EARTHQUAKE AND WAVE DESIGN CRITERIA FOR OFFSHORE PLATFORMS

A method that applies experience, projections of environmental conditions, response analyses, and reliability logic is used to develop earthquake and wave design criteria for one class of offshore platform system. The system consists of a steel, tubular-membered, template-type superstructure supported on piles and firm soils, in 300 ft of water. Three fictitious sites are considered: Eastern Gulf of Alaska, Southern California, and the Santa Barbara Channel. Ranges of design wave heights and ground motion velocities are given. Results are compared with those appropriate for a conventional building structure and with those from API RP 2A guidelines for fixed offshore platforms. Good agreement with API guidelines is indicated.