Expectations for Tilt-Up Construction
By: Liz Toohey, CVC Construction Corp.
Building challenges arise on any project. Building a three-story Class A Tilt-Up adds to the challenges in many ways. For CVC Construction of Northern California, the challenges on its recent project in Folsom, California, were reduced by strategic thinking and planning.
Curtis Weathersbee, Project Manager for CVC Construction, explains it this way: “We really encountered some design challenges on the project. The building foot print was roughly 34,000 square feet, allowing only one-third of the Tilt-Up panels to be cast on the building slab itself.”
A LITTLE PLANNING GOES A LONG WAY
CVC is strategic in its planning and execution of Tilt-Up projects. With an average daily crew of 13 workers (including the site superintendent), CVC began its 8 week contracted schedule. Because of the short schedule, all of the panels had to be erected at one time. The thin-set casting slabs had to be placed around the project in specific locations so that the crew could efficiently lift the panels and place them in one lift with a crawler crane.
The tallest panel on the job was 53 feet high, weighed 124,000 pounds, and was three stories tall. CVC constructed panels with an 8-inch structural thickness that required the use of strongbacks on the panels. Strongbacks are a structural steel method used to reinforce critical areas of Tilt-Up panels during erection. Panels with narrow concrete legs may require strongbacks for added strength during erection. As a guideline, when any leg is less than 2 feet wide or any panel thickness is more than 7 inches, it is recommended that one or several strongbacks be used.
Assembled strongbacks have an open slot over the entire length to accommodate most bolt patterns. Some strongbacks include a fastener system for temporarily securing a reinforcing beam or the like to the poured concrete panels. They also include an anchor to be set in poured concrete with an exposed handle portion free of the concrete, and a shaft with a slotted end for receiving the handle portion. A spring-loaded pin in the slot retains the handle portion in interlocking engagement with the shaft. An opposite end of the shaft secures a strongback beam to the concrete structure.
The strongbacks allowed the CVC crew to lift the panels without them breaking, which would have happened using a more traditional lifting method. The strongbacks then had to be removed from the panels before they were placed in their final location.
“Not only were we lifting these panels in a tight area, but we also had to have a second crane there, removing these strongbacks as we lifted up the concrete wall,” says Weathersbee.
To accomplish this, CVC used two cranes on the site: a Manitowoc M250 Series 2 crane and a 70-ton hydraulic crane. As they lifted the Tilt-Up wall into place, workers unbolted the strongbacks, and hooked it to the other crane. They then swung the strongbacks out of the way and placed the panel in its final location.
CVC stuck to its project schedule, working well with the general contractor, Brown Construction of West Sacramento, California, and the subcontractors, including Maxim Crane Service and ready-mix supplier Central Concrete Supply Co., Inc.
Another subcontractor that did an excellent job was West Coast Sacking, Inc., which was responsible for patching all of the concrete panels. “They’ve done an outstanding job,” notes Weathersbee. “The overall quality on the finish of the exterior panels was excellent. They paid really close attention to detail, and they did it in short order. Within the scheduling time constraints, they were very responsive to the project’s requirements.”
TILT-UP ON THE RISE
According to www.tilt-up.org, Tilt-Up construction is one of the fastest growing industries in the United States. At least 10,000 buildings enclosing more than 650 million square feet are constructed using Tilt-Up panels annually. These buildings are growing in popularity because they are cost-effective and quick to build, and they are durable and easy to maintain.
CVC Construction managed to set up the foundation, set the slab, form the Tilt-Up panels, and place the panels for the Folsom project, all within a quick 8-week schedule and with design challenges making it less than a perfect jobsite. With its fast-track delivery and high quality of work, CVC has made a name for itself as a trustworthy and reliable company that gets the job done no matter what the conditions.
“CVC Construction takes pride in working under tight time constraints, and that had a lot to do with us being awarded the job,” says Weathersbee. “We knew upfront that there was only an 8-week build schedule to have the walls in place, and we knew we could do that. We take pride in meeting and beating schedules.” The three-story building has a total of 102,000 square feet.
CVC Construction has earned the reputation as an industry leader for providing exceptional quality, dependability, and on-schedule, on- budget delivery with a strong emphasis on safety. For more information, please call 916.859.3159, e-mail liz. toohey@cvcconstruction.com, or visit www.cvcconstruction.com.
