scholarly journals Transverse reinforcement contribution in shear – remarks from experimental research

2014 ◽  
Vol 13 (3) ◽  
pp. 135-142
Author(s):  
Rafał Ostromęcki
Keyword(s):  
Experimental Research ◽  
Shear Force ◽  
Shear Loading ◽  
Transverse Force ◽  
Constitutive Law ◽  
Transverse Reinforcement ◽  
Longitudinal Reinforcement ◽  
Simply Supported

The results of research for transverse reinforcement contribution in shear are presented in the article. Tests were made on the single span, simply supported beams. Resistance gauges were used to measure the strain on the stirrups at points crossing the artificial crack, formed with the thin, greased plate. Basing on the constitutive law for the stirrups steel derived in test, the force in stirrups was invented VEd,s. Such an attitude allowed to compare the force carried by stirrups VEd,s with the actual shear loading VEd. In the performed test made the stirrups contribution was between 52 and 72% of shear force. It was also noticed, that longitudinal reinforcement carried some transverse force as well. This ability is usually neglected in shear theories.

Discrete versus average integration in shear assessment of spiral links

2009 ◽  
Vol 36 (2) ◽  
pp. 171-179 ◽  
Author(s):  
Kamal Jaafar
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Circular Cross Section ◽  
Shear Resistance ◽  
Shear Loading ◽  
Reinforced Concrete Beams ◽  
Transverse Reinforcement ◽  
Longitudinal Reinforcement ◽  
Concrete Members ◽  
Combined Action

Common transverse reinforcement of reinforced concrete members with circular cross section consists of round ties or spirals. Its purpose in members that are not subjected to significant shear loading is to provide proper confinement for concrete, and eliminate buckling of the longitudinal reinforcement bars. If spirals are to be used as both a shear resister and confining enabler for reinforced concrete beams, then under combined action of moment and shear, spirals will be required to provide or contribute to proper shear resistance. Hence a proper assessment for spiral shear contribution is required.

Load Bearing Behavior of UHPFRC Beams Reinforced with High Grade Steel

2014 ◽  
Vol 629-630 ◽  
pp. 551-559 ◽  
Author(s):  
Norbert Randl ◽  
Tamás Mészöly
Keyword(s):  
Cross Section ◽  
Shear Loading ◽  
Load Level ◽  
Fiber Reinforced Concrete ◽  
Constitutive Law ◽  
Small Scale ◽  
Longitudinal Reinforcement ◽  
Compression Tests ◽  
Load Bearing ◽  
Four Point Bending

In the frame of a research project funded by the Austrian Research Foundation (FFG) a series of 10 UHPC beams with an I-shaped cross-section and a full length of 3.5 m was produced and subjected to four-point bending and shear loading respectively until failure. The amount of longitudinal reinforcement as well as the fiber content was varied. The tensile strength of the longitudinal reinforcement was 800 to 1100 MPa. Several circular shaped openings were foreseen in order to facilitate potential installation crossings. The cross-section was optimized for load bearing capacity and ductility. Special attention was paid on the crack development and SLS criteria as well as the ductility after reaching ultimate load level. The full constitutive law of the applied UHPFRC mixture was derived from compression tests, uniaxial tension tests and several small scale four-point bending tests. On the basis of the derived constitutive law in tension, the UHPFRC was classified as “type 2 – low strain hardening” fiber reinforced concrete.

scholarly journals Research on Concrete Columns Reinforced with New Developed High-Strength Steel under Eccentric Loading

2019 ◽  
Author(s):  
Yonghui Hou ◽  
Shuangyin Cao ◽  
Xiangyong Ni ◽  
Yizhu Li
Keyword(s):  
Yield Strength ◽  
Bearing Capacity ◽  
High Strength Steel ◽  
High Strength ◽  
Concrete Columns ◽  
Lower Amount ◽  
Transverse Reinforcement ◽  
Longitudinal Reinforcement ◽  
Small Eccentricity ◽  
Failure Patterns

The use of new developed high-strength steel in concrete members can reduce steel bars congestion and construction costs. This research aims to study the behavior of concrete columns reinforced with new developed high-strength steel under eccentric loading. Ten reinforced concrete columns were fabricated and tested. The test variables are transverse reinforcement amount and yield strength, eccentricity, and longitudinal reinforcement yield strength. The failure patterns are compression and tensile failure for columns subjected to small eccentricity and large eccentricity, respectively. The same level of post-peak deformability and ductility only can be obtained with lower amount of transverse reinforcement when high-strength transverse reinforcements are used in columns subjected to small eccentricity. The high-strength longitudinal reinforcement can improve bearing capacity and post-peak deformability of concrete columns. Besides, three different equivalent rectangular stress block (ERSB) parameters in predicting bearing capacity of columns with high-strength steel were discussed based on test and simulated results. It is concluded that the Code of GB 50010-2010 overestimates the bearing capacity of columns with high-strength steel, whereas bearing capacities computed using Codes of ACI 318-14 and CSA A23.3-04 agree well with test results.

Flexure of a Circular Plate With a Ring of Holes

1962 ◽  
Vol 29 (3) ◽  
pp. 489-496 ◽  
Author(s):  
H. Kraus
Keyword(s):  
Circular Plate ◽  
Shear Force ◽  
General Boundary Condition ◽  
Uniform Pressure ◽  
Simply Supported ◽  
Moment Distribution ◽  
Theory Of Plates ◽  
Circular Holes ◽  
The Moment ◽  
Kirchhoff Theory

The problem of the moment distribution resulting from a uniform pressure load acting over the surface of a circular plate containing a ring of equally spaced circular holes with, and without, a central circular hole is solved within the framework of the Poisson-Kirchhoff theory of plates. A general boundary condition is applied at the outer rim of the plate to make the solution valid for a range of conditions from the simply supported case to the clamped case. The edges of the perforations are allowed to be either free or to have a net shear force acting. Numerical results in the form of curves are given for typical cases, and the results of a photoelastic test are also presented.

Vibrational analysis of sandwich sectorial plates with functionally graded sheets reinforced by aggregated carbon nanotube

2018 ◽  
Vol 22 (5) ◽  
pp. 1496-1541 ◽  
Author(s):  
Vahid Tahouneh
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Boundary Conditions ◽  
Single Walled Carbon Nanotubes ◽  
Functionally Graded ◽  
Constitutive Law ◽  
Two Dimensional ◽  
Simply Supported ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes

In the present work, by considering the agglomeration effect of single-walled carbon nanotubes, free vibration characteristics of functionally graded nanocomposite sandwich sectorial plates are presented. The volume fractions of randomly oriented agglomerated single-walled carbon nanotubes are assumed to be graded in the thickness direction. To determine the effect of carbon nanotube agglomeration on the elastic properties of carbon nanotube-reinforced composites, a two-parameter micromechanical model of agglomeration is employed. In this research work, an equivalent continuum model based on the Eshelby–Mori–Tanaka approach is considered to estimate the effective constitutive law of the elastic isotropic medium (matrix) with oriented straight carbon nanotubes. The two-dimensional generalized differential quadrature method as an efficient and accurate numerical tool is used to discretize the equations of motion and to implement the various boundary conditions. The proposed sectorial plates are simply supported at radial edges, while all possible combinations of free, simply supported, and clamped boundary conditions are applied to the other two circular edges. The benefit of using the considered power-law distribution is to illustrate and present useful results arising from symmetric and asymmetric profiles. The effects of agglomeration, geometrical, and material parameters together with the boundary conditions on the frequency parameters of the sandwich functionally graded nanocomposite plates are investigated. It is shown that the natural frequencies of structure are seriously affected by the influence of carbon nanotubes agglomeration. This study serves as a benchmark for assessing the validity of numerical methods or two-dimensional theories used to analyze the sandwich sectorial plates.

scholarly journals Shear strength analysis of slabs without transverse reinforcement under concentrated loads according to ABNT NBR 6118:2014

2019 ◽  
Vol 12 (3) ◽  
pp. 658-693
Author(s):  
A. M. D. SOUSA ◽  
M. K. EL DEBS
Keyword(s):  
Shear Strength ◽  
Shear Force ◽  
Highway Bridges ◽  
Analytical Models ◽  
Strength Analysis ◽  
Transverse Reinforcement ◽  
Concentrated Loads ◽  
Technical Literature ◽  
Experimental Database ◽  
Small Areas

Abstract Concentrated loads in slabs without transverse reinforcement, usual in highway bridges, result in the horizontal spreading of the shear force towards the supports, situation in which not all the slab width contributes in the shear strength. Based on this, the analytical models of shear strength and punching capacity in slabs may not be suitable to deal with this loading. Since this topic is not widely discussed in the national technical literature, the paper aims to present contributions to these analyses with a focus on the accuracy level of the shear strength analytical models recommended by ABNT NBR 6118:2014. Therefore, the models available in the Brazilian code were applied to an experimental database with 118 test results and the results obtained by the Brazilian and European codes were compared. The results demonstrated that, as presented in the Brazilian code, shear strength model in one-way slabs can lead to unsafe resistance predictions while the punching capacity model can lead to very conservative predictions. From the analysis, it is concluded that considering the reduction of the shear force, in the case of loads distributed in small areas close to the support in slabs, and the use of more suitable procedures to define the effective width, it is possible to improve the level of accuracy of relations between experimental and theoretical values, but this still leads to high percentages of unsafe predictions of resistance (> 40%).

scholarly journals Flexural Capacity of Steel-Concrete Composite Beams under Hogging Moment

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Jing Liu ◽  
Fa-xing Ding ◽  
Xue-mei Liu ◽  
Zhi-wu Yu ◽  
Zhe Tan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Flexural Strength ◽  
Composite Beams ◽  
The Other ◽  
Transverse Reinforcement ◽  
Beam Length ◽  
Simply Supported ◽  
Shear Connection ◽  
Abaqus Software

This study investigates the flexural strength of simply supported steel-concrete composite beams under hogging moment. A total of 24 composite beams are included in the experiments, and ABAQUS software is used to establish finite element (FE) models that can simulate the mechanical properties of composite beams. In a parametric study, the influences of several major parameters, such as shear connection degree, stud arrangement and diameter, longitudinal and transverse reinforcement ratios, loading manner, and beam length, on flexural strength were investigated. Thereafter, three standards, namely, GB 50017, Eurocode 4, and BS 5950, were used to estimate the flexural strength of the composite beams. These codes were also compared with experimental and numerical results. Results indicate that GB 50017 may provide better estimations than the other two codes.

scholarly journals Research on Concrete Columns Reinforced with New Developed High-Strength Steel under Eccentric Loading

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2139 ◽  
Author(s):  
Yonghui Hou ◽  
Shuangyin Cao ◽  
Xiangyong Ni ◽  
Yizhu Li
Keyword(s):  
Yield Strength ◽  
Bearing Capacity ◽  
High Strength Steel ◽  
High Strength ◽  
Concrete Columns ◽  
Lower Amount ◽  
Transverse Reinforcement ◽  
Longitudinal Reinforcement ◽  
Small Eccentricity ◽  
Failure Patterns

The use of new developed high-strength steel in concrete members can reduce steel bar congestion and construction costs. This research aims to study the behavior of concrete columns reinforced with new developed high-strength steel under eccentric loading. Ten reinforced concrete columns were fabricated and tested. The test variables were the transverse reinforcement amount and yield strength, eccentricity, and longitudinal reinforcement yield strength. The failure patterns were compression and tensile failure for columns subjected to small eccentricity and large eccentricity, respectively. The same level of post-peak deformability and ductility could only be obtained with a lower amount of transverse reinforcement when high-strength transverse reinforcements were used in columns subjected to small eccentricity. The high-strength longitudinal reinforcement improved the bearing capacity and post-peak deformability of the concrete columns. Furthermore, three different equivalent rectangular stress block (ERSB) parameters for predicting the bearing capacity of columns with high-strength steel are discussed based on test and simulated results. It is concluded that the China Code GB 50010-2010 overestimates the bearing capacity of columns with high-strength steel, whereas the bearing capacities computed using the America Code ACI 318-14 and Canada Code CSA A23.3-04 agree well with the test results.

scholarly journals Sliding-induced adhesion of stiff polymer microfibre arrays. I. Macroscale behaviour

2008 ◽  
Vol 5 (25) ◽  
pp. 835-844 ◽  
Author(s):  
Jongho Lee ◽  
Carmel Majidi ◽  
Bryan Schubert ◽  
Ronald S Fearing
Keyword(s):  
Elastic Modulus ◽  
Contact Area ◽  
Shear Force ◽  
Contact Region ◽  
Pure Shear ◽  
Shear Loading ◽  
High Shear ◽  
Polypropylene Fibres ◽  
True Contact Area ◽  
True Contact

Gecko-inspired microfibre arrays with 42 million polypropylene fibres cm −2 (each fibre with elastic modulus 1 GPa, length 20 μm and diameter 0.6 μm) were fabricated and tested under pure shear loading conditions, after removing a preload of less than 0.1 N cm −2 . After sliding to engage fibres, 2 cm 2 patches developed up to 4 N of shear force with an estimated contact region of 0.44 cm 2 . The control unfibrillated surface had no measurable shear force. For comparison, a natural setal patch tested under the same conditions on smooth glass showed approximately seven times greater shear per unit estimated contact region. Similar to gecko fibre arrays, the synthetic patch maintains contact and increases shear force with sliding. The high shear force observed (approx. 210 nN per fibre) suggests that fibres are in side contact, providing a larger true contact area than would be obtained by tip contact. Shear force increased over the course of repeated tests for synthetic patches, suggesting deformation of fibres into more favourable conformations.

Study on External Prestressing Connection Mode of the Simply-Supported and Continued Structure System

2013 ◽  
Vol 405-408 ◽  
pp. 1513-1516
Author(s):  
Xiu Juan Jiang ◽  
Rong Da Li ◽  
Jun Yan Wu ◽  
Jian Xin Liu
Keyword(s):  
Numerical Simulation ◽  
Experimental Research ◽  
Continuous System ◽  
Simulation Method ◽  
Internal Force ◽  
Element Analysis ◽  
Structure System ◽  
Simply Supported ◽  
External Prestressing

Simply supported beam by applying the external prestressing change as a continuous system can be a substantial increase in the bridge carrying capacity, but more complex in vitro beam connection segment force. To study the forced state of external prestressing connection mode of the simply-supported and continued structure system, it is studied by both the way of numerical simulation using the finite element analysis software ANSYS and experimental research. The physical model to simulate the prestressed concrete structure and the test process are described. By comparing the results of numerical simulation and experimental research, the stress stage of the connection mode is divided. As a result, a simplified method of calculating the deflection based on the elastic theory is proposed. The internal force redistribution of the structure is also determined. The results of the numerical simulation method are reliable because it is similar to measured results.

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