FRP Witness Panel Preparation and Testing – Lessons Learned and Best Practices

As a Composite Strengthening Systems™ Field Engineer at Simpson Strong-Tie, I’ve supported many composite strengthening projects from design through construction and had hands-on experience troubleshooting issues with FRP witness panels. Through these experiences, I’ve learned a few lessons and developed some best practices worth sharing with anyone in the engineering and construction communities who may encounter similar issues.

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Strategic Alliance with Structural Technologies Brings End-to-End FRP Solutions to Concrete Strengthening and Repair Industry

Simpson Strong-Tie and Structural Technologies formed a strategic alliance for Composite Strengthening Systems (CSS) products in 2021. CSS products include fiber-reinforced polymer (FRP) and fabric-reinforced cementitious matrix (FRCM) strengthening systems. Additionally, where CSS products are not a viable solution, the alliance can also offer recommendations and design for other non-CSS or conventional strengthening solutions. This alliance allows each firm to specialize in their areas of expertise: 

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Project Profile: Reinforcing Concrete Joists to Increase Load Rating

We’re excited to share another fiber-reinforced polymer (FRP) project that required both flexural and shear strengthening (photo below) of reinforced concrete joists to enable the slab floors to carry more live load. The structure is in Southern California, and appears to have been built in the 1950s or 1960s when pan joist construction was common. The EOR for this project, Structural Focus, is an experienced structural engineering firm known for seismic retrofit solutions. The FRP applicator was FD Thomas Structural Specialties, a contractor with decades of FRP installation experience.

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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.

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Reasons to Specify SET-3G Adhesive for Anchorage in Concrete Construction

Weve been receiving a lot of requests lately from engineers wanting to know exactly what the difference is between Simpson Strong-Tie’s relatively new adhesive, SET-3G, and its predecessor, SET-XP®. Both are epoxy-based adhesives used to anchor threaded rods and reinforcing bars in concrete base material for structural applicationsIf you perform a live pull test on a ½“-diameter mild steel rod embedded 4 deep in 3,000 psi uncracked normal-weight concrete, the result will likely be the samein both cases, the steel rod will break in a ductile manner at around 11 kips. You can see this hourglass-shaped steel failure mode happening in Figure 1. (To learn more about anchorage failure modes and ductility, check out this blog). Yet, the SET-3G design values shown in ESR-4057 come out ahead. But why? 

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Case Study: Shoring Up Aging Concrete Grain Silos with Fiber-Reinforced Polymer

The Simpson Strong-Tie® Composite Strengthening Systems™ was used to restore and strengthen 6 distressed cast-in-place concrete grain silos with a combination of carbon and glass FRP, meeting a tight timeline and budget.

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Case Study: Manzanita Hall

Manzanita Hall is one of three remaining buildings on the University of Nevada, Reno, campus that were constructed prior to 1900. Originally named the Girls’ Cottage, Manzanita Hall was built in 1896 and was used to house 97 women in double and single rooms. Architecturally, it a created a Victorian atmosphere and offered a spacious student lounge, complete with a grand piano and a spectacular view of Manzanita Lake.

Several years ago, the hall was deemed seismically inadequate, and the electrical, plumbing and HVAC systems were likewise found to be seriously outdated and insufficient for modern college life. These structural deficiencies necessitated its closure in 2015.

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Case Study: North Yonkers Pump Station

Simpson Strong-Tie precured carbon laminate (FRP) system was used to strengthen unreinforced concrete masonry walls to meet New York City Department of Environmental Protection (NYC DEP) measures to minimize the impact of the next superstorm on critical infrastructure.

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Case Study: The Freeborn County Fair Grandstand

The Freeborn County Fair in Albert Lea, Minnesota, has a rich history going all the way back to 1859, a year after Minnesota became a state. In addition to its longevity as a county fair facility, the Freeborn County Fair is known for its large and spacious grandstand and the many attractions it has hosted since it opened in 1940 — including motorcycle races, stock car races, auto thrill shows, horse races, wrestling events, mule races and tractor pulls.

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