Investigation of replacement of stirrups with steel fibers in self-compacting reinforced concrete haunched beams

Reinforced Concrete Haunched Beams (RCHBs) are important structural members in the construction sector. Usage of steel fiber reinforced concrete (SFRC) can be considered as a possible replacement to use of traditional shear in RCHBs. Usually one of the disadvantages related to the use steel fiber is that adding fiber to a regular concrete mixture can occur large problems in workability of concrete. Therefore, the use of self-compacting concrete (SCC) is a suitable solution to such a problem and can enhance the workability of fresh concrete. This thesis presents the experimental study for one type of RCHBs. The experimental work consists of 9 self-compacting fiber reinforced concrete (SCSFRC) beams, which is classified into 6 RCHBs and 3 prismatic beams which examined under four-point loading. One type of steel fiber that has a hooked end was used in this study. The studied variables included inclination angle, beam type, and steel fiber percentage. These variables have been significantly influential on the shear behavior of RCHBs. The results show that the higher inclination angle of SCSFRC haunched beams has a negative influence on shear load capacity due to increase in shear stress. Also, the results indicated that the combination of the use SCC and steel fibers in RC beams can significantly improve shear strength, post-cracking behavior, and ductility. Steel fibers both reduced the crack width and converted the failure mode from brittle and sudden to ductile. Furthermore, the results showed that the use of 1% volumetric ratio can be a substitute for minimum shear reinforcement in RCHBs