基于地震时程法的导管架平台动力响应分析

Seismic Dynamic Response Analysis of Offshore Jacket Platforms Based on the Time History Analysis Method

基于渤海海域某导管架平台,采用响应谱法和时程分析法分别进行平台地震动力响应计算。通过对比不同地震动强度下的结构响应及变形,探讨2种分析方法对平台抗震性能的影响,评价二者在工程实际中的适用性。研究结果表明:在地震较小(弹性抗震阶段)时,2种方法均可很好地预测平台的动力响应;常规响应谱法由于计算效率高,可作为平台抗震分析的工程手段,但当地震逐渐增大(弹塑性抗震阶段),响应谱法的结果相对保守,而地震时程法在评估结构非线性性能以及充分利用材料塑性能力上有明显优势,因此可在工程中作为强震下导管架平台抗震性能评估的有效方法。

Two analysis methods,i.e.,the response spectrum analysis method and the time history analysis method,are utilized for the seismic design on an offshore jacket platform in the Bohai Sea.By comparing the structural response and deformation under different ground motion intensity,the influence of two analysis methods on the seismic performance of the platform is discussed,and the applicability of the two methods in engineering practice is evaluated.The results indicate that when the seismic level is low(the structure deformation is in the elastic stage),both of the two methods can well predict the dynamic response of the platform.Due to the high computational efficiency of the response spectrum method,it can be regard as the seismic design method in the engineering.However,when the spectral acceleration gradually increases(the structure deformation is in the elastic-plastic stage),compared with the response spectrum method,the time history analysis method should be used to evaluate the dynamic response of the structure since it can make full use of the plasticity of material.It is possible to regard the time history analysis method as an effective way for seismic response analysis of offshore jacket platforms under high-level earthquakes.