What Are FRP Composites? Polymer Resin Matrix Reinforcing Fiber (Glass, Carbon, Kevlar, etc.) Interphase Coupling Agent
Advantages of Carbon Fiber <ul><li>High Strength (400 KSI Tensile) </li></ul><ul><li>Low Weight (less than 0.5 pounds per sq. ft.) </li></ul><ul><li>Corrosion Resistance (pH 2 – pH 13) </li></ul><ul><li>Thermal Compatibility </li></ul><ul><li>Excellent Fatigue Behavior </li></ul><ul><li>Non-conductive (glass), Conductive (carbon) </li></ul><ul><li>Speed of Construction </li></ul><ul><li>Low Cost </li></ul>
Engineering Support <ul><li>Full range of support </li></ul><ul><li>Software assistance </li></ul><ul><li>Full engineering capabilities including stamp </li></ul><ul><li>Minor support and design assistance </li></ul>
Examples of Applications <ul><li>PCCP hoop strengthening </li></ul><ul><li>Missing/under designed reinforcement </li></ul><ul><li>Seismic strengthening </li></ul><ul><li>Cutting or drilling of structural members </li></ul><ul><li>Low cylinder breaks </li></ul><ul><li>Adding capacity </li></ul><ul><li>Underground/Sewer/Water Infrastructure </li></ul><ul><li>Fatigued Members </li></ul><ul><li>Corrosion Mitigation </li></ul><ul><li>Steel Pipe Repair & Strengthening </li></ul>
Cholla Power Plant Situation: The 66" circ line had experienced enough wire breaks that a possible rupture was a major concern. The original repair was only 40-60 linear feet depending on the condition of the pipe. We needed to be able to restore the pressure bearing capacity of the circ line, the overburden was only 8’. Challenges: Time restraint was a major factor, this job there was only a small window of time to do the entire job. The prep work for the job was limited to only within 2 weeks. To remove and replace the line would have involved too much time and disruption of the existing above ground infrastructure. Likewise external tensioning would have taken too long with too much disruption.
Solution: We went ahead and came up with a comparable solution that would not affect any of the above ground infrastructure and still provide the needed support. Carbon fiber was installed in two layers of 20 oz unidirectional in a hoop direction. Conclusion: The original 40 linear feet was done in 2 days. After the completion of the work, APS requested us to complete an additional 120 lf. We mobilized within 72 working hours and completed the additional 120 lf within 5 days.
<ul><li>San Juan Power Plant </li></ul>Situation: Wire breaks in the 10' diameter pipes severely limited the capacity of the pipe to with stand internal pressure. The goal was to restore the capacity of the pipeline. Challenges: All work needed to be done within the time frame of the shut down of 3 weeks for the # 3 circ line and 3 days for the #4 circ line. Replacement was far too costly and too much down time. Steel lining would reduce the flow, cause future corrosion, and would have high mobilization costs.
Solution: It was decided to install 20 oz of unidirectional carbon fiber in hoop direction, because this solution can be done quickly and with little invasiveness. Another supporting reason was because the risk of corrosion would be nonexistent. Conclusion: Before installation took place it was discovered that there were severe cracks where the carbon fiber was to be installed in the hoop direction. 20 oz of carbon fiber was installed perpendicular to the cracks before installing in the hoop direction to help maintain the integrity of the pipe. The job was completed in the time required and is still functioning today.
Missing/Under designed reinforcing <ul><li>Downtown Lofts </li></ul><ul><li>Missing rebar in High Rise </li></ul><ul><li>Column cage missing </li></ul><ul><li>Scottsdale office building floor strengthening </li></ul>
AmeriSchools Academy <ul><li>The City of Yuma dictated that AmeriSchools Academy, built of CMU masonry, be reinforced to protect the students, teachers and workers in case of an earthquake. </li></ul>
The Solution After several solutions were investigated, it was determined that seismic reinforcement could best be achieved with carbon-fiber composites applied to the exterior and interior wall surfaces. North side of building after sandblasting to remove paint in areas where carbon-fiber is to be installed. Front entrance is shown with windows removed and surface sandblasted, now ready for 2 layers of fabric to be installed
The Results The application of carbon-fiber fabrics and laminates proved to be the least expensive and most effective way to provide seismic reinforcement. The client was very satisfied with the product and job coordination. Realizing the challenges the crew faced doing this in the summer when the temperature was between 110 and 120 degrees. The job was completed in time for the school to reopen for classes the end of July. Shown below the crew is installing carbon-fiber laminates on the interior walls and openings. This shows the front entry after the application of bi-directional fabrics. Stucco was later added then painted.
Cutting or Drilling Structural Members <ul><li>DEMA </li></ul><ul><li>Summit at Copper Square </li></ul>
DEMA Renovation <ul><li>On this renovation project (10) 6” pre-cast hollow-core floor planks had numerous penetrations through them for utilities. Many of them were old existing and several new penetrations were created for new plumbing. In many cases these penetrations had severed the post tension cables. </li></ul>
The Solution Fill the old penetrations that were not to be reused. Install 4” wide carbon fiber laminate strips to the underside of the planks in the areas where the penetrations had been filled. At the areas where the new plumbing was protruding we overlaid 12” wide carbon fiber fabric strips in a cross hash pattern over the laminate going 24” past the plumbing on all sides.
The Results The strength lost because of the penetrations and the post tension cables being cut was restored. This allowed the restoration to continue at a great cost saving over replacing the floor planks. Which would have been an enormous construction issue at best.
The Summit at Copper Square <ul><li>This 23 story concrete shear wall residential building had 35 spandrel beams that were cored for pipe sleeves below the approved zone per criteria given by the engineer of record. This caused a lost of capacity of 35 kips in downward shear. </li></ul>
The Solution Install one layer of uni-directional carbon fiber fabric the full width of the beams and wrapping the complete beam. It was determined that any beam with a core 8 ½” or less from the bottom of the beam need carbon fiber support. This replaced the 35 kips structural strength lost by the cores while maintaining the ceiling height in the hallways.
The Results Because some of the plumbing had already been installed the fabric had to be cut to allow the installers to wrap the fabric around the pipes. A second layer of fabric was installed over the cuts in a horizontal direction to prevent lose of strength from the cuts. The job was completed in 2 weeks and the contractor was able to get back on schedule with construction.
Roger Road Treatment Plant Situation: The digestive gasses eroded the existing concrete columns and deteriorated the existing reinforcement. Challenges: The sludge digester needed to be kept free of rocks and pebbles. The floor of the digester was slanted making scaffolding a challenge and more difficult to keep debris out.
Solution: Installers from the Arizona Repair Masons' Specialty Crew reinforced deteriorated columns with carbon fiber composites inside the drained digester tank of the sewage treatment plant. Damaged rebar was augmented with fiberglass rebar. Conclusion: Company was happy with the end results of restoration to the columns. Columns being wrapped with Carbon fiber laminates in order to reinforce the eroded areas.
Added Touch Warehouse Badly spalled and deteriorated columns due to years of water coming from the scuppers with no down spouts.
Added Touch Warehouse <ul><li>After the concrete repairs were made carbon fiber was installed to regain the strength lost from the corroded rebar. </li></ul><ul><li>The owner wanted the repaired columns to match the appearance of the other columns on this structure. </li></ul><ul><li>After the carbon fiber was installed sand was broadcast on the columns for a base to apply stucco. </li></ul>
Fatigued Members <ul><li>Central Stores </li></ul><ul><li>State Farm Insurance </li></ul><ul><li>Transwestern </li></ul>
Central Stores—City of Phoenix Situation: The wood beams that support the roof had been deflecting over a few years. The problems are exacerbated with the ponding of rain water in the dips created from the deflections. There were approximately 190 beams that required strengthening . The Owner (The City of Phoenix) wanted us to arrest any continued deflections and increase the margin of safety for the users. Challenges: Work in the space was to continue without shutting down the users. Air conditioning replacement was going on simultaneously which caused poor ventilation.
Solution: Carbon fiber laminate reinforcing with fiberglass fabric stirrups were used. The Carbon laminates provide continuous adhesive reinforcing. The laminates were placed in the middle 8' of the beams, where the deflection was the greatest on the tension face. The glass fabrics were used to eliminate shear stresses on the ends and to transfer the tensile force of the laminates up through the natural axis.
Conclusion: Arizona Repair Masons helped insure that the original engineering was adequate to meet the loads with acceptable deflection by insisting that the original calcs be checked. Workers used respirators during operations. The overstress on the beams was reduced to less than .07% and the ponds on the roof were filled in with foam to shed future water.