Structural performance of marine circular reinforced concrete piers under axial loading

In this study, an analytical framework was developed for the analysis of the structural behavior of marine circular RC piers under axial compressive loads, accounting for material and geometric nonlinearities. The proposed methodology includes the biaxial stress-strain relationships of concrete and reinforcement within the anisotropic behavior that these materials exhibit under loads. With this type of methodology, it is possible to model critical factors such as concrete cracking, reinforcement yielding, and material interactions. In addition, geometric influences, including slenderness and stability, were analyzed to properly understand pier performance. A parametric study was extended to the influence of the main design parameters, namely, concrete compressive strength, pier height, and reinforcement ratio. Indeed, higher classes of concrete strength provide an important increase in the load-bearing capacity and improvement in structural behavior. The same trends were observed with respect to the variation in pier height, which directly affects the slenderness ratios and stability parameters, indicating geometrical dimensioning optimization in the process of structural design. The reinforcement ratio has a positive effect on the critical stress distribution and enhancement of the critical load capacity. Subsequently, a series of FEA using the DIANA program was performed to verify the analytical framework. As a result, all the FEA results featured by good correspondences against such an analytical prediction are provided in proving the effectiveness of the proposed method with a sufficient degree of precision. This alignment underlines the effectiveness of the analytical approach for understanding the complex behavior of RC piers subjected to axial compression. Keywords: marine structures; offshore structures; circular reinforced concrete piers; axial compression; slenderness; finite element analysis (FEA); load-bearing capacity; stability.