ULSLEA: A Limit Equilibrium Procedure to Determine the Ultimate Limit State Loading Capacities of Template-Type Platforms

Abstract

During the past three decades, an immense amount of effort has been devoted to development of sophisticated computer programs to enable the assessment of storm wind, wave, and current loadings and the ultimate limit state capacity characteristics of conventional, pile-supported, template-type offshore platforms (Billington et al, 1993; Frieze, 1993; Hellan et al., 1993, 1994). These programs require high degrees of expertise to operate properly, are expensive to purchase and maintain, and require large amounts of manpower and time to complete the analyses. Due to the sophistication of these programs, experience has shown that it is easy to make mistakes that are difficult to detect and that can have significant influences on the results. This paper summarizes the second phase of development and verification of simplified procedures to evaluate environmental loadings and ultimate limit state lateral loading capacities of template-type platforms. Reasonable simplifications and high degrees of user friendliness have been employed in development of the software to reduce the engineering effort, expertise, and costs associated with the analyses. The computer program that has been developed to perform the simplified analyses has been identified as ULSLEA (ultimate limit state limit equilibrium analyses) (Mortazavi and Bea, 1994).