• Title/Summary/Keyword: cable vibration

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Improvement of the Performance Based Seismic Design Method of Cable Supported Bridges with Resilient-Friction Base Isolation Systems (II-Proposal for the Seismic Design Procedure) (마찰복원형 지진격리장치가 설치된 케이블교량의 성능 기반 내진설계법 개선(II-내진설계 절차 제안))

  • Gil, Heungbae;Park, Sun Kyu;Han, Kyoung Bong;Yoon, Wan Seok
    • Journal of the Earthquake Engineering Society of Korea
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    • v.24 no.4
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    • pp.169-178
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    • 2020

  • In a previous paper, ambient vibration tests were conducted on a cable stayed bridge with resilient-friction base isolation systems (R-FBI) to extract the dynamic characteristics of the bridge and compare the results with a seismic analysis model. In this paper, a nonlinear seismic analysis model was established for analysis of the bridge to compare the difference in seismic responses between nonlinear time history analysis and multi-mode spectral analysis methods in the seismic design phase of cable supported bridges. Through these studies, it was confirmed that the seismic design procedures of the "Korean Highway Bridge Design Code (Limit State Design) for Cable Supported Bridges" is not suitable for cable supported bridges installed with R-FBI. Therefore, to reflect the actual dynamic characteristics of the R-FBI installed on cable-supported bridges, an improved seismic design procedure is proposed that applies the seismic analysis method differently depending on the seismic isolation effect of the R-FBI for each seismic performance level.

  • https://doi.org/10.5000/EESK.2020.24.4.169 인용 PDF KSCI

Numerical framework for stress cycle assessment of cables under vortex shedding excitations

  • Ruiz, Rafael O.;Loyola, Luis;Beltran, Juan F.
    • Wind and Structures
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    • v.28 no.4
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    • pp.225-238
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    • 2019

  • In this paper a novel and efficient computational framework to estimate the stress range versus number of cycles curves experienced by a cable due to external excitations (e.g., seismic excitations, traffic and wind-induced vibrations, among others) is proposed. This study is limited to the wind-cable interaction governed by the Vortex Shedding mechanism which mainly rules cables vibrations at low amplitudes that may lead to their failure due to bending fatigue damage. The algorithm relies on a stochastic approach to account for the uncertainties in the cable properties, initial conditions, damping, and wind excitation which are the variables that govern the wind-induced vibration phenomena in cables. These uncertainties are propagated adopting Monte Carlo simulations and the concept of importance sampling, which is used to reduce significantly the computational costs when new scenarios with different probabilistic models for the uncertainties are evaluated. A high fidelity cable model is also proposed, capturing the effect of its internal wires distribution and helix angles on the cables stress. Simulation results on a 15 mm diameter high-strength steel strand reveal that not accounting for the initial conditions uncertainties or using a coarse wind speed discretization lead to an underestimation of the stress range experienced by the cable. In addition, parametric studies illustrate the computational efficiency of the algorithm at estimating new scenarios with new probabilistic models, running 3000 times faster than the base case.

  • https://doi.org/10.12989/was.2019.28.4.225 인용 KSCI