BIG BOOMS, SMALL GROUTERS PUMP FLORIDA COURTHOUSE 2002
When Bobby Powell started Central Florida Concrete Service in 1991, his sole pump was a 1988 Meco P-30 that he transported to jobsites on a 1976 Chevy flatbed trailer. The following year Powell bought a Schwing P-88 small-line pump and gained experience on small jobs, mostly pumping tie beams and filling concrete block for walls on residential and light commercial projects in Gainesville. CFCS has since added six new line pumps and five boom pumps, all Schwing units.
"The boom pumps enabled us to move up to large projects, while we continue to perform our small-project work and expand our territory of operation for all types of jobs," Powell explains. We now can cover all of north-central Florida and much of southern Georgia." Typical of the larger jobs recently taken on by CFCS are a medical center and a new football stadium, both for the University of Florida. His well-balanced fleet of trailer-towed line pumps and truck-mounted boom pumps provides the flexibility to work on jobs of all sizes.
A current project calls for boom pumps on mass footing and deck placements, and small line pumps to fill concrete blocks for interior walls. The highly visible $18.4 million project is for a new courthouse in downtown Gainesville for project owner Alachua County.
Rising on a six-sq-block site that allows for green space and ample parking, the steel-framed structure will have four stories and stand 64 ft high. General contractor PPI Construction Management, Gainesville, started foundation work in January. Working in a 2-foot excavation, CFCS’s 34- and 42-meter pumps boomed mix for a series of 58 individual spread footings, sized at 14x14 ft by 1 _ feet thick. The footers are positioned on an L-shaped building footprint measuring 260x180 feet, and are poured on a compacted granular fill base.
Seven individual mat sections between footers, ranging in thickness from 18 in. to 30 in., were placed to support shear walls. Construction within the foundation also includes the elevator pit that combines poured beams with concrete block. An interior road was graded to the centrally located elevator pit to accommodate CFCS’s Schwing P305 trailer pump and ready-mix trucks, while avoiding lengthy pipeline over the foundation. The pump filled the elevator block with a 3,500-psi pea-rock mix that slumped at 8 inches. The footer, mat and block pours completed the foundation work by mid-April.
"The courthouse site is a large one," says Powell, "but the building itself is close to Main St. and 2nd Ave., so traffic was a concern for the mix trucks. But we were able to position the two boom pumps on the south and west sides of the pour, and complete the foundation without adding line system beyond the booms. The 42-meter Schwing – with its longer reach – made about 75 percent of the pours."
By May 31 the building’s steel framework had advanced sufficiently to allow the first suspended deck pours. Steel erection limited the pace of the pumps on these decks as iron workers felt the pressure of the Schwing 28- and 34-meter boom pumps behind them.
"We’re limited to pumping just two days a week because we’ve been outrunning the steel people," Powell says. "We’re only working four hours a day, and that includes pump setup time in the early morning and clean-up afterwards. We’re putting down 125 to 150 yards on Tuesdays and Thursdays, but we could easily double that if it weren’t for the waiting time."
On non-pouring days at the courthouse Powell moves his pumps to the University of Florida campus and other jobsites in keeping up with a busy pumping schedule. The football stadium and Shands Hospital project at the university’s medical center are among a number of jobs that are keeping his entire fleet busy.
The suspended slab pours at the courthouse are 5 _ inches thick on metal decking, and require 140,000 sq ft total coverage for the four floors. The Schwing boom pumps are positioned similarly to their locations for the foundation pours, but require up to 150 ft of added line system on each pump for the higher deck pours. Each leg of the L-configured deck requires two separate pours of 3,000-psi lightweight mix supplied by Florida Rock Industries. Individual pours range from 100 to 150 yds/day, with about 300 yds necessary to cover 1/3 of a deck, according to Powell. By mid-July over half of the deck concrete was in place as contractors worked for a late August wrap-up.
Work progresses on a series of interior concrete block walls as the upper deck concrete is poured. The labor-intensive work to construct stairwells, elevator shafts and prisoner holding areas requires some 30 masons, plus a small pumping crew to fill the block voids for greater wall strength. Florida Rock is providing the 400 cu yds of grout needed to fill 62,000 blocks, sized at 8 and 12 inches. The combined block and deck work keeps three of Powell’s pumps committed to the job, as upper deck pours are made in the morning twice weekly and block-wall pours are started at 1:30 every working day.
"Ten courses of block are placed to create an 8-ft-high wall before we come through with the pump," Powell explains. " We use either the Schwing P-88 or the P-305, depending on availability. Including pump set-up and clean-up time, we complete about 150 linear feet of wall in a three-hour day. The elevator and stairway block continue on up for all four floors, so our pumping crew and the masonry crews are working from scaffolding and from the completed portions of the upper decks."
Access to the jobsite could hardly be more convenient for both the pumper and the mix supplier. Central Florida Concrete Service, Powell says, has its shop located just two blocks from the courthouse site, while Florida Rock Industries – with five plants located in a 35-mile radius of Gainesville – also has one two blocks from the jobsite.
"We can provide any number of trucks needed for major pours at the courthouse," says Ron Campbell, sales manager for Florida Rock. "We’ve dedicated 12 to 15 mix trucks for this job, and we can load 140 yards an hour if necessary. We designed a 4,000-psi mix for the foundation footings with a No. 67 stone that enabled the pumper to use a smaller, four-inch line – the smallest diameter you can use with a relatively large aggregate."
Bobby Powell’s diversified fleet of big booms and small, mobile line pumps -- working in tandem -- have paced a project that requires mass foundation pours with meticulous block-fill work. The value of fleet diversification lies in his ability to provide the right pump for all job sizes, maintain revenue streams and retain employees by taking on smaller projects when large ones may not be available. From his big 52-meter down to his smallest grout pump, Powell can respond to any concrete placing requirement.
With concrete pours at the courthouse on schedule for a late August completion, general contractor PPI was slated to complete the masonry work with a brick façade. The brick will be grouted over exterior walls of metal studs and gypsum wallboard sheets with ice and water shields. The entire project, says PPI’s Lloyd Kelly, construction manager, has been essentially problem free:
"The only problems came prior to construction," Kelly recalls. "We had to demolish some historical old structures on the site, and this became a political controversy. But the job, itself, has gone smoothly. The concrete pumps have been great. We haven’t had a single breakdown."