We, humans, are today increasingly in search of land and marine energy resources due to the growing demand for energy resulting from scientific and technological advances. This huge demand, especially for fossil fuels, requires extensive extraction operations. The fact that a significant percentage of such resources are marine fossil fuel resources has emphasized the necessity for the development of marine or offshore structures. In marine structural engineering, the key factor to consider is the force applied to structures by waves. In the present study, we achieved interesting results by investigating the level of wave run-up and force applied to the structure's legs, the effect of their distance and geometric shape on the two mentioned parameters and their layout modifications and the related effect on the run-up and force, and also the effect of the longitudinal leg distance value in the case of circular, oval, and hexagonal sections through a comparison using FLOW-3D. We found that the force and, consequently, the run-up are reduced in the components of these legs as the distance between the legs is increased, especially in the case of circilar section.