Ground-borne Vibration In Buildings Research Articles

An experimental/numerical hybrid methodology for the prediction of railway-induced ground-borne vibration on buildings to be constructed close to existing railway infrastructures: Numerical validation and parametric study

A novel experimental/numerical hybrid methodology for the assessment of railway-induced ground-borne vibration in buildings based on experimental measurements in the soil surface is proposed in this paper. This methodology has been specifically designed for the prediction of railway-induced vibration in buildings to be constructed close to an operative railway infrastructure, although it can be applied for other types of vibration sources. The model of the incident wave field induced by the railway infrastructure consists of a set of virtual forces applied in the soil, which would be obtained from vibration experimental measurements in the surface of the ground where the building will be constructed. These virtual forces can be subsequently applied to a model of the building-soil system to obtain a prediction of the vibration levels that will be induced by the existing railway infrastructure to the studied building. In the present work, this methodology is theoretically defined and it is numerically validated for two-dimensional and two-and-a-half-dimensional cases. To numerically test the methodology, the measured ground surface responses are replaced by simulated ones obtained in a set of points called collocation points. In this context, a parametric study has been developed with the aim of finding out a robust criterion for the application of the present methodology with respect to the amount and location of the collocation points (representing vibration sensors) and virtual forces. It is found that the distance between virtual sources should be smaller than the S-wave wavelength of the upper soil layer corresponding to the highest frequency of the frequency range of interest to ensure the reliability of the methodology. Moreover, the proposed method is found to be insignificantly affected by the building-tunnel dynamic coupling for building-tunnel distances above 20 m. The proposed hybrid model would simplify the usual numerical prediction approach commonly adopted for dealing in detail with these problems, since a model of the railway infrastructure is no longer required. Moreover, it would reduce the uncertainty of the prediction due to the use of experimental measurements of the particular site to be studied. In addition, it would provide a higher accuracy and flexibility than empirical models based on experimental transmissibility functions between the soil surface and the building.

Experimental study of isolation in the backfill zone of the foundation pit (IBF) method to reduce ground-borne vibration in buildings

Structural vibration caused by road traffic disturb the comfort of people in nearby buildings and induce various public health hazards Isolation trenches can reduce vibration but are often not practical in large cities. This paper proposes the isolation in the backfill zone of the foundation pit (IBF) method to reduce the building vibration using the existing construction backfill zone. A new isolation product, which has high axial stiffness and low shear stiffness, was developed. The IBF method, which employed the product, can restrain the building foundation and provide good vibration isolation. A method for designing the high axial stiffness and low shear stiffness (HALS) vibration isolation product was also proposed. Two four-story test buildings were constructed and full-scale on-site tests were conducted. The vibration transmitted through the basement sidewalls was measured and the effectiveness of the IBF method was investigated. It was observed that the IBF method can reduce 31–53% of the vibration transmitted to the building.

Efficient Three-Dimensional Building-Soil Model for the Prediction of Ground-Borne Vibrations in Buildings

AbstractThis paper proposes a new efficient model for the prediction of low-amplitude ground-borne vibrations in buildings. The model takes into account the three-dimensional nature of the building...

A numerical analysis of the influence of tram characteristics and rail profile on railway traffic ground-borne noise and vibration in the Brussels Region

Nowadays, damage potentially caused by passing train in dense cities is of increasing concern and restricts improvement to the interconnection of various public transport offers. Although experimental studies are common to quantify the effects of noise and vibration on buildings and on people, their reach is limited since the causes of vibrations can rarely be deduced from data records. This paper presents the numerical calculations that allow evaluating the main contributions of railway-induced ground vibrations in the vicinity of buildings. The reference case is the Brussels Region and, more particularly, the T2000 tram circulating in Brussels city. Based on a pertinent selection of the vibration assessment indicators and a numerical prediction approach, various results are presented and show that the free-field analysis is often improperly used in this kind of analysis as the interaction of soil and structure is required. Calculated high ground vibrations stem from singular rail surface defects. The use of resilient wheels is recommended in order to reduce the ground-borne noise and vibration to permissible values.

A non-parametric probabilistic model for ground-borne vibrations in buildings

This paper studies the prediction accuracy of models for ground-borne vibrations in buildings based on a three-dimensional coupled FE–BE formulation in the frequency range relevant for traffic induced vibrations. In structural dynamics, the prediction accuracy at relatively high frequencies is known to be problematic since the sensitivity of the predicted response to modelling errors and parameter uncertainties increases with the frequency. To estimate the prediction accuracy, this paper incorporates the parameter uncertainties and the modelling errors into the analysis using the non-parametric probabilistic approach, introduced by Soize. The methodology is applied to a case history. The results of a prediction model for the transmission of vibrations from a shallow cut-and-cover tunnel to a six storey reinforced concrete frame structure in Paris are considered and compared with in situ measurements. The results demonstrate that a single dispersion parameter allows fitting the data. The sensitivity of the response to uncertainties is shown to increase as vibrations propagate inside the building.

Building Response due to Subway Train Traffic

There are several existing methods for determining groundborne vibrations in buildings due to subway train traffic that are essentially based on empirically derived relationships. These methods are not able to handle buildings with unique foundations in unusual geological conditions with reasonable accuracy. The case in this study, which comprises a four-story podium block enclosing twin double-box tunnels within the confines of its ribbed-wall foundations, presents such a situation. In contrast, this paper presents a more accurate approach, which employs the finite-element method and is capable of modeling the complicated subway-soil-structure interaction problem. Furthermore, an analytical model is incorporated to provide the train-loading input. For verification, in situ measurements were taken, both at the tracks and within the building. The analytical results obtained showed reasonable conformity with the measurements taken.

Groundborne vibrations due to trains in tunnels

AbstractAn analytical procedure is presented for determining groundborne vibrations in buildings due to subway trains. The procedure involves a finite element idealization of the subway‐soil‐structure interaction problem, using an analytical model for the train loading spectrum at the tunnel invert. Both direct fixation and floating slab track support systems are considered. The train model is verified using the measurements of rail velocities. The proposed procedure is applied to the case of a four‐storey podium block enclosing twin double‐box subways within the confines of its ribbed wall foundations. The severity of velocity response levels of the building, in relation to vibration standards, is also considered.

Ground-borne vibrations in buildings near subways

A simple method for predicting excitation levels due to ground-borne vibrations in buildings near subways is presented. The method is based on approximate impedance formulae for the tunnel and the structure and simple energy considerations. Comparisons between calculations and measurements on scale models show that, despite the simplifying assumptions made, the predictions are acceptable for design purposes.

Transmission of Ground-Borne Vibration in Buildings

A project has been carried out at the Danish Acoustical Institute in which the connection between the vibration level in the ground outside a building and the vibration level on the floors of the building was investigated. The project is a continuation of an earlier investigation into the propagation of vibration from rail traffic. Based upon measurement results from six buildings, a set of typical transfer functions between a point in the ground and points inside buildings were determined