Influence of Initial Crack-depth Ratio on Dynamic Fracture
Characteristics of FRP Reinforced Concrete
Abstract
Abstract: In order to study the dynamic fracture characteristics of FRP
reinforced concrete, the three-point bending experiment of FRP
reinforced concrete beams with different initial crack-depth ratios was
carried out by using MTS-810 hydraulic servo experiment machine. The
initial crack-depth ratios are 0.2, 0.3, 0.4, 0.5 and 0.6 respectively.
The effects of different initial crack-depth ratios on the load-crack
opening displacement curve, failure process, the increment of critical
crack-depth ratio and flexibility coefficient of FRP reinforced concrete
three-point bending beam specimens were analyzed by displacement
controlled monotonic loading method. Combined with Pearson correlation
experiment formula, the correlation between initial crack-depth ratios
and different fracture parameters was quantitatively analyzed. The
conclusions can be drawn that, there are three obvious critical points
in the fracture process of FRP reinforced concrete three-point bending
beam: the starting point of concrete crack, the first peak point and the
ultimate bearing capacity point. With the increase of the initial
crack-depth ratio, the crack initiation load decreases, but the first
peak load and ultimate load increase first and then decrease. It is
found that the stress intensity factors of the three critical points
increase first and then decrease with the increase of the initial
crack-depth ratio, and when the initial crack-depth ratio is 0.4, the
three kinds of stress intensity factors all reach the maximum value. The
increment of critical crack-depth ratio and flexibility coefficient of
FRP reinforced concrete beams are related to the initial crack-depth
ratio, which can be used to reflect the influence of initial crack-depth
ratio on the deformation capacity of concrete specimens. Keywords: FRP
reinforced concrete; dynamic fracture; the initial crack-depth ratios;
stress intensity factors; increment of critical crack-depth ratio;
flexibility coefficient