Concrete paving and bridge work on the Ambassador Bridge Gateway Project in Detroit has been proceeding. There is approximately 50,000 cubic yards of concrete being used for the bridge work on the project.
The fourth phase of the over $230-million project includes:
- The reconstruction of approximately 1-1/2 miles of main line paving on Interstate 75 from Rosa Parks Boulevard to Clark Street
- 1 mile of main line reconstruction on Interstate 96 from the Interstate 75/Interstate 96 interchange northward to Warren Avenue
- The reconstruction of 18 ramps and 24 bridges
- 3 miles of retaining wall along the reconstructed freeway
All roads are expected to be open to traffic in 2009. Landscaping and cleanup will continue in 2010.
A new cable-stay pedestrian bridge will have a cast-in-place concrete pylon that will rise over 100 feet in the air. A high performance substructure concrete mix that is 6,000 psi is being used on post-tension concrete for the center pylon and a few select pier caps on the pedestrian bridge. Typical substructure concrete is 3,500 psi, according to Bob Jones, vice president of Walter Toebe Construction Co. Located in Wixom, Walter Toebe Construction Co. is the prime contractor for the project. A type K concrete is also being used on superstructure in several different areas.
Jones said that the project includes constructing 30-foot-tall concrete walls that have large forming packages with unique texturing on each pour. He said that concrete form vibrators are being used on the project.
"Typically, we'll have the hand-held vibrators while we're pouring concrete. With some of the pours that we have specific to the pylon on the pedestrian bridge, we had to go with form shakers, just because it's very difficult to try to get the proper consolidation that is needed," Jones said. The form shakers attach to the outside of the form. They vibrate the entire steel form. The vibration penetrates 12 inches to 18 inches into the concrete pour, depending on the setting that it's on. Custom built forms are being used for the center pylon on the pedestrian bridge.
Approximately 320,000 square yards of concrete paving is being done on the project. The concrete pavement ranges from 10 inches thick to 13 inches thick, according to Marcus J. Navetta, P.E., project manager/estimator for Six-S Inc., of Waterford Township. Six-S is a subcontractor doing pavement removal, underground work, dirt work, and paving. Six-S is using a P-1 modified concrete pavement on the project.
"With any project that is this size and of this complexity, access points are a big challenge. There are a lot of people trying to utilize the same space. You must have a good plan so that you can get your trucks in and out and get concrete in front of the paver," Navetta said.
Navetta said that Six-S has a new dowel bar inserter for its GOMACO paving operation. "For access reasons, it allows us to dump concrete directly in front of the paver rather than having to use a spreader, MTP, or placing baskets as we go. Access-wise, it's helped us a lot," Navetta said. Navetta added that the dowel bar inserter provides more production and there are fewer breakdowns because there are fewer moving parts.