YMCA of Northwest Florida
The Problem:
The YMCA of Northwest Florida had plans to construct a new state of the art facility to replace its existing facility in Pensacola, FL. The new 52,000 square foot building was to contain an indoor, accessible aquatic center with two pools. Plans called for the building and pool foundations to be supported by auger cast piles. The key to the project schedule would be installing the roof system as quickly as possible so that the building would be dried in so that weather could no longer affect the production schedule. In order for this to be accomplished the deep foundations for the pools would need to be installed after the roof was complete. The general contractor, Greenhut Construction, also wanted to perform the pool excavations after the roof was installed to decrease the de-watering period for the pool area, and so that the building would not have to be constructed around the excavation. Greenhut estimated that this would save approximately six (6) weeks of production time. To accomplish this, a high capacity deep foundation was needed that could be installed indoors in a limited access area.
The Solution:
The CHANCE Helical Pulldown Micropile (HPM) system was the perfect fit for this scenario. HUBBELL/ CHANCE is the world's leading manufacturer of helical foundation systems. Backed by more than 100 years of engineering experience, the HPM is a technologically advanced, cost-effective, high capacity deep foundation system. The HPM is a true composite pile that combines both skin friction and end bearing components to provide much higher capacities than those provided by standard helical piles. To view a load test database, please visit the Helical Pile Association at loadtest.helicalpileassociation.com.
Technical Description
Product:
The pools were supported by a total of (36) Helical Pulldown Micropiles. Working loads per pile ranged from 65 to 100 kips in compression and 10 to 65 kips in tension. Pile depths ranged from 50 to 70 feet in length. Each pile was equipped with a 10” square new construction plate to allow for connection to the new poured concrete footings. Lead sections consisted of an 8710712714" helix configuration on an SS225 shaft (2-1/4” square). The grout column was 7" in diameter and provided an additional 3,000 lbs. of capacity per linear foot of grout column. A load test was conducted prior to production pile installation to verify the additional load that would be achieved by the grout column. All piles were installed to meet the design loads with a minimum factor of safety of two (2). Pile installation was completed in one (1) 40 hour workweek.