Job Goes According to Form
September 2008This method for keeping crew size low while staying right on schedule was music to this builder’s ears.
The Rhythm @ Music Row, a downtown condominium complex, will be an important development for Nashville, Tennessee. The 250,000-square-foot, 15-story building, situated at the end of Music Row, will have retail and office spaces on the ground floor. The building’s unique design features a parking garage on the first five levels, above the retail stores, with the 10-story, 110-unit housing complex set back on the roof of the parking garage. To help build the structure as quickly as possible, the contractor, Harcon Inc., used 15,000 square feet of tables and in-fill, a Doka Table Lifting System (TLS), and shifting trolleys for quick cycling of the tables. For the ramps in the parking deck, the builder used stick building, a common method for that type of project.
To stay on the timeline for the project, the builders made a pour every 8 days once they got typical (in six levels). They poured at night, so that the next morning they could work on the vertical aspect of the job.
There was little room in and around the jobsite to store materials. The site was just 9 inches away from an Enterprise Rent-a-Car; the workers could literally reach out and touch that building. On another side, the site was 10 feet off the busy Demumbreun St., and there was a parking area for a business on another side. There was an alley that ran right beside the building in the back of the site.
“This was one of the tightest jobs I’ve ever been on in my life,” says Bobby Kay, project superintendent. They had just enough room to back an 18-wheeler in on Demumbreun St. They set the crane up there to go straight up, and they had to schedule every truck so that it could go directly into the building—there was no lay-down area.
“Being tight is one thing, but when you’re working above businesses that are open, that’s the hard part,” notes Kay. “You can’t lose anything off the building.”
From Formwork to Finish
According to Paul Campbell, Doka’s account manager for Rhythm @ Music Row, because the footprint of the building was so close to the actual size of the parcel of land, the contractor was constricted as to the type of construction methods that could be used to build the structure.
Originally, Harcon had decided to use conventional wood shoring as a method for construction. Although this method would fit the tight job constraints, it was time and labor intensive. With conventional wood shoring, all formwork is set up by hand and after the concrete is poured, the formwork is wrecked out by hand and moved to the next floor for hand set-up again.
What Harcon needed was a way to meet its schedule and keep its work force as low as possible. The answer was using Dokamatic tables and the Doka TLS. A typical table size is only 9 feet wide by 18 feet long, and the tables are delivered to the construction jobsite completely assembled, including plywood. This eliminates build-up cost, reduces rental costs, and allows for smaller crew sizes—exactly what was required to economically construct this building.
The tables allow for quicker cycle time and are ideal for fast formwork handling when casting large floor slabs. Fully assembled tableform units quickly position into place and eliminate the need for labor-intensive carrying of individual components from one location to the next. The TLS lifts the tables from one level to the next without using a crane. This frees up the site crane for other jobs, so the overall work at the construction site progresses much faster.
The TLS works kind of like an elevator that hangs off the side of the building. Once it is set in place, the crew can move all of the material up using the apparatus. It takes material to the next level with the punch of a button and then turns itself off automatically when it has reached that level. Once the material is moved off it, the crew simply presses a button, and it goes back down to the lower floor, where they can load more material on it for the next trip. It is a very efficient way to move material.
Harcon used an average 25 workers on the Rhythm @ Music Row project. The typical schedule for the project begins with a concrete pour at night, usually from 6 to 11 p.m. The rest of the schedule for the project goes something like this:
- Day 1: The crew forms and pours 14 columns. They also form and pour Stair 2 and the elevator.
- Day 2: The crew strips all of the form from the previous day, and forms and pours 14 more columns. They then form and pour Stair 1. They move the TLS up so that it is fully operational. If possible, they move about 30 Dokamatic tables that day.
- Day 3: They strip what they poured the day before, then continue to move tables. They will use a total of 86 tables on the job, and on this day will aim to move 30 to 35. Then they pour eight more columns.
- Day 4: The Harcon crew strips the eight columns they poured the day before and starts filling with plywood between the tables. They complete the A section of the building with guardrails.
- Day 5: They complete the B section of the building with guardrails.
- Day 6: They complete the C section of the building, and the formwork is ready.
- Day 7: The crew tries to take a day off.
- Day 8: They pour again at night, and the entire process begins again the next day.
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With nearly 50 years experience in formwork engineering, Doka serves customers in more than 35 countries and has participated in construction of some of the world’s best known structures, including the world’s tallest skyscraper (Burj Dubai), the Hoover Dam Bypass bridge, and many other projects of all sizes. For more information, please call 877.365.2872 or visit www.dokausa.com.
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