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This paper addresses the challenge of enhancing the bending capacity of beams through a cost‐effective and practical approach. Current methods are often expensive, brittle, time‐intensive, or massive. In response, an alternative method is proposed that involves the utilization of post‐tensioned heavy‐duty metal straps wrapped around steel plates anchored to the beams. To evaluate the effectiveness of the method, six large‐scale normal reinforced concrete beams were constructed with a width of 160 mm and a depth of 240 mm, and a clear span of 1900 mm. The testing parameters were the position of the steel plates along the length of the beam and the position of the metal straps along the height of the steel plates. Quantitative results demonstrate a significant enhancement in the load‐carrying capacity of the beams. Compared to the control specimen, the method led to a minimum increase of 40% of load carrying capacity and a maximum increase of 66%. Key influencing factors include the location of the metal straps on the steel plates (120 or 90 mm away from the bottom of the beam) and the position of the steel plates on the face of the beam (650 mm or 350 away from the edge of the beam). Notably, the load‐carrying capacity increases when the metal straps are positioned lower on the steel plates and the plates are placed further away from the center of the beam. Finally, analytical results obtained using VecTor2 software align well with experimental findings. [ABSTRACT FROM AUTHOR]

Local buckling of steel plates is a major concern, as it dominates the plastic mechanism and reduces the ultimate strength of the steel plates depending upon their slenderness. At elevated temperatures, material nonlinearities result in a further reduction in the stability, stiffness, and strength of thin steel plates. Numerical simulations have been performed on stiffened and unstiffened steel plates at elevated temperatures under uniaxial compression load for different slenderness using commercially available FE software ABAQUS. The established finite element model, which depicts the local buckling behaviour and ultimate post-buckling strength of square and rectangular steel plates, has been the basis for a number of parametric investigations, all of which have been conducted using shell finite elements. The designed specification offered by North American Standards (ANSI/AISC 360-16) and European Standards (EN 1993-1-2), which employ a stress-based method to determine the ultimate post-buckling strength of steel plates for local buckling at elevated temperature, has also been compared with the obtained results. According to this investigation, EN 1993-1-2 produces results that are excessively conservative at higher temperatures. To overcome this, an attempt has been made by replacing the normal temperature parameter by a temperature-dependent non-dimensional slenderness ratio for predicting the ultimate strength of steel plates in fire exposure conditions. Further, this study provides some critical highlights on the behavior of steel plates of two different aspect ratios at elevated temperatures under compressive loads. The design formulations have also been proposed for estimating the ultimate strength of thin square and rectangular steel plates under compression. A good correlation has been observed in predicting the strength of the new design approach compared with existing experimental and computational results. The reliability and accuracy assessments of the proposed approach have been illustrated in brief. [ABSTRACT FROM AUTHOR]

The uncertainty that characterizes the external mechanical loads to which any connection plate in steel structures is subjected determines the non-uniqueness of the isochoric deformation distributions. Since the eddy currents induced on the plates produce magnetic field maps with a high fuzziness content, similar to those of the isochoric deformations, their use can be exploited to evaluate the extent of the external load that determines a specific induced current map. Starting from an approach known in the literature, according to which the map-external load association is operated through fuzzy similarity computations, in this paper, we generalize this method by reformulating it in terms of intuitionistic fuzzy logic by proposing a classification based on divergence computations. Our approach, acting adaptively on the fuzzification of the maps, results in a better classification percentage, besides significantly reducing the presence of doubtful cases due to the uncertainty of each applied load. Furthermore, a FEM software tool was developed, which turned out to be, to a certain extent, a substitute for the experimental procedure, notoriously more expensive. Even if the procedure was applied on plates subjected to bi-axial loads, it could be used for other types of loads since the classification operator processes the eddy current maps exclusively, regardless of their cause. [ABSTRACT FROM AUTHOR]

In the protective engineering field, close-range explosions produce more energy and are more likely to cause severe damage to building structures than long-range explosions. In current standards, close-range explosions are defined as an explosion with a scale distance of less than 1.2 m/kg1/3. Besides, the steel plate's dynamic response is critical, especially under the blast loads generated by different shapes of explosives. For cylindrical explosives most commonly used in military and engineering, this study carried out experimental and numerical simulation studies on steel plates under the close-range air blast loads generated by different H/D cylindrical explosives (0.5≤H/D≤3.0). First, close-range air blast load tests were performed to study the failure modes of steel plates at different scale distances. The height-to-bottom diameter H/D ratio was defined as the shape factor of cylindrical explosive, and the effect of H/D on the failure deformation and dynamic response of the steel plate was quantitatively studied. Finally, the characteristics of shock waves generated by cylindrical explosives with different H/D were analyzed to determine the influence of H/D on the spatial distribution of shock waves. The results showed that with the increase of H/D , the steel plate deformation and damage gradually decreased. When the scale distance was more significant than or equal to 0.38, there was no crack in the steel plate, and the residual deflection gradually reduced with the increase of H/D. Despite the different scale distances, the residual deflections showed similar trends with increasing H/D. When the scale distance was less than or equal to 0.30, the steel plate cracked, and the crack area gradually decreased with increased H/D. [ABSTRACT FROM AUTHOR]

Welded lap joints play a vital role in a wide range of engineering structures such as pipelines, storage tanks, pressure vessels, and ship hulls. This study aims to investigate the propagation of ultrasonic guided waves in steel welded lap joints for the baseline-free inspection of joint defects using the mode conversion of Lamb waves. The finite element method was used to simulate a single lap joint with common defects such as corrosion and disbonding. To identify the propagating wave modes, a wavenumber–frequency analysis was conducted using the 2D fast Fourier transform. The power loss of the transmitted modes was also determined to identify damage in the lap joints. The results indicate that the A0 incident in pristine conditions experienced significant transmission losses of about 9.5 dB compared to an attenuation of 2.8 dB for the S0 incident. The presence of corrosion was found to reduce these transmission losses by more than 28%. In contrast, introducing disbonding in the lap joint increased the transmission loss of the S0 incident, while a negligible loss was observed for the A0 incident. The mode-converted S0 (MC-S) and mode-converted A0 (MC-A0) incidents were found to exhibit a unique sensitivity to the presence of corrosion and disbonding. The results indicate that MC-S0 and MC-A0 as well as Lamb mode incidents interact differently in terms of corrosion and disbonding, providing a means to identify damage without relying on baseline signals. [ABSTRACT FROM AUTHOR]

This study aims to design efficient and reliable artificial intelligence vision detection models to improve detection efficiency and accuracy. The study filters defect-free images by image preprocessing and region of interest detection techniques. AlexNet network is enhanced by introducing attention mechanism modules, deep separable convolutions, and more to effectively boost the network's feature extraction capacity. An area convolutional neural network is developed to rapidly identify and locate defects on steel plate surfaces, utilizing an enhanced AlexNet network for feature extraction. Results demonstrated that the algorithm attained an average detection rate of 98 % and can identify defects in a minimal time of only 0.0011 seconds. For the detection of six types of steel plate defects, the average accuracy of the optimized fast regional convolutional neural network reached more than 0.9, especially for the detection of small-size defects with excellent performance. This improved AlexNet network has a great advantage in F1 value. The conclusion of the study shows that the designed artificial intelligence vision detection model has high detection accuracy, speed, and performance stability in steel plate surface defect detection and has a wide range of application prospects. [ABSTRACT FROM AUTHOR]

In the Middle East, wall-like reinforced concrete (RC) columns are a common choice in multistory buildings. Sometimes, these columns need axial retrofitting for increased load capacity. In practice, unstrengthened columns bear their load, and if retrofitting is necessary, the load is released before the upgrade—unlike in past research studies that overlooked this real-world scenario. This study aimed to investigate the response of preloaded wall-like RC columns after being retrofitted using different configurations. In the experimental campaign, two half-scale columns were cast and axially loaded to 80% of their capacity, and the load was then totally released. After that, these specimens were strengthened with two different schemes, and hence, they were concentrically loaded until failure. In both schemes, the section shape was not modified. The first scheme comprised wrapping carbon FRP (fiber-reinforced polymer) sheets together with near-surface mounted (NSM) steel rebars. However, the second technique was composed of wrapping glass FRP (GFRP) sheets together with NSM steel rebars and bolted steel plates. The second scheme was found to be superior to the first one due to the extra confinement provided by the bolted steel plates. This scheme improved the peak load, stiffness, and dissipated energy by 115%, 75%, and 524%, respectively. Other than the testing campaign, nonlinear numerical modeling was undertaken to examine the behavior of tested specimens. The models were utilized to conduct a parametric study, exploring the influence of the percentage of preloading and the amount of load release on the response of columns strengthened with the second scheme. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the static response of prestressed reinforced concrete beams strengthened in their flexure and shear properties using different strengthening techniques, steel plates, and externally bonded woven carbon fiber fabric (WCFF). The experimental work involved testing twenty large-scale prestressed reinforced concrete beams with a length of 3000 mm, and cross-sections measuring 400 mm in height and 200 mm in breadth were cast in the factory and tested in the laboratory. Four beams without prestressing served as the reference beams; two unbonded pre-tensioned beams served as the control beams, and the remaining fourteen beams were strengthened with steel plates and externally bonded woven carbon fiber fabric (WCFF). Eight of the beams were strengthened with 4 mm thick steel plates and tested under a monotonically increasing load with manual readings recorded. The remaining six beams were strengthened with 0.5 mm thick WCFF and tested under a monotonically increasing load with manual readings recorded. The variables considered included the strengthening techniques (FRP composite sheets, steel plates), the types of strengthening (slices, U-shaped), and the flexural and shear capacities of the strengthened beams. All the implemented strengthening techniques yielded enhancements in both the flexural and shear strength outcomes of the beams compared to their respective controls. The most significant increase in load capacity, whether in terms of ultimate load or first crack load, for the prestressed concrete beams' flexure properties occurred when strengthening with U-shaped steel plates. Additionally, the greatest reduction in deflection at the point of reaching the maximum load for the prestressed concrete beams, in terms of their flexure properties, was observed when strengthening with U-shaped steel plates. Similarly, the maximum load increase for the prestressed concrete beams, in terms of their shear properties, was achieved through strengthening with U-shaped woven carbon fiber fabric wrapping. Furthermore, a finite element model was created to simulate various experimental specimens. The finite element model's results exhibited harmony with the experimental results, affirming the efficacy of the presented finite element model. [ABSTRACT FROM AUTHOR]

During the 16th and 17th centuries, Latin American cities adopted earthen construction techniques from European colonizers. As a result, rammed earth (RE) buildings now occupy an important place in Latin America's cultural heritage. However, earthquakes around the world have shown that unreinforced earthen constructions are highly vulnerable. For several years, researchers in northern South America have been proposing a technique that consists of installing confining steel plates (or wooden elements) on both sides of the RE walls to form a grid. This system has shown excellent performance in controlling seismic damage and increasing strength and ductility capacity. Although researchers have tested full-scale one- and two-story earthen walls under pseudo-static loading in the laboratory, and one- and two-story earthen walls at 1:1 and 1:2 scales on uniaxial and biaxial shaking tables, the behavior of a complete reinforced module (one- or two-story) on a shaking table has never been assessed. The present study presents the results of shaking table tests performed on two-story RE modules at 1:4 scale. The experimental data indicate that the retrofit system with confining steel plates was effective in reducing the seismic damage of earthen constructions. In addition, the comparison of the results of the 1:4 scale tests with the 1:2 and 1:1 scale tests previously conducted by the researchers shows that the acceleration levels of the equivalent prototypes are in the same order of magnitude for the three scales. [ABSTRACT FROM AUTHOR]

The progressive collapse of flat plate structures due to brittle punching shear failure of reinforced concrete (RC) slab-column connections is a major concern in structural engineering. This paper proposed an innovative star-shaped steel plates (SSPs) system to achieve an effective yet practical enhancement of the punching and post-punching performance of RC slab-column connections. SSPs were fabricated from thin steel plates, welded together, and placed in the centre of the joint. Engineering cementitious composite (ECC) was also adopted to replace the joint core concrete and work with the SSPs further to improve the punching shear behaviour of the joint. To evaluate the effectiveness of the proposed system, five large-scale RC slab-column connections with different SSPs configurations and concrete materials were tested under monotonic load. The results showed that the initial stiffness of the joint was minimally affected by the presence of SSPs, but the system significantly improved the punching shear strength, post-punching load-bearing capacity, and deformation capacity of the joint. Specimens with ECC and SSPs exhibited an even higher punching shear strength and more ductile post-punching behaviour. The study also found that the optimum enhancement of the punching shear behaviour of the slab-column joint can be realised when the SSPs yield just before the joint experiences punching shear damage. Finally, formulas were developed to reasonably predict the punching shear strength and post-punching load-carrying capacity of the SSPs reinforced slab-column connections.

In this research, in addition to ensuring the accuracy of the numerical simulations, a 3D reinforced concrete column is numerically modeled in three conditions, including a non-retrofitted state, as well as two states retrofitted with steel plates and CFRP. The coupled temperature-displacement analysis of these columns is conducted under cyclic lateral loading in various heat levels, and the effects of both the retrofits and heat on the cyclic lateral behavior of the columns are studied and compared. According to the results of the study, with temperature rise, both lateral forces and energies increase in the non-retrofitted column, the column retrofitted with steel plates, and the column retrofitted with FRP. This is even more significant at 500°C, particularly in retrofitted columns with steel plates. Besides, retrofitting the columns with steel plates (compared to FRP plates) causes a more substantial increase in the heat sensitivity of the column during cyclic lateral loading. [ABSTRACT FROM AUTHOR]

The buckling "General Method" of EN 1993‐1‐1 and EN 1993‐1‐5 can be applied to solve problems characterized by non‐uniform geometries and complex stress fields. A typical example occurs during the incremental launching of bridge girders with slender web panel subjected to patch loading. However, this method does not explicitly provide the most critical verification point of a structural element and does not allow to consider the mechanical interaction between instability modes. The objective of the study is the development of a novel methodology that can solve these important special design issues, using a completely automatic process by linear static and linear buckling analyses only. The procedure provides the definition of a slenderness parameter for each point of the structure, in order to avoid the nonlinear analyses with imperfections permutation (as described in Annex C of EN 1993‐1‐5) that require a high computational effort. This pointwise slenderness parameter indicates not only where the slenderness is maximum in each buckling mode, but also the slenderness in other points of the structural elements. This would allow to consider the interaction between global and local buckling, with the definition of an equivalent slenderness parameter for buckling modes coupling. [ABSTRACT FROM AUTHOR]

Residual stresses strongly influence the load‐bearing capacity of steel members under compressive axial loads. Current developments in steel and steel‐concrete composite structures imply the use of high‐strength steel grades up to 960 MPa. For such steel plates, only limited results of residual stress investigations are known so far. The authors have applied two established measuring methodologies like the sectioning method and X‐ray diffraction to determine the residual stress state of 40 mm thick steel plates and different widths. The results show that the distribution and amount of longitudinal residual stresses are mainly determined by the oxyfuel‐cutting procedure used to manufacture the specimens. The distribution over the thickness could be determined by X‐ray diffraction. Compared to the results of examinations on lower‐grade steel plates an assumed correlation of residual stresses and steel grades could not be observed. Consequently, residual stresses have a reduced influence on the load‐bearing capacities of structures prone to buckling as the ratio of yield strength to residual stress states declines significantly. [ABSTRACT FROM AUTHOR]

Fault prediction is a vital task to decrease the costs of equipment maintenance and repair, as well as to improve the quality level of products and production efficiency. Steel plates fault prediction is a significant materials science problem that contributes to avoiding the progress of abnormal events. The goal of this study is to precisely classify the surface defects in stainless steel plates during industrial production. In this paper, a new machine learning approach, entitled logistic model tree (LMT) forest, is proposed since the ensemble of classifiers generally perform better than a single classifier. The proposed method uses the edited nearest neighbor (ENN) technique since the target class distribution in fault prediction problems reveals an imbalanced dataset and the dataset may contain noise. In the experiment that was conducted on a real-world dataset, the LMT forest method demonstrated its superiority over the random forest method in terms of accuracy. Additionally, the presented method achieved higher accuracy (86.655%) than the state-of-the-art methods on the same dataset. [ABSTRACT FROM AUTHOR]

Abstract To accurately predict the strength of concrete in a combined structure, this paper analyzed the effect of steel plates on the pore structure and strength of concrete. Two concrete strengths and eight steel plate thicknesses were used for the experimental specimens, and their pore structures and strengths were tested at 3, 7, and 28 days. It was found that the pore structure of concrete increased with the increase in steel plate thickness. Additionally, the strength of concrete decreased with the increase in steel plate thickness. Besides, an equation was proposed to predict the strength of concrete in specimens with steel plates in this research.

These elements are innovative and of interest to many researchers for the reinforcement of wooden elements. For the reinforced beam elements, the effect of the reinforcement factor, FRP and steel elastic modulus or FRP and steel arrangement of the reinforcement on the performance of the flexural elements was determined, followed by reading the load-displacement diagram of the reinforced beam elements. The finite element model was then developed and verified with the experimental results, which was mainly related to the fact that the general theory took into account the typical tensile failure mode, which can be used to predict the flexural strength of reinforced timber beams. From the tests, it was determined that reinforced timber beam elements had relatively ductile flexural strengths up to brittle tension for unreinforced elements. As for the reinforcements of FRP, the highest increase in load-bearing capacity was for carbon mats at 52.47%, with a reinforcement grade of 0.43%, while the lowest was for glass mats at 16.62% with a reinforcement grade of 0.22%. Basalt bars achieved the highest stiffness, followed by glass mats. Taking into account all the reinforcements used, the highest stiffness was demonstrated by the tests of the effectiveness of the reinforcement using 3 mm thick steel plates. For this configuration with a reinforcement percentage of 10%, this increase in load capacity was 79.48% and stiffness was 31.08%. The difference between the experimental and numerical results was within 3.62–27.36%, respectively. [ABSTRACT FROM AUTHOR]

In order to improve the seismic performance of glued-laminated timber frames, the low-cycle loading tests of four timber buckling-restrained braces (TBRB) are carried out. The mechanical properties, failure modes, hysteresis curves, ductility, and energy dissipation capacity of timber buckling-restrained braces are analyzed. The test results showed that the failure modes of the specimens include the tensile failure of steel core, local buckling of steel core and local compression failure of timber, multi-wave buckling of steel core and crack of timber. The hysteretic curve of each specimen has a typical fusiform shape, which means TBRB have good energy dissipation capacity and large initial stiffness. The ductility and energy dissipation capacity of TBRB strengthened with steel plates and end-reinforced hoop are significantly improved, compared to the TBRB without being strengthened. The test results show that TBRB strengthened with steel core plates and end-reinforced hoop can achieve better seismic performance, which reveals the application prospect in seismic design of glued-laminated timber frames. [ABSTRACT FROM AUTHOR]

Experimental investigations on novel composite columns with a concrete filled hollow section and high‐strength steel plates as core in ambient and fire conditions High‐performance composite columns are commonly carried out with solid steel sections as core profiles. These profiles imply limitations due to reductions of the yield strength depending on the thickness and high residual stresses. In this publication, the authors present a novel section consisting of a concrete filled circular hollow section with locally connected steel plates as core. To increase the load bearing capacity, steels with yields strengths up to 960 N/mm2 are used. Experimental investigations for ambient conditions and in case of fire are presented. The columns showed a promising load bearing behaviour. These investigations will serve as basis for a systematic development of this innovative, high‐performance composite column with a corresponding design concept. [ABSTRACT FROM AUTHOR]

Welded lap joints play a vital role in a wide range of engineering structures such as pipelines, storage tanks, pressure vessels, and ship hulls. This study aims to investigate the propagation of ultrasonic guided waves in steel welded lap joints for the baseline-free inspection of joint defects using the mode conversion of Lamb waves. The finite element method was used to simulate a single lap joint with common defects such as corrosion and disbonding. To identify the propagating wave modes, a wavenumber–frequency analysis was conducted using the 2D fast Fourier transform. The power loss of the transmitted modes was also determined to identify damage in the lap joints. The results indicate that the A0 incident in pristine conditions experienced significant transmission losses of about 9.5 dB compared to an attenuation of 2.8 dB for the S0 incident. The presence of corrosion was found to reduce these transmission losses by more than 28%. In contrast, introducing disbonding in the lap joint increased the transmission loss of the S0 incident, while a negligible loss was observed for the A0 incident. The mode-converted S0 (MC-S) and mode-converted A0 (MC-A0) incidents were found to exhibit a unique sensitivity to the presence of corrosion and disbonding. The results indicate that MC-S0 and MC-A0 as well as Lamb mode incidents interact differently in terms of corrosion and disbonding, providing a means to identify damage without relying on baseline signals.

This study aimed to evaluate the static response of prestressed reinforced concrete beams strengthened in their flexure and shear properties using different strengthening techniques, steel plates, and externally bonded woven carbon fiber fabric (WCFF). The experimental work involved testing twenty large-scale prestressed reinforced concrete beams with a length of 3000 mm, and cross-sections measuring 400 mm in height and 200 mm in breadth were cast in the factory and tested in the laboratory. Four beams without prestressing served as the reference beams; two unbonded pre-tensioned beams served as the control beams, and the remaining fourteen beams were strengthened with steel plates and externally bonded woven carbon fiber fabric (WCFF). Eight of the beams were strengthened with 4 mm thick steel plates and tested under a monotonically increasing load with manual readings recorded. The remaining six beams were strengthened with 0.5 mm thick WCFF and tested under a monotonically increasing load with manual readings recorded. The variables considered included the strengthening techniques (FRP composite sheets, steel plates), the types of strengthening (slices, U-shaped), and the flexural and shear capacities of the strengthened beams. All the implemented strengthening techniques yielded enhancements in both the flexural and shear strength outcomes of the beams compared to their respective controls. The most significant increase in load capacity, whether in terms of ultimate load or first crack load, for the prestressed concrete beams’ flexure properties occurred when strengthening with U-shaped steel plates. Additionally, the greatest reduction in deflection at the point of reaching the maximum load for the prestressed concrete beams, in terms of their flexure properties, was observed when strengthening with U-shaped steel plates. Similarly, the maximum load increase for the prestressed concrete beams, in terms of their shear properties, was achieved through strengthening with U-shaped woven carbon fiber fabric wrapping. Furthermore, a finite element model was created to simulate various experimental specimens. The finite element model’s results exhibited harmony with the experimental results, affirming the efficacy of the presented finite element model.

In the Middle East, wall-like reinforced concrete (RC) columns are a common choice in multistory buildings. Sometimes, these columns need axial retrofitting for increased load capacity. In practice, unstrengthened columns bear their load, and if retrofitting is necessary, the load is released before the upgrade—unlike in past research studies that overlooked this real-world scenario. This study aimed to investigate the response of preloaded wall-like RC columns after being retrofitted using different configurations. In the experimental campaign, two half-scale columns were cast and axially loaded to 80% of their capacity, and the load was then totally released. After that, these specimens were strengthened with two different schemes, and hence, they were concentrically loaded until failure. In both schemes, the section shape was not modified. The first scheme comprised wrapping carbon FRP (fiber-reinforced polymer) sheets together with near-surface mounted (NSM) steel rebars. However, the second technique was composed of wrapping glass FRP (GFRP) sheets together with NSM steel rebars and bolted steel plates. The second scheme was found to be superior to the first one due to the extra confinement provided by the bolted steel plates. This scheme improved the peak load, stiffness, and dissipated energy by 115%, 75%, and 524%, respectively. Other than the testing campaign, nonlinear numerical modeling was undertaken to examine the behavior of tested specimens. The models were utilized to conduct a parametric study, exploring the influence of the percentage of preloading and the amount of load release on the response of columns strengthened with the second scheme.

This paper presents the report of two groups of experimental works to study the shear capacity and strain distribution of reinforced concrete beams strengthened on beam sides with the near-surface mounted (NSM) method. One group was strengthened with steel bars, and the other was strengthened with steel plates. Each group consisted of three control beams and six strengthened beams. Steel bars or plates were installed vertically or diagonally at an angle of 45°. The total number of reinforced concrete beam specimens tested in this study was 18. All beams tested were simply supported and monotonically loaded with two concentrated loads. The longitudinal reinforcement ratio was used as a test variable to attain differences in the required shear demand. An analytical study using the two-dimensional finite element method was carried out to observe the strain distribution along the length of the beams. In the finite element model strengthening on the beam side for either steel bars or plates was modeled with line segments as transversal reinforcement, and the bond between concrete and strengthening materials is assumed to be perfect. The complete flexural response of the cross-section due to bending was also analyzed using the fiber element method. The test results show that some of the specimens strengthened with steel bars or plates achieved flexural capacity, and others experienced a sudden failure due to shear. The analysis results using the finite element method predict well the test results for beams that fail in the flexural mode and on beams with shear failure mode before the failure occurs. The analysis results also show significant differences in the strain distribution between beams without and with strengthening. The orientation of the angle of installation of steel bars or plates and the ratio of longitudinal reinforcement also affect the strain distribution along the beam length. In addition, the fiber element method can satisfactorily predict the tested beams' flexural behavior.

This work aims to provide an effective structural solution, minimizing the discomfort during the works' execution, for how to retrofit the Day-Hospital building of the National Cancer Institute "G. Pascale Foundation" in Naples. The structural vulnerability has been preliminarily evaluated for this scope, using linear static and dynamic analyses according to code provisions. The performance index in terms of peak ground acceleration (PGA), both for the life safety (SLV) limit state and the operational (SLO) limit state, has been evaluated. A seismic assessment has been performed by finite element (FE) analyses using the SAP2000 computer program, post-processor VIS15 and plugin SPF. Two main solutions have been proposed to improve the structural performance of the existing building. The first one is based on increasing the thickness of the existing reinforced concrete (RC) cores. The second solution is characterized by strengthening the RC cores using steel plates, steel strips and angles. A comparison of the proposed interventions is provided herein from the technological and financial standpoints. [ABSTRACT FROM AUTHOR]

During the 16th and 17th centuries, Latin American cities adopted earthen construction techniques from European colonizers. As a result, rammed earth (RE) buildings now occupy an important place in Latin America’s cultural heritage. However, earthquakes around the world have shown that unreinforced earthen constructions are highly vulnerable. For several years, researchers in northern South America have been proposing a technique that consists of installing confining steel plates (or wooden elements) on both sides of the RE walls to form a grid. This system has shown excellent performance in controlling seismic damage and increasing strength and ductility capacity. Although researchers have tested full-scale one- and two-story earthen walls under pseudo-static loading in the laboratory, and one- and two-story earthen walls at 1:1 and 1:2 scales on uniaxial and biaxial shaking tables, the behavior of a complete reinforced module (one- or two-story) on a shaking table has never been assessed. The present study presents the results of shaking table tests performed on two-story RE modules at 1:4 scale. The experimental data indicate that the retrofit system with confining steel plates was effective in reducing the seismic damage of earthen constructions. In addition, the comparison of the results of the 1:4 scale tests with the 1:2 and 1:1 scale tests previously conducted by the researchers shows that the acceleration levels of the equivalent prototypes are in the same order of magnitude for the three scales.

Steel plates are used in the construction of various structures in civil engineering, aerospace, and shipbuilding. One of the main failure modes of plate members is buckling. Openings are provided in plates to accommodate various additional facilities and make the structure more serviceable. The present study examined the critical buckling load of rectangular steel plates with centrally placed circular openings and different support conditions. Various datasets were compiled from the literature and integrated into artificial intelligence techniques like Gene Expression Programming (GEP), Artificial Neural Network (ANN) and Evolutionary Polynomial Regression (EPR) to predict the critical buckling loads of the steel plates. The comparison of the developed models was conducted by determining various statistical parameters. The assessment revealed that the ANN model, with an R2 of 98.6% with an average error of 10.4%, outperformed the other two models showing its superiority in terms of better precision and less error. Thus, artificial intelligence techniques can be adopted as a successful technique for the prediction of the buckling load, and it is a sustainable method that can be used to solve practical problems encountered in the field of civil engineering, especially in steel structures. [ABSTRACT FROM AUTHOR]

In the last decades the buckling of steel members in fire has attracted the attention of the scientific community, but considerations about the choice of the initial imperfections have been rarely the focus of scientific publications. However, initial imperfections play a primary role in the definition of the resistance, especially when local buckling is investigated. Although the lowest buckling mode is usually employed, the definition of an appropriate imperfection shape providing, for instance, the lowest resistance is not straightforward. Even more so when the local behaviour at elevated temperatures is being studied, since the buckling behaviour may differ from the one at ambient temperature, owing to the steel degradation and possible load redistributions. In this paper steel plates in compression at elevated temperatures are studied considering different shapes of imperfection. A parametric analysis on webs and flanges composing Class 4 HE and IPE sections with S355 steel grade is presented, considering five temperatures in a relevant range (400–800°C) and several plate aspect ratios. The influence of the imperfection shapes on the resistance depending on the temperature, the length and the slenderness of the web and flange plates is discussed. [ABSTRACT FROM AUTHOR]

Fault prediction is a vital task to decrease the costs of equipment maintenance and repair, as well as to improve the quality level of products and production efficiency. Steel plates fault prediction is a significant materials science problem that contributes to avoiding the progress of abnormal events. The goal of this study is to precisely classify the surface defects in stainless steel plates during industrial production. In this paper, a new machine learning approach, entitled logistic model tree (LMT) forest, is proposed since the ensemble of classifiers generally perform better than a single classifier. The proposed method uses the edited nearest neighbor (ENN) technique since the target class distribution in fault prediction problems reveals an imbalanced dataset and the dataset may contain noise. In the experiment that was conducted on a real-world dataset, the LMT forest method demonstrated its superiority over the random forest method in terms of accuracy. Additionally, the presented method achieved higher accuracy (86.655%) than the state-of-the-art methods on the same dataset.

Abundant research has been presented addressing the strengthening of continuous reinforced concrete (RC) beams depending on the moment-redistribution (MR) effect. Most of the research was backed on either strengthening the bottom surface of the beam or both the top and bottom surfaces. As such, both techniques require full accessibility for the beam bottom surface, which may not be applicable. This paper presents a novel strengthening technique using near-surface mounted steel or fiber-reinforced polymer (FRP) laminates. The present study assesses experimentally/numerically the behavior of RC continuous beams top-strengthened at the hogging regions only. The experimental process includes testing five full-scale RC continuous beams strengthened with either steel plates or carbon-fiber-reinforced polymer (CFRP) laminates. Moreover, the numerical model is developed using a finite element (FE) program and used for parametric investigation to assess the strengthening efficiency under different parameters. Strengthening using glass fiber-reinforced polymer (GFRP) laminates was also investigated in the numerical analysis. Strengthening using steel plates caused up to fifty percent moment redistribution with a significant increase in the load-carrying capacity of the beams. On the other hand, CFRP- and GFRP-strengthened beams showed substantial amounts of moment redistribution without significantly affecting the load-carrying capacity. [ABSTRACT FROM AUTHOR]

Steel plates with openings are among the important ship structural components used in the ship's hull to withstand the hydrostatic forces of the ocean, which cause sagging and hogging moments at the ship's bottom. The existence of openings on plates can cause structural rupture, stress concentration and a decrease in ultimate strength. This research is aimed at investigating the influence of selected parameters on the ultimate capacity of steel plates with rectangular holes subjected to axial stress, using ANSYS finite element analysis (FEA) under its non-linear static structural programme. The main parameters investigated in this paper are the plate thickness, opening aspect ratio, number of openings, position of openings, and the boundary condition of the plate. The influence of these parameters on the stress of plates and their deformation was evaluated. The comparison of the numerical simulation with the well-established analytical method using the Navier solution and Roark's Formulas showed a good agreement. [ABSTRACT FROM AUTHOR]

In general, plates are classified as thick plates when the minimum dimension to thickness ratio (b/h) is less than 10, thin plates when the b/h ratio ranges from 10 to about 100, provided that the plate maximum deflection to thickness ratio (w/h) is less than 0.2, and membranes when the b/h ratio approaches 100 and w/h ≥ 0.2. Thick plates develop internal stress resultants governed by three-dimensional elasticity similar to that of a solid body. Thin plates behave as plane stress members governed by two-dimensional elasticity. Membranes can only develop internal tensile stress within the plate’s neutral plane. Few studies have adopted b/h ratios between 90 and 110 to investigate the feasibility of the utilization of such plates in their various available forms. The current study with the b/h ratio of 100 aims to fill the gap. Steel Plates are available in different forms such as intact plates, stiffened, perforated, and stiffened perforated plates. They are used in buildings, bridges, ships, as well as aerospace structures. In this study, the investigated steel plate has a square shape and is subjected to uniaxial loading. The plate edges are simply supported. The plate is 200 mm wide and 2 mm thick. In this case, the critical buckling strength is, in general, less than the plate maximum strength. With further loading, the plate would experience an undesirable sudden mode of failure owing to buckling instability. This study aims at investigating the performance of the different forms of square steel plates, such as intact, stiffened, perforated, and perforated stiffened, when the minimum dimension to thickness ratio is 100. A pushover finite element linear elastic buckling analysis as well as a nonlinear large deflection buckling analysis have been carried out. The study indicated that the increase in the plate maximum strength in single, double, and triple stiffener plates was 75.6%, 174%, and 196%, respectively, compared to that of the intact plate. Based on the obtained results, it is concluded that the utilization of plates having the b/h ratio of 100 is feasible provided that the appropriate plate form is adopted.

Different welding cooling methods used in steel manufacturing confer different mechanical properties to the produced material. The use of the electric arc-type welding connections generates extremely high temperatures that alter the mechanical properties of the steel and also the ability of the steel to resist applied loads. Therefore, in the present study, experiments were conducted to investigate the properties of 24 specimens of standard steel plates that were cooled using different methods after the welding process. The experimental results revealed that gradual cooling through the air after the welding process exerted a negative effect on the mechanical properties of the steel material. This was evident in the values of the yield stress, ultimate stress, and modulus of elasticity, which were reduced by a factor of 11.8%, 8.4%, and 7.0%, respectively, for the specimens with a thickness of 2 mm, and by 13.8%, 12.7%, and 5.2%, respectively, for the specimens with a thickness of 5 mm. On the contrary, the process of rapid cooling using water exerted a positive influence on the mechanical properties of the steel material, which manifested as enhanced values of all mechanical properties. Moreover, the welding efficiency achieved using different cooling processes decreased with the increase in the thickness of the steel plate. It is noteworthy that the negative impact of cooling in the air on the mechanical properties of the produced steel is not considered in the current design codes.

Distance measuring between two metal plates by γ-ray backscattering is a new method that is applicable for different industries, especially the oil, gas, and petrochemical industry. In the present work, 2, 6, and 10 mm thick steel plates were used as thin, medium, and thick plates to perform the experiments. Also, two sources of 137Cs and 60Co have been used to show the effect of source energy on the accuracy of the measurements. The results showed that the distance measurement depends on the Gamma-ray energy, and for the same measurement accuracy, the Gamma source with higher energy would be more applicable for measuring the distance between two steel plates. Moreover, it was found that increasing the γ-ray energy will increase the accuracy of the measurement. In addition to the energy of the gamma source, the distance measurement depends on the thickness of the two plates, the arrangement of the thicker plate comparing to the thinner ones, and the distance between them. Finally, increasing the distance between the plates leads to reducing the measurement accuracy, which was calculated to be one centimeter.

This paper presented a strengthening technique for enhancement reinforced concrete (RC) slab-column connection behavior using steel plates and steel stiffeners. A bi-axial load was applied with an eccentricity of 150 mm in both x and z directions. Four specimens with dimensions of 1,600 × 1,600 × 100 mm were tested in this research. The steel plate dimensions were chosen to be 600 × 600 and 800 × 800 mm with 6 mm thickness. The steel stiffeners are used to support and enhance the steel plate that it is extended from column to the slab-column connection with different dimension. The results showed an improvement in the stiffness of slab and increasing in the ultimate capacity. Also, when the steel plates dimensions increased, the ultimate capacity and stiffness increased.

• A novel 3D peridynamic model is developed to examine fractures in steel plates. • The 3D peridynamic model is well-validated with experiments in several conditions. • The 3D peridynamic model overpasses mesh-based models in efficiency and accuracy. • The fracture behavior of steel shifts from ductile to brittle with moment and torsion. • The proposed model can be used in the design optimization of steel plates. Steel plates are widely used in construction to connect different structural elements using welding or bolts. The fracture in these plates may lead to catastrophic consequences such as structural collapse. The paper investigates steel plates' deformation capacity and fracture behavior in bolted connections in three-dimensional (3D) flexibility. The peridynamic method is utilized to model the excessive deformation and fracture of steel plates in bolted connections when they are influenced by shear, moment, and torsion. The mesh-free nature of peridynamics enables modeling the extreme deformation and fracture in ductile materials such as steel. We validate the 3D peridynamic model by comparing its fracture and deformation results with experimental measurements and observations in several loading and boundary conditions. The paper highlights the following novelties: (1) a new and highly efficient 3D peridynamic model is proposed to model fractures in steel plates when exposed to combined actions of shear, moment, and torsion simultaneously; (2) the proposed 3D peridynamic model overcomes the difficulties faced by the mesh-based methods in modeling excessive deformation in ductile materials such as steel; (3) the study also reveals a shift in the fracture behavior of steel plates from ductile to brittle when exposed to high values of moment and torsion. This shift in fracture behavior has not been thoroughly addressed, impacting the integrity of steel structures and the warning stage for yielding. Overall, utilizing the 3D peridynamic model as a modeling and simulation tool can help engineers and researchers examine the behavior of steel plates under various loading conditions, thus allowing for optimization of the design of steel plates used widely in steel construction. [Display omitted] [ABSTRACT FROM AUTHOR]

• Study the bond behavior of CFRP-repaired steel plates with initial debonding defects. • A strip-based numerical method using the explicit 4th-order Runge-Kutta technique was proposed. • Single-lap shear test was simulated via FEM combined with cohesive zone modeling. • The effects of bond lengths and defect locations were discussed. In recent years, carbon fiber-reinforced polymers (CFRP) have earned extensive attention in the field of structural rehabilitation. Adhesive bonding, as a prevalent technique, plays a crucial role in utilizing CFRP for strengthening steel structures. Nevertheless, debonding defects, commonly arising within the bond region between CFRP and host structures, hold the potential to induce the premature debonding failure of adhesively bonded joints. As a result, this research attempts to propose a strip-based numerical method using the explicit 4th-order Runge-Kutta technique (strip-based RK4) to investigate the full-range bond behavior of CFRP-to-steel single-lap joints with multiple arbitrary debonding defects. Also, three-dimensional (3D) finite element models (FEMs) of fully bonded single-lap joints were established in conjunction with cohesive zone modeling (CZM) to simulate the single-lap shear test reported in literature, based on which joints containing debonding defects were further modeled. Predictions from the proposed methodology were subsequently compared with test results and FE analysis to confirm its accuracy. Thereafter, the parametric analysis was carried out to investigate the effects of parameters, including bond length and defect position, on the bond behavior of the single-lap joint. The results indicate that the proposed strip-based RK4 method is accurate, with errors within 2% compared to FE analysis, and computationally efficient, with runtime being less than 50% of FE analysis. The findings of this study can be used as a guide for the design or damage assessment of CFRP-repaired structures in the future. [ABSTRACT FROM AUTHOR]

These elements are innovative and of interest to many researchers for the reinforcement of wooden elements. For the reinforced beam elements, the effect of the reinforcement factor, FRP and steel elastic modulus or FRP and steel arrangement of the reinforcement on the performance of the flexural elements was determined, followed by reading the load-displacement diagram of the reinforced beam elements. The finite element model was then developed and verified with the experimental results, which was mainly related to the fact that the general theory took into account the typical tensile failure mode, which can be used to predict the flexural strength of reinforced timber beams. From the tests, it was determined that reinforced timber beam elements had relatively ductile flexural strengths up to brittle tension for unreinforced elements. As for the reinforcements of FRP, the highest increase in load-bearing capacity was for carbon mats at 52.47%, with a reinforcement grade of 0.43%, while the lowest was for glass mats at 16.62% with a reinforcement grade of 0.22%. Basalt bars achieved the highest stiffness, followed by glass mats. Taking into account all the reinforcements used, the highest stiffness was demonstrated by the tests of the effectiveness of the reinforcement using 3 mm thick steel plates. For this configuration with a reinforcement percentage of 10%, this increase in load capacity was 79.48% and stiffness was 31.08%. The difference between the experimental and numerical results was within 3.62–27.36%, respectively.

The paper describes field test results of 7.62 × 51 mm M61 AP (armour piercing) ammunition fired into mild steel targets at an outdoor range. The targets varied from 10 mm to 32 mm in thickness. The tests recorded penetration depth, probability of perforation (i.e., complete penetration), muzzle and impact velocities, bullet mass, and plate yield strength and hardness. The measured penetration depth exhibited a variability of approximately ±12%. The paper then compared ballistic test results with predictive models of steel penetration depth and thickness to prevent perforation. Statistical parameters were derived for muzzle and impact velocity, bullet mass, plate thickness, plate hardness, and model error. A Monte-Carlo probabilistic analysis was then developed to estimate the probability of plate perforation of 7.62 mm M61 AP ammunition for a range of impact velocities, and for mild steels, and High Hardness Armour (HHA) plates. This perforation fragility analysis considered the random variability of impact velocity, bullet mass, plate thickness, plate hardness, and model error. Such a probabilistic analysis allows for reliability-based design, where, for example, the plate thickness with 95% reliability (i.e. only 1 in 20 shots will penetrate the wall) can be estimated knowing the probabilistic distribution of perforation. Hence, it was found that the plate thickness to ensure a low 5% probability of perforation needs to be 11–15% thicker than required to have a 50/50 chance of perforation for mild steel plates. Plates would need to be 20–30% thicker if probability of perforation is reduced to zero.

Based on the software Visual-Environment, Finite element method (FEM) was performed on the dissimilar butt-joint between Q345 and 2Cr13 steel aiming at the welding residual stress. The main contents in the paper were different current intensity was applied to modeling the welding process of Q345/2Cr13 dissimilar steel and the law of residual stress field were discussed. Based on the result, different current intensities have little effect on the lateral residual stress, while the longitudinal residual stress and the initial and end of the weld have a great influence. The physical properties of the dissimilar plates lead to uneven distribution of residual stress, and the current intensity should be smaller.

Steel greenhouse structures are generally constructed by individual sole contractors using quick empirical structural calculations (pre-engineered solutions). It is also common to import standard greenhouses from other countries, mainly from The Netherlands, Italy, and France, and sometimes from Great Britain and Israel. Evidently, these countries differ concerning the local wind and snow conditions. Therefore, there is a need for a better design of structures accepted as satisfactory, while installation can be done in a different location. Many greenhouse structures incorporating poor designs or inappropriate pre-engineered solutions are currently in use. At the same time, demolition and reconstruction represent a very expensive solution considering the loss of crop production and the demolition and construction costs; thus, strengthening is a reasonable alternative. This paper presents strengthening techniques for steel greenhouses that are code-deficient according to EN 13031 and Eurocodes. Consequently, two case studies are presented as typical applications of greenhouse structure strengthening.

This work aims to provide an effective structural solution, minimizing the discomfort during the works’ execution, for how to retrofit the Day-Hospital building of the National Cancer Institute “G. Pascale Foundation” in Naples. The structural vulnerability has been preliminarily evaluated for this scope, using linear static and dynamic analyses according to code provisions. The performance index in terms of peak ground acceleration (PGA), both for the life safety (SLV) limit state and the operational (SLO) limit state, has been evaluated. A seismic assessment has been performed by finite element (FE) analyses using the SAP2000 computer program, post-processor VIS15 and plugin SPF. Two main solutions have been proposed to improve the structural performance of the existing building. The first one is based on increasing the thickness of the existing reinforced concrete (RC) cores. The second solution is characterized by strengthening the RC cores using steel plates, steel strips and angles. A comparison of the proposed interventions is provided herein from the technological and financial standpoints.