Reinforcement Parameters Research Articles

The mitigating effects of enhanced reinforcer magnitude and quality on treatment degradation.

Differential reinforcement of alternative behavior is a common intervention for problem behavior in persons with neurodevelopmental disorders, but it is susceptible to integrity errors that can degrade treatment effects. Manipulating reinforcement parameters to favor alternative behavior might make it more persistent in the face of integrity errors. We devised an analog of differential reinforcement of alternative behavior to examine if enhanced reinforcer magnitude or quality for the alternative response could protect against treatment degradation. Across 2 experiments, reinforcer magnitude or quality was manipulated to favor the alternative response in 1 condition but kept constant across both alternative and target responses in a second condition. Comparisons of the 2 conditions indicated that higher-magnitude or higher-quality reinforcement for alternative behavior can mitigate against treatment degradation when treatment errors occur and provided support for the utility of considering parameters of reinforcement when developing behavioral interventions for problem behavior.

Mathematical modeling the rigid-plastic yielding behavior of fibrous flatly-reinforced composites of anisotropic materials at 2D stress state

Structural model of multi-directed flatly-reinforced hybrid composites allowing one to determine the yield loci for the composition with account plane stress state in all components is developed. The fiber and matrix materials are homogeneous and anisotropic. Their mechanical behavior is described by associated flow law for rigid-perfectly plastic body with quadratic Mises – Hill yield criterion. As examples, two variants of symmetrical reinforcement for compositions consisting of orthotropic materials are considered under condition of equal reinforcement consumption. The influence of anisotropy characteristics of components and reinforcement parameters on shape and dimensions of the yield loci of the compositions is investigated.

Numerical Deformation Analysis of Reinforced Lightweight Aggregate Concrete Flexural Members.

In the modern construction industry, lightweight aggregate concrete (LWAC) is often used to produce load-bearing structural members. LWAC can be up to 40% lighter by volume than normal strength concrete. However, the lack of adequate numerical models often limits the practical application of innovative building materials such as lightweight concrete in real projects. The present study conducted a comparative numerical deformation analysis of a full-scale bridge deck slab and girder. Using the physical model proposed by the authors and the finite element software ATENA, the deformations of full-scale lightweight and traditional reinforced concrete elements under the short-term effects of permanent and variable loads were compared. Depending on the safety and serviceability limit requirements, it was found that the amount of longitudinal reinforcement in lightweight reinforced concrete elements could be reduced compared with that in standard reinforced concrete elements with the same parameters. The results of the numerical analysis showed that the deformation analysis model proposed by the authors could serve as an alternative tool for the design of lightweight concrete flexural members with the selection of optimum geometric and reinforcement parameters limited by the stiffness condition.

Strengthening of ice with basalt materials

Practical approaches to controlling the strength and deformation properties of ice reinforced with basalt materials (rovings, fibres and nets) and/or modified by dopants of various groups are discussed in this paper. To carry out the entire research on the strength and deformation properties, approximately a thousand of ICMs samples were produced and tested. The three-point bending tests of ice beams and the compression tests of ice cylinders were carried out by authors. It was shown that the introduction of basalt rovings significantly improves the strength and deformation properties of freshwater ice. Ice reinforcement modifies the mechanism of cracks propagation and the overall nature of the specimens' failure. The major morphological and topological factors involved in the manufacture process of high strength ice composite materials were revealed. A combination of basalt rovings reinforcement and chemical modification of the ice matrix with dopants increases the strength properties of the tested ICM specimens by 4-6 times compared to freshwater ice samples. Based on collected experimental data the corresponding recommendations on the choice of reinforcement parameters are given dependent on the functional purpose of the ice composites being implemented.

Strength of Normal and Inclined Sections of Bent Reinforced Concrete Elements with Zone Reinforcement Made of Steel Fiber

On the basis of theoretical and experimental studies, the prerequisites and the method of calculation of bent and compressed-curved reinforced concrete structures with zone reinforcement made of steel fiber, working under static and short-term dynamic loads, are formulated. In the developed method for calculating the strength of normal and inclined sections, a nonlinear deformation model is implemented, which is based on the actual deformation diagrams of materials. The developed calculation method is brought to the program of calculation of reinforced concrete structures with zone reinforcement of steel fiber under short-term dynamic loading, taking into account the inelastic properties of materials. The numerical studies made it possible to determine the influence of various parameters of steel-fiber reinforcement on the strength of reinforced concrete elements. To confirm the main results of the developed calculation method, experimental studies of reinforced concrete beam structures reinforced with conventional reinforcement and a zone steel-fiber layer are planned and carried out. Experimental studies were carried out under static and short-term dynamic loads. As a result of the conducted experiments, data were obtained that characterize the process of destruction, deformation and cracking of steel-reinforced concrete elements under such types of loading. The dependences of changes in the energy intensity of reinforced concrete structures with zone reinforcement made of steel fiber in the compressed and stretched cross-section zones under dynamic loading are obtained. The effectiveness of the use of fiber reinforcement of normal and inclined sections of bent and compressed-curved elements to improve the strength and deformative.

ДЕФОРМИРОВАНИЕ И РАЗРУШЕНИЕ ЖЕЛЕЗОБЕТОННЫХ РАМ С РИГЕЛЯМИ, АРМИРОВАННЫМИ НАКЛОННЫМИ СТЕРЖНЯМИ, ПРИ ОСОБЫХ ВОЗДЕЙСТВИЯХ

The method of experimental and numerical studies of reinforced concrete frame structures with crossbars reinforced with inclined rods under special influences is given. The main objective of these studies was to determine the nature of deformation, cracking and destruction of such structures under special impact caused by the sudden removal of one of the structures and, as a consequence, the redistribution of force flows in them. To increase the survivability and protection of the studied structural system from progressive collapse, with a quantitative and qualitative change in the forces in its elements, it is proposed to install transverse reinforcement from inclined reinforcing rods in two mutually perpendicular directions on the supporting sections of the frame system crossbars. The parameters of such reinforcement and the parameters embedded in the design model of the frame structure under consideration for static loading at the first stage and dynamic loading at the second stage are determined by numerical modeling using the Ansys software package. On this basis, the justification of the adopted design decisions of frame structures for the development of a program for conducting experimental studies of such structures under special influences was carried out.

Reinforcement Effect of Polypropylene Sheet on Soil Strength with Cement

Following thorough soil investigation, the designs for the foundations and other structures are made. The foundations and structures are more reliable and safer when the right soil is used. In this study, cement-coated Polypropylene (PP) sheets were employed to strengthen the soil, enhancing its shear strength and other characteristics. Two (2) soil samples were taken to compare the average outcomes and minimize error. Before using PP sheets for soil reinforcement, various index and strength parameters, such as breaking tensile strength, elastic modulus, and breaking and fusion points, among others, were examined. Properties like liquid and plastic limit, specific gravity, Maximum Dry Density (MDD), and Optimum Moisture Content (OMC) were examined as discussed. Reinforcement of 0%, 0.05%, 0.15%, and 0.25% were applied and tested against shear strength evaluation with the help of a direct shear test. An increase in strength is observed in soil samples 1 and 2, i.e., 1.27, 2.25, 2.27 and 1.28, 1.42, 1.65, and 1.79 in kg/cm2, respectively. Similarly, unconfined compression strength was observed to increase from 0.0692 MPA to 0.0942 MPA, which is 11.68% and 35.94% increment in soil samples 1 and 2 at 0% and 0.05% reinforcement, respectively.

Experimental investigation of mechanical properties of Al7075-Al2O3-B4C composite via stir route

Aluminium metal matrix composites have large structural applications in automobile, aeronautical, sports and defence industries. Hybrid composites having two or more two reinforcements can be used for advanced industrial applications. The properties of the composites depend on the selection of an appropriate combination of matrix, reinforcement and processing parameters. Therefore present work aims to develop hybrid aluminium composites with varying weight percentages of particulate reinforcements and investigate their mechanical and tribological properties. In this study, AA7075 is used as the matrix material and the reinforcements reinforced are alumina, boron carbide and carbon. The wear, tensile and flexural behavior of the composites are also analyzed using the scanning electron microscope.

Level formation and disclosure of normal cracks in reinforced concrete elements and structures

The article is devoted to the study of the main regularities of the normal cracks level formation in reinforced concrete elements and structures. A critical analysis of the latest publications related to the theme of these studies has been carried out. The main characteristics of prototypes, the conditions for their manufacture and storage are given. Based on the experimental studies results, it has been established that in the real design of bending reinforced concrete elements, when calculating their crack resistance, one can restrict oneself to only two levels of normal cracking. A statistical comparison of the calculation results using the author’s and other methods with experimental data confirmed the effectiveness of those calculation methods in which the crack formation step is directly related to the basic laws and parameters of reinforcement to concrete adhesion.

Effect of reinforcement parameters on the impact resistance of cementitious composites for vehicle restraint systems

The presented study investigates the dynamic resistance of cement-based large-format elements with various types of reinforcement and retrofitting. Both inner and outer reinforcement has been assessed. The effect of matrix type (low, high, and ultra-high-strength), amount of steel fibres, and ribbed reinforcing steel on impact toughness has been evaluated. The influence of an additional polymer-based layer to increase impact resistance level has also been investigated. The effectiveness of each reinforcing method has been compared. An large-scale impact hammer device KYV-I-2020 (up to 1100 J) has been used to determine the impact toughness. The results show that ribbed reinforcing steel increases the impact toughness more effectively than the fibre reinforcement, steel mesh and additional polymer layer. However, fibers significantly reduce fragmentation, especially at a higher concentration of 2.5 vol%, contributing to the overall higher impact resistance of the elements and their safety in practical use. The test results also show a significant effect of the matrix type, with the most increased impact toughness achieved when using a high strength matrix. The addition of an antifragmentation polymer layer then provides a further increase in impact toughness. The results also indicate that similar resistance capacity can be achieved using different reinforcement combinations, which is crucial for designing the material composition with the optimal performance/cost ratio. The presented research is a part of the development process of the restraint systems for stopping trucks. The data obtained has been used to create the elements with suitable composition; their effectiveness has been successfully verified by numerical simulations and real tests.

Taguchi Grey Relational Optimization of the Multi-mechanical Characteristics of Kaolin Reinforced Hydroxyapatite: Effect of Fabrication Parameters

Comparative study of kaolin reinforced hydroxyapatite (KHAp) and pure HAp using different production parameters has been done through traditional experimentation. However, the quantitative effect, optimization of kaolin reinforcement and fabrication parameters have not been investigated. Hence, this study examines the effect of kaolin reinforcement, compaction pressure and sintering temperature on the experimental mechanical properties of HAp. Taguchi design assisted by grey relational analysis was employed with L36 (2**2 3**1) orthogonal array. The Minitab 16 software was used to analyze the Taguchi design. The result showed a disparity in kaolin reinforcement as the optimum condition for individual mechanical properties, but the grey relational analysis showed better mechanical properties with kaolin reinforcement, 500 Pa compaction pressure and 1100 oC sintering temperature. The obtained result further revealed kaolin reinforcement as a strong and promising reinforcing material for high strength clinical application, having a contribution of 93.16% on compressive strength of HAp. Therefore, future studies can be conducted in the use of different wt% of kaolin on the multi-response mechanical characteristics of HAp.

Deformation Characteristic of a Supported Deep Excavation System: A Case Study in Red Sandstone Stratum

A complete case record of a deep foundation pit with pile-anchor retaining structure excavated in red sandstone stratum is presented in this study. The horizontal displacement of pile top, the horizontal displacement at various depths, the axial force of anchor cable, and ground settlement during construction are measured. A three-dimensional numerical model is established to analyze the additional stress and deformation induced by the excavation and the accuracy of the FEM model is verified by comparing with field measured results. Both the measured and numerical simulation results show that the deformation of the pile-anchor supported deep excavation is significantly affected by the spatial effect. The results show that the deformation in the middle of the foundation pit is greater than the pit angle and that the deformation of the long side is greater than that of the short side and gradually decreases from the middle to the pit angle. The deformation and stress in the middle of the long side of the foundation pit are the largest, which is the most unfavorable part. With the increase of vertical excavation depth, the spatial effects tend to increase, and the influence scope of spatial effects is about five times the vertical excavation depth in the red sandstone stratum. The ground settlement outside the pit is mainly distributed in a groove shape, and the maximum settlement occurs about 8.5 m away from the pit edge. Finally, parametric studies of reinforcement parameters indicated that 1.5–2.0 times the initial elastic modulus and cohesive force of soil should be used for reinforcement. It is recommended that the ranges for pile diameter, pile spacing, anchor cable prestressing and inclination angle should be selected as 0.8–1.2 m, 1.4–2.0 m, 100–150 kN, and 10°–20°, respectively.

On the large-amplitude vibration of rotating pre-twisted graphene nanocomposite blades in a thermal environment

The large-amplitude free vibration behaviors of rotating pre-twisted functionally graded (FG) nanocomposite multilayered blade reinforced with graphene platelets (GPLs) in a thermal environment is comprehensively investigated in the paper. It is assumed that the GPLs volume fraction varies gradually from layer to layer across the blade thickness direction but remains constant in each individual GPLs-reinforced composite (GPLRC) layer. The modified Halpin-Tsai micromechanical model is exploited to obtain the effective Young’s modulus of each GPLRC layer while Poisson’s ratio, mass density, and thermal expansion coefficient are determined via Voigt’s rule. The nonlinear dynamic model of pre-twisted GPLRC blades at moderate rotational speed in a thermal environment is derived based on the first-order shear deformation theory (FSDT) combined with the improved version of the Novozhilov nonlinear shell theory. The nonlinear vibration characteristics of FG GPLRC blades are obtained by applying the element-free improved moving least-square Ritz (IMLS-Ritz) method in conjunction with a direct iterative scheme. Validation of obtained results is performed in detail and show effectiveness of used numerical approach and fast convergence of obtained results to exact values. The impacts of rotating speed, pre-twisted angle, presetting angle, and aspect ratio on nonlinear to linear frequency ratio of GPLRC blades are studied with emphasis on temperature rise and nano reinforcement parameters. Finally, new insights into dynamics of nanocomposite rotating blades with conclusions are presented in detail.

Analysis of the influence of design parameters on the agro-ecological qualities of tractor tires

Experimental studies of the impact of agricultural mobile machinery movers on the soil are seasonal in nature and require complex experimental equipment. The complexity of the physical processes occurring in the elastic wheel-ground system requires the introduction of many assumptions and limitations that reduce the accuracy of the results, according to the design of simulation models performed in the software environment. The aim of the research was to study the influence of the design parameters of the tire on the efficiency of the normal deflection along the contact spot zone X. Studies have shown that 65% to 77% of the normal deflection of the tire is used when passing the contact spot. The reinforcement parameters of the tire frame have the greatest impact on the efficiency of the normal deflection along the contact spot zone. With an increase in the number of layers of the frame cord from 2 to 8, the coefficient of usability of the normal deviation for the stroke of the contact spot decreases from 0.761 to 0.689, with an increase in the angle of inclination of the frame cords - decreases from 0.755 to 0.693.

Experiment and Numerical Simulation on Grouting Reinforcement Parameters of Ultra-Shallow Buried Double-Arch Tunnel

For an ultra-shallow buried double-arch tunnel with a large cross-section, the arching effect is difficult to form in surrounding rock, and grouting method is often adopted to reinforce the surrounding rock. Hence, examining the grouting reinforcement parameters is of great significance for potential failure and collapse prevention. The land part of Haicang undersea tunnel was selected as a case study; laboratory experiments, theoretical analysis, and numerical simulation were performed to determine the grouting solid strength and grouting reinforcement parameters. The effects of different water–cement ratios on slurry fluidity, setting time, bleeding rate, and sample strength were studied by laboratory experiments. A method was proposed to determine the shear strength parameters of grouted surrounding rock through the grout water–cement ratio and the unconfined compressive strength of the rock mass. Numerical simulations were performed for grouting reinforcement layer thickness and the water–cement ratios. The deformation and stability law of tunnel surrounding rock and its influence on surrounding underground pipelines were obtained considering the spatial effect of tunnel excavation and grouting reinforcement. The reasonable selection range of grouting reinforcement parameters was proposed. The initial setting time and bleeding rate of cement slurry increased with the increasing water–cement ratio, while the viscosity of cement slurry and sample strength decreased with the increasing water–cement ratio. The shear strength parameters of grouted surrounding rock were determined by the water–cement ratio of grout and unconfined compressive strength of rock mass before grouting. When the thickness of grouting reinforcement layer h = 1.5 m and the water–cement ratio of grout was suggested η = 0.85, the surface settlement, the deformation of the vault, and the deformation of the nearby pipeline all met the design. Moreover, the construction requirements were more economical. Research results can provide a reference for the selection of grouting reinforcement parameters for similar projects.

Investigation of mechanical properties and crack resistance parameters of steel reinforcements of reinforced concrete structures of long-term special term

It is known that the fatigue process begins with the plastic deformation of the surface layers of the metal fittings. Moreover, the displacement of dislocations under conditions of re-alternating loads is observed at loads below the elastic limit of the metal. The rate of local plastic deformation during cyclic deformation is several orders of magnitude higher than the rate of deformation under static loading. Dislocation slip begins in grains with a favorable orientation near stress concentrators. As the number of cycles in the surface layers increases, the density of dislocations and the number of vacancies increases. When the base number of NR cycles is reached, a surface reinforced layer of metal with a large number of germinal cracks is formed, the size of which does not reach a critical value. Increasing the number of cycles cannot cause further development of fracture in such a layer. Only when the stresses exceed the endurance limit of the crack reach a critical length, after which the process of their discharge into the main crack begins with the spread of the latter. The results of experimental studies indicate a strong effect of diffusion hydrogen on static and cyclic parameters of crack resistance. It was found that with increasing flooding, especially when the hydrogen content exceeds 5 cm3/100g, both static strength and long-term strength (fatigue) decrease sharply. Moreover, for these areas of hydrogen solution in reinforcing steel is characterized by a viscous nature of fracture, while for heavily flooded reinforcement (from 5 to 12 cm3/100g is characterized by brittle fracture by the mechanism of microfission in the hardened (martensite or troostite structure). allowed to determine the optimal hydrogen content in reinforcing steel (3…5 cm3 /100g), the excess of which will reduce the crack resistance of reinforcement during long-term operation, especially in corrosive environments. The results of the research confirm the above data. bainite structure y sharply reduces the crack resistance of reinforcing steel, which makes it impossible to use in the manufacture of reinforcement involved in reinforced concrete structures designed for long-term operation (more than 50…60 years). Thus, the obtained diagram can be recommended to designers of reinforced concrete structures for hydraulic purposes, as it greatly facilitates the reasonable choice of reinforcement in the development of reinforced concrete structures for responsible and long-term use.

Optimum planar reinforcement parameters for enhancing the load carrying capacity of strip foundations on reinforced sandy soils

Optimum planar reinforcement parameters for enhancing the load carrying capacity of strip foundations on reinforced sandy soils

Stochastic seismic analysis of geosynthetic-reinforced soil slopes using the probability density evolution method

This paper presents a stochastic seismic analysis of geosynthetic-reinforced soil slopes (GRSS) using the probability density evolution method (PDEM). The combination of the uncertainties of seismic ground motions (SGM), soil properties and reinforcement parameters was considered. The stochastic SGM was generated from a random function based on the spectral representation method. The present method is proved to be more precise than the pseudo-static method and pseudo-dynamic method due to the consideration of the uncertainty of frequency spectrum of seismic excitations, and more efficient than the Monte Carlo simulation method for reducing the number of samples by 39 times. Without involving the stochastic earthquake, the result of the estimated performance would incur large errors since it greatly depends on the selected earthquakes, which may be one of the major reasons for GRSS failure. The slope displacement and the reinforcement strain occur at a relatively narrow region at the beginning, then increase and fluctuate intensively with large uncertainty, and finally become steady in the earthquake decay phase. The reinforcement length has a more substantial influence on the failure probability of the reinforcement than other parameters in the studied ranges. The reinforcement strain increases but the slope displacement decreases with the reinforcement length because of the variation of failure mechanisms.

Multivariate façade strengthening systems of textured layers in large slab panel buildings

This article presents the solutions of bonded anchors used to strengthen façade textured layers in the walls of three-layer large slab panel buildings in Poland. Large slab panel building systems that are found in Poland have been characterized. The use of new bonded anchors is preceded by diagnostics of the walls of three-layer large slab panel buildings. The author presents two-stage diagnostics: non-destructive methods, measurement of reinforcement parameters and its condition using a Profometer type device, and destructive methods by performing an opencast with a drilling rig. A review of previously used bonded anchorages in Poland was carried out. Proposals for the use of anchor groups in various configurations with different angles of inclination of the diagonal anchors were also presented in order to achieve the most durable effect possible.

Finite element analysis and design method of geosynthetic-reinforced soil foundation subjected to normal fault movement

This paper presents a series of finite element analyses to investigate the performance and reinforcing mechanism of geosynthetic-reinforced soil (GRS) foundations subjected to normal fault movement. Numerical and experimental results of unreinforced and reinforced foundations were first compared for model validation. Parametric studies were then conducted to evaluate the influence of soil and reinforcement parameters on the performance of reinforced foundations. The total height of the baseline reinforced foundation was 3 m in the prototype scale, and this foundation was subjected to fault movement of up to 1 m (S/H = 33%). The variables considered in the parametric studies included reinforcement length, stiffness, ultimate tensile strength, vertical spacing, foundation height, and soil–reinforcement interface property. The numerical results revealed that FE analysis satisfactorily predicted the deformation behavior of unreinforced and reinforced foundations subjected to normal fault movement. Two main reinforcing mechanisms identified in this study were tensioned membrane and shear rupture interception effects. Based on the numerical results, regression equations for predicting the maximum angular distortion and the mobilized reinforcement tensile strain induced by normal fault movement were established. Design methods were also developed for determining the reinforcement length (against significant pullout) and failure strain (against breakage).