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URM Building Retrofit Applications

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Out-of-Plane Wall Bracing

Parapet Bracing

Once the walls have been anchored to the diaphragms, the unbraced length of these brittle walls may cause them to buckle out-of-plane during lateral loading. Where the height-to-thickness ratio of the walls exceeds the limits given in the existing building code or standard, additional bracing should be utilized between diaphragms to increase the out-of-plane strength of the URM wall assembly. This can be done by attaching wood or steel strongbacks to the walls. Another option is to add Fiber Reinforced Polymer (FRP) or Fabric-Reinforced Cementitious Matrix (FRCM) to the walls. The use of FRP and FRCM will also greatly increase the in-plane shear strength without adding significant weight to the building.

View Drawings in Gallery

Simpson Strong-Tie Products for Out-of-Plane Wall Bracing

There are a number of epoxy solutions that may be used to repair structural concrete and masonry that cover a wide range of crack widths and applications.

Structural Epoxy Repair

There are a variety of innovative cold-formed steel solutions available for retrofit project connections, including clips and bridging connectors.

CFS Clips and Bridging Connectors

Composite Strengthening Systems (CSS) provide efficient solutions for the structural reinforcement and retrofit of aging, damaged or overloaded masonry structures.

Composite Strengthening Systems
Joist Hangers

AT-XP® is a fast-cure, all-weather, high-strength anchoring adhesive and may be used to anchor threaded steel rods or deformed steel reinforcing bars in unreinforced masonry.

AT-XP High-Strength Adhesive
ET-HP Epoxy Adhesive

ET-HP® is an epoxy-based system for use as a high-strength, non-shrink anchor-grouting material and may be used to anchor threaded steel rods or deformed steel reinforcing bars in unreinforced masonry.

ET-HP Epoxy Adhesive
Steel Adhesive-Anchoring Screen Tubes

Screen tubes are used in hollow base material applications to contain adhesive around the anchor and prevent it from running into voids.

Steel Adhesive-Anchoring Screen Tubes
Strong-Drive Screws

Angles transfer shear forces for wood to wood framing connections. The A35 with 1/2" long screws might be used to transfer shear forces from 1/2" minimum thickness sheathing to wood framing connections.

Strong-Drive Screws

Hand-drive or collated screws may be used to enhance wood diaphragm strength. Strong-Drive structural wood screws may be used for connector or steel to wood connections.


Holdowns are often used to resist out of plane forces, tying the wall to the roof or floor assembly. The HTT5-3/4 holdown uses a 3/4" diameter anchor bolt, which is typically required when anchoring into URM.