Medical Clinic Emergency Foundation Repair at US Air Force Academy

The Challenge

Voids averaging 3 inches discovered beneath slab.

At the U.S. Air Force Academy (USAFA) in Colorado Springs, the 10th Medical Group (10th MDG) conducts operations from a dual-purpose facility, with a clinic and surgical center on the ground floor and administrative headquarters upstairs. In early 2020, the ground floor at the 10th MDG facility was undergoing a renovation project. While trenching the foundation to add electrical and mechanical connections, workers discovered many voids, averaging three inches, beneath the slab. Additionally, an inspection of the operating room floor revealed cracking, shifting, and early signs of slab failure. The prime contractor for the project, Gilbane Federal, understood that closing the medical clinic to remove the current slab, repair the subbase soils, pour a new concrete floor, then continue on with the original project would be expensive both fiscally and operationally for the 10th MDG. Looking for a better solution, Gilbane Federal turned to Groundworks.

Key Facts

The Solution

Stabilize the foundation, fill all identified voids, and mitigate additional stresses on the foundation.

Even though the Academy was under COVID-19 restrictions at the time, Gilbane Federal asked Groundworks to conduct a site visit, provide an analysis, and offer a solution. A Ground Penetrating Radar (GPR) survey confirmed the location and depth of the numerous voids beneath the slab. These voids were determined to be primary cause of the cracking and shifting in the slab. Groundworks proposed a void-filling application using Groundworks polyurethane injection to stabilize the foundation, fill all identified voids, and mitigate additional stresses on the foundation. Groundworks’ plan was accepted over competing alternatives, providing the best cost, schedule, and performance options.

For this project, Groundworks was required to initiate and complete the job within a week after award notification, with all work to be performed over a single weekend. Groundworks selected a crew highly trained in foundation repair and diverted them from New Mexico, where they were normally based. The crew arrived at the USAFA to begin work on Saturday morning at 0600 hrs. Following an initial safety briefing and Pre-Conmeeting, the Groundworks crew began work according to a site-specific injection plan based on the GPR survey results. On Sunday afternoon, all work was completed and inspected by Gilbane Federal, and the crew departed the academy.

The Impact

Building foundation slab was stabilized in 2 days.

In just two days, the 10th MDG building foundation slab was stabilized, with all voids filled and the subbase soils strengthened for long-term reliability. The prime contractor was able to continue work on Monday as scheduled, without any negative impact on the project critical path timeline.

Groundworks delivered “Mission Completion” within 28 days of initial contact, under difficult and extraordinary circumstances. The flexibility and capabilities of Groundworks were highlighted by the limitations under which the crew operated.

1. The completion timeframe for the project was just two days, restricted to a specific weekend.
2. Operations were conducted during a worldwide pandemic, in compliance with various national, federal reservation, and state restrictions.
3. Academy entrance restrictions, searches, and individual background checks were conducted for crew members.
4. Secret Service restrictions were also in effect, as graduation weekend at the academy was underway and the Vice President of the USA was present for the commencement ceremony.