Batson-Cook Construction

Tower of Wachovia┬áBatson-CookÔÇÖs construction of a 48-story office building for Wachovia Corporation overcame a number of challenges. April Terreri has the story. When the Wachovia First Street Office Tower project is complete early next year, it will be an example of a LEED-certified Gold building and one of the tallest and most design-innovative buildings in Charlotte, North Carolina.  Contractor Batson-Cook Construction began work on the $450 million building in 2006 and surmounted numerous challenges along the wayÔÇöone of which was blasting through 50 feet of solid rock.The 1.5-million-square-foot Wachovia Office Tower sits atop an eight-level underground parking deck on a full city block in Charlotte. ItÔÇÖs part of a mixed-use city campus, which will also include art museums, a 1,200-seat performing arts theater, an African-American Cultural Center and a plaza.ÔÇ£This was a community-focused effort for so long,ÔÇØ says Curt Radkin, WachoviaÔÇÖs senior vice president and one of the development managers for the project. ÔÇ£The cultural groups involved in the campus have been trying independently to push their respective programs. But it was the vision of our president, Bob Bertges, who developed the idea of constructing a building whose generated property taxes could help fund these arts facilities.ÔÇØThe Wachovia Tower construction project was a collaborative effort from the start among a number of players, notes Randy Thompson, vice president and project executive of the Atlanta office of Batson-Cook, with headquarters in West Point, Georgia. He credits the companyÔÇÖs strong long-term relationships with Wachovia and Childress Klein Properties (the fee developer for this project).Before construction on the building could even begin, Batson-Cook had to excavate down 80 feet to accommodate the underground parking deck and a loading dock. ÔÇ£Fifty of those 80 feet were solid rock, which we had to blast,ÔÇØ reports Thompson. ÔÇ£It took us about a year and a half to excavate the area completely. That was a big challenge.ÔÇØSo how did they manage this right in the middle of downtown Charlotte? ÔÇ£Well, it was noisy,ÔÇØ continues Thompson. ÔÇ£Every day at 3:30 pm we would blast the rock. People in adjacent office buildings and from the Charlotte Observer across the street would come and watch us blast.ÔÇØ He notes that this kind of excavation is unusual and expensive. ÔÇ£Most people canÔÇÖt afford the cost of this. But because of all the arts facilities and WachoviaÔÇÖs commitment to provide a quality and aesthetic campus, it decided to pay the price of putting the parking underground. Wachovia wanted to assure that the project would be aesthetically pleasing while meeting all the needs of the different cultural organizations in the campus.ÔÇØBatson-Cook had to build a temporary bridge for one of the cityÔÇÖs main streets to carry traffic while excavation of the tunnel to the loading dock and underground garage progressed. Pedestrian tunnels underground connect to all the campus buildings aboveground.The eight-level parking garage comprises about a million square feet of underground structure and has 2,200 parking spaces. The Wachovia Tower sits on top, sharing the area with the Mint Museum and to-be-built condo towers. The first seven levels of the building, each 50,000 square feet, were designed specifically to house WachoviaÔÇÖs commercial investment banking operations. The eighth floor houses an extensive data infrastructure to support the bankÔÇÖs trading operations.ÔÇ£At the tenth level, the footprint of the tower reduces to 25,000 square feet per level, up to the 42nd floor,ÔÇØ explains Thompson. At that level, the building begins to slope from two opposite corners of the building, looking somewhat like a crystal, and a sloped glass roof covers the top six floors. ÔÇ£It has a very striking appearance, with a 30 foot tall structural steel truss covered with metal panels running diagonally from corner to corner of the tower, located 70 feet above the tower roof.ÔÇØThompson says that the structural design for the tower is a tube frame with reinforced cast-in-place concrete columns and beams at the perimeter, and a cast-in-place core with precast double tees spanning from the perimeter to the core, eliminating the need for shear walls. This design offers a cost-effective solution, saving millions of dollars over using other construction methods. From the 42nd level to the top of the building, the core of the building, housing elevators, mechanical rooms, restrooms, electrical distribution, ventilation shafts and stairway, remains cast-in-place reinforced concrete while the remaining structure is constructed of structural steel and metal deck with concrete fill.ÔÇ£The precast double tees were cast in a facility offsite, and when they were brought onsite they were lifted up with cranes and set between the core and perimeter columns and beams,ÔÇØ explains Thompson.ÔÇ£We used a cast-in-place core and perimeter and then used double-tees to create the floor slabs outside of the core, which is unusual for a high rise building,ÔÇØ he continues. ÔÇ£This automatically gave us a new floor slab every four working days. Then we poured a concrete topping on that. This building is without question the tallest building that has used precast components like this in the US.ÔÇØ Because the building is so big, it was designed to keep the columns smaller, and Batson-Cook asked a local concrete companyÔÇöConcrete Supply CompanyÔÇöto develop a higher-strength concrete. Normally, high-rise concrete buildings use 12,000-psi concrete, but Concrete Supply was able to develop an 18,000-psi concrete for most of the vertical construction.For such a large project involving so many different stakeholders, the cooperation has been ideal, reports Thompson. ÔÇ£We all maintained a unified approach, and there was lots of collaboration among the cultural groups, Wachovia, the architects and engineers to develop a concept that everyone could agree with.ÔÇØWachoviaÔÇÖs Radkin agrees. ÔÇ£This was Bob BertgesÔÇÖ concept from the beginning. There are so many stakeholders, each with a different agenda. Bob knew from the start that the only way we could pull this off was for Wachovia to control the construction.┬áEveryone initially wanted to be on the corner of First Street and Tryon Street, and as a result of thoughtful planning, no one is on that corner. Instead, we have a beautiful plaza that all the stakeholders can enjoy.ÔÇØMinority participation was also an important goal for Wachovia. ÔÇ£They wanted minority firms to have the opportunity to provide goods and services to the bank, setting a minimum goal of 20 percent, which every facility has met or exceeded,ÔÇØ explains Thompson.Wachovia Office Tower should achieve LEED Gold certification, at a minimum. ÔÇ£Wachovia made a commitment to be a strong advocate for green construction, and early on they employed a consultant to assist in the process,ÔÇØ Thompson says, crediting Bertges with this commitment. Radkin adds that LEED certification is an important part of this journey. ÔÇ£RandyÔÇÖs team did an awesome job on the construction-related credits of the core and shell, and 23 points were wrapped up there,ÔÇØ he says. ÔÇ£We feel we are solidly in the Gold category.ÔÇØ┬áÔÇô Editorial research by Dan Finn┬á