scholarly journals PARAMETRIC STUDY ON STEEL TOWER SEISMIC RESPONSE OF CABLE-STAYED BRIDGES UNDER GREAT EARTHQUAKE GROUND MOTION

2003 ◽  
Vol 20 (1) ◽  
pp. 25S-41S ◽  
Author(s):  
Shehata E. ABDEL RAHEEM ◽  
Toshiro HAYASHIKAWA
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Parametric Study ◽  
Great Earthquake ◽  
Earthquake Ground Motion ◽  
Cable Stayed Bridges

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.

scholarly journals Multi-angle and nonuniform ground motions on cable-stayed bridges

2021 ◽  
pp. 875529302110513
Author(s):  
Eleftheria Efthymiou ◽  
Alfredo Camara
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Seismic Waves ◽  
Incidence Angle ◽  
Design Parameters ◽  
System Configuration ◽  
Cable System ◽  
Parametric Problem ◽  
Wide Range ◽  
Cable Stayed Bridges

The definition of the spatial variability of the ground motion (SVGM) is a complex and multi-parametric problem. Its effect on the seismic response of cable-stayed bridges is important, yet not entirely understood to date. This work examines the effect of the SVGM on the seismic response of cable-stayed bridges by means of the time delay of the ground motion at different supports, the loss of coherency of the seismic waves, and the incidence angle of the seismic waves. The focus herein is the effect of the SVGM on cable-stayed bridges with various configurations in terms of their length and of design parameters such as the pylon shape and the pylon–cable system configuration. The aim of this article is to provide general conclusions that are applicable to a wide range of canonical cable-stayed bridges and to contribute to the ongoing effort to interpret and predict the effect of the SVGM in long structures. This work shows that the effect of the SVGM on the seismic response of cable-stayed bridges varies depending on the pylon shape, height, and section dimensions; on the cable-system configuration; and on the response quantity of interest. Furthermore, the earthquake incidence angle defines whether the SVGM is important to the seismic response of the cable-stayed bridges. It is also confirmed that the SVGM excites vibration modes of the bridges that do not contribute to their seismic response when identical support motion is considered.

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.

Influence of near-fault ground motion characteristics on the seismic response of cable-stayed bridges

2020 ◽  
Vol 18 (14) ◽  
pp. 6375-6403
Author(s):  
Chao Zhang ◽  
Jian-bing Lu ◽  
Hong-yu Jia ◽  
Zhi-chao Lai ◽  
Xu Li ◽  
...  
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Near Fault ◽  
Motion Characteristics ◽  
Near Fault Ground Motion ◽  
Cable Stayed Bridges

Ground motion spatial variability and cable-stayed bridges: do we need to consider the asynchronous motion?

2021 ◽  
Author(s):  
Eleftheria Efthymiou ◽  
Alfredo Camara
Keyword(s):  
Spatial Variability ◽  
Seismic Response ◽  
Ground Motion ◽  
Structural Integrity ◽  
Seismic Behaviour ◽  
Long Span ◽  
Seismic Fault ◽  
Differential Movement ◽  
Extensive Program ◽  
Cable Stayed Bridges

<p>Cable-stayed bridges are landmark structures and key parts of transportation networks worldwide. It is of vital importance that their integrity is ensured even under very large earthquakes. The spatial variability of the ground motion could be a significant aspect of the seismic behaviour of long-span cable-stayed bridges due to the differential movement of the pylons, which may lead to an amplified seismic response and increased damage in the pylons. The purpose of this paper is to examine the effect of the spatial variability of the ground motion on the seismic response of cable-stayed bridges with H-shaped pylons and various span lengths. Focus is placed on the pylons of the bridges because the constitute key members for the overall stability and structural integrity of the bridge. The study explores how important the spatial variability is in the seismic response of cable-stayed bridges by considering two different orientations of the structures with respect to the seismic fault in an extensive program of non-linear response-history analyses.</p>

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