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Search results for: BRIDGE FAILURE
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Investigation of stability and limit load of a truss overhead opened bridge
PublicationThe paper presents selected methods of determining stability and limit load of a truss top chord in opened bridges. These methods include linear buckling and non-linear static analysis based on the finite element method and algorithms based on design code procedures. The described methods were tested on an example of a steel footbridge situated in Straszyn. The results of stability analysis are compared. The results of geometrical...
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Monitoring of concrete curing in extradosed bridge supported by numerical simulation
PublicationThe 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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DC-link voltage balancing in cascaded H-Bridge converters
PublicationIn 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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Application of guided wave propagation in diagnostics of steel bridge components
PublicationEarly 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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Numerical Simulation of Open Channel Flow between Bridge Piers
PublicationPrzedstawiono 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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Displacement measurements during load testing of railway arch bridge
PublicationThe 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
PublicationThe 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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Damage of a post-tensioned concrete bridge – Unwanted cracks of the girders
PublicationThe 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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Power electronic transformer based on cascaded H-bridge converter
PublicationIn 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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A New Geodetic Method of Examination of Geometrical Conditions of a Crane Bridge
PublicationSafety 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
PublicationEarthquake-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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Dynamics of the small-span railway bridge under moving loads
PublicationThe 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
PublicationThe 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
PublicationPaper 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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Concrete-filled FRP tubular members in marine and bridge structures
PublicationConcrete 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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The roadway bridge over Vistula River in Plock - design and construction.
PublicationThe 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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Assessing ecotoxicity and the endocrine potential of selected phthalates, BADGE and BFDGE derivatives in relation to environmentally detectable levels
PublicationThere is no doubt that the subject area of plasticmaterials (e.g., production of epoxy resins or polyesters) is inherently connected to issues concerning bisphenol A (BPA) and its analogues. Unfortunately, much less attention has been given to other compounds, which are also used for the production of these materials. Bisphenol A diglycidyl ether (BADGE) is a synthetic industrial compound obtained by a condensation reaction between...
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Reducing the Probability of Failure in Manufacturing Equipment by Quantitative FTA Analysis
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Experimental study on ultrasonic monitoring of splitting failure in reinforced concrete
PublicationThis paper investigates inspection of reinforced concrete elements sensitive to the splitting failure. The behaviour of a reinforced concrete specimen subjected to a tensile stress is considered. The damage detection procedure is based on the ultrasonic wave propagation technique. The piezoelectric transducers are located on both ends of the specimen and the measurements are taken periodically during the incrementally increased...
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Impact of WDM Network Topology Characteristics on the Extent of Failure Losses
PublicationW artykule dokonano oceny wpływu charakterystyk topologicznych sieci na rozmiar strat po awarii węzła/łącza będącej następstwem ataku. W tym celu wprowadzono współczynnik ATRF. Wyniki badań pokazały, że wykorzystanie standardowej metryki odległości do wyznaczania tras podstawowych prowadzi do istotnego zwiększenia liczby połączeń uszkodzonych w wyniku ataku w porównaniu ze skutkami awarii losowej.
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Failure analysis of the exhaust valve face in diesel marine engine
PublicationThe exhaust valve from marine diesel engine which was damaged after 2000 hours of service was investigated. In order to prolong the service time the valve face was cladded with cobalt base alloy using laser technique. After failure microstructural and chemical analyses reviled that cladding process was conducted improperly. The chemical composition of the clad layer was far from the designed one and what more completely inhomogeneous....
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Excavation induced cast iron pipeline failure – a numerical study
PublicationNumerical study on impact of an unsecured excavation on an underground pipeline. Analysis focused on investigation of pipeline displacement generated by soil movement caused by excavation and heavy traffic. Numerical calculations and soil parameter sensitivity analysis based on Finite Element Method. Some comparisons of results with real-life failure cases.
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FAILURE OF MAGNETIC FLUID SEALS OPERATING IN WATER: PRELIMINARY CONCLUSIONS
PublicationThe article analyses properties of magnetic fluid seals installed in rotary sealing no des which operate in the utility water environment. Seals of this type have been examined as a possible solution to the problem with ship manoeuvring propulsion sealing. The present analysis bases on laboratory durability tests of magnetic fluid seals expo sed to long - term utility water loads, at different water pressures and shaft revolutions....
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Analysis of Failure Mechanism in Joints with Positive Eccentricity in CFS Truss
PublicationThe 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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Assessment of unusual failure in crankshaft of heavy-duty truck engine
PublicationThe unusual premature failure of a heavy-duty truck engine crankshaft has been the subject of a rigorous study, and this manuscript describes it in detail. The failure was happened to begin with the growth of the crack from the surface defects, in the form of the clusters of non-metallic inclusions, in the lubrication hole zone of the first main journal, which was the stress concentration zone. A series of experiments including...
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Fundamental Schemes to Determine Disjoint Paths for Multiple Failure Scenarios
PublicationDisjoint path routing approaches can be used to cope with multiple failure scenarios. This can be achieved using a set of k (k> 2) link- (or node-) disjoint path pairs (in single-cost and multi-cost networks). Alternatively, if Shared Risk Link Groups (SRLGs) information is available, the calculation of an SRLG-disjoint path pair (or of a set of such paths) can protect a connection against the joint failure of the set of links...
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Zniszczenie korozyjne wymiennika ciepła = Corrosion failure of a heat exchanger
PublicationPłytowy wymiennik ciepła ze stali 316L uległ zniszczeniu po trzech latach eksploatacji, wskutek perforacji po czyszczeniu nieodpowiednim środkiem czyszczącym.
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The PARAGON Heart Failure trial – ongoing investigation of the angiotensin receptor antagonist/neprilysin inhibitor sacubitril/valsartan in heart failure patients with hypertension and preserved ejection fraction
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Arch bridges under test loadings
PublicationThis 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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Building Bridges Between Medicine and Sociology
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Bridges to Independence / Mosty ku niepodległości
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A concept of an application to plan the time lines of building selected bridge structures
PublicationW rozdziale został przedstawiony przykład autorskiego programu komputerowego przeznaczonego do planowania czasu pracy i kosztów w budownictwie mostowym. Zaletą programu jest możliwość przedstawienia wyników w formie graficznej w sposób deterministyczny i niedeterministyczny. Ma to ogromne znaczenie jeżeli poszukujemy optymalnych rozwiązań dotyczących zagadnień ryzyka i ekonomiki budownictwa.
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Deltorphin analogs restricted via a urea bridge: structure and opioid activity
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Deltorphin analogs restricted via a urea bridge: structure and opioid activity
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Displacements of Cable-Stayed Bridge Measured With The Use of Traditional And Modern Techniques
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"FEM Parametric Study on Ultimate Bearing Capacity of CFST Arch Bridge
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Reference FEM model for SHM system of cable-stayed bridge in Rzeszów
PublicationThe paper presents the references model for structural health monitoring system (SHM) of cable-stayed bridge recently constructed in Rzeszów over Wisłok River. The SHM system is design to provide on-line information on the structure state and facilitate its maintenance procedures. The main feature of the SHM system is permanent observation of the dynamic behavior of the bridge with focus on cable vibrations. The paper discusses...
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Historical crane on the redesigned original trestle bridge as a memorial of Gdansk Shipyard
PublicationThe paper includes selected aspects of the study, whose goal is to hold the historical crane 642-24 in its current location after the modification of trestle bridge static scheme. The scope of the paper includes the assessment of current technical condition of the object, a presentation of FEM analyses, a description of the assumed load cases, results of the static calculations, checking the effort of construction elements, global...
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Theoretical analysis of the cable-stayed bridge over brda river in Bydgoszcz
PublicationThe topic of this article is the numerical analysis carried out for the cable-stayed tram (road) bridge over Brda river in Bydgoszcz. The goal of numerical studies was the verification of project assumptions and construction solutions elaborated by the autonomous team. The bridge calculations were conducted on three independent FEM models The internal forces and the elements effort under different loading schemes were examined....
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Pylon foundation of a cable stayed bridge at the motorway ring road of Wrocław
PublicationThe largest bridge of the motorway ring road of Wroclaw is a cable stayed bridge over the Odra river near Rędzin. Due to hydrogeological conditions of the ground it was not convenient to use standard bored piles of high length. Instead shorter piles were applied with additional improvement by cement injections at the pile toes. This decision was possible by extending ground investigation program and application of numerical modeling...
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Retrofit analysis of florida beam-and-post reinforced concreta bridge barriers
PublicationTematem pracy jest analiza przebiegu kolizji drogowych w przypadku najechania rozpędzonego pojazdu na betonową barierę mostową typu "Florida beam-and-post". Przedstawiono podstawy konstruowania modelu obliczeniowego do komputerowej symulacji zderzenia przy wykorzystaniu systemu LS-Dyna. Na podstawie otrzymanych wyników sformułowano zalecenia ewentualnych modyfikacji istniejących barier w celu poprawienia ich własności.
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Influence of Actual Curing Conditions on Mechanical Properties of Concrete in Bridge Superstructures
PublicationThis article presents the research on the mechanical characteristics of concrete in the construction of three concrete bridges. A system of recording the internal temperature of concrete and automatic control of laboratory ovens was used for specimen curing. This allowed the specimens to be cured under conditions similar to those occurring in the structure. Before the construction, reference blocks were used to define similar curing...
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Numerical Simulation of two dimensional flow past a bridge cross section
PublicationThis work presents some numerical results concerning application of CFD in civil engineering problems. Selected theoretical aspects of fluid mechanics are elucidated. In the second part of the paper a cross section of upper footbridge of the Bella Sky Hotel in Copenhagen is analysed numerically in the field of wind action.
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Probabilistic analysis of settlements under a pile foundation of a road bridge pylon
PublicationThe paper addresses the reliability change of a road bridge pile foundation due to the unpredictable increase of settlements in time. The analysis is based on the Rędziński Bridge in Wrocław, Poland, its design assumptions, and monitoring results. The bridge foundation rests on a multi-layered subsoil assumed random. The Finite Element model of the subgrade is generated in ZSoil® software. To simplify the probabilistic approach,...
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Prefabricated structures under earthquake excitation: damage and failure of connection joints
PublicationCelem artykułu jest analiza zachowania się złączy pomiędzy elementami belkowymi a słupami w konstrukcjach prefabrykowanych poddanych obciążeniom dynamicznym powstającym podczas trzęsień ziemi. Wyniki przedstawione w pracy, uzyskane na podstawie badań numerycznych przeprowadzonych dla wybranego modelu konstrukcji, pokazują, iż złącza są najsłabszym elementem wymagającym zwrócenia szczególnej uwagi przy projektowaniu konstrukcji...
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Sympathetic Activation in Chronic Heart Failure: Potential Benefits of Interventional Therapies
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Enhanced Sympathetic and Ventilatory Responses to Central Chemoreflex Activation in Heart Failure
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Predictive Factors of Late Venous Aortocoronary Graft Failure: Ultrastructural Studies
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Acute renal failure due to leptospirosis. Diagnostic challenges – a case report
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Failure model of main elements of the ship engine crankshaft-piston assembly
PublicationThe paper presents a failure model of main elements of the crankshaft-piston assembly, based on failures ofcrankshaft-piston assembly and timing gear system of the Sulzer RD engines, retrieved from the equipment reliabilitydata of selected ships.