Chad Slowthower, Graduate Student

Department of Civil & Environmental Engineering

The Pennsylvania State University

ABSTRACT

In recent years, the near failure behavior of jacket platforms has become a particularly important interest to the offshore community due to extreme environmental events such as Hurricane Andrew. The static ultimate strength of offshore jacket platforms may be exceeded by peak wave loads during extreme storm events such as Hurricane Andrew. In such a loading environment, a static analysis would predict collapse, although a structure may be able to resist these overloads dynamically if the load is limited in duration and the structure has sufficient inertial resistance and ductility capacity. The principle objective of this work is to study the non-linear dynamic response of jacket platforms in the extreme multiple wave load environment. In essence, we will utilize the results from 3-D static pushover analysis to simplification because the platforms vibrate in the primary mode shape so knowing the displacement at any level will set the structural configuration. The non-linear dynamic capacity will be estimated for the jacket platforms, given the displacement capacity of the platform, in the extreme multiple wave load environment. The results obtained from the multiple wave loading will be compared to those obtained for a single wave loading to demonstrate how the response changes or is similar when considering multiple wave load effects. This study will also examine the effects of the overloading ratio, force-deformation curves, damping, periods of the waves, and natural period of the structure on the non-linear dynamic force/wave capacity. We will examine several variations of a platform to try to draw some generalized conclusions.