Project: Nashville City Center parking garage - Nashville, TN
Customer: City of Nashville, TN
Contractor: R.C. Matthews Contractor - Nashville, TN
Finisher: Charter Construction - Nashville, TN
Project obstacles and solutions: The Nashville City Center parking garage is a six-level underground facility that adds space for 420 vehicles in Nashville's downtown area. The concrete specs for the cast-in-place columns called for a 10,000 psi post-tension mix. The concrete for these columns were to contain silica fume (microsilica), which is used as a pozzolan binder in place of cement especially where high strengths are desired.
A major concern was the columns were scheduled to be poured in August when daytime ambient temperatures were in the 90s. Any cementitious material heats up when it mixes with water. The specs called for strengths to be achieved in a short period of time, with tests performed at 24 hours, 3 days and 5 days. For this to happen, the concrete needed to be delivered below 90 degrees F. This would allow the hydration of the cementitious materials to happen without high heat and allow the concrete to gain early strength. IMI QC/QA personnel added ice to the mix and dosed admixtures at the job site to keep the concrete temperatures in check.
Along with the heat issues, the schedule called for the columns to be poured at the same time that the decks were being poured. The concrete for the high-strength columns were delivered by bucket while the concrete for the decking was being pumped onto the site. The IMI Nashville Concrete Plant supplied 500 yards of high performance concrete for the columns without any delays in delivery.
The City Center parking garage is set to open in January 2014.