Harbour View Haven Addition & Renovation, Lunenburg, NS

THE PROBLEM

The main geotechnical concern for the new proposed development was the presence of a relatively thick layer of uncontrolled, fine grained fill covering the site. These materials were up to 14 feet thick and deemed unsuitable for supporting the new footings and floor slabs of the proposed expansion. The Geotechnical Engineer recommended that all fill material be removed and replaced within the building footprint with compacted structural fill. The high cost of excavation and disposal of materials, dewatering of the site, stabilizing the excavation and replacement with structural fill created high costs that encouraged the  owner to seek an alternative solution.

THE SOLUTION

The Geopier® Rammed Aggregate Pier Intermediate Foundation System was chosen as an alternate solution to over-excavation and replacement. The choice  resulted in a savings over replacement of approximately 25% and accelerated the construction schedule due to the speed of installation in any weather.

This unique installation process involved pre-augering 30-inch diameter holes through the fill and ramming 12-inch thick lifts of well graded aggregate with a beveled tamper to form very stiff, high-density  aggregate piers. The ramming action both densifies the aggregate and forces the aggregate laterally into the side walls of the hole, significantly strengthening and stiffening the subsurface soils, that then can  support traditional spread footings and unreinforced  slabs on grade.

Geopier® Rammed Aggregate Piers exhibit  unsurpassed strength and stiffness which reinforces  poor soils  thus increasing its bearing capacity and provides total and differential settlement control within  acceptable standards.