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Prevention of Debonding Failure of Intermediate Anchor to Eliminate Premature Shear Failure of Flexurally Strengthened Reinforced Concrete Beams

  • Research Article - Civil Engineering
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Abstract

This research proposed an optimal method of intermediate anchor to prevent premature debonding failure of anchor plate for eliminating premature shear failure of CFRP laminate flexurally strengthened reinforced concrete (RC) beam. In the experimental programme, seven RC beam specimens were prepared which included un-strengthened control beam and flexurally strengthened beams with CFRP laminate. The flexurally strengthened beams were further shear strengthened using L-shaped intermediate anchors based on proposed and conventional methods. The experimental results of specimens were compared with the numerical results. Theoretical model had also been proposed to predict the debonding failure of intermediate anchors. Results showed that the anchors obtained based on the proposed design guideline prevented premature debonding failure of anchor plates completely and thus, the proposed intermediate anchored strengthened beams did not show premature shear failures. Whereas beams having the anchor plates based on conventional method failed by premature debonding of anchor plates followed by premature shear. The proposed intermediate anchors significantly increased the ultimate loads and ductility of the beams as compared to conventional one. It also reduced the number and widths of cracks in shear span. The theoretical model could predict the debonding failure load of intermediate anchor which was comparable with the experimental finding. Finally, numerical model predicted the structural behaviour of proposed intermediate anchored strengthened beams satisfactorily.

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Abbreviations

V ext :

Maximum shear force of strengthened beams for point load

M us :

Maximum moment of strengthened beams for point load

V max :

Maximum shear resisting capacity of the beam

V c :

Shear force resisted by concrete

v c :

Shear stress of concrete

V c :

Shear force resisted by shear link

A s :

Area of the steel bar

A′s :

Area of the shear link

f ys :

Yield strength of the shear link

N :

Number of shear link

ϕ link :

Diameter of the shear link

b :

Width of the beam

d :

Effective depth of tensile reinforcement

d′:

Effective depth of compression reinforcement

s :

Spacing of shear link

V p :

Shear resisting capacity of L-shaped intermediate anchor

A p :

Area of L-shaped intermediate anchor

f yp :

Yield strength of L-shaped intermediate anchor

F bu :

Bond strength of concrete

β :

Coefficient of concrete bond strength

f cu :

Compressive strength of concrete

A bond :

Required bond area to resist external shear force

A plate surface :

The surface area of the plate

H :

Depth of beam

t p :

Thickness of the plate

w p :

Width of the plate

S.F.:

Safety factor of bond strength

V pb :

The shear force resisted by bond strength of anchor plates

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Authors and Affiliations

  1. Department of Civil Engineering, Universiti Tenaga Nasional, Kajang, Malaysia

    Md Ashraful Alam

  2. Department of Civil Engineering, University of Malaya, Kuala Lumpur, Malaysia

    Mohd Zamin Jumaat

Authors
  1. Md Ashraful Alam
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  2. Mohd Zamin Jumaat
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Correspondence to Md Ashraful Alam.

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Alam, M.A., Jumaat, M.Z. Prevention of Debonding Failure of Intermediate Anchor to Eliminate Premature Shear Failure of Flexurally Strengthened Reinforced Concrete Beams. Arab J Sci Eng 40, 2219–2232 (2015). https://doi.org/10.1007/s13369-015-1739-1

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  • DOI: https://doi.org/10.1007/s13369-015-1739-1

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