The surface layers at the site consisted primarily of silt with varying amounts of sand and clay. Beneath these layers, at a 30-ft depth, the material changed to clayey silt and silt with fine sand. The profile varied across the site.
Menard’s design was based on two working pads to accommodate varying elevations in the finished floor. An upper-bench pad was used for the tornado shelter; a lower-bench pad for the library. This ensured work would be done in one continuous phase without the need for remobilization. Menard worked closely with the structural engineer in designing a CMC layout at each footing to support column loads, while also designing the elements along the wall and slab for additional support. Menard installed approximately 300 CMCS to a maximum depth of 30 ft. The design provided for 1 in of post-construction settlement with a ½ in of differential settlement, meeting the performance criteria of the new addition.
A challenge during the project was the presence of heavy storms. This necessitated additional support to the working pad via undercutting/gravel fill. Another challenge: The CMCs supporting the deep tornado shelter footings in the upper bench hit refusal at shallower depths than bottom-of-footing elevation. Consequently, Menard predrilled across the upper pad to determine drill depths. Despite these challenges, Menard met the owner’s requirements for quality, safety and schedule.
Menard successfully installed CMCs to support a new library and tornado shelter for the 8,500 sq-ft addition at Fairview High School in Erie County. The project was completed within schedule and budget and met the settlement requirements established in the performance specification.