For geotechnical engineering and design of foundation elements of structures is important to properly determine the stress-deformation state of the subsoil. The calculation is most often done using the finite element method and the computational models. This article includes the parametric study for the selected type of concrete foundation structures. The article focuses attention to the calculation of the deformation of the slab with respect to the influences of individual input parameters (e.g. stiffness of concrete and subsoil, boundary condition, size of elements). Calculations are performed for two concrete types and three soil variants.
Problematic of soil -structure -interaction is subject of research for many years, however satisfactory accuracy of numerical models has not been achieved yet.Therefore, it is necessary to examine this phenomenon.For this purpose, special testing equipment was built at Faculty of Civil Engineering in Ostrava and series of experimental tests were performed.One of the tested slabs was chosen and its numerical model was created in computational program Ansys 18.0.Numerical model consists of two parts -slab and soil, connected with a contact element.From the test and the model data, maximal deformations and deformations trough the cross section of the slab were compared.This paper examines whether the Hooke's law is valid and can be used to express the test behavior and locate elastic effect area allowing linear modelling which can be useful for lowering computational time.
Multi-parameter fracture mechanics is nowadays quite extensively applied when cracked structures/specimens are investigated. The reason was that it has been shown that it can be helpful and bring results that are more accurate when for describing of fracture processes a larger region around the crack tip is used. This can be typical for material like concrete or other materials with quasi-brittle behaviour. Various relative crack length configurations were chosen in order to investigate the importance of the higher-order terms of the Williams expansion (WE) on the crack-tip stress field distribution in Wedge splitting test specimen. The higher-order terms were calculated by means of the over-deterministic method from displacements of nodes around the crack tip obtained by a finite element analysis in different radial distances from the crack tip. The effect of the constraint level (second member of WE) was investigated. Although the third and higher terms of the Williams series are very often neglected, their influence on the opening stress values was investigated and discussed.
. The submitted contribution provides background information on the principles accepted in the CEN Technical Specification (TS). The application of the verification methods provided in the TS is clarified by an assessment of a reinforced concrete precast panel. The panel provides insufficient resistance in comparison to that required by Eurocodes for design of new structures. The critical comparison of the reliability levels indicated by Eurocodes, the assessment value method, and fully probabilistic approach demonstrates the benefits gained by applying the principles of the TS. While the partial factors recommended in Eurocodes leads to a negative result the assessment value method and the probabilistic method indicate sufficient structural reliability.
Small wind generators are successfully applied for outdoor lighting on highways, parks, seaside boulevards.We developed technologies that gives an opportunity to manufacture wind rotor, the main element of this type of generators, using basalt fiber composite, and to manufacture generator itself.Based on the research data we manufactured 200 w capacity wind generator equipped with basalt fiber composite blades.
The aim of this paper is to present the numerical model of the fracture response of the test specimens with a steel inclusion in the shape of the prisms which length is equal to the specimen’s width. Specially designed fine-grained cement-based matrix specimens of the nominal dimension 40 × 40 × 160mm with inclusion of 8× 8× 40mm and central edge notch serves to determine of the influence of the interfacial transition zone on the effective mechanical fracture parameters of composite. The numerical models of three-point bending test of these specimens are created in ATENA software.
. This article presents the numerical modeling of interaction between a reinforced concrete slab and subsoil using ABAQUS. Subsoil was simulated as both homogeneous half-space and inhomogeneous half-space. Reinforcement bars in the concrete slab were accurately modelled allowing capturing a precise deformation profile of the slab in interaction with subsoil. Input data for numerical analysis were adopted from a published work. Results of the study were verified on the basis of comparison with those of the previous study.
Fatigue cracks are found during the regular structural inspections.To precisely describe/suggest propagation of fatigue cracks throughout structure and it's designed service life, the knowledge of geometry functions describing the stress situation in front of the crack tip for relative crack lengths are important.The cracks usually propagate/initiated from the edge or the surface of the structural element, where the maximum value of applied load is achieved.The theoretical model of fatigue crack propagation is based on linear fracture mechanics (Paris law).Steel structural elements are subjected to various bending load (three-, four-point bending and pure bending etc.).The geometry functions for the edge cracks are calculated for various span according to real steel bridge elements and appropriate polynomial functions independent on the distance are proposed for three-and four-point bending load.
This article focuses on masonry arch railway bridges. The main topic is the algorithm, which was developed for the purpose of a non-linear arch bridge analysis. The sensitivity analysis of the input parameters of the calculation was carried out. Subsequently, the study was carried out for the comparison of four calculation methods. For this comparison, a set of arch bridges were chosen. Two methods used commercial software, and the other two methods were developed. One of the developed algorithms uses a simple linear calculation. The second developed algorithm uses an iterative approach to handle material and geometrical non-linearity. The first commercial software method uses 2D non-linear models, the second method is a limit collapse analysis using the software LimitState:RING. These three methods were developed to handle the SLS (serviceability limit state) criteria, and their results were compared to the result of LCC at the ULS (ultimate LS) using LimitState:RING.
The paper focuses on brownfields of agricultural facilities in three locations, i.e. in the center of a small village, on the outskirts of the village and in the countryside.Historical sites with cultural and social value were selected for their location, context and their nature or the existence of listed buildings.This created the opportunity to present three model situations of approaches to site solutions.The issues were gradually presented to Master's degree students in Architecture and Civil Engineering at the Faculty of Civil Engineering of VŠB-TU in Ostrava, to allow each of them to create an opinion over the course of the semester on the possibility and level of utilization of abandoned agricultural sites.The results of their work show their thinking on the direction and re-use of the brownfields, primarily influenced by their location, but also by other aspects that had a significant impact on the resulting design concept.
The paper is focused on the technique of linear transformation between correlated and uncorrelated Gaussian random vectors, which is more or less commonly used in the reliability analysis of structures. These linear transformations are frequently needed to transform uncorrelated random vectors into correlated vectors with a prescribed covariance matrix (coloring transformation), and also to perform an inverse (whitening) transformation, i.e. to decorrelate a random vector with a non-identity covariance matrix. Two well-known linear transformation techniques, namely Cholesky decomposition and eigendecomposition (also known as principal component analysis, or the orthogonal transformation of a covariance matrix), are shown to be special cases of the generalized linear transformation presented in the paper. The proposed generalized linear transformation is able to rotate the transformation randomly, which may be desired in order to remove unwanted directional bias. The conclusions presented herein may be useful for structural reliability analysis with correlated random variables or random fields.
This paper focuses on the issue of accessibility and the quality of public space, particularly its barrier -free use and relation to current Czech legislation.The legislative framework should help reshape theoretical knowledge and contemplations of this issue into live practice, which is met with varying success.Important factors in this field include the continuity of the legislative environment and specifics for the given region (primarily in the border regions where there is a collision of the "domestic" and "foreign" legal environments).
In this article authors present results of initial laboratory tests and further numerical analyses using finite element method (FEM) and back -calculation method.Laboratory tests are based on trial loadings of granular material in different moisture conditions.Numerical analyses were obtained in FEM software using Coulomb -Mohr model of tested material.Presented results are the part of wider research program in which the main aim is to evaluate the influence of variable moisture content of granular materials used in road pavement structures on their fatigue life and in Life Cycle Assessment (LCA).
The study presents a comparative analysis of displacements and reduced stresses that occur in the selected node of a truss made of cold-rolled sections.Computations were based on the finite element method using the Autodesk ROBOT Structural Analysis and ANSYS Academic Research Mechanical software.Analysis of the status of the selected node was performed for permanent and variable loads.
. The article deals with the calculation of corrosion losses of weathering steels with dose-response functions. The environmental parameters of atmospheric corrosion incoming the dose-response functions are analysed by statistic and probabilistic methods. Between main environmental parameters belong temperature T, concentration of sulphur dioxide, relative air humidity RH, and deposition of chloride. Long-term measurements of environmental characteristics at atmospheric test sites were used for the analysis. All the environmental parameters incoming the dose-response functions are considered random variables represented by corresponding histogram. Using the probabilistic analysis it is possible to predict the expected range of corrosion rates and to analyse the impact of particular environmental characteristic on corrosion process.
Archaeological excavation at the site Musov -Neurissen conducted between 1993 and 1994 revealed a well belonging to the building with the apse.Both archaeological features were part of the Roman military camp from the Augustan era.The well remained unfinished,however its dimensions (10 x 10 Roman feet (2.96 x 2.96 m) and expected depth of up to approximately 16 m) suggest that this location was chosen intentionally for a realisation of a demanding construction project.
The article deals with the flow over a roughwalled circular cylinder in the critical area at high Re numbers.The subject of the paper is a comparison of the standard calculation of the aerodynamic drag coefficient with numerical modeling.Numerical tasks are solved by the simplified geometry of the smooth cylinder, where the influence of the rough surface is given by the equivalent aerodynamic roughness, and also by the model with the real geometry of the rough casing of the cylinder.
This paper is focused on the static analysis of membrane structures, which are typical for their ability to transfer only tensile forces.Membrane structures are becoming more popular owing to their lower initial cost and potential for use in structures with higher aesthetic claims.However, the designs of membrane face some challenges related to the specific properties of these support systems.This paper aims to analyse the current possibilities for using membrane structures and to evaluate these structures in terms of materials and design details and using numerical methods.
This paper illustrates the use of MIDAS GTS NX to investigate the tunnel's simulation in order to highlight the effect of static and dynamic load on the behaviour of tunnel to compare this response expressed in terms of displacement and stresses acting on the tunnel and ground.Main tunnel is located in the ground having uniform property throughout its extent, connecting gallery is located perpendicular to the main tunnel, the shotcrete and rock bolts for each tunnel will be installed.
