SEISMIC STRENGTHENING OF R/C FRAME STRUCTURES USING PERFORMANCE BASED DESIGN APPROACH Zdravko Bonev and Stanislav Dospevski 1 65 th anniversary Faculty of Hydraulic Engineering University of Architecture, Civil Engineering and Geodesy - Sofia

2 65 th anniversary Faculty of Hydraulic Engineering University of Architecture, Civil Engineering and Geodesy - Sofia Performance Based Seismic Design GENERAL IDEAS AND APPROACHES FOR APPLICATION

3 65 th anniversary Faculty of Hydraulic Engineering University of Architecture, Civil Engineering and Geodesy - Sofia Fig. 1. Loading patterns for vertical and horizontal forces PBSD based on static pushover analysis APPLICATION OF CSM AND N2 METHODS

4 65 th anniversary Faculty of Hydraulic Engineering University of Architecture, Civil Engineering and Geodesy - Sofia Fig. 2. Determination of actual capacity spectrum from pushover curves: actual (dashed line) and idealized (solid line) STATIC PUSHOVER ANALYSIS: RESULTS ON OUTPUT – CAPACITY CURVE AFTER USING SINGLE MODE ANALYSIS

5 65 th anniversary Faculty of Hydraulic Engineering University of Architecture, Civil Engineering and Geodesy - Sofia DERIVE DESIGN CAPACITY SPECTRUM FROM CALCULATED CAPACITY SPECTRUM Design concepts considering opening of the plastic hinges Consequent opening with redistribution

6 65 th anniversary Faculty of Hydraulic Engineering University of Architecture, Civil Engineering and Geodesy - Sofia DERIVE DESIGN CAPACITY SPECTRUM FROM CALCULATED CAPACITY SPECTRUM Design concepts considering opening of the plastic hinges Simultaneous opening without redistribution (the most unfavourable release mechanism)

7 65 th anniversary Faculty of Hydraulic Engineering University of Architecture, Civil Engineering and Geodesy - Sofia DERIVE DESIGN CAPACITY SPECTRUM FROM CALCULATED CAPACITY SPECTRUM overstrength factor

8 65 th anniversary Faculty of Hydraulic Engineering University of Architecture, Civil Engineering and Geodesy - Sofia Fig. 4. Determination of target capacity spectrum using base shear force – roof displacement relationship DETERMINATION OF TARGET DISPLACEMENT USING CSM IN CONJUNCTION WITH N2 METHOD

9 65 th anniversary Faculty of Hydraulic Engineering University of Architecture, Civil Engineering and Geodesy - Sofia Different strengthening techniques FRP R/C jackets use of steel framework Techniques for increasing the elastic stiffness and yield strength

10 65 th anniversary Faculty of Hydraulic Engineering University of Architecture, Civil Engineering and Geodesy - Sofia Fig. 5. Comparison between e ACS-1 with TCS and ACS- 2 with TCS ANALYSIS OF NEED AND BENEFIT OF STRENGTHENING (design capacity spectrum DCS is denoted as target capacity spectrum TCS) ACS are determined through NONLINEAR STATIC (PUSHOVER) APPROACH using material data for the structure.

11 65 th anniversary Faculty of Hydraulic Engineering University of Architecture, Civil Engineering and Geodesy - Sofia ANY QUESTIONS ? THANK YOU FOR YOUR KIND ATTENTION !