scholarly journals Fatigue Assessment Model of Corroded RC Beams Strengthened with Prestressed CFRP Sheets

2017 ◽  
Vol 11 (2) ◽  
pp. 247-259 ◽  
Author(s):  
Li Song ◽  
Jian Hou
2011 ◽  
Vol 94-96 ◽  
pp. 1012-1017
Author(s):  
Na Ha ◽  
Shen Yuan Fu ◽  
Lian Guang Wang

The main form of interfacial bond stress between prestressed CFRP sheets and the beams of steel reinforced concrete(SRC) are interfacial shear and peel-off stress. The effective transfer of adhesive stress is the fundamental to ensure the structure bearing capacity improved after strengthened. According to the principle of minimum potential energy and combining with the mechanical behavior of prestressed CFRP sheets and the beams of SRC, the calculated formulas of interfacial shear and peel-off stress are deduced under symmetry concentrated loads. The influences of initial strain and the layer of CFRP sheets are discussed. The calculation results show that the effective availability of CFRP sheets is increased with the initial strain increasing under the load. And the interfacial shear and peel-off stress of beam-end are increased simultaneously with the initial strain and the layers of CFRP sheets increasing, which lead to the ends of beams occurred peel-off failure easily.


2011 ◽  
Vol 243-249 ◽  
pp. 929-933
Author(s):  
Na Ha ◽  
Lian Guang Wang ◽  
Shen Yuan Fu

In order to improve the bearing capacity of SRC which is related with deformation and stiffiness, SRC beams should be strengthened by CFRP. Based on the experiment of six pre-splitting steel reinforced concrete beams strengthened with (Prestressed) CFRP sheets, the deformation of beams are discussed. Load-deformation curves are obtained by the experiment. Considering the influence of intial bending moment on SRC beams, the calculated deformation formulas of SRC beams strengthened by (Prestressed) CFRP are deduced. The results showed that the load-deformation curves of normal and strengthened beams respectively showed three and two linear characteristics. The theoretical results which calculated by the formulas of deformation are well agreement with the experimental results.


2018 ◽  
Vol 7 (4) ◽  
pp. 2075 ◽  
Author(s):  
Yasmin Murad

 The use of carbon fiber reinforced polymer (CFRP) sheets is becoming a widely accepted solution for strengthening and repairing rein-forced concrete (RC) structures. To date, the behavior of RC beams, strengthened with 60˚ and 45˚ inclined CFRP sheets, has not clearly explained. An experimental program is proposed in this paper to investigate the flexural behavior of RC beams strengthened with CFRP sheets. CFRP sheets were epoxy bonded to the tension face to enhance the flexural strength of beams inducing different orientation angles of 0˚, 45˚, 60˚ and 90˚ with the beam longitudinal axis. The study shows that strengthening RC beams with CFRP sheets is highly influenced by the orientation angle of the sheets. The orientation angle plays a key role in changing the crack pattern and hence the failure mode. The influence of CFRP sheets was adequate on increasing the flexural strength of RC beams but the ductility of the beams was reduced. The best performance was obtained when strengthening RC beam obliquely using 45˚ inclined CFRP sheets where the specimen experienced additional deflection and strength of 56% and 12% respectively and the reduction in its ductility was the least. It is recom-mended to strengthen RC beams, which are weak in flexure, using 45˚ inclined CFRP sheets.  


2013 ◽  
Vol 20 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Moatasem M. Fayyadh ◽  
H. Abdul Razak

This paper presents the results of both analytical and experimental study on the repair effectiveness of Carbon Fibre Reinforced Polymer (CFRP) sheets for RC beams with different levels of pre-repair damage severity. It highlights the effect of fixing CFRP sheets to damaged beams on the load capacity, mid-span deflection, the steel strain and the CFRP strain and failure modes. The analytical study was based on a Finite Element (FE) model of the beam using brick and embedded bar elements for the concrete and steel reinforcement, respectively. The CFRP sheets and adhesive interface were modelled using shell elements with orthotropic material properties and incorporating the ultimate adhesive strain obtained experimentally to define the limit for debonding. In order to validate the analytical model, the FE results were compared with the results obtained from laboratory tests conducted on a control beam and three other beams subjected to different damage loads prior to repair with CFRP sheets. The results obtained showed good agreement, and this study verified the adopted approach of modelling the adhesive interface between the RC beam and the CFRP sheets using the ultimate adhesive strains obtained experimentally.


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