Masters Thesis

Punching Shear Behavior of Reinforced Concrete Flat Plates Reinforced with High Strength Steel

Studies on using high strength steel as flexural and shear reinforcement in reinforced concrete members are limited in the literature. Thus, current ACI 318 provisions do not permit using reinforcement steel with a strength higher than 80 ksi as flexural or 60 ksi as shear reinforcement. Reinforcement with a strength of 100 ksi is allowed for confinement in special seismic applications. This research has two objectives. First, it examined the effect of using high strength steel (HSS) as flexural reinforcement in RC flat plates on punching shear resistance. Second, it investigated the feasibility of using the HSS as shear reinforcement to increase the punching shear capacity of RC flat plates. To accomplish these objectives, five half-scale RC flat plates were tested under monotonic loading. the experimental program consisted of one flat plate reinforced with 60 ksi as main reinforcement and has 60 ksi shear reinforcement, and four flat plates reinforced with 100 ksi as main reinforcement and have 0, 60, 80, and 100 ksi shear reinforcement in the form of hoops. the results show that replacement of conventional reinforcement steel (Grade 60) with high-strength steel for the flexural reinforcement increased the punching shear capacity by 6%. Also providing shear reinforcement with yield strengths of 60, 80 and 100 ksi increased the punching shear resistance by 7%, 11%, and 16% respectively. Conclusions were drawn based on the load-deflection relation and the strain distributions between the RC flat plates.


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