scholarly journals Steel Fibres: Effective Way to Prevent Failure of the Concrete Bonded with FRP Sheets

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
V. Gribniak ◽  
A. K. Arnautov ◽  
A. Norkus ◽  
R. Kliukas ◽  
V. Tamulenas ◽  
...  

Although the efficiency of steel fibres for improving mechanical properties (cracking resistance and failure toughness) of the concrete has been broadly discussed in the literature, the number of studies dedicated to the fibre effect on structural behaviour of the externally bonded elements is limited. This experimental study investigates the influence of steel fibres on the failure character of concrete elements strengthened with external carbon fibre reinforced polymer sheets. The elements were subjected to different loading conditions. The test data of four ties and eight beams are presented. Different materials were used for the internal bar reinforcement: in addition to the conventional steel, high-grade steel and glass fibre reinforced polymer bars were also considered. The experimental results indicated that the fibres, by significantly increasing the cracking resistance, alter the failure character from splitting of the concrete to the bond loss of the external sheets and thus noticeably increase the load bearing capacity of the elements.

2015 ◽  
Vol 744-746 ◽  
pp. 113-117
Author(s):  
Cheng Fang Sun ◽  
Chun Ming Chen ◽  
Qian Gu

A contrast investigation of the seismic behavior of unreinforced masonry walls with window openings strengthened with Carbon Fibre Reinforced Polymer (CFRP) sheets and sprayed Glass Fibre Reinforced Polymer (GFRP) is presented. Three wall specimens in the scale of 1/2 were tested by the horizontal cyclic loading combined with constant gravity loads. The seismic strengthening effects by two different FRP retrofitting schemes are compared in aspect of the hysteresis response, deterioration of rigidity and ability of energy dissipation. The experimental results indicate that the increasing degree of the improvement of seismic behavior of the SGFRP-strengthened wall are significantly superior to that of the wall strengthened with epoxy-based CFRP; and the overcoat of sprayed GFRP can bond tightly and work well together with the masonry to play a critical role in earthquake resistance.


2021 ◽  
Vol 48 (1) ◽  
pp. 1-15 ◽  
Author(s):  
A. Kumari ◽  
A.N. Nayak

This paper presents the test results of an experimental study on shear deficient reinforced concrete (RC) deep beams strengthened with externally bonded glass fibre reinforced polymer (GFRP) sheets and mechanical anchors. A total of nine deep beams are prepared. One beam is kept as un-strengthened. Four beams are strengthened using GFRP sheets only at shear spans by varying the number of layers. The remaining four beams are strengthened using both GFRP sheets and mechanical anchors at shear spans. The shear capacity, failure mode, and deflections are studied with respect to the different strengthening techniques. The optimum enhancement in shear capacity of these beams is observed as 25.64% and 55.5% for GFRP strengthened beams and GFRP strengthened anchored beams, respectively with respect to the un-strengthened beam. Moreover, the experimental results are also compared with the results predicted from the design guidelines and models available in the literature, which shows good agreement.


2007 ◽  
Vol 34 (3) ◽  
pp. 331-339 ◽  
Author(s):  
C Klowak ◽  
A Memon ◽  
A A Mufti

This paper outlines the static and fatigue behavior of cast-in-place, second-generation steel-free bridge decks. Although cast monolithically, the first bridge deck was divided into three segments. The first segment was reinforced with steel, according to conventional design. The other two segments were steel-free designs with internal crack-control grids, one consisting of carbon-fibre-reinforced polymer (CFRP) and the other consisting of glass-fibre-reinforced polymer (GFRP). This hybrid CFRP or GFRP and steel strap design is called the second generation of the steel-free concrete bridge deck. The hybrid system limits the width of any longitudinal cracks that develop and eliminates corrosion from within the deck slab. All three segments were tested under cyclic loads of 222 and 588 kN to investigate fatigue behavior. The second bridge deck comprises an internal panel and two cantilevers and also incorporates a complete civionics system. The static tests outlined in this paper are useful in the development of the fatigue theory, which was derived from the fatigue testing of the first bridge deck.Key words: steel-free, cantilever, fatigue testing, static testing, glass-fibre-reinforced polymer, carbon-fibre-reinforced polymer, civionics.


Author(s):  
Shalini G V

The construction material mainly reinforced concrete is being used extensively for various type of construction projects. However, deterioration of RC structures is recognized as a major problem worldwide. Extension of the structures’ life is an inevitable need for a healthy planet. Any deficiency caused to the members of the structure may affect the life of structure. Therefore, it is important that the members should provide adequate strength (for which it is designed) throughout its operational life. But, it has been observed that due to alteration in purpose of use of structure (very common in mega cities), improper design and deficiency caused due to earthquake, blast and impacts in structural members and as a result in the members structure can possibly be subjected to loads which have higher magnitude compared to its design loads. This study is based on experimental investigation to assess the behavior of CFRP & GFRP wrapped concrete under compressive loads. For this purpose, M30 grade concrete specimens have been casted and wrapped it with Glass and Carbon FRP and its strength against compressive loads have been found.


Author(s):  
Allan Manalo ◽  
Mac Pac

Fibre composite guardrails are increasingly being used to ensure safety of workers from fall-from-height incidents due to its high strength, high corrosion resistance and low maintenance. In this study, the structural behaviour of pultruded glass fibre-reinforced polymer (GFRP) guardrail was evaluated following AS1657-1992. GFRP guardrail systems mounted on top and side of a steel beam with different joint connectors are loaded horizontally to top of the guardrail post and to the middle of the guardrail member. The results showed that the guardrail system with joints connected with either polypin or rivets combined with epoxy exhibited 20% higher failure load and almost double the stiffness than those connected using polypin or rivets alone. The side-mounted guardrail failed due to failure of the base connector while the guardrail mounted on top of the beam failed at the joints indicating that the structural behaviour of GFRP guardrail system is affected mainly by the type of joints.


2014 ◽  
Vol 60 (1) ◽  
pp. 145-159 ◽  
Author(s):  
M.C. Sundarraja ◽  
P. Sriram

Abstract The main objective of this investigation is to assess the feasibility of strengthening of corroded (damaged) square hollow steel tubular sections subjected to compression and to develop or predict the suitable wrapping scheme of fibre reinforced polymer (FRP) to enhance the structural behaviour of it. For this study, compact mild steel tubes were used with the main variable being FRP characteristics. Carbon fibre reinforced polymer (CFRP) fabrics was used as horizontal strips (lateral ties) with other parameters such as the number of layers and spacing of strips. Among fourteen specimens, six were externally bonded by CFRP strips having a constant width of 50mm with a spacing of 20mm and the remaining six were externally bonded by CFRP strips having a constant width of 70mm with a spacing of 20mm, two columns were unbonded. Experiments were undertaken until the failure of columns to fully understand the influence of FRP characteristics on the compressive behaviour of the square sections including their failure modes, axial stress-strain behaviour, enhancement in the load carrying capapcity, and effect of distribution of CFRP layers. Finally, the behaviour of externally bonded hollow tubular sections was compared with one another and also with the control specimens. Evaluation of the results will lead to optimum CFRP jacketing/ wrapping arrangements for the steel tubes considered here.


2017 ◽  
Vol 21 (4) ◽  
pp. 545-556 ◽  
Author(s):  
Allan Manalo ◽  
Mark Jackson

Fibre composite guardrails are increasingly being used due to its high strength, high corrosion resistance and low maintenance, although there is very limited information on their structural behaviour. In this study, full-scale pultruded glass fibre reinforced polymer guardrail is experimentally investigated to have a better understanding on the behaviour of fibre composites guardrail system. Glass fibre reinforced polymer guardrail systems mounted on top and side of a steel beam with different joint connectors are loaded horizontally to top of the guardrail post and to the middle of the guardrail member. The results showed that the guardrail system with joints connected with either polypin or rivets combined with epoxy exhibited 20% higher failure load and almost double the stiffness than those connected using polypin or rivets alone. The side-mounted guardrail failed due to failure of the base connector, while the guardrail mounted on top of the beam failed due to failure of the joint connector. Finally, the results of the study indicated that the structural behaviour of glass fibre reinforced polymer guardrail system is affected mainly by the type of joints connecting the different members.


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