Design of Short Reinforced Concrete Bridge Columns Under Vehicle Collision

This paper presents the behavior of reinforced concrete bridge columns subjected to vehicle collision. An extensive parametric study consisting of 13 parameters was conducted, examining the peak dynamic force and the equivalent static force (ESF) of a vehicle collision with reinforced concrete bridge columns. The ESF was calculated by using the Eurocode approach and the approach of the peak of the 25-ms moving average of the dynamic impact force. The ESFs from these two approaches were compared with the AASHTO load and resistance factor design ESF of 2,670 kN (600 kips). This ESF was found to be nonconservative for some cases and too conservative for others. The AASHTO load and resistance factor design ESF was nonconservative when the vehicle’s velocity exceeded 120 km/h (75 mph) and when the vehicle’s mass exceeded 16 tons (30 kips). This paper presents the first equation that calculates a design impact force, which is a function of the vehicle’s mass and velocity. The equation covers a wide range of vehicle velocities, from 56 km/h (35 mph) to 160 km/h (100 mph), and a wide range of vehicle masses, from 2 tons (4.4 kips) to 40 tons (90 kips). This approach will allow departments of transportation to design different bridge columns for different highways depending on the anticipated truck loads and speeds collected from the survey of roadways. A simplified equation based on the Eurocode equation of the ESF is proposed. These equations do not require finite element analyses.