Effectiveness of CFRP shear-strengthening on vehicular impact resistance of double-column RC bridge pier

Abstract

As-built reinforced concrete (RC) piers could be subjected to vehicular collisions in their whole service life, resulting in severe shear failure of piers and even catastrophic damage to entire bridges. Considering that the vehicular collision is the lateral consecutive impact process including bumper, engine and cargo impacts, the effectiveness of CFRP shear-strengthening of double-column RC bridge piers (DCBPs) to resist the lateral consecutive impact needs to deeply studied. Firstly, the reduce-scaled vehicle model lateral consecutive impact test is performed on a bare pier, a CFRP shear-strengthened slight-damaged pier and a CFRP shear-strengthened intact pier in DCBP specimens. The influence of CFRP strengthening on the damage evolution, failure mode and transient dynamic responses and energy dissipation are examined. Then, numerical simulations of the present impact tests are conducted to validate the adopted finite element analyses (FEA) approach. Furthermore, based on the validated FEA approach, a local refined finite element (FE) model of a prototype simply-supported two-span double-column RC bridge is established, and six numerical simulations of typical light, medium and heavy trucks colliding with the entire bridge with/without CFRP strengthened pier are performed. Based on the simulated results, the effectiveness of CFRP strengthening on the dynamic shear demand, dynamic bending moment and deformation of the impacted pier, as well as the damage/failure and collapse of the entire bridge are further evaluated and discussed. It is found that: (i) compared with brittle shear failure of the bare pier, the strengthened slight-damaged and intact piers both have the excellent lateral consecutive impact resistance with exhibiting shear-flexural and ductile flexural failure modes, respectively; (ii) suppression of the shear damage evolution is beneficial to both strengthened slight-damaged and intact piers to have the higher damage and defamation tolerance to dissipate more impact energy; (iii) the strengthened intact piers in the prototype bridge model can withstand the higher dynamic shear demand and dynamic bending moment but experience the less deformation and damage; (iv) since the deformation and damage of strengthened intact pier in the prototype bridge model under actual vehicular collision are significantly reduced, the vehicular impact resistance and collapse resistance of entire bridge can be improved.