A new falling weight test method based on the direct impact on the rail was studied and a backcalculation model was developed to estimate the moduli of the railway substructure layers. The model is three-dimensional, dynamic, and considers the superstructures. After the preliminary studies on the impact system and measurement setup on a test track, a case study was performed on a railway station track. The data were recorded using a series of linear variable differential transformers, geophones, and accelerometers during the proposed falling weight test on the rail. To establish the soil profile and better understanding of the site, geotechnical and geophysical investigation of the soil was done using in situ and conventional laboratory tests. The studies show that the rail falling weight test is feasible and leads to reasonable results. Verification of the backcalculation model with the ABAQUS finite element simulation and comparison of the backcalculated moduli with the results of site investigations show that the function of the backcalculation model is satisfactory.
Analysis and design of structures subjected to arbitrary dynamic loadings especially earthquakes have been studied during past decades. In practice, the effects of soil-structure interaction on the dynamic response of structures are usually neglected. In this study, the effect of soil-structure interaction on the dynamic response of structures has been examined. The substructure method using dynamic stiffness of soil is used to analyze soil-structure system. A coupled model based on finite element method and scaled boundary finite element method is applied. Finite element method is used to analyze the structure, and scaled boundary finite element method is applied in the analysis of unbounded soil region. Due to analytical solution in the radial direction, the radiation condition is satisfied exactly. The material behavior of soil and structure is assumed to be linear. The soil region is considered as a homogeneous half-space. The analysis is performed in time domain. A computer program is prepared to analyze the soil-structure system. Comparing the results with those in literature shows the exactness and competency of the proposed method.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.