- Naval Architecture and Marine Engineering, Buckling and Ultimate Strength of Ships and Offshore Structures, Marine Corrosion and Protection, Steel Box Girder, Marine Structures, Strength of materials, and 8 moreSteel Structure, Offshore Structures, Mechanical Properties of Materials, Finite Element Modeling, Ultimate strength of structures and materials, Stress-Strain, Corrosion Engineering, and Finite Element Analysis (FEA)edit
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The objective of this paper is to describe the experimental assessment of the ultimate strength of a severely corroded box girder subjected to a uniform bending moment resulting from four-point loading. Three box girders that could... more
The objective of this paper is to describe the experimental assessment of the ultimate strength of a severely corroded box girder subjected to a uniform bending moment resulting from four-point loading. Three box girders that could simulate the behaviour of midship sections have been deteriorated in corrosive seawater environment to simulate different levels of corrosion degradation of ageing ship structures.
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This paper presents a corrosion-dependent analysis of the ultimate strength analysis of aged box girders based on experimental results. Three multispan corroded stiffened box girders subjected to four-point vertical load are analyzed,... more
This paper presents a corrosion-dependent analysis of the ultimate strength analysis of aged box girders based on experimental results. Three multispan corroded stiffened box girders subjected to four-point vertical load are analyzed, idealizing the behavior of midship sections of full ships. The specimens have three levels of corrosion. Two corrosion-dependent formulas for assessing the ultimate strength as well as the ultimate bending moment of corroded structures are proposed. Using a time-dependent corrosion growth model, equivalent time-dependent formulations are developed. The effect of corrosion degradation on the residual stresses during the service life is also analyzed, and a regression equation for predicting the remaining residual stresses along the service life is proposed. Finally, a corrosion-dependent moment-curvature relationship has been developed accounting for the changes in geometrical characteristics and material properties of the tested box girders.
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Corrosion degrades mechanical properties and fatigue life of structures considerably; hence reliable numerical fatigue analysis is essential for assessing the remaining life of aged steel structures. In this paper, the influence of... more
Corrosion degrades mechanical properties and fatigue life of structures considerably; hence reliable numerical fatigue analysis is essential for assessing the remaining life of aged steel structures. In this paper, the influence of corrosion topology and the minimum thickness location on the stress concentration over corroded specimens and, in consequence, their fatigue life was comprehensively studied. The corroded surfaces were modelled using random spatial distributions approach. The results of the numerical simulation have been compared with published fatigue test results. The comparison showed good agreement between the experimental results and the adopted approaches for fatigue life assessment.
Corrosion has a significant deteriorative effect on fatigue life of aged ship and offshore structures; hence reliable numerical fatigue life analysis of aged ship structures is crucial for safe operation. The reliability of the fatigue... more
Corrosion has a significant deteriorative effect on fatigue life of aged ship and offshore structures; hence reliable numerical fatigue life analysis of aged ship structures is crucial for safe operation. The reliability of the fatigue damage assessment techniques depends on the quality of the S-N curve which should account for corrosion degradation. In this paper, the different factors affecting the randomness of stress concentration and fatigue life of corroded specimens have been studied. It was demonstrated that the Stress Concentration, which results from the distinctive thickness variation of the corroded specimens, significantly depends on the mean and minimum thickness of the corroded plate. The equivalent thickness of a typical plate, which has the same fatigue strength of the corresponding corroded one under the same cyclic load, was investigated. A time-dependent S-N curve of corroded structures considering the deterioration of material mechanical properties was proposed....
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Tubular members are widely used in oil and gas offshore production and drilling structures either fixed or mobile units. Due to complex operational conditions, the tubular members are subjected to both age and mechanical related damage,... more
Tubular members are widely used in oil and gas offshore production and drilling structures either fixed or mobile units. Due to complex operational conditions, the tubular members are subjected to both age and mechanical related damage, which in turn affect the ability of the structure to withstand the applied loads. This motivates the importance of investigating the behavior of tubular members considering the presence of dentation resulting from collision or falling objects and consequently assessing the residual strength of the damaged members accurately. A series of finite element analysis are performed to study the pre- and post-ultimate strength behavior of intact and locally dented un-stiffened steel tubular members subjected to four-point bending. The effects of dent geometrical parameters; length, width, depth, orientation, and location on the ultimate load carrying capacity are analyzed. The ratio between the diameters to the shell thickness is varied, where combined local ...
Cracks of various sizes and orientations may arise at many locations under conditions of pitting corrosion, local stress concentration, fatigue and impact loads. It is essential to evaluate the effect of cracks on the ultimate strength... more
Cracks of various sizes and orientations may arise at many locations under conditions of pitting corrosion, local stress concentration, fatigue and impact loads. It is essential to evaluate the effect of cracks on the ultimate strength and collapse behaviors of various ship structural members, so as to avoid complete structural failure. The assessment of this effect would serve the life-cycle management, maintenance and repair strategies aiming to ensure structural longevity of ships and offshore steel structures. A review of the advances carried out during the last few years, shows that the effect of locked and propagated cracks on the ultimate strength behavior is complex since it cannot be isolated from the effect of initial imperfections and corrosion. Published experimental attempts were a good base, but most literature is based on finite element modeling that proved to be a useful tool to generate different possible damage scenarios. Recent empirical formulae had been proposed...
Abstract A series of compressive tests of high tensile steel stiffened plates with multiple openings have been conducted. Different degrees of openings represented by different sets of openings are considered, and their effect on the... more
Abstract A series of compressive tests of high tensile steel stiffened plates with multiple openings have been conducted. Different degrees of openings represented by different sets of openings are considered, and their effect on the ultimate carrying capacity is explored. The results are discussed, and several conclusions are stated. Based on the experimental results, several relationships predicting the ultimate axial capacity of high tensile steel stiffened plates with multiple openings as a function of remaining volume and degree of openings are developed. Also, a failure assessment diagram of stiffened plates with openings is defined. Finally, a comparison with other published experimental results for deteriorated mild steel plates with multiple opening is performed.
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Abstract This work experimentally investigates the influence of different opening sizes and shapes, different steel materials and structural configurations on the ultimate strength of steel plates. A series of experiments have been... more
Abstract This work experimentally investigates the influence of different opening sizes and shapes, different steel materials and structural configurations on the ultimate strength of steel plates. A series of experiments have been carried out for unstiffened plates and stiffened panels having an opening of different shape and size in addition to different constructional steels; high tensile and mild steel. The effect on the ultimate load carrying capacity of the opening sizes and shapes, different steels and structural configurations, post-collapse deformations and strain energy density are investigated and analysed. Several relationships of the ultimate stress ratio, ultimate load carrying capacity ratio for different steels as a function of the residual breadth ratio are presented and discussed. A relationship showing the effect of different structural configurations on the ultimate load carrying capacity ratio is presented. Several observations and concluding remarks are derived from the experimental results.
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ABSTRACT The objective of this work is to analyse the influence of corrosion cleaning employing sandblasting, sand-paper cleaning, high-pressure-fresh-water-cleaning and corrosion cleaning by hammering on the mechanical properties of aged... more
ABSTRACT The objective of this work is to analyse the influence of corrosion cleaning employing sandblasting, sand-paper cleaning, high-pressure-fresh-water-cleaning and corrosion cleaning by hammering on the mechanical properties of aged steel specimens. Tensile tests of cleaned corroded specimens are carried out. The specimens were cut from steel box girders, corroded in open sea water. The material properties of five groups of corroded specimens are experimentally estimated including the modulus of elasticity, yield stress, tensile strength and total uniform elongation. The trend of mechanical properties is analysed as a function of the degree of degradation and cleaning procedure, identifying that the cleaning treatment of the corroded surface significantly influences the mechanical properties and stress–strain relationships. A multi-criteria decision technique is employed to identify the most suitable cleaning technique accounting for the efficiency of the cleaning process and reducing the scatter in the mechanical properties of the cleaned corroded specimens.
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Abstract To ensure the structural capacity of plates with multiple openings subjected compressive loads and to find a better design solution, the strength of different structural configurations is analysed here. A series of experimental... more
Abstract To ensure the structural capacity of plates with multiple openings subjected compressive loads and to find a better design solution, the strength of different structural configurations is analysed here. A series of experimental buckling collapse tests have been carried out for steel plates with multiple openings, of three different degrees of openings. Each degree of opening is represented by two groups of openings, to investigate the effect of possible design solutions aiming for the maximum compressive strength. The effect of corrosion wastage is also studied, where the specimens are naturally corroded. The effect of manufacturing defects as the initial imperfection on both compressive capacity and the final deformed shapes is also studied. Several relationships as functions of the degree of openings and remaining volume of the corroded plates with multiple openings are developed, and recommendations regarding the early design stage are provided.
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Abstract This work studies the combined effect of both geometrical characteristics (opening and initial imperfections) and age related damage (corrosion and cracks) on the local and global responses of thin rectangular steel plates. A... more
Abstract This work studies the combined effect of both geometrical characteristics (opening and initial imperfections) and age related damage (corrosion and cracks) on the local and global responses of thin rectangular steel plates. A series of experimental tests has been conducted for in-service steel plates with a circular opening and subjected to several damage actions and uni-axial compression. Different initial imperfection shapes and amplitudes, corrosion degradation levels and locked crack lengths are considered. Several collapse modes were observed and the reasons for their occurrence are discussed. The experimental results of force-displacement and stress––strain relationships are presented and the relevant dissipated energies, resilience and toughness are estimated. The experimental results are compared with published experimental results, confirming the complexity of the plate behaviour accounting for different damage scenarios.
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This work investigates the residual structural capacity of experimentally tested steel plates with a large central ellipsoidal opening with and without locked cracks, subjected to uni-axial compressive load. A series of experimental tests... more
This work investigates the residual structural capacity of experimentally tested steel plates with a large central ellipsoidal opening with and without locked cracks, subjected to uni-axial compressive load. A series of experimental tests have been carried out. The tested plates were a part of a real box structure, which represents a scaled midship section of single hull tanker ship, exposed to a corrosive seawater environment. A plate with one large opening with different crack lengths is analysed. The influence of the combined effect of the plate opening and different crack lengths on the residual strength is investigated. The experimental results; force–displacements relationships, dissipated energy, stress–strain relationships, resilience and toughness are presented and analysed. The stresses at particular locations along the plate specimens are estimated and analysed. Several collapse modes are observed and discussed. The experimental results of the tested specimens have been compared with other test results for plates with different opening sizes, confirming the significance of the combined effect of an opening with simultaneous locked cracks on the local and global structural behaviour.
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Abstract The effect of sandblasting and sand paper cleaning on the mechanical properties of corroded steel specimens is studied. An experimental assessment of tensile strength of small scale steel corroded specimens is performed. The... more
Abstract The effect of sandblasting and sand paper cleaning on the mechanical properties of corroded steel specimens is studied. An experimental assessment of tensile strength of small scale steel corroded specimens is performed. The specimens were cut from a box girder, initially corroded in sea water conditions and later the specimens were subjected to sandblast and sandpaper cleaning. Tension tests are performed to determine the mechanical properties of three groups of specimens, including non-maintained, sandblasted, and sandpaper cleaned, corroded specimen, allowing the estimation of the modulus of elasticity, yield stress, tensile strength, total uniform elongation and n and K strength parameters. Regression equations of the material properties are derived as a function of the degree of corrosion and maintenance actions. It is shown that these two methods of removing corrosion products from the surface of plate specimens have different effects on their mechanical properties and stress-strain relationships. Based on the achieved results a simplified stress-strain curve accounting for the corrosion degradation and maintenance actions is developed, which may be used for structural assessment of ageing marine structures.
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Abstract This work assesses the ultimate strength of experimentally tested steel plates with a large central elongated circular opening, subjected to uni-axial compressive load. A series of experimental tests have been carried out on... more
Abstract This work assesses the ultimate strength of experimentally tested steel plates with a large central elongated circular opening, subjected to uni-axial compressive load. A series of experimental tests have been carried out on plates that were part of a real structure, which represents a scaled midship section of single hull tanker ship, tested in a corrosive environment in direct contact with seawater. One elongated circular opening shape with different sizes is analyzed and the effect of the opening size on the ultimate strength is investigated. The force–displacements relationships are presented and the dissipated energy is analyzed. Stress–strain relationships, resilience and toughness have been evaluated. The collapse modes are discussed and the ultimate strength has been compared with recently published studies showing a good agreement in the trend.
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The present paper assesses the ultimate bending moment of steel box girders subjected to intensive non-uniform corrosion degradation. A comparison between the experimental results of three corroded box girders and different existing... more
The present paper assesses the ultimate bending moment of steel box girders subjected to intensive non-uniform corrosion degradation. A comparison between the experimental results of three corroded box girders and different existing formulations has been performed. The moment–curvature relationship for the three corroded box girders has been calculated using the Common Structural Rules iterative process and the finite element method, leading to a development of corrosion scale factors to account for both geometrical and mechanical properties changes. Based on the experimental results, a relationship has been developed to calculate the equivalent Young's modulus of corroded structures as a function of the total reduction in cross-sectional area. A systematic procedure for the application of the newly developed fast approach and the new equivalent Young's modulus has been presented that can be used for any ultimate bending moment–curvature calculation tools.
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The present paper assesses the ultimate bending moment of steel box girders subjected to intensive non-uniform corrosion degradation. A comparison between the experimental results of three corroded box girders and different existing... more
The present paper assesses the ultimate bending moment of steel box girders subjected to intensive non-uniform corrosion degradation. A comparison between the experimental results of three corroded box girders and different existing formulations has been performed. The moment–curvature relationship for the three corroded box girders has been calculated using the Common Structural Rules iterative process and the finite element method, leading to a development of corrosion scale factors to account for both geometrical and mechanical properties changes. Based on the experimental results, a relationship has been developed to calculate the equivalent Young's modulus of corroded structures as a function of the total reduction in cross-sectional area. A systematic procedure for the application of the newly developed fast approach and the new equivalent Young's modulus has been presented that can be used for any ultimate bending moment–curvature calculation tools.
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The objective of this work is to perform a hull girder ultimate strength verification according to the Class Society rules based on experimental results and the dimensional theory. The results of the ultimate strength test of three box... more
The objective of this work is to perform a hull girder ultimate strength verification according to the Class Society rules based on experimental results and the dimensional theory. The results of the ultimate strength test of three box girders, that may represent the behaviour of a mid-ship section of a ship, deteriorated in a real corrosive seawater environment representing different levels of corrosion degradation of ageing ship structures, is used to evaluate the ultimate strength. The analysis is based on a structural model, used in the experimental test, which maintains the first-order similarity between the model and real structures. The present analysis may be used to validate the global ultimate strength of ship hull structures in the phase of the new structural design or during the service life and to calibrate the new developed codes.
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All offshore steel structures associated with the drilling and production of offshore gas and oil are provided with Cathodic Protection (CP).Without effective CP, these structures will suffer general corrosion loss resulting in... more
All offshore steel structures associated with the drilling and production of offshore gas and oil are provided with Cathodic Protection (CP).Without effective CP, these structures will suffer general corrosion loss resulting in structural weakness and possibly perforation of members. The purpose of this paper is to focus on the procedure of the galvanic (sacrificial) anode, as well as the impressed current cathodic protection system applied in the field; guided by specifications, standards and recommended practices for corrosion control. Also the structural analysis of a KT-joint model is carried out to find the effect of uniform corrosion (material loss) on the structure strength over the structure service life.
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The objective of this study is to analyze the hot spot and notch stresses of two welded specimens subjected to fatigue load. The first specimen is a base plate strengthened by doubler plates and the second one is double lap joint. Three... more
The objective of this study is to analyze the hot spot and notch stresses of two welded specimens subjected to fatigue load. The first specimen is a base plate strengthened by doubler plates and the second one is double lap joint. Three approaches for determining the stress distributions for fatigue analysis of welded structures are applied, the structural hot spot stress approach, the Xiao-Yamada approach and the effective notch stress approach. The influence of geometrical parameters of welded joints is studied. The gap between the double plate and the base plate is modelled as 0.1 [mm] void space with contact elements. Based on the results of the finite element models analyzed, polynomial regression equations assessing the stress concentration factors at the weld toe and weld root are derived.
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An experimental test was conducted of a multispan stiffened box girder model representing a midship section, to obtain information on the behaviour, modes of failure and load-carrying capacity. The box girder was subjected to four-point... more
An experimental test was conducted of a multispan stiffened box girder model representing a midship section, to obtain information on the behaviour, modes of failure and load-carrying capacity. The box girder was subjected to four-point bending moment. The experimental results are presented and compared with an ultimate bending moment empirical formula. Three loading cycles have been used to release the residual
stresses and one to achieve the ultimate strength. The evaluation of the test results has shown that, for the pure bending loading, the specimen demonstrated definite stress redistribution capabilities and considerable ultimate strength. Failure modes were characterized by tension field yielding, tripping of longitudinal stiffeners and out-of-plane deformations of the plates.
stresses and one to achieve the ultimate strength. The evaluation of the test results has shown that, for the pure bending loading, the specimen demonstrated definite stress redistribution capabilities and considerable ultimate strength. Failure modes were characterized by tension field yielding, tripping of longitudinal stiffeners and out-of-plane deformations of the plates.
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The aim of this work is to analyse the local and the global structural behaviour of rectangular steel plates with a local dent. Nonlinear finite element analyses have been performed to explore the effect of different dent depths on the... more
The aim of this work is to analyse the local and the global structural behaviour of rectangular steel plates with a local dent. Nonlinear finite element analyses have been performed to explore the effect of different dent depths on the ultimate strength and the post-collapse behaviour. The post-collapse modes are discussed and the change of the buckling mode for different plate thickness ranges is categorized. The behaviour in post-collapse regime is analysed using the defined stress–strain rate. Two relationships have been developed to estimate the ultimate strength reduction as a function of the plate slenderness and dent ratio. Based on the existing ultimate strength design formula and a new developed factor, a new formulation for ultimate strength of damaged plate has been introduced accounting for the effect of local dent. The new developed formulation is capable to account for an initial global imperfection, residual stresses, openings, corrosion deterioration and existence of dents.
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The objective of this paper is to analyze the ultimate strength of a slightly corroded box girder subjected to four-point loading resulting in a constant vertical bending moment along the box girder, using non-linear finite element... more
The objective of this paper is to analyze the ultimate strength of a slightly corroded box girder subjected to four-point loading resulting in a constant vertical bending moment along the box girder, using non-linear finite element method. A series of nonlinear collapse analyses have been performed and the ultimate strength has been analyzed using different material models and also different weld toe shapes. Different elasto-plastic material models have been developed accounting for the residual stresses effect and post-buckling behavior. Comparisons between numerical and experimental results have been performed for the slightly corroded box showing a very good agreement
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This paper presents a finite element model and an analysis of large-scale specimen of box girder subjected to four-point loading. Extensive nonlinear finite element analyses have been performed to find out the best configuration of the... more
This paper presents a finite element model and an analysis of large-scale specimen of box girder subjected to four-point loading. Extensive nonlinear finite element analyses have been performed to find out the best configuration of the model by varying the initial imperfection (shape and amplitude) and mesh size that affect the ultimate strength and post-collapse behaviour. The results achieved by the use of the adopted finite element models demonstrate a very good agreement with the three-linear trend of the bending moment-curvature behaviour of an intact box girder. Furthermore, a comparison with different box girders having different material properties and geometrical descriptions has been carried out.
FE parameters estimation and analysis of ultimate strength of box girder. Available from: https://www.researchgate.net/publication/260834136_FE_parameters_estimation_and_analysis_of_ultimate_strength_of_box_girder [accessed May 16, 2015].
FE parameters estimation and analysis of ultimate strength of box girder. Available from: https://www.researchgate.net/publication/260834136_FE_parameters_estimation_and_analysis_of_ultimate_strength_of_box_girder [accessed May 16, 2015].
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The present study is focused on assessing the effects of localized pitting corrosion on the collapse strength of unstiffened plates. A series of non-linear (FE) analysis using ANSYS program are performed to explore the effect of pitting... more
The present study is focused on assessing the effects of localized pitting corrosion on the collapse strength of unstiffened plates. A series of non-linear (FE) analysis using ANSYS program are performed to explore the effect of pitting corrosion on the collapse strength of both rectangular and square steel plate subjected to axial compression, by varying the pitting distribution intensity as well as the plate geometry. A formula for predicting the collapse strength reduction due to pitting corrosion is derived by using regression analysis.
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This paper analyses the failure modes obtained in experiments of multispan corroded box-girders, representing midship hull sections subjected to a uniform bending moment. A comparison of the behaviour of three tested corroded box-girder... more
This paper analyses the failure modes obtained in experiments of multispan corroded box-girders, representing midship hull sections subjected to a uniform bending moment. A comparison of the behaviour of three tested corroded box-girder specimens is performed with respect to collapse modes, strain measurements, residual stresses, load-displacement relationship, moment-curvature relationship and the effect of different corrosion levels on structural integrity.
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The objective of this work is to compare the stress-strain behaviour of rectangular steel plates accounting for the presence of an opening or a dent, when a uniaxial compressive load is applied. Extensive nonlinear finite element analyses... more
The objective of this work is to compare the stress-strain behaviour of rectangular steel plates accounting for the presence of an opening or a dent, when a uniaxial compressive load is applied. Extensive nonlinear finite element analyses are performed, where the effect of several governing parameters on the stress-strain relationship are analysed, including plate thickness, opening and dent sizes, shape and depth. The similarity in the structural response of a plate with a dent or an opening is identified. The pre and post buckling behaviour, stress-strain relationship and the ultimate strength lateral deformation are discussed and several conclusions are derived.
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The objective of this study is to analyse a severely damaged box-girder subjected to combined action of non-uniform and inter-crystalline corrosion. The inter-crystalline corrosion, due to the differences in the metal composition of the... more
The objective of this study is to analyse a severely damaged box-girder subjected to combined action of non-uniform and inter-crystalline corrosion. The inter-crystalline corrosion, due to the differences in the metal composition of the base and weld toe material, degrades the weld toe between the stiffeners and associated plates leading to a disintegration of structural components and a severe reduction of the strength. In addition, damages originating from dropping objects or collision may also contribute to the strength reduction. The present work investigates the effect of different damage scenarios leading
to a symmetrical and asymmetrical stiffness reduction in the strength capacity of a severely corroded and damaged three-bay box girder. A series of static nonlinear finite element analyses are conducted. Different severities of the assumed damage scenarios are considered to identify both symmetric and asymmetric stiffness and strength reductions. The partial and entire damage of one ring-web-frame, transforming the box-girder from a three to two-bay structure is also studied. The effect of stiffness reduction on the moment-curvature relationships, failure modes, ultimate strength as well as the movement of the neutral axis are presented and discussed.
to a symmetrical and asymmetrical stiffness reduction in the strength capacity of a severely corroded and damaged three-bay box girder. A series of static nonlinear finite element analyses are conducted. Different severities of the assumed damage scenarios are considered to identify both symmetric and asymmetric stiffness and strength reductions. The partial and entire damage of one ring-web-frame, transforming the box-girder from a three to two-bay structure is also studied. The effect of stiffness reduction on the moment-curvature relationships, failure modes, ultimate strength as well as the movement of the neutral axis are presented and discussed.
The objective of this work is to analyze the initial and post-collapse plate deflections based on measurement records of the experiments of three corroded box girders subjected to pure vertical bending loading inducing a compressive... more
The objective of this work is to analyze the initial and post-collapse plate deflections based on measurement records of the experiments of three corroded box girders subjected to pure vertical bending loading inducing a compressive stress on deck. The effect of initial imperfections and corrosion degradation on the final post-collapse deformation shape has been investigated and a relationship between different loading responses, shape of initial imperfections and plate slenderness has been derived. Analyzing initial imperfections, plate slenderness and final post-collapse deformations, a slenderness criterion has been established to predict the post-collapse deformation shape.
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This paper presents an experimental study on the effect of corrosion degradation on the ultimate strength of corroded steel box girders. Two specimens, built as box girders, were immersed in natural sea water in a harbour. After... more
This paper presents an experimental study on the effect of corrosion degradation on the ultimate strength of corroded steel box girders. Two specimens, built as box girders, were immersed in natural sea water in a harbour. After corrosion, the box girder sections were tested under four-point loading, producing a constant bending moment until collapse. The effect of corrosion degradation on the ultimate strength of the box girder is analysed, and dissipated energy, compliance, ductility and elastic limit are verified and discussed. A significant reduction in the stiffness, stress–strain relationship and elastic modulus was observed.
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An ultimate strength analysis is performed of steel plates with a large opening subjected to axial compressive load. A series of nonlinear finite element analysis have been conducted. First, the ultimate strength of plates without an... more
An ultimate strength analysis is performed of steel plates with a large opening subjected to axial compressive load. A series of nonlinear finite element analysis have been conducted. First, the ultimate strength of plates without an opening are numerically studied by varying the finite element size, boundary conditions, and thickness and is compared with existing empirical expressions. The effect of the opening ratio and orientation to the ultimate strength of plates is investigated. An expression is developed to estimate the ultimate strength of plates with an opening subjected to compressive loading as a function of the plate slenderness and residual plate-breadth ratio. The failure modes are discussed and the change of the failure mode at a certain residual breadth ratio is also investigated.
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This work deals with the evaluation of the ultimate bending moment of a severely corroded box girder subjected to uniform vertical bending moment through a series of nonlinear finite element analysis. Two models of corrosion degradation... more
This work deals with the evaluation of the ultimate bending moment of a severely corroded box girder subjected to uniform vertical bending moment through a series of nonlinear finite element analysis. Two models of corrosion degradation have been adopted, one is an average general corrosion thickness reduction, and the other is the real thickness of the corroded plates. New stress–strain relations have been developed to account for the effect of corrosion on the flexural rigidity. To validate the new developed stress–strain relationships, a comparison between the finite element analysis results using the existing stress–strain models, the newly developed ones and the experimental test results of a severely corroded box girder have been conducted. The comparison showed a good agreement and supported the choice of the newly developed stress–strain relationships of corroded structures.
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This paper analyses the failure modes based on experimental test results of multispan corroded box-girders, representing amidships ship hull section and subjected to four-point loading. Comparative study for three tested corroded box... more
This paper analyses the failure modes based on experimental test results of multispan corroded
box-girders, representing amidships ship hull section and subjected to four-point loading. Comparative study
for three tested corroded box girder specimens with respect to collapse modes, strain measurements, residual
stresses, load-displacement and moment-curvature relationships and the effect of different corrosion levels on
structural integrity are performed.
box-girders, representing amidships ship hull section and subjected to four-point loading. Comparative study
for three tested corroded box girder specimens with respect to collapse modes, strain measurements, residual
stresses, load-displacement and moment-curvature relationships and the effect of different corrosion levels on
structural integrity are performed.
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The objective of this paper is to analyse the ultimate strength of ageing ship structures based on experimental and numerical assessments. Three experimental ultimate strength tests have been carried out on box girders under vertical... more
The objective of this paper is to analyse the ultimate strength of ageing ship structures based on experimental and numerical assessments. Three experimental ultimate strength tests have been carried out on box girders under vertical bending moment and several effects have been detected due to corrosion. Extensive nonlinear finite element analyses have been performed to compare the numerical and experimental results. The ultimate bending moment of corroded box girders has been compared with existing formulas. A relationship to calculate the equivalent tangent modulus as a function of the total reduction of the cross-sectional area due to corrosion degradation has been proposed. A new stress–strain relationship has been developed, taking into account the residual stresses and the corrosion effect, which may be directly used as a master stress–strain curve for a non-linear finite element analysis.
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This work deals with the evaluation of the structural capacity of corroded box girders accounting for a presence of a dent and subjected to uniform vertical bending moment. A series of static nonlinear finite element analyses are... more
This work deals with the evaluation of the structural capacity of corroded box girders accounting for a presence of a dent and subjected to uniform vertical bending moment. A series of static nonlinear finite element analyses are conducted. The structural damage is modelled as an indentation,
where several locations on deck panel are considered with different dent depths. The effect of the presence
of the indentation (location and depth) as a result of a dropping object on the ultimate bending moment
and flexural rigidity is investigated. The effect of the boundary conditions as free and constrained torque
is explored. The collapse modes are analysed and the effect of the dent damage on changing the final collapse mode is identified. Several observations and conclusions are derived, which benefit repair and maintenance planning and may be used as an input for the global strength assessment of aging and damaged structures.
where several locations on deck panel are considered with different dent depths. The effect of the presence
of the indentation (location and depth) as a result of a dropping object on the ultimate bending moment
and flexural rigidity is investigated. The effect of the boundary conditions as free and constrained torque
is explored. The collapse modes are analysed and the effect of the dent damage on changing the final collapse mode is identified. Several observations and conclusions are derived, which benefit repair and maintenance planning and may be used as an input for the global strength assessment of aging and damaged structures.
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ABSTRACT This work deals with the evaluation of the ultimate bending moment of two box girders subjected to different levels of corrosion degradation and experimentally tested under pure vertical bending moment. A series of nonlinear... more
ABSTRACT This work deals with the evaluation of the ultimate bending moment of two box girders subjected to different levels of corrosion degradation and experimentally tested under pure vertical bending moment. A series of nonlinear finite element analysis have been conducted. Two models of corrosion degradation have been used representing an average general corrosion thickness reduction, and the real corrosion thickness as it is measured. Based on the real corrosion measurements, experimental ultimate strength and finite element calculations, a relationship has been developed to predict the expected difference in the ultimate strength calculations based on the FE models representing the corrosion degradation as an average thickness reduction or as the real measured corrosion reduction.