In Weston, Fla., a new five-story office building recently benefited from the speed of tilt-up construction. The building is a project of BHA/Geopack of Miami. Florida Tilt, Inc., is the tilt-up contractor on this project, and the panels are being erected by Sunshine Specialties, based in Orlando, Fla.

The tilt-up wall method can be a quick and cost-efficient way of building — and one key to a successful tilt-up project is having the right crane and an operator who is knowledgeable about the procedure. Sunshine Specialties used a 250-ton capacity Link-Belt LS-278H to set these panels, which in some cases weigh in the neighborhood of 200,000 pounds each and were 80 feet tall.

"These are some of the heaviest and tallest building panels ever erected in the Southeastern United States," notes Ralph Coleman, vice president of operations of Sunshine Specialties.

"But it's not enough just to have the capacity to lift the panels," adds Coleman, who also operated the Link-Belt crane on the project. "Once the panel is raised to a vertical position from its horizontal casting bed I must gently turn the crane and walk it 30 to 50 feet to the building foundation with the 100-ton load suspended from the crane's 160-foot boom."

Sunshine Specialties owns six Link-Belt cranes.

"It seems that each one has a greater lifting capacity or reach than the previous Link-Belt that we purchased," notes Trentis Durden, one of the founders and president of Sunshine Specialties, Inc. He launched Sunshine Specialties, Inc. in 1976 with partner and vice president Raymond Browder.

The first stage of tilt-up concrete construction, notes Ray Cartaya, co-owner of tilt-up contractor Florida Tilt, Inc., consisted of building a slab on which to form, pour and cure the walls in a horizontal position. This casting bed was laid out in relation to where the panels would be erected. To construct it, the ground was leveled with a grader equipped with a Spectra Physics laser, Cartaya notes.

"We have our own laser screed to assure absolute levelness," he says.

A 2- to 3-inch thick unreinforced layer of 3,000-psi base concrete was then poured to serve as the casting bed.

After the casting bed was prepared, each tilt-up segment was then formed to its precise thickness, with inserts to create door, wall and window openings. Steel reinforcement was added as called for in the engineering drawings. Lifting inserts were also installed.

On this project, the 4,000-psi wall concrete was supplied by Florida Concrete Unlimited. Pumps placed the concrete in the forms, and Cartaya notes that about four days were allowed for the concrete to reach the desired strength. Upwards of ten panels were formed and poured at a time. That's about 10,000 square feet of panels that required about 400 cubic yards of concrete.

Once the panels were cured and stripped of their forms, it was all up to Sunshine's Ralph Coleman and the Link-Belt LS-278. During panel erection, Coleman had to exert a line pull force of up to 25 percent over the weight of the panel to gently break the heavy panel free of the suction holding it fast to the casting bed and then smoothly raise the panel for transport. Coleman then slowly walked the giant 401,560-pound machine and its 100-ton load into position, booming up and cabling down to bring the panel fully upright for final placement.

It was a high-precision operation.

"When the tilt wall team leader asks for a sixteenth to an eighth of an inch lift to add or remove a shim, I must have the ability to give it to him," Coleman says.

One interesting aspect of this five-story office building lies in the panel bracing. Prior to having five-story tilt-up panels, all bracing was installed on the interior. But with the steel floor erector needing to work close behind the panel erection process, it was necessary to design and fabricate exterior bracing. This required more time for the bracing crew to complete its work but allowed interior steel erection to continue unhindered.

This project involved casting and placement of a total of 65 concrete panels including the large interior elevator and stairwell units. The largest panel lift was 197,000 pounds at an 80 degree angle and 30-foot radius. The panel was 80 feet 6 inches tall, 17 feet wide and 14 inches thick.

According to Florida Tilt's Cartaya, this job "really was a team effort."

"We are the contractors hired to form, fabricate and pour the tilt-up concrete walls on this five-story office building," Cartaya says. "Normally we do all our own erection with a rented crane. In fact, the first four-story tilt wall building that we erected seven years ago, we did with a rented 150-ton Link-Belt machine. But because the concrete tilt-up slabs are so large and weigh so much on this job, we hired Sunshine to do the final erection."

Once each panel was properly placed and braced, the lifting rig was released — and Ralph Coleman walked the Link-Belt LS-278H II back to the next casting bed to pick up yet another tilt up panel.

"Tilt wall erection has to be done right the first time," Coleman adds, "because there is no second chance."