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.

scholarly journals Anisotropy of a Selective Laser-Melted Ti–6Al–4V Lattice Structure

2021 ◽  
Author(s):  
Dingye YAO ◽  
Weixing ZHOU ◽  
Yuli MA ◽  
Bo He
Keyword(s):  
Mechanical Properties ◽  
Cross Section ◽  
Cross Sections ◽  
Lattice Structure ◽  
Physical Models ◽  
Image Correlation ◽  
Isotropic Hardening ◽  
Lattice Structures ◽  
Compression Tests ◽  
Small Cross Section

Abstract Selective laser melting (SLM) is a widely adopted additive manufacturing process for the preparation of metallic lattice structures. However, it causes a build-direction-dependent anisotropy of morphologies, microstructures, and mechanical properties, making it difficult to predict the behavior and performance of lattice structures. In this study, tensile samples with different cross-sections and build directions (BDs) were fabricated by SLM. The anisotropic morphology, microstructure, and tensile properties were observed and measured using optical microscopy, scanning electron microscopy, and three-dimensional digital image correlation to determine the effects of the size and BD of SLMed materials. The extracted data were sequentially used to modify the geometric and physical models of the lattice. Body-centered cubic lattice structures were fabricated by SLM, and compression tests were performed to verify the modified compression model. In addition to the BD-related grains, the cross-sectional area of the SLMed sample affects its mechanical properties. The small cross-section makes the microstructure finer because the proportion of the contour path that uses higher power is no longer negligible. The sample with small cross-section has more anisotropy because of the lack of tolerance to heterogeneity and macro defects like roughness. In this study, by analyzing samples with small cross-sections, a model consisting of an isotropic hardening law and Hill’s anisotropic yield function is established to describe the yield and plasticity behavior of the as-built SLMed Ti–6Al–4V lattice. The simulated and experimental data fit very well, verifying the methodology employed in this study.

scholarly journals Study on the Mechanical Properties of BFRP Tube Confined Concrete Short Columns under Axial Compression

2020 ◽  
Author(s):  
Xindong Ding ◽  
Shuqing Wang ◽  
Yu Liu ◽  
Zepeng Zheng
Keyword(s):  
Axial Compression ◽  
Brittle Failure ◽  
Failure Modes ◽  
Concrete Strength ◽  
Steel Tube ◽  
Confined Concrete ◽  
Test Results ◽  
Compression Tests ◽  
Short Columns ◽  
Square Steel Tube

Axial compression tests were carried out on 6 square steel tube confined concrete short columns and 6 BFRP square pipe confined concrete axial compression tests. The concrete strength grades were C30, C40, and C50. The test results show that the failure modes of steel pipe and BFRP pipe are obviously different, and the BFRP pipe undergoes brittle failure. Compared with the short columns of concrete confined by BFRP pipes, the ultimate bearing capacity of axial compression is increased by -76.46%, -76.01%, and -73.06%, and the ultimate displacements are -79.20%, -80.78%, -71.71%.

scholarly journals Comparison between resistant load contours generated considering the parabolic-rectangular (DPR) and the rectangular (DR) stress-strain diagrams for rectangular sections under combined axial compression and biaxial bending

2018 ◽  
Vol 11 (3) ◽  
pp. 455-473
Author(s):  
Y. F. FONSECA ◽  
A. S. C. SILVA
Keyword(s):  
Axial Compression ◽  
Cross Section ◽  
Cross Sections ◽  
Strength Class ◽  
Concrete Strength ◽  
Strain Diagram ◽  
Biaxial Bending ◽  
Stress Strain ◽  
Oblique Loading ◽  
Stress Diagram

Abstract The aim of this study is to compare the load contour diagrams generated for rectangular RC cross-sections under combined axial compression and biaxial bending obtained by the two forms of analysis allowed by NBR 6118:2014 [1]: the first using the parabolic-rectangular stress-strain diagram (DPR) and the second using the rectangular (constant stress) diagram (DR). In order to compare the load contours generated, a reference cross-section was adopted for which the concrete strength class (from C20 to C90) and the deformation domains (4, 4a and 5) were varied for the study. It was studied whether the use of the different diagrams (DPR or DR) would provide greater (or smaller) resistant efforts for the same section. The results show that the use of the DR is only acceptable when the section is working up to the 4th domain. Above this domain, it was observed that the use of this diagram shows resistant efforts inferior to those calculated by the DPR. In addition, it was found that, for concretes with resistance class above C50, in oblique loading directions, the use of the DR presents higher resistant efforts than those calculated using the DPR.

Concrete-Filled Hollow Structural Sections. II: Flexural Members, Beam-Columns, Tension, and Shear

2021 ◽  
Author(s):  
Kyle Tousignant ◽  
Jeffrey Packer
Keyword(s):  
Reliability Analysis ◽  
Axial Compression ◽  
Cross Section ◽  
North American ◽  
Combined Loading ◽  
Flexural Members ◽  
Beam Columns ◽  
First Order ◽  
Hollow Structural Section ◽  
Hollow Structural Sections

This article reviews contemporary North American and international approaches to the design of concrete-filled hollow structural section (HSS) members for flexure, axial compression plus uniaxial bending, tension, and shear. Results from tests on concrete-filled HSS members under flexure and combined loading are compared to predicted strengths using current (CSA S16:19 and AISC 360-16) and recommended CSA S16 design equations (with limits of validity). A first-order reliability analysis of design provisions for flexure is performed in accordance with CSA S408-11, and recommendations are made for potential revision of CSA S16. Design examples are provided, and results are compared to the counterpart American code (AISC 360-16). This paper is Part II of a two-part series. Part I covers materials, cross-section classification, and concentrically loaded columns.

Strength Attenuation Law of Damaged Rock Samples and its Structure Effect

2013 ◽  
Vol 353-356 ◽  
pp. 602-607
Author(s):  
Hai Jian Su ◽  
Hong Wen Jing ◽  
Chen Wang ◽  
Bo Meng
Keyword(s):  
Uniaxial Compression ◽  
Axial Compression ◽  
Confining Pressure ◽  
Structure Effect ◽  
Thick Wall ◽  
Test Results ◽  
Compression Tests ◽  
Rock Samples ◽  
Nonlinear Fitting ◽  
Attenuation Value

In order to study the post-peak mechanics behavior of rock samples with a thick wall cylinder structure, damaged rock samples were precast with a new method. The uniaxial compression tests and tri-axial compression tests were conducted on the samples and the test results were compared with that of complete rock samples. The results show that strength attenuation value of the damaged samples increased with the confining pressure and the specific relationship was obtained by nonlinear fitting as (is the strength attenuation value and is the confining pressure); destructiveness of damaged samples was more serious than the complete ones; a new nearly horizontal failure phenomenon appeared under the tri-axial compression and it was more general with the increase of confining pressure. Structure effect of uniaxial strength attenuation was revealed based on the particle flow software system (PFC) and the corresponding theoretical model was found as (is the strength attenuation value under uniaxial compression of any damaged sample with a thick wall cylinder structure; is the strength attenuation value of standard damaged samples under uniaxial compression; is the structure ratio, and are the parameters of the material). Characteristic value of the strength attenuation value under uniaxial compression was obtained by calculation when the structure ratio was indefinitely large.

Effect of Column Parameters on Axial Compression Behavior of Concrete-Filled FRP Tubes

2005 ◽  
Vol 8 (4) ◽  
pp. 443-449 ◽  
Author(s):  
Zhenyu Zhu ◽  
Iftekhar Ahmad ◽  
Amir Mirmiran
Keyword(s):  
Axial Compression ◽  
Experimental Program ◽  
Test Results ◽  
Compression Tests ◽  
Concrete Core ◽  
Compression Behavior ◽  
Reinforced Polymer ◽  
Dowel Action ◽  
Frp Tubes ◽  
Glass Frp

Axial compression tests have shown fiber reinforced polymer (FRP) tubes to significantly enhance both strength and ductility of concrete columns. However, most experiments and associated models typically do not account for the internal reinforcement, size effect of the column, and the end load-bearing conditions of the tube. An experimental program was undertaken to evaluate the effect of these parameters on the performance of CFFT columns. Glass FRP tubes filled with plain, steel-reinforced, and glass FRP-reinforced concrete were tested with and without end grooves, which would prevent the tube from directly bearing of the axial load. The experiments showed the dowel action of the internal reinforcement to improve the ductility of the columns by restraining the lateral dilation of concrete core. Anempirically derived confinement model, augmented with the stress-strain response of the internal reinforcement, showed close agreement with test results.

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 Ultimate Load-Carrying Ability of Rib-Stiffened 2024-T3 and 7075-T6 Aluminium Alloy Panels under Axial Compression

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1176
Author(s):  
Ján Slota ◽  
Andrzej Kubit ◽  
Tomasz Trzepieciński ◽  
Bogdan Krasowski ◽  
Ján Varga
Keyword(s):  
Axial Compression ◽  
Single Point ◽  
Local Buckling ◽  
Image Correlation ◽  
Structural Elements ◽  
Compression Tests ◽  
Buckling Modes ◽  
Stiffened Panels ◽  
Load Carrying ◽  
Different Thickness

Stringer-stiffened panels made of aluminium alloys are often used as structural elements in the aircraft industry. The load-carrying capacity of this type of structure cannot relieve the reduction in strength in the event of local buckling. In this paper, a method of fabrication of rib-stiffened panels made of EN AW-2024-T3 Alclad and EN AW-7075-T6 Alclad has been proposed using single point incremental forming. Panels made of sheets of different thickness and with different values of forming parameters were tested under the axial compression test. A digital image correlation (DIC)-based system was used to find the distribution of strain in the panels. The results of the axial compression tests revealed that the panels had two distinct buckling modes: (i) The panels buckled halfway up the panel height towards the rib, without any appreciable loss of rib stability, and (ii) the rib first lost stability at half its height with associated breakage, and then the panel was deflected in the opposite direction to the position of the rib. Different buckling modes can be associated with the character of transverse and longitudinal springback of panels resulting from local interaction of the rotating tool on the surface of the formed ribs.

scholarly journals Study on the Mechanical Properties of BFRP Tube Confined Concrete Short Columns under Axial Compression

2020 ◽  
Author(s):  
Xindong DING ◽  
Shuqing Wang ◽  
Yu Liu ◽  
Zepeng Zheng
Keyword(s):  
Axial Compression ◽  
Brittle Failure ◽  
Failure Modes ◽  
Concrete Strength ◽  
Steel Tube ◽  
Confined Concrete ◽  
Test Results ◽  
Compression Tests ◽  
Short Columns ◽  
Square Steel Tube

Axial compression tests were carried out on 6 square steel tube confined concrete short columns and 6 BFRP square pipe confined concrete axial compression tests. The concrete strength grades were C30, C40, and C50. The test results show that the failure modes of steel pipe and BFRP pipe are obviously different, and the BFRP pipe undergoes brittle failure. Compared with the short columns of concrete confined by BFRP pipes, the ultimate bearing capacity of axial compression is increased by -76.46%, -76.01%, and -73.06%, and the ultimate displacements are -79.20%, -80.78%, -71.71%.

Effect of Cross Sectional Shape on the Energy Absorbing Characteristics of a Tube under Quasi-Static Loading

2013 ◽  
Vol 315 ◽  
pp. 334-338 ◽  
Author(s):  
Jaffar S. Mohamed Ali ◽  
Kassim A. Abdullah ◽  
Yulfian Aminanda
Keyword(s):  
Energy Absorption ◽  
Axial Compression ◽  
Cross Section ◽  
Cross Sections ◽  
Cross Sectional ◽  
Tube Cross Section ◽  
Deformation Response ◽  
Section Shape ◽  
Energy Absorbing ◽  
Sectional Shape

In this study, numerical simulation of tubes of various cross section under axial compression is carried out using LS-DYNA. The effect of varying configurations of tube cross-section shape on the deformation response, collapse mode and energy absorption characteristics of tubes under quasi-static axial compression have been studied. The validation of the finite element tube model was made by comparison with the experimental results of the square tube subjected to quasi-static axial compression. Tabulated results are presented and plots have been included for the specific energy absorption for different cross sections. The study provides an insight on ways to increasing energy absorption of light weight aluminium tubes.

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