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Experimental
and numerical analysis of end anchored steel plate and CFRP
laminate flexurally strengthened r. c. beams
Mohd Zamin
Jumaat and Md. Ashraful Alam*
Department of Civil Engineering, University of Malaya, 50603
Kuala Lumpur, Malaysia.
*Corresponding author. E-mail:
ashraf_arif2003@yahoo.com or
ashraful@perdana.um.edu.my. Tel: +6-0163040495.
Accepted 22 January, 2010. |
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End
anchors have been shown to significantly reduce premature
plate end debonding failure of plate bonded strengthened
reinforced concrete (r. c.) beams. One of the main interest
in designing end anchors is to determine the minimum or
optimal length of end anchors for a given thickness and
height of the end anchor. This paper presents experimental
and numerical studies in determining those optimum lengths
for steel plate and carbon fibre reinforced polymer (CFRP)
laminate flexurally strengthened r. c. beams. In the
experimental programme, seven r. c. beams were cast. One
beam was tested in the un-strengthened condition to act as
the control beam. Three beams were strengthened with steel
plates and another three beams were strengthened with CFRP
laminates. From each group of the strengthened beams, one
beam was strengthened without any end anchor, one was end
anchored using the optimum anchorage length and the last one
was end anchored using an arbitrarily 200 mm anchorage
length. The optimum length for the end anchor used in this
study was derived from analyzing the interfacial stress
diagram of the strengthened beams and was found to be
approximately 100 mm. The beams were also modelled using FEM
(LUSAS). The results indicate that the optimized 100 mm
anchorage length plates were able to prevent premature plate
end debonding failure of steel plate and CFRP laminate
strengthened beams satisfactorily. It could also be seen
from the results that beams with end anchors had a higher
failure loads and had more ductile behaviour than the
un-anchored strengthened beams. Results also show that the
optimized end anchored strengthened beams had identical
structural behaviour to that of the longer end anchored
strengthened beams. The numerical results are able to
predict the behaviour of the beams satisfactorily.
Key words:
Premature debonding, end peeling, CFRP laminate, steel
plate, end anchors. |
