It is therefore interesting and important from design perspective,
to investigate the behavior of RC beams of different aspect
ratios under dynamic loading. Currently, as per authors’ knowledge
no such tests are available in the literature. It is generally difficult,
time consuming and economically demanding to perform such
tests covering a range of aspect ratios and loading rates. On the
other hand, numerically the problem can be solved relatively easily,
provided the numerical model is able to capture the dynamic
behavior of RC beams realistically. In this paper, it is attempted
to address the issue of the influence of high loading rate on the failure
mechanism and resistance of structural elements with different
aspect ratios. A reinforced concrete cantilever beam with four
different aspect ratios from 2 to 8 is numerically tested under a
range of loading rates. The reinforcement details of the beam are
kept the same for all the aspect ratios. First, the beams of four different
ratios are analyzed under static loads and the known influence
of the aspect ratio under static loading is confirmed. Then the
beams with different aspect ratios are subjected to different levels
of high rate loading to understand the influence of loading rate in
each case.
Microplane model with relaxed kinematic constraint [8] has
been followed as the constitutive law for concrete, while the rate
dependency is considered as per the model by Bazˇant et al.
[9,10]. The formulations followed in this work have been previously
validated against several examples and is known to predict
the static as well as dynamic behavior of RC structural elements
with high confidence [1,11,12].