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Vibration mitigation of high-speed railway bridges: Application of fluid viscous dampers
KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.ORCID iD: 0000-0002-1284-3641
2017 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

At the moment of writing, an expansion of the Swedish railway network has started, by constructions of new lines for high-speed trains. The aim is to create a high-speed connection between the most populous cities in Sweden - Stockholm, Göteborg and Malmö, and the rest of Europe. Thereby, the likelihood of faster, longer and heavier foreign trains crossing the Swedish lines is increased. However, this could be problematic since the dynamic response in railway bridges and, consequently, the risk of resonance increases with increasing train speeds.

Bridges are usually designed based on contemporary conditions and future requirements are rarely considered, due to e.g. cost issues. Prospectively, the dynamic performance of existing bridges may become insufficient. Hence, the current expansion of the high-speed railway network results in an increased demand of innovative design solutions for new bridges and cost-efficient upgrading methods for existing lines.

The aim of the present thesis is to propose a vibration mitigation strategy suitable for new and existing high-speed railway bridges. The main focus is a retrofit method with fluid viscous dampers installed between the bridge superstructure and the supports, which is intended to reduce the vertical bridge deck acceleration below the European design code limits. Furthermore, the intention is to investigate the efficiency of such a system, as well as to identify and analyse the parameters and uncertainties which could influence its functionality.

In order to examine the applicability of the proposed retrofit, case studies, statistical screenings and sensitivity analyses are performed and analysed. Two different models, a single-degree-of-freedom system and a finite element model, are developed and compared. From the different models, it is possible to study the influence from the damper parameters, the variability of the material properties and different modelling aspects on the bridge response. After the installation of the fluid viscous dampers, it is found that the acceleration level of the bridge deck is significantly reduced, even below the design code requirements.

Abstract [sv]

I skrivande stund har en utbyggnad av det svenska järnvägsnätet initierats. Målet är att skapa en höghastighetsanslutning mellan de folkrikaste städerna i Sverige - Stockholm, Göteborg och Malmö, och vidare ut i Europa. Därmed ökar sannolikheten att snabbare, längre och tyngre utländska tåg korsar de svenska järnvägslinjerna. Dock kan detta bli problematiskt i och med att järnvägsbroars dynamiska respons och, följaktligen, risken för resonans ökar med ökad tåghastighet.

Broar dimensioneras ofta utifrån nuvarande förutsättningar och hänsyn tas sällan till framtida hållbarhetskrav, exempelvis p.g.a. kostnadsbesparingar. Ur ett framtidsperspektiv kan därför det dynamiska beteendet hos befintliga broar komma att bli otillräckligt. Utbyggnaden av höghastighetsnätverket ökar därmed behovet av innovativa konstruktionslösningar för nya broar och kostnadseffektiva uppgraderingsmetoder för befintliga sträckor.

Syftet med föreliggande avhandling är att föreslå en metod för att minska de vibrationsnivåer som kan uppstå i både nybyggda och befintliga järnvägsbroar för höghastighetståg. Huvudfokus är en eftermonteringsmetod med viskösa dämpare, som har installerats mellan brons överbyggnad och landfästen, för att minska brobanans vertikala acceleration under gällande europeiska dimensioneringskrav. Vidare avses att undersöka effektiveteten av ett sådant system, samt att identifiera och analysera de parametrar och osäkerheter som kan påverka dess funktionalitet.

Fall- och parameterstudier, samt statistiska metoder används och utvärderas för att undersöka tillämpbarheten av den föreslagna vibrationsdämpningsmetoden. Två olika modeller, ett enfrihetsgradssystem och en finit elementmodell, har skapats och jämförts. Utifrån dessa modeller kan påverkan av dämparens parametrar, variabiliteten hos materialegenskaperna och behandlingen av olika modelleringsaspekter studeras. Från resultaten är det tydligt att brobanans accelerationsnivå avsevärt reduceras efter monteringen av viskösa dämpare, till och med under dimensioneringskraven.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2017. , 57 p.
Series
TRITA-BKN. Bulletin, ISSN 1103-4270 ; 147
Keyword [en]
dynamics, vibration mitigation, railway bridge, high-speed trains, bridge deck acceleration, passive damping, fluid viscous dampers, retrofit
Keyword [sv]
dynamik, vibrationsdämpning, järnvägsbro, höghastighetståg, brobaneacceleration, passiv dämpning, viskösa dämpare, eftermontering
National Category
Infrastructure Engineering
Research subject
Civil and Architectural Engineering
Identifiers
URN: urn:nbn:se:kth:diva-205672ISBN: 978-91-7729-383-5 (print)OAI: oai:DiVA.org:kth-205672DiVA: diva2:1090042
Presentation
2017-05-17, M108, Brinellvägen 23, Stockholm, 13:00 (English)
Opponent
Supervisors
Funder
Swedish Research Council Formas, 2010-1084
Note

QC 20170425

Available from: 2017-04-25 Created: 2017-04-21 Last updated: 2017-04-25Bibliographically approved
List of papers
1. Structural control of high-speed railway bridges by means of fluid viscous dampers
Open this publication in new window or tab >>Structural control of high-speed railway bridges by means of fluid viscous dampers
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2016 (English)In: 19th IABSE Congress 2016, Zürich, Switzerland, 2016, 2535-2542 p.Conference paper, Published paper (Other academic)
Abstract [en]

The dynamic response of structures is an important aspect to consider, especially at resonance. Particularly, bridges traversed by trains are at risk, due to the repeated loading with regular interval from the axle and bogie spacings. If the risk of resonance is not accounted for in the design, the vertical acceleration of the bridge deck may exceed the allowed limits of comfort and safety. Hence, alternative, sustainable measures for reducing the vibrations in bridges are required to solve these challenges. This paper presents studies of fluid viscous dampers used to control the dynamic behaviour of high-speed railway bridges. A finite element model is used to investigate the response of an existing bridge, both prior to and after the installation of dampers, and the influence of some parameters on the efficiency of the dampers are analysed. The results from this paper show that the vertical deck acceleration is sufficiently reduced using the proposed solution.

Place, publisher, year, edition, pages
Zürich, Switzerland: , 2016
Keyword
resonance, dynamic response, vibrations, bridges, high-speed trains, damper retrofit
National Category
Other Civil Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-205648 (URN)978-3-85748-144-4 (ISBN)
Conference
19th IABSE Congress on Challenges in Design and Construction of an Innovative and Sustainable Built Environment
Funder
Swedish Research Council Formas, 2010-1084
Note

QC 20170425

Available from: 2017-04-21 Created: 2017-04-21 Last updated: 2017-04-25Bibliographically approved
2. Application of fluid viscous dampers to mitigate vibrations of high-speed railway bridges
Open this publication in new window or tab >>Application of fluid viscous dampers to mitigate vibrations of high-speed railway bridges
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2017 (English)In: International Journal of Rail transportation, ISSN 2324-8378, E-ISSN 2324-8386, Vol. 5, no 1, 47-62 p.Article in journal (Refereed) Published
Abstract [en]

Several bridges along the Bothnia railway line in Sweden do not fulfil the Eurocode requirements regarding the maximum vertical bridge deck acceleration. The aim of this study is to investigate the possibility of reducing the acceleration of one of these bridges to an acceptable level by using post-installed viscous dampers. The bridge-damper system is described by a single-degree-of-freedom model. Assuming that the dampers do not change the mode shapes of the bridge, the model is further generalized to include higher order bending modes. The dampers are connected between the bottom surface of the bridge deck and the abutments.This creates an eccentricity between the connection point of the dampers and the neutral axis of the bridge, which is found to have a significant influence on the efficiency of the dampers. The results of this study also indicate that the proposed retrofit method can reduce the accelerations to an acceptable level.

Place, publisher, year, edition, pages
Abingdon, United Kingdom: Taylor & Francis Group, 2017
Keyword
Structural dynamics; railway bridges; high-speed trains; resonance; passive damping; fluid viscous dampers
National Category
Infrastructure Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-205653 (URN)10.1080/23248378.2016.1209444 (DOI)000396621000004 ()2-s2.0-8497848526 (Scopus ID)
Funder
Swedish Research Council Formas, 2010-1084
Note

QC 20170425

Available from: 2017-04-21 Created: 2017-04-21 Last updated: 2017-04-25Bibliographically approved
3. Sensitivity analysis of a high-speed railway bridge with supplemental fluid viscous dampers
Open this publication in new window or tab >>Sensitivity analysis of a high-speed railway bridge with supplemental fluid viscous dampers
(English)Manuscript (preprint) (Other academic)
Abstract [en]

One approach for upgrading existing high-speed bridges which are susceptible to excessive vibrations is to install damping devices. In this paper, a single-degree-of-freedom model of a simply-supported bridge with supplemental fluid viscous dampers installed between the superstructure and the abutments is derived based on an arbitrary mode of vibration. Further, to ensure the robustness of the proposed vibration mitigation method, a statistical screening of the uncertainties associated with the bridge-damper system is conducted using Monte-Carlo simulations. From this screening, it is possible to evaluate the probability of exceedance of a stipulated acceleration level, as well as studying the sensitivity of the ingoing random variables. This paper also highlights the necessity of conducting a statistical assessment to determine an estimate for the distribution of the acceleration limit and model uncertainty for dynamic analyses. The results also show that 1) the modulus of elasticity and structural damping should be treated as stochastic variables for the studied bridge, 2) it is sufficient to install damping devices only at the moveable bearing and 3) the proposed retrofit is insufficient if the friction of the moveable bearings is not overcome for the given set of damper parameters.

Keyword
Structural dynamics, high-speed railway bridge, fluid viscous damper, statistical screening, sensitivity analysis
National Category
Infrastructure Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-205659 (URN)
Funder
Swedish Research Council Formas, 2010-1084
Note

QC 20170425

Available from: 2017-04-21 Created: 2017-04-21 Last updated: 2017-04-25Bibliographically approved

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