This paper summarizes results of a study performed to requalify for continued service the Arenque platforms located offshore Tampico, Mexico. Hurricane and earthquake environmental conditions were included in the requalification study. The evaluations of suitability for service included Allowable Stress and Ultimate Limit State criteria. The background for the hurricane and earthquake conditions, criteria, and guidelines are detailed in a companion paper (Bea, et al, 2000).
An analysis of the loadings and performance of the Arenque platforms has been provided by American Bureau of Shipping (ABS, 1994a, 1994b, 1994c) and by the Instituto de Mexicano del Petroleo (IMP, 1996) The purpose of this paper is to use these previous results to develop an example application of the risk based hurricane and earthquake criteria to the Arenque A platform (Fig. 5.1), located due East of Tampico.
The example Arenque A platform (Fig. 2) was originally designed, constructed, and installed by J. 1L McDermott International Inc. in 1970 in a water depth of 54.7 m. The platform was designed according to the first-generation API RP 2A guidelines (1969). The oceanographic criteria for the platform design was provided by A. H. Glenn (1969) and consisted of a 100- year design wave height of Hm100 = 17.3 m and no currents. The site soil borings (Fugro-McClelland Marine Geosciences Inc., 1996; LIAC 1968) indicate that the soils are layered soft to strong calcareous clays and sands with an average undrained shear strength of approximately 90 kPa to a penetration of about 22 m (Fugro-McClelland Marine Geosciences, 1996; LIAC, 1968). Calcareous sands of moderate density underlie the upper layer of cohesive clays to a penetration of approximately 193 m. The platform is a conventional template-type steel 8 pile batter leg platform with two decks.