Wind loads, based on the velocity component approach, are defined according to API 4F Specification for Drilling and Well Servicing Structures (5th edition).
The API 4F specifications for wind loads based on the velocity component approach is integrated into the PSE Petroleum Structural Engineering software. Accordingly, drilling structures are classified based on their Structural Safety Level (SSL) and their offshore or onshore location.
The design reference wind velocity Vref value chosen should be a 3-second gust wind measured at an elevation of 10 m (33 ft) in open terrain or water, with an associated return period of 50 or 100 years.
The Petroleum Structural Engineering® software has a tool to generate wind and ice loads on open structures such as drilling structures. It allows generating automated ice loads or wind loads on each element of the structure.
The PSE software automates wind loads applied to members. These loads are calculated based on the projected area, projected pressures or velocity components approaches. The program offers a variety of wind profiles and automates the determination of the shape coefficients (drag factors).
The API 4F specifications are applicable to the following wind environments:
A wind profile in a selected direction provides the wind intensity that generates the wind loads to structural members and surface areas. As many as required wind directions can be defined through different basic loads.
Member selection procedures allow the application of the wind profile to the entire structure or to specific zones and excluding members behind or in front of wind walls. It is possible to apply the API 4F wind loads directly to elements such as equipment, wind walls and other objects attached to the drilling structures.
The shape coefficient (Cs) is automated in the PSE software for various section shapes. The program accounts for the gust factor (Gf) and the reduction factor for shielding (Ksh) for members and appurtenances.