scholarly journals STRESS-STRAIN STATE OF PREFABRICATED MONOLITHIC BENDING ELEMENT AT GRADUAL INSTALLATION AND LOADING

2019 ◽  
pp. 101-114
Author(s):  
A. A. Koyankin ◽  
V. M. Mitasov ◽  
I. Ya. Petuhova ◽  
T. A. Tshay
Keyword(s):  
Bearing Capacity ◽  
Strain State ◽  
Concrete Strength ◽  
Experimental Models ◽  
Stress Strain ◽  
Load Bearing Capacity ◽  
Total Load ◽  
Load Bearing ◽  
Regulatory Documents ◽  
Stress Strain State

The stress-strain state of the prefabricated monolithic element depends on its gradual installation and loading. Regulatory documents of the Russian Federation indicate the need to calculate precast-monolithic structures for two stages of construction: before and after the specified monolithic concrete strength acquired. In this case, the stress-strain state that appeared in the prefabricated elements before the specified monolithic concrete strength should be considered.  However, the construction and loading stages at issue and accumulation of stresses and strains are not disclosed in the regulatory documents. In addition, this problem is insufficiently studied.  In this regard, the aim of this paper is to study the pre-loading effect of the prefabricated element on its stress-strain state and the load-bearing capacity.  During the experiments, a pre-loaded prefabricated part is studied. The obtained results are compared with instantaneously loaded test samples. Other parameters of the experimental models are completely identical. In all, 5 samples are tested (step-by-step loading of 3 samples and instantaneous loading of 2 samples).  It is shown that pre-loading of the preloaded prefabricated part significantly affects the stress-strain state of the whole structure and its total load-bearing capacity.  

scholarly journals Research into rock mass geomechanical situation in the zone of stope operations influence at the 10th Anniversary of Kazakhstan’s Independence mine

2021 ◽  
Vol 15 (1) ◽  
pp. 103-111
Author(s):  
Azamat Matayev ◽  
Ainash Kainazarova ◽  
Ibatolla Arystan ◽  
Yerkebulan Abeuov ◽  
Arman Kainazarov ◽  
...  
Keyword(s):  
Rock Mass ◽  
Bearing Capacity ◽  
Strain State ◽  
Stability Margin ◽  
Principal Stresses ◽  
Stress Strain ◽  
Load Bearing Capacity ◽  
10Th Anniversary ◽  
Stress Strain State ◽  
Mine Workings

Purpose. Predicting the stress-strain state (SSS) of the rock mass in the zone of stope operations influence using the self-caving mining system and the calculation of the load-bearing capacity of mine workings support at the 10th Anniversary of Kazakhstan’s Independence mine. Methods. An engineering-geological data complex of the host rocks properties has been analyzed. Numerical modelling of the rock mass stress-strain state and the calculation of the load-bearing capacity of the support types used at the mine have been performed with the help of the RS2 software. This program, based on the Finite Element Method in a two-dimensional formulation, makes it possible to take into account a significant number of factors influencing the mass state. The Hoek-Brown model with its distinctive advantage of nonlinearity is used as a model for the mass behaviour. Findings. The values of the main stresses and load on the support have been obtained. According to the numerical analysis results of the rock mass stress-strain state at a depth of 900 m (horizon -480 m), the principal stresses are close to hydrosta-tic ones σ1 = σ2 = σz = 24.8 MPa. Predicting assessment of mine workings stability margin is performed before and after stope operations. Based on its results, it can be assumed that the stability margin of the mine workings driven in the stope zone is below the minimum permissible, therefore, caving and an increase in the load on the support are possible. Abutment pressure on mine workings support at a mining depth of 900 m (-480 m) has been calculated. The parameters of support in mine workings driven at the horizon -480 m have been calculated. Originality.The nature and peculiarities of patterns of the stress-strain state formation within the boundaries of various stope operations influence in blocks 20-28 at the horizon -480 m have been determined. The quantitative assessment of the values of loads on the support of haulage cross-cuts of the horizon mining is given. Practical implications. The research results can be used for creating a geomechanical model of the field and to design stable parameters of mine workings support. Keywords: stress-strain state, principal stresses, support, mine, ore, rock mass

scholarly journals CONTROL OF ACTIONS OF STEEL TANK IN WORKING

2018 ◽  
Vol 22 (4) ◽  
pp. 66-74 ◽  
Author(s):  
A. A. Vasilkin
Keyword(s):  
Strain State ◽  
Low Cycle Fatigue ◽  
Operating Conditions ◽  
Maximum Effect ◽  
Safe Operation ◽  
Stress Strain ◽  
Load Bearing ◽  
Stress Strain State ◽  
Steel Tank ◽  
Steel Tanks

In steel tanks made by the method of rolling, defects of a geometric shape often occur in the area of the welded welded joint of the wall. Subsequently, in these areas, as a result of low cycle fatigue, an unacceptable defect appears in the form of a crack, which makes it necessary to remove the reservoir from operation and carry out a set of measures for its repair. To determine the terms of safe operation of vertical steel tanks with geometric defects, it is proposed to use the methodology control of the actions of structures of load-bearing structures, one of the directions of which is the regulation of the stress-strain state of steel structures. To implement the possibility of regulating construction, it is necessary to identify such parameters, the change of which will give the maximum effect in achieving the set goals. As the indicated parameters, the design characteristics (material properties, design scheme, geometric characteristics) and factors of external influences (load, operating conditions) can act. To regulate the stress-strain state design of vertical steel tanks, the following regulators are proposed: product loading height, wall deflection arrow and permissible number of tank loading cycles. By numerical calculation of the VAT of the vertical steel tank design with geometric defects, the necessary values and values of the stress state are determined. Further, using known analytical dependencies from the field of fracture mechanics, it is possible to determine the permissible number of loading cycles of the reservoir before the appearance of a crack-like defect. The application of the methodology control of the actions of structures load-bearing structures, by means of a certain change in the established control parameters, allows increasing the number of loading cycles of the reservoir, thereby increasing the period of safe operation of the defective reservoir and thereby increasing the economic efficiency of the tank farm.

scholarly journals Influence of the concrete strength and the type of supports on the stress-strain state of a hyperbolic paraboloid shell footbridge structure

2021 ◽  
Vol 17 (4) ◽  
pp. 379-390
Author(s):  
David Cajamarca-Zuniga ◽  
Sebastian Luna
Keyword(s):  
Thin Shell ◽  
Strain State ◽  
Concrete Strength ◽  
Design Parameters ◽  
Live Load ◽  
Structural Behaviour ◽  
Stress Strain ◽  
Hyperbolic Paraboloid ◽  
Element Analysis ◽  
Stress Strain State

Relevance. This work is the first in a series of publications on the selection of a suitable analytical surface for implementation as a self-supporting structure for a thin shell footbridge. The study on the influence of concrete strength, live load position and support types on the stress-strain state of a hyperbolic paraboloid (hypar) shell is presented. Objective - to define the initial design parameters such as the appropriate concrete strength and the support type that generates the best structural behaviour to perform the subsequent structural design of a thin shell footbridge. Methods. The static finite element analysis was performed for 4 compressive strengths of concrete (28, 40, 80, 120 MPa) which correspond normal, high and ultra-high resistance concrete, 5 different live load arrangements and 3 different support conditions. Results. The shell model with pinned (two-hinged) supports shows the same vertical displacements as the model with fixed supports (hingeless). For the studied shell thickness, in terms of stress behaviour, the model with pinned ends is more efficient. The combination of two-hinged supports with 80 MPa concrete strength shows a better structural performance.

scholarly journals Settlement and bearing capacity of water-saturated soils of foundations of finite width under static impact

Vestnik MGSU ◽  
2021 ◽  
pp. 463-472
Author(s):  
Zaven G. Ter-Martirosyan ◽  
Armen Z. Ter-Martirosyan ◽  
Ahmad Othman
Keyword(s):  
Bearing Capacity ◽  
Strain State ◽  
Water Saturation ◽  
Strength Properties ◽  
Finite Width ◽  
Stress Strain ◽  
Linear Deformation ◽  
Stress Strain State ◽  
Linear And Nonlinear ◽  
Water Saturated

Introduction. In case of brief exposure to static loads or dynamic loads, in conditions of absence of drainage, distribution of total stresses between the skeleton of soil and pore gas-containing water should be taken in account. The situation of the stress-strain state of the base is further complicated when we consider the degree of water-saturation of soil of the foundation (0.8 < Sr ≤ 1). The aim of the study is to pose and solve problem of the stress-strain state of a water-saturated soil massif, Including settlement and bearing capacity of a water-saturated base of a foundation of finite width, depending on the degree of water saturation of soils, taking into account the linear and nonlinear properties of the skeleton of soil and the compressibility of pore gas-containing water. Materials and methods. Henckyʼs system of physical equations are used as a calculation model to describe the relationship between deformation and stresses of soil, which takes into account the influence of the average stress on the deformation and strength properties of the soil. This system allows us to represent the linear deformation of the soil as the sum of the volumetric and shear components of the soil of this deformation. In addition allows us too to determine the deformation of the layer of soil, as part of the compressible thickness of the base of foundation with finite width under conditions of free deformations. Results. Depending on the linear and nonlinear deformation parameters, the settlement can be developed with a damped curve (S – p) and stabilize, and can be developed with a non-damped curve (S – p) and moved to the stage of progressive settlement. Conclusions. Solutions have been made for cases when the water-saturation of the base soils changes in the range of 0.8 to 1.0. It is shown that the settlement and bearing capacity of a water-saturated base significantly depends on the degree of water saturation of soils.

scholarly journals Assessment of the mutual influence of deformation-strength characteristics of the fastening system elements

2019 ◽  
Vol 123 ◽  
pp. 01006 ◽  
Author(s):  
Iryna Kovalevska ◽  
Zenon Pilecki ◽  
Oleksandr Husiev ◽  
Vasyl Snihur
Keyword(s):  
Mine Working ◽  
Strain State ◽  
Mutual Influence ◽  
Strength Characteristics ◽  
Stress Strain ◽  
Load Bearing ◽  
Stress Strain State ◽  
Operation Modes ◽  
Mine Workings ◽  
Rigid Element

The degree of influence has been determined of diversified deformation-strength characteristics of load-bearing elements in the fastening system of the preparatory mine workings, while maintaining them in a laminal massif of soft rocks. The analysis has been performed of multivariate computational experiments of the stress-strain state of the load-bearing elements of the fastening system in the preparatory mine workings from the position of the mutual influence of their deformation-strength characteristics and the support loading as a whole. An analysis is represented of the mutual influence of the operation modes of the mine working support elements between themselves and the fastening system as a whole; it has been studied the stress-strain state of the mine working fastening system with a central hydraulic prop stay, as well as a significant increase in reliability of the support performance has been analysed and determined. The tendency has been substantiated of minimizing the load on the mine working fastening system – increasing the coherence of the diversified operation modes of fastening elements by enhancing preferentially the yielding property of the rigid element. The application has been substantiated of the central yielding prop stays of the strengthening support of a frame in case of intensive rock pressure manifestation in the zone of the stope works active influence.

scholarly journals Fire Performance of Columns Made of Normal and High Strength Concrete: A Comparative Analysis

2016 ◽  
Vol 711 ◽  
pp. 564-571 ◽  
Author(s):  
Thomas Gernay
Keyword(s):  
Bearing Capacity ◽  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Strength Loss ◽  
Fire Performance ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Strength Concrete ◽  
The Impact

The use of high strength concrete (HSC) in multi-story buildings has become increasingly popular. Selection of HSC over normal strength concrete (NSC) allows for reducing the dimensions of the columns sections. However, this reduction has consequences on the structural performance in case of fire, as smaller cross sections lead to faster temperature increase in the section core. Besides, HSC experiences higher rates of strength loss with temperature and a higher susceptibility to spalling than NSC. The fire performance of a column can thus be affected by selecting HSC over NSC. This research performs a comparison of the fire performance of HSC and NSC columns, based on numerical simulations by finite element method. The thermal and structural analyses of the columns are conducted with the software SAFIR®. The variation of concrete strength with temperature for the different concrete classes is adopted from Eurocode. Different configurations are compared, including columns with the same load bearing capacity and columns with the same cross section. The relative loss of load bearing capacity during the fire is found to be more pronounced for HSC columns than for NSC columns. The impact on fire resistance rating is discussed. These results suggest that consideration of fire loading limits the opportunities for use of HSC, especially when the objective is to reduce the dimensions of the columns sections.

scholarly journals Mathematical modeling of stress-strain state of elements of joints of wooden structures on glued fiberglass washers

2021 ◽  
Vol 2131 (3) ◽  
pp. 032095
Author(s):  
M V Ariskin ◽  
D O Martyshkin ◽  
I V Vanin
Keyword(s):  
Mathematical Modeling ◽  
Bearing Capacity ◽  
Strain State ◽  
Single Component ◽  
Stress Strain ◽  
Design Models ◽  
Stress Strain State ◽  
Deformed State ◽  
Wooden Structures

Abstract Design models of single-component and three-component samples were developed on glued fiberglass washers in order to investigate the stress-strain state (SF) of the elements of joints of wooden structures. The picture and the nature of the actual stressed-deformed state of the wooden element with glued washers are obtained. Quite high bearing capacity of wooden structures connection is shown.

scholarly journals STUDY OF STRESSED-DEFORMED STATE OF THE POLYGONAL ARCH COVERINGS OF WOOD

World Science ◽  
2019 ◽  
Vol 1 (1(41)) ◽  
pp. 11-14
Author(s):  
O. V. Boіko ◽  
A. O. Boiadzhi ◽  
O. M. Korshak
Keyword(s):  
Strain State ◽  
Stress Strain ◽  
Load Bearing ◽  
Special Steel ◽  
Stress Strain State ◽  
Deformed State

In this work the use of wooden I-beams with OSB wall as the load bearing elements for polygonal arch coverings of buildings of various spans are considered. Special steel connecting pieces can shape the polygonal arch coverings. Calculations of the constructions with a span of 12 and 18 meters and an analysis of their stress-strain state are given.

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