Safety Factors Evaluation for Torpedo Anchors Design

Abstract

The use of powerful numerical tools based on the finite element method has been
improving the prediction of the ultimate bearing capacity of fixed anchors applied in the offshore oil industry. One of the main achievements of these numerical tools is the reduction of the uncertainty related to the bearing capacity prediction of these anchors. Therefore, it is possible to reduce the design safety factors values that have been calibrated based on prediction models with higher uncertainty, without impairing the original level of the structural safety. This paper presents a reliability-based safety factors calibration study for the design of torpedo anchors considering the statistical model uncertainty evaluated using the results from some experimental tests performed by PETROBRAS and their correspondent finite-element based numerical estimates. Both Working Stress Design (WSD) and Load and Resistance Factors Design (LRFD) design methodologies are investigated.