Analisis perilaku displacement fondasi blok akibat beban vibrasi pada tanah pasir padat

Machine foundations play a crucial role in transmitting static and dynamic loads generated during rotating machinery operation. Uncontrolled dynamic responses of foundations may lead to operational disturbances and degradation of system performance. One of the key geometric parameters influencing this response is the block foundation thickness, which is directly related to the foundation mass and inertia. This study investigates the effect of varying block foundation thickness on the displacement response of machine foundations subjected to harmonic dynamic loads. The analysis was conducted using finite element–based numerical modeling with PLAXIS software. The subgrade was modeled as dense sand using the Hardening Soil Model, while the foundation was represented as an elastic concrete block placed directly on the ground. Harmonic dynamic loads with a frequency of 50 Hz and a phase angle of 0° were applied to simulate generator and turbine vibrations. The results indicate that increasing the foundation block thickness significantly reduces the displacement amplitude, with the response dominated by the vertical displacement component. For generator loading, increasing the block thickness from 0.5 m to 1.5 m reduces the resultant displacement by approximately 46%, while turbine loading results in a reduction of approximately 26% over the same thickness range. The most effective reduction occurs for block thicknesses between 1.0 m and 1.5 m, beyond which additional increases in thickness provide only marginal displacement reduction, indicating a diminishing return effect. Based on these findings, a block foundation thickness of approximately 1.5 m can be indicatively recommended as an optimal thickness to mitigate displacement response due to vibration loads under the analyzed soil and loading conditions.