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Bridge Dynamics
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Bridge Dynamics

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Civil Engineering".

Deadline for manuscript submissions: closed (30 April 2020) | Viewed by 54155

Special Issue Editors

Prof. Dr. Maria Anna Polak

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Guest Editor
Department of Civil & Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
Interests: structures; mechanics and construction; nonlinear finite element analysis; shear in slabs; strengthening and rehabilitation; nondestructive testing techniques for structural evaluations; Steel and concrete structures; mechanics of reinforced concrete structure
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Joanna Maria Dulińska

E-Mail Website
Guest Editor
Institute of Structural Mechanics, Civil Engineering Faculty, Cracow University of Technology, Warszawska 24, 31-155 Krakow, Poland
Interests: structures; mechanics and construction; dynamic of structures; bridge dynamics; nonlinear finite element analysis; seismic assessment; spatial variability of earthquake ground motions
Special Issues, Collections and Topics in MDPI journals
Dr. Izabela Joanna Drygała

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Guest Editor
Faculty of Civil Engineering, Cracow University of Technology, Warszawska 24, 31-155 Krakow, Poland
Interests: structures; mechanics and construction; dynamic of structures; nonlinear finite element analysis; seismic performance of bridges and footbridges; human-induced vibrations of footbridges; structural health monitoring (SHM) systems
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The Bridge Dynamics Special Issue is dedicated to academic researchers and civil engineering specialists who want to present their work on theoretical and experimental methods of analysis for dynamic aspects of bridge structures.

In view of the significance of dynamic issues for the protection and operation, as well as feasibility, of bridge structures, this Special Issue aims to bring together authors who want to present their experiences in research, design, construction, and utilization of bridges, with the focus on dynamics.

Some of the problems considered for this Special Issue include, but are not limited to, the following: Experimental and theoretical investigation of dynamic characteristics of bridges and footbridges; seismic performance of bridges and footbridges; dynamic analysis of railway bridges subjected to high speed trains; human-induced vibrations of footbridges; aerodynamic stability of bridge structures; structural health monitoring (SHM) systems; integration and management of SHM data for bridges and footbridges.

Prof. Dr. Maria Anna Polak
Prof. Dr. Joanna Maria Dulińska
Dr. Izabela Joanna Drygała
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Structural health monitoring (SHM)
  • Seismic assessment of bridges
  • Aerodynamic assessment of bridges
  • Dynamic characteristics of bridges and footbridges
  • Human-induced vibrations of footbridges
  • Bridge dynamics

Published Papers (18 papers)

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Research

19 pages, 1171 KiB  
Article
Nonlinear Aeroelastic in-Plane Behavior of Suspension Bridges under Steady Wind Flow
by Simona Di Nino and Angelo Luongo
Appl. Sci. 2020, 10(5), 1689; https://doi.org/10.3390/app10051689 - 02 Mar 2020
Cited by 15 | Viewed by 2426
Abstract
The nonlinear aeroelastic behavior of suspension bridges, undergoing dynamical in-plain instability (galloping), is analyzed. A nonlinear continuous model of bridge is formulated, made of a visco-elastic beam and a parabolic cable, connected each other by axially rigid suspenders, continuously distributed. The structure is [...] Read more.
The nonlinear aeroelastic behavior of suspension bridges, undergoing dynamical in-plain instability (galloping), is analyzed. A nonlinear continuous model of bridge is formulated, made of a visco-elastic beam and a parabolic cable, connected each other by axially rigid suspenders, continuously distributed. The structure is loaded by a uniform wind flow which acts normally to the bridge plane. Both external and internal damping are accounted for the structure, according to the Kelvin-Voigt rheological model. The nonlinear aeroelastic effects are evaluated via the quasi-static theory, while structural nonlinearities are not taken into account. First, the free dynamics of the undamped bridge are addressed, and the natural modes determined. Then, the nonlinear equations ruling the dynamics of the aeroelastic system, close to the bifurcation point, are tackled by the Multiple Scale Method. This is directly applied to the partial differential equations, and provides the finite-dimensional bifurcation equations. From these latter, the limit-cycle amplitude and its stability are evaluated as function of the mean wind velocity. A case study of suspension bridge is analyzed. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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17 pages, 4543 KiB  
Article
Ground Reaction Forces Generated by Runners—Harmonic Analyses and Modelling
by Marek Pańtak
Appl. Sci. 2020, 10(5), 1575; https://doi.org/10.3390/app10051575 - 25 Feb 2020
Cited by 9 | Viewed by 2693
Abstract
Building structures carrying pedestrian traffic, e.g., footbridges, long-span floors and long cantilevered platforms projecting outwards from the walls (long balconies), can be susceptible to the dynamic influence of its users. One type of dynamic action that can occur on these structures is the [...] Read more.
Building structures carrying pedestrian traffic, e.g., footbridges, long-span floors and long cantilevered platforms projecting outwards from the walls (long balconies), can be susceptible to the dynamic influence of its users. One type of dynamic action that can occur on these structures is the dynamic action of people running. The main aim of this paper is to present the results of the harmonic analyses and mathematical models of two types of ground reaction forces (GRFs) generated by people applying different running techniques, i.e., forefoot- and heel-strike (rearfoot) running technique. The analyses of the GRFs were performed on the basis of the results of laboratory tests of running people and concern the vertical component of the ground reaction forces (VGRFs) generated by runners. The harmonic analyses were performed using Fourier transform. The results of the study show the main features and differences between forces generated by forefoot- and heel-strike runners. Data obtained for various running styles allowed the development of a load model proposal for the VGRFs generated by heel-strike runners. The results of the VGRF parameterization and the proposed new VGRF model allow the VGRFs generated by forefoot and heel-strike runners to be accurately estimated in the case of normal running pace (recreational running). The application of the presented results allows improvements to the accuracy of determining the dynamic response of structures induced by runners. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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19 pages, 10420 KiB  
Article
Characteristics of the Wind Environment above Bridge Deck near the Pylon Zone and Wind Barrier Arrangement Criteria
by Dalei Wang, Yiquan Zhang, Mengjin Sun and Airong Chen
Appl. Sci. 2020, 10(4), 1437; https://doi.org/10.3390/app10041437 - 20 Feb 2020
Cited by 11 | Viewed by 2549
Abstract
Due to the complex arrangement of structural components in the vicinity of bridge pylon zones, the wind environment above bridge decks is very complicated. A sudden change in wind speed exerts an adverse effect on vehicle control stability. In order to investigate the [...] Read more.
Due to the complex arrangement of structural components in the vicinity of bridge pylon zones, the wind environment above bridge decks is very complicated. A sudden change in wind speed exerts an adverse effect on vehicle control stability. In order to investigate the characteristics of the flow field in the vicinity of the bridge pylon, the wind environment near an inverted Y-shaped pylon is studied by experimental and numerical methods. From the flow visualization and the wind speed measurement in the wind tunnel and the numerical simulation created using Fluent software, specific patterns of the direction and magnitude of wind speed at a range of vehicle height above the bridge deck near the pylon zone were observed along the longitudinal direction. This distribution pattern of the wind environment can effectively guide the wind barrier arrangement near the bridge pylon zone. Combined with the two safety evaluation indicators proposed in this paper, the optimal arrangement scheme of wind barriers in the bridge pylon zone of Sutong Bridge is determined. This paper deepens the understanding of the wind environment near the pylon zone and proposes an evaluation method for the wind environment near the pylon zone, which can serve as the basis for wind barrier arrangement in similar research projects. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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16 pages, 6049 KiB  
Article
Steady-Suction-Based Flow Control of Flutter of Long-Span Bridge
by Jian Zhan, Hongfu Zhang, Zhiwen Liu, Huan Liu, Dabo Xin and Jinping Ou
Appl. Sci. 2020, 10(4), 1372; https://doi.org/10.3390/app10041372 - 18 Feb 2020
Cited by 5 | Viewed by 1836
Abstract
The present wind tunnel study focuses on the effects of the steady-suction-based flow control method on the flutter performance of a 2DOF bridge deck section model. The suction applied to the bridge model was released from slots located at the girder bottom. The [...] Read more.
The present wind tunnel study focuses on the effects of the steady-suction-based flow control method on the flutter performance of a 2DOF bridge deck section model. The suction applied to the bridge model was released from slots located at the girder bottom. The suction rates of all slots along the span were equal and constant. A series of test cases with different combinations of suction slot positions, suction intervals, and suction rates were studied in detail for the bridge deck model. The experimental results showed that the steady-suction-based flow control method could improve the flutter characteristics of the bridge deck with a maximal increase in the critical flutter speed of up to 10.5%. In addition, the flutter derivatives (FDs) of the bridge deck with or without control were compared to investigate the fundamental mechanisms of the steady-suction-based control method. According to the results, installing a suction control device helps to strengthen aerodynamic damping, which is the primary cause for enhanced flutter performance of bridge decks. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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18 pages, 3511 KiB  
Article
Assessment of the Lateral Vibration Serviceability Limit State of Slender Footbridges Including the Postlock-in Behaviour
by Rocío G. Cuevas, Javier F. Jiménez-Alonso, Francisco Martínez and Iván M. Díaz
Appl. Sci. 2020, 10(3), 967; https://doi.org/10.3390/app10030967 - 02 Feb 2020
Cited by 7 | Viewed by 3045
Abstract
The lateral vibration serviceability of slender footbridges has been the subject of many studies over the last few decades. However, in spite of the large amount of research, a common criterion has not been set yet. Although the human–structure interaction phenomenon is widely [...] Read more.
The lateral vibration serviceability of slender footbridges has been the subject of many studies over the last few decades. However, in spite of the large amount of research, a common criterion has not been set yet. Although the human–structure interaction phenomenon is widely accepted as the main cause of the sudden onset of high amplitudes of vibration, the current design recommendations do not include an expression for the auto-induced component of the pedestrian action and, as a consequence, it is not possible to evaluate the footbridge comfort once the lock-in effect has developed. Hence, the purpose of this paper is to propose a general formulation, which allows the analysis of the different load scenarios that the footbridge will experience during its overall life cycle. An important advantage over most current design guidelines is that the procedure permits the evaluation of the comfort level of the footbridge, even with crowd densities above the “critical number”, and thus takes informed decisions about the possible use of external devices to control the vibration response, depending on the probability of occurrence of the problem. The performance of the proposed method is successfully evaluated through numerical response simulations of two real footbridges, showing a good agreement with the experimental data. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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23 pages, 5883 KiB  
Article
Influence of Multiple-Support Excitation on Seismic Response of Reinforced Concrete Arch Bridges
by Marta Savor Novak, Damir Lazarevic, Josip Atalic and Mario Uros
Appl. Sci. 2020, 10(1), 17; https://doi.org/10.3390/app10010017 - 18 Dec 2019
Cited by 12 | Viewed by 3654
Abstract
Although post-earthquake observations identified spatial variation of ground motion (i.e., multiple-support excitation) as a frequent cause of the unfavorable response of long-span bridges, this phenomenon is often not taken into account in seismic design to simplify the calculation procedure. This study investigates the [...] Read more.
Although post-earthquake observations identified spatial variation of ground motion (i.e., multiple-support excitation) as a frequent cause of the unfavorable response of long-span bridges, this phenomenon is often not taken into account in seismic design to simplify the calculation procedure. This study investigates the influence of multiple-support excitation accounting for coherency loss and wave-passage effects on the seismic response of reinforced concrete deck arch bridges of long spans founded on rock sites. Parametric numerical study was conducted using the time-history method, the response spectrum method, and a simplified procedure according to the European seismic standards. Results showed that multiple-support excitation had a detrimental influence on response of almost all analyzed bridges regardless of considered arch span. Both considered spatial variation effects, acting separately or simultaneously, proved to be very important, with their relative significance depending on the response values and arch locations analyzed and seismic records used. Therefore, it is suggested that all spatially variable ground-motion effects are taken into account in seismic analysis of similar bridges. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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17 pages, 4601 KiB  
Article
A Study on a Mechanism of Lateral Pedestrian-Footbridge Interaction
by Zhou Chen, Siyuan Chen, Xijun Ye and Yunlai Zhou
Appl. Sci. 2019, 9(23), 5257; https://doi.org/10.3390/app9235257 - 03 Dec 2019
Cited by 5 | Viewed by 2150
Abstract
Based on the pedestrian lateral force hybrid Van der Pol/Rayleigh model, this study investigates the interaction dynamic model of a pedestrian-flexible footbridge lateral coupling system. A multi scale method is adopted to decouple the equation. The paper also studies the nonlinear dynamic response [...] Read more.
Based on the pedestrian lateral force hybrid Van der Pol/Rayleigh model, this study investigates the interaction dynamic model of a pedestrian-flexible footbridge lateral coupling system. A multi scale method is adopted to decouple the equation. The paper also studies the nonlinear dynamic response of the pedestrian-footbridge coupling system as well as the relationship between the lateral displacement of pedestrians and flexible footbridges, and the lateral interaction of the two variables. The results show that with the same frequency tuning parameters, when the mass ratio of pedestrians and footbridges is very small, the larger the mass ratio is, the larger the lateral response amplitude of pedestrians becomes. Conversely, when the mass ratio of pedestrians and footbridges is much larger, the larger the mass ratio is, the smaller the response amplitude becomes. When the natural frequency of a footbridge is larger, its Phase Angle becomes larger. As the lateral amplitude of pedestrians increases, the Phase Angle approaches zero. Moreover, regarding the variation of the Phase Angle between the interaction force and footbridge lateral vibration speed based on the lateral relative displacement of pedestrians, of which the variation range is (0, π ), as the pedestrians’ lateral amplitude increases, the Phase Angle approaches − π / 2 . The dynamic load coefficient varies linearly with the lateral amplitude of pedestrian vibrations. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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Graphical abstract

17 pages, 8215 KiB  
Article
A Field Investigation on Vortex-Induced Vibrations of Stay Cables in a Cable-Stayed Bridge
by Wen-Li Chen, Donglai Gao, Shujin Laima and Hui Li
Appl. Sci. 2019, 9(21), 4556; https://doi.org/10.3390/app9214556 - 27 Oct 2019
Cited by 28 | Viewed by 3275
Abstract
A field study was conducted to identify the vortex-induced vibrations (VIVs) of stay cables in a cable-stayed bridge. A full-scale health-monitoring system was established to observe the wind effects of the selected cables. The vibration amplitudes in the twenty selected stay cables were [...] Read more.
A field study was conducted to identify the vortex-induced vibrations (VIVs) of stay cables in a cable-stayed bridge. A full-scale health-monitoring system was established to observe the wind effects of the selected cables. The vibration amplitudes in the twenty selected stay cables were first studied. The results indicate that only cable CAC20 has large amplitudes with a multimode and high-frequency vibration in the investigated period. The correlation between the wind and cable vibration was subsequently investigated. The large vibration amplitudes are primarily located in the mean speed scope of 4 to 6 m/s, simultaneously close to the reduced velocity of five when the wind was almost perpendicular to the bridge axis and had a smaller turbulence intensity. Moreover, the relationship between the maximum vibration amplitude with the mean wind speed was fitted by a function that was validated by the measured data. Finally, an estimation method was presented to predict the participative vibration modes that would happen in the VIVs of the stay cables, according to the known wind and cable parameters. The measured cable vibrations were employed to validate this estimation method. The results indicate the estimated vibration modes are close to the measured vibration modes. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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16 pages, 3579 KiB  
Article
An Improved Second-Order Blind Identification (SOBI) Signal De-Noising Method for Dynamic Deflection Measurements of Bridges Using Ground-Based Synthetic Aperture Radar (GBSAR)
by Xianglei Liu, Hui Wang, Ming Huang and Wanxin Yang
Appl. Sci. 2019, 9(17), 3561; https://doi.org/10.3390/app9173561 - 30 Aug 2019
Cited by 5 | Viewed by 2536
Abstract
Ground-based synthetic aperture radar (GBSAR) technology has been widely used for bridge dynamic deflection measurements due to its advantages of non-contact measurements, high frequency, and high accuracy. To reduce the influence of noise in dynamic deflection measurements of bridges using GBSAR—especially for noise [...] Read more.
Ground-based synthetic aperture radar (GBSAR) technology has been widely used for bridge dynamic deflection measurements due to its advantages of non-contact measurements, high frequency, and high accuracy. To reduce the influence of noise in dynamic deflection measurements of bridges using GBSAR—especially for noise of the instantaneous vibrations of the instrument itself caused by passing vehicles—an improved second-order blind identification (SOBI) signal de-noising method is proposed to obtain the de-noised time-series displacement of bridges. First, the obtained time-series displacements of three adjacent monitoring points in the same time domain are selected as observation signals, and the second-order correlations among the three time-series displacements are removed using a whitening process. Second, a mixing matrix is calculated using the joint approximation diagonalization technique for covariance matrices and to further obtain three separate signal components. Finally, the three separate signal components are converted in the frequency domain using the fast Fourier transform (FFT) algorithm, and the noise signal components are identified using a spectrum analysis. A new, independent, separated signal component matrix is generated using a zeroing process for the noise signal components. This process is inversely reconstructed using a mixing matrix to recover the original amplitude of the de-noised time-series displacement of the middle monitoring point among three adjacent monitoring points. The results of both simulated and on-site experiments show that the improved SOBI method has a powerful signal de-noising ability. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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24 pages, 12716 KiB  
Article
Practical Design Method of Yielding Steel Dampers in Concrete Cable-Stayed Bridges
by Yan Xu, Zeng Zeng, Cunyu Cui and Shijie Zeng
Appl. Sci. 2019, 9(14), 2857; https://doi.org/10.3390/app9142857 - 17 Jul 2019
Cited by 6 | Viewed by 2922
Abstract
Restrained transversal tower/pier–girder connections of cable-stayed bridges may lead to high seismic demands for tower columns when subject to earthquake excitations; however, free transversal tower/pier–girder connections may cause large relative displacement. Using an energy dissipation system can effectively control the bending moment of [...] Read more.
Restrained transversal tower/pier–girder connections of cable-stayed bridges may lead to high seismic demands for tower columns when subject to earthquake excitations; however, free transversal tower/pier–girder connections may cause large relative displacement. Using an energy dissipation system can effectively control the bending moment of tower columns and the relative tower/pier-girder displacement simultaneously, but repeated time history analyses are needed to determine reasonable design parameters, such as yield strength. In order to improve design efficiency, a practical design method is demanded. Therefore, the influence of yielding strength at different locations is studied by using comprehensive and parametric time history analyses at first. The results indicate that yielding steel dampers can significantly reduce the bending moment at tower columns and the relative pier–girder displacement due to the system switch mechanism during the vibration. Meanwhile, the yielding steel damper shows its general effect on reducing relative displacement between all piers/tower columns and the main girder as well, with only a localized effect on controlling seismic induced forces. Furthermore, a practical design method is proposed for engineering practices to determine key parameters of the yielding steel damper. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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12 pages, 3132 KiB  
Article
Seismic Retrofit of Steel Truss Bridge Using Buckling Restrained Damper
by Purevdorj Sosorburam and Eiki Yamaguchi
Appl. Sci. 2019, 9(14), 2791; https://doi.org/10.3390/app9142791 - 11 Jul 2019
Cited by 7 | Viewed by 3675
Abstract
Buckling Restrained Bracings (BRBs) are widely used to improve the seismic behavior of buildings. They are employed for bridges as well, but their application in this respect is limited. BRBs can also be used as a function of the individual damper rather than [...] Read more.
Buckling Restrained Bracings (BRBs) are widely used to improve the seismic behavior of buildings. They are employed for bridges as well, but their application in this respect is limited. BRBs can also be used as a function of the individual damper rather than the structural component or the bracing, in which case the device may be called a Buckling Restrained Damper (BRD). Yet, such application has not been explored much. There are quite a few bridges designed according to the old design codes in Japan. Their seismic resistance may not be satisfactory for the current seismic design codes. Against this background, the behavior of a steel truss bridge under a large seismic load was investigated by nonlinear dynamic finite element analysis. Some members were indeed found to be damaged in the earthquake. Retrofitting is needed. To this end, the application of BRD was tried in the present study: a parametric study on the seismic behavior of the truss bridge with BRD was conducted by changing the length, the cross-sectional area, the location and the inclination of BRD. The effectiveness of BRD was then discussed based on the numerical results thus obtained. In all the analyses, ABAQUS was used. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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14 pages, 2343 KiB  
Article
Dynamic Response Analysis of a Simply Supported Double-Beam System under Successive Moving Loads
by Lizhong Jiang, Yuntai Zhang, Yulin Feng, Wangbao Zhou and Zhihua Tan
Appl. Sci. 2019, 9(10), 2162; https://doi.org/10.3390/app9102162 - 27 May 2019
Cited by 27 | Viewed by 3522
Abstract
The dynamic response of a simply supported double-beam system under moving loads was studied. First, in order to reduce the difficulty of solving the equation, a finite sin-Fourier transform was used to transform the infinite-degree-of-freedom double-beam system into a superimposed two-degrees-of-freedom system. Second, [...] Read more.
The dynamic response of a simply supported double-beam system under moving loads was studied. First, in order to reduce the difficulty of solving the equation, a finite sin-Fourier transform was used to transform the infinite-degree-of-freedom double-beam system into a superimposed two-degrees-of-freedom system. Second, Duhamel’s integral was used to obtain the analytical expression of Fourier amplitude spectrum function considering the initial conditions. Finally, based on finite sin-Fourier inverse transform, the analytical expression of dynamic response of a simply supported double-beam system under moving loads was deduced. The dynamic response under successive moving loads was calculated by the analytical method and the general FEM software ANSYS. The analysis results show that the analytical method calculation results are consistent with ANSYS’ calculation, thus validating the analytical calculation method. The simply supported double-beam system had multiple critical speeds, and the flexural rigidity significantly affected both peak vertical displacement and critical speed. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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19 pages, 1635 KiB  
Article
Modified Multi-Support Response Spectrum Analysis of Structures with Multiple Supports under Incoherent Ground Excitation
by Jiyang Shen, Rui Li, Jun Shi and Guangchun Zhou
Appl. Sci. 2019, 9(9), 1744; https://doi.org/10.3390/app9091744 - 26 Apr 2019
Cited by 6 | Viewed by 2709
Abstract
This study develops a modified multi-support response spectrum (MSRS) method, in order to efficiently and accurately calculate the response of multi-support structures under incoherent ground motions. The modified MSRS method adopts three ancillary processes, constructing structural displacement vectors or constructing infinite stiffness members [...] Read more.
This study develops a modified multi-support response spectrum (MSRS) method, in order to efficiently and accurately calculate the response of multi-support structures under incoherent ground motions. The modified MSRS method adopts three ancillary processes, constructing structural displacement vectors or constructing infinite stiffness members or increasing the degrees of freedom at structural supports. Then, the modified MSRS method is verified in a comparison with the existing MSRS method through a model of a five-span reinforced concrete continuous rigid frame bridge. Finally, the collective structural response spectrum, the structural power spectrum, and the simplified structural power spectrum are deduced from the equation of the motion taking ground motion displacements as the input, and validated through the same bridge model. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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23 pages, 5834 KiB  
Article
Effect of Cyclic Load Amplitude on the Evolving Characteristics of Accumulative Deformation in Subgrade Bed
by Gang Liu, Mingzhi Zhao, Qiang Luo and Hongyu Jia
Appl. Sci. 2019, 9(7), 1435; https://doi.org/10.3390/app9071435 - 05 Apr 2019
Cited by 2 | Viewed by 2571
Abstract
To investigate the evolving characteristics of plastic deformation for the angular gravels that are used to construct subgrade bed, a laboratory model test is performed with cyclic load applying. Vertical deformation is measured in real time by displacement transducers and further modified to [...] Read more.
To investigate the evolving characteristics of plastic deformation for the angular gravels that are used to construct subgrade bed, a laboratory model test is performed with cyclic load applying. Vertical deformation is measured in real time by displacement transducers and further modified to analyze the plastic behavior of model fillings. It can be found that vertical plastic deformation shows quite different developing patterns under the effect of different cyclic amplitudes for a given model. A power function is adopted to describe the relationship between deformation rate and loading times. By analyzing the value of the power exponent and the corresponding developing features of plastic deformation rate, model filling status can be classified into four different zones, i.e., rapid stabilization, tardy stabilization, tardy failure, and rapid failure. Such a classification reveals different developing patterns of plastic deformation and satisfies the design of subgrade bed for ballasted and unballasted railway. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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17 pages, 4280 KiB  
Article
Effect of Vinyl Flooring on the Modal Properties of a Steel Footbridge
by Javier Fernando Jiménez-Alonso, Jorge Pérez-Aracil, Alejandro Mateo Hernández Díaz and Andrés Sáez
Appl. Sci. 2019, 9(7), 1374; https://doi.org/10.3390/app9071374 - 01 Apr 2019
Cited by 6 | Viewed by 3108
Abstract
Damping ratios associated with non-structural elements play an important role in mitigating the pedestrian-induced vibrations of slender footbridges. In particular, this paper analyses the effect of vinyl flooring on the modal parameters of steel footbridges. Motivated by the unexpected high experimental damping ratios [...] Read more.
Damping ratios associated with non-structural elements play an important role in mitigating the pedestrian-induced vibrations of slender footbridges. In particular, this paper analyses the effect of vinyl flooring on the modal parameters of steel footbridges. Motivated by the unexpected high experimental damping ratios of the first vibration modes of a real footbridge, whose deck was covered by a vinyl flooring, this paper aims at assessing more accurately the experimental damping ratios generated by this non-structural element on steel footbridges. For this purpose, a laboratory footbridge was built and vinyl flooring was installed on it. Its numerical and experimental modal parameters without and with the vinyl flooring were determined. The operational modal analysis method was used to estimate experimentally the modal parameters of the structure. The damping ratios associated with the vinyl flooring were obtained via the substraction between the experimental damping ratios of the laboratory footbridge with and without the vinyl flooring. An average increase of the damping ratios of 2.069% was observed due to the vinyl flooring installed. According to this result, this type of pavement may be a useful tool to significantly increase the damping ratios of steel footbridges in order to reduce pedestrian-induced vibrations. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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21 pages, 6824 KiB  
Article
Nonlinear and Non-Stationary Detection for Measured Dynamic Signal from Bridge Structure Based on Adaptive Decomposition and Multiscale Recurrence Analysis
by Erhua Zhang, Deshan Shan and Qiao Li
Appl. Sci. 2019, 9(7), 1302; https://doi.org/10.3390/app9071302 - 28 Mar 2019
Cited by 10 | Viewed by 3666
Abstract
To test the nonlinearity and non-stationarity of measured dynamic signals from a bridge structure with high-level noise and dense modal characteristics, a method that combines the adaptive signal decomposition with the recurrence analysis is proposed to solve the difficulty of testing nonlinearity and [...] Read more.
To test the nonlinearity and non-stationarity of measured dynamic signals from a bridge structure with high-level noise and dense modal characteristics, a method that combines the adaptive signal decomposition with the recurrence analysis is proposed to solve the difficulty of testing nonlinearity and non-stationarity of bridge structure signals. A novel white noise assistance and cluster analysis are introduced to the ensemble empirical mode decomposition to alleviate mode-mixing issues and generate single-mode intrinsic mode functions. Combining the hypothesis-testing scheme of nonstationary and nonlinear synchronization and surrogate techniques, a data-driven recurrence quantification analysis method is proposed and a novel recurrence quantification measure pairs are set up. To demonstrate the efficacy of the proposed methodology, complex signals, which are collected from a carefully instrumented model of a cable-stayed bridge, are utilized as the basis for comparing with traditional nonlinear and non-stationary test methods. Results show that the proposed multiscale recurrence method is feasible and effective for applications to a nonlinear and non-stationary test for real complex civil structures. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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16 pages, 5638 KiB  
Article
Dynamic Parameter Identification of a Long-Span Arch Bridge Based on GNSS-RTK Combined with CEEMDAN-WP Analysis
by Chunbao Xiong, Lina Yu and Yanbo Niu
Appl. Sci. 2019, 9(7), 1301; https://doi.org/10.3390/app9071301 - 28 Mar 2019
Cited by 8 | Viewed by 2858
Abstract
Under the action of wind, traffic, and other influences, long-span bridges are prone to large deformation, resulting in instability and even destruction. To investigate the dynamic characteristics of a long-span concrete-filled steel tubular arch bridge, we chose a global navigation satellite systems-real-time kinematic [...] Read more.
Under the action of wind, traffic, and other influences, long-span bridges are prone to large deformation, resulting in instability and even destruction. To investigate the dynamic characteristics of a long-span concrete-filled steel tubular arch bridge, we chose a global navigation satellite systems-real-time kinematic (GNSS-RTK) to monitor its vibration responses under ambient excitation. A novel approach, the use of complete ensemble empirical mode decomposition with adaptive noise combined with wavelet packet (CEEMDAN-WP) is proposed in this study to increase the accuracy of the signal collected by GNSS-RTK. Fast Fourier transform (FFT) and random decrement technique (RDT) were adopted to calculate structural modal parameters. To verify the combined denoising and modal parameter identification methods proposed in this paper, we established the structural finite element model (FEM) for comparison. Through simulation and comparison, we were able to draw the following conclusions. (1) GNSS-RTK can be used to monitor the dynamic response of long-span bridges under ambient excitation; (2) the CEEMDAN-WP is an efficient method used for the noise reduction of GNSS-RTK signals; (3) after signal filtering and noise reduction, structural modal parameters are successfully derived through RDT and illustrated graphically; and (4) the first-order natural frequency identified by field measurement is slightly higher than the FEM in this work, which may have been caused by bridge damage or the inadequate accuracy of the finite element model. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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24 pages, 6962 KiB  
Article
Dynamics of Double-Beam System with Various Symmetric Boundary Conditions Traversed by a Moving Force: Analytical Analyses
by Jing Yang, Xuhui He, Haiquan Jing, Hanfeng Wang and Sévérin Tinmitonde
Appl. Sci. 2019, 9(6), 1218; https://doi.org/10.3390/app9061218 - 22 Mar 2019
Cited by 5 | Viewed by 3575
Abstract
Dynamics of the double-beam system under moving loads have been paid much attention due to its wide applications in reality from the analytical point of view but the previous studies are limited to the simply supported boundary condition. In this study, to understand [...] Read more.
Dynamics of the double-beam system under moving loads have been paid much attention due to its wide applications in reality from the analytical point of view but the previous studies are limited to the simply supported boundary condition. In this study, to understand the vibration mechanism of the system with various boundary conditions, the double-beam system consisted of two general beams with a variety of symmetric boundary conditions (fixed-fixed, pinned-pinned, fixed-pinned, pinned-fixed and fixed-free) under the action of a moving force is studied analytically. The closed-form frequencies and mode shapes of the system with various symmetric boundary conditions are presented by the Bernoulli-Fourier method and validated with Finite Element results. The analytical explicit solutions are derived by the Modal Superposition method, which are verified with numerical results and previous results in the literature. As found, each wavenumber of the double-beam system is corresponding to two sub-modes of the system and the two sub-modes associated with the first wavenumber of the system both contribute significantly to the vibration of the system under a moving force. The analytical solutions indicate that the mass ratio, the bending stiffness ratio, the stiffness ratio of contact springs and the speed ratio of the moving force are the factors influencing the vibrations of the system under a moving force. The relationships between these dimensionless parameters and the displacement ratio of the system are investigated and presented in the form of plots, which could be referred in the design of the double-beam system. Full article
(This article belongs to the Special Issue Bridge Dynamics)
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