Reinforcement Elements Research Articles

Impact of steel properties on the susceptibility to corrosion of weld mesh and mesh straps

Reinforcement and surface support are part of an integrated system that transfers and shares load until the excavation surface is stabilized or until the ground support system fails. Steel mesh is the most popular primary surface support element in underground hard rock mines in Canada. Mesh straps are a secondary surface support that provide additional containment as they distribute the load between and across the reinforcement elements. This investigation addresses the role of steel properties, and in particular steel chemistry, in the long-term performance of mesh and mesh straps when exposed to an aggressive corrosive environment. It reports on comparative accelerated corrosion studies to compare the resistance to corrosion of different surface support elements. This has significant implications on the choice of surface support and the anticipated rehabilitation requirements.

Cryogels Composites: Recent Improvement in Bone Tissue Engineering.

Autogenous bone grafts have long been considered the optimal choice for bone reconstruction due to their excellent biocompatibility and osteogenic properties. However, their limited availability and associated donor site morbidity have led to exploration of alternative bone substitutes. Cryogels, with their interconnected porosity, shape recovery, and enhanced mass transport capabilities, have emerged as a promising polymer-based solution. By incorporating bioactive glasses and nanofillers, cryogel composites offer bioactivity, cost-efficiency, and easy cell integration. This approach not only enhances bone regeneration but also underscores the broader role of nanotechnology in regenerative medicine. This mini-review discusses the advancement of organic-inorganic composites, focusing on biopolymeric cryogels and inorganic elements for reinforcement. We highlight how cryogels can be integrated into minimally invasive procedures, reducing patient distress and complications, and advanced 3D-printing techniques that enable further customization of these materials to mimic bone tissue architecture, offering potential for patient-specific treatments.

Analytical model for RC coupling beam considering axial restraint

A novel three-dimensional distributed plasticity model element is formulated and implemented into an open-source computational platform (OpenSees) to enhance nonlinear modeling approaches for lateral force resisting systems utilizing diagonally reinforced concrete coupling beams. The model incorporates a fiber-based concrete cross-section along with truss elements to represent the diagonal reinforcement and contact elements to model reinforcing bar slip at the beam-wall interface. The model is validated using test results from five different experiments that include variations in cross-section geometries, reinforcement configurations, and boundary conditions. Notably, two test specimens shared identical attributes except for their cross-sectional shapes (with and without a slab), whereas another pair were identical except for the degree of axial restraint provided. The final specimen utilized both longitudinal and diagonal reinforcement along the length of the beam. The model accurately predicted overall shear versus chord rotation responses with errors < 5 % and axial growth responses with errors < 30 %. The proposed model provides enhanced modeling options for nonlinear analysis by enabling sensitivity studies to address the potential impacts of coupling beam axial restraint on coupling beam and coupled wall behavior.

Flexure Performance of Textile-Reinforced Cementitious Composites with Novel Inclined Reinforcements.

Textile-reinforced cementitious composites have great potential to offer novel design opportunities for thin-section structures thanks to their superior material capabilities. In this work, new cementitious composites with novel reinforcement configurations are developed, which have superior mechanical properties. The cementitious composites contain inclined through-the-thickness reinforcements, and their enhanced performance on thin-section material hardening under flexural loading is demonstrated. Furthermore, a new practical FE modeling approach is proposed that involves the combined use of multiple cohesive regions and 1D reinforcement elements that pass through these regions with a bilinear material law. This approach provides a new computationally efficient modelling framework whereby reinforcement pull-out during hardening is readily captured without resorting to computationally demanding interface laws between the reinforcement and the cementititous matrix. The model can model enhanced hardening of new configurations and provides comparable results with the experimental findings. The model can be used in the modelling and design of novel cementitious composites with engineered reinforcement configurations. Overall, this study aims to open up new avenues for the smart material design of cementitious composites with novel structural reinforcements.

DEVELOPMENT OF METHODOLOGY AND STUDY OF THE INFLUENCE OF TECHNICAL, ORGANIZATIONAL AND TECHNOLOGICAL FACTORS ON THE DURATION OF THE PROCESS OF LIQUIDATION AND LOCALIZATION OF THE DEVELOPMENT OF DESTRUCTIONS

Analysis of the influence of technical, organizational and technological factors on the duration of the process of liquidation and localization of the development of destruction is an important stage of research into the process of liquidation of the consequences of accidental destruction. In order to compare options for liquidation and localization of the development of destruction of an emergency building, three options for reinforcement systems were analyzed: metal typical, wooden individual and combined. The work uses the method of analysis of hierarchies - a mathematical tool of a systematic approach to complex decision-making problems. The method does not impose the "correct" option, but allows you to interactively find an alternative (rational reinforcement option) that best matches the requirements for solving optimization tasks. To reduce the subjectivity of making a justified optimization decision in the conditions of complex multi-criteria optimization problems, a solution to the local problem of finding the optimal alternative according to the duration criterion, or a group of alternatives, taking into account the ratio of advantages based on the vector criterion, is proposed. To indicate the influence of advantages in quantitative expression, a pairwise comparison scale was used, which consists in a qualitative and quantitative assessment of relative advantage: equal in importance - 1; weak advantage – 2; average degree of preference ‒ 3; preference above the average degree ‒ 4; moderately stronger advantage ‒ 5; strong advantage ‒ 6; much stronger advantage ‒ 7; the most significant advantage is 8; absolute advantage ‒ 9. Initial data for choosing a temporary reinforcement option were obtained by comparing the estimated duration of dismantling and restoration works and optimizing the sequence of their execution for three options using wooden individual, metal typical and combined temporary reinforcement systems. It was established that it is impossible to ensure complete unification of reinforcement elements using only typical elements, therefore it is effective to use combined reinforcement systems using typical metal and individual wooden elements.

The corrosion behavior of graphene reinforced titanium matrix composites in 3.5 wt% NaCl solution

Graphene is widely preferred as a reinforcement element to enhance mostly mechanical properties of titanium matrix composites due to its unique properties. However, the number of detailed studies is quite limited in the literature on the corrosion properties of graphene reinforced titanium composites. Therefore, the effects of graphene amount on the corrosion properties of titanium composites were evaluated in this study. Pure titanium and graphene‑titanium composites for various amount of graphene (0.15, 0.30 and 0.45 wt%) were produced by powder metallurgy. The electrochemical impedance spectroscopy was used to analyze the corrosion properties of the samples in 3.5 wt% NaCl solution. From the results, TiGr15 sample was observed as maximum corrosion resistance with 6.6939 × 10+5 (Ω·cm2). The cyclic potentiodynamic polarization method results showed that TiGr15 sample (0.0007 mA/cm2) has the lowest corrosion flow rate. Moreover, the SEM-EDX images of the corroded samples showed that the highest cohesion of constituent particles and the least amount of corrosion, particle separation were observed at Ti-0.15 wt% graphene.

Assessment of the utilization of cement-treated geotextile as a reinforcement element for highway base layer under cyclic loading

This study conducted large-scale cyclic loading experiments on the base layer overlying a weak subgrade soil. Geotextile and cement-treated geotextile were utilized to reinforce the base material and to separate the interface of soils between the base layer and the subgrade. The results obtained from the repeated loading tests using geotextile and cement-treated geotextile were analyzed and evaluated in terms of some benchmark indicators such as total deformation, permanent deformation, elastic deformation, percentage of elastic deformation, traffic benefit ratio (TBR), elastic modulus (MR), improvement factor (If), and rut depth reduction ratio (RDR). Based on the experimental results, the use of cement-treated geotextile as a base layer reinforcement element or as an interfacial separation element demonstrated better performance compared to the use of geotextile. Utilization of a cement-treated geotextile as both reinforcement and separation element resulted in an RDR value of 49.26 % after 5000 cycles. Additionally, using a cement-treated geotextile for both reinforcement and separation increased the TBR value to 14.62 at 27 mm deformation, decreased the permanent deformation value from 53.67 mm to 27.23 mm, and approached approximately 2 improvement factor values, compared to using the geotextile solely for separation.

Investigating the potential of powder metallurgy for fabricating graphene nanoplatelets reinforced copper nanocomposites

Copper (Cu) is highly sought for its excellent electrical and thermal conductivity. However, its limited mechanical strength hinders its wider application in demanding fields. This work explores the potential of graphene nanoplatelets (GNPs) as a strengthening agent for Cu. Cu-GNP composites with varying GNP content (0.1–1.5 wt%) were fabricated using a combined ball milling and powder metallurgy approach. The microstructure and mechanical properties of the composites were comprehensively analyzed using field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Raman spectroscopy. Compared to pure Cu, the Cu-GNP composites showcased significantly improved mechanical performance. Notably, the Cu-1.0 wt% GNP composite exhibited a remarkable ∼27% and ∼53% enhancement in compressive strength and micro-hardness, respectively. This improvement is attributed to the effective load transfer between Cu and well-dispersed GNPs, which act as reinforcement elements and inhibit dislocation movement. These findings demonstrate the promising potential of Cu-GNP composites for applications requiring high strength.

Numerical Investigation of the Effect of Deltoid Radius on Tensile Load in T-joints

In this study, T-shaped joints were designed from composites with different deltoid radius. For this purpose, carbon fiber woven fabrics were preferred as reinforcement elements. Then, tensile analyzes were performed on these composite T-joints. The effect of the deltoid radius on the maximum tensile load and damage behavior of the structure was examined. As a result of the analyses, fiber tensile-compression damage images occurring in the structure for each deltoid radius were obtained along with the load-displacement graph. The Hashin damage criterion was preferred for damage onset. Material Property Degradation (MPDG) method was used for damage progression in progressive damage analysis. By increasing the deltoid radius from 6 mm to 12 mm, the maximum contact load increased by approximately 10%, and by increasing it to 18 mm, the maximum contact load increased by approximately 20.11%. Fiber compression damage, spread over a wide area on the lower surface of the flange where it does not come into contact with the web, was determined to be the dominant damage type, and it was determined that this damage decreased with the increase of the deltoid radius. it was observed that as the deltoid radius increases, the T-jointed composite structure exhibits more rigid material behavior.

Continuity breakageof cableinorthotropic stay rope of rectangular cross-section

Purpose. Construction of an algorithm for determining a stress-strain state of a multi-layer stay rope of a rectangular cross-section with a broken reinforcing fiber. Methods. Analytical solution of an interaction model of parallel fibers connected by elastic material of a stay rope of rectangular cross-section in the event of reinforcing element breakage using methods of mechanics of layered composite materials with soft and hard layers. Findings. An analytical algorithm for determining a stress-strain state of a composite stay rope of rectangular cross-section with a damaged reinforcing fiber is constructed.An analytical method for determining a stress-strain state of a rope with a comprehensive consideration of structure, mechanical properties of components, layout of reinforcing fibers in a cross-section, in a presence of a broken fiber, is developed in a closed form.It is established that load unevenness on fibers is practically independent of the ratio of an amount of fibers and layers in a rope and their total amount, and the ratio of fiber placement spacing in layers and spacing of layers in case of fiber breakage in a stay rope cross-section. Scientific novelty. It is established that load unevenness on fiber does not depend on a ratio of an amount of fibers and amount of layers in a stay rope. Practical significance. The developed algorithm makes it possible to determine the share of tractive capacity loss of a stay rope of rectangular cross-section due to breakage of a reinforcing element. The known value of lost strength makes it possible to establish acceptable conditions for use of a rope of rectangular cross-section. It is advisable to give a rope a shape with less resistance to air pressure by reducing the amount of layers compared to the amount of fibers in layers. Damage to a corner element of cable reinforcement is more dangerous, it leads to a load increase of almost 30 % in the most loaded fiber, while the specified parameter is less than 20 % in case of a breakage of the central fiber.

Experimental evaluation of mechanical characteristics of concrete composites reinforced with jute fibers using bricks waste as alternate material for aggregates

In order to achieve high strength in concrete composites, various fiber reinforcements in plain concrete composites (PCC) are used. Steel is widely used for this purpose but the main issue in using steel as a reinforcement member is rusting, which results into structure deterioration. So, the alternative is to use a durable, environment friendly, and cost-effective natural fiber. Jute Fiber is used in this study for the reinforcement of plain concrete composites while, the plain concrete composites were made with cement, sand, and bricks waste. The comparative study of using bricks waste as an alternative material to crush bricks is also presented in this research study. Bricks waste and its disposal is becoming an environmental challenge. This study proposes jute fibers as a reinforcement element and uses bricks waste as an alternative material to crushed stone. M20 grade concrete with various volumetric percentages (0.05%, 0.10%, 0.25%, 0.50%, and 1.00%) of 10 mm long jute fibers are produced. An increase of 39% and 37% in compressive strength and split tensile strength, respectively, was observed after the addition of jute fibers. Therefore, the use of jute fibers and bricks waste to replace crushed stone is an effective way to mitigate environmental pollution and sustainability issues.

Dowel bars – reinforcing elements of cement concrete pavements

Our aim is to analyze the function of reinforcement elements (dowel bars) in cement concrete pavement to highlight the influence of these elements on the service life of the pavement as a whole and to find possible alternatives to existing products that are freely available on the Czech market. That is, how these elements in the form of dowel bars should work properly so that the function meets the design assumptions of a rigid pavement. We describe the procedure for inserting dowel bars during paving, which is directly related to the possibilities of using different dowel bars. Finally, we summarize the possibilities of using alternative materials, shapes, or sizes of dowel bars and the possibilities of their use in the Czech Republic.

RESULTS OF EXPERIMENTAL TRAY STUDIES OF THE SOIL FOUNDATION BASE REINFORCED WITH MICROPILES

Purpose. Obtaining a change in the deformed state of models of unreinforced and reinforced micropile soil base to determine the influence of the reinforcement element. Methodology. The method of research in a flat tray was used, which makes it possible to solve a certain range of tasks related to the interaction of foundations with the soil base. The conditions for conducting experimental research and the features of creating models of unreinforced and micropile reinforced soil bases are given. The conditions for creating clay paste, laying it in a flat tray, preparing the model for loading, and taking measurements are given in detail. To assess the adequacy of experimental tray studies, modeling conditions were calculated based on the parameters of a real civil structure, its foundation and soil base. Findings. During the experimental studies of the soil foundation and its interaction with the base in a flat tray, two series of experiments were conducted, three experiments in each series. In series Nos. 1-3, an unreinforced base was studied, in series Nos. 4-6, a base reinforced with a single micropile. Vertical displacements were averaged, which were measured by three dial indicators installed in the middle and on both sides of the die that modeled the foundation. On the basis of the results obtained during the experimental studies, diagrams were plotted in σ – s coordinates (stress – settlement). Originality. The originality of the work consists of obtaining a change in the deformed state of the models of unreinforced and micropile reinforced soil base and determining the influence of the reinforcement element (the maximum vertical displacement of 14.7 mm in the model reinforced with micropile in contrast to 17.5 mm in the unreinforced one, i.e., the reduction of this component of the deformed state by 1.19 times). Practical value. The practical value of the conducted research lies in the proof of the positive impact of micropiles based on the results of experimental tray studies. Based on the obtained results, it is reasonable to apply micropiles created with the help of drilling-mixing technology to successfully reduce the vertical displacements of the foundations of civil structures on weak soil bases.

Mechanical performance and application of retaining structures doubling as permanent structures in deep excavations

This study examines the effectiveness of the prefabricated pile-wall composite retaining structure (PW-CRS), which is a cutting-edge construction technique that combines prefabricated retaining piles with internal structural walls and is being increasingly utilized in excavation engineering projects. To comprehensively assess its performance, the research adopts a simulated loading approach, using equivalent concentrated loads to mimic the actual conditions faced by the PW-CRS. The experimental analysis highlights inclined tension failure as the predominant form of structural failure, accompanied by extensive cracking in both the pile and wall components. Additionally, the study points to slip failure of the laminated surfaces as a significant factor influencing the load-bearing capacity of the structure. The strain assessments on both concrete and reinforcement elements further enrich the findings. This investigation enhances the understanding of the structural dynamics of the prefabricated PW-CRS and offers valuable insights for its effective application in excavation engineering projects.

Mitigation of tunnel support design risks for hydropower projects within high tectonic stress regimes – an empirical analysis

Abstract The study for the design of tunnels in similar geological settings, providing insights into potential challenges that may arise during excavation and offering strategies for mitigating risks in District Kalam on the Ushu River, Khyber Pakhtunkhwa, Pakistan. The methodology involved geological mapping, rock sampling, discontinuity surveys, and laboratory testing for empirical analysis of tunnel parameters at the Weir House, Powerhouse, and tunnel alignment locations. Empirical analysis of tunnel parameters using three rock classification systems, rock mass rating (RMR), rock quality tunneling index, and rock mass index (RMi). Based on the classification, the rock quality was found to be fair, indicating favorable rock properties. The Q-system rated the rock as poor to fair, suggesting low discontinuity intensity, medium rock strength, or medium deformation modulus. According to the RMi, rock was rated as medium to strong, indicating low discontinuity intensity, high rock strength, or low deformability. The support design for the tunnel is based on empirical analysis, it recommends support design for the tunnel reinforcement elements such as rock bolts, wire mesh, and shotcrete lining. Overall, the tunnel is stable and does not have complex structure and weak zones.

ANTROPOMETRIC ANALYSIS OF ATATÜRK UNIVERSITY CAMPUS

Anthropometry is an important parameter that should always be considered in the architecture and landscape architecture professions, helping designers determine the bare minimum space required to accommodate the human body when performing outdoor/indoor related activities. Anthropometric analogies focus on the human body and its relationship to the design goal. Within the scope of the study, the concept of anthropometry was explained in the literature, and the relationship between Landscape Architecture and Anthropometry and anthropometric standards were examined. Atatürk University campus was chosen as the research area, and current applications were investigated in line with anthropometric data. The evaluation of landscape construction elements regarding anthropometric standards has been examined under two headings. These; consist of 1. Floor elements (Stairs, Ramps, Roads, Sidewalks, Flooring elements), 2. Equipment Elements (Lighting elements, Trash cans, Seating elements, Sign boards, limiters, and Vegetative elements). In this study, the ergonomic and anthropometric correct and incorrect applications of landscape reinforcement elements in the example of Atatürk University Campus were revealed, and suggestions were made on correcting the inaccurate and incomplete applications.

Creep compliance of functionalized graphene-epoxy nanocomposites

Creep behavior is observed even at room temperature in polymers and polymer composites under constant stress. In the design of structural elements using these materials, the determination of creep compliance for structural strength and performance analysis is crucial in terms of reliability and usability. In this study, the creep compliance of pure epoxy and functionalized graphene-reinforced epoxy nanocomposites were experimentally investigated and compared at room temperature at constant stress levels of 50, 100, and 200 MPa representing the viscoelastic region, yielding region and viscoplastic region, respectively. To reveal the effect of temperature as well as stress level on this behavior, the creep compliance of epoxy and graphene-epoxy nanocomposites was investigated at 65°C in addition to room temperature after the pure graphene used as a reinforcement element was functionalized with Triton X-100, nanocomposite production was carried out. In 2h creep tests, it was observed that as the constant stress level increased, the creep compliance increased and the creep compliance of the nanocomposite was lower than that of the epoxy at all stress levels. The creep compliance of the epoxy was improved by 65% with the addition of functionalized graphene at room temperature and a stress level of 100 MPa. As the temperature increased, the creep compliance of both epoxy and functionalized graphene-epoxy nanocomposite increased due to molecular mobility and viscous flow. However, at high temperatures, the positive effect of functionalized graphene on the compliance of the epoxy is higher. At 65°C and a stress level of 100 MPa, the improvement rate of creep compliance is 78%. Functionalized graphene exhibited a more effective behavior on creep resistance at high temperatures. The obtained results showed that creep compliance was significantly affected by stress level and temperature.

Physical and 3D numerical modelling of reinforcements pullout test

This paper reports results of laboratory and 3D numerical modeled pull-out tests with steel ladders and polymeric strip reinforcements. These types of reinforcement are commonly used in reinforced soil walls constructed with concrete facing elements. Laboratory pull-out tests are required to determine accurate and realistic pull-out strength values considering the interaction of specific reinforcement and backfill materials under different confining pressures (i.e., trying to simulate the different reinforcement layer arrangements and load conditions in actual reinforced soil walls). International design Codes for reinforced soil walls provide default values for pull-out strength. However, in many cases, default values are too conservative and/or are not strictly specified for particular reinforcement types. Pull-out tests can be difficult and expensive to perform, thus not being common nor worth for the vast majority of reinforced soil wall projects. Consequently, calibrated numerical models can be useful to predict pull-out response under site-specific conditions, and provide further understanding of the mechanisms involved in the soil-reinforcement interaction. Details of the numerical approach, including relevant aspects of the soil-reinforcement interfaces, are described. Examples of calibrated numerical predictions for pull-out loads, displacements, and soil-dilatancy effects are presented. The influence of reinforcement, soil and interface stiffnesses is shown. Numerical results provide useful insight for future modelling works of the complex interaction between type-specific backfill materials and reinforcement element, relevant for investigation and/or practical design of reinforced soil walls.

Investigation of mechanical properties of graphene-CNT reinforced nickel metal matrix nanocomposite structure

Nickel is a metal widely used in many industrial applications, but despite its superior properties, it also has some shortcomings. Carbon-based structures can be important reinforcement elements in improving the properties of metals. By providing a balance between the high corrosion resistance, high electrical conductivity and good magnetic properties of the nickel material and the lightness and high strength of carbon-based structures, a material with advanced properties can be obtained. Therefore, in this study, a new Nickel-Carbon nanostructure supported by a covalently bonded graphene-carbon nanotube (CNT) skeleton structure is presented. Additionally, three material designs with different geometric dimensions (Ni-G-CNT(5,5), Ni-G-CNT(10,10) and Ni-G-CNT(15,15)) were designed to determine the mechanical properties and properties of the structures in all directions. is to investigate the underlying deformation mechanisms. According to the results, it was observed that G-CNT structures increased the tensile and compressive behavior of the Ni structure in the CNT direction. For tensile loading in the CNT direction, as the CNT diameter decreases, the elastic modulus of the hybrid structures increases, while the maximum stress values are independent of the CNT diameter. As the CNT diameter increases, the ductility of the structures increases. In terms of compressive strength, it has been observed that in the linear region, as the CNT diameter increases, the strength generally increases and in the condensation region, it exhibits better compressive strength. With this study, an anisotropic nanostructure that is lighter and can exhibit higher tensile strength compared to the Ni structure is presented.

Investigation of Microstructures and Mechanical Properties of Al2024/6061/7075-Graphene Composites

This study aimed to compare the mechanical properties and microstructures of Al2024-graphene, Al6061-graphene, and Al7075-graphene composites produced by the powder metallurgy and induction heat treatment method. The effects of graphene content (0.15, 0.30, and 0.45wt.%), heat treatment (sintering and induction heat treatment), and matrix material (Al2024, Al6061, and Al7075) on the microstructure and mechanical properties of composites were investigated. Compared to Al2024, Al6061 and Al7075 alloys, the compressive strength of Al2024-0.15graphene, Al6061-0.15graphene and Al7075-0.15graphene composites increased by 33.74%, 24.9% and 32%, respectively. The highest hardness (164±1.5 HV), compressive strength (506±5 MPa), and apparent density (2.65 g/cm3) were achieved in sintered and induction heat-treated Al7075-0.15%graphene composite. As a result, it was determined that graphene is an effective reinforcement element. It has been determined that induction heat treatment improves the microstructure and mechanical properties of composite materials. Therefore, it has been stated that induction heat treatment significantly affects the mechanical properties of composites.