| This dissertation presents a step by step procedure to predict the response of a concrete barrier subjected to vehicular impact. Additionally, the soil is to be assessed using dynamic analysis. The objective of the dynamic analysis was to ensure that the displacement of the barrier during an impact is within safe limits. This can be determined by calculating the forces and moments which are transmitted to the subsoils and comparing them with the dynamic soil resistance's and allowable bearing capacities of the supporting soils.;The Linear Elastic Weightless Spring Method was used to develop and formulate the equations of motion. This method uses a system of lumped masses, springs and dashpots to model the actual soil-barrier system. Equivalent coefficients of soil reaction were obtained from current literature to include the embedment effect. The barrier is treated as a surface foundation and the coefficients of soil reaction obtained are replaced with equivalent coefficients which include embedment effect.;Five impact loading cases were considered and analyzed. The forcing functions representing the impact loads were modeled as sine and rectangular pulses for head-on and oblique impact. The angles of impact analyzed were 15, 30, and 45 degrees. The vibration modes induced by the impact loads are coupled sliding and rocking (head-on case), and two coupled sliding and rocking modes (oblique case). Computer programs were developed to solve the equations of motion for impulse type excitations for various vibration modes.;The results of the investigation for all modes of vibration appeared to be consistent. The presence of damping in the systems reduced the amplitudes of vibration and had no or little effect on natural frequencies. Damping in rocking vibration was negligible. The sine pulse produced higher amplitudes of vibration than the rectangular pulse. In conclusion, the soils supporting the barrier are strong enough to withstand the impact loads for the various loading cases considered in this research. |
