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Recycling of concrete generated from construction and demolition waste as coarse aggregates in concrete has been a focus of several studies for the evolution of the green concrete and conservation of natural resources. This investigation, therefore, focusses on the study of the behavior of RC beams strengthened with externally bonded CFRP wraps, cast with both natural and recycled aggregates concrete. Furthermore, one-way slabs were strengthened with Near Surface Mounted (NSM) bars, while two-way slabs were strengthened with CFRP strips. One-way and two-way slabs used in the study were cast with both natural and recycled aggregate concrete (RAC). In RAC, natural aggregates were replaced by 30% recycled concrete aggregates. All beams and slabs were cast with concrete mix design of 1:1.24:2.6 and w/c ratio of 0.43. Beams and one-way slabs, control and strengthened, were tested under four-point bending. Whereas, two-way slabs were tested in punching. A significant increase in the load-carrying capacity was observed for both natural and recycled aggregates concrete beams without shear reinforcement and two-way slabs, indicating the effectiveness of strengthening scheme. Increase of 20.5% and 12.6%, respectively, was found in the load-carrying capacities for the cases of both and natural and RAC beams with natural aggregate concrete (NAC) and RAC beams when results were compared for the case of shear deficient control and strengthened RC beams with CFRP wraps. Furthermore, increase of 27 − 37% was noted in load-carrying capacities of both natural and RAC two-way slabs when results were compared for the case of control and strengthened NAC and RAC slabs. [ABSTRACT FROM AUTHOR]

Secondary cooling electromagnetic stirring (S-EMS) significantly impacts the internal quality of continuous casting slabs. In order to investigate the effects of S-EMS modes on segregation in slabs, a three-dimensional numerical model of the full-scale flow field, solidification, and mass transfer was established. A comparative analysis was conducted between continuous electromagnetic stirring and alternate stirring modes regarding their impacts on steel flow, solidification, and carbon segregation. The results indicated that adopting the alternate stirring mode was more advantageous for achieving uniform flow fields and reducing the disparity in solidification endpoints, thus mitigating carbon segregation. Specifically, the central carbon segregation index under continuous stirring at 320 A was 1.236, with an average of 1.247, while under alternate stirring, the central carbon segregation index decreased to 1.222 with an average of 1.227. [ABSTRACT FROM AUTHOR]

Reinforced concrete (RC) slabs often require strengthening due to deterioration, increased loads, or design changes. Concrete overlay is a commonly used technique for strengthening, but predicting the behavior of overlays can be challenging. To address this challenge, this study presents a three-dimensional non-linear finite element model using Abaqus/CAE to analyze the structural performance of one-way reinforced concrete (RC) slabs strengthened with concrete overlays. The model considers three different bonding conditions at the interface: friction, epoxy, and shear connectors. The predictions of the model were compared to experimental results, and it was found that the model accurately captures the load–deflection response, cracking behavior, and interfacial slip in the strengthened slabs. Additionally, the model accurately predicts the new structural capacity of the strengthened slabs, showing good agreement with experimental data. These findings offer valuable insights into the effectiveness of concrete overlays as a traditional strengthening technique for RC slabs. Moreover, the developed finite element model provides a useful tool for optimizing the design of these overlays. [ABSTRACT FROM AUTHOR]

This research explores the dynamic responses of reinforced concrete (RC) slabs under high-velocity impacts. The study utilizes advanced numerical simulations to investigate the effects of varied impact loading and slab depths, unveiling complex rate-dependent behaviors (i.e., impact forces, reactions, accelerations, and displacements) across a diverse range of velocities. The alignment of simulation results with experimental data validates the robustness and accuracy of the employed approach. Additionally, an analytical model predicting the load-carrying capacity and deflection of these slabs under high-velocity loads is proposed. The results indicated that higher loading rates correlate with increased forces and damage until perforation. Analytical models exhibit strong performance within a ±10% error margin, and response surface analysis quantifies the impactor velocity's influence on load for a constant thickness. Overall, this investigation sheds light on the dynamic complexities of RC slabs subjected to high-velocity impacts, providing valuable insights for structural design considerations. [ABSTRACT FROM AUTHOR]

Ferrocement is extensively utilized in construction as a structural material, given its exceptional mechanical properties and impact strength. This study aimed to analyze the performance of ferrocement that is reinforced with recycled steel wire tires under static loads. This current study a comparative investigation of behavior of compressive strength of ferrocement cubes and flexural behavior of ferrocement panels and behavior of ferrocement panels reinforced with tire Steel wire tires under static loads. Ferrocement slabs sample was (L 500 x W 500 x t 50mm) in size, and 15 slabs were subjected to static point load. The number of wire mesh layers, which was replaced by recycling tire steel wire as a ratio of the volume of wire mesh, was the main parameter in the current study. The percentage of recycle steel wire tires are 33% and 66% and 99% from of steel wire mesh for reinforcements of ferrocement panels. The results presented, the behavior of panels under static load at ultimate failure and first crack. It showed that ferrocement have 99.0% steel wire tires gave a good performance under static loading which were required to increase the load value to make the first crack and ultimate failure, and causing late of the failure and less deflection. [ABSTRACT FROM AUTHOR]

This study presents the results of an investigation of the effect of biaxial geogrid reinforcement on the load-carrying capacity of rigid pavement slabs. Six concrete slabs having dimensions of 800 × 800 × 50 mm were prepared and tested under static loads at three different locations: interior, edge and corner of the slab. Three of the slabs were unreinforced and taken as references. The other three slabs were reinforced with a biaxial geogrid layer. Study parameters investigated in this study included the load-carrying capacity, ductility and failure modes of the slabs. The experimental results were verified theoretically using the finite-element software ABAQUS. The findings indicated that the load-carrying capacity and ductility of the concrete slabs reinforced with the biaxial geogrid can be improved. Test results obtained indicated that the maximum load-carrying capacity of the concrete slabs reinforced with the biaxial geogrid was increased by 25%, 26% and 29% for interior, edge and corner loading locations, respectively. [ABSTRACT FROM AUTHOR]

A high proportion of the CO2 emissions worldwide are caused by the construction sector or are associated with buildings. Every part of the industry needs to reduce its share of emissions, so the building sector must also do its part. One possible solution for achieving this reduction in the field of load-bearing structures is the use of adaptive structures. This research focuses on adaptive slab structures, which require specific actuators to be integrated into the system. Conventional actuators are not suitable due to the prevailing requirements, namely installation space and performance. For this investigation, the actuator is divided into different functional components. A rough description of the requirements for one component, namely the energy converter, is given. Different concepts are developed, tested, and compared with numerical results. Due to the requirements, the concepts are limited to hydraulics. The authors then present a comparison of different simulation strategies for the energy converter. Overall, this paper provides a new contribution to the design of energy converter concepts for integrated hydraulic actuators in slabs, along with experimental verification of the working principle of the energy converters to meet the requirements. A simplified numerical model is proposed to estimate the behavior of the energy converter during the early design phase. [ABSTRACT FROM AUTHOR]

This paper aims to explore the structural performance of 3D-printed and casted cement-based steel-reinforced concrete beams and one-way slabs incorporating short carbon fibre and activated carbon powder, which have been shown to enhance concrete's flexural strength and reduce its electrical resistivity. The samples are cast and printed in 250 × 325 × 3500 mm beams and 150 × 400 × 3500 mm one-way slabs and mechanical, electrical, and piezoresistivity properties were measured. This length of beams and one-way slabs with rebars have been considered as they can magnify the flexural and cracking behaviour and make them easier to be monitored and analysed. The samples were loaded up to 80% of maximum stress. Crack propagation and strain was assessed using the 2D digital image correlation (DIC) method. The results compared samples under continuously increasing loads between 3D-printed and cast samples. The 3D-printed composites had a better piezoresistive response due to the enhanced anisotropic behaviour. DIC analysis illustrated similar results among different samples, while 3D-printed blocks had lower cracking performance due to the horizontal case fracture in lower stress. [ABSTRACT FROM AUTHOR]

Several existing reinforced concrete structures (RC) require improvement in performance for reasons of deterioration. This is due to many factors such as the change in code requirements. The current study was assisted by experimental models to investigate the behavior of RC slabs strengthened with carbon fiber reinforced polymer (CFRP) laminates and sheets. Seven RC slabs strengthened with CFRP (laminates and sheets) were tested. The slabs were divided into four groups. The first phase includes one slab without strengthening (reference slab), the second phase includes one slab strengthened with CFRP laminates, and the third phase includes one slab strengthened with CFRP sheets. The fourth phase includes four slabs strengthened with different areas of sheets. The major test parameters included the different types of strengthening materials and the corresponding types of epoxies used for each type of CFRP. A comparison between the two types of CFRP was conducted. The load deflection, load strain and mode of failure were investigated. Test results demonstrated that the flexural strength increased, and the ductility reduced with the increase in the area of CFRP sheets. for almost equivalent applied area, CFRP Sheets has more significant influence on the behavior of the strengthened slabs than laminates. Strengthening of RC slabs with CFRP improves the flexural strength capacity for both types. For the same CFRP strength, the sheets showed a cost reduction of 70%. The difference is attributed to the difference in the mechanical properties and the bonding quality of the CFRP material. [ABSTRACT FROM AUTHOR]

Concrete is brittle; hence, it is incredibly likely that concrete buildings may fail in both local and global ways under dynamic and impulsive stresses. An extensive review investigation was carried out to examine reinforced concrete (RC) slab behavior under low-velocity impact loading. Significant past research studies that dealt with experimental and numerical simulations and analytical modeling of the RC slabs under impact loading have been presented in this work. As a result, numerous attempts to define failure behavior and to assess concrete structures' vulnerability to lateral impact loads have been made in the literature. Based on analytical, numerical, and experimental studies carried out in previous research, this article thoroughly reviewed the current state of the art regarding the responses and failure behaviors of various types of concrete structures and members subjected to low-velocity impact loading. The effects of different structural and load-related factors were examined regarding the impact strength and failure behavior of reinforced concrete slabs reinforced with various types of strengthening procedures and exposed to low-velocity impact loads. The reviews suggested that advanced composite materials, shear reinforcement, and hybrid techniques are promising for effectively strengthening concrete structures. [ABSTRACT FROM AUTHOR]

This study aims to investigate the flexural behavior of high-strength thin slabs externally strengthened with fiber-reinforced polymer (FRP) laminates through a numerical simulation. A three-dimensional (3D) finite element (FE) model is created to simulate the response of strengthened reinforced concrete (RC) slabs under a four-point bending test. The numerical model results in terms of load-deflection behavior, and ultimate loads are verified using previously published experimental data in the literature. The numerical results show a good agreement with the experimental results. The FE model is then employed in a parametric study to inspect the effect of concrete compressive strength on the performance of RC thin slabs strengthened with different FRP types, namely carbon fiber-reinforced polymers (CFRP), polyethylene terephthalate fiber-reinforced polymers (PET-FRP), basalt fiber-reinforced polymers (BFRP) and glass fiber-reinforced polymers (GFRP). The results showed that the highest strength enhancement was obtained by the slab that was strengthened by CFRP sheets. Slabs that were strengthened with other types of FRP sheets showed an almost similar flexural capacity. The effect of concrete compressive strength on the flexural behavior of the strengthened slabs was moderate, with the highest effect being a 15% increase in the ultimate load between two consecutive values of compressive strength, occurring in the CFRP-strengthened slabs. It can thus be concluded that the developed FE model could be used as a platform to predict the behavior of reinforced concrete slabs when strengthened with different types of FRP composites. It can also be concluded that the modulus of elasticity of the composite plays a major role in determining the flexural capacity of the strengthened slabs. [ABSTRACT FROM AUTHOR]

Engineered Cementitious Composite (ECC) exhibits superior tensile ductility, shear capacity, and crack-control ability in comparison to traditional concrete and fiber reinforced concrete. These attributes render ECC a suitable candidate for addressing the brittle punching shear behavior commonly observed in reinforced concrete (RC) flat slabs. To verify the feasibility of using ECC for strengthening the punching shear capacity of concrete slabs, an investigation on the punching behavior of plain ECC slabs was conducted to ascertain their crack patterns, failure mode, strength and energy absorption capacity by means of experiments on twenty-seven 400 mm×400 mm square slabs. The plain ECC slabs were simply supported on a bespoke steel framework with eight supports, centrically loaded with a concentrated load. The fiber volume fraction (FVF) and span-depth ratio (SDR) are the two variables to be examined for their effects on the punching behavior of ECC slabs. Test results revealed that the incorporation of fibers significantly improved the load-bearing capacity, ductility and energy absorption capacity, while it altered the failure mechanism from brittle to ductile. The critical punching shear angles of all tested plain ECC slabs ranged from 40° to 50°. The ECC specimens possessing an FVF of 2 % exhibited markedly superior tensile capabilities compared to those with a 1 % FVF, as evidenced by direct tensile tests. Nevertheless, the ECC slabs with an FVF of 2 % did not demonstrate commensurate improvements in load-bearing capacity relative to their counterparts containing 1 % FVF. The span-depth ratio significantly impacted the failure mode of plain ECC slabs, yielding to punching shear failure at an SDR of 1, and to flexural failure at SDRs of 2 and 3. Moreover, an increase in the SDR value led to a reduction in both the initial cracking load and the ultimate load, concurrently increasing the associated deflection. In addition, a preliminary theoretical analysis was conducted to estimate the bearing capacity of plain ECC slabs. Flexural strength was estimated by yield line theory (YLT) and punching shear resistance was estimated by the model based on theory of plasticity in slab-column systems. The experimental and theoretical investigations could provide insights into the punching and flexural behavior of ECC slabs, laying a groundwork for the design and development of flat systems strengthened with ECC. • The punching and flexural behavior of plain two-way ECC slabs was studied. • The effect of fiber volume fraction on the punching behavior was explored. • The effect of span-depth ratio on the failure mode of ECC slabs was investigated. • The critical punching shear crack angle of plain ECC slabs was determined. [ABSTRACT FROM AUTHOR]

The vibration serviceability assessment of slender and/or lightweight pedestrian systems with high sensitivity to walk-induced effects is rather challenging. In the same way, laminated glass (LG) is used in buildings for structural applications but still represents a not well known and vulnerable material. For pedestrian LG systems, the characterization of dynamic and mechanical parameters may require specific procedures which do not adapt from other constructional typologies. Among others, the mass of pedestrians is generally high compared with LG structural components. Size and restraints in LG may also lead to more pronounced vibration effects. For existing LG systems, moreover, knowledge of residual capacity may be rather difficult. In this paper, an original uncoupled experimental investigation is proposed to numerically address the accuracy and potential of low-cost laboratory body measures for vibration analysis of LG slabs to support (or even replace) field tests or more complex calculation approaches. A total of 40 experimental records are taken into account, in the form of body center of mass (CoM) acceleration time histories for an adult volunteer walking on a rigid concrete slab and equipped with a single high-precision, Wi-Fi triaxial sensor based on micro electromechanical systems (MEMS) technology. Body CoM records are elaborated and used as input for finite element (FE) nonlinear dynamic analysis in the time domain (WL1) of two LG slab configurations (GS1 and GS2) with identical geometry but different boundaries. A third reinforced concrete slab of literature (CS3) is also investigated for further assessment. Numerical parametric results from a total of 120 WL1-based nonlinear dynamic analyses are compared with FE numerical results based on a conventional deterministic approach (WL2) to describe walk-induced effects, as well as towards past field experiments (GS2). The accuracy and potential of the proposed procedure are discussed. [ABSTRACT FROM AUTHOR]

Employing non‐metallic reinforcement made of fiber‐reinforced polymers (FRPs) as textile grids is one promising extension of the utilization range of FRP in concrete construction, and thin planar elements reinforced in this manner have high application potential in bridge or parking garage decks, in façades, or in webs and flanges of hollow core cross‐sections. Existing models for predicting the shear resistance of such elements were derived for solid cross‐sectional dimensions similar to conventional steel‐reinforced structures, and their application to thin slabs is debatable. This paper presents the results of an extensive experimental program on the one‐way shear capacity of slabs without and with carbon FPR textile shear reinforcement. A variation of member height, shear slenderness, and shear reinforcement ratio allowed for analysis of the most relevant influencing factors on shear resistance. Both planar and preformed C‐shaped grids enhance the shear capacity and are suitable as shear reinforcement in thin slabs. The experimental results are the foundation for the extension of shear models to thin slabs with FRP reinforcement and for derivation of new unifying shear models that are applicable to a wider range of reinforcement materials and member dimensions. [ABSTRACT FROM AUTHOR]

The effect of steel fibers on the post-cracking effective moment of inertia of lightly reinforced flexural members was evaluated through four-point bending tests of seven pairs of slab specimens. Variables investigated were steel fiber type (end hooks with either three or four legs) and content (0.26% or 0.38% by volume), and amount of longitudinal reinforcement. Five pairs of specimens were reinforced with minimum reinforcement according to ACI 318-14, while the two other pairs were reinforced with three times the minimum reinforcement. For each reinforcement ratio, one pair of specimens was constructed with regular concrete for comparison purposes. The use of steel fibers led to an increase in effective moment of inertia compared to the companion slabs without fibers, particularly in the slabs with minimum longitudinal reinforcement. The expression proposed by Bischoff (2005) for calculating effective moment of inertia led to reasonable estimates of deflections in the fiber-reinforced concrete slabs when using a tension-stiffening factor βc = 1. For regular concrete slabs, the use of a stiffening factor equal to the ratio between the cracking moment and the applied moment was found to be adequate. [ABSTRACT FROM AUTHOR]

Grout mortars are non-permeable, non-shrink and flowing cement based construction materials. Due to reaching high strength values in a short time, grout mortars are used in construction works. However, behavior of cement mortars under sudden impact loading is complex. Because, loading duration is very short in impact scenarios, effect of strain rates is much higher than static loading. So, dynamic responses and failure modes of the materials are different. In this study, it is aimed to investigate the dynamic behavior of slabs that are produced by cement based grout mortars under impact loading. A drop test setup is developed for this purpose and several measurement devices utilized in the impact experiments. Acceleration, displacement and impact load values are obtained as well as drop durations and drop numbers. After completing the experimental part of the study, artificial neural networks (ANN) analysis which is used to model different physical dynamic processes depending on the experimental variables is performed to predict the impact results. So, ANN analysis is used in the verification of experimental study. Due to the comparison of experimental and analysis results, it is considered that proposed ANN model can be used for the evaluation of the dynamic responses of test specimens. [ABSTRACT FROM AUTHOR]

This paper presents the application of a thick-shell nonlinear finite element analysis procedure to estimate the punching shear resisting performance of reinforced concrete slab-column connections under variable connection shear stress conditions. In the analyses performed, varied connection shear stress conditions stem from slabs being supported by columns with different cross-section aspect ratios, being subjected to different distributions of gravity loading, being constructed with different planar reinforcement ratios in orthogonal directions, as well as the application of unbalanced bending moments. Forty-eight isolated slab-column connection specimens presented in the literature were modelled and analyzed using a thick-shell finite analysis procedure. All numerical results were developed using a predefined set of material models and analysis parameters, a consistent meshing procedure, and are shown to provide meaningful agreement with experimental data without the need for case-specific model calibration or the adoption of specialised failure criteria. The results show that thick-shell modelling methods can be suitable for estimating the punching shear response of slabs subjected to non-uniform shear stress development in connection regions, and can provide similar levels of precision to that obtained for the analysis of idealised slab-column connections typically used for design procedure and model development. • Low-cost shell FEA for punching shear assessment of reinforced concrete flat plates. • Analysis of 45 non-idealised connection specimens representative of real-world construction. • Good agreement between FEA simulations and reported results without model calibration. • Result accuracy comparable to that obtained for more typical idealised connection specimens. [ABSTRACT FROM AUTHOR]

After several decades of research studies, design rules for fiber reinforced concrete (FRC) are now available for several structural elements. Starting from standard tests, it is possible to determine design parameters and constitutive laws to perform simplified sectional verifications and/or numerical analyses. However, one of the main issues still open is represented by the fiber orientation in the real structure that could be different from the one present in standard tests. For this reason, building codes take into account orientation factors to modify the standard material properties. The present paper aims to shed some new lights on the effects of the orientation of steel and macro‐synthetic fibers on the local variability of FRC residual strength properties in slabs made with two concretes: Vibrated (slump of 80 ± 20 mm, V‐FRC) and self‐compacting concrete (slump flow diameter of 700 ± 50 mm, SC‐FRC). In V‐FRC slabs, the orientation of polymer fibers was more influenced by pouring and compaction process compared to steel ones. In SC‐FRC slabs, the flow and wall effects resulted more significant when long steel fibers were used. The post‐cracking performances locally determined in different points of slabs were compared against the ones obtained on standard beams as well. Finally, the global response of these slabs was numerically studied by considering two different support configurations: simply‐supported slabs and slabs on grade. [ABSTRACT FROM AUTHOR]

The purpose of this study is to analyze numerically the effect of explosions on orthotropic slabs which have partial fixity placement and stiffeners in the x direction, namely in the short span direction. The modified blast load dynamic behavior is from Reed's equation with 4th order polynomial on orthotropic plates with x-direction stiffener. The localized blast load centered in the middle of the strain, and the effects of thickness and stiffening on the vertical deflection of the plates are solved numerically using two auxiliary equations in the x and y-directions. It is found that there is vertical deflection with related to time. [ABSTRACT FROM AUTHOR]

Reinforced concrete (RC) slabs are characterized by reduced construction time, versatility, and easier space partitioning. Their structural behavior is not straightforward and, specifically, punching shear strength is a current research topic. In this study an experimental database of 113 RC slabs without shear reinforcement under punching loads was compiled using data available in the literature. A sensitivity analysis of the parameters involved in the punching shear strength assessment was conducted, which highlighted the importance of the flexural reinforcement that are not typically considered for punching shear strength. After a discussion of the current international standards, a new proposed model for punching shear strength and rotation of RC slabs without shear reinforcement was discussed. It was based on a simplified load-rotation curve and new failure criteria that takes into account the flexural reinforcement effects. This experimental database was used to validate the approaches of the current international standards as well as the new proposed model. The latter proved to be a potentially useful design tool. [ABSTRACT FROM AUTHOR]

This paper evaluates the approach adopted by ACI 318-19 for computing deflection of reinforced concrete. Comparison is made with the European approach and Branson's approach used in previous editions of ACI 318. The adopted approach uses a rational expression for the effective moment of inertia, Ie, with a reduced cracking moment that gives greater values of computed deflection for lightly reinforced slabs. The impact of this change on member stiffness and minimum thickness requirements related to immediate and long-term deflection limits for serviceability is evaluated for beams and one-way slabs. Appropriate limits for maximum service load and member span are provided for slabs, and more stringent requirements are needed for minimum thickness of beams. Information about two-way slabs is also provided. [ABSTRACT FROM AUTHOR]

This study investigated the flexural performance of one-way reinforced concrete (RC) slabs strengthened with two distinct strengthening systems: near – surface mounted (NSM) bars and externally bonded (EB) carbon fiber-reinforced polymer (FRP) strips. The NSM bars comprised four types: carbon FRP (CFRP), basalt FRP (BFRP), glass FRP (GFRP), and stainless – steel (SS) bars. The NSM – strengthened slabs showcased substantial enhancements in yield and ultimate load capacity, ranging from 20 % to 55 % and 59–123 %, respectively. In comparison, those strengthened with EB – CFRP strips displayed increases from 46 % to 107 % and 45–177 %, respectively, depending on the axial stiffness ratio of the strengthening system provided. Furthermore, the slabs reinforced with NSM–BFRP bars showed an 11–25 % improvement in their ductility indices. In contrast, the slabs reinforced with EB experienced a decrease in ductility ranging from 38 % to 50 %. This reduction was attributed to the differences in the modes of failure observed in both strengthening systems. The rupture of the NSM–FRP bars and the strain readings associated at the end of testing confirmed that the tensile strength of the NSM–FRP bars was fully exploited whereas the EB–CFRP strips utilized only 29–36 % of their ultimate tensile strain due to debonding. A finite element (FE) model was formulated to anticipate the behavior of the strengthened slabs. A strong correlation between the numerical predictions and the experimental outcomes was observed. The experimental–to–numerical ratios of the ultimate load ranged between 1.0 and 1.08 for the NSM–strengthened slabs and between 0.98 and 1.38 for the EB–strengthened slabs. This validated the FE models' ability to capture the nonlinear performance of the strengthened slabs. • Effectiveness of NSM-FRP varied based on the type of FRP bars. • NSM-FRP bars increased yield and ultimate loads up to 55 and 123 %, respectively. • NSM-strengthened slabs exhibited improved ductility with indices increasing up to 25 %. • EB-strengthened slabs failed due to debonding of the CFRP strips. • NSM-FRP systems are more effective in restoring the ductility of RC slabs. [ABSTRACT FROM AUTHOR]

The use of new reinforcing materials and products in the construction industry requires their thorough assessment for a variety of design situations. One of the significant effects is the shrinkage of the concrete, which in the case of asymmetrically reinforced elements can cause the element to be deformed. The research was focused on slabs asymmetrically reinforced by composite reinforcement (GFRP) and by three reinforcement stages. To eliminate the effect of concrete non-homogeneity, a concrete slab of the same dimensions was made of the same concrete. The results show a significant effect of shrinkage on reinforced slabs. [ABSTRACT FROM AUTHOR]

Modelling the punching of reinforced concrete slabs without transverse reinforcement A mechanically derived model for the punching of reinforced concrete slabs without transverse reinforcement is presented. Starting from Kinnunen and Nylander's classical model a stress field is developed that completely describes the force flow in the slab. Furthermore, a new failure criterion is introduced for the crushing of the compressed conical concrete shell at the transition from the column head to the slab. The inclination of this shell is found from a dimensional analysis. Four model parameters are determined based on a comparison with the results of 54 punching tests. Aiming at the practical implementation approximate formulas for the punching resistance are derived and their application in connection with a linear elastic structural analysis is illustrated. [ABSTRACT FROM AUTHOR]

The slabs of a floating slab track (FST) are usually discontinuously constructed, resulting in a gap between the consecutive slabs. Therefore, wheel/rail impact may occur when a train runs over the gap, resulting in an adverse effect on the train and track system. In this regards, the stiffness enhancement measure (SEM) is usually used at slab ends to enable a smooth stiffness change. The SEM normally includes installing end connections between consecutive slabs and increasing the supporting stiffness of slab ends. For estimating the influence of SEMs on dynamic behaviors of train and FST systems, a detailed and efficient coupled dynamic model of the train–FST system with the SEMs is first developed. Furthermore, the influences of the two SEMs on the system dynamic performance are revealed by using the proposed model. Finally, the optimal parameter combination of the two SEMs is determined, which provide a valuable guiding reference for the design of the FST. [ABSTRACT FROM AUTHOR]

• Propose k ≅ ρ n 0.44 and I cr ≅ 0.36 ρ n 0.81 b d 3 for transformed cracked concrete cross section properties. • Proposed equations are applicable to members of wide range of properties: 0.005 ≤ ρ n ≤ 0.16 • Direct equation for k proves difference between v c for steel– and FRP–reinforced members in ACI 318 and 440 codes can be reconciled. • Modifying ACI-318 equation for v c by E r / E steel 1 / 3 makes it suitable for FRP-reinforced slabs and beams. At service load conditions, deflections and stresses in reinforced concrete (RC) slabs and beams are typically calculated using the properties of the transformed cracked cross section. For more than eighty years, the depth of compression zone factor k in cracked singly-reinforced rectangular RC sections has been calculated using k = 2 ρ n + ρ n 2 - ρ n where ρ is the reinforcement ratio and (n) is the modular ratio. It is shown that in slabs and beams with a wide range of concrete compressive strength f c ′ that are reinforced longitudinally with steel or FRP bars, ρ n ranges from 0.005 to 0.16. Within this range, k can be accurately calculated using k = 0.95 ρ n 0.43 or simply k = ρ n 0.44 . The error between the former equation and the exact equation ranges from –2% to + 3 %. This equation is used to show that the shear strength of concrete v c in the ACI–440.11-22 code for GFRP–reinforced members depends effectively on ρ , f c ′ and d , just like the strength of steel–reinforced members in the ACI–318-19 code equation. It is proposed to apply to the factor E r / E steel 1 / 3 where E r and E steel are the moduli of elasticity of the FRP and the steel bars respectively to the ACI–318 equation to make it suitable also for FRP–reinforced members. This unifies the equation for the two types of reinforcement and provides a better correlation with the experimental results from 233 FRP–reinforced members available in the literature than the current ACI–440.11 code equations. On the other hand, the transformed cracked moment of inertia I cr can be related solely to ρ n and approximated using I cr = 0.36 ρ n 0.81 b d 3 where b and d are the sectional width and effective depth respectively. This equation is used to show that the cracked flexural stiffness is effectively related to the modulus of elasticity and the area of the reinforcing bars raised to the power 0.8, to d 2.2 and to modulus of elasticity of the concrete raised to the power 0.2. [ABSTRACT FROM AUTHOR]

• FE 3D computer models were leveraged for the analysis of composite slab behavior. • Models replicated the deflections and end-slip performances from bending tests. • EC4 assumption of equal longitudinal shear strength on the shear span is observed. • Behavior is influenced by steel thickness, embossments height, and friction value. • The presented approach can facilitate the steel deck design ahead of lab tests. This article introduces a novel modeling and simulation methodology that advances the understanding of steel deck and concrete slab micromechanics for bending and pull-out composite slab tests. Three-dimensional composite models detailed the embossment depth, slope, steel thickness, and tilting angle to overcome previous model simplification assumptions. Newton-Raphson was the simulation method that enabled the consideration of material non-linearities. The validity of each model was contrasted against the results from actual laboratory tests. The model incorporating the non-linearity of materials and a crack inducer was very consistent with the tests. The other two models, which did not account for non-linear behaviors, were partially consistent with test results at complementary bending stages and thus could be combined to reproduce the tests. The robustness of the simulation approach was leveraged to analyze the influence of parametric and boundary conditions in pull-out simulations. Also, micromechanics phenomena that cannot be observed during laboratory tests were investigated. The proposed computing method offers the opportunity to model, predict, and hence optimize the composite slab and steel deck profile design without the need to perform expensive and time-consuming tests on actual specimens. [ABSTRACT FROM AUTHOR]

This paper presents the results of an experimental and analytical study on the flexural behavior of corrosion–damaged reinforced concrete (RC) slabs strengthened with different near–surface mounted fiber–reinforced polymer (NSM–FRP) bars. An accelerated corrosion technique was used to induce corrosion in the steel reinforcing bars of the tested slabs. The investigated parameters comprised the number of NSM–FRP bars (two and four bars), the type of the NSM–FRP reinforcement (basalt B and glass G bars), and the mass loss in the steel rebars due to corrosion (10 and 20%). The yielding and ultimate capacity of the strengthened slabs was not only restored but surpassed those of the virgin control slab. Slabs strengthened with two and four NSM–BFRP bars showed 32–42% increase in their yielding load and 45–50% in their ultimate loads, respectively, as compared to the unstrengthened corroded slab. Similarly, the strengthened slabs showed 5–50% increase in their ductility index as compared to the virgin slab. The strengthened slabs failed due to the yielding of the steel reinforcing bars followed by compression concrete crushing. ACI–440 formulations reasonably predicted the performance of the strengthened slabs with conservative capacities when ACI strain limit of 0.7 ε fu was considered. [ABSTRACT FROM AUTHOR]

This paper presents a novel and efficient nonlinear model developed for analysis of reinforced concrete slabs under monotonic loading. The model accounts for the presence of reinforcing steel and its influence on the micro-cracks formation and propagation; as well as tension stiffening due to steel-concrete residual bond. In the finite element analysis (FEA), the principal barrier encountered in large-scale parametric investigations, with thousands of potential parameter's combinations and modeling executions, it is essential to adopt the fastest and most accurate FEA model. In this regard, the use of shell elements for nonlinear reinforced concrete slab modeling was found to yield superior, far more-efficient solutions that can bring within seconds a higher accuracy than a time consuming, poorly calibrated solid models. Linear-elastic behavior is described with the constant linear-statics moment trajectories, which represent the absence of material and section properties deterioration and nonlinear responses. In contrast, the proposed nonlinear FEA study investigated the material's fourth dimension behavior and model synthesis, calibration, optimization, and efficiency. A summary of the suggested parameters for the proposed time-efficient nonlinear modeling of reinforced concrete slabs under monotonic loading is introduced. It is extremely valuable for large-scale parametric investigations of slabs nonlinearity under monotonic loading up to failure in which the proposed model was compared with many models; all revealing its superior accuracy. [ABSTRACT FROM AUTHOR]

Fiber-reinforced concrete (FRC), particularly steel FRC (SFRC), offers the potential to improve the service level performance of structures by controlling the width of cracks and potentially allowing for a reduction in the amount of traditional reinforcing steel. Full-scale tests of hybrid reinforced concrete (continuous reinforcement with SFRC) one-way slab strips were conducted to investigate the interaction of rebar with SFRC. Parameters varied were slab depth, amount of reinforcement, and location of reinforcement. Readings from strain gages on the rebar were used to investigate the impact of SFRC on the service stresses. Crack width measurements were made at regular intervals and compared to strain readings. In SFRC slabs, service stress limits were reached at larger demands than in RC slabs. When service stress limits were reached in SFRC slabs, crack widths were much smaller than common crack width limits, suggesting design for crack widths may be an appropriate method for addressing serviceability in SFRC slabs. Applying the results of the tests to sample bridges, it was demonstrated that SFRC can be used to either decrease the amount of steel in a bridge deck to satisfy service performance requirements or to increase the slab span without the need for additional reinforcement. [ABSTRACT FROM AUTHOR]

We have considered theoretically the eigenmodes as well as forced electromagnetic and spin waves in ferromagnetic metallic slabs for different boundary conditions for magnetization. We present an algorithm for determination of microwave fields and dynamic magnetization within the slab as well as the transmitted and reflected microwave fields outside the slab. We determine the polarization of the studied waves and show that spatial oscillations of the polarization are formed within the slab. The found oscillations are in particular profound close to the surfaces of the slab in the case of strong surface pinning of spins. [ABSTRACT FROM AUTHOR]

Effective longitudinal segmentation of shashlik calorimeters can be achieved taking advantage of the compactness and reliability of silicon photomultipliers. These photosensors can be embedded in the bulk of the calorimeter and are employed to design very compact shashlik modules that sample electromagnetic and hadronic showers every few radiation lengths. In this paper, we discuss the performance of a calorimeter made up of 12 such modules and able to sample showers every \sim 4X0 . In summer 2016, this prototype has been exposed to electrons, muons, and hadrons at CERN PS (East Area T9 beamline). The performances in terms of energy resolution, linearity, response to minimum ionizing particles, and reconstruction of the shower profile are discussed. [ABSTRACT FROM PUBLISHER]

Carbon-fiber-reinforced polymer (CFRP) grids or textiles for concrete have high application potential in thin planar members such as bridge deck slabs or façade plates. With the high tensile strength of CFRP, shear failure governs design in wider regions, which calls for optimized shear models incorporating all relevant load-transfer mechanisms. The contribution of dowel action to shear resistance is often neglected in shear models derived specifically for FRP reinforcement. As reasons, the low transverse modulus of the anisotropic material and the small cross-sectional areas per reinforcement element and thus small cross-sectional stiffness are mentioned. Yet fundamental research on this mechanism for CFRP grids is amiss. This paper presents a new test setup for characterizing the dowel action of CFRP grids that are pre-strained, similar as in real applications where the reinforcement in the shear crack is stressed in flexural tension. The influence of (pre-) crack width, pre-strain and concrete cover is discussed. By comparison to results from flexural shear-tests it can be shown that, depending on the effective depth, the contribution to shear resistance can be significant. Furthermore, the important role of dowel cracking in the shear-compression failure mechanism could be analyzed using the results of the new dowel test. [ABSTRACT FROM AUTHOR]

Ultra-High Performance Fibre Reinforced Concrete (UHPFRC) is a high-performance cementitious composite that is characterised by superior mechanical properties, high energy absorption capacity and enhanced durability. The mechanical characteristics of UHPFRC and more specifically the enhanced tensile strength and the significant energy absorption and crack resistance make it a very popular material, especially for extreme loading conditions or in cases of thin load bearing elements. UHPFRC has been recently introduced in applications such as bridge decks, and thin slabs and for the strengthening of existing elements. However, the punching shear performance and the effect of the fibres on the punching shear strength of UHPFRC have not been sufficiently studied. Also, there is a lack of provisions for the punching shear design of UHPFRC, which limits the extensive application of UHPFRC in thin elements especially when there are concentrated loads. In this study, extensive experimental work has been conducted on slabs with different geometries and various mixes and valuable results are presented for the flexural and the punching shear capacities of UHPFRC. Also, methodologies for the calculation of the punching shear and the flexural capacities of UHPFRC slabs have been examined and important conclusions have been drawn. • UHPFRC slabs failure mode is highly depended on the mix composition, the thickness of the slabs and the loading conditions. • Increment of steel fibre volume fraction leads to significant enhancement of the punching shear strength of UHPFRC. • Addition of steel bars leads to further enhancement of the UHPFRC punching shear capacity. • Yield line analysis leads to a significant overestimation of the flexural strength capacity of UHPFRC slabs. [ABSTRACT FROM AUTHOR]

One of the main causes of lining damage in stilling basins and at the toe of chute spillways is the global instantaneous uplift forces due to the difference in pressure acting on the upper and the lower surface of protection slabs or rock elements. Spillway stilling basin linings can be built according to two different techniques: using sealed joints or unsealed joints. In the case of sealed joints, the pressure underneath the slab is constant and the uplift force results from the pressure fluctuations acting on the slab. In the case of unsealed joints, the pressure propagation at the lower surface of the slab, being transferred through the joints, should also be considered. The aim of the paper is to study, define, and compare the design criteria in these two cases. In the present study, the pressure field on the slab is evaluated according to a recent method based on the Taylor hypothesis, whereas the pressure propagation under the slab is computed by a new 3D model based on unsteady flow analysis of seepage through porous media. By this approach, it is possible to consider the effect of finite thickness foundation layers, typical in the case of weirs for run-of-river power plants, earth dams, and rock-fill dams. Furthermore, to complete the presented design criteria, the dynamic behavior of anchored slabs is experimentally investigated with reference to the sealed joint case due to a lack of studies in the literature. [ABSTRACT FROM AUTHOR]

Most codes for the design of fiber-reinforced concrete (FRC) structures are based on experience gained over the years with steel fibers. Recent codes include the possibility of applying the same considerations for FRC structures with plastic fiber. However, the consequences of assuming identical design considerations regardless of the type of fiber is scarcely known in terms of the structural behavior of full-scale elements. The main goal of this paper is to assess the influence of the type of fiber on the performance of full-scale concrete slabs, emphasizing the consequences of using a common design approach. For that, a comparative experimental study was conducted to expose differences regarding crack patterns and load-deflection behavior. Then, finite-element simulations were performed using the constitutive equations from a commonly used model code. The results indicate distinct levels of overestimation of the structural behavior measured experimentally, confirming that specific design considerations are required depending on the type of fiber used. Based on the findings, correction factors are proposed for the design of FRC slabs with each fiber. [ABSTRACT FROM AUTHOR]

The Acheulean site of la Noira was fossilized beneath the Fougères fluviatile formation dated by the ESR method at 655 ± 55 ka. Coarse deposits were left at the base after the end of the Cher incision and served as raw material deposits for hominins. The occupation level has yielded bifaces, cores and a flake assemblage in lacustrine millstone. The systematic recording of about 6 500 lithic objects brought to light the reasons underlying the presence of the diverse materials, and elucidated hominin choice of lacustrine millstone for knapping flakes and shaping bifacial pieces. The systematic study of all the materials enabled us to advance hypotheses concerning some of the behaviour identified at the site: sorting of raw materials affected by frost, cursory peripheral knapping of slabs of up to a metre long with hammers weighing several kilogrammes, breaking up of large slabs over 10 cm long and displacement of the fragments. This analysis assesses hominin behaviour and the management and exploitation of raw material deposits at 700 ka. [ABSTRACT FROM AUTHOR]

Analyses of measured pressures using multiple sensors above and below a slab subject to supercritical flow and hydraulic jump are presented. Pressures were measured in a physical model constructed in the Hydraulic Laboratory of the Universidad del Valle in Cali, Colombia. Details such as expansion joints, waterstops, slab thickness, and soil-slab separation were simulated. Inflow was full and partially developed, with Froude numbers ranging from 2.84 to 11.6. The role of the expansion joints and waterstops in the generation of uplift pressure and hydraulic gradient below the slab were identified using pressure fields above and below the slab, in multiple tests. The results of this research are critical for the design of bottom slabs in hydraulic structures, which are required to withstand uplift forces and prevent internal erosion problems. [ABSTRACT FROM AUTHOR]

A steel–concrete composite slab using a cementitious adhesive has been developed to simplify the design of shear connectors between concrete and a steel bottom plate. Fatigue is one of the critical issues for constructed bridge decks, so a moving-wheel fatigue test was performed using the composite slab in a previous study. The test showed the superior fatigue behavior of the proposed composite slab system, while the needs for follow-up research emerged because existing bridge deck slabs frequently suffer from water leakage. The study deals with testing thirteen composite slabs having the cementitious adhesive subjected to water leakage in static and cyclic loadings. Test results show that the fatigue life of the composite slabs in water leakage is significantly lower than that of the slab tested in a dry condition. To further understand the effect of water on reducing the efficacy of the adhesive, supplementary tests are conducted with an emphasis on water-absorption and shear capacity in a wet environment. [ABSTRACT FROM AUTHOR]

Many factors like nonlinear material properties, cracking of concrete, creep and shrinkage of concrete are the parameters which influence the deflections of slab strips. The literature review points out that analytical methods are required to predict the entire load deflection behaviour of restrained slab strips under short term loading. A method is proposed to predict the same for Traditionally Vibrated Concrete (TVC) and Geopolymer Concrete (GPC) slabs. The results are compared with the prediction of Rankine et al and Eyre and Kemp. The results show that the proposed method is able to predict the load deflection behaviour satisfactorily of restrained TVC/GPC slab strips. [ABSTRACT FROM AUTHOR]

Suitable utensils for induction heating appliances are mainly made of good conductor ferromagnetic materials. In this paper, the use of alternative materials is investigated by means of an analytical model of the impedance of the induction system. The results reveal that the electromagnetic properties of graphite are appropriate to design convenient loads for this application. The performance of both bulk graphite and slabs of finite thickness is evaluated and compared with the conventional ferromagnetic materials by means of a figure of merit, consisting of the induction efficiency of the power transference. The comparison shows that the induction efficiency of a graphite slab of appropriate thickness is similar to the efficiency of conventional ferromagnetic materials. Results are experimentally validated by measuring the equivalent resistance of a spiral inductor loaded with graphite slabs of different thicknesses. [ABSTRACT FROM AUTHOR]

During the last several decades, stronger and lighter materials have been developed with the aim of optimizing performance and building costs. These technological advances have given rise to thin flexible flooring systems with natural frequencies that lie within the frequency range of vibrations produced by human activity. Human occupants can cause changes in the dynamic properties of the structure and structural vibrations can cause discomfort to the occupants, who not only perceive the vibrations but also interact dynamically with the structure. This paper presents the results of the characterization of the effect of human-structure interaction (HSI) in three flooring systems commonly used in the Colombian building industry. The methodology consisted in the characterization of the dynamic response of the flooring systems due to different coordinated human activities. Based on the results, the authors recommend that future building codes account for human-structure interaction effects in flooring systems. [ABSTRACT FROM AUTHOR]

• Precast SHCC plates have been prepared, cured, and then used to strengthen RC slabs having cut-outs. • The slabs having cut-outs were strengthened either at the tension side only or at both the tension and compression sides. • The application of SHCC plates at the tension side only for slabs with cut-outs increased the load-carrying capacity accompanied by a loss in ductility. • The application of the SHCC plates at both tension and compression sides of the slabs with cut-outs improved the load-carrying capacity and ductility. Creating a cut-out in an existing Reinforced Concrete (RC) slab became a common practice to allow passing facility services. This cut-out interrupts the loading trajectories resulting in the existence of weak points. Thus, the ultimate capacity of such slab including cut-out decreases with the increase of the size of the opening. In this paper, a new technique based on near-surface mounted has been employed using precast plates made of Strain-Hardening Cementitious Composites (SHCC). These SHCC plates were designed to compensate the cut reinforcement due to cut-out. The used plates had three different widths; 100, 200 and 300 mm, while their thickness was kept constant at 20 mm. One reference slab without cut-out, in addition to, nine damaged slabs with central cut-outs, were prepared and tested under incremental static loading. The tested slabs have the same dimensions; thickness = 140, effective depth = 120 mm, width = 1200 mm and span = 2200 mm. For the cut-out, a rectangular shape with constant width of 200 mm has been used, while the length parallel to the supporting line was varied considering three values; 200, 400, and 600 mm. All slabs were reinforced with a single bottom steel mesh with a longitudinal reinforcement ratio of 0.65%. The slabs having cut-outs were divided into three groups (I, II and III); each one included three different cut-outs. The slabs of group I were tested without strengthening. On the other hand, group II was strengthened at the tension side only, whereas, group III was strengthened at both tension and compression sides. Based on the experimental findings, the load-carrying capacities of group II raised by 15–57% compared to group I; however, this increase was accompanied by a significant decrease in the developed ductility where the displacement-based ductility index could be dropped by 58% for the slab having cut-out length of 600 mm. For group III, the application of SHCC plates at both tension and compression sides enabled the strengthened slabs to restore nearly the lost capacity resulting from providing the cut-out with a good ductility performance. [ABSTRACT FROM AUTHOR]

• Estimating punching shear strength of RC flat slabs using existing methods is associated with high inaccuracy. • New computational intelligence model predicts punching shear strength with superior accuracy. • Novel hybrid Bat-ANN model identified influential design parameter not normally considered by design codes. • Novel hybrid Bat-ANN captures influence of key design parameters. • New model could be integrated in automated design platform for RC structures. While design codes provide guidelines to prevent brittle punching shear failures in flat reinforced concrete (RC) slabs, they are associated with high inaccuracy. This study scrutinizes existing design provisions, highlighting its features and limitations. Sensitivity analysis is then used to identify the influential mechanical and geometric parameters. Subsequently, an artificial neural network coupled with a metaheuristic Bat algorithm (Bat-ANN) is used to develop a hybrid model for estimating punching shear strength. Several statistical metrics revealed that the Bat-ANN model achieved superior predictive accuracy. The novel hybrid model was deployed to assess the influence of key parameters affecting punching shear strength, including the slab effective depth, concrete strength, reinforcement ratio, reinforcement yield strength, and width of the square loaded area. The analysis identified the importance of the flexural reinforcement, which is not typically considered in estimating punching shear strength. Subsequently, using the supervised machine learning method through the EUREQA software, a new regression expression was proposed to estimate the punching shear resistance of flat slabs. This hybrid computational intelligence model could be integrated in future automated design platforms of RC structures. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new mechanical model for reinforced concrete slabs is described. [•] The shear strength of slabs without transverse reinforcement shows a size effect. [•] The principal shear force direction influences the shear strength. [•] Crack faces are able to transfer shear stresses by aggregate interlock. [•] Experimental evidence is confirmed. [Copyright &y& Elsevier]

A number of simplified design methods have been developed to predict composite slab capacities in fire. Most of these extend ambient-temperature large-deflection slab behavior to the elevated-temperature phase by reducing the strengths of fire-exposed concrete and reinforcement while neglecting the effects of thermal expansion and thermal bowing of the slab. Experiments have shown that there are significant differences between the predictions from these methods and the actual behavior and failure modes of ambient- and elevated-temperature concrete slabs in tensile membrane action. Therefore, this paper describes the development of a new analytical method that incorporates both thermal and mechanical effects into the prediction of slab behavior in fire conditions. It uses the variational Rayleigh-Ritz approach to classical large-deflection plate theory. The method is found to produce accurate predictions of deflections and membrane tractions; however, it requires further refinement for accuracy of stresses. The results are compared with numerical modeling using VULCAN, a specialist finite-element (FE) program for structural fire engineering. [ABSTRACT FROM AUTHOR]

In this paper the process of producing steel slabs by continuous casting in the Steel Mill Makstil in Skopje is presented. The technological process of slab's production is described and the assortment of steel slabs in the Steel Mill is given. Also, the most frequent defects of slabs (internal and surfaces) are analysed. Special attention was given to the solidification processes in the continuous casting of slabs. Mathematical modeling of solidification processes during the slab's forming was performed. For this purpose, numerical and analytical methods were applied. The temperature field in the steel solidification area, as well as the liquid phase length were defined. The temperature field was determined by using the finite element method and also by a new analytical method - isothermal method, applying Green's function. In this way, liquid, solid and two-phase area throughout the solidification process were defined. On the basis of direct measurements of the real temperature in the solidification process of the slabs, a comparison of the results, obtained by mathematical modelling and the real ones, was carried out. The comparison points out that the applied numerical and analytical methods display satisfying results in terms of appropriate determination of the solidification process of the steel slabs. The obtained knowledge can be used to optimize the continuous casting process and to improve the quality of the continuous casting steel slabs. [ABSTRACT FROM AUTHOR]

Different nondestructive crack inspection approaches have been previously proposed for a wide range of industrial applications. Among those approaches, field measurement resulting from impressed current crack perturbation has been suggested. In this paper, semi-orthogonal compactly supported spline wavelets are used to efficiently identify the 3D spatial location of embedded cracks in conducting slabs of finite thicknesses. Within the proposed approach a couple of oppositely arranged field sensor pairs are employed on top and bottom of the conducting slab under consideration. Details of the crack detection methodologies and simulations are given in the paper. [ABSTRACT FROM AUTHOR]

Dispersion properties of the dominant modes supported by different 2-D graphene-based nanowaveguides are studied by means of an exact approach based on the transverse-resonance technique and using an equivalent-circuit representation of graphene sheets which also takes into account the spatially dispersive nature of the graphene conductivity: it is quantitatively shown that neglecting spatial-dispersion effects can cause errors in the determination of the modal properties of extremely slow surface waves, also well below the terahertz regime. The modal features of graphene nanowaveguides are thus investigated in detail showing their potential in future nanoelectromagnetic and nanophotonic applications. [ABSTRACT FROM PUBLISHER]