Shear Critical Deep Beams with Embedded Functionally Graded Concrete Struts
Jacob Yager, Neil A. Hoult, Evan C. Bentz, and Joshua Woods
Appears on pages(s):
deep beams without transverse reinforcement; distributed fiberoptic strain sensing; fresh-on-fresh concrete casting; functionally graded concrete (FGC); low-carbon concrete; low-cement content concrete; strut-and-tie model (STM)
In this research, novel functionally graded concrete deep beams without transverse reinforcement for transfer girder applications were constructed with varying shaped embedded high-strength struts surrounded by low-cement content concrete. The cement content in the low-cement content concrete also varied, with a maximum total beam cement reduction of 47% compared to the control. The placement method also varied, further revealing issues with fresh-on-hardened concrete casting. The beams were tested in three-point bending and monitored using distributed fiber-optic
sensors (DFOS) and digital image correlation. The results of the
tests revealed that diagonal-shaped embedded struts designed for three-point bending had the highest load capacity increase of up to 26%. However, using shapes not compatible with three-point bending resulted in load capacity decreases. DFOS also enhanced the understanding of strut-and-tie mechanisms, allowing for the visualization of the strain distribution in struts and quantifying formations of the strut and tie.