Carbon Fiber Structural Repair Exterior Block Wall

Problem

This concrete masonry building had experienced cracking damage at the corners and around window and door openings. The building was occupied by several different businesses, including a Montessori School, infant daycare, and retail storage area.

Y2 Consultants of Jackson Wyoming conducted an assessment including an infrared scan of the building that revealed construction deficiencies. The structural assessment of the building noted that the cracks were due to differential loading and insufficient horizontal rebar at the corners to tie the perpendicular walls together.

The differential loading and insufficient rebar had stressed the CMU to crack in these loca-tions. In order to allow safe occupancy of the building, it was determined that a retrofit of the deficient areas was necessary. Repairs would need to be coordinated with the businesses using the building, without a lot of disruption.

Solution

A Carbon fiber retrofit repair process to strengthen the walls at the cracked corner areas was determined to be a viable solution. CST’s carbon fiber repair system is comprised of high strength carbon reinforced fabric strips, applied over a clean and prepped surface, and adhered using a high strength epoxy. CST crews first prepped the surface using surface grinders to remove existing paint and get the surface profile required. A boom lift was used to help the crew safely reach areas above the awning. CST power washed the exterior of the building where the carbon fiber reinforcement would be applied. Moisture tests of the block surface were taken to ensure project specifications were met for the surface conditions necessary to achieve maximum adhesion properties of the material. Once dry, primer, then a tack coat, and then saturated carbon fiber was applied to the wall followed by a final grey UV exposure rated coating to protect the material.

Result

CST crews successfully reinforced deficient and cracked areas of this concrete block building in a matter of days.
The carbon fiber retrofit allowed the owners to keep business running and provide additional support to extend the useful life of the building for many more years. Carbon Fiber repair options such as the method used on this concrete masonry building strengthen existing structures, and provide a higher safety factor.

For many older structures, where reinforcement may not have been included during construction, carbon fiber retrofit helps to stabilize and reinforce areas of concern, bringing older buildings up to current code regulations and extending their useful service life.

CHALLENGES

• Perform the repair without disrupting tenants of this commercial building.
• Prepping the surface to meet specification for maximum adhesion of the car-bon fiber material.
• Accessing areas above the awning of this structure to prep surface and install carbon fiber material.

BENEFITS

• In situ, non-disruptive repair.
• Increased safety factor through strengthening of existing structural deficiencies.
• Meeting current code regulations, allowing older buildings to continue to be used.