Dr. Lucjan Janas
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Academic Career Length
13Years (2014-Present)
(Calculated once Scilit publication data is synced: current year − year of first publication + 1)
Representative Publications
View All Publications1 December 2019 in Journal of Bridge Engineering
Journal Article
Orthotropic steel decks have been applied after World War II to long-span bridges due to several advantages, such as light weight, high strength, rapid construction, durability, and life-cycle economy. However, depending on the relative slenderness of their components these decks may be quite susceptible to traffic-induced fatigue cracks. Therefore, fatigue problems in orthotropic steel bridge decks and predicting the remaining fatigue life of their welded details are nowadays a challenging problem for bridge engineers and researchers. The recommendations for the estimation of the remaining fatigue life of steel bridges recently prepared by the European Convention of Constructional Steelwork (ECCS) were applied to predict the remaining fatigue life of an existing orthotropic deck bridge built in 1981. This approach follows the principles and application rules in the Eurocodes. Detailed fatigue calculation and supplementary testing were performed for two details, which were estimated to be the most critical for fatigue according to preliminary evaluation. The prediction showed that the remaining fatigue life of the details is practically unlimited despite nearly 40 years of service.
Journal Article
Lucjan JanasThe paper presents the results of vibroacoustic tests of a plate girder railway bridge consisting of two parallel dilated structures and a common ballast trough. The requirements currently set for railway bridges relate to, among others, vibrations considered as one of the criteria for traffic safety and to noise emissions that may pose a threat to the environment. In this article, the results of tests conducted on vibrations of elements of the analyzed structure are presented, and the level of these vibrations in terms of meeting the requirements of the European standards is assessed. Vibrating criteria of structure performance were checked, and safety was assessed. The results of noise measurements in the vicinity of the analyzed bridge are also presented, and the environmental impact of this structure is determined. The test results show that the bridge meets the requirements for vibration acceleration and noise. An increased acoustic emission in the analyzed case does not pose a significant threat, but if this type of structure was on high supports in an urbanized area, it would be a nuisance to the environment.
21 December 2018 in The Baltic Journal of Road and Bridge Engineering
Journal Article
This paper presents a novel approach to the creation of a ranking list of bridges with the highest priority for repair, renovation or exchange. Two main aspects addressed herein are studied. First concerning parameters, which must be taken into account while creating the list of bridges with priority for repair or renovation. Second concerning proposition of algorithms for creating such list. A set of factors that affect this priority has been created; the three main ones were selected: technical condition factor, safety factor and the importance for the roads network factor. Three self-reliant algorithms of the ranking list creation are presented. One of them is the so-called “expert algorithm”, based on artificial neural networks – gives the best result and has been indicated as the recommended one. This algorithm, engaging back-propagation multilayer artificial neural network, is implemented in the General Directorate for National Roads and Motorways in Poland and is applied as a supporting tool in managing road-engineering structures.
23 February 2019 in IOP Conference Series: Materials Science and Engineering
Conference Paper
Lucjan JanasThis paper presents the results of research of noise in the surrounding of three plate girder railway bridges of different type of deck structure. One of the objects has a track fixed directly to steel plate of the deck, next object has a deck in form of an open grid. The last of the objects is a bridge, where the track was laid on ballast. Sources of noise in these bridges were identified. Reasons for an increase of noise when a train crosses the bridges can be generally divided into two groups: a) vibrations coming from wheels transmitted through rails to a bridge structure, make its components vibrate; structure elements with large surface may act as membranes of a loudspeaker and emit unwanted sounds; b) in bridges with an open deck the lack of insulation makes the sounds at point-to-point contact of wheels with rails disseminate. The biggest threat to the environment from the noise emission point of view is caused by steel bridges with an open deck and with a steel deck with no ballast. The noise next to the track beyond the bridge depends mostly on the type of train, its speed and wheels condition. The noise under the bridge was almost 15 dB higher than the noise nearby the track beyond the bridge. The level of noise next to the bridge was higher 3.3 to 10 dB. Nowadays, the analysis of railway bridges for the emission of sounds should be the standard element in the process of preparation and design of investment projects.
Journal Article
Lucjan JanasExpansion joints mounted on the edges of bridges can cause excessive noise and environmental nuisance. Currently, there are no standardized European methods for assessing the noise of these devices. This article presents the results of investigations of two expansion joint devices: a modular one used for small displacements and a finger one used for large displacements. The method proposed in the Austrian standard was used to evaluate the acoustic effects. The exposure levels of the sound were compared after analyzing 100 reliable car passes through each device. Acoustic signals were recorded and analyzed at three points. In the case of the modular device, the average exposure sound level above the device was 2.6 dB higher than the noise above one outside the device. For a finger device, the difference was 1.2 dB. The latter device can be considered “low-noise”. The amplitude–frequency characteristics of the recorded phenomena were also analyzed to show which frequencies are responsible for excessive noise. The dependence of sound emissions on the speed of cars was also determined. The conducted research has shown that the adopted method can be successfully used for the acoustic evaluation of expansion joint devices.
20 September 2018 in IOP Conference Series: Materials Science and Engineering
Conference Paper
Lucjan JanasThis paper discusses the results of own research of acoustic phenomena in the surrounding of two railway bridges of different type of decks. One of the objects has an open deck with cross girders and stringers, next has an orthotropic deck and track laid on ballast. The biggest threat for the environment is posed by objects with open deck. The extent of increase in noise reaches as much as 20 dB. Objects with ballast may also affect worsening of acoustic climate around the bridge, in particular under the bridge. Reasons for an increase of noise when a train crosses the bridge in general split in-to two groups: - vibrations coming from vehicle wheels, transmitted through rails to a bridge structure make its components vibrate; large surface of structure may act as membranes of a loudspeaker and emit unwanted sounds; - for bridges with open platform the lack of attenuation by the deck (ballast) make the sounds at point-to-point contact of wheels with a rails freely disseminate.
About Me
Lucjan Janas, lecturer, head of an accredited laboratory for structural testing. Employed at the Rzeszów University of Technology - since 1989. Doctoral dissertation: "Vibroacoustic phenomena in plate girder elements of railway bridges" - 1998. As part of his didactic activity, he conducts classes in the following subjects: Bridge maintenance, Transport infrastructure, Bridge tests and monitoring. Lecturer at Bridge Inspector trainings. He conducts research on the assessment of the technical condition of bridge structures, strength and vibroacoustic tests of engineering structures. He led, among other things, load tests of several dozen bridges, including motorway bridges. He is a co-author of the system of road inspections of engineering structures, which is used on national roads and motorways in Poland. Is the main author of the rules for the use of the scale of point assessments of the technical condition and suitability for use of road engineering structures. He is also a co-author of an algorithm supporting decision-making regarding road repairs of engineering structures. Since 2006, he has been the head of the Laboratory of Structural Research at the Faculty of Civil and Environmental Engineering and Architecture, Rzeszow University of Technology in Poland. Under his leadership, the laboratory introduced a management system in accordance with the EN ISO/IEC 17025 standard and obtained the Certificate of Accreditation of the Testing Laboratory.