scholarly journals Dynamic Response Spectrum of Multi-Story Shear Frame Subjected to Moderate Ground Motion

2021 ◽  
Vol 14 (2) ◽  
pp. 71-79
Author(s):  
Assal Hussein
Keyword(s):  
Dynamic Response ◽  
Ground Motion ◽  
Response Spectrum ◽  
Response Spectra ◽  
Mode Shapes ◽  
Seismic Load ◽  
Seismic Zone ◽  
Maximum Displacement ◽  
Shear Frame ◽  
The Impact

Design structures to resist natural hazards is a vital issue to mitigate the impact of such threats. Earthquakes could lead to numerous injuries and infrastructure destruction. Specifically, when structures are not designed to resist seismic load.  This article presents dynamic analysis of four-story shear frame under moderate ground motion to determine the dynamic response. The proposed location of the considered frame is near Iraq-Iran border due to increase of seismic activities in last years. Structures in the considered seismic zone are essentially either residential or commercial buildings and not designed to resist seismic load, therefore structural system failure is probable. Simplified model is considered to determine response spectrum according to the International Building Code requirements. The algorithm of the analysis is developed using MATLAB® code to get mode shapes, response spectrum acceleration, maximum displacement, maximum shear forces, and modal participation mass at each story. The article develops design response spectra curve of Erbil city. Furthermore, the analysis results showed that first mode shape has more contribution than the other modes because higher percentage of the mass of the shear frame responds to the ground motion, and 88.53% of shear-frame mass is participating responds to the ground motion in the same mode

scholarly journals A Computationally Efficient Ground-Motion Selection Algorithm for Matching a Target Response Spectrum Mean and Variance

2011 ◽  
Vol 27 (3) ◽  
pp. 797-815 ◽  
Author(s):  
Nirmal Jayaram ◽  
Ting Lin ◽  
Jack W. Baker
Keyword(s):  
Ground Motion ◽  
Response Spectrum ◽  
Ground Motions ◽  
Structural Response ◽  
Response Spectra ◽  
Selection Algorithm ◽  
Target Response ◽  
Computationally Efficient ◽  
Mean And Variance ◽  
The Impact

Dynamic structural analysis often requires the selection of input ground motions with a target mean response spectrum. The variance of the target response spectrum is usually ignored or accounted for in an ad hoc manner, which can bias the structural response estimates. This manuscript proposes a computationally efficient and theoretically consistent algorithm to select ground motions that match the target response spectrum mean and variance. The selection algorithm probabilistically generates multiple response spectra from a target distribution, and then selects recorded ground motions whose response spectra individually match the simulated response spectra. A greedy optimization technique further improves the match between the target and the sample means and variances. The proposed algorithm is used to select ground motions for the analysis of sample structures in order to assess the impact of considering ground-motion variance on the structural response estimates. The implications for code-based design and performance-based earthquake engineering are discussed.

The motion and damping of buildings relative to seismic response spectra

1970 ◽  
Vol 60 (1) ◽  
pp. 231-259 ◽  
Author(s):  
John A. Blume
Keyword(s):  
Ground Motion ◽  
Fundamental Mode ◽  
Response Spectrum ◽  
Spectral Response ◽  
Time History ◽  
Response Spectra ◽  
Mode Shapes ◽  
System Response ◽  
Building Motion ◽  
Actual Response

abstract The response spectrum is very useful in dynamic analysis even though its use for multimass systems involves approximations as to modal combinations. It is especially useful in predicting effects of possible real earthquakes or of proposed nuclear detonations because it may be postulated or predicted much more readily than a complete time history of ground motion. The relationships of multimass system response—in terms of displacement, velocity, acceleration, force, shear, and moment—to elastic spectral response are given, together with examples taken from the AEC nuclear testing program in Nevada. The effects of relative building stiffnesses and stiffness taper on mode shape and thus on response are shown, as are the base shears relative to spectral response for several idealized fundamental mode shapes. A Spectral Response Reconciliation procedure is presented and demonstrated by which procedure spectral response is reconciled with measured real building motion to obtain damping or other data under actual response to ground motion of any intensity. Damping values of highrise buildings are determined by this procedure. Comparisons are made between 5 per cent damped response spectral values at the fundamental mode period of buildings and measured building motion.

scholarly journals A Multi-Objective Ground Motion Selection Approach Matching the Acceleration and Displacement Response Spectra

2018 ◽  
Vol 10 (12) ◽  
pp. 4659 ◽  
Author(s):  
Yabin Chen ◽  
Longjun Xu ◽  
Xingji Zhu ◽  
Hao Liu
Keyword(s):  
Ground Motion ◽  
Response Spectrum ◽  
Structural Response ◽  
Response Spectra ◽  
Computationally Efficient ◽  
Ground Motion Selection ◽  
Displacement Response ◽  
Rc Frames ◽  
Selection Approach ◽  
Displacement Response Spectra

For seismic resilience-based design (RBD), a selection of recorded time histories for dynamic structural analysis is usually required. In order to make individual structures and communities regain their target functions as promptly as possible, uncertainty of the structural response estimates is in great need of reduction. The ground motion (GM) selection based on a single target response spectrum, such as acceleration or displacement response spectrum, would bias structural response estimates leading significant uncertainty, even though response spectrum variance is taken into account. In addition, resilience of an individual structure is not governed by its own performance, but depends severely on the performance of other systems in the same community. Thus, evaluation of resilience of a community using records matching target spectrum at whole periods would be reasonable because the fundamental periods of systems in the community may be varied. This paper presents a GM selection approach based on a probabilistic framework to find an optimal set of records to match multiple target spectra, including acceleration and displacement response spectra. Two major steps are included in that framework. Generation of multiple sub-spectra from target displacement response spectrum for selecting sets of GMs was proposed as the first step. Likewise, the process as genetic algorithm (GA), evolvement of individuals previously generated, is the second step, rather than using crossover and mutation techniques. A novel technique improving the match between acceleration response spectra of samples and targets is proposed as the second evolvement step. It is proved computationally efficient for the proposed algorithm by comparing with two developed GM selection algorithms. Finally, the proposed algorithm is applied to select GM records according to seismic codes for analysis of four archetype reinforced concrete (RC) frames aiming to evaluate the influence of GM selection considering two design response spectra on structural responses. The implications of design response spectra especially the displacement response spectrum and GM selection algorithm are summarized.

scholarly journals Preliminary results of ground-motion characteristics

2012 ◽  
Vol 55 (4) ◽  
Author(s):  
Francesca Bozzoni ◽  
Carlo Giovanni Lai ◽  
Laura Scandella
Keyword(s):  
Ground Motion ◽  
Site Response ◽  
Response Spectrum ◽  
Field Tests ◽  
Response Spectra ◽  
Ground Acceleration ◽  
Preliminary Results ◽  
Emilia Earthquake ◽  
Particle Orbit ◽  
2012 Emilia Earthquake

The preliminary results are presented herein for the engineering applications of the characteristics of the ground motion induced by the May 20, 2012, Emilia earthquake. Shake maps are computed to provide estimates of the spatial distribution of the induced ground motion. The signals recorded at the Mirandola (MRN) station, the closest to the epicenter, have been processed to obtain acceleration, velocity and displacement response spectra. Ground-motion parameters from the MRN recordings are compared with the corresponding estimates from recent ground-motion prediction equations, and with the spectra prescribed by the current Italian Building Code for different return periods. The records from the MRN station are used to plot the particle orbit (hodogram) described by the waveform. The availability of results from geotechnical field tests that were performed at a few sites in the Municipality of Mirandola prior to this earthquake of May 2012 has allowed preliminary assessment of the ground response. The amplification effects at Mirandola are estimated using fully stochastic site-response analyses. The seismic input comprises seven actual records that are compatible with the Italian code-based spectrum that refers to a 475-year return period. The computed acceleration response spectrum and the associated dispersion are compared to the spectra calculated from the recordings of the MRN station. Good agreement is obtained for periods up to 1 s, especially for the peak ground acceleration. For the other periods, the spectral acceleration of the MRN recordings exceeds that of the computed spectra.<br />

Response spectral matching of horizontal ground motion components to an orientation-independent spectrum (RotDnn)

2020 ◽  
pp. 875529302097098
Author(s):  
Luis A Montejo
Keyword(s):  
Ground Motion ◽  
Response Spectrum ◽  
Time History ◽  
Response Spectra ◽  
Major Axis ◽  
Component Level ◽  
Nonlinear Characteristics ◽  
Target Spectrum ◽  
Horizontal Ground Motion ◽  
Median Spectrum

This article presents a methodology to spectrally match two horizontal ground motion components to an orientation-independent target spectrum (RotDnn). The algorithm is based on the continuous wavelet transform decomposition and iterative manipulation of the two horizontal components of a seed record. The numerical examples presented follow current ASCE/SEI 7 specifications and therefore maximum-direction spectra (RotD100) are used as target for the match. However, the proposed methodology can be used to match other RotDnn spectra, like the median spectrum (RotD50). It is shown that with the proposed methodology the resulting RotDnn from the modified horizontal components closely match the smooth target RotDnn spectrum, while the response spectrum for each horizontal component continue to exhibit a realistic jagged behavior. The response spectra variability at the component level within suites of spectrally matched motions was found to be of the same order than the variability measured in suites composed of amplitude scaled records. Moreover, the spectrally matched records generated preserved most of the characteristics of the seed records, including the nonlinear characteristics of the time history traces and the period-dependent major axis orientations.

Predictive Equations to Quantify the Impact of Spectral Matching on Ground Motion Characteristics

2016 ◽  
Vol 32 (1) ◽  
pp. 125-142 ◽  
Author(s):  
Clinton Carlson ◽  
Dimitrios Zekkos ◽  
Adda Athanasopoulos-Zekkos
Keyword(s):  
Ground Motion ◽  
Response Spectrum ◽  
Time History ◽  
Peak Ground Velocity ◽  
Spectral Matching ◽  
Predictive Equations ◽  
Earthquake Scenarios ◽  
Cumulative Absolute Velocity ◽  
Motion Characteristics ◽  
The Impact

Spectral matching, the process of modifying a seed acceleration time history in intensity and frequency content until its acceleration response spectrum matches a target spectrum, is used extensively in practice. Predictive equations that quantify the impact of spectral matching on the peak ground velocity, peak ground displacement, Arias intensity, and cumulative absolute velocity of a scaled seed time history have been developed and validated on the basis of thousands of matched motions, three different earthquake scenarios, and numerous target spectra. It is found that spectral mismatch is the most critical factor affecting the changes in ground motion characteristics. The technique used for modification (e.g., time domain or frequency domain) is in many cases not critical. Based on the results, recommendations in order to minimize the impact of matching on the ground motion characteristics are provided.

Analytical Determination of Shock Response Spectra for an Impulse-Loaded Proportionally Damped System

Volume 1 ◽  
2004 ◽  
Author(s):  
R. David Hampton ◽  
Nathan S. Wiedenman ◽  
Ting H. Li
Keyword(s):  
Transient Response ◽  
Shock Loading ◽  
Response Spectrum ◽  
Response Spectra ◽  
Analytical Determination ◽  
System Response ◽  
Mechanical Shock ◽  
Shock Response ◽  
Mass Spring ◽  
The Impact

Many military systems must be capable of sustained operation in the face of mechanical shocks due to projectile or other impacts. The most widely used method of quantifying a system’s vibratory transient response to shock loading is called the shock response spectrum (SRS). The system response for which the SRS is to be determined can be due, physically, either to a collocated or to a noncollocated shock loading. Taking into account both possibilities, one can define the SRS as follows: the SRS presents graphically the maximum transient response (output) of an imaginary ideal mass-spring-damper system at one point on a flexible structure, to a particular mechanical shock (input) applied to an arbitrary (perhaps noncollocated) point on the structure, as a function of the natural frequency of the imaginary mass-spring-damper system. For a response point sufficiently distant from the impact area, many Army platforms (such as vehicles) can be accurately treated as linear systems with proportional damping. In such cases the output due to an impulsive mechanical-shock input can be decomposed into exponentially decaying sinusoidal components, using normal-mode orthogonalization. Given a shock-induced loading comprising such components, this paper provides analytical expressions for the various common SRS forms. The analytical approach to SRS-determination can serve as a verification of, or an alternative to, the numerical approaches in current use for such systems. No numerical convolution is required, because the convolution integrals have already been accomplished analytically (and exactly), with the results incorporated into the algebraic expressions for the respective SRS forms.

Analysis of Dynamic Response of High Rockfill Embankment under Seismic Loads

2010 ◽  
Vol 163-167 ◽  
pp. 4363-4366 ◽  
Author(s):  
Cheng Zhong Yang
Keyword(s):  
Dynamic Response ◽  
Seismic Design ◽  
Response Spectrum ◽  
Element Model ◽  
Security Evaluation ◽  
Seismic Loads ◽  
Maximum Displacement ◽  
Maximum Acceleration ◽  
Embankment Slope ◽  
The Right

To reveal the stress-strain properties of Gangou high rockfill embankment with 71m high under seismic loads and provide the reference for its security evaluation and the seismic reinforcement design. By simplifying the high rockfill embankment as the plane problem, establishing two-dimensional finite element model, inputting EL Centro and applying seismic response spectrum method, the dynamic response of high rockfill embankment under seismic loads were simulated. The results show that: With the increase of embankment height, the dynamic response presents increasing tendency; The maximum displacement occurs on the right side of the embankment top, t1474he maximum acceleration appears at the middle of embankment slope. From the view of seismic design, the right side of the embankment top and the middle of embankment slope are the focus of seismic design.

scholarly journals Seismic Analysis of Irregular Building on Hilly Area

2021 ◽  
Vol 1 (1) ◽  
pp. 1-7
Author(s):  
Anjeet Singh Chauhan ◽  
◽  
Rajiv Banerjee
Keyword(s):  
Dynamic Response ◽  
Flat Surface ◽  
Seismic Analysis ◽  
Response Spectrum ◽  
Seismic Loading ◽  
Population Increase ◽  
Seismic Zone ◽  
Severe Damage ◽  
Rc Buildings ◽  
Sloping Ground

The RC buildings' construction has increased in the preferred location of north & eastern hilly areas during the last few decades due to population increase, urbanization, and tourists. The buildings located in the hilly areas are more susceptible to seismic loading as compared to the location of the flat surface building. The shape of the building on the sloping ground differs from the flat surface situated buildings. So, the construction of the building on hilly areas are irregular both vertically & horizontally, thus this type of building is susceptible to severe damage when applied to the seismic condition. The column of the base storey having unequal height due to sloping ground. In this study, the behaviour of a 10 storey stepback building with mass and diaphragm irregularity on the sloping ground is analysed in seismic zone V by Response Spectrum. The analysis of the building is carried out by Etabs software as per IS 1893:2016 to compare the building based on their dynamic response and also identify the vulnerability frame in the sloping ground.

scholarly journals Effectiveness of fluid viscous damper for steel frame building subjected to earthquake load

2021 ◽  
Vol 263 ◽  
pp. 03015
Author(s):  
Thanh Binh Pham ◽  
Ngoc Quang Vu
Keyword(s):  
Dynamic Response ◽  
Time History ◽  
Steel Frame ◽  
Frame Structure ◽  
Seismic Load ◽  
Viscous Damper ◽  
Maximum Displacement ◽  
Fluid Viscous Damper ◽  
Frame Building ◽  
Earthquake Load

Since the appearance of the first modern multistories buildings, besides the demand of ensuring the bearing capacity, one of the urgent problems facing the engineer is to do how to design structure to ensure the requirements of normal use such as displacement, motion acceleration within permissible limits. There exist many methods to reduce these response of structure under lateral load. Among these, using fluid viscous damper (FVD) is one of the most applied equipment because of its simplicity. This paper presents the examination of eight-story steel frame structure subjected to seismic load. The FVD system is defined in Etabs with link properties. In each story, four dampers are located in each direction of plan, with two on each side of the center of stiffness of the story. The time history analysis was conducted to study the structure subjected to seimic load collected from the function library of program Etabs. The effect of FVD system was determined by the dynamic response of the building and displacement indexes such as maximum displacement of roof, story drift ratio. The results show that, all the dynamic response characters of structure were decreased significantly when providing the FVD to it.

Sign in / Sign up

Export Citation Format

Share Document