URM Building Retrofit Resources

Resources for the Retrofit, Repair, Addition and Change of Occupancy of Existing URM Buildings

The following products, resources, and references offer potential solutions for a successful URM building retrofit or repair. A URM building retrofit or repair can reduce the damage experienced from a seismic or wind event and can go a long way to increase the building’s performance, leading to reduced risk to life, repair or replacement costs and down time for these often historic structures.

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.

SET-XP® is a high-strength anchoring adhesive and may be used to anchor threaded steel rods or deformed steel reinforcing bars in unreinforced masonry.

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.

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

There are a variety of mechanical anchor solutions that may be used in cracked and uncracked concrete, as well as uncracked masonry to resist seismic or wind forces or help create gravity resisting connections.

The Heli-Tie helical wall tie is a stainless-steel tie used to anchor building façades to structural members or to stabilize brick walls. The Heli-Tie helical stitching tie provides a unique solution to the preservation and repair of damaged brick and masonry structures.

FX-263 Rapid-Hardening Vertical/Overhead Repair Mortar is a cementitious, single-component, fiber-reinforced, polymer-modified, silica fume-enhanced, structural repair mortar with integral corrosion inhibitor designed for vertical and overhead applications.

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.

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

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.

In retrofit applications, joist hangers might be used to support added blocking or might be installed horizontally to help resist out of plane anchorage forces in addition to their typical download and uplift load applications.

Retrofit and bearing plates are often used in out of plane wall to roof or wall to floor anchorage conditions and utilize a larger bearing surface on the side of an unreinforced masonry wall.

Straps may be used to resist out of plane wall to roof or wall to floor anchorage forces or drag forces when installed on the top or bottom of roof or floor framing. One out of plane force-resisting solution uses the MSTD Marriage Strap, an overlapping in-line splice between an HTT tension tie and a CMSTC16 coiled strap.

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.

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.

The Yield-Link® special moment frame connection provide optimal moment transfer solutions for both new and retrofit projects. Our Yield-Link structural fuse technology ensures the resilience of the frame during seismic events.

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

Hand-Drive or collated nails may be used to enhance wood diaphragm shear strength or for wood to wood or steel to wood connections.

The referenced literature provides information on potential URM building retrofit and repair conditions and solutions, including case studies.

Simpson’s software, literature library, and web app tools are a great resource for registered design professionals designing retrofits.

Federal, State and City Ordinances or Guidance

Unreinforced Masonry Buildings and Earthquakes (FEMA P-774)

California Seismic Ordinances

Utah Guide for Seismic Improvement

Seattle URM Buildings

Portland URM Building Information

Key URM Seismic Retrofit Resources

International Existing Building Code

Seismic Evaluation and Retrofit of Existing Buildings (ASCE 41)

Techniques for the Seismic Rehabilitation of Existing Buildings (FEMA 547)

Example Application Guide for ASCE/SEI 41-13 Seismic Evaluation and Retrofit of Existing Buildings (FEMA P-2006)

Recorded Webinars

Strong Retrofit: Unreinforced Masonry Building Retrofit Using Adhesive Anchorage, Shotcrete and Helical Ties

Strong Retrofit: Unreinforced Masonry Building Retrofit Using Connectors, Fasteners and Strong Frame Moment Frames