Evaluating impact loading from a heavy vehicle collision against safety parapet integrated with retaining wall

Retaining walls are used to retain soil and create a separation in elevation between two areas of the road and highway network. To keep vehicular traffic on the elevated side safe from falling over, safety parapet barriers would be erected at the top of the wall. In the event a heavy vehicle collides against the parapet barrier, the impact loading may destabilise the retaining wall. The load dispersal is quite complex, and engineers often grapple with finding a practical and reasonable way of incorporating it as a pseudo-static live loading in the design of the retaining wall. Current literature on the loading distribution useful for geotechnical stability design seems to be lacking. This paper discusses an approach using finite element simulations to develop better insights of the complex impact loading issues. The simulation results are used to develop an equivalent 2D plane-strain pseudo-static loading to the impact loading by taking geotechnical stability into consideration. This approach is applied to a 1-m and a 3-m high retaining wall (both with a 1.2 m high parapet barrier integrated at the top) to serve as illustrative examples.