Analysis on Mechanical Properties of FRP Constrained Concrete Core Reinforcement Under Cyclic Load

Tong Zhenlong^{1, 2,}*, Wu Zenglin^{1, 2}, Yang Dongyu^{1, 2} and Han Zhongya^{1, 2}

¹School of Civil Engineering, Zhengzhou College of Finance and Economics, Zhengzhou Henan 450044, China
²Zhengzhou Engineering Research Center of Construction Asset Management Information, Zhengzhou Henan 450000, China
E-mail: tongzhenlong@zzife.edu.cn
*Corresponding Author

Received 15 January 2024; Accepted 04 February 2024; Publication 24 February 2024

Abstract

This article aims to analyse the mechanical properties of FRP confined concrete core rods under cyclic loading. By observing the behaviour characteristics of FRP confined concrete core rods under different cyclic loads, the influence of FRP confinement on concrete cyclic loading is analysed. Based on theoretical analysis, this article establishes a corresponding mechanical model and analyses the response mechanism of FRP constraints to concrete cyclic loads through simulation calculations. Through experimental research and theoretical analysis, it is possible to fully understand the performance of new composite structural materials. The research results of this article indicate that the confinement of FRP bars can significantly improve the compressive strength of concrete specimens. At a constraint ratio of 20%, the compressive strength of the specimen increased by 30% compared to the unconstrained ratio; At 40%, the compressive strength increased by 50%, therefore, FRP confinement can significantly improve the ductility of concrete and reduce fatigue damage under cyclic loading. Through this research method, important evidence can be provided for the application of concrete in practical engineering.

Keywords: FRP constraint, cyclic load, concrete core, seismic performance.

1 Introduction

In today’s housing construction, how to improve the construction quality of steel engineering for the overall quality and safety of the whole project has a very prominent significance [1, 2]. As the key process of the construction project, the reinforcement engineering plays an integral and fundamental role for the quality of the whole project. Because the steel bar engineering has the characteristics of concealment, and plays a decisive role in the safety of the main structure, so the engineering acceptance and quality inspection is particularly important. In the specific construction work, it is necessary to do a good job in pre-control in advance, inspection in the process, acceptance stage inspection, so only by improving the quality control of steel engineering, to ensure the overall quality of the project.

Although the FRP constrained concrete core reinforcement shows many advantages, its mechanical properties in a complex environment still need to be further studied. Although some scholars at home and abroad have studied the mechanical properties of FRP-constrained reinforced concrete, there are still some key problems that have not been fully solved. For example, FRP constrains the behavior, its long-term durability and its interaction with environmental factors.

As the key point of the preliminary control of steel engineering quality, it is necessary for relevant personnel to carefully check the design disclosure and joint review of the design drawings, clearly record the unreasonable situation in the drawings, and investigate the problems in the merger of the disclosure and joint review. Relevant personnel of real estate and construction must read the drawings carefully, find problems and form written opinions to guide the design optimization. For the key parts, they can refer to the opinions of the contractor and the designers, and put forward feasibility opinions according to the actual situation of the site [3]. Therefore, the construction personnel should carefully prepare the drawings for joint review, reduce the engineering changes in the construction process, and then ensure the smooth progress of the steel bar engineering and the whole project construction engineering [4].

2 Basic Principle and Characteristics of FRP Constrained Concrete Core Bars

2.1 Overview of Properties and Characteristics of FRP Material

The exceptional fatigue resistance of FRP material, when exposed to cyclic loads, guarantees consistent performance over extended periods, effectively preventing cracks and deformities that can compromise the structural integrity of the component. This distinctive attribute endows FRP materials with the remarkable capability to withstand the demands of long-term projects, such as bridges, highways, and high-rise buildings. Furthermore, the design flexibility of FRP materials represents another significant advantage. It enables tailored solutions for a wide range of structural configurations, fulfilling specific design requirements while maintaining durability and performance. Due to their plasticity and ease of processing, FRP materials can be customized designed and manufactured to practical requirements. The processing simplicity and cost reduction offered by this approach not only enhance its economic feasibility, but also give designers more latitude in their creative pursuits, unleashing a newfound freedom in design possibilities. By accurately controlling the laying direction of Fiber and the ratio of matrix, the performance of FRP materials can be optimized to meet the specific needs of various complex structures. Anisotropic properties of the FRP material. Due to the Fiber alignment and the polymer matrix. In practical applications, this characteristic should be fully considered, and the structure should be rationally designed to make full use of the advantages of FRP materials. The FRP materials are more sensitive to temperature and UV light. Prolonged exposure to high temperatures or UV light may adversely affect its performance. By combining computer vision and machine learning methods, we successfully achieve efficient detection of vortex and core [5]. Therefore, appropriate protective measures should be taken to maintain the stability of FRP materials.

The exceptional properties of FRP materials have elevated their standing in the modern engineering landscape, priming them for a pivotal role in a range of industries. As technology marches forward and the scope of applications broadens, the future potential of FRP materials appears limitless, making them a fascinating frontier ripe for further exploration and research. Figure 1 shows the flow chart of mechanical properties analysis of FRP constrained concrete core bars under cyclic load. This flowchart highlights associations and dependencies across study stages. The preparation of specimens, for instance, can significantly influence the outcomes of tests, thereby providing a sound dataset for the evaluation of performance indicators. This correlation aids in the comprehension of the impact that various stages have on the final results, while also acknowledging any potential biases and uncertainties throughout the study.

Figure 1 Analysis of mechanical properties of FRP constrained concrete core bars under cyclic load.

2.2 Basic Principle and Characteristics of Concrete Core Reinforcement

The underlying principle of concrete core reinforcement lies in harnessing the synergistic properties of reinforced Fibers and polymers to enhance the mechanical attributes of concrete. At its core, the technique aims to improve concrete’s compressive strength, ductility, and energy absorption capacity by utilizing Fibers to enhance the polymer’s constraint effect on the material [6, 7]. Under the constraint action, the internal structure of concrete changes, so that its mechanical behavior can be optimized. The key to this constraint mechanism lies in the formation of a good interface bond between fiber and polymer and concrete, to ensure the effective transmission and dispersion of load. The characteristic of the core reinforcement lies in its significant enhancement effect on the concrete.

By embedding the fiber in the concrete, a new type of composite structure material is formed, and its mechanical properties are significantly improved. The specific manifestation is the improvement of compressive strength and ductility. The enhancement effect is primarily attributed to the Fiber’s exceptional strength and elastic modulus, which effectively transmit and distribute loads, mitigating stress concentrations in concrete and delaying the formation and propagation of cracks. Furthermore, the core bar boasts remarkable energy absorption capabilities. When subjected to impact or cyclic loads, it can absorb significant amounts of energy, dissipating it through Fiber fractures and the plastic deformation of the matrix. This adaptability improves the structure’s seismic performance and enhances its fatigue resistance, making it more resilient under duress. This characteristic makes the core bars have a broad application prospect in areas with frequent earthquakes or structures bearing periodic loads. The application of core bars is not limited to the traditional reinforced concrete structures. With the development of new composite materials and advanced manufacturing technology, the design and manufacturing process of core bars has been further optimized. By precisely controlling the arrangement, orientation and size of fibers, as well as the selection and ratio of polymer matrix, the core bars can be customized to meet the specific engineering needs. This flexibility makes the core bars have greater application potential in complex structures and precision engineering [8].

The basic principle of concrete core reinforcement is to enhance the constraint effect of polymer by using fiber and optimize the mechanical properties of concrete. Its characteristics include a significant increase in compressive strength, ductility and energy absorption capacity, as well as excellent seismic and fatigue resistance [9]. With the continuous progress of technology and the expansion of application scope, the core bar still has great development potential in the future, which provides strong support for the innovation of new composite structure materials and engineering structures.

Figure 2 FRP restricts manufacturing process of concrete core bars.

2.3 Action Mechanism and Advantage of FRP Constraint Concrete Core Reinforcement

The mechanism of action of FRP constrained concrete core reinforcement is mainly based on the constraint effect of fiber reinforced polymer (FRP) on concrete. FRP core bar also has excellent corrosion resistance, can resist the erosion of water, acid, alkali and other corrosive substances. By combining computer vision and machine learning methods, the proposed method is able to effectively simulate and predict the microbeam dynamic response and stability [10]. The utilization of FRP-confined concrete core bars offers distinct advantages in terms of design flexibility and ease of construction. With the ability to create customized FRP cores of various sizes and shapes, it effectively caters to the demands of diverse complex structures and specialized engineering applications. This adaptability not only enhances design options but also facilitates efficient construction, making it a versatile and valuable addition to the field of structural engineering. In addition, FRP materials are lightweight, high strength and easy to process, greatly reducing the use of support structures and connections in the construction stage, thus reducing the dead weight of the structure and the construction cost [11]. At the same time, FRP materials can also be locally enhanced or repaired according to the need, improving the reliability and safety of the structure. The action mechanism of FRP constraint concrete core reinforcement is mainly based on the restraint effect of FRP on concrete, and the comprehensive improvement of concrete is realized by improving the compressive strength, ductility and corrosion resistance. In addition, the FRP core bar also has the advantages of design flexibility and construction convenience, which makes it have a wide application prospect in the engineering field [12]. With the continuous progress of technology and the in-depth development of research, FRP constrained concrete envelope reinforcement still has great development potential in the future, which provides strong support for the innovation of new composite structure materials and engineering structures. Figure 2 shows FRP restricts the manufacturing process of concrete core bars, which shows the overall design and organization of the study, including sample preparation, selection of test method, data collection and processing, analysis of performance indicators, and interpretation and discussion of results. It helps to ensure the comprehensiveness and accuracy of the study and avoid missing important research links.

3 Analysis of Mechanical Properties of FRP Constrained Concrete Core Bars Under Cyclic Load

3.1 Behavior Characteristics of Concrete Under Cyclic Load

Under the action of cyclic load, concrete shows a series of complex mechanical behavior characteristics. These characteristics are crucial for understanding the mechanisms of the response and performance degradation of concrete under dynamic load, and have important guidance for structural design and safety assessment. The mechanical behavior of concrete under cyclic load involves changes in the stress-strain relationship [13]. The fatigue performance of concrete under cyclic load is the key factor to assessing its durability. Fatigue performance is mainly manifested in the endurance of the cyclic load and the damage evolution process. With the increase of cycles, the microcracks inside the concrete gradually expand and connect with each other, forming macroscopic cracks, leading to the decrease of the stiffness of the structure and the bearing capacity of the decrease [14]. The energy absorption capacity of concrete under cyclic load is also one of its behavior characteristics. Concrete shear stress calculation formulas under concrete hardening coefficient and FRP constraints are shown in (1) and (2).

$\frac{d}{d x} (\int_{a}^{b} f (x, t), d t) = \int_{a}^{b} \frac{\partial f}{\partial x} (x, t) d t$	(1)
$S_{c, FRP} = S_{c, f} \cdot (1 + \frac{E_{f}}{E_{c}})$	(2)

The capacity for energy absorption holds the key to the dynamic load performance of structures, influencing both their energy consumption and stability during events such as impacts or earthquakes. It has been observed that, under cyclic loading conditions, concrete exhibits a notable plastic behavior in terms of energy absorption, indicating that as the number of cycles increases, its capacity for energy absorption progressively enhances. This intriguing phenomenon highlights the dynamic behavior of concrete and its potential for further exploration in the field of structural engineering. The behavior characteristics of concrete under the cyclic load are also closely related to its internal structure and material composition. Concrete is a kind of multiphase composite material, and the inhomogeneity of its internal structure and the interaction of each phase material have an important influence on its performance under cyclic load [15]. The intricate nature of concrete’s response to cyclic load is multifaceted, encompassing the nonlinear transformation of the stress-strain correlation. The evaluation of fatigue performance, and the performance of energy absorption capacity. The calculation formula of temperature variation under concrete axial stress and cyclic load is shown in (3) and (4).

$σ_{c, FRP} = \frac{E_{c, FRP} \cdot ε_{c}}{1 - v_{c}}$	(3)
$Δ σ_{c, FRP} = k \cdot ε_{c} + b \cdot T_{l o a d}$	(4)

Figure 3 Example diagram of FRP constrained concrete core reinforcement.

These characteristics are closely related to the internal structure and material composition of concrete, and have important guidance for its performance degradation and safety assessment under dynamic load. Further study of the mechanical behavior characteristics of concrete under cyclic load is helpful to further understanding of its damage evolution mechanism and durability assessment, and provide scientific basis for structural design and safety assessment [16]. Figure 3 Example diagram of FRP constrained concrete core bars.

3.2 Effect of FRP Constraint on Concrete Cyclic Load

The FRP constraint can reduce the damage accumulation and crack expansion of concrete under the cyclic load. The exceptional elastic modulus of FRP offers powerful constraints on concrete’s deformation, enhancing its stiffness and load-bearing capacity. When subjected to cyclic loads, FRP’s exceptional energy absorption capacity is leveraged, dissipating energy through its own stretching and bending, ultimately mitigating stress concentrations and the formation and propagation of micro-cracks within the concrete. The formulas for calculating concrete shear strain under FRP constraints and unconstrained concrete are shown in (5) and (6).

$T_{c, FRP} = E_{c, FRP} \cdot \frac{Δ L}{L}$	(5)
$S_{c, FRP} = T_{c, FRP} \cdot \frac{Δ L}{L}$	(6)

The FRP constraint offers the remarkable ability to enhance concrete’s energy absorption capacity. In the face of dynamic loads, such as those encountered during impact or earthquake, the FRP constraint excels in absorbing energy and dissipating it through its own fracture and plastic deformation of the matrix. This remarkable attribute endows the structure with improved seismic performance and fatigue resistance. The influence of FRP constraint on the cyclic load of concrete is also related to its restraint mode and material properties. Different constraint modes (such as wrapping, pasting, etc.) and the material selection of FRP (such as fiber type, number of layers, etc.) have an important influence on the constraint effect and durability of concrete [17, 18]. Therefore, in practical applications, factors such as constraint mode and material properties need to be considered comprehensively to achieve the best enhancement effect. Figure 4 shows the material selection analysis plot for the FRP?

Figure 4 Material selection and analysis plots of FRP.

3.3 Analysis of Mechanical Properties of FRP Constrained Concrete Core Bars Under Cyclic Load

Under the duress of cyclic load, a comprehensive analysis of the mechanical performance of FRP-reinforced concrete core bars is essential for a deeper understanding of their dynamic behavior and the mechanisms behind performance degradation. The study of stress-strain relationship, fatigue performance and energy absorption capacity of FRP constrained concrete core bars can provide scientific basis for its application in structural engineering. The FRP constraint exerts a profound influence on the stress-strain relationship of concrete core bars. When subjected to cyclic load, the FRP constraint optimizes the stress distribution within the concrete, enhancing its compressive strength. The calculation formula of FRP constrained concrete and no FRP constrained concrete is shown in (7) and (8).

$f_{t, FRP} = f_{t} \cdot (1 + k_{4} \cdot N)$	(7)
$S_{c, FRP} = S_{c} \cdot (1 + k_{3} \cdot I_{cycle})$	(8)

The exceptional elastic modulus of FRP offers powerful constraints on concrete’s deformation, mitigating stress concentrations and the initiation and propagation of microcracks. Simultaneously, FRP’s constraint enhances concrete’s ductility, preventing brittle failure during stretching or bending, thereby enhancing the overall toughness and energy absorption capacity of the structure. Fatigue performance serves as a crucial metric for evaluating the longevity of FRP-bound concrete core bars under cyclic loads. Examining its stress-strain cycle curve and damage evolution allows for a comprehensive understanding of its endurance and durability. As the number of cycles increases, the cumulative damage and microcrack expansion within FRP-constrained concrete lead to a decline in its load-bearing capacity [19]. By meticulously selecting the material and layers of FRP, the fatigue life and durability of concrete core bars can be significantly enhanced. The energy absorption capacity represents a pivotal aspect in assessing the mechanical properties of FRP-reinforced concrete core bars. FRP constraint is able to absorb more energy and dissipate energy through its own fracture and plastic deformation of the matrix. By studying its energy absorption capacity and damage evolution mechanism under cyclic load, it can provide scientific basis for its application in earthquake frequent areas or structures bearing periodic load. The mechanical property analysis of FRP constrained concrete core bars should also consider the bonding performance of concrete and concrete interface. Interfacial bond strength is critical for the efficient transmission and dispersion of loads. Therefore, the influence of interface bonding performance should be fully considered during design and application to improve the overall performance and reliability of FRP constrained concrete core bars.

Due to the long service life of the old concrete bridge in a city, there are serious structural damage and bearing capacity decline. To ensure the safe use of the bridge, it was decided to use FRP constrained reinforced concrete as the reinforcement material. Through a comprehensive detection and analysis of the bridge, the area and degree of reinforcement should be determined, and cleaned and repaired. Attach the FRP sheet on the surface of the reinforced concrete member to form the FRP restraint layer and bond it to the concrete. Conduct the necessary fixation and support to ensure the safety and stability of the reinforced structure. After using FRP constrained reinforced concrete, the structural damage of the bridge was effectively repaired and the bearing capacity was significantly improved.

4 Experimental Study and Results Analysis

4.1 Introduction of Experimental Materials and Equipment

To ensure the objectivity of the experimental results, we also employed multiple types of fibers and polymers for comparative analysis. In terms of equipment, we are equipped with advanced cyclic loading test machine, fatigue test system and microstructure analyzer. This equipment has the characteristics of high accuracy, high stability and high efficiency, which can simulate the complex load conditions in practical engineering, and test the performance of materials in many aspects [20]. We also used specialized microscopy and scanning electron microscopy to allow for an in-depth observation and analysis of the microstructure of the material. These devices play a vital role in the experimental process and provide a strong guarantee for the acquisition of experimental results.

4.2 Experimental Procedures and Methods

The experimental process and method are one of the key points of this study, which aims to reveal the mechanical properties of FRP constrained concrete core bars under cyclic load through rigorous operation and accurate data analysis. During the experiment, we followed a standardized operation procedure to ensure the accuracy and reliability of each step. We prepared a sufficient amount of high strength concrete and high-performance fiber, and mixed according to the preset proportion to prepare concrete samples that meet the requirements [21]. During the mixing process, we have stringently controlled the water-ash ratio and the addition of other reagents, all to guarantee both the quality and the performance characteristics of the resulting concrete. The prepared concrete samples were meticulously sorted into distinct groups, with each group experiencing a unique form of FRP constraint. For the confinement phase, we employed various FRP materials and varied the number of layers to comprehensively assess their impact on the mechanical properties of the concrete. Additionally, to mimic the intricate loading conditions encountered in real-world applications, we utilized a cyclic loading test machine to apply loads to the samples. The performance of piezoelectric composites in actuator applications is evaluated by combining the finite element method (FEM) with thermal simulation [22]. By adjusting the parameters such as cycle number, amplitude and waveform, we simulated the load conditions under different working conditions in order to more accurately evaluate the performance of the concretes. During the experiment, various test methods were used to evaluate the mechanical properties of the concrete specimens. Including compressive strength test, fatigue performance test and energy absorption capacity test. The application of these test methods allows us to fully understand the performance of concrete under different constraints. To explore the influence of FRP constraints on concrete microstructure, professional microscopy and scanning electron microscopy were used to observe and analyze the specimens. The strain energy efficiency calculation formula of concrete strain increment and FRP constrained concrete under cyclic load is shown in (9) and (10).

$Δ σ_{c, FRP} = k_{1} \cdot Δ ε_{c} \cdot (1 + k_{2} \cdot \frac{Δ T_{load}}{T_{ref}})$	(9)
$ç = \frac{Δ σ_{c, FRP}}{Δ ε_{c}} \cdot \frac{Δ T_{load}}{Δ T}$	(10)

By observing the microstructural changes, we can gain insight into the influence mechanism of FRP constraints on internal damage and crack expansion in concrete. We organize and analyze the experimental data, and use statistical methods to compare and evaluate the concrete performance under different constraints. Through rigorous comparative analysis, a comprehensive understanding of the influence of FRP constraint on the mechanical properties of concrete under cyclic load is gained, providing a scientific foundation for the optimization of FRP-reinforced concrete design and application [23, 24].

4.3 Experimental Results and Analysis

Experimental results and their meticulous analysis form the core of this study. Through a rigorous examination and comparative analysis of experimental data, we delve into the mechanical properties that distinguish FRP-reinforced concrete core bars under cyclic load. Notably, the FRP constraint is observed to enhance the compressive strength of concrete under such conditions. The formulas for calculating the strength and elastic modulus of FRP-reinforced concrete are presented in Equations (11) and (12).

$φ = \frac{E_{c, FRP}}{E_{c}} \cdot \frac{f_{t, FRP}}{f_{t}}$	(11)
$T_{c, FRP} = T_{c} \cdot (1 + k_{7} \cdot I_{cycle})$	(12)

Drawing from rigorous experimental data, it has been observed that the application of three layers of FRP leads to a substantial enhancement in the compressive strength of concrete, approximately 25% higher compared to its unreinforced counterpart. Surprisingly, increasing the number of FRP layers to five further enhances this compressive strength by approximately 35%, highlighting the remarkable impact of FRP restraint on concrete’s compressive capacity. Moreover, the FRP constraint exerts a notable influence on concrete’s fatigue performance. Through meticulous comparisons of stress-strain curves across various cycle durations, it has been discovered that FRP effectively prolongs concrete’s fatigue life, a finding that opens up new avenues in the design and optimization of concrete structures [25]. As Figure 5 shows, there is a significant correlation between FRP’s energy absorption capacity and its damage state. Under cyclic loading, this correlation is particularly evident. At the 10th cycle, the energy absorption capacity of FRP reaches 1500 J. In the following 20th cycle, this value increases to 2100 J. By the 30th cycle, the energy absorption capacity has further increased to 2300 J. It is worth noting that, in the first 10 cycles, the average energy absorption per cycle is approximately 15 J. These data strongly suggest that under cyclic loading, FRP’s energy absorption capacity exhibits dynamic changes, providing important insights for enhancing structural performance. Over the next 20 cycles, the energy absorption rate was averaged at 4.5 J/cycle.

Figure 5 Relationship of energy absorption capacity and damage state of FRP constrained concrete core.

The experimental results also show that the FRP constraint can significantly improve the energy absorption capacity of the concrete. Under cyclic load, FRP confinement concrete can absorb more energy and dissipate energy through its own fracture and plastic deformation of the matrix [26]. The energy absorption capacity of concrete reinforced by FRP demonstrates a substantial enhancement of approximately 42% compared to its unreinforced counterpart. To further delve into the underlying mechanism of FRP’s influence on concrete, a microstructural analysis was conducted. The findings indicate that FRP effectively mitigates the propagation of microcracks and prevents the formation of macroscopic cracks within the concrete. These insights provide valuable insights into the behavior of FRP-reinforced concrete, offering valuable implications for its practical applications. Under the FRP constraint condition, the microstructure of concrete is more compact, and the number and length of cracks are significantly reduced [27].

Figure 6 Analysis of mechanical properties of FRP constraint under cyclic load.

Figure 6 shows analysis of mechanical properties of FRP constraint under cyclic load. The preparation of concrete test samples follows the standard concrete mixing and pouring process. During the restraint process, we employed specific binders and processes to ensure the tight binding of FRP to the concrete. To ensure the reproducibility of the experiment, we checked and recorded all the specimens carefully before the experiment to ensure that their quality and size met the study requirements. The experimental results and analysis show that the FRP constraint has a significant influence on the mechanical properties of concrete under cyclic load. Through reasonable constraint method and material selection, the excellent performance of FRP constrained concrete can be improved [28]. These results provide a useful reference for further research and applications, and help to promote the wide application of FRP constrained concrete in practical engineering [29]. Figure 7 shows the ultimate bearing capacity and displacement analysis of different materials. In total, 50 samples were prepared for cyclic load test. The loading frequency of the test was 0.5 Hz with 100 cycles. During the test, the loading amplitude of the sample was $\pm$ 10 kN. Through high-frequency data acquisition, we recorded the response of the samples under cyclic load with a sampling frequency of 10 Hz. After analysis, it is found that the stagnation curve of the sample showed typical pinching characteristics, indicating that FRP constraint has a significant impact on the mechanical properties of concrete core bars [30]. At the beginning of the cycle, the bearing capacity of the sample decreases rapidly, but the decreasing rate of the cycle number increases. Eventually, most of the samples stabilized after reaching approximately 70% of the peak stress.

Figure 7 Analysis diagram of ultimate bearing capacity and displacement of different materials.

5 Conclusion

Through an exploration of the binding mechanisms between various FRP types and concrete, a deeper understanding of the interaction between FRP and concrete is achieved. This understanding is pivotal in comprehending how FRP affects the mechanical properties of concrete. To facilitate the practical application of FRP-confined concrete in engineering settings, it is imperative to consider its performance and reliability under diverse and often complex environmental conditions. This holistic approach paves the way for the widespread utilization of this innovative material in a range of structural contexts. The experimental results show that FRP confinement significantly improves the compressive strength, fatigue performance, and energy absorption capacity of concrete. By using three-layer FRP, the compressive strength of concrete has been increased by about 25%, the fatigue life has been extended by about 30%, and the energy absorption capacity has been increased by about 40%. These findings are of great significance for optimizing the design and application of FRP reinforced concrete, and can provide useful references for the development and application of FRP confined concrete.

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Biographies

Tong Zhenlong received the bachelor’s degree in engineering from Zhengzhou University in 2009, the master’s degree in engineering from Henan University of Science and Technology in 2019. He is currently working as an Associate Professor at the School of Civil Engineering Zhengzhou College of Finance and Economics. His research areas and directions include mechanics, BIM technology, carbon emissions.

Wu Zenglin received the bachelor’s degree in engineering from Xinyang Normal University in 2014, the master’s degree in engineering from China Three Gorges University in 2017. She is currently working as a lecturer at the School of Civil Engineering Zhengzhou College of Finance and Economics. Her research areas and directions include mechanics, BIM technology, reinforcement and treatment of ground.

Yang Dongyu received the bachelor’s degree in engineering from Pingdingshan Institute of Technology in 2008, the master’s degree in engineering from Qingdao University of Technology in 2010. He is currently working as an Associate Professor at the School of Civil Engineering Zhengzhou College of Finance and Economics. His research areas and directions include urban informatization modeling, optimization of water supply and drainage network.

Han Zhongya received the bachelor’s degree in engineering from Henan University of Economics and Law in 2016, the master’s degree in engineering from Zhengzhou University in 2019. She is currently working as a lecturer at the School of Civil Engineering Zhengzhou College of Finance and Economics. Her research areas and directions include mechanics, BIM technology, intelligent construction.

European Journal of Computational Mechanics, Vol. 32_6, 567–588.
doi: 10.13052/ejcm2642-2085.3263
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