Abstract:
Reinforced concrete structure is the common structural system used in Ethiopia
and nearly all over the world. Fire represents one of the most severe envi ronmental conditions to which structures may be subjected, and hence, the
provision of appropriate fire safety measures for structural members is an
important aspect of design. Reinforced concrete (RC) structural systems are
quite frequently used in high-rise buildings due to the high structural perfor mance such as strength and durability that it can provide, compared to other
materials. Much of the current knowledge on fire behavior of RC members is
based on fire resistance tests under standard fire scenarios. There have been
no studies under realistic (design) fire scenarios. And thus, there is limitation
reliable experimental data, mathematical models or design specifications for
predicting the fire performance of RC beams under design fire scenarios.
The objective of this study was to analysis the behavior of RC beam
subjected to fire.in Ethiopia there is no sufficient experimental and laboratory
equipment because of this ,there is no enough and detailed explanation under
Ethiopian building code. Therefore, the fire resistance of RC members is an
important issue that needs to be considered in the design of RC buildings.
This thesis presents investigate the behavior of reinforced concrete beam
subjected to fire by using 3D finite element analysis. The first step was
Simulate the structural behaviour of the same beam subjected to mechanical
load and nodal temperature (as nodal temperature time history) calculated
from the first step. Then, the FE models are computed with existing test
data from literature to examine the accuracy of the simulations.
Values from the test and FE model are observed to be close to each other.
There are three parameters to analysis the effect of RC beam subjected
to fire in this paper which is concrete cover, temperature and duration of
time. Results from the analysis indicated that as fire exposure time increases
the material behavior degrades. Since the nodal temperature distribution
increases with an increase in exposure time. When the concrete cover is zero,
the stress along the center of the beam highly decrease and when the concrete
cover is thirty, the stress along the center of the beam highly increases. When
the temperature and duration of time increase, the vertical deflection at mid
span increase.
