Senior project manager Jerry Stafford faced a forming dilemma. His company, Taylor Ball Construction, got the contract to pour almost 11 1/2 miles (60,000 lineal feet) of riser seating for the new Kansas City International Speedway. The project specifications required that the riser steps not be more than 1/4 inch out of plum nor deviate in straightness more than 1/4 inch in 10 feet, with a maximum of 1/2 inch in 30 feet. Because setting the riser forms fast and accurately was the top priority, Stafford originally intended to use a gang-form system moved into position by crane. But crane access on the job was restricted, and Stafford was aware of a similar project where specification requirements for straightness weren't met because the multiriser gang-form system used had shifted during concrete placement. Deciding instead to use hand-set forms, Stafford was confronted with another problem-how to meet the high production rates required by the project schedule.
Traditionally, hand-set forms for a project of this type would require the use of wood kickers as braces. How-ever, this bracing method was rejected because it would slow down the job and boost labor and material costs. Fortunately, Taylor Ball discovered the solution to the bracing problem at World of Concrete 2000-a reusable metal bracing system called the Adjustable Kicker.
Origins of the "Kicker"
Tim Colatruglio, a third-generation concrete contractor, invented the metal bracing system because he was bothered by the large amount of waste involved with wood forming and bracing for low-wall pours. Bracing lumber had to be discarded after only a couple of uses.
The Adjustable Kicker is lightweight (each brace weighs 16 pounds), folds up for easy storage, and attaches easily to both the form and the base. It can be used on slopes and where there are grade changes, yet adjustment for plum and straightness is easy. Workers use a hand-operated cam lever to tighten the brace after the form is properly positioned.
Contractors save the most money when using the brace for repetitive applications. If the brace is left attached to the form when the form is moved, only the base of the brace needs to be attached at the new location. Crews can attach the base in several ways, depending on forming requirements. They can use metal stakes to attach the brace to the subgrade (stake pockets are built into the brace's base), bolts or masonry nails to secure it to concrete, or screws to attach it to plywood forms.
Recommended uses for the Adjustable Kicker included bridge-deck forming, curbs, grade beams incorporated with floor slabs, grade beams poured over footings, and stadium seating. According to Colatruglio, the brace can be used on walls up to 2 feet tall, and he is currently developing a brace for 3-foot-tall walls. Recommended brace spacing is every 4 feet if the concrete is 12 inches thick, and every 2 feet if the concrete is 2 feet thick.
Saving time and money
Taylor Ball has been using the metal bracing system to place 1,000 to 1,700 lineal feet of riser step every 2 days. Stafford thinks his crew, as it gains more experience, will eventually be able to form and place 2,000 lineal feet per day.
The forms for the riser seating are 24 feet long and 12 inches high. Workers attach the braces permanently to each form every 4 feet. For the first riser step, they secure the base of each brace to the subgrade using metal stakes. For all subsequent pours, they anchor each brace to the concrete from the preceding riser placement by drilling a hole into the concrete and pounding into it a double-headed nail alongside a piece of tie wire.
Cost accounts for the project are favorable to date. "We have saved both money and time by this decision, with labor and material costs for forming on the project running approximately 40% below budget," Stafford reports. Stafford credits the good numbers to the decision to use the metal bracing system, which makes the forming operation very fast. "We have a good crew on the job, which also helps," he adds.
Taylor Ball also builds parking decks, and plans to use the Adjustable Kicker for bracing the perimeter beam forming. "The brace can also be turned so that the long side of the tri-angle is vertical and the short side is facing down, secured to the base," says Stafford.
Below: On subgrade, the brace is
secured and positioned with metal stakes.
Notice that the form is supported over a footing pad.
Right: The bracing system allows
long form lines, such as this one, to be quickly
adjusted for starightness and plumb.
Project: Kansas City International Speedway
General Contractor: Turner Construction Co., Kansas City, Mo.
Concrete contractor: Taylor Ball Construction Co., Kansas City
Brace Manufacturer: Adjustable Kicker Co., Delaware,Ohio.