Ultimate Shear of RC Beams with Corroded Stirrups and Strengthened with FRP

Nino Spinella,Antonino Recupero,Francesco Tondolo,Piero Colajanni

doi:10.3390/buildings9020034

Nino Spinella, Antonino Recupero + Show 2 more

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https://doi.org/10.3390/buildings9020034

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Abstract

Transverse reinforcement plays a key role in the response behavior of reinforced concrete beams. Therefore, corrosion of steel stirrups may change the failure mode of elements from bending to shear, leading to a brittle and catastrophic crisis. It is important to strengthen reinforced concrete beams with corroded stirrups to enhance the shear resistance. This paper presents a formulation, based on the modified compression field theory, to estimate the ultimate shear of reinforced concrete beams strengthened with FRP, because of stirrup corrosion. The detrimental effect of corrosion on steel stirrup yield strength was taken into account by introducing an empirical decay law. The effective strain of FRP reinforcement was adequately evaluated by considering both debonding and tensile stress rupture. The proposed model was validated against collected experimental results, showing a good ability to evaluate shear strength. Moreover, a numerical analysis was carried out to highlight the role of the key parameters predicting the ultimate shear.

Highlights

The decay of structural performance occurs in many existing reinforced concrete (RC) structures due to reinforcement corrosion
Stirrup corrosion is strictly related to concrete cover cracking
This research work aims to contribute to an understanding of the shear failure mechanism of RC beams with corroded stirrups and strengthened in shear with FRP sheets

Summary

Introduction

The decay of structural performance occurs in many existing reinforced concrete (RC) structures due to reinforcement corrosion It leads to the loss of the cross-sectional area of the steel bars, cracking of the concrete cover, and a damaging effect on the bond between steel bars and concrete [1,2,3,4,5]. To avoid this, retrofitting of structures is necessary in order to ensure the safety and serviceability of RC structures damaged by corrosion [6,7,8,9]. The start of cracking of the concrete cover, related to the increase in the degree of stirrup corrosion, leads to a proportional decay of the shear strength of the RC beam

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