TOPCAT Current and Future Developments
Authors: Jhita Parvinder S. , Garland David J. 
Published: October 2008

This paper summarizes the work preformed by Engineering Dynamics, Inc. (EDI) to translate TOPCAT from a research program to an efficient engineering analysis program. The program is now available commercially as part of EDI's SACS suit of programs for the design and analysis of offshore platforms. TOPCAT has been designed to be compatible with existing computer programs and platform analysis systems.

Introduction to TOPCAT

TOPCAT1–3 (Template Offshore Platform Capacity Assessment Tools) is an outgrowth of the ULSLEA (Ultimate Limit State Equilibrium Analysis) program previously developed by the Marine Technology and Management Group at University College Berkeley.

TOPCAT is an analysis program intended for the preliminary structural design and assessment of fixed steel offshore platforms. The program consists of pre-processing features, which allows a user to input the basic geometry and member characteristics in a number of different ways; computational routines for storm, earthquake, and fatigue analysis; post-processing features which allow the user to generate reports and view results in a graphical form. TOPCAT enables the user to quickly develop a simple structural model for one of several standard platform types and then analyze the model for the following conditions:Wind, Wave and Current LoadsEarthquake LoadsFatigue resulting from cyclic wave loading

TOPCAT is oriented towards accessing the load carrying capacity of major structural members such as legs, diagonal bracing, unbraced deck legs, caisson guy-wires and piles. Decks, boat landings and conductor are input as non-structural members which collect load.

The program will accept input for a guyed caisson and three, four, six eight and twelve leg jacket structures. The soil beneath the platform can be specified as having multiple layers of either sand or clay with different strength properties. Grouted joints, braces having significant out-of-straightness or dented members can also be included in any analysis.

In addition to the ultimate capacity analysis, the user may also perform a limited reliability analysis by specifying statistical information on the uncertainties associated with the different strength components. The program will calculate the reliability in terms of a safety index. Assuming that the platform capacity is governed by the capacities of its components as a series system, then the platform will fail when any one of its components fail. Therefore, the overall reliability of the platform will be equal to the lowest component reliability determined for each principal direction.

Current Developments

EDI has converted TOPCAT from its initial spreadsheet format into a Windows Multiple Document Interface (MDI) program that can handle four types of documents: ASCII format text document, TOPCAT graphical document, TOPCAT model document and an associated TOPCAT display document.

The required input data can be entered using a combination of the following four methods:Import a SACS structural modelVia a series of dialog boxes (traditional TOPCAT format)Via command files with input data prepared using an English like command languageUsing the TOPCAT graphical model editor.