Commercial Foundation Repair in MO & IL, including St. Louis, Springfield & Champaign.

Commercial Foundations Case Studies: STEAM Elementary in Hazelwood, MO

Thursday, July 13th, 2017 by Desiree Bainbridge

Challenge

The STEAM (Science, Technology, Engineering, Art and Math) Elementary School building, originally built in 1967, was planned to receive upgrades and renovations. This work would transfer an additional 103 kips of load to two interior column locations. Deep foundations were then considered to support this load and prevent removal of large areas of floor slabs around the columns in order to extend the existing spread footings. However, the school was originally constructed over an infilled lake, requiring that the deep foundations extend well below the old lake bottom to reach highly competent soils.

Solution

Helical piers with side-load retrofit brackets were selected to support the additional column loads. The helical piers consisted of the Model 350 (3.5-inch OD by 0.340-inch wall) round shaft with an 8”-10”-12” helix plate configuration. The piers were installed in a near-vertical orientation on opposing sides of each of the two columns (four piers total). The helical piers were advanced to depths from 77 to 84 feet below the footing to bear the helix plates below the old lake bottom elevation and to achieve torque-correlated ultimate capacities of at least 103 kips (FOS≥2). The retrofit brackets were set against the footing and the piers were loaded to the design working load of 51.5 kips and locked-off. Special care was taken to verify that no movement occurred at the columns during the loading process. The pier sections and bracket components were hot-dip galvanized for corrosion protection. The retrofit brackets and the top several inches of the piers were also cast in concrete. The four retrofit helical piers were installed in one day.

Project Summary

Structural Engineer: Kreher Engineering, Inc

Geotechnical Engineer: Geotechnology, Inc

General Contractor: R.G. Ross Construction Company

Primary Foreman: Jose Lorenzana

Commercial Accounts Specialist: Paul Brower

About the author
Desiree is a digital marketing coordinator at Woods Basement Systems.
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