Retrofit Concrete Structures with CFRP
The need to retrofit existing reinforced concrete structures has increased over time due to corrosion of the steel reinforcement inside the concrete and increased loading. Experimental and numerical studies in this field show that using carbon fiber reinforced polymer is an effective method of reinforcement as it increases shear strength in concrete structures. This strengthening technology has numerous advantages over conventional steel plating, such as providing high strength-to-weight ratio, versatility, durability, and ease of install. Orienting carbon fiber reinforced polymer fibers transverse to the axis of the member or perpendicular to potential shear cracks is effective in providing additional shear strength.
Two carbon fiber reinforced polymer shear strengthening wrap schemes are commonly used: U-Wrap and Full-Wrap. U-Wrap is more commonly used than Full-Wrap in shear strengthening of reinforced concrete structures in North America since U-Wrap provides excellent reinforcement that often meets or exceeds project specifications. Studies have shown that a U-Wrap can increase the shear capacity by more than 100%. Full-Wrap is more labor-intensive and typically used for seismic reinforcement where higher strength is required.