Influence of Concrete Strength on Confinement Effectiveness of Fiber-Reinforced Polymer Circular Jackets

2005 ◽  
Vol 102 (3) ◽  
Keyword(s):  
Concrete Strength ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer

Empirical Formulae To Predict Pressure And Impulsive Asymptotes For P–I Diagrams Of RC Columns Strengthened With FRP

2011 ◽  
Author(s):  
A. A. Mutalib ◽  
Norhisham Bakhary
Keyword(s):  
Concrete Strength ◽  
Numerical Results ◽  
Fiber Reinforced Polymer ◽  
Blast Loads ◽  
Fiber Reinforced ◽  
Rc Columns ◽  
Pressure Impulse ◽  
Reinforced Polymer ◽  
Blast Response ◽  
Parametric Studies

Kajian terhadap keupayaan struktur dalam menahan beban letupan menggunakan Fiber Reinforced Polymer (FRP) adalah sangat terhad. Dalam kajian ini, satu analisis terhadap keupayaan FRP bagi menahan beban letupan dilakukan. Tujuan analisis ini adalah untuk memperolehi hubungan antara kekuatan FRP, bilangan lapisan ketebalan FRP dan susunatur FRP bagi menahan kekuatan sesuatu beban letupan. Kajian ini dilakukan mengunakan model tiang diperkukuh dengan FRP yang dibina menggunakan perisian LS–DYNA. Ia melibatkan beberapa siri simulasi untuk meramalkan tindakbalas letupan dan kerosakkan pada tiang sekiranya sesuatu beban letupan dikenakan. Melalui simulasi ini, kekuatan FRP, bilangan lapisan ketebalan FRP dan susunatur FRP dapat ditentukan. melalui keputusan–keputusan yang diperolehi, pressure–impulse diagram (P–I) bagi tiang yang diperkukuhkan dengan FRP dapat dibentuk. Kata kunci: Pengukuhan; beban letupan; FRP; P–I diagrams There are only limited studies that directly correlate the increase in structural capacities in resisting the blast loads with the fiber reinforced polymer (FRP) strengthenin. In this paper, numerical analyses of dynamic response and damage of reinforced concrete (RC) columns strengthened with FRP to blast loads are carried out using the commercial software LS–DYNA. A series of simulations are performed to predict the blast response and damage of columns with different FRP type. The simulations also involved parametric studies by varying the FRP thickness, configuration, different column dimension, concrete strength, and longitudinal and transverse reinforcement ratio. The numerical results are used to develop pressure–impulse (P–I) diagrams of FRP strengthened RC columns. Based on the numerical results, the empirical formulae are derived to calculate the pressure and impulse asymptotes of the P–I diagrams of RC columns strengthened with FRP. Key words: Strengthening; blast loads; FRP; P–I diagrams

scholarly journals NGHIÊN CỨU THIẾT KẾ TĂNG CƯỜNG KHẢ NĂNG CHỊU UỐN SÀN BÊ TÔNG CỐT THÉP BẰNG VẬT LIỆU TẤM SỢI FRP DÁN NGOÀI

2021 ◽  
Vol 5 (1) ◽  
pp. 2330-2341
Author(s):  
Nguyễn Thị Thanh ◽  
Phạm Việt Hùng ◽  
Ngô Quý Tuấn ◽  
Lê Minh Đức ◽  
Nguyễn Trường Giang
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Concrete Strength ◽  
Fiber Reinforced Polymer ◽  
Concrete Slabs ◽  
Fiber Reinforced ◽  
Flexural Strengthening ◽  
Reinforced Concrete Slabs ◽  
Reinforced Polymer ◽  
Calculation Results

Phương pháp tăng cường khả năng chịu uốn của kết cấu sàn bê tông cốt thép sử dụng vật liệu tấm sợi FRP (Fiber Reinforced Polymer) dán ngoài đã trở nên phổ biến, vì những ưu điểm của chúng mang lại như cường độ chịu kéo cao, trọng lượng nhẹ, cách điện, cách nhiệt tốt, bền theo thời gian. Bài báo trình bày quy trình thiết kế tăng cường khả năng chịu uốn của sàn bê tông cốt thép gia cường bằng tấm sợi FRP dán ngoài để đảm bảo yêu cầu khai thác và khảo sát hiệu quả tăng cường tương ứng với các cấp cường độ chịu nén của bê tông theo hướng dẫn ACI 440.2R-17. Kết quả tính toán theo trình tự đề nghị giúp chọn và kiểm tra được diện tích tấm FRP tăng cường cần thiết. Ngoài ra, kết quả tính toán chỉ ra rằng mức độ tăng cường khả năng chịu uốn của sàn tỷ lệ thuận với cường độ chịu nén của bê tông, tương ứng với cường độ bê tông tăng từ 11,5 MPa đến 19,5 MPa, sức kháng uốn tính toán tăng từ 91%  đến 144%. Đồng thời, kết quả cũng cho thấy rằng sự phá hoại của sàn bê tông cốt thép xảy ra do mất dính bám giữa lớp FRP gia cường khỏi bề mặt cấu kiện là chủ yếu. ABSTRACT The method of the flexural strengthening of reinforced concrete slabs using the externally bonded FRP (fiber reinforced polymer) laminates has become popular because of their advantages as high tensile strength, large modulus of elasticity, lightweight, high abrasion resistance, electrical insulation, good heat resistance and durable over the time. The paper presented the design procedure for the flexural strengthening of reinforced concrete slabs with FRP laminates to ensure the mining requirements and investigation of the reinforcement efficiency corresponding to the compressive strength levels of concrete based on ACI 440.2R-17. Calculation results in the suggested sequence helped select and check the required reinforcement FRP areas. In addition, the calculation results showed that the degree of increased flexural strengthening of the slabs was proportional to the compressive strength of the concrete, corresponding to the concrete strength increased from 11,5 MPa to 19,5 MPa, flexural strengthening increases from 91% to 144%. Moreover, the damage to the reinforced concrete slabs was caused by the debonding between the FRP and the surface of the structures.

scholarly journals Bond-Slip Behavior of Basalt Fiber Reinforced Polymer Bar in Concrete Subjected to Simulated Marine Environment: Effects of BFRP Bar Size, Corrosion Age, and Concrete Strength

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Yongmin Yang ◽  
Zhaoheng Li ◽  
Tongsheng Zhang ◽  
Jiangxiong Wei ◽  
Qijun Yu
Keyword(s):  
Marine Environment ◽  
Concrete Strength ◽  
Concrete Structures ◽  
Basalt Fiber ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Bond Slip ◽  
Reinforced Polymer ◽  
Superior Corrosion Resistance ◽  
Basalt Fiber Reinforced Polymer

Basalt Fiber Reinforced Polymer (BFRP) bars have bright potential application in concrete structures subjected to marine environment due to their superior corrosion resistance. Available literatures mainly focused on the mechanical properties of BFRP concrete structures, while the bond-slip behavior of BFRP bars, which is a key factor influencing the safety and service life of ocean concrete structures, has not been clarified yet. In this paper, effects of BFRP bars size, corrosion age, and concrete strength on the bond-slip behavior of BFRP bars in concrete cured in artificial seawater were investigated, and then an improved Bertero, Popov, and Eligehausen (BPE) model was employed to describe the bond-slip behavior of BFRP bars in concrete. The results indicated that the maximum bond stress and corresponding slip decreased gradually with the increase of corrosion age and size of BFRP bars, and ultimate slip also decreased sharply. The ascending segment of bond-slip curve tends to be more rigid and the descending segment tends to be softer after corrosion. A horizontal end in bond-slip curve indicates that the friction between BFRP bars and concrete decreased sharply.

scholarly journals Improving the Adhesion of BFRP Strips to the Concrete Surface

2019 ◽  
Vol 2 (2) ◽  
pp. 220-228
Author(s):  
Hasan Hüseyin Akbalık ◽  
Ali Sarıbıyık
Keyword(s):  
Concrete Strength ◽  
Basalt Fiber ◽  
Concrete Surface ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Frp Composites ◽  
Adhesion Ability ◽  
Four Point Bending ◽  
Frp Composite ◽  
Reinforced Polymer

Fiber Reinforced Polymer (FRP) composites are widely used in repair and strengthening of reinforced concrete structural elements. The FRP composite adhered to the concrete surface may be separated from the concrete surface in the form of debonding before reaching the ultimate strength. Epoxy resin, concrete strength, fiber properties and application method have an important role in bonding of FRP composites to concrete surfaces. In this study, concrete beam specimens were produced in order to investigate the adhesion of Basalt Fiber Reinforced Polymer (BFRP) composites to the concrete surface using conventional concretes. Stress distribution between concrete and BFRP was investigated by opening a gap in the bottom center of the samples. Unidirectional basalt fiber fabric was used in the production of the test specimens. The effects of concrete surface properties and U winding method on the end of fiber adhesion ability were investigated by bonding BFRP composite to the lower surfaces of the Specimens. Specimens were tested by four point bending experiment. According to the results obtained, the grinding of the concrete surface and the U-winding method significantly improve the adhesion.”

scholarly journals Experimental Study on Mechanical Properties of Interface between Basalt Fiber-Reinforced Polymer/Glass Fiber-Reinforced Polymer Composite Cement Plate and Concrete

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Lifeng Zhang ◽  
Hui Liu ◽  
Wenqiang Li ◽  
Hangjun Liu ◽  
Xuehui An ◽  
...  
Keyword(s):  
Shear Strength ◽  
Failure Modes ◽  
Shear Failure ◽  
Concrete Strength ◽  
Concrete Block ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Bond Slip ◽  
Reinforced Polymer ◽  
Composite Samples

The bonding behaviors of the plate-concrete interface of a composite structure consisting of a concrete block in the middle and two cement plates at both sides play a key role in its overall mechanical performance. In this paper, the authors conduct 3 groups of push-out shear tests on a total of 39 composite samples to assess the bonding performance. The influence of the FRP cement plates, the concrete strength, and the ribs installed in the cement plate on the interfacial shear strength, the relative bond-slip, strain, and the failure modes of the composite samples is recorded and analyzed. The results show that (1) the shear strength and bond-slip performance of the interface are largely improved if the GFRP/BRRP cement plates are used; (2) shear strength of the interface increases with the concrete strength, while the deformation behaviors show no significant improvement; (3) an inclusion of the ribs to the interface enhances the shear strength and shear stiffness but decreases the maximum relative slip at failure; (4) most of the samples present the shear failures along the interface; however, the bending shear failure prior to the interface shear failure is also observed on the concrete block for low concrete strength samples and the samples with ribs; and (5) regression method is used to develop a constitutive model of the stress-slip at the interface to describe the relationship between the shear strength with the cement plates, the concrete strength, and ribs.

EFFECT OF SUBSTRATE PREPARATION ON THE LOAD-BEARING BEHAVIOR OF CFRP-CONFINED RC COLUMNS

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Klaus Holschemacher ◽  
Dennis Messerer ◽  
Stefan Kaeseberg
Keyword(s):  
Concrete Strength ◽  
Fiber Reinforced Polymer ◽  
Confined Concrete ◽  
Fiber Reinforced ◽  
Substrate Preparation ◽  
Rc Columns ◽  
Effective Measure ◽  
Load Bearing ◽  
Reinforced Polymer ◽  
Bearing Behavior

The confinement of reinforced concrete (RC) columns with fiber reinforced polymer (FRP) jackets is an effective measure for the strengthening and retrofitting of existing structures. The jacket withstands the increasing lateral strains of the axially loaded column causing a three-dimensional stress state inside the concrete. In the result, a higher concrete compressive strength can be achieved. So far, extensive international research on FRP-confined concrete has been conducted, but there are still some open issues regarding the influence of different parameters on the load-bearing behavior. This paper is focusing on the effect of the substrate preparation on the maximum concrete strength and stress-strain behavior. Therefore, an experimental study of carbon fiber reinforced polymer (CFRP) confined concrete cylinders with various substrate conditions and preparation methods is presented. The results are compared with previous investigations and assessed accordingly. Furthermore, recommendations regarding the substrate preparation by current national codes and guidelines are specified and considered critically.

scholarly journals Fatigue Behavior of Concrete Beam with Prestressed Near-Surface Mounted CFRP Reinforcement According to the Strength and Developed Length

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 51 ◽  
Author(s):  
Hee Park ◽  
Jong-Sup Park ◽  
Jae-Yoon Kang ◽  
Woo-Tai Jung
Keyword(s):  
Fatigue Behavior ◽  
Concrete Strength ◽  
Fatigue Loading ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Near Surface ◽  
Reinforced Polymer ◽  
Anchoring System ◽  
Near Surface Mounted

The prestressed near-surface mounted reinforcement (NSMR) using Fiber Reinforced Polymer (FRP) was developed to improve the load bearing capacity of ageing or degraded concrete structures. The NSMR using FRP was the subject of numerous studies of which a mere portion was dedicated to the long-term behavior under fatigue loading. Accordingly, the present study intends to examine the fatigue performance of the NSMR applying the anchoring system developed by Korea Institute of Construction and Building Technology (KICT). To that goal, fatigue test is performed on 6.4 m reinforced concrete beams fabricated with various concrete strengths and developed lengths of the Carbon Fiber Reinforced Polymer (CFRP) tendon. The test results reveal that the difference in the concrete strength and in the developed length of the CFRP tendon has insignificant effect on the strengthening performance. It is concluded that the accumulation of fatigue loading, the concrete strength and the developed length of the tendon will not affect significantly the strengthening performance given that sufficient strengthening is secured.

scholarly journals Strengthening Prestressed Concrete Bridge Girders and Building Beams with Carbon Fiber Reinforced Polymer Sheets

2021 ◽  
Vol 6 (1) ◽  
pp. 55-57
Author(s):  
Herish A. Hussein ◽  
Zia Razzaq
Keyword(s):  
Carbon Fiber ◽  
Flexural Strength ◽  
Cross Sections ◽  
Prestressed Concrete ◽  
Concrete Strength ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

The effect of Carbon Fiber Reinforced Polymer (CFRP) retrofitting and concrete type on the flexural strength of prestressed concrete I-section girders used in bridges and beams in buildings is investigated. Non-linear moment-curvature relationships are predicted using an iterative algorithm for both non-retrofitted and CFRP-retrofitted prestressed concrete girder and beam cross-sections with various concrete types. Two different CFRP-retrofitting schemes are analyzed for comparing their effectiveness. It is found that although non-retrofitted beam section exhibits greater ductility, the use of CFRP retrofitting in both tension and compression regions simultaneously results in a significant increase in flexural strength. It is also found that the higher the ultimate concrete strength, the higher is the influence of CFRP-retrofitting on increasing flexural strength.

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