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

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.

Envelope Response of Corroded RC Circular Columns Strengthened with Hybrid Fiber Reinforced Polymers

2011 ◽  
Vol 255-260 ◽  
pp. 3124-3128
Author(s):  
Jian Hui Li ◽  
Ying Li ◽  
Zong Cai Deng
Keyword(s):  
Seismic Energy ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Envelope Curve ◽  
Rc Columns ◽  
Reinforced Polymers ◽  
Reinforced Polymer ◽  
Frp Wrapping

Corroded RC columns do not possess necessary ductility to dissipate seismic energy during a major earthquake, the study investigates the use of hybrid fiber reinforced polymer (FRP) wrapping as a method of retrofitting non-ductile corroded RC columns, and a model to determine the envelope response of RC corroded columns strengthened with hybrid FRP are presented based on cross-section analysis for undamaged RC element. The results show that the technique of strengthening corroded RC column with hybrid FRP is quite effective, the envelope curve estimated using the linear plane assumption with modification by reinforcement slip model, may still be used as the envelope curve of RC corroded columns strengthened with hybrid FRP, a good agreement between analytical and experimental results is observed.

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 Seismic Behavior of Substandard RC Columns Retrofitted with Embedded Aramid Fiber Reinforced Polymer (AFRP) Reinforcement

Polymers ◽  
2015 ◽  
Vol 7 (12) ◽  
pp. 2535-2557 ◽  
Author(s):  
Engin Seyhan ◽  
Caglar Goksu ◽  
Ahmet Uzunhasanoglu ◽  
Alper Ilki
Keyword(s):  
Seismic Behavior ◽  
Aramid Fiber ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Rc Columns ◽  
Reinforced Polymer

scholarly journals Evaluation of Seismic Behaviors of Partially Deteriorated Reinforced Concrete Circular Columns Retrofitted with CFRP

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Dongxu Hou ◽  
Jianyun Pan ◽  
Xinglang Fan ◽  
Zhimin Wu ◽  
Prosper Marindiko
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Strength ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Element Analysis ◽  
Rc Columns ◽  
Reinforced Polymer ◽  
Seismic Behaviors ◽  
Failure Location

Deficiency of the concrete strength in some regions of reinforced concrete (RC) columns in practice may weaken the seismic behaviors of columns. Its effects on RC columns should be well understood. This paper aims to investigate the influences of deteriorated segment on the seismic behaviors of partially deteriorated RC columns and attempts to recover the seismic behaviors of partially deteriorated columns with Carbon Fiber Reinforced Polymer (CFRP) composites. A finite element analysis was carried out to simulate the seismic behaviors of CFRP-confined partially deteriorated RC columns. The numerical results were verified by the laboratory tests of six specimens. Based on the finite element results, the failure location of partially deteriorated columns in an earthquake was predicted, and the effectiveness of CFRP retrofitted on partially deteriorated columns was evaluated.

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.

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