Analysis of the stress intensity factor of vertical cracks in small-size beams bonded with GFRP

摘要

At present, the technique to strengthen reinforced concrete (RC) beams through bonding glass fibers reinforced plastics (GFRP) is widely used in civil engineering and the effects are satisfactory. In the view of fracture mechanics, the essence of the GFRP bonding technique is to reduce the stress intensity factor of vertical (flexural) cracks in concrete and then retard the propagation of those cracks. Aimed at small-size beams bonded with GFRP, with the finite-element method, the paper analyzes the varying tendency of the stress intensity factor of vertical cracks with the change of GFRP thickness, flexural crack length and peeling-off length of bond interface in beams. The work is helpful to the decision of GFRP thickness, the plan of bonding operation and the choice of bond glues in strengthening RC beams with bonded GFRP cloths, and is theoretically and practically referential to the development of the bonding technique.