scholarly journals Experimental Evaluation of PSC Structures from FRP with a Prestressing Strengthening Method

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1265
Author(s):  
Tae-Kyun Kim ◽  
Sang-Hyun Kim ◽  
Jong-Sup Park ◽  
Hee-Beom Park
Keyword(s):  
Prestressed Concrete ◽  
Strengthening Effect ◽  
Fiber Reinforced ◽  
Prestress Loss ◽  
Near Surface ◽  
Reinforced Plastics ◽  
Near Surface Mounted ◽  
Fiber Reinforced Plastics ◽  
Flexural Tests ◽  
Strengthening Method

A prestressed concrete (PSC) structure is subject to prestress losses in the long and short terms, and the structure ages over time. The structure is susceptible to corrosion from exposure to environmental factors such as moisture, chloride, and carbonation, thus causing prestress loss. Therefore, strengthening the structure is needed to address this problem. Here, the near surface mounted (NSM) method and the external prestressing (EP) method were selected because they are capable of applying additional prestressing. Further, we used fiber-reinforced plastics or polymers, or carbon fiber-reinforced plastics or polymers because of their high tensile strength and noncorrosive properties. For EP tests, prestressed strands were used. Accordingly, this study performs four-point flexural tests and evaluations for 12 types of specimens fabricated with different PSC methods. All specimens fabricated with the NSM (prestressing, no prestressing) and EP methods achieved stiffness that was 50–60% higher than that of the control PSC specimen. It was observed that the EP method in conjunction with prestressing yielded the best strengthening effect. It is expected that the results of this study will be applied to real structures for strengthening them and improving their performances.

Quasi-Plane-Hypothesis of Strain Coordination for RC Beam Strengthened with External-Bonded or Near-Surface Mounted Carbon Fiber Reinforced Plastic Strip

2011 ◽  
Vol 255-260 ◽  
pp. 54-58 ◽  
Author(s):  
Zhen Hua Ren ◽  
Xian Tao Zeng
Keyword(s):  
Weight Ratio ◽  
Neutral Axis ◽  
Reinforced Concrete Beams ◽  
Superior Performance ◽  
Rc Beam ◽  
Fiber Reinforced ◽  
Near Surface ◽  
Reinforced Plastics ◽  
Steel Rebar ◽  
Near Surface Mounted

Rehabilitation of existing structures with fiber reinforced plastics (FRP) has been growing in popularity because they offer superior performance in terms of resistance to corrosion and high stiffness-to-weight ratio. This paper presents strain coordination results of (two groups)15 reinforced concrete beams strengthened with different methods including external-bonded and near-surface mounted carbon FRP strip in order to investigate the strain coordination of CFRP and steel rebar of RC beam. Because there is relative slipping between RC beam and CFRP, the strain of CFRP and steel rebar of RC beam satisfies the quasi-plane-hypothesis, that is, the strain of longitudinal fiber that parallels to the neutral axis of plated beam within the scope of effective height (h0) of the cross section is in direct proportion to the distance from the fiber to the neutral axis, the strain of FRP and steel rebar satisfies the equation: , the value of is equal to 1.1~1.3 according to the test results.

Quasi-Plane-Hypothesis of Strain Coordination for RC Beam Strengthened with Near-Surface Mounted Carbon Fiber Reinforced Plastic Bar or Helical Rib Bar

2011 ◽  
Vol 243-249 ◽  
pp. 541-545 ◽  
Author(s):  
Xian Tao Zeng ◽  
Zhen Hua Ren
Keyword(s):  
Weight Ratio ◽  
Neutral Axis ◽  
Reinforced Concrete Beams ◽  
Superior Performance ◽  
Rc Beam ◽  
Fiber Reinforced ◽  
Near Surface ◽  
Reinforced Plastics ◽  
Steel Rebar ◽  
Near Surface Mounted

Rehabilitation of existing structures with fiber reinforced plastics (FRP) has been growing in popularity because they offer superior performance in terms of resistance to corrosion and high stiffness-to-weight ratio. This paper presents strain coordination results of (two groups)6 reinforced concrete beams strengthened with different methods including near-surface mounted CFRP bar and helical rib rebar in order to investigate the strain coordination of CFRP bar or HR bar and steel rebar of RC beam. Because there is relative slipping between RC beam and bar, the strain of CFRP or HR bar and steel rebar of RC beam satisfies the quasi-plane-hypothesis, that is, the strain of longitudinal fiber that parallels to the neutral axis of plated beam within the scope of effective height (h0) of the cross section is in direct proportion to the distance from the fiber to the neutral axis, the strain of CFRP or HR and steel rebar satisfies the equation:εCH=βεsteel , the value of β is equal to 1.0～1.2 according to the test results.

Effect of long climatic ageing on the microstructure of the surface of сarbon-fiber-reinforced plastics on base epoxy matrix

2019 ◽  
pp. 157-169 ◽  
Author(s):  
I. S. Deev ◽  
E. V. Kurshev ◽  
S. L. Lonsky
Keyword(s):  
Climatic Factors ◽  
Temperate Climate ◽  
Fiber Reinforced ◽  
Humid Climate ◽  
Climatic Zones ◽  
Reinforced Plastics ◽  
Carbon Plastics ◽  
Fiber Reinforced Plastics ◽  
Determining Factor

Studies and experimental data on the microstructure of the surface of samples of epoxy сarbon-fiber-reinforced plastics that have undergone long-term (up to 5 years) climatic aging in different climatic zones of Russia have been conducted: under conditions of the industrial zone of temperate climate (Moscow, MTsKI); temperate warm climate (Gelendzhik, GTsKI); a warm humid climate (Sochi, GNIP RAS). It is established that the determining factor for aging of carbon plastics is the duration of the complex effect of climatic factors: the longer the period of climatic aging, the more significant changes occur in the microstructure of the surface of the materials. The intensity of the aging process and the degree of microstructural changes in the surface of carbon plastics are affected by the features of the climatic zone. general regularities and features of the destruction of the surface of carbon plastics after a long-term exposure to climatic factors have been established on the basis of the analysis and systematization of the results of microstructural studies.

Sign in / Sign up

Export Citation Format

Share Document