Flexural capacity analysis for strengthened concrete beams side-bonded with prestressed CFRP plates

To obtain the calculation formulae for predicting the normal section flexural capacity of the strengthened concrete beams side-bonded with prestressed CFRP plates, two possible failure modes of the strengthened beams (concrete crushing and CFRP plate rupture) and the relevant discrimination methods were proposed in this paper. Considering the reduction of CFRP plate area because of side bonding, the calculation methods for flexural capacity of the two failure modes were presented based on analysis of the ultimate state of sections. To verify the proposed formulae, experimental studies on four concrete beams strengthened with prestressed CFRP plates on its vertical sides were carried out using the self-developed tensioning and anchoring equipments for the CFRP plate. Experiments show that the failure modes are consistent with the calculated results. The calculated values of flexural capacity agree well with the experimental results. A practical design method for the strengthened concrete beams side-bonded with prestressed CFRP plates was proposed, which can provide a reference for engineering application of strengthening design, especially applicable for the structure when there are some obstructions underneath.