Aspects of behaviour of CFRP reinforced concrete beams in bending
صفحه اصلی: http://cfrp.blogfa.com/post-8.aspx
Abstract

The corrosion of steel poses a serious problem to the durability of reinforced concrete structures and fibre reinforced polymer (FRP) has emerged as a potential alternative material to the traditional steel. The results of a test series consisting of carbon FRP (CFRP) and steel bars reinforced concrete beams are reported in this paper. The results indicated that the behaviour of CFRP and steel reinforced beams was similar in many aspects. Both type of beams failed in their predicted modes of failure. The strength design method underestimated nominal moment capacity of CFRP reinforced beams. The deflection of CFRP reinforced beams was satisfactory at service load level, corresponding to theoretical load capacity. The deformability factor of CFRP reinforced beams was more than 6 indicating their ductile nature of failure.

Keywords: Fibre reinforced polymer; Carbon FRP; Mode of failure; Concrete beams; Reinforcement; Moment; Deflection; Deformability



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http://www.4shared.com/file/15800179/14646b75/Aspects_of_behaviour_of_CFRP_reinforced_concrete_beams_in_bending.html

http://cfrp.blogfa.com/post-8.aspx
Nonlinear finite element analysis of reinforced concrete beams strengthened

by fiber-reinforced plastics

Hsuan-Teh Hu *, Fu-Ming Lin, Yih-Yuan Jan

Department of Civil Engineering, National Cheng Kung University, Tainan 701, Taiwan

Abstract

Numerical analyses are performed using the ABAQUS finite element program to predict the ultimate loading capacity of

rectangular reinforced concrete beams strengthened by fiber-reinforced plastics applied at the bottom or on both sides of

these beams. Nonlinear material behavior, as it relates to steel reinforcing bars, plain concrete, and fiber-reinforced plastics is

simulated using appropriate constitutive models. The influences of fiber orientation, beam length and reinforcement ratios on

the ultimate strength of the beams are investigated. It has been shown that the use of fiber-reinforced plastics can

significantly increase the stiffnesses as well as the ultimate strengths of reinforced concrete beams. In addition, with the same

fiber-reinforced plastics layer numbers, the ultimate strengths of beams strengthened by fiber-reinforced plastics at the

bottom of the beams are much higher than those strengthened by fiber-reinforced plastics on both sides of the beams.

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http://www.4shared.com/file/15798617/993b0f3a/Nonlinear_finite_element_analysis_of_rc_beams_strengthened_by_frp.html

http://cfrp.blogfa.com/post-10.aspx
Flexural behaviour of reinforced concrete beams strengthened by CFRP sheets

M.R. Esfahania, M.R. Kianoushb,, A.R. Tajaria

a Department of Civil Engineering, Ferdowsi University of Mashhad, Iran

b Department of Civil Engineering, Ryerson University, Toronto, Ontario, Canada

Abstract

This paper investigates the flexural behaviour of reinforced concrete beams strengthened using Carbon Fibre Reinforced Polymers (CFRP) sheets. The effect of reinforcing bar ratio on the flexural strength of the strengthened beams is examined. Twelve concrete beam specimens with dimensions of 150 mm width, 200 mm height, and 2000 mm length were manufactured and tested. Beam sections with three different reinforcing ratios, were used as longitudinal tensile reinforcement in specimens. Nine specimens were strengthened in flexure by CFRP sheets. The other three specimens were considered as control specimens. The width, length and number of layers of CFRP sheets varied in different specimens. The flexural strength and stiffness of the strengthened beams increased compared to the control specimens. From the results of this study, it is concluded that the design guidelines of ACI 440.2R-02 and ISIS Canada overestimate the effect of CFRP sheets in increasing the flexural strength of beams with small reinforcing bar ratio ‌values compared to the maximum value, max, specified in these two guidelines.With the increase in the reinforcing bar ratio value in beams, the ratios of test load to the load calculated using ACI 440 and ISIS Canada increased. Therefore, the equations proposed by the two design guidelines are more appropriate for beams with large reinforcing bar ratio values. In the strengthened specimens with the large reinforcing bar ratio, close to the maximum code value of reinforcing bar ratio max, failure occurred with adequate ductility.

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http://www.4shared.com/file/15801230/b32ecfe9/Flexural_behaviour_of_reinforced_concrete_beams_strengthened_by.html

http://cfrp.blogfa.com/post-9.aspx
FLEXURAL BEHAVIOR OF REINFORCED AND PRESTRESSED CONCRETE BEAMS

USING FINITE ELEMENT ANALYSIS

by: Anthony J. Wolanski, B.S

A Thesis submitted to the Faculty of the Graduate School, Marquette University, in Partial Fulfillment of the Requirements for the Degree of Master of Science

Milwaukee, Wisconsin

May, 2004

PREFACE

Several methods have been utilized to study the response of concrete structural components. Experimental based testing has been widely used as a means to analyze individual elements and the effects of concrete strength under loading. The use of finite element analysis to study these components has also been used. This thesis is a study of reinforced and prestressed concrete beams using finite element analysis to understand their load-deflection response. A reinforced concrete beam model is studied and compared to experimental data. The parameters for the reinforced concrete model were then used to model a prestressed concrete beam. Characteristic points on the load-deformation response curve predicted using finite element analysis were compared to theoretical (hand-calculated) results. Conclusions were then made as to the accuracy of using finite element modeling for analysis of concrete. The results compared well to experimental and hand calculated.

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http://www.4shared.com/file/15799907/33c01e23/ANSYS_MODELING_OF_FLEXURAL_BEHAVIOR_OF_RC_BEAM_STRENGTHENING_BY_FRP.html

http://cfrp.blogfa.com/post-13.aspx
Debonding- and Fatigue-Related Strain Limits

for Externally Bonded FRP

Kent A. Harries

Assistant Professor, Dept. of Civil and Environmental Engineering, Univ. of Pittsburgh, Pittsburgh, PA 15261

John Aidoo

Assistant Professor, Dept. of Civil and Environmental Engineering, Rose-Hulman Institute of Technology,



Abstract: Available guidance for mitigating debonding failure of externally bonded fiber

reinforced polymer
FRP composites applied to concrete is evaluated based on data obtained

from large- and full-scale experimental programs. Current recommendations are inadequate to

effectively mitigate intermediate crack-induced debonding in flexural members. An improved,

although still simple to apply, equation for determining limiting FRP material properties to

mitigate debonding is presented and evaluated. Additionally, the effect of fatigue loading on the

debonding behavior of externally bonded FRP is not adequately addressed in practice. In the

limited data presented, a degradation of bond behavior is observed even under fatigue loading

conditions amounting to an FRP stress range of no more than 4% of the FRP capacity.

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http://www.4shared.com/file/15803900/3e5fbb40/good_paper.html

http://cfrp.blogfa.com/post-14.aspx
DETERMINATION OF ULTIMATE FLEXTURAL CAPACITY OF

STRENGTHENED BEAMS WITH STEEL PLATES AND GFRP



Javad VASEGHI AMIRI

Assistant Professor in Mazandaran University, Iran, Email : Vaseghi@ tech.umz.ac.ir

Morteza HOSSEINALIBEGIE

Assistant Professor in Mazandaran University, Iran, Email : Baygie@ tech.umz.ac.ir

SUMMARY

In order to investigate the effect of strengthening of reinforced beams using steel and GFRP plates on the flexural strength and ductility ,14 specimens have been designed and tested .The specimen regarding the amount of compressive steel and the condition of strengthening are divided in to two Group I and II .All the beams were simply supported and were tested under two-point loading. The amount of imposed load, strain in concrete, strain in the level of tension reinforcement bars and deflection of mid span in different stages of loading have been measured and recorded . According to test results the amount of change in the flexural strength and ductility of beams have been calculated. The effect of shape and type of the performance ,the strengthening of beams on the flexural parameters and ductility have been investigated.

Keyword: Strengthening, GFRP, Flexural behavior

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http://www.4shared.com/file/15829633/925a4d00/DETERMINATION_OF_ULTIMATE_FLEXTURAL_CAPACITY.html

http://cfrp.blogfa.com/post-15.aspx
بررسی عملکرد خمشی تيرهاي بتن مسلح

FRP مقاوم سازی شده با ورقهاي

علي اكبر مقصودي، استاديار، دانشكده فني دانشگاه شهيد باهنركرمان

رضا رهگذر، استاديار، دانشكده فني دانشگاه شهيد باهنركرمان

سيد حميد هاشمي، دانشجوي دكتري سازه دانشگاه شهيد باهنركرمان

hamidhashemi55@yahoo.com

چكيده :

FRP در اين تحقيق اثر ورقها ي در مقاوم ساز ي خمش ي تيرها ي بتن مسلح حاو ي بتن با مقاومت بالا مورد بررس ي قرار گرفته است . تعداد شش تير بتن ي دارا ي سطح مقطع، طول و ميزان ميلگرد فشار ي و برشی يکسان حاو ي بتن با مقاومت بالا، ساخته شده و پس از مقاوم سازی تحت آزمايش خمش چهار نقطه ا ي قرار گرفته و مورد بررسی قرار گرفته اند . از شش نمونه ذکر شده يک نمونه به عنوان نمونه شاهد و دو نمونه ديگر با يک و چهار لايه FRP از مقاوم سازي شده اند. جهت بررسي دقيق رفتار ا ين تيرها تعداد قابل توجهي کرنش سنج رو ي ميلگردهاي کششي، فشار ي و همچنين سطح بتن و FRP نصب شده که نتايج حاصله در زمينه مقاومت نهايي، شکل پذيري و الگوی گسترش ترک آنها در ا ين تحقيق ارائه شده است .

نتايج آزمايشات نشان دهنده عملکرد مناسب مقاوم سازی توسط الیاف پلیمری در افزايش مقاومت نهايي، کاهش شديد عرض ترک، کاهش خيز و بطور کلی بهبود شرايط در حالت بهره برداری و نهايی بوده و ضعف عمده آنها به علت رفتار خطی تا لحظه شکست، در کاهش شکل پذيری مقطع می باشد.

شکل پذيری. ، FRP ، كلمات كليدي: تير بتن مسلح، بتن مقاومت بالا، مقاوم سازي

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http://www.4shared.com/file/15829984/e4964655/FINAL_PAPER.html

http://cfrp.blogfa.com/post-16.aspx
Guide for the Design and Construction of

Externally Bonded FRP Systems for

Strengthening Concrete Structures

ACI 440.2R-02

Fiber-reinforced polymer (FRP) systems for strengthening concrete structures have emerged as an alternative to traditional strengthening techniques, such as steel plate bonding, section enlargement, and external post-tensioning. FRP strengthening systems use FRP composite materials as supplemental externally bonded reinforcement. FRP systems offer advantages over traditional strengthening techniques: they are lightweight, relatively easy to install, and are noncorrosive. Due to the characteristics of FRP materials, the behavior of FRP strengthened members, and various issues regarding the use ofexternally bonded reinforcement, specific guidance on the use of these systems is needed. This document offers general information on the history and use of FRP strengthening systems; a description of the unique material properties of FRP; and committee recommendations on the engineering, construction, and inspection of FRP systems used to strengthen concrete structures. The proposed guidelines are based on the knowledge gained from worldwide experimental research, analytical work, and field applications of FRP systems used to strengthen concrete structures.

Keywords: aramid fibers; bridges; buildings; carbon fibers; concrete; corrosion; crack widths; cracking; cyclic loading; deflections; development length; earthquake-resistant; fatigue; fiber-reinforced polymers; flexure; glass fiber; shear; stresses; structural analysis; structural design; time-dependent; torsion.

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