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Arvidsson, T., Andersson, A. & Karoumi, R. (2019). Train running safety on non-ballasted bridges. International Journal of Rail transportation, 7(1), 1-22
Open this publication in new window or tab >>Train running safety on non-ballasted bridges
2019 (English)In: International Journal of Rail transportation, ISSN 2324-8378, E-ISSN 2324-8386, Vol. 7, no 1, p. 1-22Article in journal (Refereed) Published
Abstract [en]

The train running safety on non-ballasted bridges is studied based on safety indices from the vertical wheel-rail forces. A 2D train- track-bridge interaction model that allows for wheel-rail contact loss is adopted for a comprehensive parametric study on high-speed passenger trains. The relation between bridge response and vehicle response is studied for more than 200 theoretical bridges in 1-3 spans. The bridge's influence on running safety and passenger comfort is differentiated from the influence of the track irregularities. The Eurocode bridge deck acceleration limit for non-ballasted bridges is 5 m/s(2) based on the assumed derailment risk at 1 g from wheel-rail contact loss. This study shows that the running safety indices are not compromised for bridge accelerations up to 30 m/s(2). Thus, accelerations at 1 g do not in itself lead to contact loss and there is potential to enhance the Eurocode safety limits for non-ballasted bridges.

Place, publisher, year, edition, pages
Taylor & Francis, 2019
Keywords
Railway bridge, slab track, deck acceleration, train-track-bridge interaction, wheel-rail force, running safety
National Category
Infrastructure Engineering
Identifiers
urn:nbn:se:kth:diva-254133 (URN)10.1080/23248378.2018.1503975 (DOI)000469852200001 ()2-s2.0-85052582924 (Scopus ID)
Note

QC 20190620

Available from: 2019-06-20 Created: 2019-06-20 Last updated: 2019-06-20Bibliographically approved
Andersson, A., Lind Östlund, J., Mahir, Ü.-K., Battini, J.-M. & Karoumi, R. (2018). Full-Scale Dynamic Testing of a Railway Bridge Using a Hydraulic Exciter. In: Conte, JP Astroza, R Benzoni, G Feltrin, G Loh, KJ Moaveni, B (Ed.), EXPERIMENTAL VIBRATION ANALYSIS FOR CIVIL STRUCTURES: TESTING, SENSING, MONITORING, AND CONTROL. Paper presented at International Conference on Experimental Vibration Analysis for Civil Engineering Structures (EVACES), JUL 12-14, 2017, Univ California San Diego, San Diego, CA (pp. 354-363). SPRINGER INTERNATIONAL PUBLISHING AG
Open this publication in new window or tab >>Full-Scale Dynamic Testing of a Railway Bridge Using a Hydraulic Exciter
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2018 (English)In: EXPERIMENTAL VIBRATION ANALYSIS FOR CIVIL STRUCTURES: TESTING, SENSING, MONITORING, AND CONTROL / [ed] Conte, JP Astroza, R Benzoni, G Feltrin, G Loh, KJ Moaveni, B, SPRINGER INTERNATIONAL PUBLISHING AG , 2018, p. 354-363Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents a full-scale dynamic testing on a simply supported railway bridge with integrated end-shields, by using a hydraulic exciter. Experimental frequency response functions are determined based on load controlled frequency sweeps. Apart from accurate estimates of natural frequencies, damping and mode shapes, the experimental testing also gives valuable information about the dynamic characteristics at resonance and amplitude dependent nonlinearities. Numerical models are used to simulate the dynamic response from passing trains which is compared to experimental testing of similar train passages. The results show that the bridge deck is partially constrained due to the interaction between the end-shields and the wing walls with the surrounding soil. Measurements at the supports also show that the flexibility of the foundation needs to be accounted for. An updated numerical model is able to accurately predict the response from passing trains. The response is lower than that predicted from the initial simulations and the bridge will fulfil the design requirements regarding vertical deck acceleration.

Place, publisher, year, edition, pages
SPRINGER INTERNATIONAL PUBLISHING AG, 2018
Series
Lecture Notes in Civil Engineering, ISSN 2366-2557 ; 5
Keywords
Railway bridge, Dynamics, Full-scale test, Hydraulic exciter, Frequency response function
National Category
Infrastructure Engineering
Identifiers
urn:nbn:se:kth:diva-242273 (URN)10.1007/978-3-319-67443-8_30 (DOI)000455235800030 ()2-s2.0-85060189447 (Scopus ID)978-3-319-67443-8 (ISBN)978-3-319-67442-1 (ISBN)
Conference
International Conference on Experimental Vibration Analysis for Civil Engineering Structures (EVACES), JUL 12-14, 2017, Univ California San Diego, San Diego, CA
Note

QC 20190201

Available from: 2019-02-01 Created: 2019-02-01 Last updated: 2019-02-01Bibliographically approved
Zangeneh, A., Svedholm, C., Andersson, A., Pacoste, C. & Karoumi, R. (2018). Identification of soil-structure interaction effect in a portal frame railway bridge through full-scale dynamic testing. Engineering structures, 159, 299-309
Open this publication in new window or tab >>Identification of soil-structure interaction effect in a portal frame railway bridge through full-scale dynamic testing
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2018 (English)In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 159, p. 299-309Article in journal (Refereed) Published
Abstract [en]

This paper is devoted to identify the effect of soil-structure interaction on the dynamic response of,a portal frame railway bridge. The study aims to validate the accuracy of numerical models in evaluating the dynamic stiffness and modal properties of the bridge-soil system. To achieve this aim, a controlled vibration test has been performed on a full-scale portal frame bridge to determine the modal properties of the system through measuring Frequency Response Functions. The results of the dynamic test provide reference data for FE model calibration as well as valuable information about the dynamic behavior of this type of bridges. Using the experimental data, an FRF-based model updating procedure was used to calibrate a full 3D solid model involving the entire bridge track-soil system. Both measured and computed responses identify the substantial contribution of the surrounding soil on the global damping of the system and highlight the importance of the soil-structure interaction on the dynamic response of this type of bridges. The identified modal damping ratio corresponding to the fundamental bending mode of the studied bridge was nearly 5 times higher than the recommended design values. A simplified model for the surrounding soil was also proposed in order to attain a less complicated model appropriate for practical design purposes.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2018
Keywords
Portal frame bridge, Full-scale dynamic test, Soil-structure interaction, Model updating, Frequency response functions
National Category
Civil Engineering
Identifiers
urn:nbn:se:kth:diva-223776 (URN)10.1016/j.engstruct.2018.01.014 (DOI)000425203000024 ()2-s2.0-85044636227 (Scopus ID)
Funder
Swedish Research Council FormasSwedish Transport Administration
Note

QC 20180307

Available from: 2018-03-07 Created: 2018-03-07 Last updated: 2018-03-15Bibliographically approved
Aggestam, E., Nielsen, J. C., Andersson, A. & Li, M. (2018). Multi-objective design optimisation of transition zones between different railway track forms. In: Proceedings of the 11th International Conference on Contact Mechanics and Wear of Rail/wheel Systems, CM 2018: . Paper presented at 11th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, CM 2018, Delft, Netherlands, 24 September 2018 through 27 September 2018 (pp. 1-6). TU Delft
Open this publication in new window or tab >>Multi-objective design optimisation of transition zones between different railway track forms
2018 (English)In: Proceedings of the 11th International Conference on Contact Mechanics and Wear of Rail/wheel Systems, CM 2018, TU Delft , 2018, p. 1-6Conference paper, Published paper (Refereed)
Abstract [en]

The vertical dynamic interaction between vehicle and railway track is simulated in the time domain using an extended state space vector approach. The track model includes a transition zone between slab track on a bridge and ballasted track on an embankment. By considering a multi-objective optimisation problem, solved using a genetic algorithm, selected vehicle and track responses are simultaneously minimised by optimising the distributions of rail pad stiffness and sleeper spacing in the transition zone. It is shown that the magnitudes of the maximum dynamic loads in the optimised transition zone can be reduced to be similar as the magnitudes far away from the transition zone.

Place, publisher, year, edition, pages
TU Delft, 2018
Keywords
Genetic algorithm., Optimisation, Railway track transitions, Slab track, Transition zone, Vehicle-track interaction
National Category
Vehicle Engineering
Identifiers
urn:nbn:se:kth:diva-241879 (URN)2-s2.0-85059534739 (Scopus ID)9789461869630 (ISBN)
Conference
11th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, CM 2018, Delft, Netherlands, 24 September 2018 through 27 September 2018
Note

QC 20190125

Available from: 2019-01-25 Created: 2019-01-25 Last updated: 2019-01-25Bibliographically approved
Andersson, A. (2018). Simplified approach to dynamic analysis of railway bridges for high-speed trains. Stockholm: KTH Royal Institute of Technology
Open this publication in new window or tab >>Simplified approach to dynamic analysis of railway bridges for high-speed trains
2018 (English)Report (Other academic)
Abstract [en]

In this report the analysis of 278 existing railway bridges is presented. The aim is to investigate how many of these bridges that potentially can be upgraded to higher speeds, with a target of 250 km/h. Due to the vast amount of bridges and the limited resources, the analyses are performed using simplified 2D models. The analysis is afflicted with several uncertainties, both regarding input parameters as well as model uncertainties. The results should therefore be interpreted carefully and primarily serve as an indicator for which bridges that may or may not meet the requirements. Large uncertainties are especially expected for portal frame bridges due to its inherently large interaction with the surrounding embankment and 3D behaviour.

The results from the analysis show that a total of 22 bridges theoretically fail to meet the dynamic requirements. A combination of refined analysis and experimental validation is recommended to better assess the dynamic response for these bridges. Among the most critical cases are several steel-concrete composite bridges, that due to a combination of low mass and low natural frequency may be prone to resonant loading. Retrofitting with external dampers may for some bridges be a viable solution.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2018. p. 312
Series
TRITA-ABE-RPT ; 1837
Keywords
Railway bridge; high-speed train; dynamic analysis; deck acceleration
National Category
Infrastructure Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-240578 (URN)KTH/BKN/RPT-1837-SE (ISRN)
Funder
Swedish Transport Administration, TRV 2018/109558
Note

QC 20181221

Available from: 2018-12-20 Created: 2018-12-20 Last updated: 2018-12-21Bibliographically approved
Arvidsson, T., Zangeneh, A., Cantero, D. & Andersson, A. (2017). Influence of Sleeper Passing Frequency on Short Span Bridges: Validation against Measured Results. In: : . Paper presented at First International Conference on Rail Transportation, Chengdu, China, July 10-12. , Article ID 299.
Open this publication in new window or tab >>Influence of Sleeper Passing Frequency on Short Span Bridges: Validation against Measured Results
2017 (English)Conference paper, Published paper (Refereed)
Abstract [en]

The railway track, being discretely supported at each sleeper, has a varying stiffness. The periodic loading from the wheels passing the sleepers at a certain speed introduces the sleeper passing frequency. This excitation of the track is a well-known source of vibration for track embankments. However, the interaction between the sleeper passing frequency and the railway bridge vibration is not well studied. In this paper, a 2D finite element model is calibrated against measured frequency response functions from a short span portal frame bridge. The track is modelled with the rail as a beam resting on discrete spring–dashpots at each sleeper location. In replicating the measured signals from train passages, the train load is typically idealized as moving forces. For the case study bridge, the resulting bridge deck acceleration amplitudes from such a moving force analysis were significantly lower compared to the measured signal. It is shown that if the wheel mass is introduced in the model, and thus the sleeper passing frequency, the model provides results in good agreement with measured data. Thus, it is demonstrated that the bridge deck vibration can be greatly amplified if the sleeper passing frequency matches a bridge frequency. A sensitivity analysis shows that the effect of the sleeper passing frequency is sensitive to track stiffness and bridge frequency.

National Category
Infrastructure Engineering
Identifiers
urn:nbn:se:kth:diva-221628 (URN)
Conference
First International Conference on Rail Transportation, Chengdu, China, July 10-12
Note

QCR 20180124

Available from: 2018-01-17 Created: 2018-01-17 Last updated: 2018-03-29Bibliographically approved
Lind Östlund, J., Andersson, A., Mahir, Ü.-K. & Battini, J.-M. (2017). Soil-Structure Interaction for foundations on High-Speed Railway Bridges. Stockholm: KTH Royal Institute of Technology
Open this publication in new window or tab >>Soil-Structure Interaction for foundations on High-Speed Railway Bridges
2017 (English)Report (Other academic)
Abstract [en]

This report contains a parametric study on the dynamic response of railway bridges on flexible supports. The results are based on simulations using 2D and 3D models. The dynamic stiffness of the supports is described by separate models of the foundation, including relevant stress and strain dependent soil properties from permanent loading that is linearized in a subsequent dynamic analysis. The complex-valued dynamic stiffness constitutes the boundary conditions in a separate analysis of the bridge superstructure that is solved in frequency domain.

Two different foundation types are studied; shallow slab foundation with relatively good ground conditions, and pile group foundations with relatively poor ground conditions. In both cases, the foundation slab and the pile group have fixed geometry. In the parametric study, the corresponding vertical static foundation stiffness range from 2 – 20 GN/m for the slab foundation and 5 – 25 GN/m for the pile group foundation.

For the slab foundations, both the stiffness and damping highly depends on the properties of the soil, foundation depth and geometry of the foundation slab. For the pile group foundations, the stiffness is mainly governed by the pile group and the damping by the soil.

Based on the simulations, the additional damping from the slab foundation is in most cases negligible. Only for relatively soft foundations and short-span bridges significant additional damping is seen. For the pile group foundations, the additional damping is in some cases significant, especially for deeper foundations and short-span bridges. Considering a lower bound of the parametric study does however result in a negligible contribution.

The dynamic response from passing trains show that the assumption of fixed supports in most cases is conservative. However, the flexible supports may result in a lower natural frequency that should be accounted for in order to not underestimate the resonance speed of the train.

If flexible supports are included in a dynamic analysis, both the stiffness and damping component needs to be included. The frequency-domain approach presented in this report is a viable solution technique but is not implemented in most commercial software used in the industry.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2017. p. 65
Series
TRITA-BKN, ISSN 1103-4289 ; 166
Keywords
Dynamic soil-structure interaction; impedance; foundation stiffness; railway bridge; high-speed trains
National Category
Infrastructure Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-230757 (URN)
Funder
Swedish Transport Administration, TRV 2016/56775
Note

QC 20180618

Available from: 2018-06-15 Created: 2018-06-15 Last updated: 2018-06-18Bibliographically approved
Andersson, A. & Arvidsson, T. (2017). Train-Track-Bridge Interaction for non-ballasted Railway Bridges on High-Speed Lines. Stockholm
Open this publication in new window or tab >>Train-Track-Bridge Interaction for non-ballasted Railway Bridges on High-Speed Lines
2017 (English)Report (Other academic)
Abstract [en]

This report contains a comprehensive parametric study on the coupled dynamic train–track–bridge interaction (TTBI) system for non-ballasted railway bridges. The existing design limits in Eurocode EN 1990 A2 regarding vertical deck acceleration and vertical deck displacement is compared with the wheel–rail forces and car body acceleration from simulations.

The simulations are based on a 2D TTBI model with linear Hertzian contact that allows for loss of contact. The model has been verified against both other numerical simulations as well as experiments, all with good agreement. The parametric study consists of a large number of theoretical bridges, all optimized to reach the limit of either vertical deck acceleration or vertical deck displacement. The study comprises both single- and double track bridges.

The track irregularities are found to be of paramount importance. Two different levels are therefore studied; “higher track quality” corresponding to a well-maintained track for high-speed railways and “lower track quality” corresponding to the Alert Limit in EN 13848-5. The final conclusions are based on the “lower track quality” in order not to underestimate the risk of running safety and passenger comfort. Simulations with the bridge excluded show that the additional contribution from the bridge is low, especially for the lower track quality.

The existing limit for vertical deck acceleration is set to 5 m/s2 in EN 1990 A2 and is based on a very simple assumption of the gravity acceleration reduced by a factor 2. The results in this report show that this likely is a too conservative measure of the running safety. Based on the wheel–rail forces from the simulations, the resulting wheel unloading factor and duration of contact loss does not reach critical values before the deck acceleration is beyond 30 m/s2.

In EN 1990 A2, a vertical car body acceleration of 1 m/s2 is stipulated as “very good level of comfort” and is indirectly limited by the vertical deck displacement. Good agreement is generally found in the simulations between deck displacement and expected car body acceleration. In the simulations, the limit for car body acceleration is always exceeded before the running safety is compromised.

Place, publisher, year, edition, pages
Stockholm: , 2017. p. 164
Series
TRITA-BKN, ISSN 1103-4289 ; 165
Keywords
non-ballasted railway bridges, slab track, deck acceleration, train–bridge interaction, wheel–rail force, running safety, passenger comfort, car body acceleration
National Category
Infrastructure Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-228374 (URN)
Projects
TRV 2016/56769
Note

QC 20180604

Available from: 2018-05-23 Created: 2018-05-23 Last updated: 2018-06-04Bibliographically approved
Svedholm, C. & Andersson, A. (2016). Designdiagram för förenklad dynamisk kontroll av järnvägsbroar. Stockholm: KTH Royal Institute of Technology
Open this publication in new window or tab >>Designdiagram för förenklad dynamisk kontroll av järnvägsbroar
2016 (Swedish)Report (Other academic)
Abstract [sv]

I följande rapport redovisas så kallade designdiagram för dynamisk kontroll av järnvägsbroar. Syftet är att dessa ska kunna användas i tidiga skeden som en första bedömning om en given bro har möjlighet att klara kraven på komfort och trafiksäkerhet enligt SS-EN 1990, avsnitt A2.4.4.

Kraven baseras på vertikal acceleration och vertikal nedböjning av brodäcket samt vinkeländring vid upplag. Baserat på spännvidd och brons lägsta egenfrekvens kan erforderlig massa samt styvhet läsas av direkt i diagrammen.

Diagrammen gäller endast för broar med ballastfria spårsystem och största hastighet sth = 320 km/h. Diagrammen är framtagna baserat på en 2D balkmodell med konstant massa och styvhet samt fasta upplag och är giltiga endast under dessa förutsättningar.

Abstract [en]

In this report, so called design charts for dynamic assessment of railway bridges are presented. The aim is to use these diagrams in early stage design of bridges, to determine if they are likely to comply with the requirements for riding comfort and traffic safety stated in SS-EN 1990, section A2.4.4.

The requirements are based on vertical acceleration and vertical displacement of the bridge deck, as well as end rotation at supports. Based on the span length and the fundamental natural frequency, the required mass and stiffness can be obtained directly from the diagrams.

The diagrams are only valid for bridges with ballastless track systems and an allowable speed sth = 320 km/h. The diagrams are developed based on a 2D beam model with constant mass and stiffness and fixed supports. The diagrams are only valid under these assumptions.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2016. p. 54
Series
TRITA-BKN. Rapport, ISSN 1103-4289 ; 157
Keywords
järnvägsbro, dynamik, höghastighetståg, ballastfria spår, acceleration.
National Category
Infrastructure Engineering
Identifiers
urn:nbn:se:kth:diva-182658 (URN)
Funder
Swedish Transport Administration, TRV 2015/101355
Note

QC 20160223

Available from: 2016-02-22 Created: 2016-02-22 Last updated: 2016-02-25Bibliographically approved
Zäll, E., Karoumi, R., Ülker-Kaustell, M. & Andersson, A. (2016). Evaluation of load model for crowd-induced vibrations of footbridges. In: IABSE Congress Stockholm, 2016: Challenges in Design and Construction of an Innovative and Sustainable Built Environment. Paper presented at 19th IABSE Congress Stockholm 2016: Challenges in Design and Construction of an Innovative and Sustainable Built Environment, 21 September 2016 through 23 September 2016 (pp. 65-72). International Association for Bridge and Structural Engineering (IABSE)
Open this publication in new window or tab >>Evaluation of load model for crowd-induced vibrations of footbridges
2016 (English)In: IABSE Congress Stockholm, 2016: Challenges in Design and Construction of an Innovative and Sustainable Built Environment, International Association for Bridge and Structural Engineering (IABSE) , 2016, p. 65-72Conference paper, Published paper (Refereed)
Abstract [en]

Due to a trend in designing light and slender structures, many modern footbridges are prone to excessive vibrations. Severely vibrating footbridges can give rise to discomfort for the pedestrians. Therefore, during the last decades, pedestrian-induced vibrations of footbridges have become a subject of great interest. In this study, the performance of a coupled crowd-structure model, where the bridge is described using its first two modes of vibrations and each pedestrian is described as a moving mass-spring-damper system, in combination with a walking load, is evaluated. The model is used to estimate vertical deck accelerations of a real footbridge which is known to be susceptible to vibrations, and the results are then compared to measurements. The model performs satisfactory in the time domain, but poorly in the frequency domain, which is concluded to be mainly due to discrepancies in the simulated load compared to the measured load.

Place, publisher, year, edition, pages
International Association for Bridge and Structural Engineering (IABSE), 2016
Keywords
Footbridge, Load model, Pedestrian-induced vibrations, Walking load, Footbridges, Frequency domain analysis, Sustainable development, Vibrations (mechanical), Frequency domains, Induced vibrations, Load modeling, Measured loads, Slender structures, Structure modeling, Walking loads, Structural design
National Category
Civil Engineering
Identifiers
urn:nbn:se:kth:diva-216887 (URN)2-s2.0-85019004700 (Scopus ID)9783857481444 (ISBN)
Conference
19th IABSE Congress Stockholm 2016: Challenges in Design and Construction of an Innovative and Sustainable Built Environment, 21 September 2016 through 23 September 2016
Note

Conference code: 127207; Export Date: 24 October 2017; Conference Paper; Correspondence Address: Zäll, E.; KTH Royal Institute of TechnologySweden; email: ezall@kth.se. QC 20171031

Available from: 2017-10-31 Created: 2017-10-31 Last updated: 2018-05-24Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-8926-2140

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