The Behavior of High Strength Self-Compacting Reinforced Concrete Corbels Strengthened with NSM Steel Bars

Qasim Muhammed Shakir, Hayder Hussein Kamonna


An experimental investigation conducted with studying the behavior high strength self-compacting reinforced concrete corbels strengthened with NSM steel bars. The experimental work involved testing ten corbel specimens. They are categorized into two groups with two values of shear span/depth ratio (a/d). Each group consists of five specimens, one considered as a control; others were strengthened with four different configurations of NSM steel bars. The load-deflection curves were traced, cracking and ultimate loads were recorded, crack width was measured and crack propagation up to failure was trucked. This research found that strengthening RC corbel with NSM steel bar system improved the failure load significantly by 57% and 41% for a/d of 0.85 and 1.25 respectively. The strengthening system named as "Upside down V-shaped" is more efficient for small values of a/d (a/d <1). The horizontal bars configuration is more convenient for large a/d values (a/d >1); with a/d greater than one, the general mode of failure is of Bond type.  Also, it is found that the strengthening of specimens results in some elimination in ductility with a value depending on the strengthening configuration.


high strength; self-compacting; NSM steel bar; strengthening; corbels

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