Use Of Composite Reinforcement Research Articles

Моделирование в программном комплексе СOMSOL Multiphysics напряжений и деформаций в клееной деревянной балке, усиленной композитной арматурой

The paper presents the results of the study on a model of a glued wooden beam with composite reinforcement. The authors use a software package using the finite element method COMSOL Multiphysics to model and study the stress-strain state of spatial multilayer wooden structures with reinforcement. The main focus is on analyzing the stress and strain characteristics of the beam under various loads. The paper considers the advantages of composite reinforcement efficiency and its influence on increasing the strength and durability of wooden structures. The authors pay special attention to the integration of experimentally obtained characteristics of wood and composite materials into the numerical model. It increases the accuracy of the modelling results. When constructing the 3D model, we have used a simplified wooden model as a transversal-isotropic body. It allows taking into account uncertainties on orientation to the tangential and radial directions in the beam. The results obtained confirm the increased load carrying capacity and reduced deformations in the beam due to the use of composite reinforcement compared to traditional wooden structures. The use of a 3D model of a glued beam with composite reinforcement also provides reduced research costs compared to in-situ experiments.

Benefits and risks of application of non-metallic composites as an alternative to steel reinforcement in concrete elements

The paper presents an overview of possible alternative reinforcement solutions to the most popular steel reinforcement currently used for concrete elements. Particular emphasis was placed on the use of composite reinforcement, taking into account the types of components concerned, possible applications and presenting an analysis of the risks and opportunities facing the construction industry related to the use of this type of reinforcement. In addition, an analysis of the material parameters taking into account the division of composite reinforcement due to the different types of fibers used in their production is presented. The paper also presents a comparative analysis of the parameters of steel and composite reinforcement, among others: tensile strength, susceptibility to corrosion, compressive and bending strength, fire resistance. It also analysed the needs of the construction market in the search for alternative concrete reinforcement in reinforced concrete structures, particularly in the context of recent events such as the Covid-19 pandemic and armed conflicts, which disrupt the supply chain and force the search for alternative materials that can replace reinforced steel. The availability of standards and instructions for the design of concrete elements and the related responsibilities of structural designers were analysed, identifying the research directions necessary to popularize and ensure the safety of the design of concrete elements with the use of alternative material solutions – in particular composite reinforcement in concrete slabs.

FEATURES OF STRENGTHENING BUILDINGS WITH THE LATEST REINFORCING MATERIALS

A good foundation ensures the reliability and durability of the building. In the absence of a fundamental base, the building can move, crack, and even bend, which as a result leads to uneven loads on the structure and destruction, therefore, the quality of the future structure depends on the quality of reinforcement. The use of composite reinforcement to strengthen buildings during restoration after destruction is advisable due to greater tensile strength, and also makes it easier to build due to less weight of reinforcement compared to steel. Good corrosion resistance characteristics of composite reinforcement in comparison with steel extend the life of reinforced concrete products (foundations, slabs, etc.). The type, method of connection and material of reinforcement is selected for each structure separately, and the choice depends on the type of soil, slope, size of the house, number of floors. Strengthening helps to reduce the likelihood of destruction, as well as some types of reinforcement help to eliminate irregularities and cracks on the walls during finishing work. Thanks to the correctly selected material for reinforcement, it is possible to accelerate construction. Purpose. Analyze materials for building reinforcement taking into account corrosion resistance and tensile strength. Conclusion. During the study, an analysis of reinforcing materials was carried out to strengthen the foundation and walls of buildings. Reinforcement helps to build the correct architecture of the structure and strengthen important parts to prevent destruction. It was found that reinforcement of composite materials has better characteristics than similar steel. Basic advantages: corrosion resistance and better mechanical characteristics. The design stress of the composite reinforcement under 10 kN load is 509.6 MPa which is less than the permissible − 800 MPa, and at elevated temperatures of tensile experiments the mechanical properties of the composite reinforcement change.

КОМПОЗИТНА АРМАТУРА В БУДІВЕЛЬНІ ГАЛУЗІ:ТЕНДЕНЦІЇ РОЗШИРЕННЯВИКОРИСТАННЯ

Scientific and technical progress largely ensures the production and use of new effective building construction materials with predetermined properties. The article considers the prospects of using a relatively new modern material in construction -composite reinforcement (AC), which has anumber of advantages compared to traditional metal reinforcement and at the same time is characterized by properties that limit its use in the production technology of modern concrete structures. In connection witha number of circumstances associated with the expansion of the operating conditions of reinforced concrete structures in highly aggressive environments, where it is difficult to ensure the corrosion resistance of steel reinforcement, composite reinforcement is used. The prospects of using composite reinforcement in ensuring the dielectric properties of some products and structures are shown. The global experience of using AK is summarized, the modern regulatory framework for its use in modern construction isgiven. It is shown that the use of AK on a par with steel reinforcement according to current standards regarding mechanical, technological and operational properties is sufficient to solve the vast majority of construction tasks. Reasons for the expansion of the use of composite reinforcement,taking into account the high energy intensity of traditional steel reinforcement and the inevitability of reducing greenhouse gas emissions in accordance with Ukraine's international obligations, are given.

Centrifugal concrete poles for transmission lines reinforced with prestressed FRP rebar

Reinforced with steel rebar concrete centrifuged conical poles for power transmission poles receive corrosion damage to steel reinforcement during operation. These damages can lead to the failure of structures. Complete replacement of both longitudinal and transverse steel reinforcement by composite one is a way to increase the reliability and durability of such structures. This method also allows the use of cost-effective concretes with a low cement content. The research results have shown the viability of such solutions, but the use of composite reinforcement requires its prestressing. This article discusses the Russian practice of testing concrete centrifuged conical poles for strength, crack resistance and rigidity. A brief description of the prototypes and methods of their testing is given. The main results of bending tests of full-scale test samples are presented in the form of diagrams of their deformation. Analysis of the results showed that the test samples of poles are correspond to requirements of Russian norms for deformability, crack resistance and strength. According to the results the studied centrifugal concrete poles with prestressed longitudinal GFRP rebars and transverse spiral GFRP rebars are like traditional ones with steel reinforcement (in standardized strength, crack resistance and deflection values) and, therefore, can be used in building construction.

JUSTIFICATION OF REINFORCEMENT PARAMETERS FOR PRODUCTS MADE OF NATURAL STONE WITH STEEL AND COMPOSITE CORES

Purpose. The objective of this study is to investigate the feasibility of using steel and composite reinforcement to enhance the strength characteristics of products made of natural stone. Methodology. The preparation of specimens for conducting strength tests is performed and described. Recommendations are provided for the preparation, configuration, and utilization of the main tools and materials involved in the research. The components of the experiment aimed at determining the strength characteristics of the specimens are developed and described. Based on the obtained data, calculations of the primary force parameters during the failure of the specimens under bending loads are carried out. Results. The research findings on the application of steel and composite reinforcement methods to improve the strength properties of stone products revealed that the use of composite reinforcement consistently increases deformation under higher loads, indicating better control of plastic deformation compared to steel reinforcement. However, the ultimate strength and load-bearing capacity of specimens reinforced with composite reinforcement are lower than those reinforced with steel reinforcement. Scientific novelty lies in the systematic analysis and comparison of the effectiveness of different types of reinforcement in enhancing the strength characteristics of products made of natural stone, as well as in the development of methodology and experimental procedures for determining force parameters. The obtained results indicate the potential of composite reinforcement for controlled plastic deformation and establish limitations regarding ultimate strength and load-bearing capacity. Practical significance of the research lies in providing recommendations and information that can be utilized by designers, engineers, and construction professionals in the manufacturing of products made of natural stone, as well as in the planning and implementation of construction projects involving natural stone.

The impact of percentage content of basalt fiber-reinforced polymer and steel reinforcement on the strength indicators of experimental beams with hybrid reinforcement

The use of composite reinforcement in the structures subject to bending is limited due to their excessive deformation. One way to overcome this shortcoming is to use hybrid reinforcement where steel and composite reinforcement are used in combination. The effectiveness of this approach has been proven by previous studies. There are no studies on the establishment of the effective ratio between steel and composite elements. This paper presents the results of tests of prototype beams with hybrid reinforcement made of basalt fiber-reinforced polymer (BFRP) and steel. A total of 12 series of samples of beams, three beams in each series, were studied. The percentage of both types of reinforcement was variable; it varied from a ratio of 100% / 0% to 0% / 100% in increments of ~ 20% (the numerator of the fraction corresponds to the percentage of steel reinforcement, and the denominator – to the percentage of BFRP reinforcement). According to the results of tests of beams by static loading, it was found that the use of hybrid reinforcement allowed to increase the bearing capacity of the samples by 33% – 74%, depending on the percentage of reinforcement in the cross section, compared with the beams of the control series. Based on the nature of breaks and load-bearing capacity, the most optimal ratio of steel and BFRP reinforcement was 60% – 40%. The optimal percentage of cross section reinforcement is 1.07%.

ON THE ADVANTAGES OF REPLACING STEEL REINFORCEMENT WITH COMPOSITE IN A REINFORCED BEAM

The article discusses the use of composite reinforcement in a composite concrete beam. The work of a bent single-span articulated beam is analyzed. A comparative analysis of the work of the beam with steel reinforcement, as well as composite. The economic substantiation of the obtained experimental results is carried out. The most optimal variant of the use of composite reinforcement in the construction is proposed.

Shaking table tests on gravel slopes reinforced by concrete canvas

The behaviour and performance of different reinforced slopes during earthquake loading were investigated through a series of shaking table tests. Concrete-canvas and composite reinforcement (geogrid attached to concrete-canvas) were proposed for reinforcing slopes. By considering the effects of different reinforcement methods, the seismic responses of the reinforced slopes were analysed, along with the accelerations, crest settlements, and lateral displacements. The failure patterns of different model slopes were compared using white coral sand marks placed at designated elevations to monitor the internal slide of the reinforced slopes. Both the concrete-canvas and composite reinforcement could increase the safety distance, which ranged from the slide-out point to the back of the model box. The composite reinforcement decreased the volume of the landslide and increased the failure surface angle as a result of the larger global stiffness in the reinforced zone. These results indicate that the recently developed concrete canvas has a better effect on restricting the slope deformation during seismic loading than the nonwoven geotextile reinforcement, and that the use of composite reinforcement could improve the seismic resistance of slopes.

Особенности применения композитного армирования в фундаментах малоэтажных зданий

The article identifies the features of the use of composite reinforcement in the pile and strip foundation of a two-story house. When designing the foundations, the complex geological conditions of the construction site were taken into account: a high level of groundwater, their aggressiveness with respect to metal reinforcement (seasonal fluctuation of water supply and water treatment at the time of engineering and geological surveys at a level of 2.8 m); the possibility of landslide processes on the slopes; insufficient knowledge and anisotropy of the properties of the bulk layer, significant thickness of the bulk layer, excluding its removal and replacement. An analytical calculation and a numerical experiment were carried out, the following features of the use of composite reinforcement were established:
 more effective in strip foundations is fiberglass reinforcement, resistant to aggressive influences; ASK is advisable to use only in lightly loaded pile-tape foundations, or with a small pitch of piles due to low rigidity characteristics of ASK. With a significant load on the structures, it is recommended to use combined reinforcement: in areas of pure compression and tension using ASK, and in bending zones - metal reinforcement.

Fire Resistance Of Concrete Structures With Composite Rod Reinforcement

The use of composite rod reinforcement makes it possible to ensure the durability of reinforced concrete structures, operated under aggressive conditions. The use of composite reinforcement in concrete structures requires solving the problem of fire resistance of this class of structures. The fire resistance of the composite rod reinforcement is determined by the moment of softening of the composite rod matrix as a result of heating under fire conditions. The maximum temperature for various composite materials is 150 °Ñ – 250 °C. When designing, it is necessary to ensure the normative value of the limit of fire resistance of structures. For the bearing structures of the frame, the fire resistance limit corresponds to the moment of loss of the bearing capacity, for the intermediate floors – the loss of bearing capacity, integrity and thermal insulation ability. The main factor that provides the fire resistance of concrete structures with rod composite reinforcement is the thickness of the protective layer of concrete which ensures the joint operation of composite rods with concrete. Diagrams of the temperature change over the thickness of a concrete structure are presented, on the basis of them the methodology for the assignment of the value of the protective layer of concrete for the core composite reinforcement for different designs with due regard for the duration of fire effect in case of fire is proposed. The nomenclature of structures in which it is possible to use the rod composite reinforcement with the provision of regulatory requirements for the limit of fire resistance is determined.

Model of stressed-strained state of multi-layered reinforced concrete structure with the use of composite reinforcement

The development in calculating reinforced concrete structure method covers a wide range of issues, including the expansion of fields such as application of new innovative materials which consist of concrete and reinforcement . In order to apply modern construction of multi-layer structure using concrete with different mechanical and physical characteristics, it is compulsory to conduct researches on the stressed-strained state of these structures under various types of load, which is determined not only by the stressed-strained state of the multi-layer reinforced concrete structure, but also by the properties of the reinforcement.The object of the study is multi-layer reinforced concrete structures of concrete with various physical and mechanical characteristics of materials - concrete and reinforcement under the influence of various types of loading. The subject of this study is the fluctuation in the stress-strain state under loadings of multi-layer reinforced concrete structures with the use of composite reinforcement. Studies related to the use of composite reinforcement in multi-layer structures have not been carried out, which significantly limits the scope of its application.The methods of investigation are based on numerical modeling of stresses and deformations of multi-layer reinforced concrete elements under the action of different combinations of loads. The use of modern software systems allows a number of studies, combining different combinations of loads and the variability of the strength and deformation characteristics of materials in structural concrete or in low strength concrete for the middle layer and various types of metal or composite reinforcement . In order to precisely calculate and measure these materials, the physical and mechanical properties of materials are used, which are determined on the basis of normative data or experimental studies. Numerical simulation makes it possible to compare the results obtained and construct theoretical dependencies in a wide range of specified parameters for constructing cross sections of multi-layer reinforced concrete elements. The range of this research is limited in the short-term load effect of reinforced concrete.The obtained scientific results allow determine rational parameters for modeling various design solutions of multi-layer reinforced concrete structures. The practical importance of the research will expand the areas of rational use of multi-layer reinforced concrete structures and ensure safe operation throughout the life cycle of buildings and structures using multi-layer structures.

Strength of Circular Concrete Columns Reinforced with FRP Bars and Spirals

Circular cross section reinforced concrete columns are often used in structures of buildings, ports or bridges. Generally, for the installment of these constructions metal/steel reinforcement is being used. Corrosion of steel reinforcement is the main and one of the biggest problems reducing the durability of these structures and it is a reason of fragile disintegration of these structures. In the current period, the composite reinforcement is an alternative material for the production of reinforced concrete structures the mechanical characteristics of which are equal to or even better in comparison of the commonly used steel reinforcement characteristics, including tensile strength and resistance to corrosion at the extremely aggressive environment. Due to the lack of the researches, many design standards do not indicate or recommend the use of composite reinforcement in compressive elements or flexural elements in compressed zones. This article analyzes the possibilities of the use of composite reinforcement in axially crushed circular cross section columns.

Fatigue testing of composite patches for ship plating fracture repair

ABSTRACTThe objective of this study is to examine, through physical testing, the use of composite patches for preventing crack growth and extending the service life of ship plating. Fatigue tests were conducted on steel plates to experimentally validate the effectiveness of using composite patches as a means to prevent crack growth and extend the fatigue life of structural components. Specimens were tested with and without the use of composite reinforcements. Previous results of numerical analysis studies had indicated that a one- to two-order of magnitude increase in service life can be expected for the conditions tested. The experimental results presented here show increases closer to a single order of magnitude. The difference is attributed to two factors: failure mechanisms associated with debonding of the patch and cracking of the patch itself. Of critical importance, therefore, are the implementation of a quality-controlled bonding procedure and optimisation of the geometry and properties of the patch systems based upon the parent plate's properties and fracture conditions.

Tensile Strength Matrix Composite Waste Glass Fiber Reinforced Plastics

Polypropylene (PP) including a type of plastic which ranks second on the most number of types of plastic waste after the type of High Density Polyethylene (HDPE). Glass fibers have superior mechanical properties of natural fibers. Because it has good mechanical properties, glass fibers currently plays an important role in the use of composite reinforcement. Mechanical properties of glass fiber owned and PP waste in environmental conditions that more conditions, it can be utilized as a composite reinforcement and matrix materials. This research was conducted by of injection molding method. The comparison between the volume fraction of the glass fiber matrix of type PP plastic waste with variation 0% fibers 100% matrixs, 10% fibers 90% matrixs, 20% fibers 80% matrixs, 30% fibers 70% matrixs, 40% fibers 60% matrixs, and 50 % fibers 50% matrixs. The optimum conditions obtained in this study was the comparison of variation occurs in 50% fibers volume fractions of 50% matrixs were: tensile stress was 24.30 N/mm2, tensile strain was 13.60%.

RESEARCH OF EFFICIENCY OF USING CARBON FIBER IN ARNORED CONCRETE SPANS OF RAILWAY BRIDGES

Purpose. This work presents using carbon fiber as composite rebar by way of rods of fittings for reinforcement armored concrete span 13,5 meter length compared to same-length span with usual fixture. Methodology. The calculation is carried out as described in the methodological guidelines for the design and calculation of concrete span with frame-welded fittings. Findings. On the basis of the above study was to determine how the use of composite reinforcement as working for the reinforcement of its span. Originality. The possibility of using composite rebar as an element that works in tension in the span was proved. Practical value. Install valves of this type will reduce the cost of the span and increase its operating period.

Use of Composite Reinforcement to Strengthen Concrete and Air-Entrained Concrete Masonry Walls against Air Blast

Two concrete structures and three air-entrained concrete (AEC) masonry walls were subjected to two, high explosive detonations. The concrete structures were placed at a stand-off distance such that medium damage was expected. The stand-off distance of the AEC-masonry walls was reduced on each successive detonation until breaching occurred. The two concrete structures retrofitted with composite materials were subjected to air-blast loading at a stand-off distance of approximately 14.6 m. The structures were constructed such that each long side of the structure contained a wall retrofitted with a composite material and a wall left bare as a control. Both concrete structures exhibited less residual displacement on the walls strengthened with composite materials than the bare control walls.