SEISMIC PERFORMANCE EVALUATION OF EXISTING RC BUILDING USING BRACED STEEL FRAMES

Earthquake is a natural disaster that destroyed the large property and two deaths with many injuries during this decade, occurring at the northern of Thailand. By this cause, this paper aims to evaluate the performance level of existing reinforced concrete building by retrofitting with the braced steel frames. Moreover, a three-story building is analysed in SAP2000, used the Nonlinear Static Procedure Method. Therefore, three different methods are chosen to study in this paper. The first of all, Displacement Coefficient Method presented in ASCE/SEI 41-13 and FEMA 440, used to calculate target displacement to point out building performance levels. The second method, Capacity Spectrum Method published in ACT 40, used deformation limits to compare with total roof displacement ratio (Δ roof top /H) at the performance point to classify various performance levels. The last one, The ASCE/SEI 41-13 uses plastic rotation limit criteria to compare with maximum plastic hinge rotation for member evaluation of the RC frames. According to the result before retrofitting, the first and second methods meet Life Safety (LS) and Immediate Occupancy (IO) levels, respectively. The third method of this paper separated into column and beam performance levels which meet performance levels in both Life Safety (LS) levels. From the experiment, It shows that if we use the concentrically braced steel frames to retrofit the structure, it will lie in Immediate Occupancy (IO) level for all of the methods. Furthermore, the construction works of outer steel frames do not stop the function of the buildings.