Project-Removing 1.2 million lbs. of concrete from operating hospital without disturbing normal hospital activities.

The University of Michigan Health Center is a extraordinarily busy place. The complex consists of nearly five million square feet of buildings. The complex includes three separate hospitals (C.S. Mott Children's Hospital, University Hospital and Women's Hospital). Over 17,800 people are employed by the University of Michigan Health
System. Typical activity over the course of a year includes:

While Rockey Bennett from Construction Services wanted the 1.2 million lbs. of concrete removed, it was made clear to Ohio Concrete personnel that ongoing hospital activity took priority over the demolition work. To minimize the impact on hospital activity, Ohio Concrete made a decision to use electric concrete saws, fork trucks and an excavator. The use of electric equipment eliminated any fumes normally associated with gasoline or diesel powered concrete saws. All construction activity had to occur between 7:30 a.m. and 5:00 p.m. Sawing activity was restricted to six hours a day between the hours of 9:00 a.m. and 3:00 p.m. Crews had to cooperate with hospital personnel when using a freight elevator when transporting the concrete to the closest loading dock. It quickly became apparent it was not practical to try to use the elevator between the hours of 11:00 a.m. and 1:00 p.m.

Over the past few years Ohio Concrete Sawing and Drilling has purchased several electric powered fork trucks and excavators in an effort to remove concrete from the inside of buildings in the safest and most efficient manner. When Ohio Concrete's operators removed a concrete ceiling at the University of Michigan, they used a small electric fork truck to support the ceiling while sawing and cutting into 3 x 7-foot pieces of ceiling weighing about 1,000 lbs.

Ohio Concrete attached a wall saw to scaffolding allowing their operators to cut the ceiling upside down from below. The scaffold was locked into place using jack screws to insure the wall saw was secure during the sawing operation. Attaching the wall saw to the scaffold allowed the operators to saw the 4,500 square feet of ceiling from below without exhausting their operators. Sawing the ceiling while it was supported in this manner was the fastest and safest way of removing the ceiling. The hydraulic wall saw was powered by a 40HP electric hydraulic power source. It would have been impossible to do any of the work from above the ceiling because of the congestion. The area was very congested with steam lines, water and sewer lines, electric conduit and piping for oxygen. Attempting
to break the concrete from below would have been very dangerous to the construction personnel and surely would have damaged some of the utilities resting on the concrete being removed. Also, breaking the concrete would have created far more noise and dust than the sawing did.

After the concrete ceiling was cut and lowered to the floor, the pieces were then moved to the elevator and taken to the dumpsters for disposal. The University of Michigan takes the concrete to a crushing facility and always makes an effort to recycle their building materials.

Prior to removing any of the floor, Ohio Concrete personnel finished the sawing and removal of the ceiling. This gave them a solid surface for operators to operate the fork trucks and walk ons. The floor was cut using a 40HP electric concrete saw. The entire area was cut into 4 x 4-foot squares. Removal of the floor was done using electric fork trucks and a mini electric excavator. Normally crews would have used their fork trucks to remove this concrete, but discovered the mini excavator was faster. The excavator was faster because it did not require the use of any anchors normally used when removing concrete with a fork truck. The excavator also had more leverage when lifting pieces that contained abandoned plumbing lines, electrical conduit and reinforcing at the bottom of the floor slab.

This job was very successful not only because it was completed on time, it was also done with minimal disruption to hospital activities. The tools used created no fumes, no vibration and very little noise. Employees working one floor away were unaware that crews were removing over one million lbs. of concrete from the floor below.

Ohio Concrete has been in business for 25-years. Skip Aston, who started the company in 1981, is chairman of the safety committee for CSDA. During the busy season Ohio Concrete completes approximately 2,000 jobs a month in Ohio and surrounding states. Ohio Concrete focuses their efforts on service work. Many of their trucks are equipped with generators powered through a PTO. These generators allow them to use 40HP electric saws very easily without having to connect to 480-Volt power in the building where they are working.