NUMERICAL PREDICTION OF GROUND-BORN VIBRATIONS ON A BUILDING PRODUCED BY TRAFFIC

Abstract When a building is constructed close to high-speed traffic infrastructure, the assessment of the level of vibration in those structures is relevant to guarantee safety and comfort. As long as the number of those buildings is continuously raising, is important to have a method to evaluate ground-born vibrations that require the lower computational time possible. The purpose of this study is to develop a new method that allows studying ground-borne vibration, splitting the procedure to evaluate the induced vibrations in the structure in several steps, to reduce drastically the computational time of the whole process. With this aim, several FEM-PML models have been created, to compute the impedance of the foundations, the foundation displacements when a unitary load that simulates the traffic is applied, and also for the reference solution, which consists of the super- structure over the whole soil domain, used to compare the results. In addition to that, FEM models of the building, with the impedance at the bottom of the columns and the computed displacements applied as a base motion, have been used to evaluate the vibration levels on the floors. The analysis of the impedance and the foundations’ displacements have been conducted by taking into count a frequency range from 0.1 to 30 Hz, with a frequency step of 0.5 Hz, while the study on the velocity levels on the building has been conducted on the same frequency interval, but with a frequency step of 0.05 Hz. The unitary load that simulates the traffic has been placed 15 m far from the center of the building. The eigenfrequencies of the building have been evaluated before and after the intro- duction of the impedance at the bottom of the column, to see how the presence of the soil impacts the building itself, but also to check that the peaks in the frequency of the final results describe properly the building behavior. The velocities of the floors have finally been evaluated and compared to the ones ob- tained by running the model that represents the reference solution, to check the relia- bility of the method.