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Search results for: CONCRETE DAMAGE PLASTICITY (CDP)
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FE-modelling of strain localization in concrete with coupled elasto-plasticity and damage
PublicationW artykule przedstawiono wyniki numerycznej dla zginania belki betonowej przy zastosowaniu modelu sprężysto-plastycznego, modelu z degradacja sztywności i modelu połączonego sprężysto-plastycznego z degradacją sztywności. Wszystkie modele rozszerzono o długość charakterystyczną mikrostruktury za pomocą teorii nielokalnej.
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FE analysis of strain localization in concrete in elasto-plasticity and damage mechanics with non-local softening
PublicationW artykule przedstawiono wyniki symulacji numerycznych zjawiska lokalizacji odkształceń w betonie wykonanaych przy zastosowaniu metody elementów skończonych (MES). Do opisu betonu wykorzystano dwa prawa materiałowe zdefiniowane w ramach teorii plastyczności (kryterium Druckera-Pragera w ściskaniu i warunek Rankine'a w rozciąganiu) oraz mechaniki uszkodzeń w sformułowaniu odkształceniowym. Dla poprawnego opisu lokalizacji (regularyzacji...
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Simulations of spacing of localized zones in reinforced concrete beams using elasto-plasticity and damage mechanics with non-local softening
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Simulations of spacing of localized zones in reinforced concrete beams using elastic-plasticity and damage mechanics with non-local softening
PublicationArtykuł omawia obliczanie belek żelbetowych z uwzględnieniem lokalizacji odkształceń. Obliczenia wykonano przy zastosowaniu MES na bazie sprężysto-plastycznego prawa konstytutywnego i modelu zniszczeniowego uwzględniającego degradację sztywności rozszerzonego o długość charakterystyczną mikrostruktury za pomocą teorii nielokalnej.
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Damage Analysis of Tensioning Cable Anchorage Zone of a Bridge Superstructure, Using CDP Abaqus Material Model
PublicationNumerical analysis of the tensioning cables anchorage zone of a bridge superstructure is presented in this paper. It aims to identify why severe concrete cracking occurs during the tensioning process in the vicinity of anchor heads. In order to simulate the tensioning, among others, a so-called local numerical model of a section of the bridge superstructure was created in the Abaqus Finite Element Method (FEM) environment. The...
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Performance of isotropic constitutive laws in simulating failure mechanisms in scaled RC beams
PublicationResults of numerical calculations of reinforced concrete (RC) beams are presented. Based on experimental results on longitudinally reinforced specimens of different sizes and shapes are investigated. Four different continuum constitutive laws with isotropic softening are used: one defined within continuum damage mechanics, an elasto-plastic with the Rankine criterion in tension and the Drucker-Prager criterion in compression, a...
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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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Projektowanie budynków użyteczności publicznej narażonych na ataki terrorystyczne z wykorzystaniem systemu ochrony pasywnej
PublicationW artykule przedstawiono projektowanie systemów ochrony pasywnej w budynkach użyteczności publicznej, które mogą posłużyć jako przykład i stanowić podstawę do dalszych założeń przy projektowaniu budynków narażonych na obciążenie wybuchem spowodowanym przez ataki terrorystyczne. W pracy przeprowadzono symulacje numeryczne na przykładzie ściany budynku użyteczności publicznej wykonanego w technologii żelbetowej. Obliczenia wykonano...
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Experimental-Numerical Analysis of the Effect of Bar Diameter on Bond in Pull-Out Test
PublicationBar diameter is one of the basic factors affecting bond behavior, which is still of interest due to opposing opinions regarding its effect on bond behavior in the pull-out test. This paper presents an experimental and numerical bond analysis of ribbed reinforcing bar in concrete. The aim was to experimentally evaluate the effect of bar diameter on the bond behavior in the pull-out test and to perform numerical simulations of the...
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Limits of enhanced of macro- and meso-scale continuum models for studying size effect in concrete under tension
PublicationThe paper investigates a mechanical quasi-static size effect in concrete during splitting tension at the macro- and meso-level. In experiments, five different diameters of cylindrical concrete specimens were tested. Twodimensional plane strain finite element (FE) simulations were carried out to reproduce the experimental size effect. The size effect in experiments by Carmona et al. was also simulated. Two enhanced continuum concrete...
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A constitutive law for concrete with smooth transition from continuous into discontinuous cracks’ description
PublicationPaper presents a constitutive model for concrete that combines a continuous and discontinuous crack’s description to simulate the concrete under tensile dominated loads. In a continuum regime, two different constitutive laws were used. First, a plasticity model with the Rankine failure criterion and an associated flow rule was used. Second, a constitutive law based on isotropic damage mechanics was formulated. Both model alternatives...
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A coupled constitutive model for fracture in plain concrete based on continuum theory with non-local softening and eXtended Finite Element Method
PublicationThe paper presents a constitutive model for concrete which combines a continuous and discontinuous fracture description. In a continuum regime, two different constitutive laws were used. First, a plasticity model with a Rankine failure criterion and an associated fl ow rule was used. Second, a constitutive law based on isotropic damage mechanics was formulated. In order to capture the width of a localized zone and to obtain mesh-independent...
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Ultrasound monitoring for evaluation of damage in reinforced concrete
PublicationThe paper deals with automated monitoring of damage evolution in concrete elements subjected to three-point bending tests. The monitoring is based on the nonlinear interactions of traveling ultrasonic waves with micro-crack zones inside the concrete specimens and surface-breaking cracks. The developed procedure assumes semi-continuous ultrasonic testing during the element full loading cycle and generation of the power spectral...
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Causes of damage and methods of repairing floor made on polystyrene concrete
PublicationThe paper describes damages, tests and repair of the floor made on existing ceiling and expanded polystyrene concrete underlay. The floor was built on a reinforced concrete ceiling with an area of about 1050 m2. Significant damage in the form of cracks, detachments and unevenness was found in the floor. In order to determine the causes of damage, in situ tests and laboratory tests were carried out. It was found that the damage...
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SIGNIFICANT GUIDELINE FOR THE DAMAGE INDICES APPLIED TO REINFORCED CONCRETE STRUCTURES
PublicationIn this paper, based on a deep overview and literature study, the different formulas proposed for damage indices (DIs) applied to reinforced concrete structures under monotonic or cyclic loading are classified and presented. The DIs are applied to quantify the damages to structures, ranging from zero to one. Normally, they are applied to make a decision for repairing or demolition of the structures in the post-earthquake phases. Keywords:...
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RMS-based damage detection in reinforced concrete beams: numerical simulations
PublicationImage-based damage detection methods using guided waves are well known and widely applied approaches in structural diagnostics. They are usually utilized in detection of surface damages or defects of plate-like structures. The article presents results of the study of applicability of imaging wave-based methods in detection in miniscule internal damage in the form of debonding. The investigations were carried out on numerical models...
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Thermodynamically consistent gradient theory of damage coupled with gradient plasticity
PublicationPrzedstawiono termodynamicznie zgodną teorię plastycznego zniszczenia w zakresie mechaniki Newtona-Eshelbego. Poza klasycznymi równaniami ruchu w przestrzeni fizycznej sformułowano dynamiczne równania równowagi sił powiązanych z defektami w przestrzeni materialnej oraz pierwsze i drugie prawo termodynamiki w przestrzeni fizycznej i materialnej. Ogólne równania konstytutywne przyjęto jako funkcję gradientu deformacji, jego składników...
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Numerical modeling of GPR field in damage detection of a reinforced concrete footbridge
PublicationThe paper presents a study on the use of the ground penetrating radar (GPR) method in diagnostics of a footbridge. It contains experimental investigations and numerical analyses of the electromagnetic field propagation using the finite difference time domain method (FDTD). The object of research was a reinforced concrete footbridge over a railway line. The calculations of the GPR field propagation were performed on a selected cross-section...
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Evaluation of pounding effects between reinforced concrete frames subjected to far-field earthquakes in terms of damage index
PublicationIn this paper, three different damage indexes were used to detect nonlinear damages in two adjacent Reinforced Concrete (RC) structures considering pounding effects. 2-, 4- and 8-story benchmark RC Moment Resisting Frames (MRFs) were selected for this purpose with 60%, 75%, and 100% of minimum separation distance and also without any in-between separation gap. These structures were analyzed using the incremental dynamic analysis...
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RMS-based damage identification in adhesive joint between concrete beam and steel plate using ultrasonic guided waves
PublicationAdhesive joints have numerous applications in many branches of industry, such as civil engineering, automotive, aerospace and shipbuilding. As with most structural elements, adhesive joints can experience any damage mechanism, which induces the need for diagnostic testing. Ultrasonic waves are widely used for non-destructive inspection of many structures and their elements, including adhesive joints. Guided wave propagation method...
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Weakly non-local theories of damage and plasticity based on balance of dissipative material forces
PublicationWykazano, że założenie o siłach materialnych oraz odpowiadających im równaniach równowagi w połączeniu z klasycznymi prawami dynamiki w przestrzeni fizycznej, pozwoliło na sformułowanie teoretycznych podstaw w zakresie słabo-nielokalnych gradientowych modeli zniszczenia i plastyczności. Odpowiednie równania równowagi w przestrzeni fizycznej i materialnej oraz pierwsze i drugie prawo termodynamiki zapisano w postaci całkowej. Następnie...
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Damage Detection of Steel-Concrete Composite Beam
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Modelling of concrete behaviour with a non-local continuum damage approach
PublicationW artykule przedstawiono wyniki numerycznej dla różnych problemów brzegowych związanych z powstawaniem rys w betonie. Obliczenia wykonano przy zastosowaniu modelu zniszczeniowego (z uwzględnieniem degradacji sztywności). Do opisu rys, model rozszerzono o nielokalność.
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Concrete beams under bending - calculations of size effects within stochastic elasto-plasticity with non-local softening
PublicationW artykule przedstawiono wyniki numerycznej analizy efektów skali (efektu deterministycznego i stochastycznego) w belkach betonowych nacięciem poddanych zginaniu z uwzględnieniem lokalizacji odkształceń. Obliczenia wykonano przy zastosowaniu metody elementów skończonych i sprężysto-plastycznego modelu z nielokalnym osłabieniem. Pokazano wpływ wielkości belek betonowych na nośność.
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Notched concrete beams under bending - calculations of size effects within stochastic elasto-plasticity with non-local softening
PublicationW artykule przedstawiono wyniki numerycznej analizy efektów skali (efektu deterministycznego i stochastycznego) w belkach betonowych nacięciem poddanych zginaniu z uwzględnieniem lokalizacji odkształceń. Obliczenia wykonano przy zastosowaniu metody elementów skończonych i sprężysto-plastycznego modelu z nielokalnym osłabieniem. Pokazano wpływ wielkości belek na nośność z uwzględnieniem stochastycznego rozkładu wytrzymałości na...
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The method of analysis of damage reinforced concrete beams using terrestial laser scanning
PublicationThe authors present an analysis of the possibility to assess deformations and mechanisms of destructing bent reinforced concrete beams using the terrestrial laser scanning. As part of the experiments carried out at the Regional Laboratory of Construction of the Concrete Structures Division of the Civil and Environmental Engineering Faculty at Gdansk University of Technology, the reinforced concrete beams were subjected to destruction...
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THE METHOD OF ANALYSIS OF DAMAGE REINFORCED CONCRETE BEAMS USING TERRESTRIAL LASER SCANNING
PublicationThe authors present an analysis of the possibility to assess deformations and mode of failure of R-C beams using terrestrial laser scanning. As part of experiments carried out at the Regional Laboratory of Construction (at Gdansk University of Technology), reinforced concrete beams were subjected to destruction by bending and by shear. The process of press impact on the reinforced concrete beam was recorded using terrestrial laser...
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FE-analysis of spacing of localized zones in reinforced concrete bars under tension using elasto-plasticity with non-local softening
PublicationW artykule przedstawiono wyniki numerycznej analizy lokalizacji odkształceń w pręcie żelbetowym poddanym rozciąganiu. Obliczenia wykonano przy zastosowaniu metody elementów skończonych i sprężysto-plastycznego modelu z nielokalnym osłabieniem. Pokazano wpływ różnych parametrów na nośność pręta i rozstaw lokalizacji.
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FE calculations of a deterministic and statistical size effect in concrete under bending within stochastic elasto-plasticity and non-local softening
PublicationW artykule przedstawiony wyniki obliczeń MES deterministycznego i statystycznego efektu skali w belkach betonowych podczas zginania. Zastosowano model w ramach stochastycznej sprężysto-plastyczności i nielokalnego osłabienia. Belki były geometrycznie podobne. Wyniki porównano z modelem efektu skali Bazanta.
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Experimental investigations of damage evolution in concrete during bending by continuous micro-CT scanning
PublicationThe paper describes experimental investigation results of fracture in notched concrete beams under quasi-static three-point bending. To visualize 3D fracture in concrete under bending, an extended X-ray micro-computed tomography system was used, i.e. the tomography system SkyScan 1173 was connected to the loading machine ISTRON 5569. This combined system enabled to shot images of deforming concrete beams during a continuous deformation...
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FE analysis of size effects in reinforced concrete beams without shear reinforcement based on stochastic elasto-plasticity with non-local softening.
PublicationW artykule przedstawiono wyniki analizy MES dotyczącej deterministycznego i statystycznego efektu skali w żelbetowych belkach bez zbrojenia na ścinanie. W analizie zastosowano prawo sprężysto-plastyczne z nielokalnym osłabieniem. Wyniki analizy porównano z doświadczeniami i modelem skali Bazanta.
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Experimental investigations on the mechanical properties and damage detection of carbon nanotubes modified crumb rubber concrete
PublicationThis study presents a modified crumb rubber (MCR) concrete design mix reinforced with multi-walled carbon nanotubes (MWCNTs), mechanical characterization, and cracking monitoring using the acoustic emission (AE) technique. The results showed that the bridging effect of MWCNTs and MCR in the concrete mix mitigated the shortcomings of MWCNT-MCR concrete and improved the flexural and compressive strengths by 18.3% and 26.5%, respectively,...
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Analysis of strain localization in reinforced concrete elements with explicit second-gradient strain damage approach
PublicationArtykuł omawia obliczanie elementów żelbetowych przy zastosowaniu modelu zniszczeniowego z degradacją sztywności z uwzględnieniem lokalizacji odkształceń. Obliczenia wykonano dla belek żelbetowych.
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Experimental validation of the use of energy transfer ratio (ETR) for damage diagnosis of steel-concrete composite beams
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FE-analysis of the beaviour of concrete elements with coupled elasto-plastic-damage models with non-local softening
PublicationArtykuł omawia wyniki symulacji zachowania sie elementów betonowych poddanych cyklicznemu obciążeniu. Do symulacji zastosowano połączone modele sprężysto-plastyczne z degradacją sztywności i z nielokalnym osłabieniem. Wyniki symulacji porównano z doswiadczeniami.
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Analysis of concrete behaviour under cycling within coupled elasto-plastic-damage with non-local softening
PublicationArtykuł omawia wyniki symulacji zachowania sie elementów betonowych poddanych cyklicznemu obciążeniu. Do symulacji zastosowano 3 połączone modele sprężysto-plastyczne z degradacją sztywności i z nielokalnym osłabieniem. Wyniki symulacji porównano z doświadczeniami laboratoryjnymi..
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Application of enhanced elasto-plastic damage models to concrete under quasi-static and dynamic cyclic loading
PublicationArtykuł omawia wyniki symulacji zachowania sie elementów betonowych poddanych zginaniu w czasie cyklicznego obciążenia. Do symulacji zastosowano 3 połączone modele sprężysto-plastyczne z degradacją sztywności i z nielokalnym osłabieniem. Wyniki symulacji porównano bezpośrednio z doświadczeniami.
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Enhanced coupled elasto-plastic-damage models to describe concrete behaviour in cyclic laboratory tests: comparison and improvement.
PublicationArtykuł omawia różne modele połączone sprężysto-plastyczne z degradacją sztywności do opisu zachowania się betonu pod obciążeniem cyklicznym. Modele zostały rozszerzone o długość charakterystyczną mikrostruktury w do opisu lokalizacji odkształceń. Wykonano obliczenia MES dla ściskania i zginania. Zaproponowano własny ulepszony model.
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Coupled elasto-plastic-damage model with non-local softening enhanced by viscosity to describe dynamic concrete behaviour
PublicationW artykule zaproponowano model do opisu betonu podczas dynamicznego obciążenia. Przyjęto model sprężysto-plastyczny z degradacją sztywności i nielokalnym osłabieniem rozszerzony o lepkość. Obliczenia MES dla elementów betonowych pod obciążeniem dynamicznym o różnej prędkości obciążenia porównano z doświadczeniami.
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Meso-mechanical modelling of damage in concrete using discrete element method with porous ITZs of defined width around aggregates.
PublicationArtykuł omawia wyniki obliczeń numerycznych pękania dla betonu stosując metodę elementów dyskretnych. Beton był opisany jako materiał 4-fazowy i był poddany zginaniu. W obliczeniach uwzględniono strefy ITZ o skończonej szerokości dookoła wszystkich ziaren kruszywa. Nacisk położono na przebieg mikropęknięć przy kruszywie. Wyniki porównano bezpośrednio z doświadczeniami. Obliczenia wykonano także dla szorstkich ziaren kruszywa....
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Numerical FDM modelling of wave propagation in concrete structure
PublicationThe article presents application of finite difference method to damage detection and its size evaluation in concrete structure by elastic wave propagation method. The simulations of wave propagation in concrete structure were performed for six different damage scenarios. Damages were modelled as areas with changed material properties. Investigation focused on the influence of damage size on the energy of wave reflection. Presented...
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Reference-free determination of debonding length in reinforced concrete beams using guided wave propagation
PublicationThis paper presents theoretical and experimental investigations of guided wave propagation in reinforced concrete beams, with pre-existing debonding between steel rebars and concrete blocks, for the purpose of damage detection. The primary aim of these investigations was a detailed analysis of the possible applications of wave propagation in single and multiple debonding detection in reinforced concrete structures and reference-free...
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Internal imaging of concrete fracture based on elastic waves and ultrasound computed tomography
PublicationThe condition assessment of concrete structures belongs to the greatest challenges of non-destructive testing. Monitoring the fracture process of concrete and detecting cracks at the earliest possible stage is a vital aspect to ensure the safety of civil engineering objects. The use of ultrasound tomography enables imaging the internal structure of a tested element. This study aims at the visualization of fracture damage in concrete...
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Guided Wave Propagation in Detection of Partial Circumferential Debonding in Concrete Structures
PublicationThe following article presents results of investigating the damage detection in reinforced concrete beams with artificially introduced debonding between the rod and cover, using a non-destructive method based on elastic waves propagation. The primary aim of the research was to analyze the possible use of guided waves in partial circumferential debonding detection. Guided waves were excited and registered in reinforced concrete...
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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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A continual model of a damaged medium used for analyzing fatigue life of polycrystalline structural alloys under thermal–mechanical loading
PublicationThe main physical laws of thermal–plastic deformation and fatigue damage accumulation processes in polycrystalline structural alloys under various regimes of cyclic thermal–mechanical loading are considered. Within the framework of mechanics of damaged media, a mathematical model is developed that describes thermal–plastic deformation and fatigue damage accumulation processes under low-cycle loading. The model consists of three...
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Debonding Detection in Reinforced Concrete Beams with the Use of Guided Wave Propagation
PublicationOne of the most frequent damage of the reinforced concrete structures is debonding between steel bar and concrete cover. In the case of debonding occurrence not only the strength of the structure decreases, but also it is more vulnerable to corrosion damages. For this reason fast and effective methods of debonding detection in an early stage of its development need a significant boost. The paper presents analytical and experimental...
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Failure Monitoring and Condition Assessment of Steel-Concrete Adhesive Connection Using Ultrasonic Waves
PublicationAdhesive bonding is increasingly being incorporated into civil engineering applications. Recently, the use of structural adhesives in steel-concrete composite systems is of particular interest. The aim of the study is an experimental investigation of the damage assessment of the connection between steel and concrete during mechanical degradation. Nine specimens consisted of a concrete cube and two adhesively bonded steel plates...
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Modelling reinforced concrete beams under mixed shear-tension failure with different continuous FE approaches
PublicationThe paper presents quasi-static numerical simulations of the behaviour of short reinforced concrete beams without shear reinforcement under mixed shear-tension failure using the FEM and four various constitutive continuum models for concrete. First, an isotropic elasto-plastic model with a Drucker-Prager criterion defined in compression and with a Rankine criterion defined in tension was used. Next, an anisotropic smeared crack...
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Characterization of Corrosion-Induced Fracture in Reinforced Concrete Beams Using Electrical Potential, Ultrasound and Low-Frequency Vibration
PublicationThe paper deals with the non-destructive experimental testing of the reinforced concrete beams under progressive corrosion. A series of experiments using electrical potential, ultrasound and low-frequency vibrations techniques are reported. Electrical potential and natural frequencies were used to characterise and monitor the corrosion process at its initial state. The P-wave velocity measurements were proved to be effective in...