scholarly journals Experimental research on the haulage drifts stability in steeply dipping seams

2021 ◽  
Vol 15 (4) ◽  
pp. 56-67
Author(s):  
Ihor Iordanov ◽  
Ihor Buleha ◽  
Yaroslava Bachurina ◽  
Hennadii Boichenko ◽  
Vitaliy Dovgal ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Mine Working ◽  
Experimental Studies ◽  
Load Bearing Capacity ◽  
Mining Site ◽  
Load Bearing ◽  
Deformation Properties ◽  
Mine Workings ◽  
Coal Pillars ◽  
Protective Structures

Purpose. Substantiation of the conditions for haulage drifts stability using different protection methods in steeply dipping seams based on a set of experimental studies. Methods. To achieve the purpose set, mine instrumental observations have been performed to study the rock pressure manifestations in zonal advance workings adjacent to the stope face on the haulage horizon. The conditions for their maintenance, within the mining site, are assessed by the side rocks convergence value on the drift contour and the change in the cross-sectional area, taking into account the deformation properties of the protective structures. Findings. It is recorded that in the zone of the stope works influence, in the most difficult conditions, haulage drifts are maintained, when coal pillars or clumps of prop stays are used for their protection. It has been determined that a decrease in the section of such mine workings up to 50% is the result of the protective structures destruction. When protecting the hau-lage drifts with the rolling-on chocks, a decrease in the mine working section up to 30% occurs in the process of the protective structures compression. It has been revealed that deformation of coal pillars or clumps of prop stays up to 10-20% leads to a loss of their stability, and an increase to 60% leads to a complete loss of their load-bearing capacity, intensification of rock displacements on the mine working contour and deterioration of its stability. It has been determined that in the process of deformation of the rolling-on chocks from sleepers by 20-60%, they are compressed without loss of load-bearing capacity, which ensures a smooth deflection of the overhanging stratum and restriction of rock displacements on the haulage drift contour. Originality. To study the deformation characteristics of protective structures above the drift, the function of the increment is used of side rock displacements on the haulage drift contour along the mining site length dependent on the relative deformations of protective structures, which makes it possible to assess the real dynamics of the process. Practical implications. When mining steep coal seams, using the specificity of geomechanical processes, which are manifested in an anisotropic coal-rock mass during unloading, satisfactory mine workings stability can be ensured by changing the deformation properties of protective structures above the drift.

scholarly journals DETERMINATION OF THE AMOUNT OF ADHESION OF BASALT-PLASTIC REINFORCEMENT TO CONCRETE

2020 ◽  
Vol 8 (3) ◽  
pp. 36-39
Author(s):  
Yulia Kustikova
Keyword(s):  
Bearing Capacity ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Load Bearing Capacity ◽  
Load Bearing

The results of experimental studies and tests of concrete structures with basalt-plastic reinforcement to determine the load-bearing capacity, as well as the mechanism of adhesion of basalt-plastic rods to concrete are considered.

scholarly journals EXPERIMENTAL INVESTIGATION OF LOAD-BEARING CAPACITY AND DEFLECTIONS OF FULL-SCALE GLUED LAMINATED TIMBER BEAMS

2020 ◽  
Vol 2 (61) ◽  
pp. 5-11
Author(s):  
S. Shekhorkina ◽  
◽  
К. Shliakhov ◽  
А. Sopilniak ◽  
◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Strength Class ◽  
Failure Load ◽  
Timber Structures ◽  
Load Bearing Capacity ◽  
Concentrated Load ◽  
Load Bearing ◽  
Glued Laminated Timber ◽  
Deformation Properties ◽  
Timber Beams

With the transition to the design of timber structures in accordance with European standards, problems arise in assessment of the load-bearing capacity of glued timber structures that are caused by insufficient amount of data about the physical, mechanical and deformation properties of glued timber, which is produced in Ukraine. The aim of the work was to determine the load bearing capacity in bending and deflection of a glued timber beam under the action of a concentrated load in the middle of the span. Two glued laminated timber beams were used in the experiment. Both beams were made using lumber from pine wood and a moisture-curing onecomponent polyurethane adhesive Kleiberit PUR 510 FiberBond. The beams have the dimensions of the cross-section: width of 120 mm and height of 180 mm. The length of the beams was 9880 mm. Each beam consisted of 9 layers of 20 mm thick lamellas glued together. Considering the absence of the data on the strength class of the beam material, the theoretical load bearing capacity and deflection were determined according to the characteristics of the GL24h class (minimum strength class), and amounted to 722 kgf and 19.1 cm, respectively. As a result of the tests, the failure load and the deflection of the beams were determined, and the dependences of the deflection on the load were obtained. The actual deflection of the beams determined was 251 mm and 275 mm, which is 1.31 and 1.44 times higher than the predicted deflection. Accordingly, the failure load determined experimentally is 1.96 and 2.03 times higher than the theoretical value. During the tests, the features of the deformation and the nature of the destruction of the beams were investigated. Wherein, the determining factor was the presence of defects in timber and lamellas joints along the length in the most stressed layers. Based on the data obtained, recommendations on manufacturing aimed at the increasing the bending strength of glued laminated timber beams are given. The results obtained will be further used in the development of structural solutions for hybrid timber-concrete floors.

Role of Collagen Content and Architecture in the Load Bearing Capabilities of Tissue-Engineered Cartilage

2011 ◽  
Author(s):  
M. Khoshgoftar ◽  
C. C. van Donkelaar ◽  
K. Ito
Keyword(s):  
Bearing Capacity ◽  
Network Architecture ◽  
Mechanical Performance ◽  
Experimental Studies ◽  
Limiting Factor ◽  
Collagen Network ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Native Cartilage ◽  
Engineer Cartilage

A promising treatment for damaged cartilage is to replace it with tissue-engineered (TE) cartilage. However, the insufficient load-bearing capacity of today’s TE cartilage is an important limiting factor in its clinical application. In native cartilage, collagen fibers resist tension and proteoglycans (PG’s) attract water through osmotic pressure and resist its flow, which allows cartilage to withstand high compressive forces. One of the main challenges for tissue engineering of mechanically stable cartilage is therefore to find the cues to create an engineered tissue with an ultrastructure similar to that of native tissue. Currently, it is possible to tissue engineer cartilage with almost native PG content but collagen reaches only 1/4 of the native content [1]. Furthermore, the specific depth dependent arcade-like organization of collagen in native cartilage (i.e. vertical fibers in the deep zone and horizontal fibers in the superficial zone), which is optimized for distributing loads, has not been addressed in TE’d cartilage. However, the relative importance of matrix component content and collagen network architecture to the mechanical performance of TE cartilage is poorly understood, perhaps because this would require substantial effort on time consuming and labor-intensive experimental studies. The aim of this study is to explore if it is sufficient to produce a tissue with abundant proteoglycans and/or collagen, or whether reproducing the specific arcade-like collagen network in the implant is essential to develop sufficient load-bearing capacity, using a numerical approach.

scholarly journals Determination of the load-bearing capacity of «steel-wood» connections of LVL structures under tension

2021 ◽  
Vol 18 (1) ◽  
pp. 60-69
Author(s):  
Quoc Phong Tran ◽  
Keyword(s):  
Bearing Capacity ◽  
Cross Section ◽  
Steel Plate ◽  
Experimental Studies ◽  
Steel Plates ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Dowel Connections ◽  
Wooden Structures

The article presents the results of calculation of the load-bearing capacity of connections of LVL structures under tension using cylindrical dowels in trusses and frames. The description of calculation schemes for determining the load-bearing capacity of connections with different location and sizes of steel plates in the connection is given. The influence of steel plate placement on the distribution of forces in the cross-section of samples is investigated. Based on the results of analytical and experimental studies, the load-bearing capacity of dowels during bending is considered, as well as the mechanism of wooden structures` fracture during chipping. A comparative analysis of the effectiveness of different schemes of dowel connections with three steel plates under tension is carried out.

scholarly journals Methods of Calculation the Increased Reinforced Concrete Elements by Carrying Capacity of Slope Sections

2021 ◽  
Vol 1203 (2) ◽  
pp. 022051
Author(s):  
Andrii Mazurak ◽  
Roman Kinasz ◽  
Ivan Kovalyk ◽  
Rostyslav Mazurak ◽  
Vitaliy Kalchenko
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Experimental Studies ◽  
Longitudinal Axis ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Theoretical Approaches ◽  
Reinforced Beams ◽  
Eurocode 2 ◽  
Concrete Elements

Abstract Reinforcement bending reinforced concrete structures by increasing the cross section and assessing the load-bearing capacity of the inclined section such elements is an urgent problem, as not yet accumulated adequate research data on the stress-strain state such structures in the span, which works on shear and shear bending moment and transverse force. Analyzing the development theories calculation reinforced concrete elements inclined to the longitudinal axis, we can identify many areas, the main approach of which was based on the calculation using the bases of material resistance, and the use of empirical dependencies. Theoretical approaches calculation the European construction magazine RILEM TC, SNiP 2.03.01.-84* are considered, DBN B.2.6-98 2009 (Eurocode 2), US ACI 318-19. Experimental studies reinforced concrete elements to determine the load-bearing capacity inclined sections were performed on the basis of 5 samples reinforced concrete beams, 14 reinforced samples of reinforced concrete and shotcrete a total of 19 pieces in four series. Beams were made of concrete in each series fck = 19.08 MPa; fck = 27.74 MPa; fck = 20.48 MPa; fck = 20.48 MPa, respectively, reinforced samples with concrete fck = 17.95 MPa; fck = 19.5 MPa (shotcrete fck = 31.00 MPa); shotcrete fck = 19.9 MPa; fck = 19.9 MPa. Also for the manufacture and reinforcement beams used flat and U-shaped frames with working longitudinal reinforcement Ø22, Ø16, Ø12, Ø10, Ø6 A400C, and transverse reinforcement Ø6 A240C (step 120 mm). Reinforcement inclined sections of the experimental beams was performed on one, two or three sides, depending on the variant of the sample and the type of frame flat or U-shaped. Investigations of beams were performed according to the static scheme - a beam on two supports, span L=2100 mm. Deformations of concrete and reinforcement in the samples when determining the bearing capacity of inclined sections were measured using microindicators of the clock type, strain gauges. According to the results theoretical and experimental studies the bearing capacity inclined sections to the longitudinal axis, we can see a significant reassessment between the theoretical values inclined sections according to the new DBN B.2.6.-98: 2009 (Eurocode 2) over the actual results obtained during testing samples 53-67% for conventional beams, and 27-50% for reinforced beams. The results US regulations ACI 318-19 showed convergence of results in the range of 2-9% for samples without reinforcement and 1-7% for samples with reinforcement, but the values show the excess of experimental data over theoretical, indicating the impossibility of accurately determining the actual final bearing capacity. The results the calculation obtained by the method of SNiP 2.03.01-84*, both unreinforced and reinforced beams has a satisfactory agreement with the experimental values in the range of 6-10%.

Experimental Study on Deformation Properties of Lining Structure of Hydraulic Tunnel

2011 ◽  
Vol 105-107 ◽  
pp. 1320-1325
Author(s):  
Shi Lang Xu ◽  
Wei Shen
Keyword(s):  
Bearing Capacity ◽  
Water Pressure ◽  
Interaction Force ◽  
Surrounding Rock ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Water Seepage ◽  
Deformation Properties ◽  
Lining Structure ◽  
Stress And Deformation

A large-scale indoor model test with water pressure is conducted in order to investigate the stress and deformation properties of reinforced concrete lining structures with circular cross-sections. After lining structure cracks, the stress and deformation of reinforcement in lining structures tend to decrease. Although the interaction force between lining structure and surrounding rock increases with the increase of water pressure, but the ratio of interaction force and water pressure decreases, which reveals that the load-bearing capacity of lining structures decreases, and surrounding rock gradually performs as the primary load-bearing body. The internal water pressure carried by lining structure is about 20%~40% of water pressure before cracking and less than 30% after cracking. Test results illustrate that surrounding rock and inner water seepage significantly influence the stress and deformation properties of lining structure, and inner water seepage is the main reason for the reduction of load-bearing capacity of lining structures.

scholarly journals Study on an Innovative Flange Bolted-Welded Connection

2015 ◽  
Vol 9 (1) ◽  
pp. 870-875
Author(s):  
Yufeng Jiao ◽  
Guo Zhao
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Experimental Studies ◽  
High Strength ◽  
Bottom Flange ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Hybrid Joint ◽  
Welded Connection ◽  
Cyclic Loading Tests

This paper proposes a new type of spliced joint, named flange bolted-welded hybrid joint, which is designed to splice I-shape beam to facilitate the construction of industrialized buildings. The flange, welded with the bottom beam flange as well as the web close to bottom flange, are jointed by high strength bolts. Stiffening plate is welded at top of the flange while downhand welding and high strength friction grip bolts are used for the top beam flange and the beam web, respectively. The connection reduces the construction period and costs. In this paper, monotonic and reversed cyclic loading tests were conducted on three full-scale specimens of this innovative joint to investigate its load-bearing capacity, energy-dissipating capacity and failure modes. The results indicate that the joint has high load-bearing capacity and great ductility. The failure mode is due to the slippage of flange bolts as well as the gap development between the two flange plates. The experimental studies enabled improvement of the design of the connection to be used in moment-resisting steel frame structures.

STRENGTH OF CLT PANELS BY SHEAR AND TORSION

2020 ◽  
pp. 315-322
Author(s):  
Andrii Bidakov ◽  
◽  
Oksana Pustovoitova ◽  
Ievgenii Raspopov ◽  
Bogdan Strashko ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Cross Section ◽  
Experimental Studies ◽  
Load Bearing Capacity ◽  
Rolling Shear ◽  
Torsional Strength ◽  
Load Bearing ◽  
Factors Of Influence ◽  
Main Factors ◽  
The Cross

Urgency of the research. Positive experience with the use of CLT panels in distress has been observed for a long time in Eastern Europe and is considered necessary to study the strength and factors affecting the load-bearing capacity of this type of structures made of transverse glued wood (CLT). Target setting. An integral important issue for CLT panels is torsional strength, which has a scheme of destruction by chipping layers of boards and requires the establishment of the main factors of influence to assess the load-bearing capacity of this type of stress. Actual scientific researches and issues analysis. Shear and torsional strength is one of the main issues in the strength of CLT panels as an orthotropic plate, which has interested many researchers from different countries, including Blaß, Görlacher (2002) [1], Bosl (2002) [4], Jeitler (2004) [11 ], Jöbstl, Bogensperger, Schieckhofer [12], Wallner (2004) [18], Bogensperger, Moosbrugger (2007) [3], Silly (2010) [14, 15], Hirschmann (2011), Blaß, Flaig (2012) [2], Dröscher, Brandner, Kreuzinger, Sieder (2013), Dietsch (2017), Serrano (2018). Uninvestigated parts of general matters defining. The issue of identifying factors influencing the bearing capacity of PKD panels during shear and torsion has not been resolved.. The purpose of the article. Establishment of the main factors of influence for an estimation of bearing capacity of CLT of panels at shift and torsion.. The presentation of the main material. Cross laminated timber, as a sheet building material based on layers of boards with mutually perpendicular arrangement of boards in adjacent layers, has a number of important factors that affect the strength of CLT panels in shear and torsion. Thirty years of world experience in the use of CLT panels in multi-storey construction proves the importance of considering different models of panels as diaphragms and rigid frame elements from panel-frame buildings. Particular attention is paid to the nature of the destruction of the panel for chipping, both in the plane of the panel and from the plane. The importance of this type of stress state is further enhanced by a group of different shear or group of test schemes according to EN16351, including rolling shear strength tests. The latter value of strength is a new phenomenological feature of CLT panels. Conclusions and suggestion. Based on experimental studies of the strength of the glued rods in the cross section of CLT panel, the change in strength depending on the diameter of the metal rod and its location in the cross section, which is characterized by alternation of mutually transverse layers of boards.

scholarly journals ACCOUNTING THE STEEL PROFILE IN THE CALCULATIONS OF THE LOADING CAPABILITY OF STEEL-CONCRETE BEAMS

2019 ◽  
pp. 26-33
Author(s):  
N. Vinogradova
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Concrete Beams ◽  
Experimental Studies ◽  
Structural Elements ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
External Reinforcement ◽  
Thin Walled ◽  
Monolithic Structure

Prefabricated monolithic floors are the best solution in terms of cost and time of work. In addition, due to the lightweight filling blocks included in the prefabricated monolithic structure, the overlap has less weight than the classic monolithic or precast slabs. Within the framework of this article, elements of prefabricated monolithic floors — reinforced concrete T-beams with a steel thin-walled profile, which is used primarily as formwork at the stage of construction and installation works, are calculated. Nevertheless, the calculation of the steel profile as an external reinforcement increases the load-bearing capacity of the beams by 50%. To assess the fact effect of the steel thin-walled profile on the strength characteristics of structural elements, experimental studies are conducted. According to the results of the experiment, it is found that the contribution of the steel thin-walled profile to the bearing capacity of the beams is 15%, while if the profile slip due to anchoring in the supporting zones is reduced, the bearing capacity increases by 50-60% compared to similar beams without a profile

Results of Experimental Studies of Piles on Horizontal Loads

2021 ◽  
pp. 48-55
Author(s):  
Махфуд Меразка ◽  
Д. В. Панфилов
Keyword(s):  
Laboratory Experiment ◽  
Bearing Capacity ◽  
Laboratory Tests ◽  
Laboratory Experiments ◽  
Experimental Studies ◽  
Comparative Assessment ◽  
Horizontal Load ◽  
Free Standing ◽  
Load Bearing Capacity ◽  
Load Bearing

Постановка задачи. Рассматриваются и сравниваются результаты лабораторных испытаний горизонтально нагруженной сваи, укрепленной стальной сеткой, расположенной в грунте, и отдельно стоящей сваи без сетки. Результаты. Производится сравнительная оценка перемещений и несущей способности сваи на горизонтальную нагрузку при лабораторном эксперименте. Для сопоставления результатов различных испытаний в лабораторных условиях были выполнены опыты в лотке с песком при одних и тех же диаметре и длине сваи. Эксперименты были проведены на моделях в Центре коллективного пользования им. проф. Ю. М. Борисова г. Воронежа. Выводы. Данные лабораторных экспериментов показали, что применение свай, укрепленных стальной сеткой, позволяет существенно повысить несущую способность свайных фундаментов и снизить горизонтальные и угловые перемещения по сравнению с отдельно стоящими сваями при одной и той же нагрузке. Statement of the problem. The results of laboratory tests of a horizontally loaded pile reinforced with a steel grid located in the ground and a free-standing pile without a grid are considered and compared. Results. A comparative assessment of the load-bearing capacity of the pile for a horizontal load is made during a laboratory experiment. To compare the results of various tests in the laboratory, experiments were performed in a tray with sand at the same diameter and length of the pile. The experiments were carried out on models at the center for collective use named after Prof. Yu. M. Barisov (Voronezh). Conclusions. The data of laboratory experiments have shown that the use of piles reinforced with steel mesh can significantly increase the load-bearing capacity of pile foundations and reduce horizontal movements compared to free-standing piles at the same load.

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