Finite Element Analysis Of Reinforced Concrete Beam Subjected To Fire

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.