الفهرس 
LITERATURE REVIEWOnly 14 pages are availabe for public view
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Abstract
The behaviour of precast-prestressed hollow core slabs has been
extensively studied when they are subjected to positive bending
moments: a typical practical application of these slabs. However, in
many projects the architect may require to have an overhanging part of
the roof to act as a cantilever. In doing so, and using precastprestressed
hollow core slabs, the slabs would be subjected to negative
moments. This situation violates the design concepts of hollow core
slabs. In such circumstances, the structural engineer designing the roof
has two choices: either to change the architectural plan which is bonded
by the approval of the architect or to renounce using the hollow core
slabs altogether. On another frontier, use of Carbon Fiber Reinforced
Polymers (CFRP) strips in strengthening reinforced concrete elements,
has increased rapidly. The conventional alternative for CFRP laminates
is the use of steel plates bolted to the concrete surface or increasing the
cross section dimensions using reinforced concrete jackets. The major
disadvantages of steel plate are corrosion of steel and the need for
technical labour and heavy equipment. Reinforced concrete jackets also
require labour and is time consuming. CFRP strips have non-corrosive
characteristics, high strength-to-weight ratio and good fatigue
properties. These characteristics significantly increase the service life
of structures compared to the conventional strengthening techniques.
An Extensive experimental investigation is carried out to investigate
the behaviour of the precast-prestressed hollow core slabs when they are subjected to negative bending moments. A proposed strengthening
detail to increase the negative moment resistance of hollow core slabs
using bonded CFRP strips is studied. The strips were bonded to the top
side of full-scale precast prestressed hollow core slabs in the negative
moment zone in different configurations. In some configuration, the
bond between the prestressing strands and the concrete was initially
broken in the negative moment zone. The slabs with the bonded CFRP
strips were tested in f1exure to failure and the load-deflection behaviour
was recorded. The results of the tests are presented and the strength
enhancement of the hollow core slabs using the proposed technique is
reported. The increase in the negative moment resistance of the CFRP-
bonded hollow core slabs experimentally determined is also compared
to the prediction of the CSA 806-02 and ACI 440.2 R-02 rovisions for
predicting the moment resistance of concrete elements with bonded
CFRP strips.