scholarly journals Rheological Effects in the Bridges Constructed with Cantilever Method

2020 ◽  
Vol 9 (1) ◽  
pp. 77-93
Author(s):  
Bartosz Pisarek ◽  
Czesław Machelski
Keyword(s):  
Characteristic Feature ◽  
Cross Section ◽  
Significant Influence ◽  
Bridge Structure ◽  
Concrete Cracking ◽  
Comparative Analyses ◽  
Prestressing Steel ◽  
Geodetic Measurements ◽  
Operation Phase

Abstract A characteristic feature of bridges made using cantilever concreting technology is their excessive deflections, which are a result of rheological processes in concrete and prestressing steel. These deflections can be caused by the destruction of the material, e.g. concrete cracking, as well as the changing of the static scheme of the bridge structure, such as the subsidence of supports. The final result of a structure’s operation is changes in its grade line, which in this paper are considered as the deflection line of a bridge’s span. The purpose of the paper is to determine the participation of a structure’s rotation over supports in the deformation of the span with the largest length. The authors proposed an algorithm for determining the deflection function and rotation angles, which were obtained on the basis of changes in the curvature of the beam. It is characterised by an accurate mapping of the rheological processes that occur in the bridge, which is calculated on the basis of the changes of the grade line obtained from geodetic measurements on site. The paper proposes a general geometric indicator of the box cross-section cantilever, which is calculated for the construction phase, and a different indicator for the operation phase. They can be used for comparative analyses of various bridges. The analysis of deflections in cantilever bridges during the operation phase of their longest spans indicates that there is a significant influence of the angles of rotation over the supports. In the paper, such a group of bridges is qualified as unstable, in which the static scheme changes from a determinate cantilever state (the construction phase) into a multi-span system with different span lengths (the operation phase).

scholarly journals Estimation of Rheological Effects in Cantilever Concrete Bridges on the Basis of a Span's Deflection Line

2021 ◽  
Author(s):  
Bartosz Pisarek ◽  
Czeslaw Machelski
Keyword(s):  
Characteristic Feature ◽  
Marked Improvement ◽  
Small Extent ◽  
Concrete Bridges ◽  
Bridge Structure ◽  
Concrete Cracking ◽  
Measurement Results ◽  
Bridge Structures ◽  
Original Measurement ◽  
Internal Forces

A characteristic feature of bridges as large span objects made using cantilever concreting technology are their excessive deflections, which are a result of rheological processes in concrete and pre-stressing steel. These deflections can be caused by the destruction of the material, e.g., concrete cracking, as well as the changing of the static scheme of the bridge structure, such as the subsidence of supports. The purpose of the work is to determine internal forces based on the deformation of a span. An algorithm for the correction of the deflection function, which is determined from geodetic measurements with a low accuracy, was proposed. It is characterized by a marked improvement in the results of calculations and, to a small extent, leads to the smoothing of the original measurement results. The algorithm is adapted to the analysis of a selected fragment of the structure, e.g., spans with the largest length and can be useful for monitoring bridge structures.

scholarly journals Formal Functions of Metric Dissonance in Rock Music

2014 ◽  
Vol 20 (2) ◽  
Author(s):  
Nicole Biamonte
Keyword(s):  
Cross Section ◽  
Rock Music ◽  
Phrase Structure ◽  
Comparative Analyses ◽  
Metric Dissonance ◽  
Corpus Studies ◽  
History Of

This article explores the interactions of metric dissonance with phrase structure and form in rock music, offers categorization schemes for common formal functions of metric dissonance, and presents several corpus studies of metric dissonance in the works of single artists and bands as well as in a cross-section of rock songs. These data allow for comparative analyses of the metric profile of a given artist or band, suggest genre correlations with particular metric patterns, and demonstrate a trend of increasing metric dissonance throughout the history of rock.

scholarly journals Assessing the Instantaneous Stiffness of Cracked Reinforced Concrete Beams Based on a Gradual Change in Strain Distributions

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Chunyu Fu ◽  
Dawei Tong ◽  
Yuyang Wang
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Cross Section ◽  
Concrete Beams ◽  
Internal Force ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Gradual Change ◽  
Concrete Cracking ◽  
Good Agreement

Concrete cracking causes a gradual change in strain distributions along the cross section height of reinforced concrete beams, which will finally affect their instantaneous stiffness. A method for assessing the stiffness is proposed based on the gradual change, which is considered through modeling different strain distributions for key sections in cracked regions. Internal force equilibria are adopted to find a solution to top strains and neutral axes in the models, and then the inertias of the key sections are calculated to assess the beam stiffness. The proposed method has been validated using experimental results obtained from tests on five reinforced concrete beams. The predicted stiffness and displacements are shown to provide a good agreement with experimental data. The instantaneous stiffness is proven to greatly depend on the crack number and depth. This dependence can be exactly reflected by the proposed method through simulating the gradual change in concrete strain distributions.

Microscopic Evaluation of Commingling-Hybrid Yarns

2007 ◽  
Vol 539-543 ◽  
pp. 992-996 ◽  
Author(s):  
Bok Choon Kang ◽  
K.H. Min ◽  
Y.H. Lee ◽  
Beong Bok Hwang ◽  
Chathura Nalendra Herath
Keyword(s):  
Mechanical Properties ◽  
Characteristic Feature ◽  
Cross Section ◽  
Process Parameters ◽  
Volume Content ◽  
Light Weight ◽  
Textile Fibers ◽  
Hybrid Yarn ◽  
Microscopic Evaluation ◽  
End Products

Fibers made of elements such as carbon, aramid and glass have higher mechanical properties than other conventional textile fibers and they enable the production of light weight composites as end products. Furthermore, commingling hybrid yarns generally have a characteristic feature so that their components are distributed homogeneously enough over the yarn cross section. A normal air texturerising machine was modified to produce commingling hybrid yarns for test samples. Different process parameters were applied to produce the hybridized yarn samples. However, these process parameters turned out to have little effect on the filament distribution over the hybrid yarn cross section in terms of homogeneity. The analysis in this paper is focused on the pattern of mixing of filaments over a cross section of hybrid yarns according to different combinations of reinforcement and matrix filament yarns through microscopic view. The volume content of filament in hybrid yarn cross section was maintained at 50% for both reinforced and matrix, and the hybrid yarns count at 600 tex throughout experiments. It was concluded from the experiments that the diameters of reinforcement and matrix filaments have strong effects on the pattern of mixing of filaments over a cross section of hybrid yarns such that the hybrid yarns with more or less equal diameters of reinforcement and matrix filaments showed considerably even distributions over the hybrid yarn cross section.

Influence of the Steel Channel Shaped Shear Connectors on the Stability of the Simply Supported Steel Bridge without the Intermediate Bracing System in the Construction Stage

2021 ◽  
Vol 879 ◽  
pp. 151-168
Author(s):  
Van Khai Nguyen ◽  
Nghia Dai Van ◽  
Van Tuong Khanh Vo ◽  
Rin Anh Nguyen ◽  
Phuc Gia Nguyen ◽  
...  
Keyword(s):  
Cross Section ◽  
Steel Plate ◽  
Moment Of Inertia ◽  
Steel Bridge ◽  
Bridge Structure ◽  
Shear Connectors ◽  
The Cross ◽  
The Stability ◽  
The Moment ◽  
Main Girder

Steel bridge structure without intermediate bracing system (IBS) has been widely used in several countries and one of them is Japan. In this type of structure, the main steel girder is not reinforced by the stiffeners. The stiffness of the main girder is enhanced with steel plate directly welded to the top flange of the main girder, forming the “beams–system”. The reinforced concrete deck slab with the set of main girder and steel plate works compositely through steel shear connectors whose shape is C (channel) or I character. As for steel bridge structures, the main role of shear connectors is shear resistance between the concrete deck slab and steel girder plate in the exploitation stage. However, previous research has shown that the density of shear connectors influences on the stability as well as the stiffness of the bridge structure. Therefore, it has approved that this appurtenance is able to not only have the ability of shear resistance but also enhance the stiffness of the steel bridge structure which is particularly surveyed with the type of especial bridge structure – the steel bridge structure without IBS. Hence, the shear connectors in this kind of bridge structure are deliberately researched as an extra role in the construction stage. The following factors of the channel shape shear connectors would be researched for evaluating their impacting level on the stability of the special steel bridge structure: the properties (the length and the moment of inertia of the cross-section) and the density on the steel plate. Through the analysis of impacting level to the stability of three mentioned factors (the length and density of the shear connectors; the moment of inertia of the cross-section), the expected result is as following: 1) The minimum density of shear connectors is proposed. 2) The influence of the moment of inertia of the cross-section, the density, and the length on the stability is quite clear. 3) As for the economy, the optimal designed range among three factors is also suggested.

Yielding of Asparagus Depending on Harvest Ending Date

2010 ◽  
Vol 73 (1) ◽  
pp. 67-75
Author(s):  
Mikołaj Knaflewski ◽  
Włodzimierz Krzesiński ◽  
Monika Gąsecka ◽  
Jerzy Stachowiak
Keyword(s):  
Field Experiment ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Cross Section ◽  
Significant Influence ◽  
Light Absorption ◽  
Harvest Time ◽  
Storage Roots ◽  
Area Index

Yielding of Asparagus Depending on Harvest Ending DateThe field experiment focused on the determination of yielding of asparagus cv. ‘Thielim’ in relation to harvest duration: traditional (until June 20th), shortened (June 10th) and prolonged (30thJune) harvests. The variation in harvest ending dates did not have a significant influence on the total, marketable and non-marketable yields as well as on the crown weight and the number of storage roots. However, the extension of harvest time until June 30thresulted in an increase in the number of spears in the total and marketable yields, accompanied by a decrease in their diameter. Also prolonging harvest affected negatively the summer stalk size. During harvest until June 10thasparagus plants probably did not use their full yielding potential, because of too short harvest time. It resulted in increased height, weight, light absorption of summer stalks, leaf area index (LAI) and the total of cross-section areas of summer stalks (PPPA) with no significant differences in yield.

scholarly journals Evaluation of Grape Pomace Composting Process

2014 ◽  
Vol 62 (5) ◽  
pp. 875-881 ◽  
Author(s):  
Patrik Burg ◽  
Tomáš Vítěz ◽  
Jan Turan ◽  
Jana Burgová
Keyword(s):  
Moisture Content ◽  
Bulk Density ◽  
Cross Section ◽  
Significant Influence ◽  
Grape Pomace ◽  
Wood Chips ◽  
Waste Wood ◽  
Composting Process ◽  
The Individual

The paper deals with the problems of composting of grape pomace in strip compost piles. The three variants of compost piles formed from grape pomace and vegetables waste, wood chips and mature in varying proportions were tested. Turning of piles was performed using windrow turner PKS 2.8, in which the achieved performance was monitored. On the performance of windrow turner has a significant influence also cross section or width and height of turning piles and the bulk density of ingredients including their moisture. In evaluating, attention has been paid to assessment of selected parameters (temperature, moisture content) of the composting process. From the viewpoint of temperature course, the highest temperature reached at the piles in Var. I (64.1 °C) and Var. II (55.3 °C). Moisture of compost piles in the individual variants did not differ significantly and ranged between 25–35%.

scholarly journals Analisis Perbandingan Kehilangan Prategang Akibat Variasi Letak Tendon PC I Girder Jembatan Beton Prategang

2020 ◽  
Vol 2 (2) ◽  
pp. 034-042
Author(s):  
Ibham Yamin ◽  
Siswanti Zuraida ◽  
Ilham Ilham
Keyword(s):  
Cross Section ◽  
Prestressed Concrete ◽  
Neutral Axis ◽  
Bridge Structure ◽  
Allowable Stress ◽  
Final Project ◽  
Number Of Factors ◽  
Parabolic Shape ◽  
Prestressed Concrete Bridge ◽  
Over Time

Prestressed force loss always occurs in prestressed concrete (loss prestressed). The most common form used in pre-tensile beams is straight tendons and for post-tensile beams are curved tendons. In planning a prestressed concrete bridge structure, the loss of prestressed force must be considered, because the stress on the prestressed concrete tendon decreases continuously over time. The number of factors that are interrelated, for the effectiveness of the design, location of tendons along the spans need to be considered, so that the tensile strength that occurs in the extreme fiber beam is limited or none at all in the cross section. This final project will examine the shape of the PC beam I Girder with 4 tendon setting conditions namely straight tendon cable which is on the neutral axis so that the eccentricity = 0 (condition1), straight tendon cable which is at 1/6 h so that the eccentricity ≠ 0 (condition 2), tendon cable with draped / parabolic shape (condition 3), and tendon condition with harped shape (condition 4). The biggest prestressed loss results were PC I Girder (condition 2) = 395.81 MPa (26.07%), while the smallest prestressed loss is PC I Girder (condition3) = 367.44 MPa (24.2%). Condition 1 and 2 in girder is not suitable for use because it exceeds the value of the allowable stress at the limit of prestressed and deflection permits on girder are safe for each condition.

The investigation of basic microfluidic elements in LTCC structures

2018 ◽  
Vol 35 (3) ◽  
pp. 133-138
Author(s):  
Darko Belavic ◽  
Andraž Bradeško ◽  
Hana Uršič
Keyword(s):  
Cross Section ◽  
Significant Influence ◽  
Research Work ◽  
Applied Pressure ◽  
Microfluidic Devices ◽  
Polymer Materials ◽  
Hydrodynamic Resistance ◽  
Content Type ◽  
Micro Channels ◽  
Fluid Properties

Purpose The purpose of this study is to design, fabricate and investigate low-temperature co-fired ceramic (LTCC) structures with integrated microfluidic elements. Special attention is paid to the study of fluid properties of micro-channels and microvalves, which are important constitutive parts of both, microfluidic systems and individual microfluidic devices. Design/methodology/approach Several test patterns of fluid channels with different geometry and different types of valves were designed and realized in LTCC technology. All test structures were tested under the flow of two fluids (liquids): water and isopropyl alcohol. Flow rates at different applied pressure were measured and hydrodynamic resistance and diode effect were calculated. Findings The investigation of the channels showed that viscosity of fluidic media has significant influence on the hydrodynamic resistance in channels with rectangular cross-section, while this effect is small on channels with square cross-section. The viscosity also has a decisive influence on the diode effect of different shape of valves, and therefore, it is important in the selection of the valve in practical applications. Research limitations/implications In this work, the investigation of hydrodynamic resistance of channels and diode effect of passive valves is limited on selected geometry and only on two fluidic media and two applied pressures. All these and some other parameters have a significant influence on fluidic properties, but this will be the topic of the next research work, which will be supported by numerical modelling. Practical implications The presented results are useful in the future designing process of LTCC-based microfluidic devices and systems. Originality/value Microfluidic in the LTCC structures is an unconventional use of this technology. Therefore, the fluid properties are relatively unsearched. On the other hand, the global use of microfluidic devices and systems is growing rapidly in various applications. They are mostly made by polymer materials, however, in more demanding applications; ceramic is a useful alternative.

PHOTODETACHMENT ofH- NEAR A SOFT WALL

2007 ◽  
Vol 06 (02) ◽  
pp. 353-362 ◽  
Author(s):  
GUANGCAN YANG ◽  
YIZHUANG ZHENG ◽  
XIANXING CHI
Keyword(s):  
Cross Section ◽  
Significant Influence ◽  
Analytical Formula ◽  
Electronic Energy ◽  
Sinusoidal Oscillation ◽  
Soft Wall ◽  
The Cross

We investigate the photodetachment of H - near an inelastic interface semiclassically. It is found that the inelasticity of an interface has significant influence on the photodetachment process. We have derived an analytical formula of the cross section of photodetachment. The spectrum of photodetachment consists of a smooth background and a sinusoidal oscillation whose frequency depends on the electronic energy, the reflection of the wall and the distance between the ion and the wall.

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