Effects of fire on the bending strength of high-strength reinforced concrete beams

• Main Authors: De las Llagas, Jose Leo E., Martinez, Ma. Klarissa G., Viernes, Alexander P.
• Format: text
• Language: English
• Published: Animo Repository 2010
• Subjects: High strength concrete; Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/7936
• Institution: De La Salle University

High Strength Concrete (HSC) is now used in the constructions of high rise buildings, offshore constructions, bridges, and the like. What sets it apart from Norman Strength Concrete (NSC) is that it can sustain much greater forces therefore it can be made slimmer making it more workable and space efficient. However, it was discussed in other studies that HSC performs inferior to NSC when exposed to high temperature. The National Structural Code of the Philippines, NSCP, has limited provisions and guidelines for HSC when subjected to fire. This study investigated the effects of fire on the bending strength of high strength reinforced concreter beams. In this research, three grades of concrete compressive strengths were used 49 MPa and 63 MPa for high strength, and a normal strength of 35 MPa for comparison purposes. Twenty-four (24) concrete beams, with dimensions of 150 mm x 250 mm x 1050 mm, and thirty-six (36) concrete cylinders were produced and then subjected to fire in four different times of exposures 0 hours, 1 hours, 2 hours, and 3 hours. The beams and cylinders underwent testing and the data were analyzed. The experimental and theoretical moments for each specimen at the elastic and ultimate stages were obtained and evaluated. It was found that HSC has a much higher rate of deterioration as compared to NSC after being exposed to fire.