On the Use of Design Spectrum Compatible Time Histories

1995 ◽  
Vol 11 (1) ◽  
pp. 111-127 ◽  
Author(s):  
Farzad Naeim ◽  
Marshall Lew
Keyword(s):  
Response Spectrum ◽  
Time History ◽  
Design Spectrum ◽  
Analysis And Design ◽  
Motion Time ◽  
Expected Performance ◽  
Earthquake Resistant ◽  
Earthquake Resistant Structures ◽  
Time Histories ◽  
Design Earthquake

To a designer of a nonlinear structure, there is nothing more attractive than a real or fictitious ground motion time history whose response spectrum matches the target design spectrum. Frequency-domain scaled, design spectrum compatible time histories (DSCTH) are widely used in analysis and design of special structures, particularly seismic-isolated buildings. Their use has been even mandated by some code provisions. At the first glance, it seems that DSCTH records furnish designers of earthquake resistant structures with a consistency and compatibility bridge between the two very different worlds of elastic and inelastic response. Closer examination, as presented in this paper, reveal however that there are significant potential problems associated with uncontrolled use of DSCTH records in seismic design. It is shown that the use of design spectrum compatible time histories can lead to exaggeration of displacement demand and energy input. This in turn can distort the expected performance of the structure when subjected to design earthquake ground motions.

scholarly journals Unique Method for Generating Design Earthquake Time Histories

2008 ◽  
Author(s):  
R. E. Spears
Keyword(s):  
Response Spectrum ◽  
Low Frequency ◽  
Time History ◽  
Response Spectra ◽  
Cumulative Energy ◽  
Time Histories ◽  
Displacement Response Spectra ◽  
Unique Method ◽  
Design Earthquake ◽  
Velocity Response Spectrum

A method has been developed which takes a seed earthquake time history and modifies it to produce given design response spectra. It is a multi-step process with an initial scaling step and then multiple refinement steps. It is unique in the fact that both the acceleration and displacement response spectra are considered when performing the fit (which primarily improves the low frequency acceleration response spectrum accuracy). Additionally, no matrix inversion is needed. The features include encouraging the code acceleration, velocity, and displacement ratios and attempting to fit the pseudo velocity response spectrum. Also, “smoothing” is done to transition the modified time history to the seed time history at its start and end. This is done in the time history regions below a cumulative energy of 5% and above a cumulative energy of 95%. Finally, the modified acceleration, velocity, and displacement time histories are adjusted to start and end with an amplitude of zero (using Fourier transform techniques for integration).

Wavelet Packet Characterization of Scenario Earthquake Ground Motions

2017 ◽  
Vol 11 (03) ◽  
pp. 1750006
Author(s):  
Ajin Baby ◽  
Manish Shrikhande
Keyword(s):  
Ground Motion ◽  
Prediction Models ◽  
Response Spectrum ◽  
Wavelet Packet ◽  
Time History ◽  
Motion Prediction ◽  
Ground Motion Prediction ◽  
Scenario Earthquake ◽  
Motion Time ◽  
Time Histories

With increased emphasis on performance-based seismic design, the need for appropriate ground motion time histories for use in nonlinear dynamic analyses is felt accutely. However, it is generally not possible to get a suitable recorded time history consistent with the estimated hazard at a specific site. The ground motion prediction models are therefore derived/developed from a statistical analysis of recorded ground motion for a variety of source and site conditions to address this need. Most often, the ground motion prediction models are developed to model the response spectrum amplitudes at a set of natural periods and the ground motion time history, if required, is then generated to be consistent with this predicted response spectrum. These simulated time histories often lack in modeling the wave arrivals and temporal variation in the distribution of energy with respect to frequency. In this paper, we present a wavelet-based ground motion prediction model for directly generating ground motion time history that is consistent with the postulated scenario earthquake at a site.

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.

Method for Generating Design Earthquake Time Histories With an Emphasis on Maintaining Phasing

2010 ◽  
Author(s):  
R. E. Spears
Keyword(s):  
Response Spectrum ◽  
Time History ◽  
Strong Motion ◽  
Low Energy ◽  
Design Response Spectrum ◽  
Multistep Process ◽  
Time Histories ◽  
Design Earthquake ◽  
Original Time

A method has been developed which takes a seed earthquake time history and modifies it to produce a time-history with a given design response spectrum. It is a multistep process with an emphasis on maintaining phasing during the strong motion duration. Initially, the seed earthquake time history is broken into a series of separate time histories which added together produce the original time history. Each separate time history is drift corrected using modifications only outside the strong motion duration of the seed earthquake time history. This allows the separate time histories to be individually scaled to improve the response spectrum match while the phase of the motion during the strong motion duration remains unchanged. To further improve the design response spectrum match, low cycle, low energy waves are added. This is primarily to control the response at higher frequency. These waves are tuned to improve the response at existing peaks.

Application of Earthquake Resistance Analysis Technique in the Design of Constructional Engineering

2013 ◽  
Vol 756-759 ◽  
pp. 4482-4486
Author(s):  
Chun Gan ◽  
Xue Song Luo
Keyword(s):  
Response Spectrum ◽  
Structural Response ◽  
Time History ◽  
Economic Losses ◽  
Element Analysis ◽  
Architectural Engineering ◽  
Analysis Technique ◽  
History Analysis ◽  
Earthquake Resistant ◽  
History Of

In recent years, frequent earthquakes have caused great casualties and economic losses in China. And in the earthquake, damage of buildings and the collapse is the main reason causing casualties. Therefore, in the design of constructional engineering, a seismicity of architectural structure is the pressing task at issue. Through time history analysis method, this paper analyzes the time history of building structural response and then it predicts the peak response of mode by response spectrum analysis. Based on this, this paper constructs a numerical simulation model for the architecture by using finite element analysis software SATWE. At the same time, this paper also calculates the structure seismic so as to determine the design of each function structure in architectural engineering design and then provides reference for the realization of earthquake-resistant building.

Use of RVT for Computation of In-Structure Response Spectra and Peak Responses and Comparison to Time History and Response Spectrum Analysis

2018 ◽  
Vol 34 (4) ◽  
pp. 1913-1930 ◽  
Author(s):  
Irmela Zentner
Keyword(s):  
Response Spectrum ◽  
Structural Response ◽  
Time History ◽  
Strong Motion ◽  
Response Spectra ◽  
Combination Rules ◽  
Floor Response Spectra ◽  
Power Spectral ◽  
Time Histories ◽  
Definition Of

The random vibration theory offers a framework for the conversion of response spectra into power spectral densities (PSDs) and vice versa. The PSD is a mathematically more suitable quantity for structural dynamics analysis and can be straightforwardly used to compute structural response in the frequency domain. This allows for the computation of in-structure floor response spectra and peak responses by conducting only one structural analysis. In particular, there is no need to select or generate spectrum-compatible time histories to conduct the analysis. Peak response quantities and confidence intervals can be computed without any further simplifications such as currently used in the response spectrum method, where modal combination rules have to be derived. In contrast to many former studies, the Arias intensity-based definition of strong-motion duration is adopted here. This paper shows that, if the same definitions of strong-motion duration and modeling assumptions are used for time history and RVT computations, then the same result can be expected. This is illustrated by application to a simplified model of a reactor building.

scholarly journals Seismic Effect on Design of Residential Multi-Storey Building (Stilt+17 Floors) In Zone-Iii and Zone-Iv using Etabs

2019 ◽  
Vol 8 (6) ◽  
pp. 4662-4666 ◽  
Keyword(s):  
Residential Building ◽  
Seismic Effect ◽  
3 Dimensional ◽  
Analysis And Design ◽  
Earthquake Resistant ◽  
Building Systems ◽  
Earthquake Resistant Structures ◽  
Effective Design ◽  
Storey Building

Structural Analysis is a branch which involves in the determination of behaviour of structures so as to predict the responses of different structural components due to impact of loads. ETABS (Extended 3 Dimensional Analysis of Building Systems) is a software which is incorporated with all the major analysis engines that are static, dynamic, linear and non-linear etc. The main purpose of this paper is to design Multi-storeyed building with a static method, since an effective design and construction of earthquake resistant structures are important all over the world. This project deals with seismic effect on “analysis, design and comparison of multi-storey residential building of stilt+17 floors in zone-iii and zone-iv using ETABS”. It is an attempt to study the behaviour of a residential building using ETABS in different zones and areas with same soil bearing capacity. Analysis and design has been carried out as per IS1843-2002 (Part-1) and IS 456:2000. The more drifts and displacements have been noticed in zone 4 compared to zone 3

scholarly journals Seismic Design of Steel Frames Equipped by Control Devices

2014 ◽  
Vol 8 (1) ◽  
pp. 300-309 ◽  
Author(s):  
Nikos G. Pnevmatikos ◽  
George Hatzigeorgiou
Keyword(s):  
Response Spectrum ◽  
Control Analysis ◽  
Control Force ◽  
Design Spectrum ◽  
Elastic Range ◽  
Design Philosophy ◽  
Control Devices ◽  
Controlled Structure ◽  
Design Earthquake ◽  
Control Forces

The design philosophy of EC8 is to ensure that in the event of the design earthquake, human lives are protected and no collapse will occur, while extended damages will be observed. This is achieved by ductility and capacity design. This design philosophy drives to an additional cost for repairing damage of structures. On the other hand, it is costly and uneconomic to design structures behaving in elastic range, especially under high level of earthquake excitation. An alternative direction to this strategy, which is examined in this paper, is to design a controlled structure capable to resist a design earthquake loads, remaining in elastic range and thus without damage. The idea behind this philosophy is that one portion of earthquake loading will be resisted by a control system while the rest will be resisted by the structure. The structure, initially, is analyzed and designed according to the current codes. The elastic and design earthquake forces are first calculated according to the elastic and the design spectrum. The required control forces are calculated as the difference between elastic and design forces. The maximum value of capacity of control devices is then compared with the required control force. If the capacity of the controlled devices is higher than the required control force then the control devices are accepted and installed to the structure. Then, the structure is designed according to the design forces. In the case where the maximum available control device capacity is lower than the demanded control force then an additional portion of control forces should be resisted by the building. In that case, an iterative procedure is proposed and a scale factor, 􀀁, that reduces the elastic response spectrum to a new design spectrum, is calculated. The structure is redesigned based on the new design spectrum and then the devices are installed to the structure. The proposed procedure imposes that the controlled structure will behave elastically for the design earthquake and no damage will occur, consequently no additional repair cost will be needed. An initial cost of buying and installing the control devices is required. In order to ensure that the controlled structure behaves elastically, a dynamic control analysis with saturation and time delay control is performed. Following the proposed procedure the numerical results show that the structure remains in elastic and no damage occurs.

ANALYSIS AND DESIGN OF MULTI-STOREY STEEL STRUCTURES WITH IRRIGATION TO TORQUE ACCORDING TO 2018 EARTHQUAKE REGULATIONS

2021 ◽  
Vol 0 (15) ◽  
pp. 0-0
Author(s):  
Fahım Ahmad NOWBAHARI ◽  
Elif AĞCAKOCA
Keyword(s):  
Steel Structure ◽  
Steel Structures ◽  
Seismic Load ◽  
Finite Element Program ◽  
Analysis And Design ◽  
Earthquake Resistant Structures ◽  
Cross Member ◽  
Element Program ◽  
The Cross ◽  
Design Earthquake

When observing the consequences of earthquakes, it is accepted that earthquakes are one of the most dangerous natural disasters in the world. Therefore, special engineering methods are used to explore and analyze the effects of earthquakes on structures and to design earthquake resistant structures accordingly. In applying these methods, it is important to investigate the irregularities in the carrier system correctly. There are six irregularities in the Turkish Building Earthquake Code (TBDY-2018), one of the most important of which is A1 Torsional Irregularity [TBDY 2018]. In this article, considering TBDY 2018, the dynamic behaviour of structures with different ratios of torsional irregularity in multi-storey steel structures is examined. In a 10-storey steel structure with the same purpose and size, four type models were produced using the central inverted V cross member and changing the cross positions. The Equivalent Seismic Load Method is used in the analysis. Structural analyzes were performed with the "ETABS" finite element program. As a result of these studies; The displacements obtained from the structural analysis of 4 models with different torsional irregularity coefficients due to the cross member placement in various places in 4 buildings with the same dimensions were calculated by the Equivalent Seismic Load method.

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