الفهرس 
CHAPTER 1Only 14 pages are availabe for public view
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Abstract
An experimental and numerical study have been carried out to investigate the shear capacity and behavior of Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) deep beams with web openings located between the provided stirrups in the shear span. The experimental study included fourteen full size simply supported and continuous deep beams with web openings and two solid deep beams as a reference. The beam specimens are divided into two groups, each of them included eight specimens. All the tested deep beams have the same concrete cross section. The first group consists of eight specimens tested simply supported under four point loads and symbolized (DSOU) and the second group consists of eight specimens tested in shear as two equal span continuous deep beams and symbolized (DCOU). All the tested beams constructed from the same UHPFRC mix with a steel fibers volume fraction of 1.5% by volume. The principal studied parameters were the size and location of web openings and the vertical web reinforcement ratio. The provided spacing between stirrups for all the tested beams covers the maximum required by the Egyptian code (ECP-203-2020) and considerably more than the limits required by ACI 318-2019 for normal reinforced concrete. The shear design recommendations used by France Association of Civil Engineers (AFGC-2013) and that of Korea Concrete Institute (KCI-2012) for UHPFRC deep beams have been examined. A finite element code has been used to propose a numerical modeling of the shear capacity and behavior of UHPFRC deep beams with web openings. The results indicated that the shear capacity and behavior of UHPFRC simply supported and continuous deep beams mainly controlled by the size and locations of the web openings in the shear span. For the simply supported deep beams tested in shear, square web opening with height 20% of beam overall height located at the natural load pass caused considerable reduction of the recorded initial diagonal cracking strength and ultimate shear strength of 33% and 43%, respectively, compared with reference solid beam. Increasing the opening width by 75% in the middle third of shear span reduced the ultimate shear strength by 21%. For similar UHPFRC deep beams with same web openings, providing vertical web reinforcement ratio v% twice the minimum required by ECP-203-2020 for normal reinforced concrete enhanced the diagonal cracking strength and ultimate shear strength by 25% and 17%, respectively. The equations used by AFGC-2013 and KCI-2012 for calculating the ultimate shear strength of UHPFRC deep beams are just safe when applied to the tested simply supported deep beams with web openings. The proposed 3-D numerical model predicted successfully the shear capacity and behavior of UHPFRC simply supported and continuous deep beams with web openings.