scholarly journals Seismic rocking effects on a mine tower under induced and natural earthquakes

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Piotr Adam Bońkowski ◽  
Juliusz Kuś ◽  
Zbigniew Zembaty
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Ground Surface ◽  
Tall Buildings ◽  
Earthquake Ground Motion ◽  
Seismic Action ◽  
Seismic Effects ◽  
Copper Ore ◽  
Rotational Components ◽  
Natural Earthquakes

AbstractRecent research in engineering seismology demonstrated that in addition to three translational seismic excitations along x, y and z axes, one should also consider rotational components about these axes when calculating design seismic loads for structures. The objective of this paper is to present the results of a seismic response numerical analysis of a mine tower (also called in the literature a headframe or a pit frame). These structures are used in deep mining on the ground surface to hoist output (e.g. copper ore or coal). The mine towers belong to the tall, slender structures, for which rocking excitations may be important. In the numerical example, a typical steel headframe 64 m high is analysed under two records of simultaneous rocking and horizontal seismic action of an induced mine shock and a natural earthquake. As a result, a complicated interaction of rocking seismic effects with horizontal excitations is observed. The contribution of the rocking component may sometimes reduce the overall seismic response, but in most cases, it substantially increases the seismic response of the analysed headframe. It is concluded that in the analysed case of the 64 m mining tower, the seismic response, including the rocking ground motion effects, may increase up to 31% (for natural earthquake ground motion) or even up to 135% (for mining-induced, rockburst seismic effects). This means that not only in the case of the design of very tall buildings or industrial chimneys but also for specific yet very common structures like mine towers, including the rotational seismic effects may play an important role.

Seismic response and retrofit of industrial brick masonry chimneys

1992 ◽  
Vol 19 (1) ◽  
pp. 117-128 ◽  
Author(s):  
A. Ghobarah ◽  
T. Baumber
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Strong Motion ◽  
Brick Masonry ◽  
Wind Loading ◽  
Earthquake Ground Motion ◽  
Lumped Mass ◽  
Mass System ◽  
Higher Modes ◽  
Recent Earthquakes

During recent earthquakes, the documented cases of collapsed unreinforced brick masonry industrial chimneys are numerous. Observed modes of structural failure are either total collapse or sometimes collapse or damage of the top third of the structure. The objective of this study is to analyze and explain the modes of observed failure of masonry chimneys during earthquake events, and to evaluate two retrofit systems for existing chimneys in areas of high seismicity. The behaviour of the masonry chimney, when subjected to earthquake ground motion, was modelled using a lumped mass system. Several actual strong motion records were used as input to the model. The shear, moment, and displacement responses to the earthquake ground motion were evaluated for various chimney configurations. It was found that the failure of the chimney at its base is the result of the fundamental mode of vibration. Failure at the top third of the structure due to the higher modes of vibration is possible when the chimney is subjected to high frequency content earthquakes. Higher modes, which are normally not of concern under wind loading, were shown to be critical in seismic design. Post-tensioning and the reinforcing steel cage were found to be effective retrofit systems. Key words: masonry, chimneys, behaviour, analysis, design, retrofit, dynamic, earthquakes, seismic response.

Estimation of Propagation Direction of Earthquake Ground Motion near Ground Surface Based on Array Observation Data

2011 ◽  
Vol 71-78 ◽  
pp. 1354-1359
Author(s):  
Zhong Yuan Yang
Keyword(s):  
Ground Motion ◽  
Structural Model ◽  
Three Dimensional ◽  
Estimation Method ◽  
Ground Surface ◽  
Horizontal Layer ◽  
Earthquake Ground Motion ◽  
Observation Data ◽  
Three Dimension ◽  
Layer Velocity

The three-dimensional propagation directions of earthquake ground motion near ground surface are estimated for eight earthquakes. By the NIOM method, three dimension (3-D) oriental angles are resulted in determining the arrival time of an incident wave and a reflectiveed wave. In this study, the estimation method of 3-D propagation directions is developed rationally and confirmed reliably with the independent data of Chiba array in Japan. The propagation directions are equivalent numerically to the geographical position of plural spots in horizontal and vertical, and the theoretical result obtained by the structural model of global horizontal layer velocity.

STOCHASTIC SEISMIC RESPONSE OF BASE-ISOLATED BUILDINGS

2013 ◽  
Vol 05 (01) ◽  
pp. 1350006 ◽  
Author(s):  
C. JACOB ◽  
K. SEPAHVAND ◽  
V. A. MATSAGAR ◽  
S. MARBURG
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Probability Distributions ◽  
Ground Motions ◽  
Earthquake Ground Motion ◽  
Response Analysis ◽  
Motion Model ◽  
Stochastic Response ◽  
Ground Motion Model ◽  
Stochastic Seismic Response

The stochastic response of base-isolated building considering the uncertainty in the characteristics of the earthquakes is investigated. For this purpose, a probabilistic ground motion model, for generating artificial earthquakes is developed. The model is based upon a stochastic ground motion model which has separable amplitude and spectral non-stationarities. An extensive database of recorded earthquake ground motions is created. The set of parameters required by the stochastic ground motion model to depict a particular ground motion is evaluated for all the ground motions in the database. Probability distributions are created for all the parameters. Using Monte Carlo (MC) simulations, the set of parameters required by the stochastic ground motion model to simulate ground motions is obtained from the distributions and ground motions. Further, the bilinear model of the isolator described by its characteristic strength, post-yield stiffness and yield displacement is used, and the stochastic response is determined by using an ensemble of generated earthquakes. A parametric study is conducted for the various characteristics of the isolator. This study presents an approach for stochastic seismic response analysis of base-isolated building considering the uncertainty involved in the earthquake ground motion.

On the design of a dense array to extract rotational components of earthquake ground motion

2016 ◽  
Vol 15 (3) ◽  
pp. 827-860 ◽  
Author(s):  
Dhiman Basu ◽  
Andrew S. Whittaker ◽  
Michael C. Constantinou
Keyword(s):  
Ground Motion ◽  
Earthquake Ground Motion ◽  
Dense Array ◽  
Rotational Components

scholarly journals Effect of Earthquake Ground Motion Duration on the Seismic Response of a Low-Rise RC Building

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Martin O. Martineau ◽  
Alvaro F. Lopez ◽  
Juan C. Vielma
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Short Duration ◽  
Nonlinear Dynamic Analysis ◽  
Earthquake Ground Motion ◽  
Structural Elements ◽  
Intensity Measure ◽  
Earthquake Record ◽  
Rc Building ◽  
Strength And Stiffness

This paper investigates the effect of earthquake ground motion duration on the seismic response of a low-rise reinforced concrete shear wall building. Two sets of spectrally equivalent ground motion sets were determined to isolate the effect of duration from other earthquake record characteristics. A numerical model that accounts for P-delta effects and degradation of strength and stiffness of the structural elements was used. Detailed nonlinear dynamic analysis for both the design and collapse levels of shaking was performed, considering the spectral acceleration at the fundamental period of vibration with intensity measure and material strains as engineering demand parameters. The results showed that at the design level of shaking, slightly larger interstory drifts were obtained under the short-duration events. However, the maximum values for interstory drifts were small, and minor damage is expected in the structure. When both seismic record sets were incrementally scaled until collapse, a slight increase in the material strains was found under the short-duration seismic events. Overall, it is indicated that ground motion duration does not influence the seismic response of low-rise buildings with low deformation capacity.

Sign in / Sign up

Export Citation Format

Share Document