Cracking and Crack Control in Circular Concrete Bridge Members Reinforced with Fiber-Reinforced Polymer Bars

Liu

et al. 2020

Applied Sciences

The temperature distribution is one of the most vital parameters which should be fully considered in high geothermal tunnel design. For the purpose of studying the impact of temperature disturbance caused by construction on temperature distribution of surrounding rock and lining structure in a high geothermal tunnel, a new finite difference model for temperature prediction was proposed. Based on the abundant field test results, forecast analysis for the research of a high geothermal tunnel in this paper is made. The results indicate that the temperature of the surrounding rock near the tunnel sidewall decreases obviously in the first 14 days while that of the surrounding rock far away is stable after tunnel excavation, and the rock temperature showed three ways of change: undulate type (<2 m), decline type (2–5 m) and stable type (>5 m). There is a linear relationship between the initial rock temperature and the released heat of the surrounding rock. The radius of the heat-adjusting layer and the initial rock temperature presents a quadratic function relation. The lining concrete actually cures under the variable high-temperature environment and the real curing temperature decreases with time and becomes stable seven days later. The results would contribute to providing support for high geothermal tunnel research and design.

Section: The Change Rule Of Lining Concrete Temperaturementioning

confidence: 92%

A Study on the Heat Transfer of Surrounding Rock-Supporting Structures in High-Geothermal Tunnels

Liu

et al. 2020

Applied Sciences

“…The commonly used FRP materials for repairing and strengthening of reinforced concrete structures include carbon fiber‐reinforced polymer (CFRP), aramid fiber‐reinforced polymer (AFRP), basalt fiber‐reinforced polymers (BFRP), and glass fiber reinforced polymer (GFRP). CFRP has high specific strength and modulus, simple and convenient construction, minor impact on the original structure, and fatigue resistance 19–23 . So, CFRP has been widely used in the strengthening of reinforced concrete structures.…”

Section: Introductionmentioning

confidence: 99%

“…CFRP has high specific strength and modulus, simple and convenient construction, minor impact on the original structure, and fatigue resistance. [19][20][21][22][23] So, CFRP has been widely used in the strengthening of reinforced concrete structures. With more and more applications of CFRP systems, its durability is getting more and more attention.…”

mentioning

confidence: 99%

Effect of chloride penetration on CFRP sheet, CFRP‐concrete interface, and CFRP‐strengthened concrete beams

Han

et al. 2023

Structural Concrete

Whether the performance of carbon fiber‐reinforced polymer (CFRP)‐strengthened concrete structure is affected by chloride penetration is the key to the application under chloride environments. In this paper, the effect of chloride penetration on tensile properties of CFRP sheet, bond behavior of CFRP‐concrete, and flexural performance of CFRP‐strengthened concrete beams were studied. Results show that chloride penetration has no effect on the elastic modulus of the CFRP sheet. The tensile strength and elongation of the CFRP sheet decrease with the exposure time increase, reducing by 10% and 12.7% after 240 days. The interface failure of CFRP‐concrete is likely to occur on the concrete surface. As the exposure time increases, the interface failure develops toward the epoxy resin layer; the sliding stiffness and end slip of the interface decrease. However, the ultimate bearing capacity of the interface first increases and then decreases. As the exposure time increase, the effective bonding length gradually increases, and the failure mode of CFRP‐strengthened beams changes from bending failure to shear failure. After 120 days, the ultimate bearing capacity of the beams is significantly reduced. From three parts of materials, interfaces, and components to provide an evaluation basis for the use, regular detection, and life prediction of CFRP‐strengthened reinforced concrete beams under chloride environments.

Advances in Structural Engineering

“…Mohammed et al (2019) put forward a simplified new approach for designing RC specimens with circular section which converts circular section specimens to square section specimens with equivalent area, the test results showed that the RC specimens with circular section and its equivalent square specimens have similar nonlinear performance. The paper of Mousa et al (2019) evaluated the applicability of crack-control models, which were based on rectangular section, to RC bridge members with a circular section, and it was considered that the formula can be applied to circular section after redefining parameters. Same as RC structure, there are few design methods of SRC based on circular section.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on local bond-slip constitutive model between steel and steel fiber reinforced concrete structure of circular cross-section

Zheng

Zhou

et al. 2022

The interface slip between shape steel and concrete is one of the biggest problems in numerical simulation of composite structures, this paper aims to investigate interfacial bond-slip behavior between steel and steel fiber reinforced concrete. For this purpose, a series of push-out tests on 15 circular section specimens which were designed and fabricated with different steel fiber ratio, interface embedded length and concrete cover thickness have been done. Experimental results show that average bond strength versus free end slip curves of each specimen is similar, and then a basic average bond strength-free end slip constitutive model was proposed in this paper. Meanwhile, considering the distribution regularities of steel strains, local bond strength and relative slip along the interface embedded length at different load levels were obtained through the mechanical derivation, the results show that the maximum local bond strength was located near the free end, and the local bond strength away from free end tended to be steady. Based on the basic average bond strength-free end slip constitutive model, two position functions were proposed to describe the local bond-slip constitutive model considering the variation of positions. Two position functions are of great significance for further research on SSFRC non-linear properties by FEM.