SACS Analysis and Structural Engineering
Used by CUEL Structural Engineers, SACS is a design tool and technique that supports the structural analysis, design, fabrication and installation of offshore structures, including oil and gas production platforms and well-head platforms. It is a design tool which is widely used throughout the offshore oil and gas industry.
SACS is primarily used by engineers to model structures and analyze their behavior under a variety of operational conditions. SACS is used to model all primary structural components including jackets, pile foundations and topsides (decks). Jacket structures support the topsides which contain the processing facilities able to process, handle and transport the hydrocarbons produced, which can be either oil or gas, or both.
SACS has the ability to dynamically model and subsequently perform designs, and this allows CUEL Structural Group to perform advanced analysis and comply with offshore design criteria and other requirements from codes, standards and specifications. More importantly, it allows CUEL Structural Group to optimize jacket, pile and topsides structural designs, to ensure cost-effective results consistent with technical integrity and assurance. What this means is, CUEL can develop designs which comply with all design requirements, codes and standards but still have the design optimized to ensure structural member sizes are fit for purpose but not oversized, which by definition then adds weight and cost to the structure.
SACS computer-aided designs allow engineers to model structures in a fraction of the time if the calculations and analyses were to be done by hand calculations. If we modeled structures using hand calculations then we would be in a long process to ensure all design requirements were met. The process could take weeks or months for complex structures. Using SACS enables structures to be analyzed and designed in a matter of days. It also ensures that the designs are optimized and the contingencies minimized for unknown design factors.
SACS provides the offshore structural design engineers with comprehensive analysis and design capabilities. These improve operational safety, minimize risk and ensure compliance for a broad range of structures. SACS enables structures to be designed for a range of environmental loadings including wind, current, wave and seismic load cases. SACS can also handle and incorporate analysis for ship impact and structural collapse.
In fact, SACS can model a range of configurations including jackets, foundations and topsides as well as perform detailed fatigue life calculations. However, CUEL use SACS in a more limited capacity consistent with the company’s focus on well-head platforms. SACS supports ongoing efforts to ensure that these designs and structures are optimized at every step of the design process.
SACS relies on a set of input data to accurately model the structures. The accuracy and validity of the input data is crucially important in getting the right outputs from the program. This then allows materials to be specified and designs to be progressed to the next stage, producing detailed design drawings. Typical inputs for the SACS program include:
• Structural Geometry
• Material Properties
• Boundary Conditions
• Seastate and Load Conditions
• Structural Conditions
Outputs from the SACS analyses include:
• Stresses and Forces
• Displacements
• Fatigue Damage & Fatigue Life
• Dynamic Response
• Reserve Strength
• Structural Simulation
SACS is an important design tool and technique which relies on people with the right skills and abilities to input data, define operating envelopes and analyze outputs. It is a skill which requires many years of experience and exposure to different design criteria and conditions to allow engineers to become SACS experts. The ability to interpret and analyze results is an important consideration for the Engineering and Design Department, as the results from this analysis impact downstream across the EPIC value chain.