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Wyniki wyszukiwania dla: BRIDGE DESIGN
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Badania doświadczalne segmentu walidacyjnego kompozytowej kładki pieszo-rowerowej
PublikacjaW artykule przedstawiono zakres badań zrealizowanych na segmencie walidacyjnym o długości ~3 m będącym wycinkiem docelowej kompozytowej, powłokowej kładki pieszo-rowerowej. Wykonane testy statyczne i dynamiczne pozwoliły na ocenę pracy konstrukcji i potwierdziły przyjęte na etapie projektowania założenia teoretyczne.
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WERYFIKACJA KONCEPCJI PRZEGUBÓW PLASTYCZNYCH PROJEKTOWANYCH NA ODZIAŁYWANIA SEJSMICZNE WIADUKTU V6 OBWODNICY ISTAMBUŁU
PublikacjaW pracy zawarto wyniki analiz betonowego wiaduktu V6 budowanego w ciągu obwodnicy Istambułu w Turcji realizowanego w ramach projektu Northern Marmara Highway. Przeprawę stanowią dwie niezależne nitki o skrzynkowym przekroju poprzecznym i szerokości 22,00 m. Schemat statyczny obiektu to belka dziewięcioprzęsłowa o długości całkowitej 446,86 m oparta na podporach słupowych o zmiennej sztywności (rys.1) i wysokościach zmieniających...
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MOST PODWIESZONY kreowanie przestrzeni i konsekwencje konstrukcyjne
PublikacjaProjektowanie i budowa - wyzwania dla projektantów i wykonawców mostów. Mosty podwieszone i wiszące ich estetyka i konsekwencje strukturalne. Artykuł dotyczy aspektów estetycznych i konstrukcyjnych zaprojektowanych pylonów dla mostów podwieszonych lub wiszących. Autor zwraca uwagę na fakt, że niezwykłe rozwiązanie konstrukcyjne zastosowane do kładki lub małego wiaduktu może działać prawidłowo dzięki zjawiskom efektu skali. Nadzwyczajne...
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Kompozytowy most dla pieszych. Badania doświadczalne i przygotowanie do projektowania
PublikacjaDysertacja powstała w ramach grantu badawczego NCBiR, pt. „Opracowanie kompozytowych przęseł mostów dla pieszych do zastosowania nad drogami GP”, nr PBS1/B2/6/2013. Głównym celem pracy było wsparcie procesu projektowania kompozytowego mostu pieszo-rowerowego. Zakres pracy obejmuje badania doświadczalne elementów kompozytowych GFRP, walidację modeli obliczeniowych oraz wykorzystanie aparatu analizy wrażliwości do procesu projektowego....
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ZAAWANSOWANE SYMULACJE NUMERYCZNE MES DYNAMIKI MOSTÓW Z WYKORZYSTANIEM PROCEDURY EXPLICITE
PublikacjaDostęp do mocy obliczeniowej superkomputerów oraz możliwość wykorzystania nowoczesnych systemów, np. takich jak Ls-Dyna, pozwala na uzyskanie niezwykle szczegółowych rozwiązań bardzo skomplikowanych problemów inżynierskich. Zagadnienia te dotyczą zakresu statyki/stateczności jak i dynamiki dla rozbudowanych układów konstrukcyjnych zarówno w zakresie nieliniowości materiałowej jak i geometrycznej. Uzyskanie wiarygodnych wyników...
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Stan graniczny nośności dźwigara żelbetowego mostu na zginanie według norm PN-EN 1992-2 oraz PN-S-10042:1991
PublikacjaPraca włącza się w bogaty w ostatnich latach w krajowym piśmiennictwie nurt porównań dwóch generacji norm projektowania mostów z betonu: polskiej - wycofanej, aczkolwiek powszechnie stosowanej oraz europejskiej – wciąż jeszcze wdrażanej do praktyki projektowej. Nowością w stosunku do dotychczasowych publikacji polskich jest szersze ujęcie różnic pomiędzy obydwiema generacjami norm. Poza rozpatrywanymi przez wielu autorów różnicami...
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SENSITIVITY OF PUBLIC PLACES IN GDAŃSK OSOWA DISTRICT
PublikacjaThis paper summarises the results of the research carried out at the University of Ljubljana, Faculty of Architecture, Slovenia, during the PhD visiting period of the first author from the Gdansk University of Technology, Poland, in the framework of the PhD course "Sensitive urban places", leaded by the second author. Focusing to the specific problems of the Gdansk Osowa district in Poland, this research develops the idea of sensitivity...
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Zmodernizowany most Łazienkowski w Warszawie – analizy z wykorzystaniem modelu numerycznego MES
PublikacjaW artykule przedstawiono proces modelowania statycznego przęseł mostu Łazienkowskiego w Warszawie, który został poddany odbudowie po pożarze 14 lutego 2015 r. Sprawdzające obliczenia numeryczne wykonano w związku z badaniami konstrukcji podczas próbnego obciążenia. Przeprowadzono weryfikację obliczeń projektowych i zaprojektowano próbne obciążenie. Podsumowano wyniki analizy i badań. Dodatkowo opisano nową, stalową konstrukcję...
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The health impact of urban parks along waterways
PublikacjaWell designed parks along waterways could promote health and well-being of local inhabitants. The way the human settlements meet water bodies can influence the habits of local population. How people spend their time have significant impact on their health. For example, a team of Japanese scientists has proven that a well designed walk-able green spaces are crucial for the longevity of elderly citizens (Takano T. et al, 2002). Nature...
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Experimental validation and comparison of a SiC MOSFET based 100 kW 1.2 kV 20 kHz three-phase dual active bridge converter using two vector groups
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Cross-Sectoral Inter-Country Linkages under the Belt and Road Initiative: Chinese ICT Services Value Added Inflows to Manufacturing Exports in the New Eurasian Land Bridge Economies
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Bio-inspired Decisional DNA in Machinas and other Man-made Systems: The Way Forward
PublikacjaArtificial bio-inspired intelligent techniques and systems supporting smart, knowledge-based solutions of real world problems which are currently researched very extensively by research teams around the world, have enormous potential to enhance automation of decision making and problem solving for a number of diverse areas including design, manufacturing, Information Technology (IT), social communities of practice, and economics...
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Estakada E2 - kluczowy obiekt Obwodnicy Wałcza
PublikacjaW artykule przedstawiono uwarunkowania i przebieg projektowania estakady E2 z betonu sprężonego w ciągu Obwodnicy Wałcza. Pokazano efekt procesu optymalizacji projektu pierwotnego. Opisano przeprowadzone analizy wynikające z przyjętej technologii nasuwania podłużnego oraz istotne aspekty, które należy poruszyć przy wyborze tej technologii. Zaprezentowano modele numeryczne konstrukcji przęseł i metodę analizy z uwzględnieniem pracy...
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Wielopoziomowy przekształtnik trakcyjny SiC z izolacją od sieci 3kV DC realizowaną za pomocą transformatorów 30kHz do napędów EZT
PublikacjaW referacie przedstawiono wielopoziomowy izolowany kaskadowy przekształtnik DC-AC z tranzystorami SiC MOSFET 1,2kV, przeznaczony do napędów elektrycznych zespołów trakcyjnych (EZT). Zaproponowana konstrukcja przekształtnika, przeznaczonego do pracy przy zasilaniu z sieci trakcyjnej 3kV DC, spełnia założenia energoelektronicznego transformatora trakcyjnego (z ang. Power Electronic Traction Transformer). Budowa modułowa z niskonapięciowych...
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Risking It All or Here Comes the Flood
PublikacjaThe professional reality is interdisciplinary! When city transformation and evolution starts, what are the tools for successful strategies for urban interventions? How does digital planning for digital fabrication processes look like? How dedicated are the new professionals? And how does this all influence the future of bridge design? More than 60 students representing various disciplines of built environment and working together...
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Equivalent axle load factors for design of rigid pavements derived from fatigue criteria
PublikacjaArtykuł przedstawia określenie współczynników równoważności osi dla nawierzchni sztywnych na podstawie kryteriów zmęczeniowych stosowanych w mechanistyczno-empirycznej metodzie projektowania nawierzchni drogowych. Przedstawiono kryteria zmęczeniowe z wybranych metod projektowania i analizy nawierzchni sztywnych. Kryteria te zostały użyte do wyprowadzenia wzorów do obliczania współczynników równoważności obciążenia osi. Stwierdzono,...
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Determination of Peak Impact Force for Buildings Exposed to Structural Pounding during Earthquakes
PublikacjaStructural pounding between adjacent, insufficiently separated buildings, or bridge segments, has been repeatedly observed during seismic excitations. Such earthquake-induced collisions may cause severe structural damage or even lead to the collapse of colliding structures. The aim of the present paper was to show the results of the study focused on determination of peak impact forces during collisions between buildings exposed...
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The application of non-destructive methods in the diagnostics of the approach pavement at the bridges
PublikacjaThe article presents the possibility of using non-destructive methods of road pavement diagnostics as an alternative to traditional means to assess the reasons for premature cracks adjacent to bridge objects. Two scanning methods were used: laser scanning to measure geometric surface deformation and ground penetrating radar (GPR) inspection to assess the road pavement condition. With the use of a laser scanner, an effective tool...
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Road Restraint Systems as a Basis for Roadside Safety Improvement
PublikacjaRoadside-related crashes occur when vehicles run off the road. The majority of the crashes have severe outcomes, especially when an object is hit (tree, pole, supports, front wall of a culvert, barrier). These accidents represent app. 19% of all of Poland's road deaths. Roadside crashes involve: hitting a tree, hitting a barrier, hitting a sign or utility pole, vehicle roll-over on the roadside, vehicle roll-over on a slope and...
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Protection of bridges against stray current corrosion
PublikacjaA case study of Siennicki Bridge stray current corrosion hazard is presented. A corrosion risk was caused by incorrectly designed tram line traction which goes over the bridge. No dielectric insulation between running rails and bridge steel construction was used. A variety of protection methods against stray currents are described. Characteristics of the endangered bridge were described. Impressed current cathodic protection system...
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The effect of fishing basin construction on the behaviour of a footbrdge over the port channel
PublikacjaThe paper analyses possible causes of failure of the rotating footbridge over the Ustka port channel. In July, 2015, strange behaviour of this object was observed in the form of excessive vibrations of bridge platform suspension rods, with the accompanying acoustic effects. A preliminary geotechnical analysis has revealed that this destructive effect was caused by the nearby construction works, namely construction of a fishing...
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DYNAMIC ANALYSIS OF HISTORIC RAILWAY BRIDGES IN POLAND IN THE CONTEXT OF ADJUSTING THEM TO PENDOLINO TRAINS
PublikacjaThe article presents the dynamic analysis of the historic railway bridge in Tczew as an example of the usefulness of such type of bridge for high-speed trains. The model of the bridge and the simulation of rolling stock passage was performed in SOFISTIK program. The scope of work includes experimental studies, the solution of the problem concerning the correct solution features dynamic model takes into account the dependencies...
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Some kind of joints in composite polymer bridges
PublikacjaContemporary, polymer composites bridge structures are of two types: truss or arch structures(with many joints along the length) and beam structures with limited number of joints. Both of them have special types of composite polymer decks. An ideal solution is to join advantages of two types of structuresdescribed below and create long span FRP beam bridge structure system using joints along the length. Theproblem is to find the...
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Modern GFRP Composite Footbridges
PublikacjaApplication of GFRP composites in civil engineering is still not large but already noticeable. Advantages of this material, such as: low volume weight, relatively high stiffness and strength, well fatigue resistance, easiness in shaping, high material damping and high environmental resistance, make it attractive for bridge and in particular foot-bridge designers. It is estimated that nowadays in the world there are realized hundreds...
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Modelling and analysis of medium frequency transformers for power converters
PublikacjaThe evolutions in power systems and electric vehicles, related to the economic opportunities and the environmental issues, bring the need of high power galvanically isolated DC-DC converter. The medium frequency transformer (MFT) is one of its key components, enabled by the increasing switching frequency of modern power semiconductors like silicon carbide transistors or diodes. The increased operating frequency offers small...
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DYNAMIC ANALYSIS OF THE RAILWAY BRIDGES IN POLAND WITH REGARDS TO HIGH-SPEED TRAINS PASSAGE ADJUSTMENT
PublikacjaThe dynamic analysis of the railway bridge in Tczew was carried out in the article as an example of such bridges adaptation suitability to handle high-speed trains. Calculations of railway bridges are greatly complicated and labor-consuming. The bridge model and a rolling stock passage simulation were developed in the SOFISTIK software. Three types of elements were used for the correct mapping of the structure in the calculation...
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Arch bridges under test loadings
PublikacjaThis paper illustrates experience in arch bridges test loadings of the research team of Department of Structural Mechanics and Bridge Structures from the Gdansk University of Technology. The presented calculations results constist the analysis of spatial construction schemes made using the finite elements method (FEM) and its comparison to the field studies. Arch bridges with the longest spans, visualisation of the computational...
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Single-phase power electronics transformer with active functions for smart grid
PublikacjaThis paper presents the control of one cell of a modular single-phase power electronics transformer with active functions for meeting the smart grid concept. In this way, the converter could be used not only as a conventional transformer but also for grid such as reactive power, harmonic elimination and energy storage. The topology of the cell is composed by a bidirectional converter with three stages: a half bridge in the input...
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Load test of new European record holder in span length among extradosed type bridges
PublikacjaThe article presents acceptance load tests of a newly built extradosed MS-3 bridge located along the national road DK-16 near Ostróda (Poland). The structure features significant dimension in European reference scale. It is a new record holder in span length regarding this distinct bridge category. Its length ranges 206 m. Static and dynamic load tests were performed here. The program was extended by entire structural laser scanning...
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OCENA WŁAŚCIWOŚCI STALI STOSOWANEJ W STARYCH OBIEKTACH KOLEJOWYCH
PublikacjaThe scope of the paper is to give an introduction to the assessment subject matter of steel properties used in old railway bridges. The mechanical and chemical properties of construction steel extracted from old steel bridges are generally investigated by tensile tests, impact tests through the Charpy pendulum impact V-notch, and an optical emission spectrometer. Besides descriptions of the tests, the chosen chemical and mechanical...
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Excitation-independent constant conductance isfet driver
PublikacjaA new constant conductance driver for ISFETs sensors has been developed. The proposed circuit maintains the sensor operating point at constant drain-source conductance. The combination of a simple, self-balancing resistance bridge and the subtraction half (or similar fraction) of source-drain voltage from the gate-source voltage provides the independence of output signal from current and voltage drivers instability. The use of...
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EMI mitigation of GaN power inverter leg by local shielding techniques
PublikacjaThis paper presents local shielding techniques applied to a half-bridge inverter leg with the aim to reduce the common mode (CM) current noise at converter’s DC input. The research study is conducted for 650V Enhancement mode Gallium Nitride (GaN) power transistor switches. Main contributors of parasitic capacitances referred to the inverter-leg middle point node are identified. Then, shielding solutions are proposed to reduce...
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Problems of construction projects regarding historic road bridges
PublikacjaThe paper describe the comparison of different approaches to reconstruction and the problems in the selection of implementation for a historic bridge over the Vistula River in Tczew. A compromise reconstruction is shown, taking technical, historical and aesthetic aspects into account, as well as needs of the local community.
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Identyfikacja parametrów dynamicznych want mostu Rędzińskiego we Wrocławiu
Publikacjathe paper presents results of dynamic analysis conducted on stay-cables of rędziński bridge in wrocław. identified in situ dynamic parameters (natural frequency and logarithmic decrement damping ratio) of selected stays were and compared to the values featured in the project.
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Zabezpieczenia antykorozyjne stalowych barierek ochronnych na obiektach mostowych w ujęciu kosztów cyklu ich życia
PublikacjaThe article presents the Life Cycle Costs analysis of steel safety barriers operated in road lane conditions, located on a selected bridge structure. Three corrosion protection systems were proposed, analyzing them in terms of the cost of initial and planned outlays related to maintenance. Based on the LCC analysis for three options, taking into account the 25-year lifetime of the barriers, the optimal solutionwas indicated, i.e....
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Antimicrobial Activity of Chimera Peptides Composed of Human Neutrophil Peptide 1 (HNP-1) Truncated Analogues and Bovine Lactoferrampin
PublikacjaThree chimera peptides composed of bovine lactoferrampin and the analogue of truncated human neutrophil peptide 1 were synthesized by the solid-phase method. In two compounds peptide chains were connected via isopeptide bond, whereas in the third one disulfide bridge served as a linker. All three chimeras displayed significantly higher antimicrobial activity than the constituent peptides as well as their equimolar mixtures. The...
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Multipoint Ultrasonic Diagnostics System of Prestressed T-Beams
PublikacjaThis paper is devoted to the application of ultrasonic wave propagation phenomena for the diagnostics of prestressed, concrete, bridge T-beams. A multi-point damage detection system is studied with use of numerically obtained data. The system is designed to detect the presence of the material discontinuities as well as their location.
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Modern control strategy of bidirectional DAB converter with consideration of control nonlinearity
PublikacjaThis paper focuses on the control strategy for modern universal bidirectional Dual Active Bridge (DAB) converters for microgrid systems. An analysis of the converter equations was carried out, and typical problems related to the influence of dead time on the system operation were discussed. A closed control loop was developed, then tested by simulation and on a laboratory stand.
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Study on applicability of two modal identification techniques in irrelevant cases
PublikacjaStudy on applicability of two modal identification techniques in irrelevant cases is made in this paper. The following techniques are considered: Peak Picking based on correlation analysis (PP-CA), dedicated for ambient vibrations and Eigensystem Realization Algorithm (ERA), formulated for free decay vibrations investigation. Irrelevant cases are found when analyzed signals are different than recommended to a given technique. The...
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Original footbridge in Mikolajki, Poland
PublikacjaIn summer 2016, a new footbridge in the town of Mikołajki (Poland) was built, over a stream connecting two adjacent lakes – Talty and Mikołajki. Its modern construction, based on the shape of a DN ice-boat, makes it inique in Poland, and probably in the world as well. This novel and dynamic shape became a significant landmark associated not only with Mikołajki, but also with the whole region of Mazury, as well as with sailing...
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Framework for Structural Health Monitoring of Steel Bridges by Computer Vision
PublikacjaThe monitoring of a structural condition of steel bridges is an important issue. Good condition of infrastructure facilities ensures the safety and economic well-being of society. At the same time, due to the continuous development, rising wealth of the society and socio-economic integration of countries, the number of infrastructural objects is growing. Therefore, there is a need to introduce an easy-to-use and relatively low-cost...
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Gate Driver with Overcurrent Protection Circuit for GaN Transistors
PublikacjaThe improvement of the gate driver for GaN transistor is presented in this paper. The proposed topology contains the overcurrent protectionwith the two-stage turning off and independent control of turn on and off time of the GaN transistor. The operation of driver and its application in thehalf-bridge converter are described using both simulation and prototype measurements. The overcurrent protection was tested in Double Pulse...
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Analysis of AC/DC/DC Converter Modules for Direct Current Fast-Charging Applications
PublikacjaThe paper is a comprehensive laboratory comparison study of two galvanic isolated solution off-board battery chargers: (1) Si-based cost-effective case, and (2) SiC-bidirectional ready for vehicle to grid concept case. All circuits are modular, and in both cases the DC/DC converter can be replaced according to the end user requirements (the coupled transformer remains the same and is constructed based on 12xC100 cores to avoid...
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O modelowaniu numerycznym dźwigarów zespolonych
PublikacjaThe paper is a general review of theoretical problems and corresponding numerical procedures actually available in commercial engineering software. Several possibilities of numerical simulation for composite girders are presented. Effectivity of meshing is showed on the simple example. Finally several examples of structural numeric models for real bridges are included. In the author's opinion, presented available procedures for...
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Wojciech Litwin dr hab. inż.
Osoby1992÷1996 – Studia na Wydziale Mechanicznym Politechniki Gdańskiej1996 – Zatrudniony na Wydziale Oceanotechniki i Okrętownictwa PG2004 – Obrona pracy doktorskiej2014 – obrona rozprawy habilitacyjnej2012 – obejmuje funkcję prodziekan ds. Nauki na Wydziale Oceanotechniki i OkrętownictwaUczestniczył w wielu projektach badawczych oraz pracach zleconych przez przemysł związanych z łożyskowaniem ślizgowym wałów głównych oraz niekonwencjonalnymi...
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Remote Monitoring System for Impedance Spectroscopy using Wireless Sensor Network
PublikacjaThe architecture of a miniaturized impedanceanalyser with wireless communication module for remoteImpedance Spectroscopy (IS) of anticorrosion coatings ondifficult-to-reach objects (e.g. on the steel construction ofthe bridge) is described in this paper. Some practical aspectsof implementation of a Wireless Sensor Network (WSN) arealso discussed. A low scale, middle range, WSN networkcomposed of a Base Station (BS) with a Personal...
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Damage-Involved Structural Pounding in Bridges under Seismic Excitation
PublikacjaDuring severe earthquakes, pounding between adjacent superstructure segments of highway elevated bridges was often observed. It is usually caused by the seismic wave propagation effect and may lead to significant damage. The aim of the present paper is to show the results of the numerical analysis focused on damage-involved pounding between neighbouring decks of an elevated bridge under seismic excitation. The analysis was carried...
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Dynamic Tests and Technical Monitoring of a Novel Sandwich Footbridge
PublikacjaA novel sandwich composite footbridge is described in this paper, for the first time after it has been put into operation over the Radunia River in the Pruszcz Gdański municipality. This paper presents results of dynamic tests and describes technical monitoring of the footbridge. The dynamic tests were conducted to estimate pedestrian comfort and were compared with the ones from numerical simulations made in the environment of...
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Informal employment in Poland: an empirical spatial analysis
PublikacjaThe main goal of our article is to bridge the gap in the regional analysis of informal employment in Poland and in particular to indicate the propensity for informal work in the working-age population, to test if informal activities are typical for marginalized people (less educated, unemployed, older) and to identify the regional and spatial heterogeneity in the propensity. We use data from the ‘Human Capital Balance 2010–2014’...
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BADANIA KOMPOZYTOWEGO MOSTU DLA PIESZYCH
PublikacjaThe paper presents in situ load testing of the innovative footbridge of FOBRIDGE grant mounted at Gdansk University of Technology. The span of composite sandwich structure (GFRP skins, PET core) and the scope of static and dynamic tests are presented. The selected, representative results of in situ measurements and data obtained from the SHM monitoring system are discussed. Besides the standard testing procedures on the full scale...