Dynamic Response Analysis Of Model Parameters And Loads For Important Structures

Offshore platform and nuclear power plant are important structures, thinking of the effect of material parameters, or the randomness of loading is very necessary. Offshore platform is always in a relatively poor natural environment, the impact of seismic earthquakes and waves are more significant, so uncertainty analysis of loading for platform is made; Nuclear power plant usually is located at the load relatively stable region, therefore, model uncertainty analysis of materials for nuclear power plants is made. With thinking of uncertainty analysis of nuclear power plant structure, provides an evaluation for the certainty of floor spectra. Summary details are as follows:(1) Two kinds of FEM models considered equivalent pile, and spring-damper pile respectively were founded by means of the software ANSYS. The focus is to simulate the interaction through the spring damper elements. Analysis and comparation of the response spectrum on the platform point are made, the result shows that the spring-damper pile modal can simulate the pile-soil interaction better than the equivalent pile modal.(2) In order to reflect the impact of uncertainty in the calculation of various parameters, ASCE Standard indicates that peak of the floor response spectrum deduced by the deterministic method may be broadened and reduced, In order to provide technical basis for the reasonable peak broadening and reduction, the probabilitic-statistical analysis of the floor response spectrum is madeâ‘ under the determination of the level of input ground motion and the uncertainty of model parameters orâ‘¡under the determination of model parameters and the uncertainty of input ground motion. The results indicate that the peak of floor response spectrum is not only more smoothing but also smaller after the probabilitic-statistical analysis.(3) Floor spectrum is the basis for seismic design of structures. There're generally two groups of methods for computation of floor spectrum. The first group includes time-history analysis methods, characterized by transient analysis with earthquake time-history input as excitation. While the second group includes the so-called direct methods, where the floor spectrum is calculated from response spectrum of input ground motion directly. Focusing on the second group, comments on several direct methods including the ones proposed by Biggs, Kapur and Singh have been made. Based on the work of Biggs and Kapur, a revised modal method is presented. Dynamic soil-structure interaction effect is taken into consideration. The computation can be easily carried out and the result obtained is highly reliable.