135 / 2022-04-28 21:47:08

Experimental and numerical investigation on the dynamic behavior of RC bridge columns confined with CFRP/ECC subjected to truck collision

Reinforced Concrete Column; CFRP grid; ECC; Impact Response; Truck-bridge Collision

Reinforced concrete (RC) bridge columns are susceptible to vehicle collisions. To enhance the impact resistance of RC bridge piers, a composite material composed by Carbon Fiber Reinforced Polymer (CFRP) grid and Engineered Cementitious Composites (ECC) is employed to strengthen RC column. Laboratory tests on cantilever RC column and CFRP/ECC confined RC column subjected to lateral horizontal impact are carried out. Test results showed that CFRP/ECC has a significant effect in limiting the development of shear cracks and improving the shear capacity of RC column (Fig. 1).



Detailed finite element (FE) model of the laboratory tests is established and the response CFRP/ECC confined column under impact loading is predicted with the FE model. Numerical results indicated that the impact force, displacement and failure mode of CFRP/ECC confined column could be well predicted by the finite element model (Fig. 2). Furthermore, ECC confined columns were prone to shear failure, while CFRP/ECC confined columns are more likely to suffer an overall failure at the footing of the column.



With the validated FE method, high-resolution FE model of truck-bridge collision scenarios are established. Numerical analysis is carried out to compare post-impact damage of RC column and column confined with CFRP/ECC. The results demonstrate that CFRP/ECC has a significant effect on decreasing the tension stress of longitudinal reinforcements (Fig. 3) and reduce the damage level caused by flexural and shear cracks (Fig. 4). Moreover, CFRP grid and ECC has a significant influence on the dynamic shear capacity of columns, while weight of engine and impact velocity of truck are the key factors that affecting the dynamic shear demand. Finally, empirical equations for calculating dynamic shear capacity and shear demand of CFRP/ECC confined RC piers subjected to truck collision are proposed and the shear mechanism of confined piers is also clarified.