Flexural Strengthening of Steel Bridges and Towers Using High Modulus CFRP Materials

Many steel structures are in need of strengthening due to reqUirements to increase carrying capacity and/or rehabili tation due to corrosion degradation. This paper summarizes the results of an investigation that has been conducted to evaluate the performance of carbon fiber reinforced polymer (CFRP) materials to increase the strength and stiffness of steel structures. Two types of specimens were used: monopole towers and steel-concrete composite g irders representative of typical steel bridges. Three sleel monopoles, scaled from those typ ically used by the telecommunicat ions ind ustry, have been strengthened using different schemes. The first monopo le was strengthened by wet lay~up of high modulus unidirectional CFRP sheets that conformed to its dodecagonal cross-section. The remaining monopoles were strengthened using CFRP stri ps bonded to the flat sides of the monopoles using two different types of fiber. This paper also includes the results of a steel-concrete composite g irder strengthened on the tension side using externally bonded internlediate modulus CFRP strips. The remaining girders will be strengthened using high modulus CFRP strips in two different configurations including one prestressed configuration. The results of these two girders will be presented at the conference