The offshore oil exploitation achieves great complexity, reaching deep and ultra-deep-water depths, employing Floating Production Units. The scenario of random environmental loads would ideally require for the risers’ design thousands of numerical simulations to predict the largest number of representative environmental combinations that may occur during 20-25 years of operation, thus ensuring a detailed assessment of the structural response of risers and mooring lines. However, would require simulations with high computational costs in computer clusters, which can impact both the schedule and the cost of the project. Therefore, to circumvent this difficulty, deterministic analyses are still very present in riser design, as they have low computational cost and present conservatism in their results. To mitigate this conservatism, the objective of this study is the development of a new methodology for the analysis of risers based on the use of an expeditious computational tool, based on RAO theory [1], called SRAO (Structural Response Amplitude Operators). This tool can create the SRAO of a riser automatically to evaluate any effort from any point of its structure to be used in random and fatigue analysis [2] with numerous environmental conditions with very low computational cost. It arises along with the advancement of surrogate models [3], offering also a cost-effective alternative to this scenario. This work presents a comparative study of the structural results of an actual riser obtained by the developed SRAO tool and by Finite Element Method [4], also comparing the computational costs involved. It is pointed that the SRAO can be used for several environmental condition in riser analysis, achieving less than 10% of the CPU cost of a FEA with a typical mesh and can be used to filter the most important environmental conditions to be reevaluated by a FEM. This tool can also be applied in the real-time monitoring of these structures with good quality of results, thus bringing relevant advantages for application in the offshore industry.