Project
Sector – High School Gymnasium
Location – Onawa, IA
Application(s) – Vibratory Stone Columns (VSCs) / Aggregate Piers, Helical Piles

Description
A new gymnasium addition was being constructed on the campus of a high school. As the result of the soft, compressible soils conditions ground improvement was required for support of the gymnasium foundation walls.

Requirements & Challenges
As the result of low density soils falling within the foot print of the proposed structure, this provided concerns and the Engineer of Record specified the ground to be improved along the exterior strip footings.

Solution
Helitech installed new construction helical piles within 16 feet of the adjacent structure and monitored capacities by recording installation torque values during the pile installations. We conducted a full-scale load test to field verify the vibro stone column (VSC) loads and deflection. Helitech installed VSC’s along the exterior wall footings at various depths depending on in-situ soil strengths.

Results
Helitech completed the ground improvements in a couple of days. The tests performed extremely well and deflections were approximately 50% of the maximum deflection tolerances.

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