TY - CONF A1 - Auersch, Lutz T1 - A mid-frequency component of train-induced ground vibration due to scattered axle impulses and the irregularities of the soil and ballast N2 - The passage of the train is dominated by the impulses of the static axle loads. The response of the regular homogeneous and irregular soils has been calculated by the finite-element method in frequency domain. The superposition of the impulse responses yields the quasi-static component of the ground vibration which is restricted to very low frequencies and to the close near-field of the track. In case of an irregular soil or ballast of which the stiffness varies randomly in space, a mid-frequency ground vibration component is generated by the scattering of the axle impulses. Measurements will be shown which prove the existence of the mid-frequency ground vibration component and the unique explanation by the scattered axle impulses: many international measurements with a raised mid-frequency component, axle-box measurements with a too low mid-frequency dynamic load, amplitude-speed dependencies which are incompatible with irregularity-induced dynamic loads, and ground vibration reductions due to stiff track elements. T2 - International Conference on Noise and Vibration Engineering (ISMA/USD) CY - Online meeting DA - 07.09.2020 KW - Ground vibration KW - Railway KW - Irregular soil KW - Irregular ballast KW - Axle impulses PY - 2020 SP - 2611 EP - 2625 PB - KULeuven CY - Leuven AN - OPUS4-51210 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir A1 - Rohrmann, R. T1 - Natural frequencies and modes of poles, beams, floors, road and rail bridges N2 - In the last three decades, the vibrations of many floors and bridges have been measured. The contribution shows some evaluation methods, experimental results and some modelling and theoretical results. Simple evaluation methods have been developed for single and coupled floors. Two coupled beams have been measured in good agreement with the theory. A more complex coupling model has been found for a large wooden floor in a castle consisting of six floor bays which correlates well with the measurements. Damaged and intact poles have been tested by their natural frequencies and damping values, and a fair correlation between the degree of damage and the shift of the frequency. Road bridges have been analysed in detail and some examples are presented. Railway bridges and trains are studied for resonant excitation. The risk of resonance can be estimated in frequency domain by using axle-sequence spectra of the train and the natural frequencies of the bridge. A measurement example shows the amplification, but even stronger the cancellation of the subsequent axle responses. Several high-speed trains and freight trains have been analysed for their potential resonance amplification. T2 - International Conference on Noise and Vibration Engineering (ISMA/USD 2020) CY - Online meeting DA - 07.09.2020 KW - Modalanalyse KW - Bauwerke KW - Bauteile KW - Brücken KW - Achsfolgespektren PY - 2020 SP - 1573 EP - 1585 PB - KULeuven CY - Leuven AN - OPUS4-51211 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Viefhues, Eva A1 - Döhler, M. A1 - Hille, Falk A1 - Mevel, L. T1 - Fault detection for linear parameter varying systems under changes in the process noise covariance N2 - Detecting changes in the eigenstructure of linear systems is a comprehensively investigated subject. In particular, change detection methods based on hypothesis testing using Gaussian residuals have been developed previously. In such residuals, a reference model is confronted to data from the current system. In this paper, linear output-only systems depending on a varying external physical parameter are considered. These systems are driven by process noise, whose covariance may also vary between measurements. To deal with the varying parameter, an interpolation approach is pursued, where a limited number of reference models – each estimated from data measured in a reference state – are interpolated to approximate an adequate reference model for the current parameter. The problem becomes more complex when the different points of interpolation correspond to different noise conditions. Then conflicts may arise between the detection of changes in the eigenstructure due to a fault and the detection of changes due to different noise conditions. For this case, a new change detection approach is developed based on the interpolation of the eigenstructure at the reference points. The resulting approach is capable of change detection when both the external physical parameter and the process noise conditions are varying. This approach is validated on a numerical simulation of a mechanical system. T2 - 21st IFAC World Congress CY - Online meeting DA - 13.07.2020 KW - Linear parameter varying systems KW - Fault detectionchanging KW - Process noise KW - Subspace-based residual KW - Model interpolation PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524652 DO - https://doi.org/10.1016/j.ifacol.2020.12.868 SN - 2405-8963 VL - 53 IS - 2 SP - 13668 EP - 13673 PB - Elsevier AN - OPUS4-52465 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Simon, Patrick A1 - Schneider, Ronald A1 - Baeßler, Matthias ED - Yokota, H. ED - Frangopol, D. M. T1 - Bayesian system identification of a reinforced concrete beam subject to temperature variations based on static response data N2 - Changes in the measured response of structural systems can be an indication of structural damages. However, such changes can also be caused by the effect of varying environmental conditions. To detect, localize and quantify changes or damages in structural systems subject to varying environmental conditions, physics-based models of the structural systems have to be applied which explicitly account for the influence of ambient conditions on the structural behavior. Data obtained from the structural systems should be used to calibrate the models and update predictions. Bayesian system identification is an effective framework for this task. In this paper, we apply this framework to learn the parameters of two competing structural models of a reinforced concrete beam subject to varying temperatures based on static response data. The models describe the behavior of the beam in the uncracked and cracked condition. The data is collected in a series of load tests in a climate chamber. Bayesian model class selection is then applied to infer the most plausible condition of the beam conditional on the available data. T2 - Tenth International Conference on Bridge Maintenance, Safety and Management (IABMAS 2020) CY - Online meeting DA - 11.04.2021 KW - Structural systems KW - Bayesian system identification KW - Damage identification KW - Environmental effects KW - Structural health monitoring PY - 2021 DO - https://doi.org/10.1201/9780429279119-125 SP - 934 EP - 941 PB - CRC Press AN - OPUS4-52809 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ritz, Sebastian A1 - Loewe, Anna A1 - Bauer, Jan T1 - Specialties of HAZID-Study for Large Unmanned Underwater Vehicles N2 - This paper scopes the specialties of a hazard identification study for large and extra-large unmanned undersea vehicles (UUVs). A generic node/function structure is derived from different large and extra-large UUV designs, partially own vehicle designs from research projects, and partially from commercial vehicles. For each node, a short overview of its components and the proper function or operations is defined. A set of guide words is used to prompt a hazard discussion for each node, which identifies unwanted functions, resulting in potential hazards and unmitigated consequences. Related to the SafeMASS-Report from DNV, this work concentrates on selected topics of the bridge-related function on voyage, control & monitoring, and abnormal situations. For unmanned vehicles without any person on board, these three topics become more important for underwater vehicles with very limited connectivity or temporary disruptions of communication whereby an operator in a remote-control center could only be provided with rough vehicle or mission states. Therefore, vehicle control, whether in hard- or software, must handle most tasks belonging to the considered functions automatically or autonomously. Hence, the most appropriate reactions of the system to unwanted system behavior must be implemented. This HAZID study could, on the one hand, be used as background for such an implementation, and on the other hand, it is used to verify the implemented actions on the risks and hazards. T2 - OCEANS 2023 - Limerick CY - Limerick, Ireland DA - 05.06.2023 KW - Autonomous underwater vehicles KW - HAZID KW - Risk-based design KW - Safety KW - Cyber security PY - 2023 DO - https://doi.org/10.1109/OCEANSLimerick52467.2023.10244358 SP - 1 EP - 10 PB - IEEE AN - OPUS4-59099 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gerards-Wünsche, Paul A1 - Ratkovac, Mirjana A1 - Schneider, Ronald A1 - Hille, Falk A1 - Baeßler, Matthias T1 - A framework for assessing the reliability of crack luminescence – an automated fatigue crack detection system N2 - The new crack luminescence method offers the possibility of making fatigue surface cracks in metallic materials more visible during inspections through a special coating system. This coating system consists of two layers, whereby the first layer has fluorescent properties and emits visible light as soon as it is irradiated by UV light. The top layer is black and is designed to prevent the fluorescent layer from emitting if no crack develops in the underlying material. The technique proved particularly useful in a wide variety of fatigue tests of steel components under laboratory conditions. Moreover, it has the potential to be used in various industrial applications. To enable industrial deployment and integration into maintenance strategies, a concept study is developed in this contribution, resulting in a qualification framework that can serve as a foundation for determining the reliability of the crack luminescence system in terms of a probability of detection curve. Within this study, factors causing measurement variability and uncertainty are being determined and their influences assessed. Due to the extension of the system by a moving computer vision system for automated crack detection using artificial intelligence, additional long-term effects associated with structural health monitoring systems need to be incorporated into an extended probability of detection study as part of the technical justification. Finally, important aspects and findings related to design of experiments are discussed, and a framework for reliability assessment of a new optical crack monitoring method is presented, emphasizing the influence of various uncertainty parameters, including long-term effects such as system ageing. T2 - SPIE Conference Smart Structures + Nondestructive Evaluation 2023 CY - Long Beach, CA, USA DA - 24.03.2023 KW - Structural Health Monitoring KW - Non-Destructive Evaluation KW - Probability of Detection KW - Reliability KW - Artificial Intelligence KW - Computer Vision KW - Crack Luminescence KW - Wind PY - 2023 SN - 978-1-5106-6086-1 DO - https://doi.org/10.1117/12.2658390 SP - 1 EP - 15 AN - OPUS4-57244 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir T1 - System and damage identification for cars, floors and roofs, bridges, tracks and foundations by modal analyses, frequency response functions and moving-load responses N2 - The following objects have been analysed by frequency response functions and moving load responses. A simple modal analysis which is based on the transformed and weighted system equations has been tested for an automotive test car and for many floors in many buildings to get some rules for their natural frequency and damping. Moreover, six neighboured equal, weakly coupled, wooden floors in a castle have been measured by ambient and hammer excitation, and a special method to extract the different mode shapes of the closely spaced natural frequencies has been developed and tested. Different foundations, for which the soil-structure interaction is generally important, have been measured and compared with finite-element boundary-element models of varying soil properties. Similarly by FEBEM calculations, damages in railway tracks have been identified from flexibility functions (frequency response functions) and from the moving-load responses to normal train operation. Rail and foot bridges have been measured during train passages and by quasi-static tests with moving vehicles. The repeatability of the inclinometer measurements has been checked for different passages, passage directions, and measurement campaigns at a six-span foot bridge. Two rail bridges at the Hanover-Würzburg high-speed line have been measured and evaluated for integrity and for the train- and speed-dependent bridge resonances. The relation between the multi-axle and the single-axle excitation can be solved in frequency domain by the axle-sequence spectrum of the vehicle or the whole train. The single axle response has been used to identify track and bridge damages in laboratory and in situ. T2 - 10th International Operational Modal Analysis Conference (IOMAC 2024) CY - Naples, Italy DA - 21.05.2024 KW - Weakly coupled floors KW - Bridge passage KW - Track damage KW - Foundation-soil interaction KW - Flexibility function KW - Moving load response PY - 2024 SN - 978-3-031-61420-0 DO - https://doi.org/10.1007/978-3-031-61421-7_19 SN - 2366-2557 SP - 187 EP - 195 PB - Springer Nature Switzerland AG CY - Cham, Schweiz AN - OPUS4-61248 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz T1 - Reduction of ground-induced building vibrations by kinematic and inertial soil-structure interac-tion and by base isolation N2 - Many buildings on the soil have been measured and the transfer function freefield-to-building is ana-lysed. In general, an amplification at low frequencies, an amplification for the floor resonances, and a reduction for higher frequencies can be observed. Most of the measurement examples show a flexible behaviour along the height of the buildings. The prediction of building vibration consists typically of three steps. At first, the dynamic stiffness of the foundation and secondly the kinematic soil-structure interaction has to be calculated for example by the combined finite-element boundary-element meth-od. The stiffness of the foundation reduces the incoming waves (the kinematic interaction). Finally, the inertial interaction of the building with the foundation soil is calculated by the conventional finite ele-ment method where the dynamic foundation stiffness from the first step is added at the bottom of the building. The building on the compliant soil has a fundamental vertical resonance usually below 10 Hz. A parametrical variation clearly shows the influence of the elasticity of the building on this reso-nance frequency and amplitude. Moreover for column-type office buildings, the low-frequency floor resonances can further reduce this fundamental frequency. A 1-dimensional model has been estab-lished which can well approximate the behaviour of the 3-dimensional building models. It is used to demonstrate the effect of a base isolation with soft elements at the foundation. A rigid building model clearly over-estimates the isolation effect, which is smaller for a model with flexible walls, columns and floors. An even simpler model of an infinitely high building is suggested for the mitigation effect, and the resonance frequency of the rigid building should be replaced by a better performance indica-tor, which is based on the impedance ratio of the isolation and the wall and which can be also ex-pressed as a characteristic frequency. T2 - 30th International Congress on Sound and Vibration CY - Amsterdam, Netherlands DA - 08.07.2024 KW - Building vibrations KW - Base isolation KW - Foundation stiffness KW - Kinematic soil-structure interaction KW - Transfer functions of flexible buildings PY - 2024 SN - 978-90-90-39058-1 SN - 2329-3675 SP - 1 EP - 8 AN - OPUS4-61245 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kemmler, Samuel A1 - Cuéllar, Pablo A1 - Rettinger, C. A1 - Köstler, H. T1 - A Fluid-Solid Coupled Micromechanical Simulation for the Analysis of Piping Erosion During the Seabed Installation of a Suction Bucket Foundation N2 - Suction buckets are a promising concept for the foundations of offshore wind turbines. During the installation process of a suction bucket, localized fluidization of the granular soil, so-called piping erosion, may lead to installation failure. A 3D fluid-solid coupled micromechanical simulation is presented to study the occurrence of piping. An Euler-Lagrangian coupling employs momentum exchange between the fluid phase and the geometrically resolved particles. We investigate the behavior of the soil for three cases with varying prescribed suction velocities. We observe piping in the case with the highest suction velocity by analyzing the deformation of the granular fabric and monitoring the differential pressure. The grains under the bucket wall-tip show the highest hydraulic gradients and forces at the onset of piping. This approach permits a detailed analysis of piping phenomena and brings novel insights on the triggering conditions for piping failure of suction-aided foundations. T2 - TC 105 International Symposium CY - Grenoble, France DA - 23.09.2024 KW - Micromechanical simulation KW - Piping erosion KW - Suction bucket foundation PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629461 DO - https://doi.org/10.1088/1755-1315/1480/1/012024 SN - 1755-1307 VL - 1480 IS - 1 SP - 1 EP - 4 PB - IOP Publishing AN - OPUS4-62946 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hille, Falk A1 - Schneider, Ronald A1 - Simon, Patrick A1 - Herrmann, Ralf A1 - Baeßler, Matthias ED - Döhler, Michael ED - Mélot, Adrien ED - Aenlle Lopez, Manuel T1 - System identification and model calibration of a steel road bridge N2 - The Bundesanstalt für Materialforschung und -prüfung (BAM), in cooperation with the Netherlands Organization for Applied Scientific Research (TNO), is working on a framework for integrating frequently updated structural models into an asset management process for bridge structures. A multi-span steel road bridge was selected as a test case for the development of this framework. In order for the structural model to represent the real behavior of the bridge with sufficient accuracy, model calibration is required. In this case, we have planned to calibrate the model based on the dynamic response of the bridge. To determine its dynamic properties, a multi-setup operational modal analysis was performed on one of the bridge spans. In parallel, a structural model of the span was developed based on the available design and service life information. Both eigenfrequencies and mode shapes were used as reference parameters to calibrate the model. A sensitivity analysis was performed to identify the most influential design parameters. Subsequently, a genetic algorithm was applied for minimizing the difference between measured and simulated characteristic responses. In the proposed paper, we summarize the measurements as well as the determination of the modal response of the bridge and describe the process of calibration of the structural model using the identified dynamic response. T2 - 11th International Operational Modal Analysis Conference (IOMAC 2025) CY - Rennes, France DA - 20.05.2025 KW - Bridge structure KW - Operational modal analysis KW - Model calibration PY - 2025 SN - 978-84-09-75120-4 SP - 114 EP - 121 PB - International Group of Operational Modal Analysis CY - Gijón, Spain AN - OPUS4-64416 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir A1 - Rohrmann, Rolf ED - Döhler, Michael T1 - Modal analysis of road and rail bridges for damage detection and resonance prediction N2 - In the 1980s, the Federal Institute of Material Research and Testing started with modal analysis measurements of some bridges before and after repair. For one of the bridges, a structural health monitoring was installed 1994 which is still working up to now. It has been modified and extended several times. The monitoring was extended from the critical span to three neighbouring spans. A modal analysis of the whole bridge with seven spans have been done three times, twice together with EMPA of Switzerland. Additional calibration measurements have been done and additional evaluation procedures have been implemented for the monitoring of the steadily increasing loads from the road traffic. Additional sensors were installed such as strain gauges, crack-width, and temperature sensors. The strong influence of the temperature on the natural frequencies has been studied over the years. Later, a temperature compensation has been established and a weak aging trend has been found in the monitoring data. Now, the bridge will be demolished and replaced by a new bridge. Some results of this long-term monitoring will be shown and possible damages (changes of the pre-stress or the support structure) will be discussed. A second application of modal analysis will be demonstrated: the prediction of the resonances due to passing trains. The response of a bridge to passing trains can be calculated in frequency domain as the multiplication of three spectra, the axle sequence spectrum of the train, the transfer function of the bridge, and the modal force spectrum of a single passing load. A resonance occurs if a maximum of the train spectrum coincides with the maximum of the bridge spectrum. The amplitude at this resonance is strongly influenced by the modal force spectrum which is identical to the frequency or wavenumber spectrum of the corresponding mode shape. Therefore, modal analysis from calculation, impact measurements, wind and train measurements are necessary for the prediction of the resonance occurrence and amplification. Examples of mode shape spectra for single or multi-span bridges with simply supported or continuous spans will be shown, and some relations between mode shapes and resonance amplifications will be concluded. T2 - 11th International Operational Modal Analysis Conference (IOMAC) CY - Rennes, France DA - 20.05.2025 KW - Bridge monitoring KW - Multi-span bridges KW - Damage detection KW - Resonance PY - 2025 SP - 39 EP - 46 PB - INRIA CY - Rennes AN - OPUS4-63473 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Song, Jiaojiao T1 - Analysis of intact and damaged (floating) slab tracks by finite-element boundary-element models and by measurements N2 - The damage detection and repair control have become important tasks for slab tracks. Different intact and damaged slab tracks have been investigated theoretically and experimentally for train passages and hammer impacts. The following damages have been considered: The loss of contact between the sleeper and the track slab, between the track slab and the base slab, and between the base slab and the base layer. At first, a slab track with a gap between the track slab and the base layer has been calculated by the combined finite-element boundary-element method which correctly incorporates the behaviour of the infinite soil. The basic results are the track displacements of the rail, the track slab, and the base layer along the track which are caused by a single axle load. These solutions are properly superposed for to get the complete train load. The influence of track and soil parameters and of the track damage has been analysed. For the intact track, the compliance of the soil is dominant whereas the track bending stiffness becomes more important for the damaged track. By comparing the calculated results with the measurements, the length of the gap could be quantified. A slab track with a loose sleeper (without contact to the supporting track slab) was analysed by the transfer function between the displacements and the hammer force (receptance functions) where a resonance appeared in case of the damage. Differences between the different track elements confirmed the detection of the damage. A floating slab track with a thin rubber layer has been investigated for a possible gap between the base slab and the base layer. The behaviour of the intact track has been calculated by a wavenumber-domain method, and the same behaviour has been found in the measurements at several track sections, indicating that there is no damage. Finally, a floating slab track with steel springs and viscous fluid dampers has been measured in the Tongji laboratory. The modes of the floating track slab and the transfer function with corresponding resonances have been calculated and successfully compared with results from wheelset drop tests. T2 - Third International Conference on Rail Transportation (ICRT2024) CY - Shanghai, China DA - 07.08.2024 KW - Railway track KW - Damage KW - Vibration measurement KW - Finite element method KW - Boundary element method KW - Frequency response function KW - Moving load response KW - Floating slab track PY - 2025 SN - 978-0-7844-8594-1 SP - 591 EP - 600 AN - OPUS4-61267 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baeßler, Matthias A1 - Simon, Patrick ED - Cunha, Álvaro ED - Caetano, Elsa T1 - Review of Ballasted Track Destabilization on Shake Table Tests N2 - Shake table tests have been used for a long time to understand the densification and fluidization of granular materials. While purely vertical shaking is quite unlikely to be found in vibration analysis when it comes to granular materials as soils, it has been found that the vertical vibration of railway bridge support structures can affect the fabric of the ballasted track on top. Starting from the experience at French railway lines with destabilizing track conditions on short bridges in high speed lines in the 1990s, various shake table test configurations have been used to investigate the destabiliza-tion of ballast at high acceleration levels. This article describes the effects of the variously investigated dynamic excitations of railway bridges on the bal-lasted track itself. T2 - 11th International Conference on Experimental Vibration Analysis for Civil Engineering Structures (EVACES 2025) CY - Porto, Portugal DA - 02.07.2025 KW - Infrastructure KW - Ballasted track KW - Ballast KW - Railway bridge dynamics PY - 2025 SN - 978-3-031-96105-2 DO - https://doi.org/10.1007/978-3-031-96106-9_62 SP - 595 EP - 604 PB - Springer CY - Cham AN - OPUS4-64265 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz T1 - Characteristic Frequencies of Train-Induced Bridge, Track, Ground and Building Vibrations – Excitation and Mitigation N2 - The characteristic frequencies of train-induced vibrations are discussed in theory and experiment following the propagation of vibrations from the source to the receiver: 1. Out-of-roundness frequencies of the wheels, 2. sleeper-passage frequency, 3. the vehicle-track eigenfrequency, 4. band frequency of the impulses of the passing static axle loads, 5. car-length frequency and multiples, 6. axle-distance frequencies with two characteristic zeros, 7. bridge eigenfrequencies, 8. the cut-on frequency due to the layering, and 9. the cut-off frequency due to the material damping of the soil, 10. the building-soil eigenfrequency, 11. as a rigid building or flexible wall/column mode, 12. floor eigenfrequencies, 13. acoustic room resonances, 14. the „resonance“ frequency or cut-off frequency of a base isolation. Coincidences of some of these characteristic frequencies or frequency ranges can be typically problematic and mitigation measures at the track or at the building can be necessary. The bridge response to the passing static loads is deter¬mined by the axle-sequence spectrum, the eigenfrequency (transfer function) of the bridge, and the modal force or mode shape spectrum. The ground vibration has typically high frequencies for a stiff soil and low frequencies for a soft soil. The high amplitudes between the zeros of the axle-sequence spectrum are often measured in the ground vibrations, and they can be mitigated by soft support elements or a higher bending stiffness of the track. T2 - EVACES 2025 CY - Porto, Portugal DA - 02.07.2025 KW - Train-induced vibration KW - Vehicle excitation KW - Track response KW - Bridge resonance KW - Ground vibration KW - Soil-building transfer KW - Floor resonance KW - Axle-sequence spectrum KW - Vehicle-track eigenfrequency KW - Axle impulses PY - 2025 SN - 978-3-031-96113-7 DO - https://doi.org/10.1007/978-3-031-96106-9_77 VL - 2025 SP - 1 EP - 8 PB - Springer CY - Cham, Schweiz AN - OPUS4-63655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Simon, Patrick A1 - Baeßler, Matthias ED - Cunha, Álvaro ED - Caetano, Elsa T1 - On the reassessment of bridge superstructure vibrations for high-speed traffic N2 - The acceleration thresholds of bridge superstructures remain critical for designing and reassessing railway bridges on high-speed lines, with ballasted track systems historically limited to 3.5 m/s2 vertical accelerations due to destabilization risks. As part of the European InBridge4EU project, this study addresses methodological uncertainties in linking vertical bridge vibrations to lateral track creep—a key focus area for modernizing assessment protocols. A comparative analysis of two acceleration postprocessing methods (peak identification vs. fatigue-derived rainflow counting) as part of a recently proposed framework was conducted using an example bridge and train combination. Results demonstrate that rainflow counting yields more conservative creep estimates with the bulk of cumulative vibration-induced creep attributable to accelerations exceeding 3 m/s2. However, discretizing acceleration ranges into 1 m/s2 bins introduced significant errors compared to continuous cycle data, highlighting sensitivity to analysis parameters. These findings underscore the complexity of reconciling laboratory-derived harmonic vibration models with real-world bridge dynamics, where non-uniform acceleration patterns dominate. The research directly informs ongoing efforts to refine standardized criteria for ballasted track stability, particularly through the InBridge4EU project’s systematic re-evaluation of vibration limits and their engineering implications. By quantifying discrepancies between computational approaches, this work advances the development of robust protocols for predicting track degradation under high-speed operational loads. T2 - 11th International Conference on Experimental Vibration Analysis for Civil Enginering Structures (EVACES 2025) CY - Porto, Portugal DA - 02.07.2025 KW - Infrastructure KW - Railway bridges KW - Ballast destabilization KW - Acceleration limit KW - Ballasted track KW - Rainflow counting PY - 2025 SN - 978-3-031-96105-2 DO - https://doi.org/10.1007/978-3-031-96106-9_53 VL - 675 SP - 506 EP - 515 PB - Springer CY - Cham AN - OPUS4-64267 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liao, Chun-Man A1 - Bernauer, F. A1 - Niederleithinger, Ernst A1 - Igel, H. A1 - Hadziioannou, C. T1 - Assessment of prestress loss in a large-scale concrete bridge model under outdoor condition N2 - Environmental conditions affect the accuracy of field measurements used to monitor civil structures. Previous studies have shown that measured dynamic responses often lack the sensitivity needed for effective localized damage detection. To address this issue, our study focuses on distinguishing environmental effects from damage related effects in measured data to enhance vibration-based damage identification methods. Experimentally, the problem of prestress loss in a prestressed concrete bridge model was examined. By adjusting the pre-stressing force in a large-scale concrete bridge model, cracking phenomena were observed. To demonstrate field monitoring of a large-scale prestressed structure, noise recording was performed and the measurement data was analyzed with operational modal analysis. Additionally, ultrasonic testing, known for its high sensitivity in damage localization, was used to cross-check the structural damage. Seismic and coda wave interferometry were also employed to estimate wave velocities, providing insights into the level of prestress loss and temperature sensitivity. Ultimately, these measurable wave properties help to overcome the uncertainties associated with traditional vibration-based damage detection methods. T2 - EVACES 2025 CY - Porto, Portugal DA - 02.07.2025 KW - Prestress Loss KW - NDT KW - Ambient Vibration KW - Ultrasonic Testing KW - Coda Wave Interferometry KW - Seismic Interferometry PY - 2025 SN - 978-3-031-96105-2 DO - https://doi.org/10.1007/978-3-031-96106-9_20 VL - 675 SP - 181 EP - 189 PB - Springer Nature CY - Cham AN - OPUS4-64212 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -