Hospital Office Building Settlement Solution

The Challenge

A hospital office building had experienced settlement across half of the building.

In Henderson, Tennessee, a hospital office building had experienced settlement across half of the building; about 160’ x 50’. The existing structure is supported by drilled shafts extending into solid rock. The slab, however, is supported by 30’ plus of backfill material. Consolidation of the backfill material had caused slab settlement and voids, creating trip hazards for patients and health care workers throughout the facility. With the safety of surrounding personnel compromised, Groundworks was called to rectify the settlement issue.

A local consulting firm completed a geotechnical exploration to evaluate the condition of underlying soils. The slab was cored in 12 locations to evaluate the subgrade soils. The study detected weak soils and several voids as large as 1.5” below the slab. Groundworks polyurethane injections were proposed for the project as a quick and effective way to stabilize the underlying soils while providing a lift to the settled slab.

Key Facts

The Solution

Groundworks polyurethane injections were used as a quick and effective solution.

For the slab settlement project in Henderson, polyurethane injections combined with Method was the ideal solution to lift the slab back to grade and stabilize the soils below. During the repairs, Groundworks crew performed the Method Process in a grid pattern across the compromised area. Polyurethane injections was used to stabilize and fill voids along an external grade beam. Crew members injected polyurethane injections into the subgrade soils according to a site-specific injection plan. This both stabilized the weak fill soils and filled all voids to ensure that the slab’s bearing capacity requirements were met.

The Impact

The operation was completed ahead of schedule and with no downtime for the tenants.

Polyurethane injections stabilized the slab, increased the compressive strength of the soils below, and improved safety of hospital personnel. The owner was pleased with the result. Settled slabs were lifted back to grade to alleviate tripping hazards. The repair was completed at night to avoid downtime for the tenants, and all flooring and furniture were left in place during the installation. The tenants were able to work during the day between the crews’ night shifts. Thanks to Groundworks, the operation was completed ahead of schedule and with no downtime for the tenants.