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Wyniki wyszukiwania dla: TRUSS BRIDGE
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Analysis of Failure Mechanism in Joints with Positive Eccentricity in CFS Truss
PublikacjaThe paper presents studies concerning the load-bearing capacity of truss joints with a positive eccentricity resulting from the arrangement of geometric members and the failure mechanisms observed in the joints. Based on the previously conducted experimental study, a numerical model of the tested fragment of the CFS truss with eccentricity in the joint was created and validated. All structural details of the tested truss and the...
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PROBABILISTIC ANALYSIS OF A SPACE TRUSS BY MEANS OF A MULTIDIMENSIONAL VARIABLE DESCRIPTION
PublikacjaThe objective of this paper is to present a variant of the point estimate method (PEM) to determine mean values and standard deviations of limit loads of engineering structures. This approach is illustrated by limit state analysis of a space truss, considering geometric and material imperfections. The calculations were performed for different random models, so the influence of random parameters on the limit load of the truss can...
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Preliminary experimental research on stability of truss' joint with positive eccentricity
PublikacjaRecently, a very large interest in lightweight steel structures made from cold-formed sections has been noticeable. In the design practice, a large emphasis is put on rational shaping of both the thin-walled elements and constructions designed on them. The aim of this paper is to present the methodology for preparation of experimental research that model the behaviour of members in trusses made of cold-formed sections with positive...
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A dynamic vehicle-bridge model based on the modal identification results of an existing EN57 train and bridge spans with non-ballasted tracks
PublikacjaThis paper addresses the methodology of the bridge-vehicle dynamic model definition based on the free response measurements of an existing train and existing bridge spans. In the case of the railway vehicle, the methodology uses the impulse excitations of a single car by means of the wedge method. In the case of the bridge spans, free responses are collected after the passages of trains. The global modal parameters (frequencies...
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Trust and Distrust in e-Democracy
PublikacjaIn the digital government research literature, the concept of trust is typically used as a precondition for the adoption of digital technology in the public sector or an outcome of a roadmap leading up to such adoption. The concept plays a central role in many decisions linked to the planning, adoption and management of the public sector technology. In contrast, the concept of...
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An approach for evaluating trust in it infrastructures
PublikacjaW artykule zademonstrowano metodę oceny poziomu zaufania do systemu TI w oparciu o podejście funkcji przekonania.
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A Framework for Analyzing Trust in IT Systems.
PublikacjaProblem uzasadnienia zaufania do systemów realizowanych w technologiach informacyjnych nabiera coraz większego znaczenia wraz z poszerzaniem zakresu zastosowań takich systemów. W artykule wprowadzono koncepcje 'dowodu zaufania', który stanowi strukturę zawierająca cały materiał dowodowy wraz ze stowarzyszona z nim argumentacja uzasadniająca, ze system jest wystarczająco wiarygodny (w sensie bezpieczeństwa, zabezpieczenia, prywatności...
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Reasoning about trust in IT infrastructures
PublikacjaW artykule zaprezentowano metodę pozwalającą na ilościowe określenie poziomu zaufania do systemu TI.
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Trust and Distrust in e-Democracy
PublikacjaIn the digital government research literature, the concept of trust is typically used as a precondition for the adoption of digital technology in the public sector or an outcome of a roadmap leading up to such adoption. The concept plays a central role in many decisions linked to the planning, adoption and management of the public sector technology. In contrast, the concept of distrust is almost neglected in such literature but,...
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An Approach to Trust Case Development
PublikacjaIn the paper we present an approach to the architectural trust case development for DRIVE, the IT infrastructure supporting the processes of drugs distribution and application. The objectives of DRIVE included safer and cheaper drugs distribution and application. A trust case represents an argument supporting the trustworthiness of the system. It is decomposed into claims that postulate some trust related properties. Claims differ...
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Test loading of the longest span arch bridge in Poland
PublikacjaBridge structures undergo thorough examination during test loading before they come into use. The aim of the examination is to check the correctness of the working structure and construction design assumptions. Test loading on the bridge is preceded by examination specification. This paper describes computational model and test loading results carried out during examibation of the bridge over the Vistula within the bypass of Puławy...
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Control strategy for the multilevel cascaded H-bridge converter
PublikacjaThe paper presents the control strategy for Cascaded H-bridge (CHB) converter . The converter output voltage using Space-Vector Pulse Width Modulation (SV-PWM) strategy is controlled. The DC-link voltages are controlled by appropriate choice of H-Bridges and appropriate choice of active and passive vectors.
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The bridge over Regalia River in Szczecin - design and construction.
PublikacjaNowoclowa Route is the largest projekt in Szczecin, that consists of 11 km of roads 3,3 km bridges and viaducts, including three parallel bridges across Regalica River (the east arm of Odra River), 535 m long, with the spans: 59+90+90+116+116+64m. The bridge structure consist of two steel plate girders composite with reinforced concrete deck slab. The design and the construction of the bridge are described in the paper.
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Theory of systems & cybernetics as a bridge between theory and practice. .
PublikacjaW pracy przedstawiono sposoby posługiwania się Teorią Systemów i Cybernetyką celem identyfikacji efektu synergii między nauką i działalnością praktyczną.
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Diagnostics and monitoring of the longest span extradosed bridge in Europe
PublikacjaThe article presents complex diagnostic procedures applied for the purpose of behavior analysis of the extradosed bridge with the longest span in Europe that was built in 2018 in Poland. The system of health monitoring was used to: register internal forces in temporary supports, monitor concrete bonding, perform in situ diagnostics and operation tests. The bridge is a continuous four-span structure with spans theoretical lengths...
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Stress analysis of the bridge hangers in terms of the fatigue verification
PublikacjaThe paper presents the results of numerical stress analysis of the bridge rod hangers. Two types of hangers were taken into account, i.e. the bolted hanger and the welded hanger. A detailed FEM shell models of the connection area between the hanger and the bridge span have been developed. Local stress concentration effects have been investigated in terms of fatigue verification.
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Stability of truss with side - supports. The case of linear and rotational elastic supports
PublikacjaThe research is devoted to study lateral buckling of truss with linear and rotational elastic side-supports. Geometrically nonlinear analysis of example truss with linear and rotational elastic sidesupports is carried out. The limit normal force in compressed chord of the truss due to stiffness of side supports is calculated. The elastic support reaction in relation to force in compressed chordand coefficient of buckling length...
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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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Test loadings of arch bridges
PublikacjaIn Poland an appreciable developement of bridge building can be seen in recent years. Arch structures are more and more common, because of the original geometrical and aesthetical form, aside with explicit structural system. Paper concerns the applied computational conceptions and researches on an example of two arch bridges. The goal of the studies is to check the correctness of the real construction work and design assumptions,...
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Trust Dynamics Analysis of CTR Scheme Subversion under Virtual Anonymity and Trust-Unaware Partner Selection
PublikacjaWe propose a framework to study Markovian trust value dynamics in a centralized Computational Trust and Reputation (CTR) scheme under trust-unaware partner selection using a mean-value approximation. Analytically founded answers are sought to questions like: Can dishonest agents subvert the CTR scheme (i.e., acquire higher trust values than honest agents)? Is indirect reciprocity incentivized? Is there a qualitative impact of a...
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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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DISPLACEMENT MEASUREMENTS DURING LOAD TESTING OF THE RAILWAY ARCH BRIDGE
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Limit States of Shallow Bridge Foundations With Sheet Piling Covers
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Ultrasonic diagnostics of concrete T-beams used in bridge structures
PublikacjaThis paper describes a method of ultrasonic diagnostics used for prefabricated concrete elements. The studies are focused on the applicability of nondestructive techniques based on impulse and wave packet induced elastic waves for the condition assessment of T-shaped bridge beams. Experimental tests were performed for the prestressed beam used for the superstructure of the viaduct on A1 highway near Toruń. In addition numerical...
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Application of guided wave propagation in diagnostics of steel bridge components
PublikacjaEarly detection of potential defects and identification of their location are necessary to ensure safe, reliable and long-term use of engineering structures. Non-destructive diagnostic tests based on guided wave propagation are becoming more popular because of the possibility to inspect large areas during a single measurement with a small number of sensors. The aim of this study is the application of guided wave propagation in...
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DC-link voltage balancing in cascaded H-Bridge converters
PublikacjaIn the paper a DC-link voltage balancing strategy for multilevel Cascaded H-Bridge (CHB) converter is proposed. Presented solution bases on optimal choice of active vector durations in Space-Vector Pulse Width Modulation (SV-PWM). It makes it possible to DC-link voltages control and to properly generate the output voltage vector in the case of DC-link voltage unbalance. Results of simulation and experimental researches...
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Numerical Simulation of Open Channel Flow between Bridge Piers
PublikacjaPrzedstawiono dwuwymiarowy model przepływu wody płytkiej, który wykorzystano do symulacji przepływu wody w kanale otwartym w rejonie przekroju mostowego. Równania przepływu rozwiązano metodą objętości skończonych. Wyniki symulacji ruchu wody pomiędzy filarami mostowymi porównano z pomiarami laboratoryjnymi przeprowadzonymi w Laboratorium Hydrauliki i Inżynierii Środowiska politechniki Gdańskiej. Zgodność uzyskanych wyników obliczeń...
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The roadway bridge over Vistula River in Plock - design and construction.
PublikacjaThe paper presents the design and construction works of the Roadway Bridge over Vistula River in Plock (Poland), designed by first two paper authors as being the winners of international competition for design oraganized by Polish association of the bridge engineers. Total length of the bridge is 1,200 m; 615 m is the length of main bridge part over the Vistula riverbed, and 585 m is the length of access bridge part over river...
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Damage of a post-tensioned concrete bridge – Unwanted cracks of the girders
PublikacjaThe cracking of a post-tensioned T-beam superstructure, which was built using the incremental launching method, is analyzed in the paper. The problem is studied in detail, as specific damage was observed in the form of longitudinal cracks, especially in the mid-height zone of the girder at the interface of two assembly sections. The paper is a case study. A detailed inspection is done and non-destructive testing results of the...
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Concrete-filled FRP tubular members in marine and bridge structures
PublikacjaConcrete core of the concrete-filled tubes (CFTs) with circular cross-section is in the case of an axial compression subjected to a spatial state of compressive stresses. This state leads to enhancement in the concrete strength. The enhancement is utilized in Eurocode 4 design procedures for CFSTs (i.e. CFTs with tube made of steel). The structural design of CFFTs (i.e. CFTs with tube made of Fibre Reinforced Polymer - FRP) is...
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A New Geodetic Method of Examination of Geometrical Conditions of a Crane Bridge
PublikacjaSafety is one of the key aspects related to crane-based material transport. In order to ensure safe crane operation and material transport, it is necessary to meet certain geometrical conditions. The authors addressed the geometrical conditions of a crane bridge, a substantial crane component. The paper presents the method to compute displacement components of points on the top of a bridge crane relative to their design position....
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Seismic Pounding Between Bridge Segments: A State-of-the-Art Review
PublikacjaEarthquake-induced structural pounding in bridge structures has been observed in several previous seismic events. Collisions occur at the expansion joints provided between adjacent decks or between the deck and abutment. Pounding between the structural elements may lead to severe damages and even to the unseating of the bridge in certain cases. Several investigations have been performed to study pounding in bridges under uniform...
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Earthquake-induced pounding between superstructure segments of isolated bridge
PublikacjaThe use of seismic isolation in bridges is considered as one of the most promising advanced technologies to enhance the structural safety during earthquakes. However, the method results in larger displacements of superstructure segments increasing the probability of pounding between them. Reports after severe ground motions show that the earthquake-induced structural pounding may lead to significant damage in isolated bridges....
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Dynamics of the small-span railway bridge under moving loads
PublikacjaThe paper presents the results of dynamic analysis of the small-span railway bridge, subjected to an action of moving trains. Numerical simulations were performed using three different load models: series of moving forces, series of moving single-mass and double-mass oscillators. The parameters of the vehicle were taken from the existing EN57 train. The parameters of the bridge were taken from the existing steel span of 10,24 m...
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Dynamic analysis of the railway bridge span under moving loads
PublikacjaThe first part of this paper provides a review of the state of knowledge of the dynamic behaviour of railway bridges under moving loads. Particular attention is paid to developments in modelling railway bridge loading and dynamic vehicle-span (structure) interaction. The most important aspects determining the advancements in this area of knowledge are identified. The contemporary techniques for defining bridge span finite element...
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Conjugated control of triple active bridge converter with common HFT
PublikacjaPaper presents synthetic analyses of single input, dual output DC/AC/DC converter with common high frequency transformer. Rise the problem of cross-coupling power flows between secondary terminals, under asymmetrical control operating condition. It also proposes a new approach to converter control, based on conjugated phase shift modulation and defines its limitations. Finally, the developed control technique was verified by simulation...
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Power electronic transformer based on cascaded H-bridge converter
PublikacjaIn this paper the control strategy of power electronic transformer (PET) is proposed. The analyzed structure of PET uses two seven-level cascaded H-bridge (CHB) rectifiers. The electrical power of PET is transferred between DC-links of CHB converters using dual-active-bridges (DABs) and low voltage high frequency transformers. The roposed solution allows for controlling the active and reactive power with a low level of harmonic...
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Monitoring of concrete curing in extradosed bridge supported by numerical simulation
PublikacjaThe paper describes a mathematical model of concrete curing taking into account kinetics of setting reactions. The numerical model is implemented in the author’s program that was used to monitor thermal effects recorded in the concrete bottom plate of the extradosed bridge. Numerical approach was verified by experimental measurements and used for assessment of the current compressive strength due to degree of hydration of fresh...
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Displacement measurements during load testing of railway arch bridge
PublikacjaThe paper discusses issues concerning load tests carried out on a twin-track, arch railway bridge over the Martwa Wisla river in Gdansk. Currently, it is the bridge with the longest span in its class in Poland. The load-bearing structure consists of three no-hinge arches and an orthotropic deck suspended from them. The studies of the structure assumed the performing of static and dynamic tests. The paper presents the method for...
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Launching of steel bridge girder. Application of nonlinear shell models
PublikacjaThe paper describes the final technology of launching the steel bridge superstructure. The original technology failed in the first construction stage. Local damage of steel webs caused by plastic buckling stopped the procedure. In the effect of damage a new consulting team was employed to solve the problem and redesign a technology of constructing. The key element of the new solution was developed with great help of non-linear...
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Numerical analysis and in situ tests of the Grot Rowecki Bridge in Warsaw
PublikacjaThe paper presents the FEM analysis of the reconstructed the Grot-Rowecki Bridge over Vistula river in Warsaw. The bridge has seven spans and consists of two independent structures with the longest spans of 120 m. After reconstruction the bridge is over 10 m wider. The numerical, nonlinear analysis has been con-ducted on a global and local FEM models. These models are defined so as they strictly comply with global structural bridge...
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Argument strategies and patterns of the Trust-IT framework
PublikacjaArtykuł dotyczy metodologicznego i narzędziowego środowiska Trust-IT wspierającego budowę dowodów zaufania (ang. trust case), a w szczególności strategii tworzenia dowodu zaufania. Strategia uzależniona jest od właściwości systemu (lub innego rozważanego obiektu), która podlega analizie w ramach dowodu zaufania. W artykule zaprezentowano dwie strategie: oparta na ryzyku i oparta na standardach oraz omówiono kilka często stosowanych...
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An approach to evaluation of arguments in trust cases
PublikacjaTrustworthiness of IT systems can be justified using the concept of a trust case. A trust case is an argument structure which encompasses justification and evidence supporting claimed properties of a system. It represents explicitly an expert's way of assessing that a certain object has certain properties. Trust cases can be developed collaboratively on the basis of evidence and justification of varying quality. They can be complex...
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Combinning technologies to achieve decisional trust
PublikacjaW pracy zaproponowano modelowe podejście do problemu doboru i złożenia technologii informatycznych w celu osiągnięcia wysokiego poziomu zaufania w procesie podejmowania decyji.
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Relations between law, authority, and trust
PublikacjaW artykule przedstawiono relacje pomiędzy prawem, autorytetem i zaufaniem. Zwrócono uwagę, że prawo, a głównie jego egzekwowanie wynika z przymusu państwowego. Pozostałe natomiast kategorie są kształtowane przez inne czynniki. Rozważania mają charakter filozoficzny.
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Dis/Trust and data-driven technologies
PublikacjaThis concept paper contextualises, defines, and systematises the concepts of trust and distrust (and their interrelations), providing a critical review of existing literature so as to identify gaps, disjuncture, and continuities in the use of these concepts across the social sciences and in the context of the consolidation of the digital society. Firstly, the development of the concept of trust is explored by looking at its use...
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Trust case - a case for trustworthiness of IT infrastructures
PublikacjaArtykuł prezentuje podejście do budowy argumentów (trust case) uzasadniających zaufanie do systemów i infrastruktur IT. Wprowadza system pojęć związanych ze strukturą i treścią trust case, identyfikuje udziałowców trust case oraz dyskutuje możliwość wsparcia narzędziowego procesu zarządzanie trust case. Omawia równiez krótko dotychczasowe zastosowania tego podejścia.
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Trust triggers and barriers in intercultural teams
PublikacjaIntercultural teams are more and more popular nowadays — they constitute a serious challenge in terms of effective cooperation and trust building, however. The article presents the potential problems that can affect intercultural cooperation and stresses the power of trust in cultural diversity conditions. The ten-factor model of intercultural team trust is presented. The main aim was to answer the questions: what are the differences...
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Some remarks about numerical stability in nonlinear dynamics on the basic of truss structures.
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Reliability assessment of truss towers using Monte Carlo Method, PEM and RSM
PublikacjaThe paper discusses the reliability assessment of simple random truss structures using three different probabilistic methodologies: the Monte Carlo method, the Point Estimate Method and the Response Surface Method. A benchmark truss structure example is analyzed. A set of numerical calculations of critical load is performed and the results are taken as the basis of advanced probabilistic calculations. Using the samples, numerical...