Experimental Study of the Effect of Fiber Additives to Concrete Materials in RC Moment-Resisting Frames with Manufacturing Errors

Reinforced concrete structures with moment resisting frames are one of the most widely used structural systems in the world. High ductility, acceptable strength, ease of implementation, and fewer architectural limitations compared to other structural systems are the positive features of reinforced concrete moment-resisting frames. Construction errors and the use of improper mixing designs for concrete materials are generally the causes of the poor performance of these structures. In the present study, an attempt has been made to investigate the effect of concrete additives on the performance of conventional concrete structures with fabrication errors in an experimental study. three one-third-scale experimental specimens were constructed using Steel Fibers (SF) and Air Entering Admixture (AEA) materials at the beam-column joints. The samples were subjected to cyclic quasi-static loading in the laboratory. Seismic parameters of stiffness, ductility, ultimate strength, and energy dissipation capacity were obtained and evaluated from the hysteresis diagrams of experimental tests. The experimental results showed that the use of steel and polypropylene additives enhances the seismic performance of concrete structures and improves the parameters of stiffness, ultimate strength, and energy dissipation capacity; However, they do cause a slight decline in ductility. It was also concluded that if there is a construction error in the structure, the use of steel fibers additives will provide better behavior than a reinforced concrete frame with conventional materials.