scholarly journals Effect of Hollow Shape on the Behavior of Reinforced Self-Compacting Concrete Slender Column Under Eccentric Loading

2021 ◽  
Vol 39 (6) ◽  
pp. 884-892
Author(s):  
Maha G. Ghaddar
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Great Influence ◽  
Axial Loading ◽  
Test Results ◽  
Compression Load ◽  
Large Eccentricity ◽  
Different Shapes ◽  
Slender Columns ◽  
Slender Column

Results of testing reinforced self-compacted concrete slender columns having longitudinal holes concealing PVC pipe in their cross sections under axial compression load and uniaxial bending are presented in this paper. The effect of hollow shape on the performance of slender columns having 200x200mm quadratic cross section and 1300mm long under concentric and eccentric loads was investigated. Three different shapes of central hole: circular, square, and lozenge pattern in addition to the different load eccentricity values were considered to investigate the axial loading resistance and cracking load, lateral and longitudinal deflections of the columns. Test results have showed that altering the hollow shape inside the area of column cross section does not show a great influence on the column behavior unless the hollow ratio changed. The effect of hole shape or the hollow ratio on loading capacity is insignificant but the existence of a hole embedded longitudinally in the column significantly decreases its ultimate capacity. The effect of hollow shape or hollow ratio on a slender columns behavior subjected to eccentric loading with small ratio of load eccentricity to total column thickness (e/h=.33) was more than that of large eccentricity (e/h=1.0). Accordingly, the decrease in loading column capacity of columns was (5.0%, 2.5%, and 6.6%) compared to (3.2%, 2.2%, and 4.7%) for the same hole shapes respectively.

scholarly journals Effect of Hollowing Ratio on the Behavior of Hollow Self-Compacting Reinforced Concrete Slender Column Under Eccentric Loading

2018 ◽  
Vol 7 (4.20) ◽  
pp. 390 ◽  
Author(s):  
Ihsan A. S. Al- Shaarbaf ◽  
Mohammed J. H. Al-zubaidi ◽  
Emad A. A. Al- Zaidy
Keyword(s):  
Reinforced Concrete ◽  
Load Capacity ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Small Eccentricity ◽  
Compression Load ◽  
Load Carrying ◽  
Different Diameters ◽  
Slender Columns ◽  
Slender Column

In this research the behavior of reinforced concrete slender columns with longitudinal hole under axial compression load and uniaxial bending is investigated. The paper includes testing of ten slender columns with dimensions (150 150 1300 mm). The investigation deals with the effect of using different diameters of  column hole on the values of the load carrying capacity and cracking loads, mid-height lateral deflection and longitudinal shortening of the columns. Five diameters for the column holes were considered (0, 25.4, 38.1, 50.8,  and 76.2)mm. Test results have showed that when the holes were located at the center of the column cross-section and the column was loaded with high load eccentricity, the effect of hollowing ratio on load capacity is insignificant. For hollowing ratios used in this study (0%, 2.3% ,5.1%, 9% and 20.3%), the ultimate load is decreased by (0%, 0.28%, 1.03%, 3.28% and 6.48%) respectively. The effect of hollowing ratio on columns  loaded with small eccentricity of 50mm (e/h=.33)  is greater than the effect of hollow ratio of columns with 150 mm eccentricity(e/h=1.0) which reduces the load capacity  for the columns by (0.00%, 0.66%, 2.65%, 4.97% and 11.26%) for hollowing ratios (0%, 2.3%, 5.1%, 9% and 20.3%) respectively.  

scholarly journals Confinement effects for rubberised concrete in tubular steel cross-sections under combined loading

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
A. Mujdeci ◽  
D. V. Bompa ◽  
A. Y. Elghazouli
Keyword(s):  
Axial Compression ◽  
Cross Section ◽  
Cross Sections ◽  
Image Correlation ◽  
Combined Loading ◽  
Test Results ◽  
Compression Tests ◽  
Confinement Effects ◽  
Rubber Content ◽  
Dependent Modification

AbstractThis paper describes an experimental investigation into confinement effects provided by circular tubular sections to rubberised concrete materials under combined loading. The tests include specimens with 0%, 30% and 60% rubber replacement of mineral aggregates by volume. After describing the experimental arrangements and specimen details, the results of bending and eccentric compression tests are presented, together with complementary axial compression tests on stub-column samples. Tests on hollow steel specimens are also included for comparison purposes. Particular focus is given to assessing the confinement effects in the infill concrete as well as their influence on the axial–bending cross-section strength interaction. The results show that whilst the capacity is reduced with the increase in the rubber replacement ratio, an enhanced confinement action is obtained for high rubber content concrete compared with conventional materials. Test measurements by means of digital image correlation techniques show that the confinement in axial compression and the neutral axis position under combined loading depend on the rubber content. Analytical procedures for determining the capacity of rubberised concrete infilled cross-sections are also considered based on the test results as well as those from a collated database and then compared with available recommendations. Rubber content-dependent modification factors are proposed to provide more realistic representations of the axial and flexural cross-section capacities. The test results and observations are used, in conjunction with a number of analytical assessments, to highlight the main parameters influencing the behaviour and to propose simplified expressions for determining the cross-section strength under combined compression and bending.

Axial Loading of Annular Bonded Rubber Blocks

2003 ◽  
Vol 76 (5) ◽  
pp. 1194-1211 ◽  
Author(s):  
J. M. Horton ◽  
G. E. Tupholme ◽  
M. J. C. Gover
Keyword(s):  
Experimental Data ◽  
Stress Distribution ◽  
Closed Form ◽  
Cross Section ◽  
Classical Theory ◽  
Cross Sections ◽  
Axial Loading ◽  
Theory Of Elasticity ◽  
Governing Equations ◽  
Annular Cross Section

Abstract Closed-form expressions are derived using a superposition approach for the axial deflection and stress distribution of axially loaded rubber blocks of annular cross-section, whose ends are bonded to rigid plates. These satisfy exactly the governing equations and conditions based upon the classical theory of elasticity. Readily calculable relationships are derived for the corresponding apparent Young's modulus, Ea, and the modified modulus, Ea′, and their numerical values are compared with the available experimental data. Elementary expressions for evaluating Ea and Ea′ approximately are deduced from these, in forms which are closely analogous to those given previously for blocks of circular and long, thin rectangular cross-sections. The profiles of the deformed lateral surfaces of the block are discussed and it is confirmed that the assumption of parabolic lateral profiles is not valid generally.

Experimental study on improvement effect of guide wall to water flow in bend of spillway chute

2015 ◽  
Vol 73 (3) ◽  
pp. 669-678 ◽  
Author(s):  
Qinghua Zhang ◽  
Yanfang Diao ◽  
Xingtao Zhai ◽  
Shuning Li
Keyword(s):  
Water Flow ◽  
Cross Section ◽  
Cross Sections ◽  
Water Surface ◽  
Great Influence ◽  
Flow Rates ◽  
Improvement Effect ◽  
Guide Wall ◽  
The Cross ◽  
Surface Improvement

In order to improve water flow in a bend of a spillway chute using a guide wall, modeling experiments with or without a guide wall under conditions of three different bend axial radii, three chute bottom slopes and three flow rates were carried out in this study. Two indexes were calculated, which are the improved water surface uniformity and the reduced rate of water surface difference in concave and convex banks of the cross-section. The results show that: (1) setting a guide wall in a bend can improve water flow in the bend because it increased the water surface uniformity of the cross-section and reduced the water surface difference in the concave and convex banks; (2) the smaller the bend axial radius, the better the water surface improvement effect will be using a guide wall; (3) the steeper the bottom slope, the more cross-sections with less water surface difference; and (4) flow rates have a great influence on water surface improvement in the bend, and the guide wall can improve water flow obviously when the water depth in the starting section of the bend is lower than the height of the guide wall. This study has important implications in engineering design of guide walls.

scholarly journals Cross hole sonic test results for analysis of pile load test

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Swapan Kunar Bagui ◽  
S. K. Puri ◽  
K. Subbiah
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Wide Band ◽  
Load Test ◽  
Test Results ◽  
Pile Capacity ◽  
Uniform Cross Section ◽  
Cell Test ◽  
Pile Load Test ◽  
Sonic Logging

AbstractQuality of concrete for pile can be checked using Cross-hole Sonic Logging (CSL) Test. A processing method wide-band CSL data is presented herein. First Time Arrival (FTA) is an important consideration. In pile capacity analysis or CSL analysis, it is assumed that pile cross section is uniform with uniform value of elastic modulus of concrete but in real practice both are non-uniform. The procedure identifies the location accuracy and further characterizes the features of the defect. FTA is used to find out the location of the distress in the pile. This method identifies the exact location of any void or defect inside the rebar cage of a drilled shaft. This method provides a significant improvement to current techniques used in quality control during construction of bridges. In this present paper, the analysis has been carried out based on uniform and non-uniform values of pile cross section and E value of concrete. Cross hole sonic and pile load test using O-Cell were carried out on same pile at 7 and 28 days of concreting. Same pipes were used for base grout after cross hole sonic test. These results were used to analyze O-cell test results based on a case study and presented in this paper. The distribution of skin frication and skin friction force has also been presented herein with both uniform and non-uniform cross section and E values of concrete. Based on the field test results and analysis a simplified methodology, has been proposed in this paper, for development of Equivalent Top Down Loading with consideration of elastic shortening of pile and surrounding soil for both cases i.e., uniform and non-uniform E values and pile cross sections.

scholarly journals Behavior of reinforced concrete slender rectangular columns under uniaxial loading

2018 ◽  
Vol 162 ◽  
pp. 04022
Author(s):  
Bassman Muhammad
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Strength ◽  
Cross Section ◽  
Bending Moment ◽  
The Past ◽  
Slender Columns ◽  
Slender Column ◽  
Structural Engineers ◽  
Rectangular Columns

Two proposed formulae are presented to obtain the reinforced concrete slender column capacity. Reinforced concrete slender columns are used more nowadays than in the past 30 years because of development of engineering materials. Structural engineers that adopted the ACI 318M Code know that the design of this type of columns is more tedious than short ones. This research proposes two formulae that reflect the ultimate strength of cross section of slender columns, one for the axial and the second for the bending moment. Case study of 656250 columns is generated to cover most variable properties of columns, analyzed using MATLAB (R2017a) Program to obtain the ultimate strength of cross section then compared to the strength of slender columns.

scholarly journals Numerical Simulation of Pervious Concrete Based on Random Pore Model

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Jingsong Shan ◽  
Jinle He ◽  
Feng Li
Keyword(s):  
Simulation Model ◽  
Cement Paste ◽  
Cross Sections ◽  
Great Influence ◽  
Element Model ◽  
Pervious Concrete ◽  
Test Results ◽  
Composite Modulus ◽  
The Monte Carlo Method ◽  
Inclined Angle

The features of the pores in pervious concrete have a great influence on the mechanical property of the pervious concrete. In this study, a finite element model (FEM) with random pores has been used to simulate the mechanical characteristics of pervious concrete. First, pervious concrete specimens with two different porosities were prepared in the laboratory. Then, the specimens were cut and the pores features were extracted based on the images of cross-sections. Thereafter, the ellipse and roundness were introduced into a simulation model to describe the characteristics of pores including the size, area, shape, and inclined angle which have been developed randomly in the FEM using the Monte Carlo method. In the simulation model, the aggregate and cement paste have been simplified into a composite material, and the method of determining the composite modulus of aggregate-cement paste is discussed. The simulation results show that the shape and distribution of the pores have an obvious influence on the internal stress of the pervious concrete and the pore features can be considered reasonable for the validity of the simulations. In addition, the composite modulus of the aggregate-cement paste can be determined by comparing the simulation and test results. The recommended composite modulus in the pervious concrete simulation model is much lower than that of common impervious concrete.

Electron Irradiation Effects in Polyoxymethylene Crystals Grown Inside Trioxane Crystals

1971 ◽  
Vol 29 ◽  
pp. 78-79
Author(s):  
J. P. Colson ◽  
D. H. Reneker
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Detailed Examination ◽  
The Other ◽  
Electron Micrograph ◽  
Irradiation Effects ◽  
Threefold Axis ◽  
Typical Sample ◽  
Polymer Crystals ◽  
Chain Axis

Polyoxymethylene (POM) crystals grow inside trioxane crystals which have been irradiated and heated to a temperature slightly below their melting point. Figure 1 shows a low magnification electron micrograph of a group of such POM crystals. Detailed examination at higher magnification showed that three distinct types of POM crystals grew in a typical sample. The three types of POM crystals were distinguished by the direction that the polymer chain axis in each crystal made with respect to the threefold axis of the trioxane crystal. These polyoxymethylene crystals were described previously.At low magnifications the three types of polymer crystals appeared as slender rods. One type had a hexagonal cross section and the other two types had rectangular cross sections, that is, they were ribbonlike.

A quantitative approach to inner shell losses

1978 ◽  
Vol 36 (1) ◽  
pp. 526-527 ◽  
Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers
Keyword(s):  
Energy Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Background Intensity ◽  
Core Excitation ◽  
Quantitative Basis ◽  
Cross Section Differential ◽  
Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

Oxygen K near edge structures studied with multiple scattering calculations

1988 ◽  
Vol 46 ◽  
pp. 504-505
Author(s):  
Xudong Weng ◽  
Peter Rez
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Partial Cross Section ◽  
Energy Window ◽  
Edge Structure ◽  
Fine Structures ◽  
Hydrogenic Model ◽  
Electron Energy Loss ◽  
Quantitative Chemical

In electron energy loss spectroscopy, quantitative chemical microanalysis is performed by comparison of the intensity under a specific inner shell edge with the corresponding partial cross section. There are two commonly used models for calculations of atomic partial cross sections, the hydrogenic model and the Hartree-Slater model. Partial cross sections could also be measured from standards of known compositions. These partial cross sections are complicated by variations in the edge shapes, such as the near edge structure (ELNES) and extended fine structures (ELEXFS). The role of these solid state effects in the partial cross sections, and the transferability of the partial cross sections from material to material, has yet to be fully explored. In this work, we consider the oxygen K edge in several oxides as oxygen is present in many materials. Since the energy window of interest is in the range of 20-100 eV, we limit ourselves to the near edge structures.

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