Numerical study of the vibrational absorption considering the periodic foundation effect in a small structure

Abstract

The growth of urban areas has led buildings to come closer and closer to road traffic routes, exposing civil buildings to traffic vibrations, causing discomfort for users and damage to structures. Although there are numerical studies on traffic vibrations, effective vibrational isolation techniques are little explored in this research. A promising approach is the use of periodic structures. Although used in several areas of engineering, periodic structures still have limited application in civil engineering, especially to isolate vibrations caused by vehicles rolling on pavement in small buildings. In this context, this research developed three numerical finite element models for a small structure, which represent residential and/or commercial buildings with a number of floors equal to or less than three, in reinforced concrete. The first model involved a periodic block-type structure foundation, while the two comparative models included periodic raft-type foundations and block-type concrete foundations. The objective was to analyze the vibrational absorption of different foundations for forced vibrations arising from road traffic in the 1-50Hz range. In order to compare them and observe how beneficial the use of periodic foundation is, in the context of the study. The methodology used consisted of creating structural models using finite elements, applying boundary conditions to couple the foundation layers and the structure, establishing continuity. The study looked for modal responses, and in the frequency domain, resulting from excitation in the foundation, using the Ansys® software (2023) for all simulations. The results revealed that periodic foundations are capable of reducing amplitude peaks at frequencies above 30 Hz, which is beneficial for attenuating vibrations in this range. With an appropriate design, adjusting the geometric and physical parameters of the materials, it is possible to obtain effective vibrational isolation for structures, minimizing vibrations arising from ground waves in buildings. This suggests that the use of periodic structures would be promising in isolating vibrations caused by traffic in small structures.