Located in Pine Bluff, Ark., the paper mill facility for Evergreen Packaging was in need of additional storage space. Upon the removal of their No. 3 paper machine, the large 120-foot by 20-foot space was exactly what they needed, except the space was an open hole on the second floor. The owners decided they wanted this as their storage space but did not know how to fill in this area and make it a structurally sound floor that could carry up to 600 pounds per square foot. 

Structural Preservation Systems (SPS) had worked at the plant several years prior to this project and were selected for this job because of their extensive experience with large structural concrete slabs that span great distances as well as their experience with strengthening structures. Working with a professional engineer from Wisconsin, SPS managed the engineering and design for a new reinforced concrete slab that was supported by the existing building frame. The engineering analysis included existing beams, columns and footings for new loads that would be added. Once the design was complete, SPS had to remove an existing concrete bridge that was in the area as well as a heavily reinforced concrete curb that was 18-inch tall and 24-inch wide. The curb had a tremendous amount of steel in it. Several methods, including chipping hammers, Bobcats and a wall saw, were used initially in an attempt to remove the curb. However, there was so much reinforcement that the crew opted to use a wire saw to remove it.

Upon completion of the bridge demolition and the curb removal, a scaffolding deck was installed that was the length and width of the opening. Since the scaffolding was higher than 4 feet off the ground, 100 percent tie-off was required at all times. The scaffolding deck was used to install the engineered formwork that supported the concrete during placement. Temporary shoring was installed to support the forms and a special engineered deck was fit into place. After the deck was complete, two rebar mats were installed and a series of dowels were used to tie this new concrete slab into the main structural beams.

Because this project was completed while the mill was in operation, the crews had to work next to the No. 2 paper machine while it was still in operation creating a hot and noisy work environment. 

The 100 cubic yards of concrete needed to be placed in one pour, which was a challenge for the second floor location inside the building. A boom truck was used that could pump concrete through a window on the second floor into the formwork. An overhead Gantry crane was used to facilitate moving the large concrete hose, much safer than having employees move the heavy hose. To minimize shrinkage cracking at the site, SPS allowed the concrete to wet cure for seven days utilizing water sprinklers and burlap.   

The owner was extremely pleased with the result of the project. They now have the storage space they desire and the confidence that the structure can handle the tremendous loads.