February, 2006
Feature
Inspection News and Views from the American Society of Home Inspectors



Meet The Reinforcer®

BOB THOMPSON, PE

Whether in a residence or a commercial building, in most cases, the best defense for foundation failure is a good offense. The development of The Reinforcer®, a recently REINFORCER-blk.gifpatented carbon fiber technology system, is providing an alternative for repairing and strengthening foundation walls. Developed by Nationwide Reinforcing, Ltd. (Columbus, Ohio), the externally bonded composite reinforcing system is a Carbon Fiber Reinforced Polymer (CFRP) that is lightweight, non-corrosive and virtually impossible to stretch. The carbon fibers form in an epoxy resin matrix that has a tensile strength of more than 350,000 pounds per square inch (psi), making it 10X stronger than steel, which has a tensile strength of 36,000 psi.   

To date, the process of installing steel beams with heavy equipment (digging, jackhammering, moving utilities and duct work, etc.) has been the primary way to brace and shore up existing foundation walls. The Reinforcer® is essentially a carbon fiber “strip” or “strap” that is only 4" wide and .045" thick, making these old and intrusive methods appear antiquated.

Design/Engineering Philosophy

BOWINGPC.gifA foundations’ structural integrity becomes jeopardized when hydrostatic and lateral earth pressures exceed the strength of the concrete or masonry wall. These lateral pressures barrage the foundation and cause the walls to bow inward. The philosophy behind The Reinforcer® is based on standard engineering principles following Hookes law and a linear stress strain relationship. (Illustration: A foundations’ structural integrity becomes jeopardized when hydrostatic and lateral earth pressures exceed the strength of the concrete or masonry wall.)

REINFORC.gifFor every increase in pressure, The Reinforcer® provides an equal and opposite resistant force; making the wall stronger, which helps eliminate shifting, cracking and bowing.

Being lightweight and thin-as-a-dime, it is easier and faster to install. We believe this is particularly beneficial around complex plumbing and electrical systems that otherwise might have to be removed  and reinstalled. It’s also an attractive solution. Once the block wall has been painted over, it is virtually concealed. (Illustration: For every  increase in pressure, The Reinforcer®
provides an equal and opposite resistant force; making the wall stronger.)


Streamlined Installation  

Using-roller.gifThe installation process is simple, and it takes approximately half the time other solutions take; therefore, it is cost-efficient. The high-strength carbon strips are supplied on 250 ft. continuous rolls, cut-to-length, and spaced based on the engineering design charts prepared by Nationwide Reinforcing’s engineers.


Better-Way.gifThe walls must be cleaned of all paint and debris prior to installation. The strips are then applied with a structural epoxy paste (ECS 104) along the interior surface of the bowed or cracked walls. Removing excess epoxy off the strips and filling remaining cracks with ECS 104 completes the installation.



Residential Advantage

Foundation failures represent a stigma (both real and perceived) for homeowners who fear the real estate value of their home and its structural integrity may be compromised. Certified installers have completed more than 20,000 residential Reinforcer® installations across the United States and Canada.      

Commercial Advantage

As competition and technology continue to converge, engineers and contractors are seeking out material alternatives such as Fiber Reinforced Polymers (FRP), over conventional steel and wood for construction applications. This trend is based on a variety of design flexibility and material performance advantages; i.e.—lighter weight, easier installation, higher strength and the non-corrosive ability to withstand harsh environments.

Advancing this trend, The Reinforcer® carbon fiber strengthening system is being used for commercial construction applications from bridge decks to parking garages, from culverts to stadiums. The product’s inherent material performance benefits allow the construction industry to comply with increased design load specifications and keep ahead of ever-changing Code requirements.  

Manufactured and distributed by Nationwide Reinforcing, Ltd. since 1998, the system comes with a lifetime manufacturer’s warranty. The company also produces a unidirectional sheet/fabric made with high-strength carbon or glass fibers called The Reinforcer ShieldTM. This product can conform to irregular shapes such as circular or square columns. It’s used for flexural and shear strengthening and can provide a waterproofing membrane for foundation walls.

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Home Inspectors question: Manufacturer answers

Q. Is The Reinforcer® only for concrete block foundations?

A. The system is also for poured, brick and other cement/masonry foundations; not just block: although that tends to be the primary application.

Q. Can it be installed on a significant wall deflection (buckled) to prevent further movement? All of the photos showed walls that appeared to be plumb. You know that residential sellers & buyers usually operate on minimal budgets and would like to keep what they’ve got structurally, even if it is cosmetically undesirable.

A. The Reinforcer® is used 99 percent of the time on walls or structures that have already bowed or cracked. Seldom do we do a true preventive maintenance installation.

Q. Can it be used where the concrete surface isn’t sound; if the concrete sloughed?

A. The concrete and block need to be solid, not deteriorated or falling apart. We have performed nearly 20,000 projects and only turned away 5 to 10 jobs that had severe deterioration.

Q. Can it be used on surfaces that have been painted or coated with something like waterproofing paint or anything else that might interfere with the bond? Or do coatings have to be sandblasted off the surface before the system is applied?

A. We use a specialized surface grinder on nearly every job to remove paint or waterproofing materials. This is standard and easily performed at minimal cost. One person can usually prepare the area in approximately 5 minutes. We will sandblast on outside projects like bridge decks or parking garages where the mess doesn't matter.

Q. The literature states this approach is cheaper than conventional repairs. Most repairs of this type must be engineered; is there an engineering expense with The Reinforcer® system? 

A. Nationwide Reinforcing provides free engineering consulting on all jobs, and works directly with our certified installers to train them and educate the local engineers on our system.

Q. Apparently the product has already been used in my state with architectural/engineering and code approval on public buildings, which take on the most liability. What, if anything, do you know about local codes and this product?

A. It has been used in most states and Canada with the approval of local engineers and building codes. For instance, Columbus and Cleveland, Ohio, have approved it. Most municipalities recognize us as a proven system as long as a structural engineer stamps the plan.Manufacturer answers
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PENN STATE’S NEW $30 MILLION BEHREND COLLEGE FACILITY SOLVES STRUCTURAL BOND BEAM FAILURES

PROJECT PROFILE / CHALLENGE:  As construction was nearing completion at Penn State Erie, The Behrend College’s $30 million Research and Economic Development Center (REDC), inspectors revealed a foundation failure that had to be addressed economically and immediately given the projects’ 2006 completion target.  During construction, the bond beams at the corners of the structure were not properly installed; rebar placed on wrong face, wrong size bar, jumping from cell-to-cell, etc.

Located on a 725-acre campus and home of the School of Business and the School of Engineering and Engineering Technology, the 160,000-square-foot, state-of-the-art facility was designed by the architectural firm Weber Murphy Fox of Erie and NBBJ of Columbus, Ohio. Addressing the foundation failure dilemma head-on, the architectural firms engaged the project’s structural engineering sub-contractor, Urban Engineers, Inc. (Philadelphia, Pa.) to  analyze the situation and find an  efficient solution to correct the  deficiencies in the existing bond beams. 

According to Urban’s project engineer for REDC, Dave Steele, “Traditional options were tearing down and restructuring the wall, or to thread rebar, re-grout solid and tooth-out the end of the wall to try and rebuild it. These options were not acceptable given the project’s schedule and budget considerations.”

Steele contacted the engineers at Nationwide Reinforcing to explore the viability of a patented carbon fiber strengthening system they manufactured. Urban provided Nationwide with engineering data of loads that had to be met and the system—The Reinforcer-- exceeded all criteria.

ENGINEERED SOLUTION: 

Bob Thompson, co-founder of Nationwide Reinforcing Ltd. and also a professional civil engineer, worked with Urban Engineers on the engineering design to provide optimal placement of The Reinforcer strips during the project’s installation. Thompson said, “The solution we came up with was to install (2) 50-foot long strips in each corner (interior and exterior) of the structure to strengthen the deficient bond beams. By placing two strips side-by-side, we were able to reach capacity based on the load requirements.” 

As the architectural design’s master plan was to enhance and preserve the beauty of Penn State Erie's campus, The Reinforcer® also provided an aesthetic advantage. According to Steele, “The product has a high capacity and a thin profile which was huge for the architecture’s (painted block) aesthetics because it created a seamless look.”
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RETIREMENT LIVING FACILITY RESOLVES FOUNDATION FAILURE WITH CARBON FIBER TECHNOLOGY SYSTEM 

 PROJECT PROFILE:  Wellington at Hershey’s Mill (East Goshen Township, Pa.) is a recently constructed, 370,000 square foot retirement facility that offers 195 independent living senior apartments. As construction on the multi-story project was nearing completion, and many of the residents had already moved in, building code inspectors uncovered a structural deficiency that would jeopardize the licensing agent to sell units above the parking garage of the $21,000,000 facility. During the new construction phase, the reinforcing steel in the below grade walls was placed in the center of the wall instead of near the interior face of the wall per the engineering design. This error rendered the facility’s 90,000 square foot underground parking garage structurally deficient. 

The deficiency had to be resolved quickly. The general contractor and the licensing and inspection engineering group looked for alternative options to steel I-Beams or costly and time-consuming demolition and reconstruction of the garage’s foundation walls.

OPPORTUNITY/ CHALLENGE:  The general contractor contacted John Ferguson, Premier Building Restoration, to explore retrofit options to correct the deficiencies in the existing parking garage walls and meet the codes. Ferguson’s firm had been using a carbon fiber strengthening system called The Reinforcer® in many residential and commercial projects and contacted the product’s manufacturer to explore its viability as a retrofit solution for the retirement facility. The externally bonded strengthening system is essentially a 4” wide and .045” thick “strip” or “strap” made of Carbon Fiber Reinforced Polymer (CFRP). The material is lightweight, non-corrosive and virtually impossible to stretch; having a tensile strength of more than 350,000 pounds per square inch (psi):  making it 10X stronger than steel (36,000 psi). Bob Thompson, co-founder of Nationwide Reinforcing Ltd., brought in his team of independent structural engineers to conduct approximately 20 hours of engineering analysis of the project. The analysis included verifying lateral loads, height of the walls and properties of the masonry and grout to design the spacing for The Reinforcer.

According to team member Bill Shelley, president of Shelley Metz Baumann Hawk, Inc., “These variables were used in an ultimate strength design vs. a working stress methodology, which gave us a better representation of the existing wall’s strength and assumes certain failure mechanisms to assure adequate measure of safety.”

According to Ferguson, “The documentation and calculations Nationwide provided to the township engineer essentially proved that The Reinforcer® would work and was the optimal solution for the application.”

INSTALLATION/CONCLUSION:
The engineers prepared engineering design charts of the 400foot area of below grade walls that were over stressed. The charts allow certified installers to effectively determine the number of high-strength carbon strips needed and the optimal spacing required on the 11’-to-15’ tall walls. Since the retirement facility was occupied, installation had to occur with the least amount of interruption to residents’ daily activity. Therefore, the installer worked in sections to minimize disruption.  Because of the pending occupancy licensing deadline, the project had to be fast-tracked.  Since this system requires no digging, jack hammering, moving utilities or ductwork, the installation process takes approximately half the time of other methods. Installation was completed in two days, which satisfied the township as well. Approximately 100, pre-cut, 8’ Reinforcer® strips were applied with a structural epoxy paste (ECS 104) along the interior surface of the foundation walls.

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