Failure Modes of CFRP Flexural Strengthened Steel I-Beams

2011 ◽  
Vol 471-472 ◽  
pp. 590-595 ◽  
Author(s):  
Kambiz Narmashiri ◽  
Mohd Zamin Jumaat ◽  
Nor Hafizah Ramli Sulong
Keyword(s):  
Failure Modes ◽  
Steel Structures ◽  
Fiber Reinforced Polymer ◽  
Bending Test ◽  
Steel Beams ◽  
Numerical Studies ◽  
Reinforced Polymer ◽  
Cfrp Plate ◽  
Critical Regions ◽  
Incremental Loading

This paper presents the experimental and numerical studies on the flexural strengthened steel I-beams by using Carbon Fiber Reinforced Polymer (CFRP) strips. Nowadays, strengthening existing steel structures by using CFRP has been widely interested. One of the common usages of CFRP to strengthen steel beams is the flexural upgrading. In this case, CFRP strips are pasted on the tensile flange to improve flexural behaviors. The problems that are frequently reported for CFRP strengthened steel beams are the debonding, delaminating (peeling), and splitting. Identification these failure modes are essential to provide an appropriate level of safety for strengthened steel beams. To investigate the CFRP failure modes, four strengthened steel I-beams were chosen. The CFRP plates with different thicknesses in single and double (splice) layers were used. Both experimental test (four-points bending test) and numerical simulation (full 3D simulation with ANSYS) were employed. The incremental loading was applied until failure while deformations in the critical regions were recorded. The results reveal that for the CFRP flexural strengthened steel beams the following failure modes occurred: (a) debonding at the CFRP plate tips, (b) debonding below point loads, (c) delaminating at the ends of CFRP plate, and (d) splitting below point loads. The sequence of failure modes depended on the specifications of CFRP plate. Some recommendations are provided to overcome/retard these failures.

DESIGN OF ADEHSIVE JOINTS IN FRP-BONDED STEEL BEAMS

2012 ◽  
Vol 12 (01) ◽  
pp. 53-73
Author(s):  
REZA HAGHANI ◽  
MOHAMMAD AL-EMRANI ◽  
ROBERT KLIGER
Keyword(s):  
Steel Structures ◽  
Adhesive Joints ◽  
Design Model ◽  
Fiber Reinforced Polymer ◽  
Steel Beams ◽  
Fiber Reinforced ◽  
Design Models ◽  
Static Tests ◽  
Cfrp Laminates ◽  
Reinforced Polymer

The use of bonded carbon fiber-reinforced polymer (CFRP) laminates to strengthen and upgrade existing structures has attracted a great deal of attention during the past two decades. Fiber-reinforced polymer (FRP) bonding has been widely researched and practiced in the strengthening of concrete members. However, when it comes to steel structures, it is somewhat limited in terms of field applications. One of the most important obstacles to the widespread use of FRP bonding in steel structures is the lack of design codes. This is mainly due to the lack of suitable design models for adhesive joints used to bond FRP laminates to steel substrates. Issues such as the lack of knowledge about the behavior of adhesive joints, the lack of suitable material models for structural adhesives, and analyzing adhesive joints are contributing to the difficulty associated with establishing design models. This paper is mainly concerned with a proposal and verification of a new design model for adhesive joints used to bond FRP laminates to steel beams. The paper, first, shortly reviews the most commonly used failure criteria and presents the background to the newly proposed model. Quasi-static tests were then performed on steel plate and full-scale beam specimens bonded with CFRP laminates to evaluate the new design model. The new design model presented in this paper was found to be accurate in terms of predicting the ultimate load and failure mode of the joints. To illustrate the application of the new design model, an example is appended to this paper.

Flexural Behavior of GFRP RC Beam Strengthened with Carbon Fiber Reinforced Polymer (CFRP) Plate: Cracking Behavior

2015 ◽  
Vol 752-753 ◽  
pp. 610-616 ◽  
Author(s):  
Norhafizah Salleh ◽  
Abdul Rahman Mohd Sam ◽  
Jamaludin Mohd Yatim
Keyword(s):  
Failure Modes ◽  
Fiber Reinforced Polymer ◽  
Flexural Behavior ◽  
Fiber Reinforced ◽  
Cracking Behavior ◽  
Bending Performance ◽  
Reinforced Polymer ◽  
Cfrp Plate ◽  
Reinforced Beams ◽  
Beam Bending

There has been much research conducted on the current performance of Fiber Reinforced Polymer (FRP) as reinforcement. It was due to FRP easier to maintain than steel during construction because of less weight. Laboratory works on the flexural behavior of concrete beams that with GFRP and CFRP use as a plate strengthening for the beam size 2800 x 200 x 250 millimeter. study of the pattern of cracking and failure modes of the beam will be compared between the ten types of beams consisting of steel reinforced beams , beam-reinforced GFRP and GFRP reinforced beams strengthened with CFRP with different lengths. Comparing between the beam bending performance was examined through the ultimate load, cracking and failure modes.

scholarly journals Flexural Strength of Carbon Fiber Reinforced Polymer Repaired Cracked Rectangular Hollow Section Steel Beams

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Tao Chen ◽  
Ming Qi ◽  
Xiang-Lin Gu ◽  
Qian-Qian Yu
Keyword(s):  
Carbon Fiber ◽  
Initial Crack ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Steel Beams ◽  
Fiber Reinforced ◽  
Hollow Section ◽  
Failure Patterns ◽  
Reinforced Polymer ◽  
Cfrp Plate

The flexural behavior of rectangular hollow section (RHS) steel beams with initial crack strengthened externally with carbon fiber reinforced polymer (CFRP) plates was studied. Eight specimens were tested under three-point loading to failure. The experimental program included three beams as control specimens and five beams strengthened with CFRP plates with or without prestressing. The load deflection curves were graphed and failure patterns were observed. The yield loads and ultimate loads with or without repairing were compared together with the strain distributions of the CFRP plate. It was concluded that yield loads of cracked beams could be enhanced with repairing. Meanwhile, the ultimate loads were increased to some extent. The effect of repair became significant with the increase of the initial crack depth. The failure patterns of the repaired specimens were similar to those of the control ones. Mechanical clamping at the CFRP plate ends was necessary to avoid premature peeling between the CFRP plate and the steel beam. The stress levels in CFRP plates were relatively low during the tests. The use of prestressing could improve the utilization efficiency of CFRP plates. It could be concluded that the patching repair could be used to restore the load bearing capacity of the deficient steel beams.

Finite-Element Analysis on Carbon Fiber Reinforced Polymer (CFRP) Plates Reinforcement for the Rigid Joints of Steel Structures

2012 ◽  
Vol 535-537 ◽  
pp. 1997-2001
Author(s):  
Hua Ma ◽  
Li Chun Zhou ◽  
Zhen Bao Li ◽  
Xue Wei Zhang ◽  
Xin Yu Sun
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Steel Structures ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Element Analysis ◽  
Reinforced Polymer ◽  
Cfrp Plate ◽  
Length Width ◽  
Rigid Joints

The method of CFRP plate reinforcement for the rigid joints with complete welding was studied using finite-element analysis. Three models were adopted in analyzed software ANSYS and they are Solid45, Combin14 and Shell181, which used to simulate steel, glue and CFRP plate respectively. The results show that the ultimate bearing capacity of rigid joints improves significantly after using CFRP reinforcement for joints. And the results also show that the level of improvement is relative to the length, width and thickness of CFRP plates.

Experimental Testing of Fiber Reinforced Polymer-Concrete Composite Beam

2010 ◽  
Vol 168-170 ◽  
pp. 549-552
Author(s):  
Yan Lei Wang ◽  
Qing Duo Hao ◽  
Jin Ping Ou
Keyword(s):  
Composite Beam ◽  
Experimental Testing ◽  
Coarse Sand ◽  
Fiber Reinforced Polymer ◽  
Bending Test ◽  
Polymer Concrete ◽  
Fiber Reinforced ◽  
Four Point Bending ◽  
Reinforced Polymer ◽  
Box Beam

A new form of fiber reinforced polymer (FRP)-concrete composite beam is proposed in this study. The proposed composite beam consists of a GFRP box beam combined with a thin layer of concrete in the compression zone. The interaction between the GFRP beam and the concrete was obtained by bonding coarse-sand on the top flange of the GFRP beam. One GFRP box beam and one GFRP-concrete composite beam were investigated in four-point bending test. Load-deflection response, mid-span longitudinal strain distributions and interface slip between GFRP beam and the concrete for the proposed composite beam were studied. Following conclusions are drawn from this study: (1) the stiffness and strength of the composite beam has been significantly increased, and the cost-to-stiffness ratio of the composite beam has been drastically reduced comparing with GFRP-only box beam; (2) a good composite action has been achieved between the GFRP beam and the concrete; (3) crushing of concrete in compression defines flexural collapse of the proposed composite beam..

Shear Failure Analysis of Concrete Beams Reinforced with Newly Developed GFRP Stirrups

2006 ◽  
Vol 324-325 ◽  
pp. 995-998
Author(s):  
Cheol Woo Park ◽  
Jong Sung Sim
Keyword(s):  
Failure Modes ◽  
Shear Failure ◽  
Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Experimental Program ◽  
Shear Stresses ◽  
Fiber Reinforced ◽  
Shear Span ◽  
Reinforced Polymer ◽  
A New Technique

Even though the application of fiber reinforced polymer (FRP) as a concrete reinforcement becomes more common with various advantages, one of the inherent shortcomings may include its brittleness and on-site fabrication and handling. Therefore, the shape of FRP products has been limited only to a straight bar or sheet type. This study suggests a new technique to use glass fiber reinforced polymer (GFRP) bars for the shear reinforcement in concrete beams, and investigates its applicability. The developed GFRP stirrup was used in the concrete instead of ordinary steel stirrups. The experimental program herein evaluates the effectiveness of the GFRP stirrups with respect to different shear reinforcing ratios under three different shear span-to-depth testing schemes. At the same shear reinforcing ratio, the ultimate loads of the beams were similar regardless the shear reinforcing materials. Once a major crack occurs in concrete, however, the failure modes seemed to be relatively brittle with GFRP stirrups. From the measured strains on the surface of concrete, the shear stresses sustained by the stirrups were calculated and the efficiency of the GFRP stirrups was shown to be 91% to 106% depending on the shear span-to-depth ratio.

scholarly journals Effect of Bolt-Hole Clearance on Bolted Connection Behavior for Pultruded Fiber-Reinforced Polymer Structural Plastic Members

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Sang-Pyuk Woo ◽  
Sun-Hee Kim ◽  
Soon-Jong Yoon ◽  
Wonchang Choi
Keyword(s):  
Failure Modes ◽  
Fiber Reinforced Polymer ◽  
Structural Members ◽  
Fiber Reinforced ◽  
Cross Sectional ◽  
Bolted Connection ◽  
Reinforced Polymer ◽  
Connection System ◽  
Structural Plastic ◽  
Bolt Connection

Bolt-hole clearance affects the failure mode on the bolted connection system of pultruded fiber-reinforced polymer plastic (PFRP) members. The various geometric parameters, such as the shape and cross-sectional area of the structural members, commonly reported in many references were used to validate the bolt-hole clearance. This study investigates the effects of the bolt-hole clearance in single-bolt connections of PFRP structural members. Single-bolt connection tests were planned using different bolt-hole clearances (e.g., tight-fit and clearances of 0.5 mm to 3.0 mm with 0.5 mm intervals) and uniaxial tension is applied on the test specimens. Most of the specimens failed in two sequential failure modes: bearing failure occurred and the shear-out failure followed. Test results on the bolt-hole clearances are compared with results in the previous research.

RETROFITTING PERFORMANCE OF REINFORCED CONCRETE ONE WAY SLAB

2016 ◽  
Vol 78 (5-3) ◽  
Author(s):  
Norliyati Mohd Amin ◽  
Nur Aqilah Aziz ◽  
Ilya Joohari ◽  
Anizahyati Alisibramulisi
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Bending Test ◽  
Strength Performance ◽  
Concrete Crack ◽  
Reinforced Polymer ◽  
Structural Capacity

Cracks in concrete structure have always been a big threat on the strength of the concrete. Crack is one of the common deterioration observed in reinforced concrete beams and slabs. Concrete cracking is a random process, highly variable and influenced by many factors. To restore the structural capacity of the concrete damages, retrofitting and strengthening are required. There are several techniques that are used for retrofitting and strengthening reported in the literature [1], [2], [3]. This paper investigates the strength performance of retrofitting and strengthening methods of reinforced concrete one-way slab. Flexural bending test are performed on three different concrete slab of size 1000 mm x 500 mm x 75 mm. The methods that are used for retrofit are epoxy injection and patching and for the strengthening is lamination of carbon fiber reinforced polymer. The slabs were loaded to a certain stage where the cracks were formed for retrofitting and strengthening procedure. The achieved failure mode and load capacity of the concrete slab were observed. The repaired techniques for restoring and improving the structural capacity of cracked concrete slabs were analyzed. The ultimate load achieved for the epoxy injection laminate was 19.60 kN followed by CFRP laminate and patching that were 17.64 kN and 17.03 kN respectively. While the deflection value for the three specimens were 14.42 mm, 4.49 mm and 7.036 mm.  

Applied Element Method Simulation of Fiber Reinforced Polymer and Polypropylene Composite Retrofitted Masonry Walls

2014 ◽  
Vol 17 (11) ◽  
pp. 1567-1583 ◽  
Author(s):  
Saleem M. Umair ◽  
Muneyoshi Numada ◽  
Kimiro Meguro
Keyword(s):  
Numerical Model ◽  
Research Work ◽  
Masonry Wall ◽  
Fiber Reinforced Polymer ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Out Of Plane ◽  
Applied Element Method ◽  
Element Method

In current research work, an attempt is made to simulate the behavior of a newly proposed composite material using 3-D Applied Element Method (AEM). Fiber Reinforced Polymer (FRP) being a strong material provides a significant increase in shear strength. Polypropylene band (PP-band) not only holds the masonry wall system into a single unit but also provides a fairly high deformation capacity at a very low cost of retrofitting. A composite of FRP and PP-band is proposed and applied on the surface of masonry wall. Verification of the proposed numerical model is achieved by conducting experiments on twelve masonry wallets. Out of twelve, six masonry wallets were tested in out of plane bending test and six were tested under in-plane forces in the form of diagonal compression test. Same wallet retrofitting scheme was selected for in-plane and out of plane experiments and all of them were analyzed using proposed 3-D AEM numerical simulation tool. Proposed numerical model has served satisfactory and has shown a fairly good agreement with experimental results which encourages the use of 3D-AEM to numerically simulate the behavior of non-retrofitted and retrofitted masonry wallets.

scholarly journals Shear deformable super-convergent finite element for steel beams strengthened with glass-fiber reinforced polymer (GFRP) plate

2019 ◽  
Vol 46 (4) ◽  
pp. 338-351
Author(s):  
Phe Van Pham ◽  
Magdi Mohareb ◽  
Amir Fam
Keyword(s):  
Finite Element ◽  
Glass Fiber ◽  
Shear Deformation ◽  
Fiber Reinforced Polymer ◽  
Steel Beams ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Partial Interaction

The present study investigates the flexural behaviour of steel beams strengthened by adhesively bonding a glass-fiber reinforced polymer (GFRP) plate to one of the flanges. The model captures shear deformation effects and partial interaction between the steel and GFRP owing to the relative flexibility of the adhesive. A general closed form solution is first developed for the governing coupled system of differential equations. The solution is then used to formulate mechanics-based shape functions and develop a finite element with superior convergence characteristics. The model is used to investigate the response of multi-span continuous beams, determine the strength gained by GFRP strengthening, and quantify shear deformation effects on the response of strengthened beams. A technique capturing partial interaction effects is devised to characterize the flexural strength of Class 3 strengthened beams. A classification limit for strengthened Class 3 sections is also proposed within the framework of the Canadian Standard CAN-CSA S16 (2014).

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