Below Grade Gymnasium Wall Stabilization
Epp Concrete Construction reached out to Rhino Carbon Fiber for assistance in coming up with a solution to reinforce a bowing gymnasium wall on a project that they were working on. Typically, bowed wall repairs are installed on walls from crawl space height to anywhere from 7′ to 10′ in height. In this case, the wall was 18′ tall. To complicate matters more, there were four large windows on the wall.
Prior to addressing the bowing wall, drainage issues on the exterior of the building had to be addressed. Often times, saturated soils are the major contributing factor that causes walls to bow. In this case, there was a parking lot adjacent to the below-grade gymnasium and the lot was sloped such that the runoff ended up running right down the back of this wall. The issues were remedied by removing a portion of the parking lot and installing a paved gutter.
Once the water issue was addressed, it was time to strengthen the wall to prevent any further movement. Due to the wall height, Rhino’s 24″ wide 400 gsm unidirectional carbon fiber had to be used. This is the same material as the standard 6″ wide bowed wall strap but additional material was required due to the pressures on the wall. Horizontal straps were also used under the windows to anchor the straps under the windows.
After coming up with the plan to reinforce this wall, Rhino created a drawing for Epp to work off of. Due to the size of the wall and the amount of surface preparation work required for the carbon fiber installation, Epp elected to bring in a subcontractor and abrasive blast the entire wall prior to installing the CFRP, Per ICRI 310-2R, the surface profile of the concrete prior to for CFRP installation should be a CSP4. Once this work was completed, the crew was able to proceed with the carbon fiber installation.
By utilizing CFRP, Epp was able to permanently stabilize the wall without adding any obstructive bracing material to the interior.