The Role of Bond in Shear Transfer of Shear Critical Reinforced Concrete Slender Beams
No Thumbnail Available
Date
2022-01
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Due to its complex nature, the effect of bond loss between concrete and longitudinal bar
on the shear transfer mechanism lacks a complete framework. So far, all ranges of bond
losses are considered as a total bond loss, leaving no gap to address intermediate ranges.
Advancement in this area will aid in the assessment of the service life time of various
structures and provide insight for rehabilitative engineers in their efforts. An experimental
program was undertaken to investigate two ranges of bond losses, complete bond loss and
bond losses induced by transversal cracks in relation to the effect of the location of the
bond deterioration.
In first set Pullout test was used to determine the best approach for bond cutting without
compromising the cracking pattern. This set experimented on the location of the artificial
bond cut. It included the control beam and two beams with artificial bond cutting material
covering 75% of their shear span, with a sole difference being the location of the artificial
bond cut. The second set experimented on bond losses induced by transversal cracks. The
transversal cracks were induced by introducing slits and a water proof tape was wounded
around the slits to simulate the bond deterioration zone. This set included four beams with
75% and 50% of their shear span designed to imitate transversal cracks.
During testing, the shear strain at specified points of the 8 beams were measured to
compare the two sets. A number of mold strain gauges were also used in the second set of
specimens to monitor the transfer of shear force to the web. The results of the beam
specimens in the first set have attained 90% up to 100% of their flexural capacity, while
the control has attained 53% of the flexural capacity. It was also observed that the critical
diagonal crack initiation, propagation and location is severely affected by the experimental
variables. Finally, it was observed that the location of the bond cut or bond deterioration
resulted in a different effect on the two sets.
Description
Keywords
Role of Bond, Reinforced Concrete Slender Beams, Shear