Search

Highway bridge piers could be underdesigned for a multihazardous condition involving vehicle collision and air blast based on the current design code. The piers are often positioned in such a fashion that it is neither possible nor economically feasible to place protective devices around them. This paper numerically investigated two potential strengthening techniques, the placement of a fiber-reinforced polymer (FRP) wrap and polyurea coating onto the column surface, to improve column resistance against the extreme demands from combined collision and blast loads. Finite-element models of isolated reinforced concrete (RC) columns with an FRP wrap and polyurea coating were developed using a commercial software, LS-DYNA. The modeling techniques were validated separately against impact and blast experimental results. Collisions were supplied from a medium-size F800 single-unit truck at various velocities, and air blasts of varying magnitude were represented using the arbitrary Lagrangian–Eulerian approach. Bare and strengthened column response to various collision and blast demands was compared to assess the effectiveness of strengthening. The results indicated that using the FRP wrap and polyurea coating on columns could effectively mitigate the effects of combined vehicle collision and air blast. The effectiveness of each scheme differed as a function of geometric and material properties and column demands. Parametric studies were then conducted to evaluate the influences of various design parameters on column performance and identify optimal strengthening schemes. [ABSTRACT FROM AUTHOR]

The extreme multihazardous event involving a truck collision and an air blast is a low-probability, high-consequence event for bridge piers. This study aimed to numerically investigate the performance and failure modes of multicolumn piers under a medium-sized truck collision combined with an air blast. Full-scale, finite-element models of multicolumn piers with three configurations were developed using LS-DYNA software with a soil domain restraining the foundations. The accuracy of modeling approaches was verified by comparing tested and simulated results. The collisions were simulated using a single-unit truck (SUT) at velocities ranging from 65 km/h to 120 km/h and combined with air blasts at different scaled distances. Analyses were completed to examine damage propagation and dynamic response during the extreme multihazards. The results showed that after the SUT collision compromised pier capacity, further deterioration occurred from the subsequent air blast, resulting in severe damage and even failure of the pier. In addition, parametric studies were conducted to assess the effects of several load and design parameters on pier performance and identify the controlling parameters. Representative failure modes of multicolumn piers under truck collisions combined with air blasts were assessed. The findings from this study provided a comprehensive understanding of multicolumn pier response to the extreme multihazards and developed recommendations for the practical design and analysis of the multicolumn pier. [ABSTRACT FROM AUTHOR]