Shear Failure of RC Dapped-End Beams

Abstract EN

Reinforced concrete dapped-end beams (RC-DEBs) are mainly used for precast element construction.

RC-DEBs generally are recessed at their end parts and supported by columns, cantilevers, inverted T-beams, or corbels.

The geometric discontinuity of dapped-end beams evokes a severe stress concentration at reentrant corners that may lead to shear failure.

Therefore, stress analysis is required at the reentrant vicinity for design requirement of these beams.

Four large-scale RC-DEBs specimens were prepared, cast, and tested up to failure.

Three parameters were investigated: amount of nib reinforcements, main flexural reinforcements, and concrete type at the dapped-end area.

Finite element analysis using Vec2 was also conducted to predict the behavior of RC-DEBs.

It has been found that highest stresses concentration factors occur at the reentrant corners and its vicinity.

By using engineered cementitious composite (ECC) in the dapped-end area, the failure load has increased by 51.9%, while the increment in the failure load was 62.2% and 46.7% as the amount of nib reinforcement and main flexural reinforcement increased, respectively.

In addition, Vec2 analysis has been found to provide better accuracy for predicting the failure load of RC-DEBs compared to other analysis approaches.