Browsing by Subject "dynamika budowli"

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Access status: Open Access ,
Machine-learning methods for assessing dynamic resistance of existing bridge structures subjected to mining tremors
(Wydawnictwa AGH, 2018) Rusek, Janusz
This paper demonstrates the results of research studies aimed at creating a model that allows to determine the resistance of existing bridge structures to the impact of mining tremors. A database (created by the author of this article) of the dynamic resistance of reinforced concrete bridge structures subjected to seismic excitations commonly occurring in the Legnica-Głogów Copper District (LGOM) formed the basis for the analysis. The dynamic resistance of each structure contained in the database was expressed as the limit values of the acceleration of ground vibrations that may be carried by a given structure without compromising its safety. The study was carried out using the Support Vector Machine (SVM) method in a Support Vector Regression (SVR) approach as well as an Artificial Neural Network (ANN). The models were compared in terms of the quality of the predictions and generalization of the acquired knowledge. This allows to select the most-effective method in evaluating the dynamic resistance of existing bridge structures.
Access status: Open Access ,
Procedure of building and analysis of the information database of the resistance of existing bridge structures to mining tremors
(Wydawnictwa AGH, 2017) Rusek, Janusz
Mining tremors are one of the manifestations of negative impacts of the mining industry on the environment. In order to protect building structures against the damaging effects of ground vibrations, it is required that their dynamic resistance be determined. This problem is of particular importance for the existing bridge structures that were not designed for the potential occurrence of mining tremors. This paper presents the assumptions of and a method for acquiring data on the dynamic resistance of existing bridge structures located in mining areas as a result of numerical calculations using the Finite Element Method (FEM). Object resistance was described by the limit values of the acceleration of ground vibrations in the vertical and horizontal planes that can be carried by the existing structure without compromising safety. Taking into account the geometrical and material diversity, 3,000 numerical models of reinforced concrete overpasses were created. Then, for each object, numerical calculations using the FEM were performed, which resulted in the determination of permissible values of the acceleration of ground vibrations defi ning their dynamic resistance. The created database was subjected to a preliminary analysis in order to detect linear relationships binding the data that describe the geometry and material properties of individual structures with their dynamic resistance to the impact of mining tremors. As a result of these studies, variables were selected that formed the basis for creating a multiple linear regression model (MLR). Analysis of the obtained results allowed us to assess the possibilities of using linear models to determine the dynamic resistance of bridge structures subjected to mining tremors.