Influence of cable vibration on seismic response of cable-stayed bridges

1995 ◽  
Vol 22 (5) ◽  
pp. 1001-1020 ◽  
Author(s):  
Raju Tuladhar ◽  
Walter H. Dilger ◽  
Mamdouh M. Elbadry
Keyword(s):  
Seismic Response ◽  
Seismic Behaviour ◽  
Cable Vibration ◽  
Fundamental Frequencies ◽  
Parametric Studies ◽  
Modulus Method ◽  
Cable Vibrations ◽  
Equivalent Modulus ◽  
Response Modelling ◽  
Cable Stayed Bridges

In cable-stayed bridges, modelling the cables is of particular significance for the seismic behaviour of the structure. The common practice of modelling a cable by a single truss element is inadequate for seismic response calculations because it essentially precludes the lateral cable vibration modes. The present paper studies the influence of cable vibrations on the seismic response of cable-stayed bridges. Three bridge examples with different spans and properties were used. Cable vibrations are accounted for through the use of multiple links for each cable. Cable vibration effects are found to be significant for seismic response calculations, particularly when the cable fundamental frequencies are overlapping with the first few frequencies of the bridge. Parametric studies are conducted with regard to the number of links per cable, the effect of the modulus of elasticity of the cables, and different earthquakes on the bridge response. Modelling the cables by two links per cable such that at least the fundamental modes of the cable vibrations are represented can significantly account for the effect of cable vibrations. It is also observed that the equivalent modulus method cannot in any way account for the cable vibration effects. Key words: cable vibration, dynamic analysis, equivalent modulus, multiple links, seismic response, cable-stayed bridge.

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>

Mitigation of Wind-Rain-Induced Cable Vibration in Cable-Stayed Bridges: Measurement Error

2012 ◽  
Vol 226-228 ◽  
pp. 1630-1633
Author(s):  
Ling Yun Wang
Keyword(s):  
Measurement Error ◽  
Active Control ◽  
Control Method ◽  
Optical Tracking ◽  
Design Guideline ◽  
Cable Vibration ◽  
Long Span ◽  
Cable Vibrations ◽  
Active Control Method ◽  
Cable Stayed Bridges

Recent advances in structural and construction technologies have enabled engineers to use the cable efficiently in relatively large structures such as long span cable-stayed bridges. It appeared that many factors and phenomena can generate cable vibration. The cables usually possess low damping and are therefore prone to many vibration problems, even causing large displacement. The active control method has been introduced to control the cable vibration in the cable-stayed bridges. The active control method is an effective method to suppress cable vibrations by adjusting the cable tension which is varied with time. This approach utilizes the axial motion of cables supported by an actuator installed at the anchorage to produce a time-varying force in the cable. To synthesize the feedback control signal, the cable vibration is measured by an optical tracking sensor attached at the mid-span cable. The studies are carried out to investigate the measurement error features of the control method as a design guideline.

The Influence of Support Hardware and Piping System Seismic Response on Snubber Support Damping

1997 ◽  
Vol 119 (4) ◽  
pp. 451-456 ◽  
Author(s):  
C. Lay ◽  
O. A. Abu-Yasein ◽  
M. A. Pickett ◽  
J. Madia ◽  
S. K. Sinha
Keyword(s):  
Seismic Response ◽  
Fundamental Frequency ◽  
Damping Ratio ◽  
Damping Coefficient ◽  
Piping System ◽  
Nodal Displacement ◽  
Damping Coefficients ◽  
Fundamental Frequencies ◽  
Piping Systems

The damping coefficients and ratios of piping system snubber supports were found to vary logarithmically with pipe support nodal displacement. For piping systems with fundamental frequencies in the range of 0.6 to 6.6 Hz, the support damping ratio for snubber supports was found to increase with increasing fundamental frequency. For 3-kip snubbers, damping coefficient and damping ratio decreased logarithmically with nodal displacement, indicating that the 3-kip snubbers studied behaved essentially as coulomb dampers; while for the 10-kip snubbers studied, damping coefficient and damping ratio increased logarithmically with nodal displacement.

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.

Sign in / Sign up

Export Citation Format

Share Document