Shear strengthening of concrete members with unbonded transverse reinforcement

With the advent of strain-hardening cementitious composites (SHCC), an opportunity for alternative jacketing solutions is presented, where the internal confinement exerted by the fibers in the material may effectively encase the structural component, thereby enhancing the strength and deformation capacity in the critical regions. This concept is explored in the present paper through testing of four pre-damaged prismatic flexural reinforced concrete members with various reinforcing deficiencies. Thin SHCC jackets constituted of a fiber-reinforced Engineered Cementitious Composite (ECC) are used to replace the damaged cover without any additional confining reinforcement. An advantage of cover replacement is that strengthening is achieved without altering the dimensions of the members. The experimental results documented the SHCC jackets’ effectiveness as a rehabilitation strategy, enhancing both the strength and ductility of the retrofitted elements and mitigating the deficiency in transverse reinforcement detailing. The strength recovery showed that the cover-thin SHCC jacket sufficed to enhance flexural and shear resistance through confinement and mobilization of stress transfer at the interface with the encased core.

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The method of analysis of a reinforced concrete section under bending in the post-yield range

Budownictwo i Architektura ◽

10.35784/bud-arch.2182 ◽

2013 ◽

Vol 12 (1) ◽

pp. 123-130

Author(s):

Jacek Korentz

Keyword(s):

Reinforced Concrete ◽

Analytical Procedure ◽

Concrete Cover ◽

Transverse Reinforcement ◽

Concrete Members ◽

Extreme Loads ◽

Concrete Confinement ◽

The Moment ◽

The Relationship ◽

Concrete Section

Predicting the behavior of plastic hinges subjected to large inelastic deformations caused by extreme loads such as earthquakes plays an important role in assessing maximum stable deformation capacities of framed concrete structures. This paper presents an analytical procedure for analysing the behaviour of a reinforced concrete section under bending in the post-yield range. The following stages of section behaviour are defined as the uncracked; first cracked; yielding; cover crushing; cover spalling; buckling of bars; and limit stages. The relationship between the moment and curvature in these stages, including the effects of concrete confinement, the spalling of the concrete cover, and the inelastic buckling of the reinforced bars, are considered. The results obtained from analytical calculations have are compared to the results obtained from a computer analysis. The presented method makes it possible to estimate the ductility of reinforced concrete members with various longitudinal and transverse reinforcement.

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