Splice Length of Steel Reinforcing Bars in Ultra high performance fiber reinforced concrete beams

Abstract

Due to the lack of test data on the bond strength of deformed reinforcing bars embedded in Ultra-high performance fiber reinforced concrete (UHPFRC) ACI-318-19 building code requirements imposed an upper limit of 70 MPa on compressive strength of concrete that may be used in calculating tension development length and tension splice length To evaluate the applicability of ACI-318-19 design provisions for calculating splice length of UHPFRC sixteen simply supported beam specimens were fabricated and tested in this experimental program Each beam was designed with two deformed bars spliced in a constant moment region on the tension side at mid-span The test parameters include: 1) inclusion of the steel fiber 2) splice length 3) with and without coarse aggregate and 4) bar size Experimental results indicated that inclusion of a 1 5% volume ratio of fibers increased the bond strength between UHPFRC and reinforcing bars Additionally the splitting bond failure of beams with fibers were more ductile and allowed propagation of the flexural cracks extended upward to the top surface The tesr results also show that UHPFRC beams could significantly reduced the required splice length based on ACI-318-19 design provisions and the upper limitations of concrete strengths can be adjusted to over 100 MPa

Date of Award	2019
Original language	English
Supervisor	Chung-Chan Hung (Supervisor)