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International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 5, September – October (2013), © IAEME 152 EXPERIMENTAL VERIFICATION OF THE MINIMUM FLEXURAL REINFORCEMENT FORMULAS FOR HSC BEAMS M. SAID1 & T. M. ELRAKIB2 1Lecturer, Civil Eng. Dep., Shoubra Faculty of Eng., Benha University, Egypt 2Lecturer, Housing and Building National Research Center, Cairo, Egypt ABSTRACT The main objective of the current research is to establish experimental data for minimum flexural reinforcement, min, of high strength concrete (HSC) rectangular beams. Nine full-scale singly reinforced beams with flexural reinforcement ratios varying from 50% to 100% of the minimum limit specified by the ACI 363R-35 were tested in flexure. Concrete compressive strengths of 52, 73 and 96.5 MPa were used. The test results including crack patterns, deflections and strains in the tensile flexural steel bars show that a 25 % reduction of the ACI 363R-35 limit for the min would result in a satisfactory flexural beam behavior. The experimental results of this study are compared with the limits specified by available codes and researches. Keywords: High Strength Concrete, Beams, Minimum Reinforcement, Ductility. INTRODUCTION High strength concrete (HSC) provides a better solution for reducing sizes and weights of concrete structural elements. The major part of the application of high strength concrete concerns particular structures such as offshore platforms and the lower story columns of high-rise buildings. HSC correlates with improvements in its other engineering properties (tensile strength, creep coefficient, etc.), however, it fractures suddenly and forms a smooth failure plane [1, 2]. However, in designing a reinforced concrete member, it is important to insure that the member will not exhibit brittle failure and will be capable of sustaining large deformations near maximum load. This capability gives ample prior warning before failure. Because concrete becomes increasingly more brittle as its compressive strength is increased, guaranteeing adequate ductility represents one of the primary design concerns when HSC is involved. Moreover, in some situations and for one reason or another, the concrete section dimensions are bigger than required by strength consideration to the extent that the flexural element does not need tensile INTERNATIONAL JOURNAL OF CIVIL ENGINEERING AND TECHNOLOGY (IJCIET) |
