Periodic Reporting for period 1 - InBridge4EU (Enhanced INterfaces and train categories FOR dynamic compatibility assessment of EUropean railway BRIDGEs)
Période du rapport: 2023-09-01 au 2024-12-31
The transition to more sustainable mobility systems is a key priority in making Europe the first climate-neutral continent by 2050. Railways play a crucial role in this effort, but enhancing the resilience and capacity of the network, particularly its lifeline structures, such as bridges, is essential.
In this context, several open points affecting the current INF TSI, as outlined in the ERA Technical Note, remain to be addressed. These include challenges related to Dynamic Train Categories (DTC), the validity limits of static compatibility checks specified in EN15228, the accuracy of dynamic amplification factors and damping values for railway bridges proposed in EN1991-2, and the applicability of deck acceleration limits imposed by EN1990-A2.
InBridge4EU aims to tackle these issues by developing a harmonized method for assessing the dynamic interaction between railway bridges and Rolling Stock (RS) across Europe. Consequently, the economic impact of modifying the aforementioned normative criteria within the European railway bridge landscape will be evaluated. The research conducted in InBridge4EU will ultimately contribute to recommendations for ERA and CEN to update TSIs and Eurocodes. By leveraging advanced train-bridge interaction (TBI) numerical modelling and dynamic analyses, along with the development of bridge and RS databases, the project will drive progress toward achieving its objectives.
In this context, several open points affecting the current INF TSI, as outlined in the ERA Technical Note, remain to be addressed. These include challenges related to Dynamic Train Categories (DTC), the validity limits of static compatibility checks specified in EN15228, the accuracy of dynamic amplification factors and damping values for railway bridges proposed in EN1991-2, and the applicability of deck acceleration limits imposed by EN1990-A2.
InBridge4EU aims to tackle these issues by developing a harmonized method for assessing the dynamic interaction between railway bridges and Rolling Stock (RS) across Europe. Consequently, the economic impact of modifying the aforementioned normative criteria within the European railway bridge landscape will be evaluated. The research conducted in InBridge4EU will ultimately contribute to recommendations for ERA and CEN to update TSIs and Eurocodes. By leveraging advanced train-bridge interaction (TBI) numerical modelling and dynamic analyses, along with the development of bridge and RS databases, the project will drive progress toward achieving its objectives.
InBridge4EU is organized into 7 Work Packages (WP), where WP1 to WP5 focus on technical aspects, WP6 addresses normative recommendations, and WP7 is dedicated to coordination.
In WP1, preliminary Rolling Stock (RS) data has been collected, encompassing 2,817 passenger and 137,211 freight train formations. Ongoing work focuses on defining critical train parameters using timestep calculations and Spectral Methods (SM). The limitations of current SM approaches have been identified, with the Residual Influence Line (LIR) method preferred over the Decomposition of Excitation in Resonance (DER). Efforts are underway to enhance these methods by incorporating non-sinusoidal mode shapes. Additionally, DTC are being analysed to generalize proposals for Multi-Unit (MU) classes in EN15528 for compatibility checks. Lastly, research is ongoing to establish the validity limits of static compatibility checks, including parameter studies to determine permissible speed limits for each train category.
Regarding WP2, the project initially required selecting 50 bridges from 3 railway lines with a maximum speed of 160 km/h, 3 lines of 200 km/h, and 3 high-speed (HS) lines across 5 countries. The consortium exceeded these requirements by selecting 522 bridges from 10 lines, including 2 in Spain, 1 in Portugal, 2 in Germany, 3 in France, and 2 in Sweden. Bridge properties have been collected by the partners with the support of their respective national Infrastructure Managers (IMs). The bridge database structure was defined and became operational in 2024. Additionally, WP2 partners have agreed on the numerical models for all 522 bridges, which will be used for the simplified dynamic analyses planned in the next tasks.
Regarding WP3, data from Swedish bridges and track irregularity recordings have been collected. In 2024, efforts have been focused on simulating the dynamic amplification factor φ˝ considering a comprehensive database of recorded track irregularities. The results have been analyzed using statistical methods, leading to the development of a preliminary formula for the dynamic factor, which depends on bridge span length, train speed, and track quality.
As for WP4, experimental data from approximately 100 bridges has been collected and integrated into the bridge database. This dataset includes around 1000 time series of train passages, from which damping has been estimated using the Multi-Criteria Optimization and Covariance-Driven Stochastic Subspace Identification (SSI-COV) methods. Benchmark comparisons between these methods have yielded satisfactory results. Finally, damping evaluations for scenarios resembling resonant conditions are currently being analysed.
In WP5, a literature review and responses from a questionnaire sent to international experts guided the design and construction of the shake table rig at Bundesanstalt für Materialforschung und -prüfung (BAM) for studying deck acceleration limits due to ballast instability. Experimental tests on a full-scale bridge in Sweden has also been conducted, and the data is currently being analysed. The first tests at the BAM rig have been completed and are expected to serve as validation and further input for Discrete Element Method (DEM) simulations. For ballastless bridges, TBI analyses were performed, leading to preliminary conclusions that suggest lack of correlation between deck acceleration and running safety. Additionally, a new algorithm was developed to calculate partial safety factors for ballasted track bridges.
WP6 focuses on defining the normative recommendations derived from the technical WPs (WP1–WP5), hence, it is running as expected in parallel with them.
Finally, in WP7, project management is being coordinated by the University of Porto, which is responsible for ensuring the submission of deliverables, meeting milestones, and managing risks. So far, all milestones and deliverables are on schedule. Additionally, general meetings have been organized during Reporting Period 1 (RP1), including the kick-off meeting in Porto (10/2023), the 1st Regular Technical Meeting (RTM1) held online (02/2024), and RTM2 in Berlin (09/2024). Dissemination activities have also been carried out during RP1, including participation in multiple conferences and the publication of 8 scientific articles.
In WP1, preliminary Rolling Stock (RS) data has been collected, encompassing 2,817 passenger and 137,211 freight train formations. Ongoing work focuses on defining critical train parameters using timestep calculations and Spectral Methods (SM). The limitations of current SM approaches have been identified, with the Residual Influence Line (LIR) method preferred over the Decomposition of Excitation in Resonance (DER). Efforts are underway to enhance these methods by incorporating non-sinusoidal mode shapes. Additionally, DTC are being analysed to generalize proposals for Multi-Unit (MU) classes in EN15528 for compatibility checks. Lastly, research is ongoing to establish the validity limits of static compatibility checks, including parameter studies to determine permissible speed limits for each train category.
Regarding WP2, the project initially required selecting 50 bridges from 3 railway lines with a maximum speed of 160 km/h, 3 lines of 200 km/h, and 3 high-speed (HS) lines across 5 countries. The consortium exceeded these requirements by selecting 522 bridges from 10 lines, including 2 in Spain, 1 in Portugal, 2 in Germany, 3 in France, and 2 in Sweden. Bridge properties have been collected by the partners with the support of their respective national Infrastructure Managers (IMs). The bridge database structure was defined and became operational in 2024. Additionally, WP2 partners have agreed on the numerical models for all 522 bridges, which will be used for the simplified dynamic analyses planned in the next tasks.
Regarding WP3, data from Swedish bridges and track irregularity recordings have been collected. In 2024, efforts have been focused on simulating the dynamic amplification factor φ˝ considering a comprehensive database of recorded track irregularities. The results have been analyzed using statistical methods, leading to the development of a preliminary formula for the dynamic factor, which depends on bridge span length, train speed, and track quality.
As for WP4, experimental data from approximately 100 bridges has been collected and integrated into the bridge database. This dataset includes around 1000 time series of train passages, from which damping has been estimated using the Multi-Criteria Optimization and Covariance-Driven Stochastic Subspace Identification (SSI-COV) methods. Benchmark comparisons between these methods have yielded satisfactory results. Finally, damping evaluations for scenarios resembling resonant conditions are currently being analysed.
In WP5, a literature review and responses from a questionnaire sent to international experts guided the design and construction of the shake table rig at Bundesanstalt für Materialforschung und -prüfung (BAM) for studying deck acceleration limits due to ballast instability. Experimental tests on a full-scale bridge in Sweden has also been conducted, and the data is currently being analysed. The first tests at the BAM rig have been completed and are expected to serve as validation and further input for Discrete Element Method (DEM) simulations. For ballastless bridges, TBI analyses were performed, leading to preliminary conclusions that suggest lack of correlation between deck acceleration and running safety. Additionally, a new algorithm was developed to calculate partial safety factors for ballasted track bridges.
WP6 focuses on defining the normative recommendations derived from the technical WPs (WP1–WP5), hence, it is running as expected in parallel with them.
Finally, in WP7, project management is being coordinated by the University of Porto, which is responsible for ensuring the submission of deliverables, meeting milestones, and managing risks. So far, all milestones and deliverables are on schedule. Additionally, general meetings have been organized during Reporting Period 1 (RP1), including the kick-off meeting in Porto (10/2023), the 1st Regular Technical Meeting (RTM1) held online (02/2024), and RTM2 in Berlin (09/2024). Dissemination activities have also been carried out during RP1, including participation in multiple conferences and the publication of 8 scientific articles.
The outcomes of this project will have a clear impact on the current European standards related with bridge dynamics. The main results that will arise from it are:
WP1:
• Development of wide database of RS.
• Development of enhanced SMs for assessing bridge dynamic responses.
• Development of DTCs to speed up dynamic compatibility checks.
• Definition of limits of validity of the static compatibility checks in EN15528, which may be reflected in the INF TSI.
WP2:
• Development of a database of representative bridges of the European railway network.
• Identification of worst-case combinations of critical parameters for existing bridges to simplify the train-bridge route compatibility checks.
WP3:
• Revision of the formulae for φ’ and φ’’ from EN1991-2 to lead to more realistic dynamic amplifications.
WP4:
• Revision of bridge structural damping defined in EN1991-2 to avoid overestimations of railway bridge responses.
WP5:
• Revision of the deck acceleration criterion from EN1990 to define limits and safety margins backgrounded by scientific research.
WP1:
• Development of wide database of RS.
• Development of enhanced SMs for assessing bridge dynamic responses.
• Development of DTCs to speed up dynamic compatibility checks.
• Definition of limits of validity of the static compatibility checks in EN15528, which may be reflected in the INF TSI.
WP2:
• Development of a database of representative bridges of the European railway network.
• Identification of worst-case combinations of critical parameters for existing bridges to simplify the train-bridge route compatibility checks.
WP3:
• Revision of the formulae for φ’ and φ’’ from EN1991-2 to lead to more realistic dynamic amplifications.
WP4:
• Revision of bridge structural damping defined in EN1991-2 to avoid overestimations of railway bridge responses.
WP5:
• Revision of the deck acceleration criterion from EN1990 to define limits and safety margins backgrounded by scientific research.