Case Study: Gruening Middle School’s Seismic Damage Repair Solution

It can be a challenge to repair an earthquake-damaged structure.

During the 7.1-magnitude 2018 Anchorage earthquake, Gruening Middle School in Eagle River sustained more damage than any other school in the Anchorage School District. Review of the school showed the existing masonry walls suffered damage and separation from the roof. During the retrofit design, the Reid Middleton structural engineering team (Anchorage) determined the masonry walls weren’t adequately reinforced to meet current code requirements. They were seeking an easy-to-install strengthening solution that wouldn’t add significant weight to the building.

The Simpson Strong-Tie team visited the site during the design phase. We suggested using fabric-reinforced cementitious matrix (FRCM, ICC ESR-3506) for strengthening existing masonry walls. FRCM combines a high-performance sprayable mortar with a carbon-fiber grid to create a thin structural layer that won’t add significant weight or volume to the existing structure. In addition, FRCM is easy to install over fluted masonry walls.

Our team worked with Reid Middleton’s Ellen Hamel and David Stierwalt specifying FRCM to strengthen 36,000 square feet of walls. Our team also trained Generation Plastering, based in Pasco, Washington, to install the FRCM system. Kudos to their team for an excellent first few days of FRCM installation. Cornerstone General Contractors is the GC on the project. We especially want to thank the school district for being open-minded about using FRCM.

Simpson Strong-Tie Team: Alex Daddow, CSS Field Engineer; Eric Olsen, CSS Specialist; Aniket Borwankar, Development Manager.

Feel free to contact our team with questions or for assistance with your project.

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Author: Simpson Strong-Tie

For more than 50 years, Simpson Strong-Tie has focused on creating structural products that help people build safer and stronger homes and buildings. Considered a leader in structural systems research, testing and innovation, Simpson Strong-Tie is one of the largest suppliers of structural building products in the world. The company is committed to helping customers succeed by providing exceptional products, full-service engineering and field support, product testing and training. Simpson Strong-Tie works closely with industry professionals to provide code-listed, field-tested products, and value-engineered solutions. Its product lines include Structural Connectors, Fasteners, Wood and Steel Strong-Wall® prefabricated shearwalls, Anchor Tiedown Systems for multi-story buildings, Quik Drive® auto-feed screw driving systems, and Anchor Systems for concrete and masonry. Simpson Strong-Tie products are known for their consistent quality and availability as well as for helping structures resist high winds, hurricanes and seismic forces. Simpson Strong-Tie has a national sales force and field engineers that are available to assist with specification and jobsite issues. Products are distributed nationally through an extensive network of distributors and dealers.