EQUIVALENT DAMPING RATIO FOR TRILINEAR CURVES OF RC FRAMES UNDER MAINSHOCK-AFTERSHOCK SEQUENCES

Cueva J.; Kusunoki K.; Suwada H.; Diaz M.; Zavala C. · World Conference on Earthquake Engineering proceedings (2024)

Resumen

The seismic behavior of Reinforced Concrete (RC) frames, considering mainshock-aftershock (MA) sequences, has been addressed in previous studies in which the main objective is to predict the damage level after a maximum expected aftershock. This study uses numerical simulations to determine the Equivalent Damping Ratio for RC Frames and under mainshock-aftershock sequences. The Damping ratio estimation is useful to determine the Response Reduction Factor in case the Capacity Spectrum Method is applied as a Seismic evaluation procedure. In addition, this study considers the influence of the parameters that define the capacity curve in calculating the Equivalent Damping Ratio, such as the ratio of the yielding stiffness to the elastic stiffness, which presents a greater influence, and graphically represents the transition between cracking and yielding point. For that reason, in the beginning, this study presented a new expression to determine the damping ratio, which considered new reduction factor values, and a new coefficient to quantify the additional damping ratio due to the damage before the yielding point. Finally, the results show the influence of the ratio of the yielding stiffness to the elastic stiffness. For this reason, new expressions are proposed to determine the damping ratio for different hysteretic models representing the behaviour of RC Frames.

Instituciones: Universidad Nacional de Ingeniería