1. Using weigh-in-motion data to determine bridge dynamic amplification factorJan Kalin, Aleš Žnidarič, Maja Kreslin, 2015, published scientific conference contribution Abstract: The dynamic component of bridge traffic loading is commonly taken into account with a Dynamic Amplification Factor (DAF) - the ratio between the maximum dynamic and static load effects on a bridge. In the design codes, this factor is generally higher than in reality. While this is fine for new bridges that must account for various risks during their life-time, it imposes unnecessary conservativism into assessment of the existing well defined bridges. Therefore, analysis of existing bridges should apply more realistic DAF values. One way of obtaining them experimentally is by bridge weigh-in-motion (B-WIM) measurements, which use an existing instrumented bridge or culvert to weigh all crossing vehicles at highway speeds. The B-WIM system had been equipped with two methods of obtaining an approximation to the static response of the. The first method uses the sum of influence lines. This method relies on accurate axle identification, the failure of which can have a large influence on the DAF value. The other method uses a pre-determined low-pass filter to remove the dynamic component of the measured signal; however an expert is needed to set the filter parameters. A new approach that tries to eliminate these two drawbacks has been developed. In this approach the parameters for the filter are determined automatically by fitting the filtered response to the sum of the influence lines. The measurement of DAF on a typical bridge site agrees with experiments performed in the ARCHES [1] project: dynamic amplification decreases as static loading increases.
Published in DiRROS: 26.09.2025; Views: 265; Downloads: 126
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2. Railway bridge weigh-in-motion systemAleš Žnidarič, Jan Kalin, Maja Kreslin, Peter Favai, Przemyslaw Kolakowski, 2016, published scientific conference contribution Abstract: The paper provides an overview of the development of a railway bridge weigh-in-motion (B-WIM) system, one of the first of its kind for weighing trains in motion. A steel truss bridge in Poland was used for testing the system. Four trains which passed over the bridge were weighed in a rail yard in Warsaw. The conventional road B-WIM system was adapted to calculate the weights of the train carriages using the measured response from the test bridge and the accuracy of the system was assessed. Initial result showed that weights of one of the four trains of known weight were predicted very accurately, but accuracy of the other three trains was poor, with calculated carriage weights deviating by as much as 30% from their actual values. An in-depth analysis showed that these trains were changing velocity as they traversed the bridge and that the large errors were directly correlated to this changing velocity. The standard B-WIM algorithm, which assumed a constant velocity during the passage of a vehicle or train, was adjusted to allow for the effect of this changing velocity. The results improved dramatically, with the vast majority of the calculated wagon weights falling within 5% of their actual values. Further developments tailored the B-WIM algorithm for weighing trains, including the system interface that employs graphics of locomotives and wagons. The development of the railway B-WIM has been a success and has demonstrated that calculations of train weights using instrumented bridges can be efficiently performed.
Keywords: accuracy, B-WIM, measurement error, train, weigh-in-motion
Published in DiRROS: 05.09.2025; Views: 355; Downloads: 158
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4. Znanje, ki pušča sled : petinsedemdeset let Zavoda za gradbeništvo Slovenije : 1949-20242024, professional monograph Keywords: raziskave, laboratoriji, grajeno okolje, digitalizacija, gradnja, materiali, les, potresno inženirstvo, stavbe, trajnostna gradnja, bivanje, ekologija
Published in DiRROS: 12.03.2025; Views: 706; Downloads: 494
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5. Challenges of implementing bridge weigh-in-motion on a century-old steel-riveted railway bridgeDoron Hekič, Mirko Kosič, Jan Kalin, Aleš Žnidarič, Andrej Anžlin, 2024, published scientific conference contribution Abstract: This study explores the challenges and methodologies involved in implementing bridge weigh-in-motion (B-WIM) system on a century-old steel riveted railway bridge. A unique aspect of this study, funded by the EU H2020 Shift2Rail Joint Undertaking, was the adaptation of B-WIM systems to the specific constraints of railway bridges since, traditionally, this technology is used to collect heavy gross vehicle loading data on road bridges. The paper details the experimental setup on an old steel-riveted railway bridge, including sensor placement and calibration processes. It highlights the complexities encountered, such as differences in bridge response due to passenger and other type of trains. It introduces the system calibration strategy using known axle loads from passenger locomotives. The study provides insights into the structural response of old steel bridges under traffic loads, contributing valuable data to the field of railway bridge monitoring and maintenance.
Keywords: bridge, B-WIM, bridge Weigh-in-Motion system, numerical model updating, bridge response measurements, railways
Published in DiRROS: 14.08.2024; Views: 1136; Downloads: 697
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6. Modelling of traffic load effects in the assessment of existing road bridgesDominik Skokandić, Ana Mandić Ivanković, Aleš Žnidarič, Mladen Srbić, 2019, review article Abstract: Traffic load models used for the design of new bridges are based on conservative assumptions and have not been proven efficient for assessing safety of existing bridges. In the case of existing bridges, it is reasonable to use load models that are based on bridge weigh-in-motion data which, in addition to axle loads and spacing of bridge-crossing vehicles, provide information on bridge behaviour under traffic load. This paper provides an overview of traffic load models, as well as guidelines on the use of weigh-in-motion data when assessing condition of existing road bridges.
Keywords: prometna obtežba, tehtanje vozil med vožnjo, mostni WIM, ocenjevanje stanja, obstoječi mostovi, traffic load, weigh-in-motion, bridge WIM, condition assessment, existing bridges
Published in DiRROS: 27.03.2024; Views: 1363; Downloads: 1113
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7. Vehicle–bridge interaction modelling using precise 3D road surface analysisMaja Kreslin, Peter Češarek, Aleš Žnidarič, Darko Kokot, Jan Kalin, Rok Vezočnik, 2024, original scientific article Abstract: Uneven road surfaces are the primary source of excitation in the dynamic interaction between a bridge and a vehicle and can lead to errors in bridge weigh-in-motion (B-WIM) systems. In order to correctly reproduce this interaction in a numerical model of a bridge, it is essential to know the magnitude and location of the various roadway irregularities. This paper presents a methodology for measuring the 3D road surface using static terrestrial laser scanning and a numerical model for simulating vehicle passage over a bridge with a measured road surface. This model allows the evaluation of strain responses in the time domain at any bridge location considering different parameters such as vehicle type, lateral position and speed, road surface unevenness, bridge type, etc. Since the time domain strains are crucial for B-WIM algorithms, the proposed approach facilitates the analysis of the different factors affecting the B-WIM results. The first validation of the proposed methodology was carried out on a real bridge, where extensive measurements were performed using different sensors, including measurements of the road surface, the response of the bridge when crossed by a test vehicle and the dynamic properties of the bridge and vehicle. The comparison between the simulated and measured bridge response marks a promising step towards investigating the influence of unevenness on the results of B-WIM.
Keywords: interakcija vozilo in most, terestično lasersko skeniranje, neravnost vozišča, numerično modeliranje
Published in DiRROS: 26.01.2024; Views: 1855; Downloads: 868
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8. Comprehensive permanent remote monitoring system of a multi-span highway bridgeAndrej Anžlin, Uroš Bohinc, Doron Hekič, Maja Kreslin, Jan Kalin, Aleš Žnidarič, 2021, published scientific conference contribution Abstract: As part of the reconstruction of a multi-span viaduct on a Slovenian highway, a permanent remote monitoring system with over 200 sensors was established. Several parameters are monitored on different parts of the viaduct by means of temperature sensors, accelerometers, strain gauges, long-gauge deformation and Fibre Bragg Grating (FBG) sensors. In this way strains, frequencies and temperatures on external prestressed beam cables, carbon fibre rebarsused for the flexural strengthening of a deck overhang, pier caps and prestressed beams are measured and stored into the on-site central data acquisition system. This paper presents architecture of the permanent bridge monitoring system and preliminary results of the measurements.
Keywords: permanent monitoring, structural health monitoring, bridge WIM, sensors, viaduct
Published in DiRROS: 22.01.2024; Views: 1609; Downloads: 1014
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9. Znanje, ki pušča sled : sedemdeset let Zavoda za gradbeništvo Slovenije 1949-20192019, professional monograph Abstract: V publikaciji je predstavljen Zavod za gradbeništvo Slovenije, ob 70-letnici. V osmih poglavjih je predstavljeno znanstveno-raziskovalno in strokovno delo. V nadaljevanju sledijo poglavja, ki predstavljajo posamezne zanszveno-raziskovalne laboratorije in strokovne službe.
Keywords: Zavod za gradbeništvo Slovenije, ZAG Ljubljana, gradbeništvo, znanstveno-raziskovalna dejavnost, strokovna dejavnost, laboratoriji, predstavitev, 70 let, sedemdeset let, grajeno okolje, digitalizacija, gradnja, les, krožno gospodarstvo, napredni materiali v gradbeništvu, potresi, stavbe, trajnostna gradnja, bivanje, ekologija, voda, zrak, zemlja
Published in DiRROS: 19.01.2024; Views: 1504; Downloads: 858
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10. Knowledge that leaves a mark : seventy years of the Slovenian National Building and Civil Engineering Institute 1949-20192019, professional monograph Abstract: V publikaciji je predstavljen Zavod za gradbeništvo Slovenije ob 70-letnici. V osmih poglavjih je predstavljeno znanstveno-raziskovalno in strokovno delo. V nadaljevanju sledijo poglavja, ki predstavljajo posamezne znanstveno-raziskovalne laboratorije in strokovne službe.
Keywords: Zavod za gradbeništvo Slovenije, ZAG Ljubljana, gradbeništvo, znanstveno-raziskovalna dejavnost, strokovna dejavnost, laboratoriji, predstavitev, 70 let, sedemdeset let, grajeno okolje, digitalizacija, gradnja, les, krožno gospodarstvo, napredni materiali v gradbeništvu, potresi, stavbe, trajnostna gradnja, bivanje, ekologija, voda, zrak, zemlja
Published in DiRROS: 19.01.2024; Views: 1435; Downloads: 793
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