The coefficient of transverse thermal expansion (CTE) of fiber
reinforced polymers (FRP) bars can be substantially higher than
that of concrete. Under temperature increase, this thermal
incompatibility can result in tensile stresses that may produce
cracking in concrete around the FRP bar. Nonlinear finite
element (FE) analysis is employed to study this phenomenon in
a concrete cylinder concentrically reinforced with an FRP bar.
The FE analysis is first compared with a simplified elastic
solution. Then, parametric studies of the main variables that are
believed to influence the overall behavior of the problem at
hand are presented. The studied variables include CTE and
transverse modulus of elasticity of FRP bars, concrete strength,
and concrete-cover-to-bar-diameter ratio. The effect of each
parameter on the temperatures at which cracking starts to occur
and at which a crack propagates to the outside surface of the
concrete cover (splitting crack) is evaluated. Based on the
analysis of the finite element results, it is concluded that FE
analysis shows conservative predictions of transverse thermal
loading of studied concrete cylinders concentrically reinforces
with FRP bars. |
