Optimizing Mass Concrete Foundations for Low-Frequency Rotary Machines: Role of Rubberized Concrete and Geometric Modifications

Mass concrete foundations are widely used to support low-frequency rotary machines due to their high inertia and stiffness, which help in controlling vibration amplitudes and avoiding resonance. However, conventional mass concrete relies primarily on weight and stiffness, offering limited inherent damping. This study numerically investigates the dynamic performance of mass concrete machine foundations by incorporating material modification through rubberized concrete and geometric optimization through trapezoidal foundation shapes. Four foundation configurations are analyzed using three-dimensional finite element analysis of rectangular conventional concrete, rectangular rubberized concrete (10% coarse aggregate replacement), trapezoidal conventional concrete, and trapezoidal rubberized concrete. Static structural, modal, and steady-state harmonic response analyses are performed to evaluate stresses, deformations, natural frequencies, and vibration amplitudes under machine-induced dynamic loads from a low-frequency centrifugal pump. The results demonstrate that rubberized concrete significantly enhances damping and reduces vibration amplitudes, while trapezoidal geometry improves stiffness distribution and stress transfer to soil. The combined use of rubberized concrete and trapezoidal geometry provides the most effective vibration control, indicating a viable and sustainable alternative for foundations supporting low-frequency rotary machinery.