Study On Optimization Design Of Prestressed HFRP Strengthening Beams’ Bending Performances

Prestressed FRP sheet used in structure strengthening is a new type of reinforcement technology.In this thesis strength evaluations for steel and steel reinforced concrete (RC) beams whichstrengthened with hybrid fiber reinforced plastic (HFRP) were studied. Upon with them, HFRPoptimization design strategies were suggested. The main contents are as follows:1. Based on the current normal section bending bearing capacity theory for I shaped steel beam,formulas for flexural capacity for the beam strengthened with pre-stressed single type fiber FRP(or inter-layer HFRP) were deduced. Then, according to the loads evaluating requirement, aHFRP optimization design model was established. In this model, the objective function is theengineering cost while the restrain condition is the flexural strength of the beam. Thisoptimization approach has been implemented based upon software of MATLAB.2. Normal section bending bearing strength evaluations both for beam reinforced with pre-stressedHFRP before and after carrying loads were suggested, base on the existing design code. Further,HFRP optimization design strategy, aiming to reduce cost and meanwhile satisfying strengthrequirements, were modeled. It has been also implemented upon MATLAB.3. The above optimization approaches were employed to the optimization HFRP strengtheningdesigns for typical steel and RC beams, respectively. Three dimensional finite element modelswere also built to simulate the strengthening process and it validated the theoretical optimizationapproach.