Brittle Failure in FRP Plate and Sheet Bonded Beams
ACI Structural Journal, 94 (4):
363--370 (July 1997)Abstract
Analytical and numerical models are presented to simulate the failure
of RC beams strengthened with FRP plates and flexible sheets. Different
failure mechanisms, from ductile to brittle, can be simulated and
verified. The proposed analytical model takes into account the influence
of concrete confinement in the compression zone due to the presence
of the stirrups and the tensile softening properties of concrete.
This allows following more accurately the crack propagation and the
failure mechanism of the flexural member. The numerical model is
based on finite element analysis (FEA), follows the smeared crack
approach, and uses standard elements available in a commercial package.
Comparisons with experimental data obtained from strengthened RC
beams tested in the laboratory are presented. Analytical and numerical
models show good agreement with the experiments. It is shown that
FRP type, thickness, and bonded length produce different types of
failure ranging from FRP rupture to concrete shear failure. Particularly
important is the characterization of the interface (FRP-concrete)
mechanical properties, for which a simple test is proposed.