1. Introduction

Analysis of structures will in general involve large and complex numerical models both with respect to the loading and the structure. This typically implies extensive computational efforts. For cases where a large number of load and response calculations are repeatedly performed this becomes particularly cumbersome, such as in the case of Monte Carlo simulation. In the present paper, application of physics-based response surface methods for the purpose of reducing computation time is illustrated. In Section 2, various types of numerical approximations are first discussed in connection with a very simple structure. In Section 3 a complex offshore jacket structure is analyzed by means of response surface techniques for the loading and a physics-based "digital twin" of the structure.
