Giving reliable vertical support to your soft soil
Fort Belvoir Community Hospital
Fort Belvoir Community Hospital was built to provide medical care for wounded soldiers and their families. The $800 million, 1.3 million square foot military construction project would be managed by the Corps of Engineers with an aggressive schedule and would require ground improvement to support the five, multi-story adjoined buildings plus two parking garages. The challenge was its location: within three miles of the Fall Line, the boundary separating the Coastal Plain from the Piedmont Physiographic Province. The problem soils immediately below the surface from 7-12 feet were stiff to hard low plastic and high plastic clays with varying amounts of sand, underlain by dense sands and gravels.
Although initially planning to use rammed aggregate piers for the project, Menard USA needed to convince the Corps that Controlled Modulus Column (CMC) rigid inclusions were the ground improvement solution they were looking for to not only allow for faster installation to meet their deadlines, but also provide cost savings.
Menard’s ground improvement solutions increase the overall safety against bearing capacity failure, and provide control and differential settlement for the soil supporting your steel bottom, concrete bottom, concrete wall ring or gravel wall ring structure.
Convincing the Corps was no easy task. Since the Corps had designed spread footings for the project with a specified bearing capacity varying between 7,000 and 8,000 pounds per square foot, Menard went through a rigorous design process to demonstrate that the CMC rigid inclusions would work at the required high-bearing pressure and still meet the performance criteria for settlement. The design team then ran a series of proprietary Menard footing settlement calculation models and confirmed the analysis with a third-party review using a 3D finite element model.
Menard installed a dense array of CMC rigid inclusions under each foundation support, installing over 4,900 CMC rigid inclusions at a maximum depth of 29.5 feet for a total of 63,322 linear feet—including a load transfer platform to eliminate any physical connection between the ground improvement system and the structure.
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“Creative problem solving was our strength at hot and humid Fort Belvoir—even down to the decision to have a local ice cream truck visit our site daily.”
Todd Springer, Superintendent, Ft. Belvoir Project
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