Analysis for behavior of reinforcement lap splices in deep beams

Abstract EN

The present study includes an experimental and theoretical investigation of reinforced concrete deep beams containing tensile reinforcement lap splices at constant moment zone under static load.

The study included two stages: in the first one, an experimental work included testing of eight simply supported RC deep beams having a total length (L = 2000 mm), overall depth (h= 600 mm) and width (b = 150 mm).

The tested specimens were divided into three groups to study the effect of main variables: lap length, location of splice, internal confinement (stirrups) and external confinement (strengthening by CFRP laminates).

The experimental results showed that the use of CFRP as external strengthening in deep beam with lap spliced gives best behavior such as increase in stiffness, decrease in deflection, delaying the cracks appearance and reducing the crack width.

The reduction in deflection about (14-21) % than the unstrengthened beam and about (5-14) % than the beam with continuous bars near ultimate load.

Also, it was observed that the beams with unstrengthened tensile reinforcement lap splices had three types of cracks: flexural, flexural-shear and splitting cracks while the beams with strengthened tensile reinforcement lap splices or continuous bars don’t observe splitting cracks.

In the second stage, a numerical analysis of three dimensional finite element analysis was utilized to explore the behavior of the RC deep beams with tensile reinforcement lap splices, in addition to parametric study of many variables.

The comparison between the experimental and theoretical results showed reasonable agreement.

The average difference of the deflection at service load was less than 5%.