| This study proposes both steel and fiber-reinforced polymer(FRP)composites as main reinforcement for modern moment-resisting frame structures.The design concept of the proposed reinforcement detailing is stated based on the available provisions of the current seismic-design codes.A very detailed 3D FEM model,which takes into account the material and geometric nonlinearity and bond behavior of the steel and glass FRP(GFRP)reinforcement,was created and validated against the available experimental results.54 cases covering all possible combinations of steel-to-GFRP reinforcements(both under and over reinforced design scenarios)were studied.The analysis results of SFRC joints pointed to the ratio between the effective FRP reinforcement ratio and the balanced FRP reinforcement ratio(the normalized reinforcement ratio)as the main design tool that can be adopted to achieve the required seismic behavior;and a definition is given to the lower and upper limits of the normalized ratio.Design recommendations regarding the controllability of the serviceability state,the post-yielding state,the residual strength,and the ultimate state of SFRC joints through an appropriate design for the steel-to-FRP reinforcement ratio are drawn.Finally,a mechanical model describing the behavior of SFCR joints with different steel-to-FRP reinforcement ratios is introduced based on the general behaviors of the simulated joints. |
PDF Full Text Request