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• In-situ measurements were made under non-isolated and isolated site conditions. • A special wave barrier was designed for optimum passive isolation model. • The surface wave propagation in the most unfavorable geotechnical conditions. • The vibration isolation performance of open barrier with aerated concrete wall. • Evaluation of vibrations in buildings in terms of velocity level and insertion loss. The aim of this study is to examine the vibration behavior of a special test building close to the high-speed railway line. The surface wave propagation in the most unfavorable geotechnical conditions produced by the moving load source under passively isolated and non-isolated site conditions. For this purpose, special prefabricated panels with low impedance were used to be placed in the trench. Isolation effectiveness of open trench with thin aerated concrete walls is studied on structural response and free-field surface ground vibrations. An important isolation performance of up to 12 dB was obtained only at the half-wavelength depth of excavation. [ABSTRACT FROM AUTHOR]

An artificial bedrock as wave impeding barrier can be used in practical civil engineering applications as isolation measures to protect structures from strong vibrations transmitted through soft ground nearby high-speed railway track. This study focuses on mitigation of the effects of high speed trains inducued vibrations on the strucutres which are located near the track lines by installing wave impeding barriers. Extensive parametric studies on the screening performance of wave impeding barrier have been done for both active and passive isolation cases. [ABSTRACT FROM AUTHOR]

High-speed train (HST) vibrations in the dense residential and industrialized areas founded particularly on soft soil deposits, may lead to discomfort in daily human life, decrease the serviceability life of the structural elements and malfunctioning of the sensitive electronic equipment used in industrial production. In this paper, in-situ measurements were carried out in the free field conditions to examine the effects of ground vibrations caused by HSTs on the surrounding residential lands. Due to both variation in geological and topographical characteristics and railroad track-support properties, the section between "Gebze-Pamukova" has been considered as the target test area of the Istanbul-Ankara HST line in North-Western Turkey. This in-situ experimental study provides comprehensive measurement data that structural engineers and city planners can evaluate in the feasibility phase of the project when planning residential and industrial facilities in new settlements nearby railroads. • Site-specific ground vibrations were measured on Istanbul-Ankara high-speed railway. • In-situ investigations at the grade, embankment and culvert sections were performed. • The subsoil stiffness and stabilization of the route modifies vibration generation. • A resonance case is observed at the train passing on the elevated rail embankment. • Track earthworks affect the transmission of ground vibration to the environment. [ABSTRACT FROM AUTHOR]

The aim of this study is to consider the effects of the variation of shear modulus ratio (G/G0) and damping ratio (ξ) of soil, obtained by a linear iterative method based on the design spectra of seismic codes, the soil environment in terms of uncertainties in shear modulus using Monte Carlo simulations and the foundation damping (ξf) of flexible base for analyses of the Soil-Structure Interaction (SSI) problems. A squat structure with circular shallow foundation resting on a soil layer over a homogeneous half-space is studied by using cone model and considering seismic zone effect on structural response. Firstly, after showing the effects of the correction of G and ξ on impedance functions and the responses of soil-foundation-structure system, a study is carried out to compare these effects to those of the modelling of uncertainties in shear modulus as random variations. Secondly, a comparative analysis on design response spectra and base shear forces was carried out for four seismic codes (Algerian Seismic Rules RPA99-2003, Eurocode 8–2004, International Building Code IBC-2015 and Indian Code IS-1893-2002) considering the three cases of SSI: SSI effects (initial G and ξ), nonlinear SSI (corrected G and ξ) and stochastic SSI (random G with COV = 20%) compared to the fixed base case. Results show that the correction of G and ξ, according to the equivalent nonlinear method in all the cases, leads to a remarkable decrease in peak responses but show a huge amount of reduction in the second study for IBC-2015 and IS-1893-2002 codes compared to the other codes. [ABSTRACT FROM AUTHOR]

The goal of this study is to provide a stochastic method to investigate the effects of the randomness of soil properties due to their natural spatial variability on the response spectra spatial variation at sites with varying conditions. For this purpose, Monte Carlo Simulations are used to include the variability of both incident ground motion and soil parameters in the response spectra by mean of an appropriate coherency loss function and a site-dependent transfer function, respectively. The approach is built on the assumption of vertical propagation of SH type waves in soil strata with uncertain parameters. The response spectra are obtained by numerical integration of the governing equation of a single-degree-of-freedom (SDOF) system under non-stationary site-dependent and spatially varying ground motion accelerations simulated with non-uniform spectral densities and coherency loss functions. Numerical examples showed that randomness of soil properties significantly affects the amplitudes of the response spectra, indicating that as the heterogeneity induced by the randomness of the parameters of the medium increases, the spectral ordinates attenuate. [ABSTRACT FROM AUTHOR]

Earthquakes have destructive influences onto lifeline engineering and especially leading to considerable economic loss to the underground structure. Underground structures are significant unit of lifeline engineering. . Applying horizontal wave barriers is used in civil engineering as an alternative solution to reduce the soil vibrations in the wave propagation region and surrounding of the structures to be protected. In this study, discrete computer model including non-linear soil conditions as well as radiation damping is improved for testing corresponding wave propagation of earthquake vibrations in the soil under 1999 Kocaeli earthquake strong ground motion and mitigation of buried pipeline responses. Extensive parametric investigations by using the developed numerical model for isolation systems have been executed to conceive the influence of different controlling parameters on the screening efficiency. Results indicated that WIB are very promising as a cut off frequency isolators by reduction of * 70% and a promising candidate for future application in the field. [ABSTRACT FROM AUTHOR]

This study evaluates the effect of high-speed train (HST)-induced environmental vibrations using simplified computational models and validates the test results in full-scale field conditions. Experimental investigations and in-situ measurements were performed at the Istanbul-Ankara high-speed railway section to examine the effect of ground vibrations from HSTs on the surrounding residential lands. In this study, ground-borne free-field surface motion at different distances from the railway track was realized using accelerometers. The experimental results of vertical and horizontal ground vibration accelerations induced by HSTs with a velocity of 250 km/h were analyzed. In the first part of the study, a two-dimensional (2D) numerical model based on finite element method (FEM) was used to investigate ground vibrations and validate the experimental results. To minimize artificial reflections and dissipate vibrational energy at the boundaries, the lateral extension of an infinite domain was modeled with viscous absorbing boundaries. A dynamic analysis of the proposed railway-soil coupled model was performed in the time domain under plain-strain conditions using Plaxis 2D, a commercial FEM software. For the verification, the experimental results were compared with those obtained from the numerical analysis. The simplified computational model validated by the test results may help researchers determine further investigation strategies to develop cost-effective mitigation measures for structures with sensitive devices near the railway track and significantly contribute to understanding complex wave propagation problems. In the second part of the study, train-induced environmental ground vibrations were analyzed for different types of soil conditions using a 2D FE model. Computational analyses were performed with four types of soil: soft, medium, dense, and rock, based on the Turkish Earthquake Code. The HST was used as a dynamic source to observe the differences in vibration generation and wave transmission in different types of soil. The HST load on the slab track was simulated to study the effect of operational loads on ground-borne vibrations. Based on the dynamic analysis results, the response of the free-field motion was investigated to obtain the relative acceleration time histories for different points of soil. According to the results, the peak acceleration values of train-induced vibrations at soft, medium, and dense soil sites increased dramatically when compared to the rock site. Vibration measurement data collected from parametric experiments with a simple numerical model for various soil characteristics can be particularly useful when planning residential and industrial facilities at new locations near railroads, to avoid the adverse effects of environmental vibrations caused by HSTs. [ABSTRACT FROM AUTHOR]