scholarly journals PEAK VERTICAL GROUND ACCELERATION PREDICTION USING JMA-87 TYPE ACCELEROMETER DATA

1995 ◽  
Vol 23 ◽  
pp. 97-100
Author(s):  
Laurensius Dicky ◽  
Fumio Yamazaki ◽  
Gilbert L. Molas ◽  
Tsuneo Katayama
Keyword(s):  
Accelerometer Data ◽  
Ground Acceleration ◽  
Vertical Ground

Parametric effect of vertical ground acceleration on the earthquake response of elastic structures

1990 ◽  
Vol 17 (2) ◽  
pp. 209-217 ◽  
Author(s):  
S. T. Ariaratnam ◽  
K. C. K. Leung
Keyword(s):  
Ground Motion ◽  
Structural Model ◽  
Lateral Displacement ◽  
Stochastic Modelling ◽  
Tall Building ◽  
Earthquake Excitation ◽  
Restoring Force ◽  
Ground Acceleration ◽  
Linear Elastic ◽  
Vertical Ground

An analytical procedure is presented for the calculation of the statistical properties of the response of a linear elastic tall building under earthquake excitation. Emphasis is placed on the effect of the vertical ground motion. The restoring force in each story of the structural model is assumed to arise from the bending deformation of the columns whose rigidities are subjected to a general reduction due to the combined action of gravitational forces and the random variations due to vertical ground acceleration. Since earthquakes are random phenomena, stochastic modelling of ground motion seems appropriate. Both the vertical and the horizontal accelerations are treated as amplitude-modulated Gaussian random processes. With these models, the techniques developed herein, using the concept of Markov processes and Itô's stochastic differential equations, may be applied. To illustrate the application of the method, numerical results are presented for a six-story building. For computational purposes, the structural properties are evaluated using the finite element method. Within the limit of linear elastic deformation, the vertical ground acceleration is shown to be capable of causing only a slight increase of 0.08% in the lateral displacement for this moderately tall building. The percentage is expected to be larger for a taller building and much larger when the deformations exceed the elastic limit. Key words: earthquake excitation, elastic frames, random vibration, Markov process, dynamic response.

Ground-motion intensity inferred from upthrow of boulders during the 1984 Western Nagano Prefecture, Japan, earthquake

1992 ◽  
Vol 82 (1) ◽  
pp. 44-60
Author(s):  
Tatsuo Ohmachi ◽  
Saburoh Midorikawa
Keyword(s):  
Numerical Simulations ◽  
Ground Motion ◽  
Distinct Element ◽  
Field Measurements ◽  
Shaking Table ◽  
Ground Acceleration ◽  
Nagano Prefecture ◽  
Vibration Experiment ◽  
Vertical Ground ◽  
Table Motion

Abstract To interpret observations of the upthrow of boulders followed by their remarkable displacement during the 1984 Western Nagano Prefecture, Japan, earthquake, shaking-table experiments, field measurements, and numerical simulations on the upthrow were conducted. First, upthrow of objects was produced during a shaking-table vibration experiment in which table motion was in the horizontal direction only. Next, after field measurements on the ground and boulders were carried out to determine the parameters in the numerical simulations, a series of numerical simulations was conducted using the distinct element method. Both the experimental and numerical approaches not only resulted in reinforcement of Newmark's argument (1973) that the upthrow does not necessarily indicate vertical ground acceleration greater than that of gravity, but further extended it to quantitative assessment of ground-motion intensity.

Accelerograms of the 1978 Tabas, Iran, Earthquake

1986 ◽  
Vol 2 (3) ◽  
pp. 635-651 ◽  
Author(s):  
Mansour Niazi
Keyword(s):  
Main Shock ◽  
Epicentral Distance ◽  
Source Region ◽  
Response Spectra ◽  
Rupture Surface ◽  
Ground Acceleration ◽  
Complex Source ◽  
Vertical Ground ◽  
Elastic Design ◽  
Tabas Earthquake

Three triaxial sets of accelerograms recorded in the near source region (within 50 km epicentral distance) of the September 16, 1978, Tabas earthquake (Ms 7.4 -7.7) are of great engineering importance. The distances of the recording sites from the nearest approach of the rupture surface are approximately 3, 17, and 28 km for Tabas, Dayhook and Boshrooyeh stations, respectively. The measured horizontal peak ground accelerations of 0.94 and 0.88 g at Tabas are higher than previously estimated. The peak vertical ground acceleration recorded at this station is 0.74 g. The normalized response spectra at these three stations are consistent with the Newmark-Hall elastic design spectra, suggesting that the latter adequately represent the spectral amplification factors at frequencies above 1 Hz. The main shock accelerogram at Dayhook exhibits at least three distinct events as indication of a complex source behavior. The widened spacing of these events on the Dayhook records further confirms that the rupture front moved northwestward away from this station and towards Tabas. The measured S minus trigger times at Tabas, Dayhook and Boshrooyeh stations are in conflict with the teleseismically determined epicenter, requiring it to move approximately 30 km to the southwest to about 33° 17′N, 57° 09′ E.

Performance of engineered timber structures in the Canterbury earthquakes

2011 ◽  
Vol 44 (4) ◽  
pp. 394-401 ◽  
Author(s):  
Andrew Buchanan ◽  
David Carradine ◽  
Justin Jordan
Keyword(s):  
New Zealand ◽  
Structural Damage ◽  
Lateral Spreading ◽  
Life Safety ◽  
Timber Structures ◽  
Ground Acceleration ◽  
Different Types ◽  
Vertical Ground ◽  
Short Time ◽  
Water Tanks

The September 2010 and February 2011 earthquakes in Canterbury, New Zealand resulted in significant ground excitations that caused severe geotechnical effects and widespread structural damage. This paper outlines the various forms of damage to different types of engineered timber structures, including timber water tanks. Most of the damage resulted from lateral spreading and high levels of horizontal and vertical ground acceleration. The response of these building types is discussed. Engineered timber structures generally performed well both for life safety and serviceability, with most buildings ready for occupation within a short time following the events.

scholarly journals The City of Erasure

2021 ◽  
Author(s):  
◽  
Rory Wilson-Cartwright
Keyword(s):  
Personal Experience ◽  
Urban Environments ◽  
Architectural Drawings ◽  
Ground Acceleration ◽  
The Third ◽  
The Earth ◽  
Vertical Ground ◽  
Complex Phenomena ◽  
The City ◽  
Design Experiments

<p><b>In 2011 the Banks Peninsula experienced an unprecedented natural disaster. This disaster, anearthquake, measured larger in vertical ground acceleration that any recorded prior. As youcan imagine, the architecture surrounding the epicentre was devastated. It was not just build- ings that were lost, but all of their associations; memories, experiences, intimate and personal objects. Life was erased from the surface of the earth.</b></p> <p>Amongst the chaos, trauma and destruction, it was a particular personal experience that actedas the catalyst for this thesis. After they demolished our home, I struggled to recall the eventsthat took place within its walls. I could not separate the real from the imagined. It was only when I stumbled upon the working drawings that I was able to position myself within my memories and reflect on the erasure that caused my memories to change. This experience led me to contemplate, what role do memories have on our understandings of a city? How can architectural drawings facilitate these relationships?</p> <p>This thesis does not set out to fix the issues that natural disasters cause; rather, it aims to further our understanding of therole that memory plays in our perceptions of urban environments. It uses the implications of erasure as material for speculative architectural investigations. These investigations are achieved through three clear sets of design experiments ascending in scale and complexity; the first, an installa- tion, the second, a series of medium-scale architectures, and the third, a large public building. These design experiments use speculative architectural drawings as a translational tool for ephemeral phenom- ena, helping to bridge the divide between cerebral and operational perceptions. This research aims to further our understanding of these complex phenomena in order to expand upon our own spatial and architec- tural intelligence through explorations of memory and erasure.</p>

scholarly journals Seismic Response of Ground Cylindrical and Elevated Conical Reinforced Concrete Tanks

2021 ◽  
Author(s):  
Mehdi Moslemi
Keyword(s):  
Finite Element ◽  
Dynamic Behaviour ◽  
Cone Angle ◽  
Tank Wall ◽  
Frequency Content ◽  
Ground Acceleration ◽  
Earthquake Frequency ◽  
Wall Flexibility ◽  
Elevated Tanks ◽  
Vertical Ground

In this study, the seismic performance of concrete ground-supported cylindrical as well as liquid-filled elevated water tanks supported on concrete shaft is evaluated using the finite element method. The effects of a wide spectrum of parameters such as liquid sloshing, tank wall flexibility, vertical ground acceleration, tank aspect ratio, base fixity, and earthquake frequency content on dynamic behaviour of such structures are examined. Furthermore, the adequacy of current practice in seismic analysis and design of liquid containing structures is investigated. A comprehensive parametric study covering a wide range of tank capacities and aspect ratios found in practice today is also carried out on elevated tanks. Two different innovative strategies to reduce the seismic response of elevated tanks are examined, in the first strategy the inclined cone angle of the lower portion of the vessel is increased while in the second strategy the supporting shaft structure is isolated either from the ground or the vessel mounted on top. The results of this study show that capability of the proposed finite element technique. Using this method, the major aspects in the fluid-structure interaction problems including wall flexibility, sloshing motion, damping properties of fluid domain, and the individual effects of impulsive and convective terms can be considered. The effects of tank wall flexibility, vertical ground acceleration, base fixity, and earthquake frequency content are found to be significant on the dynamic behaviour of liquid tanks. The parametric study indicates that the results can be utilized with high level of accuracy in seismic design applications for conical elevated tanks. This study further shows that increasing the cone angle of the vessel can result in a significant reduction in seismically induced forces of the tank, leading to an economical design of the shaft structure and the foundation system. It is also concluded that the application of passive control devices to conical elevated tanks offers a substantial benefit for the earthquake-resistant design of such structures.

Vertical Ground Motion Model for PGA, PGV, and Linear Response Spectra Using the NGA-West2 Database

2016 ◽  
Vol 32 (2) ◽  
pp. 979-1004 ◽  
Author(s):  
Yousef Bozorgnia ◽  
Kenneth W. Campbell
Keyword(s):  
Ground Motion ◽  
Response Spectra ◽  
Peak Ground Velocity ◽  
Motion Model ◽  
Acceleration Response ◽  
Ground Acceleration ◽  
Ground Motion Model ◽  
Crustal Earthquakes ◽  
Active Tectonic ◽  
Vertical Ground

We summarize the development of the NGA-West2 Bozorgnia-Campbell empirical ground motion model (GMM) for the vertical components of peak ground acceleration (PGA), peak ground velocity (PGV), and 5%-damped elastic pseudo-absolute acceleration response spectra (PSA) at vertical periods ranging from 0.01 s to 10 s. In the development of the vertical GMM, similar to our 2014 horizontal GMM, we used the extensive PEER NGA-West2 worldwide database. We consider our new vertical GMM to be valid for shallow crustal earthquakes in active tectonic regions for magnitudes ranging from 3.3 to 7.5–8.5, depending on the style of faulting, and for distances as far as 300 km from the fault.

scholarly journals Nonlinear seismic response of ground supported cylindrical reinforced concrete tanks

2021 ◽  
Author(s):  
Maryam Rafieeraad
Keyword(s):  
Seismic Behavior ◽  
Time History ◽  
Material Nonlinearity ◽  
Ground Acceleration ◽  
Response Modification Factor ◽  
R Factor ◽  
Earthquake Frequency ◽  
Modification Factor ◽  
Vertical Ground ◽  
Strength And Ductility

Seismic behavior of Liquid Containing Structures has been studied for decades. Being able to have these structures functioning during and after an earthquake is imperative for well-being of a society hence importance of their design. Response Modification Factor known as “R factor” is one of the key parameters in seismic design. However, in case of LCS’s, a justifiable guideline to determine the R factor is yet to be developed and current codes have utilized empirical values in design of these structures. The design intend for LCS’s is to meet the serviceability limits as opposed to life safety and collapse prevention which is the case of design of buildings. This study aims to investigate the effect of various parameters such as material nonlinearity, tank dimensions, base condition, concrete compressive strength, characteristics of seismic excitation records on the seismic behavior of concrete tanks. In this study, a finite element method is developed to investigate the seismic behavior of circular ground supported reinforced concrete tanks. First, the accuracy of current practice is investigated by employing the analytical and numerical methods, experimental studies. Finite element technique and pushover analysis are utilized to set up the pushover curve and achieve over-strength and ductility factors. The response modification factor (R) is then evaluated based on the nonlinear static analysis. Second, using the nonlinear dynamic analysis (time-history), the seismic behavioral aspects of full liquid tanks are studied taking into account the material nonlinearity, wall flexibility, effect of impulsive component, fluid-surface interaction and vertical ground acceleration. Thereafter, a parametric study is conducted to study the influence of tank dimensions, base fixity conditions and earthquake frequency content on the response modification factor. This study shows the over-strength and ductility factor of RC ground-supported tanks are significantly influence by tank size, height, height/diameter ratio and fundamental period. Also, fixed based tanks and shallow tanks have higher R values compared to hinged based and tall tanks respectively. The time history results show that the effect of material nonlinearity, vertical ground acceleration, base condition and earthquake frequency content on the dynamic behavior of liquid ground supported tanks is significant.

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