Performance of Concrete and Unrestrained Reinforced Concrete Beam for Fire

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Addis Ababa University


Fire accident is one of the dangerous accidents that could happen to any service structures in unexpected times, it could be ignited intentionally to attack enemies among human being aggression, it could be from the result of terrorism attack which of course common nowadays or it could be from war among enemies. Fire accident by its behaviour a little source is enough to be ignited but its costs much to be controlled. In our country Ethiopia there were so many lives taking and damaging fire accidents occurring for instance in the near past an accident caused on TAITU HOTEL in piazza , an accident in Southern Ethiopia, Hawassa demolishing large number of homes and lives. A repeated and hazardous fire accidents causing loss of valuable human life, failure of structures and the difficult circumstance to make fire accident under control within a shorter time, increase an interest in the design of structures for fire. Now a day there is a good development in using advanced analytical models to determine fire growth within a compartment and have used finite element models of structural components to determine temperatures within a component by heat transfer analysis but the experimental way of determining the performance of structural members for fire is more realistic one. This paper focused in studying the performance of concrete and unrestrained reinforced concrete beams under fire. In this study different concrete surface temperature and duration of fire exposure was considered. Experimental investigation on fire performance of concrete and unrestrained reinforced concrete were carried out and it is discovered compressive strength of concrete reduces up to 30% from initial compressive strength up on exposure to fire causing concrete surface temperature to rise to 246 0c for four hour duration, and residual shear and moment strength of unrestrained reinforced concrete beam reduce to 80% for 246 0c concrete surface temperature sustained for four hours. Key words: Fire duration, Concrete surface temperature, Reinforced concrete beam, Fire rating, Bending moment capacity, deflection, Shear capacity, Compressive Strength, concrete cube.



Fire duration;Concrete surface temperature; Reinforced concrete beam; Fire rating; Bending moment capacity; deflection, Shear capacity; Compressive Strength; concrete cube.