This week’s post was written by Griff Shapack, FRP Design Engineer at Simpson Strong-Tie.
Specifying our Composite Strengthening Systems™ (CSS) is unlike choosing any other product we offer. In light of the unique variables involved with selecting and using fiber-reinforced polymer (FRP) solutions, we encourage you to leverage our expertise to help with your FRP strengthening designs. To get started, we first need to determine whether FRP is right for your project. The fastest way to do that is for you to fill out our Design Questionnaire. Our new Excel-based questionnaire collects your project information and helps you use the existing capacity check to evaluate whether or not FRP is suitable for your project per the requirements of ACI 562-16 Section 5.5.2. After the feasibility study, the questionnaire creates input sheets specifically for your project. Continue Reading
The primary benefit of fiber-reinforced polymer (FRP) systems as compared with traditional retrofit methods is that significant flexural, axial or shear strength gains can be realized using an easy-to-apply composite that does not add significant weight or section to the structure. Many times it is the most economical choice given the reduced preparation and labor costs and may be installed without taking the structure out of service. However, it is important to make sure the composite is properly designed following industry standards in order to ensure that it is the right product for the application.
To provide you with a better understanding of the topic, it’s important to dispel some common myths and misconceptions that you might hear about FRP:
Fiber-reinforced polymer (FRP) composite systems can be used to strengthen walls, slabs and other concrete or masonry members in buildings and other structures. The case studies below show ways in which Composite Strengthening Systems™ (CSS) provide valuable solutions for strengthening buildings and other structures for our customers.
Residential Project in San Francisco
The homeowner for this project wanted to repair some spalling concrete on his concrete piers and also wrap the piers with FRP. We worked with the contractor and homeowner to design a cost-effective solution. This was a successful project for all involved, since the alternative was to jacket the piers with costly and unsightly steel jackets.
School Project in Argentina
The goal of the project was to analyze a standard design of approximately 400 schools in Argentina that were built in the 1980s and to make recommendations to retrofit the structures to meet current seismic code requirements. On analysis, it was found that columns were in need of shear reinforcement for the schools to meet the new seismic requirements.
Hospital Project in Butler, PA
The Engineer of Record on this project wanted to provide continuity across the slab construction joints, something which the existing rebar did not provide. We provided a design of Near-Surface-Mounted (NSM) laminates, which are installed in saw-cut grooves in the top of the concrete slab. This installation allows a flush finished surface, important for allowing the floor finishes to be installed on the slab.
Silo Project in Garden City, IA
The concrete silos on this project had spalling at the top portion, which caused a hazard at this site. After repairing the concrete, we provided a ring of carbon fabric to assist in keeping the top concrete of the silos solid for years to come.
Bridge Project in MN
MNDOT wanted to gain experience working with our CSS products on one of their bridges. We worked with their staff to design several types of strengthening solutions for bridge pier caps and columns. We then provided onsite installation training for the MNDOT maintenance staff to install the FRP products on the bridge.
We recognize that specifying Simpson Strong-Tie® Composite Strengthening Systems™ is unlike choosing any other product we offer. Leverage our expertise to help with your FRP strengthening designs. Our experienced technical representatives and licensed professional engineers provide complimentary design services and support – serving as your partner throughout the entire project cycle. Since no two buildings are alike, each project is optimally designed to the Designer’s individual specifications. Our pledge is to address your specific condition with a complete strengthening plan tailored to your needs, while minimizing downtime or loss of use, at the lowest possible installed cost.
Your Partner During the Project Design Phase
During the Designer’s initial evaluation or preparation of the construction documents, Simpson Strong-Tie can be contacted to help create the most cost-effective customized solution. These plans include detailed design calculations for each strengthening requirement and design drawings with all the necessary details to install the CSS system. Simpson Strong-Tie Engineering Services will work closely with the Design Engineer to provide all the necessary information required to design the system.
Why Use Our Design Services?
Assess feasibility studies to ensure suitable solutions to your application
Receive customized FRP strengthening solutions
Work with our trained contractor partners to provide rough-order-of-magnitude (ROM) budget estimates
Collaborate during the project design phase
Receive a full set of drawings and calculations to add to your submittal
Maintain the flexibility to provide the most cost-effective solution for your project
Gain trusted technical expertise in critical FRP design considerations
In this free webinar we dive into some very important considerations including the latest industry standards, material properties and key governing limits when designing with FRCM.
Continuing education credits will be offered for this webinar. Participants can earn one professional development hour (PDH) or 0.1 continuing education unit (CEU).
For complete information regarding specific products suitable to your unique situation or condition, please visit strongtie.com/css or call your local Simpson Strong-Tie RPS specialist at (800) 999-5099.
This week’s post comes from Brad Erickson, who is the Engineering Manager for the Composite Strengthening Systems™ product line at our home office. Brad is a licensed civil and structural engineer in the State of California and has worked in the engineering field for more than 17 years. After graduating from Cal Poly, San Luis Obispo with a B.S. in Architectural Engineering, he worked for Watry Design, Inc. as an Associate Principal before coming to Simpson Strong-Tie. Brad is the Engineering Manager for Composite Strengthening Systems and his experience includes FRP design, masonry and both post-tensioned and conventional concrete design. While not at work, Brad enjoys spending time carting his three kids around to their competitive soccer games and practices.
Have you ever had a concrete or masonry design project where rebar was left out of a pour? Chances are, the answer is yes. Did you wish you could solve this problem by putting rebar on the outside of that element? That’s exactly what Simpson Strong-Tie Composite Strengthening Systems™ (CSS) can do for you and your project. In effect, composites act like external rebar for your concrete or masonry element. Composites can be used in similar configurations to rebar but are applied on the exterior surface of the element being strengthened.
The initial offering in our CSS line is our fiber-reinforced polymer (FRP) product group. An FRP composite is created by taking carbon or glass fabric and saturating it with a two-part epoxy which, when cured, creates the composite. Together, the weight of the fabric and the number of layers in the composite determine how much strength it will add to your concrete or masonry element.
Another form of FRP composite is a precured carbon laminate. The carbon fibers are saturated in the manufacturing facility and are attached to the structure using CSS-EP epoxy paste and filler, an epoxy with a peanut butter–like consistency. We also carry paste profilers (pictured below) that help contractors apply the proper amount of paste to a piece of precured laminate.
Of course, before any concrete or masonry reinforcement project can succeed, proper surface preparation is of the utmost importance. Without a good bond with the substrate, a composite will not be able to achieve the intended performance. Concrete voids must be repaired, cracks must be injected and sealed, and any deteriorated rebar must be cleaned and coated. Prior to composite placement, the surface of the substrate must be prepared to CSP-3 (concrete surface profile) in accordance with ICRI Guideline No. 310.2. Grinding and blasting are the most common surface-preparation techniques.
The following are just a few applications where composites can be used for concrete and/or masonry retrofits. The orange arrows show the direction of the fibers in the fabric – in other words, the direction in which the composite provides tension reinforcement.
This is a summary of the basics of composites and their installation on strengthening projects. As composites are not yet in the design codes in the United States, the American Concrete Institute has produced 440.2R-08: Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures. This guide has numerous recommendations for using fiber-reinforced polymer systems to strengthen your concrete or masonry construction.
If you would like more information about FRP design, you can learn the best practices for fiber-reinforced polymer (FRP) strengthening design during a recorded webinar offered by Simpson Strong-Tie Professional Engineers. We look at FRP components, applications and installation. We also take you behind the scenes to share the evaluation process informing a flexural beam-strengthening design example and talk about the assistance and support Simpson Strong-Tie Engineering Services offers from initial project assessment to installation.