Design of flexural strengthening based on fib Bulletin 90

Abstract

This paper presents the analysis of intermediate and end debonding failure in slab strengthened using carbon tapes (Carbon Fiber Reinforced Polymer). The calculations are based on the more accurate method in the latest fib Bulletin 90. Consideration of additional effects based on three conditions: basic bond, bond friction and member curvature in the intermediate crack debonding analysis give the ratios ΔFf Ed/ΔFf Rd from 0.01 to 0.11, depending on the cross-section. For comparison in the simplified analysis of the ratio, MEd/MRd is equal 0.76. It is clearly visible the methods requiring more computational effort give lower values of element effort and allows the design to be more economical. As the strengthening fulfills the ultimate limit state, it does not meet the serviceability limit state.

Keywords

• externally bonded reinforcement (ebr)
• fiber reinforced polymer (frp)
• flexure
• strengthening
• load capacity