| Concrete Cutting & Breaking | Case Study: Wall Sawing

Ohio State University Stadium

Ohio State University Stadium:
Old Shoe Gets New Soul

Venerable Ohio Stadium in Columbus, Ohio has been the home of the Ohio State University Buckeyes for over 75 years. "The Horseshoe", as it is fondly known, has been the scene of many a collegiate battles over the years. Woody Hayes led many Buckeye teams to victory and national football championships.

This is the first major renovation ever done on Ohio Stadium. When completed, The Horseshoe will be the premier stadium in college football with a seating capacity of 98,000. The renovation features: increased seating, widened concourses and aisles, additional restrooms on all levels, expanded concession areas, increased disability seating, elevators and escalators to the upper levels and fewer visual obstructions.

While the benefits to the stadium will be many, one of the main goals was to preserve the look of The Horseshoe. The stadium will be surrounded with an external shell but the rotunda and towers at the north, southeast and southwest sides will all be retained. And the south end will remain open to preserve the original design configuration.

O'Rourke Wrecking Company of Cincinnati, Ohio was awarded the $4 million demolition contract at Ohio Stadium. O'Rourke is a national demolition firm and often works with concrete cutting companies to facilitate their projects.

O'Rouke selected Concrete Cutting & Breaking, Inc. - Columbus, Ohio - because of their reputation and past work experience. In addition, the scope of the concrete cutting for this job required the mobilization of a significant amount of equipment and personnel and CCB could satisfy those requirements with its Ohio branch locations. "We were able to pool resources from the Concrete Cutting & Breaking offices in Columbus, Cleveland and Pittsburgh to meet the demands of this job" said CCB.

The original contract called for Concrete Cutting & Breaking to cut 92 sections of A-Deck seats free. The old A-Deck seats accounted for nearly 40% of the total stadium seating. Each section of seats consisted of 8 rows of seats, measuring 22' by 18' of 15" thick concrete. The seat sections weighed 27,000 pounds and were situated between the 108 rakers. It was decided that four, 2-man crews working 10-hour shifts for five days per week could complete this project.

CCB operators first cut the top section free utilizing push saws with 16" diamond saw blades to cut to a depth of 5.5". CCB also utilized hydraulic handsaws manufactured in their own fab shop in Michigan. After the bottom cut was made, operators used hydraulic wall saws to cut the sides of the seat sections. Blades with diameters up to 54 inches were used for this phase of the project. Once the seat section was cut free, O'Rourke initially lifted out the seat section with a crane. According to O'Rourke's Project Manager, "The fragile nature of the 78-year old concrete necessitated a revised procedure and the sections were instead lowered to the ground, broken and safely remove."

CCB was employed by O'Rourke to cut 480' of 3 1/2" - 4" deep cuts on the B-Deck perimeter. The B-Deck seats were removed on this west side of the stadium to make room for luxury suites to be installed at a later date. CCB used a gas powered handsaw with a 16" diameter diamond blade to make this relatively easy cut. O'Rourke then used remote breakers to demolish the B-Deck seating. The cutting on this phase of the project began on November 15, 1999 and, thanks to the superb team of operators, finished 2 days ahead of schedule, on December 6, 1999.

Once the seat sections were removed, O'Rourke planned to remove the cold joint treads and risers on the top of the rakers with 30 pound chipping hammers. "We quickly discovered that the treads and risers were part of a monolithic pour and could not be removed so easily." In addition, the breakers could have easily damaged the structural integrity of the rakers and this was not acceptable in this renovation project. It also presented a major problem as the replacement precast seat sections were already being fabricated for installation.

The removal of the treads and risers was scheduled to be completed by January 15, 2000. O'Rourke called upon CCB to come to the rescue at The Horseshoe. CCB is often asked to accept such on-site job challenges. CCB is extremely innovative and goal oriented in finding solutions to difficult problems encountered on construction projects. Many of the CCB operators have graduated from Concrete Sawing and Drilling Association training programs including Operator Certification, the highest level of training in the industry.

CCB was able to mobilize 12 operators to make 17 cuts on each of the 108 rakers, to remove the treads and risers on the rakers. The weather and operating conditions proved to be as much a challenge as the job itself. Saw operators had to mount the wall saw track and conduct the sawing operations working from lifts. Each raker required 8 vertical cuts and 9 horizontal cuts; the mounting of wall saw track for such a small cut distance was difficult, especially when working from a lift platform.

Once the track was in place, the operators first used 24" diameter by 1/4" wide saw blades to make the initial cut. Then a 42" diameter wall saw blade was used to make the final cut to full depth. Diamond Products wall saw blades were the mainstays for this project. Because there were to be no overcuts on the rakers, the cut sections had to be knocked out evenly though they were not fully cut.

The weather made sawing even more challenging with subzero temperatures and daily snowfall during this 30-day. In fact, CCB operators operated in subzero temperatures on seven of those days and had eight days lost entirely due to the frigid weather.

The biggest cold weather safety issues of concern to CCB were cold hands and faces from the extreme cold weather. Operators were provided with an ample supply of neoprene gloves and facemasks to minimize cold weather exposure. To keep the water used to cool the saw blades from freezing, CCB operators had to maintain a continuous flow of water, as any type of antifreeze was not accepted on the construction site. This was even more of a challenge because there was no source of water on the job site; water was supplied daily from water tanks on each work truck.

Equipment breakdown also had to be addressed in this weather. A supply of equipment was maintained in reserve to allow continuous cutting operations. Even the lifts were a challenge to keep operating in the subzero weather. CCB also brought in backup equipment from their office in Buffalo, New York.

In spite of these challenges the CCB operators were able to finish the second phase of this $183,000 contract by the February 15, 2000 completion date. "When we talked to O'Rourke about doing the Ohio Stadium job, I felt that we were the best company with the resources and personnel to effectively complete this job on time" said CCB. "The saw operators put in 125% on this job and the wealth of experience from our Cleveland office really helped make a difference on the Ohio Stadium project."