What is basement wall grade carbon fiber? We have all heard of it being used for race cars, NASA ships, and tennis rackets, but basement wall reinforcement? Why would it be used in foundation repair applications?
Carbon fiber is lightweight, noncorrosive, and virtually impossible to stretch. With a tensile strength of more than 350,000 psi, it is up to 10 times stronger than steel. Accordingly, high-quality carbon fiber provides an alternative to such intrusive methods as installing steel beams with heavy equipment to brace and shore up foundation walls: no digging, jackhammering, and moving utilities and ductwork are required.
A foundation's structural integrity becomes compromised when hydrostatic and lateral earth pressures exceed the strength of a concrete or masonry wall. As lateral pressures press upon the foundation, basement or crawl space walls bow inward. Its effectiveness in counteracting such tendencies is based on standard engineering principles following Hookes law and a linear stress/strain relationship. For every action there is a reaction, the action is the soil pressing on the basement wall and the reaction is the carbon fiber applying a resistant force, making the wall stronger to help eliminate shifting, cracking, and bowing.
One of the other big benefits of carbon fiber is its ease of use and aesthetics. You will not have I-beams lined across the basement wall. The thin layer of carbon fiber material can be painted over without creating an eyesore. Ductwork and plumbing penetrations can be left alone due to its flexible nature.
In most residential situations where bowing basement walls occur there are several sets of forces which interact to cause the problem. The largest mobilizing force is the addition of lateral earth pressure (soil forces) in conjunction with hydrostatic pressure (water forces). These forces put a horizontal load on the wall which in turn creates a large amount of bending stresses on the masonry or concrete. The bending stress creates an unbalanced condition within the wall due to the very low tensile capacity of concrete and masonry, causing horizontal cracking in the structure. The weight of the structure above the wall helps generate a stabilizing compressive force on the wall until the lateral deflections become too large. As the wall deflects beyond the "center of mass" of the above structure a phenomenon known as the "beam-column effect" creates additional bending stresses on the damaged wall, speeding up deterioration. Carbon Fiber Reinforced Polymers (CFRP's) provide the required additional tensile force needed to fully develop the compressive strength and create a "balanced" situation within the wall to prevent further bowing and cracking.
Carbon fiber fabric is placed over basement wall cracks to provide strength to the cracked area. No drilling is necessary as with other crack repair systems. The advantages of using carbon fiber fabric to repair wall cracks are:
ECP Carbon Fiber products provide our customers with a durable, high strength, and aesthetically appealing fix to the common problem of bowing basement walls. The repairs are waterproof and can enhance the flexural capacity of steel reinforced and un-reinforced masonry walls the original capacity. The high stiffness of these carbon-based products can stop lateral wall movement virtually instantaneously without the problems associated with steel alternatives including corrosion, aesthetics, obstructions, and lower strength capacities. The epoxy polymers used to bond the carbon fiber systems to your basement wall have been successfully tested over 20,000 hours of continual exposure to resist chemicals, temperatures, and moisture much more aggressive than typical basement environments assuring a long-term repair.