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 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 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%.

Assessment of the Load-Bearing Capacity of Bark-Included Junctions in Crataegus monogyna Jacq. in the Presence and Absence of Natural Braces

2020 ◽  
Vol 46 (3) ◽  
pp. 210-227
Author(s):  
Dean Meadows ◽  
Duncan Slater
Keyword(s):  
Bearing Capacity ◽  
Mechanical Performance ◽  
Mechanical Resistance ◽  
Single Specimen ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Crataegus Monogyna ◽  
Naturally Occurring ◽  
Mode Of Failure ◽  
Control Branch

Bark-included junctions are frequently encountered defects within the aerial structures of trees. The presence of included bark within a branch junction can substantially reduce the junction’s factor of safety. Recent research has found naturally occurring bracing to be a primary cause of the formation of included bark within branch junctions. This study tested the load-bearing capacity of branch junctions in hawthorn (Crataegus monogyna Jacq.) using rupture tests and compared the mechanical performance of “control” branch junctions, bark-included junctions with the natural bracing retained, and bark-included junctions where we had intentionally removed their natural braces by cutting them out. Substantial variability was observed in the failure kinematics of bark-included branch junctions when their natural braces were retained. The type of natural brace present affected the mode of failure of the branch junctions when pulled apart. A single specimen with fused branches presented the strongest form of natural brace in this study, followed by entwining branches, whereas crossing branches were found to provide the least mechanical resistance. This study provides initial evidence that the type of associated natural brace is an important consideration when an arborist is trying to assess the likely mechanical performance of a bark-included junction within a tree and its likelihood of failure.

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

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.

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.

scholarly journals Length Effect on Load Bearing Capacities of Friction Rock Bolts

2019 ◽  
Author(s):  
Eren Komurlu ◽  
Serhat Demir
Keyword(s):  
Numerical Modelling ◽  
Bearing Capacity ◽  
Experimental Studies ◽  
Rock Bolt ◽  
Rock Bolts ◽  
Length Effect ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Pull Out ◽  
Modelling Study

Change in the load bearing capacity of the split set type friction rock bolts with variations of bolt lengths was investigated within this study. To determine a relation between the load bearing capacity and bolt length parameters, different friction bolt models with various lengths were analyzed with a numerical modelling study. In addition, a series of pull-out tests was carried out to evaluate the load bearing capacities of the split set type friction rock bolts with different lengths. The load bearing capacity of the bolts was found to decreasingly increase with the increase in the bolt length. As an outcome of this study, a relation between the load bearing capacity and rock bolt length parameters is suggested in accordance with the results obtained from both numerical and experimental studies.

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