Formation of stress-strain state in the founda-tions of grain drying complexes when chang-ing soil parameters

2020 ◽  
pp. 55-63
Author(s):  
Vasyl Pidlutskyi ◽  
Oleksandr Lytvyn
Keyword(s):  
Pile Foundation ◽  
Strain State ◽  
Pile Foundations ◽  
Soil Parameters ◽  
Bending Moments ◽  
Stress Strain ◽  
Field Methods ◽  
Foundation Slab ◽  
Stress Strain State ◽  
Grain Drying

The work of the pile foundation of the grain drying complex when changing the parameters of soils determined by laboratory and field methods has been studied. Two variants of calculations with the help of numerical modeling by the finite element method were carried out: 1) using the characteristics of soils, which were determined by laboratory methods; 2) using the characteristics of soils, which are determined by field methods. The stress-strain state of the foundation structures of the grain drying complex is analyzed in the work, namely: redistribution of forces in the piles, subsidence of the foundation structures, bending moments and the area of working reinforcement in the foundation slab. The paper emphasizes the use of pile foundations for grain drying complexes due to the emergence of many negative factors in the installation of slab foundations. The main ones are: low soil indicators in the upper zone of the soil massif; construction of several silos next to each other, which determines their interaction; uneven loading - unloading of silos; the choice of calculation method, which correctly describes the parameters of the soil and the stages of loading and unloading of silos. The paper also presents problematic issues in the design of pile foundations for grain dryers. The results of the study of the formation of the stress-strain state of the foundation structures at different soil parameters are presented. The study was conducted in clay soils of solid and semi-solid consistency. The pile foundation is based on hard sandy loams and soft-plastic loams. The paper shows that with increasing soil parameters of the base decreases the subsidence of the foundation slab. The redistribution of forces between the piles has a similar character, but due to the increased rigidity of the base, the foundation plate transfers the load to the base, so almost all piles are unloaded within 5… 10%. At the same time bending moments in the base plate are reduced that demands reduction of reinforcement by working armature. This allows you to design reliable and economical solutions for pile foundations of grain dryers.  

scholarly journals REGULARITIES OF THE LINING STRESS-STRAIN STATE DURING OF THE PYLON METRO STATION CONSTRUCTION

2021 ◽  
pp. 19-27
Author(s):  
D. O. BANNIKOV ◽  
V. P. KUPRII ◽  
D. YU. VOTCHENKO
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Finite Elements ◽  
Strain State ◽  
Finite Element Models ◽  
Bending Moments ◽  
Stress Strain ◽  
Normal Forces ◽  
Stress Strain State ◽  
Station Structure

Purpose. Perform numerical analysis of the station structure. Take into account in the process of mathematical modeling the process of construction of station tunnels of a three-vaulted station. Obtain the regularities of the stress-strain state of the linings, which is influenced by the processes of soil excavation and lining construction. Methodology. To achieve this goal, a series of numerical calculations of models of the deep contour interval metro pylon station was performed. Three finite-element models have been developed, which reflect the stages of construction of a three-vaulted pylon station. Numerical analysis was performed on the basis of the finite element method, implemented in the calculation complex Lira for Windows. Modeling of the stress-strain state of the station tunnel linings and the soil massif was performed using rectangular, universal quadrangular and triangular finite elements, which take into account the special properties of the soil massif. Station tunnel linings are modeled by means of rod finite elements. Findings. Isofields of the stress-strain state in finite-element models reflecting the stages of construction are obtained. The vertical displacements and horizontal stresses that are characteristic of a three-vaulted pylon station are analyzed. The analysis of horizontal stresses proved that at the stage of opening of the middle tunnel the scheme of pylon operation is rather disadvantageous. The analysis of bending moments and normal forces was also carried out and the asymmetry of their distribution was noted. Originality. Based on the obtained patterns of distribution of stress-strain state and force factors, it is proved that numerical analysis of the station structure during construction is necessary to take measures to prevent or reduce deformation of frames that are in unfavorable conditions. Practical value. In the course of research, the regularities of changes in stresses, displacements, bending moments and normal forces in the models of the pylon station, which reflect the sequence of its construction, were obtained.

scholarly journals Modeling of a piled foundation in a Femap with NX Nastran

2020 ◽  
Vol 16 (4) ◽  
pp. 250-260
Author(s):  
Elvira R. Kuzhakhmetova
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Pile Foundation ◽  
Strain State ◽  
Calculation Model ◽  
The Finite Element Method ◽  
Stress Strain ◽  
Foundation Soil ◽  
Stress Strain State ◽  
Building Foundation

Relevance. The underground part of the building (foundation and soil) has a significant impact on its stress-strain state and behavior under the influence of operational loads. Therefore, the existing regulatory and technical documentation regulates the design of buildings (structures), taking into account the joint work of their aboveground and underground parts. In practice, such accounting becomes possible on the basis of a comprehensive engineering analysis of the building as a large mechanical system building - foundation - soil, which today can be carried out using the finite element method. In the case of pile foundations, the correctness of the result depends largely on the reasonable choice of the design model of the pile-soil subsystem. The article analyzes three design models of piles operating in an array of soil foundation. The first model is discrete. In it, the pile is modeled by bars and is based on elastic supports (Spring) with generalized stiffnesses. Second model - spatial, in which the pile and soil are typed in by volumetric elements (Solid). Third model - spatial-bar or combined, in which the bar pile is embedded in the mesh of the soil mass using a rigid substructure formed by bars of high rigidity. The aim of the work - to determine a rational calculation model of the pile - soil subsystem, which allows, on the one hand, to reduce the general order of the system of resolving equations, and, on the other hand, to maintain the accuracy of the assessment of the stress-strain state of the calculation model of pile - soil and the building as a whole. Materials and methods. The numerical results of the analysis of the pile foundation statics using the three pile - soil calculation models were performed in the CAE software package - the Femap with NX Nastran class, which implements the finite element method. Results. Comparative-numerical analysis of the stress-strain state of the pile foundation - soil subsystem made it possible to determine the advantages, disadvantages, and also the areas of rational use of bar, spatial combined calculation models. In the next articles, it is planned to consider the calculation of piles for vertical loads, as well as a comparative analysis of numerical results with experimental data (in the labo-ratory or in field conditions) for horizontal and vertical effects.

scholarly journals NUMERICAL DESIGN OF FRAME BUILDINGS TAKING INTO ACCOUNT THE GENERALIZED STIFFNESS AND LOAD OF SOIL AND FOUNDATION

2019 ◽  
pp. 34-46 ◽  
Author(s):  
E. Kuzhahmetova
Keyword(s):  
Pile Foundation ◽  
Strain State ◽  
Soil Mass ◽  
Reference Points ◽  
Industrial Building ◽  
Stress Strain ◽  
Building Model ◽  
Stiffness Coefficients ◽  
Stress Strain State ◽  
Definition Of

The article is devoted to the improvement of methods for calculating buildings as large finite element systems and implements approaches that provide a definition of the overall picture of the stress - strain state of a designed building (structure) in parts, including its structural units and a pile foundation. The article contains a description of the methodology, the essence of which is to bring the stiffness of the pile foundation in the form of single piles (for example, under the columns of a frame of a public, residential or industrial building) and the adjacent soil mass, to the supporting points of interaction of the piles with the building. Generalized stiffness coefficients of the pile, obtained taking into account the soil with different deformation characteristics, are entered into the general matrix of the building for the subsequent determination of its stress - strain state and stability. At the final stage of moving the reference points of the building, it is possible to calculate the characteristics of the stress - strain state of the pile in the ground. In this article (part 1), the generalized stiffness coefficients of the pile are obtained taking into account the types of soil (sand and clay) with physical and mechanical characteristics selected from regulatory documents. The calculations are performed using the FEMAP with NX NASTRAN software package. The material on the structuring of the building model is supposed to be published in the subsequent parts of this article

scholarly journals JUSTIFICATION OF THE STRESS-STRAIN STATE OF THE PILE FOUNDATION USING SOFTWARE COMPLEXES

2021 ◽  
pp. 13-18
Author(s):  
O. I. DUBINCHYK ◽  
L. O. NEDUZHA
Keyword(s):  
Numerical Analysis ◽  
Pile Foundation ◽  
Strain State ◽  
Operating Conditions ◽  
Design Solution ◽  
Bridge Structure ◽  
Stress Strain ◽  
Stress Strain State ◽  
Software Packages ◽  
Pile Cap

Purpose. Bridge supports with a high pile caps require more attention when calculating their strength due to the difficult operating conditions of the piles. The purpose of the scientific article is to substantiate the stress-strain state of the pile foundation of the bridge structure using software computing systems SCAD and LIRA-CAD. Methodology. An analysis of software used to automate the design of foundations was conducted. The main parameters of SCAD and LIRA-CAD software packages are yielded. With their help, finite-element models of the pile foundation of the bridge support with a high pile cap were built. The developed models maximally reflect the properties of the soil base and foundation, its pile cap and piles, geometric characteristics and the influence of the finite elements meshing is considered. Calculations were performed in SCAD and LIRA-CAD software packages with monitoring of the calculation process. Findings. During the numerical analysis of the pile foundation of the bridge structure with a high pile cap, vertical displacements, force factors (normal forces and bending moments) in the piles and stresses in the body of the support and piles were determined. Based on these results, an analysis was performed, which is combined with a comparison of the obtained results. Implementation of SCAD and LIRA-CAD software allows to significantly reduce design time, to reduce project costs, to improve the quality and efficiency of investments. Originality. A comparison of the stress-strain state obtained during the numerical analysis of SCAD and LIRA-CAD software, which proved the difference in the approach to modeling in these complexes, was conducted. Practical value. The results of substantiation of the stress-strain state of the pile foundation with the use of software complexes made it possible to verify the design solution of all elements of the foundation of the bridge structure with a high pile cap.

scholarly journals Generation of stress-strain state in combined strip pile foundation beds through pressing of soil

2017 ◽  
Vol 106 ◽  
pp. 02011 ◽  
Author(s):  
Maxim Stepanov ◽  
Roman Melnikov ◽  
Juriy Zazulya ◽  
Oleg Ashihmin
Keyword(s):  
Pile Foundation ◽  
Strain State ◽  
Stress Strain ◽  
Stress Strain State

scholarly journals Elaboration of testing technique of flat slabs on punching shear strength using finite element modeling

2018 ◽  
Vol 196 ◽  
pp. 02048
Author(s):  
Valery Filatov ◽  
Zulfat Galyautdinov ◽  
Alexander Suvorov
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Cross Section ◽  
Strain State ◽  
Concrete Slabs ◽  
Finite Element Models ◽  
Bending Moments ◽  
Stress Strain ◽  
Stress Strain State ◽  
Reinforced Concrete Slabs

The results of researches on finite-element models of stress-strain state of flat reinforced concrete slabs of beamless frame under punching by columns of square and rectangular cross-section are presented. The purpose of the study was to develop a technique for testing samples plates for punching in the presence of bending moments in a column. The results of the study of deflections of reinforced concrete slabs, the distribution of bending moments in the punching zone of the plate under various loading schemes are presented. Variable parameter was the ratio of the sides of the column cross-section. Comparative analysis of studies results on finite element models has made it possible to choose the optimal variant of applying the load to the test samples, depending on the aspect ratio of rectangular section of column. Results of the conducted research will allow simulating the stress-strain state in the punching zone of natural reinforced concrete slabs of monolithic beamless frame during the test of samples.

scholarly journals Role of transverse joints in regulation of the reinforced concrete face stress-strain state

Vestnik MGSU ◽  
2018 ◽  
pp. 1533-1545
Author(s):  
Aleksei A. Podvysotckii ◽  
Mikhail P. Sainov ◽  
Vladislav B. Soroka ◽  
Roman V. Lukichev
Keyword(s):  
Numerical Modeling ◽  
Reinforced Concrete ◽  
Strain State ◽  
Tensile Force ◽  
Bending Moments ◽  
Stress Strain ◽  
Tensile Stresses ◽  
Stress Strain State ◽  
Transverse Joint ◽  
The Face

Introduction. Deals with the results of studying effectiveness of arranging transverse joints in the face as the means of regulation of its stress-strain state. At present reinforced concrete faces are constructed without being cut height-wise and transverse joints may be arranged only at the end of the dam construction stages. This is validated by the fact that experience in construction of flexible (discontinuous) faces has not demonstrated the required level of safety of this structural design. However, in the dams of the up-to-date structural designs, maintaining the face integrity is not guaranteed: cracks appeared in reinforced concrete faces at a number of high dams. Formation of cracks in faces should be attributed to presence of tensile stresses, whose values exceed concrete tensile strength. To prevent seal failure of the seepage-control element it is feasible to provide arrangement of the transverse joint in the face section where tensile stresses may be expected. Materials and methods. The studies were conducted on the example of a 100 m high dam with the aid of numerical modeling. Rockfill was considered as a lineally deformed material, but computations were conducted for a wide range of the soil linear deformation modulus: from 60 to 480 МPа. Steel reinforcement was considered in the face. Transverse joints were modelled with the aid of contact finite elements. Results. By the results of numerical modeling the tensile stresses appear in the uncut face due to bending deformations and deformations of longitudinal extension. The most hazardous is the face lower section. At this section the longitudinal tensile force and considerable moment are acting. Transverse joints are feasible to be arranged in this particular section of the face. Conclusion. It was revealed that the main positive effect of the transverse joint arrangement is in decreasing the value of longitudinal tensile force perceived by the face. Impact of the transverse joint on bending moments has a local effect and covers the section of the limited length. Moreover, at arranging joints the values of bending moments may increase. We may recommend arrangement of a transverse joint in the face which is parallel to the perimeter joints only in the face lower part which is subject to longitudinal deformation.

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