scholarly journals Dynamic performance of existing double track railway bridges at resonance with the increase of the operational line speed

2017 ◽  
Vol 132 ◽  
pp. 98-109 ◽  
Author(s):  
E. Moliner ◽  
M.D. Martínez-Rodrigo ◽  
P. Museros
Keyword(s):  
Dynamic Performance ◽  
Railway Bridges ◽  
Line Speed ◽  
At Resonance ◽  
Double Track

Robust Output Only Health Monitoring of Steel Railway Bridges

2020 ◽  
pp. 24-41
Author(s):  
Ahmed Rageh ◽  
Daniel Linzell ◽  
Samantha Lopez ◽  
Saeed Eftekhar Azam
Keyword(s):  
Health Monitoring ◽  
Three Dimensional ◽  
Supervised Machine Learning ◽  
Damage Scenario ◽  
Railway Bridges ◽  
Bridge Span ◽  
Structural Responses ◽  
Girder Bridge ◽  
Output Only ◽  
Double Track

This chapter extends application of a framework proposed by the authors (73, 74) for automated damage detection using strain measurements to study feasibility of using sensors that can measure accelerations, tilts, and displacements. The study utilized three-dimensional (3D) finite element models of double track, riveted, steel truss span, and girder bridge span under routine train loads. The chapter also includes three instrumentation schemes for each bridge span (65) to investigate the applicability of the framework to other bridge systems and sensor networks. Connection damage was simulated by reducing rotational spring stiffness at member ends and various responses were extracted for each damage scenario. The methodology utilizes Supervised Machine Learning to automatically determine damage location (DL) and intensity (DI). Simulated experiments showed that DLs and DIs were detected accurately for both spans with various structural responses and using different instrumentation plans.

Controlling bridge vibrations using a viscoelastic waveguide absorber

2017 ◽  
Vol 232 (4) ◽  
pp. 1088-1102 ◽  
Author(s):  
Caiyou Zhao ◽  
Ping Wang
Keyword(s):  
Energy Consumption ◽  
Dynamic Performance ◽  
Railway Track ◽  
Favourable Effect ◽  
Railway Bridges ◽  
Vibration Absorption ◽  
Parameter Configuration ◽  
Bridge Vibrations ◽  
The Impact ◽  
Track Slab

The study aims to mitigate the impact of structure-borne noise from existing elevated railway bridges on residents living along the line. In the study, a viscoelastic waveguide absorber mounted on a track slab was proposed based on waveguide vibration absorption techniques by proceeding from the vibration transmitting path and using the track slab as the carrier. First, a dynamic model for the slab-mounted viscoelastic waveguide absorber was constructed, in which a vibration equation was derived and an energy consumption mechanism was obtained. Then, a Chinese railway track style II (CRTS II) ballastless track slab most widely used in Chinese elevated railways was modelled as the primary vibration system, on which an experimental modal analysis was performed. Additionally, a parameterized analysis was performed on the dynamic performance of the slab-mounted viscoelastic waveguide absorber based on the vibration absorption and energy consumption mechanism of the absorber to determine the optimum parameter configuration for the dissipater. Furthermore, the most suitable installation positions for the energy waveguide links were defined using a response surface method. Finally, a bridge vibration response control effectiveness under train loads was also investigated, and it indicated that the waveguide absorbers had a favourable effect in reducing the vibration and structure-borne noise from the elevated railway bridge.

DYNAMIC PERFORMANCES OF A RAILWAY BRIDGE UNDER MOVING TRAIN LOAD USING EXPERIMENTAL MODAL PARAMETERS

2010 ◽  
Vol 10 (01) ◽  
pp. 91-109 ◽  
Author(s):  
SUNG-IL KIM ◽  
NAM-SIK KIM
Keyword(s):  
Test Specimen ◽  
Damping Ratio ◽  
Dynamic Performance ◽  
Performance Estimation ◽  
Modal Testing ◽  
Modal Parameters ◽  
Vibration Exciter ◽  
Railway Bridge ◽  
Railway Bridges ◽  
Moving Train

In the design of railway bridges, it is necessary to be able to predict their dynamic behavior under a moving train load so as to avoid a resonance state from repetitive moving axle forces with uniform intervals. According to design trends, newly developed girder bridges weigh less and have longer spans. Since the dynamic interaction between bridge superstructures and passing trains is one of the critical issues concerning such railway bridges that are designed with greater flexibility, it is very important to evaluate the modal parameters of newly designed PSC girders before carrying out dynamic analyses. In this paper, a full scale incrementally prestressed 25-meter long concrete girder was fabricated as a test specimen and modal testing was performed at every prestressing stage in order to evaluate the modal parameters, including the natural frequency and the modal damping ratio. Young's modulus was also obtained from the global stiffness of the test specimen. During the modal testing, a digitally controlled vibration exciter and an impact hammer were applied in order to obtain precise frequency response functions, and the modal parameters were evaluated at various construction stages. With the availability of reliable properties from the modal experiments, dynamic performance estimation of a PSC girder railway bridge during the passage of a moving train can be carried out.

scholarly journals Application of viscoelastic dampers for reducing dynamic response of high-speed railway bridges

2020 ◽  
Vol 11 (2) ◽  
pp. 95-106
Author(s):  
Mohamed Tahiri ◽  
Abdellatif Khamlichi ◽  
Mohammed Bezzazi
Keyword(s):  
High Speed ◽  
Contact Point ◽  
Dynamic Performance ◽  
Orientation Angle ◽  
Concrete Bridges ◽  
Bottom Surface ◽  
Vertical Acceleration ◽  
High Speed Railway ◽  
Railway Bridges ◽  
Viscoelastic Dampers

AbstractDue to the extensive development of high-speed railway lines which are operating at increasing velocities, the dynamic performance of railway bridges has become an important issue of scientific research. The aim of this study is to investigate the possibility of reducing the vertical acceleration and displacement of pre-stressed reinforced concrete bridges beams by using passive nonlinear viscoelastic dampers to retrofit them. The proposed solution is based on connecting the dampers directly to the abutments and the bottom surface of the bridge deck with an eccentricity between the neutral axis of the bridge and the contact point of the viscoelastic dampers. First, the dampers are modeled through the concept of linearized fractional derivatives to obtain energetic equivalent linear viscoelastic dampers. Optimization of the configuration of these dampers was performed then as function of the orientation angle and the eccentricity. Considering two bridges having different length that were studied in the literature with other systems of damping, it was found that the best orientation angle of dampers is close to 60°. It was found also that, in order to satisfy Eurocode 1 requirements, the total equivalent damping coefficient for the actual damping system is less than half of that required for systems using auxiliary beam to fix dampers, which indicates higher efficiency of the proposed solution.

scholarly journals Influence of bridge-based designed TMD on running trains

2018 ◽  
Vol 25 (1) ◽  
pp. 182-193 ◽  
Author(s):  
Zhaowei Chen ◽  
Hui Fang ◽  
Zhaoling Han ◽  
Shizheng Sun
Keyword(s):  
Design Methodology ◽  
Dynamic Performance ◽  
Engineering Problem ◽  
Bridge Engineering ◽  
Bridge Structure ◽  
Railway Bridges ◽  
Earthquake Loads ◽  
Practical Engineering ◽  
Track Bridge ◽  
Bridge Vibrations

A tuned mass damper (TMD) is a widely used vibration reduction measure in bridge engineering, whose design is based on the modal property of bridge structure. As a consequence, bridge vibrations in certain frequencies are reduced, while vibrations in some other frequencies may be amplified according to the design methodology of the TMD. This paper systematically investigates the influence of these amplified frequencies on the dynamic performance of running trains subject to earthquake loads. Primarily, the design methodology of bridge-based designed TMD (BBD-TMD) is introduced. On this basis, a detailed train–track–bridge coupled dynamic model with attached BBD-TMD is established based on the multi-body dynamics theory and the finite element method. Finally, aiming at a practical engineering problem in China, the influence of BBD-TMD on running trains subject to earthquake loads is investigated. The results indicate that, for the bridge structure adopted in this study, the amplified frequency bands are similar to the natural frequencies of the car body in the train system. To design TMDs for railway bridges, the dynamic performance of running trains caused by these external installations should be seriously considered.

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