Experimental behavior of self compacting concrete corbels strengthened with external CFRP

الملخص EN

This research aims to study the influence of using Carbon Fiber Reinforced Polymer (CFRP) strips as an external strengthened and repairing material on the behavior of self-compacting concrete (SCC) Corbels.

The experimental work involved testing twenty self-compacting concrete corbels specimens.

The experimental work is divided into two parts; the first part consists of three groups to investigate the most effective direction, position, bonding type and amount of CFRP strips on the behavior of corbels and utilized it in practice, also to strengthen new variables that are investigated in the second part.

Two groups in part one are strengthened with different numbers of inclined and horizontal direction of CFRP strips, while in the third group the specimens were strengthened with strips of CFRP having different directions and bond types to improve the strength capacity and behavior of corbels.

This improvement is represented by increase cracking load by about (94)% and increase in their ultimate load capacity of strengthening corbels which varies from about (19 to 88)%.

While the second part of experimental work included the following variables: shear span to effective depth ratio (a/d), amount of horizontal steel reinforcement stirrups and repaired damaged corbels.

The reinforced concrete corbels in this part were strengthened and repaired by CFRP strips depending on optimum result that is produced from part one wherefrom position, direction and amount are considered.

It was found for un-strengthened and strengthened corbels having same horizontal secondary reinforcement stirrups that when (a/d) ratio decreases from 0.65 to 0.4 causes increase in cracking and ultimate loads reach (55)% and (35.41)% respectively.

For un-strengthened and strengthened corbels having same (a/d) ratio, it was found an increase in cracking load which varies from (6.66 to 34.78)% and from (18.18 to 52.63) % in ultimate load when horizontal secondary reinforcement stirrups are increased.

It was also found repairing SCC corbels with CFRP strips causes an increase in ultimate load reaching up to (50)% with respect to un-strengthened specimens.

From results it is concluded that strengthened or repaired corbels present stiffer load deflection response than corresponding un-strengthened corbel (control corbel).