Music City Concrete

“That floor really ate up the concrete and rebar,” Brazzale explains. “Fifth floor pours on Building A averaged 10,000 square feet each and required 600 cubic yards of concrete, and we poured one every five days. These pours were primarily placed by crane and bucket, and usually started at 9 p.m. to reduce impact to the community. We ran two and a half shifts of crane operators just to keep up. Running concurrently with this was the fourth floor ahead of us and the second and third floors in Building B. Our rebar and concrete suppliers were stretched to the limit to keep up, and somehow managed to make it all work.

“At one point in mid-October of 2010 between weather delays I remember starting a third floor pour at 4 a.m. on a Wednesday and pouring concrete continuously in one place or another by one means or another until 5 p.m. on Saturday afternoon. Metro Ready Mix delivered concrete to us for 85 hours straight. When the dust cleared we had placed just over 3,000 cubic yards of concrete over 89,900 square feet of flatwork — and this total doesn’t even count quantities for vertical work or foundations, where we were also active at this time. During peak production, things got pretty crazy out there,” Brazzale adds.

Concrete planning

The 110,000 cubic yards of concrete required of Music City Center is twice the total used to build LP Field, home of the National Football League’s Tennessee Titans. During peak months of construction Ceco was installing up to 13,000 cubic yards of concrete and 1,800 tons of rebar per month. To complete the structural concrete scope of the project, Ceco supplied a total of 150,000 square feet of forming material and installed it with the help of up to six tower cranes at a rate of just over 10,000 square feet per day. One of the keys to the project team’s ability to deliver this magnitude of work at such a rapid pace was the early involvement of subcontractors like Ceco in design development. Having built 37 convention facilities in the past 10 years, Ceco’s design assistance was valuable.

Drawings were 50 percent complete when Ceco was awarded the project, allowing Ceco to team with Bell/Clark and the design group to flesh out drawing conflicts through constructability review and provide value engineering solutions to keep the project on track and within budget. One of the first opportunities to do so came in the form of “mud cutters” — unstable seams of mud running through limestone that appeared under most of the six-block site that had to be cleaned out and repaired. In order to mediate the problem Ceco developed a “hole card” and worked with Bell/Clark and the structural engineer to develop a procedure that allowed the project to continue moving forward. The hole card documented deviations from original plans and set the parameters for the revised design details of the footings, columns and closure slabs as Ceco progressed, keeping the project on schedule. According to Bob Borello, Clark Construction, the early involvement of all players was critical to the success of the project to date.

“Early involvement by the Ceco team helped us develop site logistics planning, trade coordination and scheduling, and our process of reviewing shop drawings and submittals with the structural engineer,” Borello explains.

Another benefit of early and regular meetings of the project team was the efficiency of targeting LEED Silver certification. One of the most notable sustainable aspects of the project is a 175,000 square-foot green roof designed to mimic the rolling hills of Tennessee.

Overcoming challenges

Minimizing the project’s impact on the public was another key goal of the project team. This required attention to detail and sequencing, and at times herding elephants — literally. When concerts, performances or national music awards were held in Nashville, they were held in the Sommet Center/Bridgestone Arena across the street. All performers and their stage gear had to be delivered through the project site to access an underground tunnel to the arena. This even included a parade of elephants when the circus came to town.

“We joke that every day here is a circus, but on January 21, Ringling Brothers Circus came to town and their normal route to access Bridgestone Arena was closed due to construction,” explains Holly McCall with the Nashville Convention Center Authority. “The elephants were rerouted and came into their temporary home under the arena by accessing the site at the corner of 5th Avenue and Demonbreun Street, on the northeast corner of the site. It didn’t slow work a lot that day, although most of the folks here said it’s the first project on which they’ve worked that elephants came on the site.”