API TR 2A-LFS-2020

The American Petroleum Institute (API) published the 1st Edition of the Load and Resistance Factor Design (LRFD) guideline, i.e. API 2A-LRFD (1993), in 1993 after about 10 years development and calibration work through the 1980s. The LRFD-format was intended to improve the conventional Working Stress Design (WSD) format in the following ways (Lloyd and Karsan 1988, Moses 1981, Moses and Russell 1980, Moses 1986, and Moses and Stahl 2000): (1) produce more uniform reliability levels by using load and resistance factors that account for the relative variability in the load and resistance; (2) provide greater flexibility to incorporate new technological findings and extend existing experience to new geographic areas and new platform types; and (3) keep pace with modern code development in other engineering applications.

Although API 2A-LRFD (1993) was widely recognized and had a significant influence on the development of the International Standard ISO 19902, it was not used commonly in the United States and was withdrawn in 2012 due to a lack of maintenance. API 2A-LRFD was re-introduced in 2014 as a draft 2nd Edition in an effort to align and merge the API and ISO standards as a single global standard (Ku and Farrel 2014). The motivation for this study is to evaluate the suitability of the load factors in API 2A-LRFD (1993) given the accumulated experience since the 1980s about hurricane hazards and platform performance.