Non-uniform Loading Research Articles

Post-buckling behavior of rectangular multilayer FG-GPLRC plate with initial geometric defects subjected to non-uniform in-plane compression loads in thermal environment

A semi-analytical method is established to investigate post-buckling behavior of functionally graded graphene platelets reinforced composite (FG-GPLRC) plate with initial geometric defects under non-uniform in-plane compression loads. Buckling governing equations are derived base on a new unified framework of transverse shear deformation plate theory, and the reliability and accuracy of proposed method are validated. Parametric studies are systematically performed for the first time to elaborate the effects of GPLs, structural characteristics, initial geometric defects, loading cases and thermal environment on post-buckling behavior of FG-GPLRC plate. This article can provide theoretical guidance for the design and optimization of FG-GPLRC plate.

Dynamic instability analysis of perforated stiffened laminated composite panels subjected to non-uniform in-plane edge load under hygrothermal condition

A robust and computationally efficient finite element (FE) formulation has been developed in an effort to understand the parametric instability behaviour of a perforated stiffened composite panel subjected to a pulsating non-uniform edge load under a hygrothermal environment. The panel is modelled using a 9-noded heterosis element to avoid shear locking, whereas the stringer uses a 3-noded isoparametric beam element with a displacement compatibility condition employed at the skin–stringer​ interface. Due to the non-uniform distribution of stress in the perforated panel as a result of exposure to environmental and mechanical loading conditions, a unique dynamic technique has been implemented to account for the instability performance by employing two types of boundary conditions. In the current investigation, an unstiffened panel is initially obtained based on the highest value of the dynamic instability opening (DIO) and the unstable excitation frequency of the panel for different lamina schemes, cutout shapes, and loading conditions. The obtained unstiffened panel is further investigated for various stiffener configurations to determine a highly unstable perforated stiffened panel based on the DIO value and instability zone frequency range. Detailed parametric studies are then carried out considering the cutout sizes, cutout orientation, panel’s aspect ratio, and stiffener depth to understand the parametric instability behaviour of the panel in a hygrothermal environment. It is found that moisture significantly influences the dynamic instability behaviour of the perforated stiffened panel compared to the temperature exposure by shifting the instability zone towards the lower frequency. The width of the instability region of the stiffened panel broadens abruptly as the magnitude of the applied static in-plane edge load enhances. Also, for certain combinations of the dynamic and static load factors, the lower bound of the instability region reduces to zero, resulting in fluttering. In general, it is observed that stiffer the panel, wider is the instability zone with a higher unstable excitation frequency range.

Thermo-mechanical buckling analysis of thick beams reinforced with agglomerated CNTs with temperature-dependent thermo-mechanical properties under a nonuniform thermal loading

In this article, the thermo-mechanical buckling analysis of composite beams reinforced with carbon nanotubes (CNTs) subjected to a nonuniform thermal loading is studied. To increase the accuracy of results, the beam is modeled based on the quasi-3D sinusoidal shear deformation beam theory which considers shear deformation and thickness stretching. Temperature-dependent thermo-mechanical properties care considered for both polymeric matrix and CNTs. The CNTs are orientated randomly and distributed along thickness direction based on various symmetric and nonsymmetric patterns and agglomeration of CNTs is incorporated. The heat conduction equation is solved analytically to obtain the temperature profile along the thickness direction. The governing equations and associated boundary conditions regarding the thermo-mechanical analysis of the beam are derived using Hamilton’s principle and solved numerically using the differential quadrature method. Convergence and accuracy of the presented solution are confirmed, and the influences of various parameters on the thermo-mechanical stability regions are investigated, such as boundary conditions, thickness-to-length ratio, mass fraction and distribution pattern of the CNTs, and the CNTs agglomeration parameters. Numerical results reveal that to achieve the most expanded thermo-mechanical stability regions, it is more helpful to distribute the CNTs as far as away from the middle axis of the beam, especially near the surface with lower temperature. It is observed that neglecting the temperature-dependency of thermo-mechanical properties results in an overestimate of the critical temperature, and this overestimate is more noticeable for the beams with more constrained boundary conditions.

Nonlinear vibration responses of lattice sandwich beams with FGM facesheets based on an improved thermo-mechanical equivalent model

An investigation on the nonlinear vibration behaviors of a lattice sandwich beam with pyramidal truss core and functionally graded material (FGM) facesheets under thermo-mechanical loads is performed with consideration of the temperature-dependency of material properties. In present work, an improved equivalent methodology is proposed to determine the transverse shear modulus of pyramidal core subjected to a non-uniform thermal field across thickness direction and makes lattice truss core transformed to a continuous layer. Finally, the lattice sandwich beam is modeled as a three-layered sandwich structure. The facesheets are made of FGMs with mixture of ceramics and metals in a pow-law form. The outer surfaces of facesheets are ceramic-rich, while the inner surfaces are metal-rich. The nonlinear strain–displacement relations are established based on the von Kármán large deflection and classical beam theory. The Lagrange method are implemented to yield equations governing the free and forced vibration behaviors. With the help of Newton-Raphson iteration technique as well as the Newmark-β method, the nonlinear time-independent responses of the sandwich beam under thermal environment are solved. A comprehensive parameter study is directed to address the effects of non-uniform thermal environment, FMG facesheets, external load, and lattice core on the nonlinear vibrations of the beams.

Analytical Solution of the Grouting Reinforcement Response of a Circular Cavern in Deeply Buried Fractured Surrounding Rock under a Nonuniform Stress Field.

Grouting is widely utilized to reinforce fractured surrounding rock. However, presently, the secondary stress distribution of fractured surrounding rock after grouting is not distinct, which hinders the accurate evaluation of the grouting effect. Therefore, a complex variable function solution is provided for the evolution of the stress field and the displacement field around the reinforced fractured surrounding rock subjected to a nonuniform load. By comparing the evolution of the stress and radial displacement fields around the cavern, the reinforcement effect on the fractured surrounding rock is quantitatively confirmed. The results show that grouting has an obvious modification effect on fractured surrounding rock: its radial stress and circumferential stress fields are affected to different degrees, and the circumferential stress is more obvious. Grouting makes the circumferential stress peak transfer from the wall of the cavern to the roof and floor of the cavern, which is beneficial to the stability of the cavern. The radial displacement around the cavern also decreases. The displacement of the wall decreases by approximately 24.0%, and the radial displacement of the roof and floor decreases by approximately 61.8%.

Group Performance of Energy Piles under Cyclic and Variable Thermal Loading

Energy piles, a new type of heat exchanger that serves dual purposes, have gained increasing attention due to the growing energy demand and corresponding carbon emissions. Depending on intended operational requirements or by accident, energy pile groups may be subjected to cyclic and variable thermal loadings. This study presents the results from a series of full-scale field tests of a 2×2 energy pile foundation. The energy pile group was operated partially or fully during the tests to investigate the potential effects of cyclic nonuniform thermal loadings. The results indicated that the cyclic thermal loadings could induce an increase in compressive stress of piles at the end of the experiments. Further comparative analysis showed that the residual compressive stress was attributed mainly to the drag-down effects of the surrounding soil. The compressive stress induced by drag-down effects will overlap with the thermally induced stress, and thus lead to a more significant effect on the energy piles. If the drag-down effects are presented, the stress change may exceed the theoretical upper bound of thermal stress and may be underestimated. In addition, cyclic nonsymmetrical thermal loadings could induce accumulation of differential settlement and group tilt in the energy pile group. It was shown that the group tilt caused by cyclic and variable thermal loadings can be acceptable for general engineering structures. The group tilt will not accumulate further when subjected to symmetrical thermal loadings. A reasonable arrangement of operational piles still can be used to avoid unwanted group tilt generation.

Growth of nano-branches on 1-D WO3 nanotrees by flame process and its photoelectrochemical performances

Flame vapor deposition (FVD) is a powerful method to prepare rapidly and economically the nanostructured thin film with high purity and high crystallinity. One-dimensional (1-D) nanostructured tungsten oxide (WO 3 ) thin film has high potential for various applications as photocatalytic material and, in this study, was prepared from tungsten wire as a precursor by FVD process. The nucleation and growth rates in FVD process could be controlled by changing the precursor supply rate in flame instantaneously by installing additional wire traverse feeder and the nanotree structured WO 3 thin film was prepared successfully. The concentration of nano-branches at nanotree structured WO 3 thin films could be controlled by adjusting wire traversing speed. The proper wire traverse feeding speed could increase surface area and allow more light absorption by additional growth of nano-branches, but too low wire traverse feeding speed could make random and dense growth of nano-branches to reduce the electrical properties and total surface area. The proper growth of nano-branches could increase the photoelectrochemical (PEC) performance of WO 3 /BiVO 4 heterojunction thin film by providing the larger interfacial contact area for heterojunction, but too much growth of nano-branches could reduce the PEC performance because of non-uniform loading of BiVO 4 in WO 3 thin film during spin-coating process. This study can be a basis to prepare by FVD process not only the nanotree structured WO 3 thin film for its PEC application but also many nanostructured thin films of various materials for their suitable applications. • Nanotree structured WO 3 thin film was successfully prepared by 1-step flame process. • The precursor concentration could be changed sharply by the wire traversing feeder. • Nucleation and growth rates were controlled to prepare nano-branches on nanotrees. • Nanotree structured WO 3 /BiVO 4 film improved photoelectrochemical performance. • Proper growth of nano-branch is important for high photoelectrochemical performance.

Influence of porosity and nonuniform in-plane edge loads on vibration and buckling response of power law and sigmoid function based FG sandwich plates with geometrical discontinuities

Porosity defects can emerge during the manufacturing process of Functionally Graded Sandwich Plates (FGSPs). In practice, FGSPs have geometric discontinuities/cutouts and are exposed to Nonuniform In-plane Edge Loads (NIELs). The presence of porosity, cutout and NIELs causes a significant reduction in the stiffness of the plate affecting its vibration and buckling behavior. Therefore, in this paper vibration and buckling results obtained using the Finite Element (FE) method hitherto not reported in the literature are presented for porous FGSPs with cutouts and subjected to NIELs. Four types of porosity distribution models are explored, and the porosity imperfections are modeled as the criteria of stiffness reduction. Porosity-dependent material properties of FGSPs are evaluated using modified power law and sigmoid function. The current study incorporates two distinct kinds of sandwich configuration in such a way that there is no material mismatch along the thickness direction. The application of different cases of NIELs on the plate with cutouts leads to the development of nonuniform stresses. Hence a novel dynamic approach has been proposed to evaluate buckling loads by implementing two sets of boundary conditions. The first set of boundary conditions calculates pre-buckling stress, while second set calculates critical buckling loads. The generated results from the current FE formulation are compared with existing results in the literature to ensure accuracy. Finally, the effect of porosity distribution, NIELs, cutout ratio and its positions, support conditions, volume fraction exponents and geometric parameters on the vibration and buckling response are studied and discussed to arrive at appropriate conclusion.

Numerical simulation of elastic buckling in 3D concrete printing using the lattice model with geometric nonlinearity

This paper explores buildability quantification of randomly meshed 3D printed concrete objects by considering structural failure by elastic buckling. The newly proposed model considers the most relevant printing parameters, including time-dependent material behaviors, printing velocity, localized damage and influence of sequential printing process. The computational uniaxial compression tests were first conducted to calibrate age-dependent elastic modulus and yield stress. Subsequently, analyses of the 3D printing process of a free wall structure and a square layout were performed. The model can reproduce the asymmetry of buckling failure accurately and the predicted critical printing height is in excellent agreement with experimental data from the literature. It can be concluded the combined effect of material variability and non-uniform gravitational loading due to sequential printing process resulted in structural failure during 3D concrete printing. Using this model, printing parameters can be optimized and a suitable printing scheme can be devised to improve structure buildability.

Research on casing deformation mechanism and prevention measures based on micro-seismic signal distribution

Casing deformation is a severe problem in shale gas well development. The field data show that multiple deformations usually occur in the same casing well, and the distance is close, and the degree of deformation is different. In this paper, firstly, based on the distribution of micro-seismic event points in the Ning M well, the fracture group is inverted, and to establish the finite element numerical model to simulate the multi-stage fracturing, Then, the stress at each point of the casing is analyzed with the fracturing time, the circumferential stress at each point after fracturing and the axial stress of casing, and the displacement variation of casing in the directions of maximum, minimum and vertical principal stress are discussed. Finally, the effect of the intensive fracturing technology on controlling casing deformation is discussed. The results show that: a) Casing stress increases in different amplitude at a local point, circumferential direction, an axial direction, and regional stress difference is formed; b) Some local areas around the wellbore are subjected to twice or more re-fractures, and the corresponding rock properties (such as elastic modulus and Poisson's ratio) will change differently; c) Casing deformations with different directions and displacements appear in some reconstructed areas, showing “S” shape deformation, consistent with the actual deformation situation on site; d) The intensive fracturing technology can alleviate the non-uniformity of fracturing and reduce the non-uniform load of the casing, and effectively reduce the casing deformation rate after field application.

High-velocity impact response of cylindrical tubes with linear gradient grooves: A comparative study

Grooved tubes benefit from optimized energy absorption characteristics compared to regular tubes. This paper investigated the crashworthiness characteristics of cylindrical tubes with various types of grooves under high-speed impact loads. Furthermore, the dynamic load response of tubes with external grooves having linear thickness distribution was studied experimentally and numerically for the first time. To assess the performance of gradient grooved tubes (GGTs), the crashworthiness of typical cylindrical specimens and tubes having internal or external grooves with uniform thickness distributions was compared. The results showed that the dynamic crush mode of GGTs was axisymmetric, progressive, and sequential. Furthermore, the mean crushing force (MCF) in GGT tubes was considerably less compared to other tubes (e.g., 89% difference between GGT and non-gradient tube). Moreover, the initial peak forces of all types of tubes having the same number of grooved sections were almost in the same range. However, the crushing force efficiency of GGTs was remarkably lower than other tubes due to their non-uniform load response. The numerical results showed that by increasing the number of grooves in GGTs, peak force, energy efficiency, and axial shortening decreased, but mean crushing and overall crushing forces increased. Altogether, the highest energy efficiency belonged to the GGT specimens, in which 17%, 4.2%, and 96% increases were observed compared to external and internal groove tubes and typical cylindrical tubes, respectively. Also, the energy efficiency increased with the number of grooves.

Numerical simulation of snowdrift on an air-supported membrane structure and response analysis under snow loads

The air supported membrane structure is a typical nonlinear flexible long-span space structure, the wind-induced drift and the resulting accumulation and distribution of snow particles on the structure may be the primary design concern among all loads in heavy-snowfall region. Thus, an accurate prediction of snow distribution on membrane surface is vital to structural design. A numerical simulation method is used to estimate snowdrift in this paper. Based on Euler-Euler method in multi-phase flow theory, this numerical model adopted Mixture model and combined with the snow deposition and erosion model, the snowdrift on an air-supported membrane coal shed is simulated, the distribution factor for roof snow load is given under different wind speed and different directions to estimate the worst load case, snow load on the air-supported membrane structure is significantly affected by snowdrift which causes significant non-uniform snow load. Furthermore, the response analysis of the air-supported membrane structure under snow load is studied, for comparison, uniform snow load case, non-uniform snow load case, and simulated snow load case under 0° wind direction are all considered. The results show that non-uniform snow load caused by snow drifting is more dangerous and should be considered.

Investigation into the evolution of the microcosmic surface of bainitic wheel steel material suffering polygonal wear

With the rapid development of high-speed railway, it is imperative to develop highly comprehensive wheel/rail materials to improve the safe and stable operation of trains. Even though bainitic steel shows excellent resistance to rolling contact fatigue (RCF), its wear resistance is not good enough and whether it is qualified for high-speed wheel materials still needs further investigation. Through conducting rolling wear experiment on carbide-free bainite (FCB) wheel steel, this paper observed the changes of the surface profile lines of the worn specimens regularly and the wear morphology in different stages, and analyzed the changes of the microstructures and hardness on the surface layer, in order to explore the formation of polygonization wear (PolyW) from the angle of the microcosmic surface of bainitic wheel steel. The research revealed that during the process of rolling wear, the nonuniform load caused by mechanical vibration could lead to the appearance of PolyW on the surface of the two-disc specimens of FCB wheel steel. Based on the surface morphology and size variations, three stages could be divided to explain the formation of PolyW: The incubation stage where macromorphology underwent cyclic changes, the development stage where PolyW appeared in some regions and the mature stage where PolyW spread all over the circumference. The wear mode in wave crests was mainly featured by oxidative wear and adhesion wear, and the one in wave troughs was marked by fatigue wear with wear rotations increasing, PolyW on the surface was exacerbated. Compared with wave crests, wave troughs had a larger slip ratio and the additional impact load, so the microstructures experienced severer deformation, the hardness increase was higher and the depth of the hardening layer was greater.

Strength analysis of perforated casing in ultra-deep horizontal shale wells during sublevel acidizing and hydraulic fracturing process

In the process of sublevel acidizing and fracturing, the non-uniform load on production casing is complex, and casing failure occurs frequently, which seriously affects the next step of production, stimulation, and underground safety of the oil and gas well. Aiming at the deformation and failure problem of perforated casing in ultra-deep horizontal wells, residual strength analysis and safety evaluation of directional perforated casing under sublevel acidizing and fracturing conditions were carried out. Due to the large scale difference between the underground formation and casing and the complex geometry of the model, an indirect coupled two-step method was proposed to determine the external load of casing first and then calculate its mechanical strength. By using this method, the stress level and distribution of perforated casing in in-situ stress field of X well are determined, and the safety factor of casing is analyzed. On this basis, considering the redistribution of in-situ stress field in the sublevel acidizing and hydraulic fracturing process, the stress situations on perforated casing under different in-situ stress differences are studied, and the measures to prevent casing failure are given. The proposed calculation method can provide references for casing selection and perforation process design of ultra-deep horizontal wells.

Minimization of dies volume using uniform distribution of hollows in the conditions of multi-cycle fatigue dependence on temperature

The research is devoted to development of a model of dies of optimized shape used in the field of metal forming. Use of solid-cast metal dies at the present stage of production requires large material resources, which makes it actual to develop dies models with minimal volume of material due to effective distribution of hollows in correspondence with the required strength resource. The dies mainly experience compressive non-uniform loading in the conditions of drawing and forming, which can lead to the accumulation of damages and lowering of its strength resource in the conditions of long-term operation of a die at high temperatures; therefore, the optimized area is represented in this work by alternating rod elements and hollows. The paper considers the problem of optimizing the volume of a metal die, presents a model for minimizing the die volume with restrictions on multi-cycle fatigue at various temperature conditions. The dependence between the volume of the optimized area and the number of loading cycles is obtained, taking into account the non-uniform loading of the die for axisymmetric forming. The main approach to reducing the die volume due to distribution of hollows was concluded in increase the stress state of the rod elements experiencing compressive stress to the limit values in accordance with the restriction on multi-cycle fatigue. The number of elements providing the required die stress state is calculated for different temperature conditions and preset geometrical parameters of the rod elements. When calculating the configuration of the optimized die area for axisymmetric forming, experimental curves of dependence between stress state and number of cycles for 12Kh1MF1 steel were considered at the constant temperature. The variants of the material distribution in the internal die area at preset temperatures are presented. Reduction of the optimized die volume was compared with a solid cast die. The constructed mathematical model and the results of calculation of the optimized die volume will significantly reduce the material costs for production of metal forming dies and can be used for further development of the methods for topological optimization of stamping tools, taking into account the features and duration of power and thermal loading. The research was carried out under financial support of the Russian Foundation for Basic Research within the framework of the scientific project No. 19-38-60020\19 “Development of optimization model for dies of stamping accessories via the method of efficient material redistribution”.

A Novel Nonlinear Elasticity Approach for Analysis of Nonlinear and Hyperelastic Structures

There are many materials that the linear elasticity theory cannot predict their mechanical behavior against applied loads. This research proposes a comprehensive theoretical method to obtain the mechanical response of hyperelastic models (with nonlinear elastic deformations) such as polymers and rubbers. They are vital in the design phase of complicated engineering structures like engine mounts and structural bearings in aerospace and automotive industries. The presented theory is implemented in detail and has no limitations in analyzing geometrically and physically nonlinear materials. As a test case, the governing equations of a sheet made of nonlinear elastic material are derived within the framework of this new approach. The derived governing equations are completely nonlinear in all major directions. Consequently, results can be one of the most accurate mathematical simulation results for nonlinear elastic material structures. Then, the obtained equations are solved using a meshless solution method named the semi-analytical polynomial method. The stress and deformation results of the structure under uniform and non-uniform transverse external loadings are obtained for different types of boundary conditions, loading, and material properties. Consequently, this research can be widely used as a suitable essential reference for researchers studying the mechanical behavior of nonlinear elastic structures.

SAFETY REQUIREMENTS FOR SNOW LOAD ON UNIQUE TRANSPORT INFRASTRUCTURE FACILITIES

Introduction: Wind-induced snow drift is the main reason behind the non-uniform snow load on a snow-covered area. As known, snow load poses a serious hazard to the roofing of buildings and structures. According to the applicable regulatory documents, snow loads for non-standard roofs must be determined based on the results of model tests in wind tunnels. Purpose of the study: We aimed to study snow load on a unique transport infrastructure facility — the world’s first crossborder cable car connecting Blagoveshchensk in Russia to Heihe in China. Methods: We performed model tests to study snow accumulation and drifting with the use of a unique research setup — the Large Gradient Wind Tunnel, courtesy of the National Research Moscow State University of Civil Engineering. Results: Based on climate analysis and tests under different wind attack angles, we obtained distribution patterns for snow deposits on the roofing of the unique transport infrastructure facility under consideration and derived the values of the coefficient μ (the coefficient of transition from the weight of the snow cover on the ground to the snow load on roofing).

Dynamic Response of Lining Structure in a Long Tunnel with Different Adverse Geological Structure Zone Subjected to Non-Uniform Seismic Load

The damage of a long tunnel is found in parts with an adverse geological structure zone under an earthquake. The phenomenon is normally the consequence of a non-uniform seismic load. Thus, to reveal the mechanism of the phenomenon, the dynamic response of the lining structure in a long tunnel passing through an adverse geological structure zone subjected to a non-uniform seismic load is mainly studied in this paper. Firstly, based on the random ground motion synthesis theory, the non-uniform ground motion acceleration–time history curves that reflect local site effects, such as traveling wave effects and attenuation effects, are generated. Secondly, the behavior of the tunnel with a different adverse geological structure zone (including different inclinations, thicknesses, and lithologies) under non-uniform seismic input is studied. Then, the impact of the different adverse geological structure zone on the internal force and safety factor of the tunnel lining is analyzed. Finally, the failure characteristics of the lining structure in the tunnel crossing through the adverse geological structure zone subjected to a non-uniform seismic load are revealed. The results show that the seismic dynamic responses significantly increase under non-uniform seismic input compared with the results under uniform seismic input, and the dynamic responses distribution along the tunnel axial is distinctly different under non-uniform seismic input. The inclination and thickness of the adverse geological structure zone have a significant influence on the internal force and safety factor of the tunnel lining, while the lithology mainly acts around the adverse geological structure zone. When the inclination angle of the adverse geological structure zone is 45°, a large number of compression-bending cracks appear in the entrance and exit sections of the tunnel, and the tunnel is in the most dangerous state.

Postbuckling and postbuckled vibration behaviour of imperfect trapezoidal sandwich plates with FG-CNTRC face sheets under nonuniform loadings

The present work investigates the postbuckling, and postbuckled vibration behaviour of initially imperfect trapezoidal sandwich plates with functionally graded carbon nanotube reinforced composite (FG-CNTRC) face sheets and FG porous metal foam core under the influence of non-uniform edge compression. The plate's kinematic assumptions are based on a refined higher order theory and the strain-displacement relations include von Karman assumptions for geometrical nonlinearity. The weak form of governing equations derived using Hamilton's principle is transformed into a discretized form of algebraic equations using the element free Galerkin (EFG) method in conjunction with moving kriging (MK) interpolation functions. The pre-buckling stresses are determined using static analysis to evaluate accurate critical buckling loads. Modified Riks technique is used to trace nonlinear equilibrium paths. Parametric studies include the effect of CNT distribution in face sheets, porosity distribution in the core layer and edge loading conditions on the nonlinear stability and vibration behaviour of sandwich plates. New results on trapezoidal sandwich plates with initial imperfections, hitherto not found in the literature, are presented for the first time, which can be used as benchmark solutions for further research.

THE EFFECTIVE STRUCTURES OF REINFORCED CONCRETE FOUNDATION OF SYLOSES AT GRAIN TRANSFER TERMINALS

To date sea, river and railroad terminals with metallic vertical cylindrical silos as technological equipment are used to transfer cereal and oil crops. Designs of reinforced concrete buried foundations with underground galleries and foundations with overground under-silo storey that are arranged for cylindrical metallic silos of high capacity have been investigated. The main criterion that requires strict observance is not to exceed the allowable value of settlement of metallic silos. Also, because the construction of silo is sensitive to nonuniformity of deformations, the criterion of uniformity of settlements within the boundaries of foundation shall be observed. Analysis of factors of silo accidents has shown that their considerable number occur as the result of destruction of metallic construction of silos by nonuniform operational loads caused by asymmetric actions during emptying silo. Nonuniform above-the-norm deformations of foundations also quite frequently cause silo accidents. Foundations of metallic silos of transfer terminals cause considerable loads on the base. Natural soil base is not always capable of taking stress under the foot of foundation. This is being solved by strengthening foundation bases: by making soil cushion, reinforcing the base with the more strong and rigid elements, injecting mineral or polymeric binders. Pile foundations are quite common during building silos. But their use is not always economically reasonable and justified in particular geological conditions of the building site. Rigidity parameters of the base essentially influence stressed-deformed state of foundations of metallic silos of increased diameters and distribution of contact stresses under the foot of foundations. Deformation parameters of the base and the construction of foundation create the possibility to regulate settlements and deflections of foundation. This makes it possible to control distribution of contact stresses. The value and character of settlement of round slab foundation of silo depend on the values of operating loads, dimensions and depth of foundation laying, distributional properties of its design, geological conditions of the base, influence of loads from the neighboring structures. Application of numerical methods of simulation of combined operation of base-foundation-structure to assess stressed-deformed state of silo foundations proves that prospective trend of improvement of design solutions of silo foundations is application of their prestressing. This causes increase in foundation rigidity and positively influences its stressed-deformed state.