Steel fiber-reinforced concrete beams: Long-term performance and expert system analysis

During the last decade steel fiber reinforced concrete (SFRC) has been increasingly used as a construction material. In structural applications, steel fibers have demonstrated the ability to inhibit tensile cracking, improve toughness, and resist impact loading. Hence, steel fibers added to concrete should be considered a reliable supplement to enhance strength and toughness properties of SFRC beams. This dissertation presents analytical methods to analyze the behavior of SFRC beams in compression, tension, flexure, shear, torsion, toughness, and deflection. This behavior is incorporated in an optimization algorithm to design SFRC beams. A study on the long-term deflections of SFRC is conducted. The results of this study along with the optimization algorithm are utilized to develop an expert system for SFRC beams design.;The section of optimal design of SFRC beams based on the bending, shear, torsion, and toughness characteristics consists of a computer algorithm, parametric study results, comparison of the optimized results with POWELL's and DFP methods, and sensitivity analysis of the variables.;The deflection study of SFRC beams includes a computer algorithm that predicts the short-term and long-term deflections. The analytical predictions are compared against experimental results and found to be in good agreement.;The expert system for designing SFRC beams covers six knowledge bases; namely, singly reinforced SFRC beams, doubly reinforced SFRC beams, shear strength of SFRC beams, torsion strength of SFRC beams, immediate and long-term deflections of SFRC beams, and required toughness of SFRC beams.