Parking Structure Project Proceeds
A new 4,800-vehicle four-level parking structure, site work and a grand canopy entry area are currently under construction at the Gerald R. Ford International Airport in the Grand Rapids area. The approximately $115-million project began in September 2007 and it is expected to be completed in October 2009.
"This is a phased project over a two-year period. The first year of the project includes building the grand canopy. By the end of this year, we'll open a new road, the canopy structure will be done, and we'll have approximately 60 percent of the garage built, but it won't be open until we finish the second portion of the garage," said Scott J. Jones, vice president of The Christman Company, the project's general contractor. CCI/GRC (Christman Constructors Inc. and Grand River Construction) is the joint venture providing structural concrete for the project.
The 5,000-psi concrete mix design for the parking structure includes Portland Cement, ground granulated blast furnace slag and fly ash. Approximately 70,000 cubic yards of concrete is being placed on the project. The concrete mix has a corrosion inhibitor in it.
"We're maintaining the best possible water-cement ratio. The mix is hardening too fast. It's normal on a project like this to have several pours until you understand how the concrete needs to be batched, how many workers you need and how many trucks per hour are needed. We're working through that process now. We're making adjustments with how we pump, place and finish the concrete. We're being very careful with the amount of moisture in the aggregate," Doug Peters, P.E., project manager of the CCI/GRC Joint Venture, said.
Symons Corporation is supplying the garage beam formwork system, and the Engineered Products Group of Jobsite Supply, of Indianapolis, Ind., has done the concrete formwork for portions of the project including a radius wall and helix for the parking deck. The center parking deck retaining wall, which provides grade separation on the west side of the deck, runs in a continuous curved form for approximately 700 feet and contains a specific tie and reveal design that must be made uniform throughout the structure. Jobsite Supply showed its client CCI/GRC that it could design, build and furnish a system that was custom built for the job.
"We had to build panels that would not only curve, but would start and stop and finish on construction joints in accordance with the architectural drawing. We couldn't just start setting up forms and pour and break them where we want. This had to be a custom form," Tom Hotwagner, president of Jobsite Supply said.
"We take the design of the structure and we create the formwork design. Once the design is accepted, we build the forms so that they are ready for use. On this job we used a seven-ply Douglas fir plywood that has a medium density overlay, which is a flat stucco look. It imparts what we call a matte finish. We did a special address for the ties, which hold the forms together. For zero seepage, we had zero tolerance on the wall ties. Those ties go through the form at the same diameter as the steel tie itself. We usually over-drill the tie holes so that there is a little bit of flexibility. You can push it in there and wiggle it to where you need it. They didn't want any seepage coming out of the form face."
Hotwagner said that Jobsite Supply will be doing the poured-in-place concrete helix, a circular ramp that will come off of the parking deck. "It's probably one of the most difficult concrete things to pour," Hotwagner said.
"The toughest part of this project is working around this busy environment. Traffic control and getting pedestrians in and out of the terminal safely is a continuous challenge. We lift the trusses at night, when airport activity is at a minimum, and utilize temporary lighting that does not interfere with the air traffic, which is a challenge in itself," Jones pointed out. Jones said that truss work has gone smoothly.
CCI/GRC is doing the concrete work on the project. Subcontractors on the project include Sci-Steelcon, of Kalamazoo (steel for the canopy) and SS&E, of Grand Rapids (miscellaneous steel). Gresham Smith and Partners, of Dallas, Texas, is the architectural, civil, mechanical, and electrical engineer, and the engineering subcontractor for the parking deck is Carl Walker, Inc., of Kalamazoo. JJR Ann Arbor is the landscaping designer.