NEHRP Clearinghouse
- Title
- Reliability Assessment of Offshore Platforms in Seismic Regions.
- File
- PB288572.pdf
- Author(s)
- Yang, J. N.; Freudenthal, A. M.
- Source
- National Science Foundation, Washington, DC. Applied Science and Research Applications., August 1977, 118 p.
- Identifying Number(s)
- TR-2
- Abstract
- The purpose of this study is to present a method of reliability analysis and design for the offshore platforms under stochastic dynamic loads during their design service life. The present approach combines the analyses of nonlinear random vibration and the first passage probability, and is more accurate than the conventional equivalent static or quasi-static design procedures. The reliability design is then examined to establish the conditions under which the design for one loading condition, such as storm waves is sufficient, as well as the conditions under which both the storm waves and the earthquakes are given equal emphasis. The applied loads due to storm waves and earthquakes, are modeled as stationary Gaussian random processes with zero mean and finite duration. The importance of the earthquake design relative to the storm wave design is expected to increase as the water depth decreases. It is further shown that the nonlinear drag force is extremely important in the design of deep offshore platforms.
- Keywords
- Statistical distributions; Earthquake resistant structures; Dynamic loads; Offshore structures; Seismic waves; Earthquake engineering; Random vibration; Ocean waves; Design criteria