwa struktur yang diberi gaya gempa berdasarkan metode PBPD mencapai simpangan maksimum sesuai simpangan rencana dan kinerja struktur yang dihasilkan lebih baik .

Response Law and Influencing Factors of the Soil under Action of Pile Driving Vibration Based on Midas/GTS

2013 ◽  
Vol 353-356 ◽  
pp. 979-983
Author(s):  
Dong Zhang ◽  
Jing Bo Su ◽  
Hui De Zhao ◽  
Hai Yan Wang
Keyword(s):  
Damping Ratio ◽  
Large Diameter ◽  
Time History ◽  
Pile Driving ◽  
Analysis Model ◽  
Vibration Load ◽  
History Analysis ◽  
Study Results ◽  
Propagation Law ◽  
Dynamic Time

Due to the upgrade and reconstruct of a high-piled wharf, the piling construction may cause the damage of the large diameter underground pipe of a power plant nearby. For this problem, a dynamic time-history analysis model was established using MIDAS/GTS program. Based on the analysis of the pile driving vibration and its propagation law, some parameters, such as the modulus of the soil, the Poissons ratio of soil, the action time of vibration load and the damping ratio of the soil that may have an effect on the response law of the soil, were studied. The study results not only serve as an important inference to the construction of this case, but also accumulate experience and data for other similar engineering practices.

scholarly journals Record-to-record variability and code-compatible seismic safety-checking with limited number of records

2021 ◽  
Author(s):  
Fatemeh Jalayer ◽  
Hossein Ebrahimian ◽  
Andrea Miano
Keyword(s):  
Seismic Hazard ◽  
Linear Time ◽  
Time History ◽  
Time History Analysis ◽  
Seismic Safety ◽  
Hazard Curve ◽  
History Analysis ◽  
Non Linear ◽  
Seismic Hazard Curve ◽  
Cloud Analysis

AbstractThe Italian code requires spectrum compatibility with mean spectrum for a suite of accelerograms selected for time-history analysis. Although these requirements define minimum acceptability criteria, it is likely that code-based non-linear dynamic analysis is going to be done based on limited number of records. Performance-based safety-checking provides formal basis for addressing the record-to-record variability and the epistemic uncertainties due to limited number of records and in the estimation of the seismic hazard curve. “Cloud Analysis” is a non-linear time-history analysis procedure that employs the structural response to un-scaled ground motion records and can be directly implemented in performance-based safety-checking. This paper interprets the code-based provisions in a performance-based key and applies further restrictions to spectrum-compatible record selection aiming to implement Cloud Analysis. It is shown that, by multiplying a closed-form coefficient, code-based safety ratio could be transformed into simplified performance-based safety ratio. It is shown that, as a proof of concept, if the partial safety factors in the code are set to unity, this coefficient is going to be on average slightly larger than unity. The paper provides the basis for propagating the epistemic uncertainties due to limited sample size and in the seismic hazard curve to the performance-based safety ratio both in a rigorous and simplified manner. If epistemic uncertainties are considered, the average code-based safety checking could end up being unconservative with respect to performance-based procedures when the number of records is small. However, it is shown that performance-based safety checking is possible with no extra structural analyses.

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