To reveal the effect of P-Δ on the residual displacement ductility demand of structures, the damage-based residual displacement ductility demand ratio spectrum μres of single degree of freedom (SDOF) systems was conducted based on the Park-Ang damage model. The data were statistically processed to evaluate the effect of soil type, elastic stability coefficient θ, ultimate ductility coefficient μu and hysteretic model on damage-based μres. A prediction equation was proposed to estimate damage-based μres of SDOF systems through regression analysis. The differences of μres based on damage approach and ductility approach were compared and analyzed. Results show that the error in the estimation of damage-based μres when mean values along the earthquake population are considered without any soil distinction is inside 10%. When the P-Δ effect is not considered, the influence of μu on damage based μres exceeds 20%. When the P-Δ effect is considered, the influence of μu on damage based μres exceeds 50%. The ductility-based μres tend to be conservative compared to the damage-based ones. Finally, the prediction equation for the estimate of damage-based μres is proposed, which can be applied to the evaluation of residual displacement ductility demand ratio and seismic resilience.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |