Rapid Impact Compaction – 1680 m²

This project consisted of the erection of falsework structures in order to build an overpass crossing
the realigned Riverside Drive in Ottawa, Ontario. Ground improvement was required in order to
compact the loose soils to improve the bearing capacity of the soil to allow for the placement of
preload, ultimately resulting in the erection of the falsework structure and the overpass
construction.

The soil in the working area consists of 1 to 4 meters of fill, typically garbage and other refuse material within a silty clay matrix. The general contractor excavated to a mutually established grade and placed a half-meter layer of sand which allowed for the Rapid Impact Compaction rig to travel on the platform as well providing for some replacement material to be pushed into the in-situ soils
enhancing their strength properties.

The objective of this work was to create 2m deep sand columns using the Rapid Impact Compaction (RIC) equipment. Phase 1 points were 5 meters apart on a square grid with Phase 2 points in between. Each phase was completed using 4 passes until a column of compacted sand was formed in the fill. During the work, a third phase was added to further compact the surface.

This solution was chosen to avoid a costly excavation and replacement method of work. In
performing the Rapid Impact Compaction work, Geopac delivered an efficient, cost-effective
solution that was well-suited to the project needs.