Performance-based seismic engineering is nowadays adopted for economical design of structures to resist earthquakes and it requires nonlinear static pushover analysis to be performed. In this approach, the energy dissipation due to nonlinear behavior of the structures is taken into account by obtaining the equivalent viscous damping and this damping is evaluated from the global pushover curve of the structures. However, the global structural damping is basically due to energy dissipation at local joints of the structures deforming beyond yield rotation. This paper presents the methodology of estimating equivalent damping from the local hinge characteristics of the structures at element level by carrying out Pushover analysis of three structures viz 3D six storeyed, 2D two storeyed and a simple column RC structure. This damping is assessed by considering cumulative hysteretic energy dissipated at all the plastic hinges developed in the structures and is compared with that calculated based on formulations given in codes such as FEMA-440 and ATC-40. Damping agrees well with that given in FEMA-440, estimated from global pushover curve of structures for ductility value greater than 3. Also, nonlinear time history analysis is performed for all the structures to validate the structural performance.

如今，基于性能的地震工程已被用于经济设计结构中以抵抗地震，并且它需要进行非线性静力推覆分析。在这种方法中，通过获得等效粘性阻尼来考虑由于结构的非线性行为而产生的能量耗散，并从结构的整体推覆曲线评估该阻尼。但是，整体结构阻尼基本上是由于结构局部接点处的能量耗散而变形，超出了屈服旋转。本文通过对三种结构进行推覆分析，即3D 6层，2D 2层和简单柱RC结构，提出了在单元一级通过结构的局部铰链特性估算等效阻尼的方法。通过考虑在结构中形成的所有塑料铰链上耗散的累积磁滞能量来评估此阻尼，并将其与根据FEMA-440和ATC-40等法规中给出的公式计算得出的值进行比较。阻尼与FEMA-440中给出的阻尼非常吻合，根据延性值大于3的结构的整体推挤曲线估算得出。此外，对所有结构进行非线性时程分析以验证结构性能。