Effect of Column Parameters on Cyclic Behavior of Ultra-High-Performance Concrete-Filled Fiber-Reinforced Polymer Tubes

2013 ◽  
Vol 110 (5) ◽  
2019 ◽  
Vol 11 (S1) ◽  
pp. 35-51
Author(s):  
Shahnaz Basim ◽  
Farzad Hejazi ◽  
Raizal Saifulnaz Bin Muhammad Rashid

AbstractBeam–column joints play an important role in providing lateral stiffness and integrity of frames during dynamic loading such as earthquake. In the high humidity areas, during functioning of the building cracks occur, which leads to the corrosion of the reinforcement due to the environmental exposures. Therefore, one of the main failures mechanism of building during an earthquake is caused by easily yielding of corroded steel reinforcement, which leads to reduce functionality of the frame joints in transferring the loads. This study proposed a new design to reinforce the beam-column joints with embedded carbon fiber-reinforced polymer (CFRP) rods, due to their extremely high strength and stiffness, along with the fact that they will not rust or corrode and very light weight. CFRP rods are used in reinforced concrete (RC) frame and ultra-high-performance concrete (UHPC) frame subjected to dynamic load. The prototype of the proposed design is constructed as frame with conventional concrete and frame with UHPC material to conduct experiments Test as well as numerical analysis to evaluate the performance of the proposed joints under dynamic loads. The results showed improvement in the performance of the frames reinforced with embedded CFRP in joints in terms of lateral load resistance capacity, ductility behaviour, overall stiffness, and failure mechanism.


Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 125
Author(s):  
Junjie Zeng ◽  
Tianwei Long

In this study, a novel form of tubular columns that is made of ultra-high-performance concrete (UHPC) internally reinforced with fiber-reinforced polymer (FRP) grid (herein referred to as FRP grid-UHPCtubular column) was developed. The axial compression test results of FRP grid-UHPC tubular columns with and without in-filled concrete are presented and discussed. Effects of the number of the FRP grid-reinforcing cages, the presence of in-filled concrete, and the presence of external FRP confinement were investigated. The test results confirmed that the FRP-UHPC tubular columns have a satisfactory compressive strength, and the strength and ductility of FRP-confined concrete-filled FRP grid-UHPC tube columns are enhanced due to the confinement from the FRP wrap. The proposed FRP grid-reinforced UHPC composite tubes are attractive in structural applications as pipelines or permanent formworks for columns, as well as external jackets (can be prefabricated in the form of two halves of tubes) for strengthening deteriorated reinforced concrete columns.


2021 ◽  
pp. 136943322110623
Author(s):  
Rui Hu ◽  
Zhi Fang ◽  
Ruinian Jiang ◽  
Yu Xiang ◽  
Chuanle Liu

In the present paper, a comprehensive study on the flexural fatigue behavior of ultra-high-performance concrete (UHPC) beams prestressed with carbon-fiber-reinforced polymer (CFRP) tendons is reported. A total of two UHPC beams prestressed with CFRP tendons were experimentally investigated. On the basis of the fatigue constitutive model of the materials, a fatigue prediction model (FPM) was developed to simulate the flexural fatigue evolvement of the beams. The strain and stress in UHPC and CFRP tendons were calculated by the sectional stress analysis. The influence of steel fiber was considered in the formulae for the crack resistance and crack width, and the midspan deflection was calculated using the sum of deflection before cracking and increment after cracking. The obtained test results were used to verify the FPM. A parametric study was then conducted to analyze the fatigue development of such component, and a formula to predict the flexural fatigue life of UHPC beams under different fatigue loads was proposed.


2019 ◽  
Vol 23 (4) ◽  
pp. 713-732 ◽  
Author(s):  
Shu Fang ◽  
Li-Juan Li ◽  
Tao Jiang ◽  
Bing Fu

Concrete infilled in a small-diameter fiber-reinforced polymer tube is strongly confined, thus having a high compressive strength and excellent deformability. Such a feature is exploited in the development of two types of high-performance hybrid members at Guangdong University of Technology, China, by incorporating small-diameter (30 to 60 mm) concrete-filled fiber-reinforced polymer tubes as internal reinforcements. Understanding the compressive behavior of small-diameter concrete-filled fiber-reinforced polymer tubes is essential to understanding the behavior of the proposed hybrid members and the development of their design approaches. This article therefore presents a systematic study on the axial compressive behavior of small-diameter concrete-filled fiber-reinforced polymer tubes with the test parameters being the thickness, diameter, and fiber type of fiber-reinforced polymer tubes and concrete strength. The test results show that the tested small-diameter concrete-filled fiber-reinforced polymer tubes have a compressive strength and an ultimate axial strain of up to 267 MPa and 10.3%, which are, respectively, about 6 and 34 times that of the corresponding unconfined specimens, demonstrating the great potential of small-diameter concrete-filled fiber-reinforced polymer tubes as internal reinforcements for use in high-performance hybrid members. The applicability of three widely accepted stress–strain models developed based on test results of fiber-reinforced polymer-confined concrete cylinders with a diameter of 150 mm or above is also examined. It is shown that the three models tend to predict a steeper second portion of stress–strain responses than the test results, revealing the need of a tailored stress–strain model for small-diameter concrete-filled fiber-reinforced polymer tubes.


Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3077
Author(s):  
Xiaoqing Xu ◽  
Zhujian Hou

The application of fiber-reinforced polymer (FRP) bars and ultra-high performance concrete (UHPC) in the field of civil engineering is promising. An innovative FRP bar-reinforced UHPC short-ribbed bridge deck slab, with low self-weight and high structural performance, was proposed in this study. The behavior of one-way basalt FRP (BFRP) bar-reinforced UHPC slabs under concentrated load was experimentally investigated, and compared with that of a steel bar-reinforced UHPC slab. The ultimate capacity of the one-way BFRP bar-reinforced UHPC slab was 0.59 times that of the steel bar-reinforced UHPC slab, while its ductility was better. Increasing the reinforcement ratio and loading area was beneficial to the ductility of one-way BFRP bar-reinforced UHPC slabs. Moreover, the model proposed by EI-Gamal et al. was found to be suitable for evaluating the punching shear capacities of one-way BFRP bar-reinforced UHPC slabs. However, the model failed to consider the unique strain-hardening characteristics of UHPC, which led to conservative prediction.


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