ESTIMATION OF AXIAL-FORCE SHARING OF CROSS-SECTIONAL LOSS STEEL MEMBERS REPAIRED BY PATCH PLATES WITH HIGH-STRENGTH BOLTS UNDER AXIAL LOADING

2021 ◽  
Vol 77 (1) ◽  
pp. 93-106
Author(s):  
Toshiyuki ISHIKAWA ◽  
Ryota YAEGAKI
Keyword(s):  
Axial Force ◽  
Axial Loading ◽  
High Strength ◽  
Cross Sectional ◽  
Steel Members ◽  
Force Sharing

A self-locking steel bearing connection for circular reinforced concrete columns

2019 ◽  
Vol 22 (12) ◽  
pp. 2605-2619
Author(s):  
Denghu Jing ◽  
Shuangyin Cao ◽  
Theofanis Krevaikas ◽  
Jun Bian
Keyword(s):  
Reinforced Concrete ◽  
Cross Sections ◽  
Axial Loading ◽  
High Strength ◽  
Axial Stiffness ◽  
Concrete Column ◽  
Reinforced Concrete Column ◽  
Cross Sectional ◽  
Locking Mechanism ◽  
The Cross

This article proposes a new connection between a steel bearing and a reinforced concrete column, which is mainly used for provisionally providing jack support in existing reinforced concrete structures. In this suggested connection joint, the steel bearing consisted of two or four symmetrical components assembled by high-strength bolts, which surrounds the reinforced concrete column by a tapered tube and balances the vertical load via the friction force between the tapered tube and concrete, that is, through a self-locking mechanism. The proposed connection joint can be assembled easily at a construction site and can also be disassembled and reused many times. To demonstrate the feasibility of this type of connection joint, a simple test was conducted to illustrate the concept, that is, a total of four medium-scale steel bearing–reinforced concrete column connections with circular cross sections were fabricated and tested under axial loading. The test results showed that the steel bearing–reinforced concrete column connection based on self-locking mechanism exhibited good working performance. Furthermore, a simplified formula to predict the axial stiffness of the connection joint was presented. From the tests and the proposed formula, the most important factors that influence the axial stiffness of this type of connection joint on the premise of an elastic working state are the slope of the tapered tube, the height of the steel bearing, the thickness of the tapered tube, the cross section of the reinforced concrete column, the cross-sectional area of all the connecting bolts, the proportion of the number of top bolts, the area of the top ring plate, and the effective contact area ratio.

scholarly journals A Critical Review on Optimization of Cold-Formed Steel Members for Better Structural and Thermal Performances

Buildings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 34
Author(s):  
Hao Liang ◽  
Krishanu Roy ◽  
Zhiyuan Fang ◽  
James B. P. Lim
Keyword(s):  
Thermal Performance ◽  
Carbon Dioxide Emissions ◽  
Weight Ratio ◽  
High Strength ◽  
Energy Performance ◽  
Future Research ◽  
Total Energy Consumption ◽  
Cross Sectional ◽  
Steel Members ◽  
Cold Formed Steel

The construction and building sectors are currently responsible globally for a significant share of the total energy consumption and energy-related carbon dioxide emissions. The use of Modern Methods of Construction can help reduce this, one example being the use of cold-formed steel (CFS) construction. CFS channel sections have inherent advantages, such as their high strength-to-weight ratio and excellent potential for recycling and reusing. CFS members can be rolled into different cross-sectional shapes and optimizing these shapes can further improve their load-bearing capacities, resulting in a more economical and efficient building solution. Conversely, the high thermal conductivity of steel can lead to thermal bridges, which can significantly reduce the building’s thermal performance and energy efficiency. Hence, it is also essential to consider the thermal energy performance of the CFS structures. This paper reviews the existing studies on the structural optimization of CFS sections and the thermal performance of such CFS structures. In total, over 160 articles were critically reviewed. The methodologies used in the existing literature for optimizing CFS members for both structural and thermal performances have been summarized and presented systematically. Research gaps from the existing body of knowledge have been identified, providing guidelines for future research.

Eddy current based evaluation of axial force of high-strength bolts

2021 ◽  
Author(s):  
Ayako Akutsu ◽  
Sanjeema Bajracharya ◽  
Eiichi Sasaki ◽  
Tetsuhiro Shimozato ◽  
Masayuki Tai
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Axial Force ◽  
Eddy Current ◽  
High Strength ◽  
Current Method ◽  
Eddy Current Method ◽  
High Strength Bolt ◽  
Steel Members ◽  
Over 40 Years

<p>Many bridges have been in service for over 40 years and face to the repapering or reinforcing period due to deterioration. Particularly, in a high-strength bolts used for joints may be loosened due to co-rotation, corrosion, or vibration caused by the vehicles. Thus, it is important to evaluate an axial force of the high-strength bolts. In this research, an axial force evaluation of high-strength bolt using eddy current that does not require measurement preparation has been investigated. The eddy current method is capable of capturing the change in permeability of steel members due to the stress change. Further, the stress distribution of the bolt head is assumed uniform without directionality. Therefore, a numerical simulation and an experiment that measures the output signal of the eddy current probe while introducing axial force to the high-strength bolt has conducted.</p>

The stabilization of B.C.C. Cu in Cu/Nb nanolayered composites

1996 ◽  
Vol 54 ◽  
pp. 228-229
Author(s):  
H. Kung ◽  
A.J. Griffin ◽  
Y.C. Lu ◽  
K.E. Sickafus ◽  
T.E. Mitchell ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Layer Thickness ◽  
Volume Fraction ◽  
Ion Beam ◽  
High Strength ◽  
Cross Sectional ◽  
Metastable Structure ◽  
High Resolution Tem ◽  
Potential Improvement ◽  
Two Phases

Materials with compositionally modulated structures have gained much attention recently due to potential improvement in electrical, magnetic and mechanical properties. Specifically, Cu-Nb laminate systems have been extensively studied mainly due to the combination of high strength, and superior thermal and electrical conductivity that can be obtained and optimized for the different applications. The effect of layer thickness on the hardness, residual stress and electrical resistivity has been investigated. In general, increases in hardness and electrical resistivity have been observed with decreasing layer thickness. In addition, reduction in structural scale has caused the formation of a metastable structure which exhibits uniquely different properties. In this study, we report the formation of b.c.c. Cu in highly textured Cu/Nb nanolayers. A series of Cu/Nb nanolayered films, with alternating Cu and Nb layers, were prepared by dc magnetron sputtering onto Si {100} wafers. The nominal total thickness of each layered film was 1 μm. The layer thickness was varied between 1 nm and 500 nm with the volume fraction of the two phases kept constant at 50%. The deposition rates and film densities were determined through a combination of profilometry and ion beam analysis techniques. Cross-sectional transmission electron microscopy (XTEM) was used to examine the structure, phase and grain size distribution of the as-sputtered films. A JEOL 3000F high resolution TEM was used to characterize the microstructure.

Correlation of axial loaded magnetic resonance imaging with clinical symptoms in lumbar spinal canal stenosis patients

MedPharmRes ◽  
2019 ◽  
Vol 2 (4) ◽  
pp. 15-19
Author(s):  
Son Nguyen ◽  
Son Vi ◽  
Hoat Luu ◽  
Toan Do
Keyword(s):  
Spinal Canal ◽  
Clinical Symptoms ◽  
Axial Loading ◽  
Spinal Canal Stenosis ◽  
Leg Pain ◽  
Cross Sectional ◽  
Canal Stenosis ◽  
Conventional Mri ◽  
Frame System ◽  
Lumbar Spinal

There are cases when symptoms are available but no abnormal stenosis is found in MRI and vice versa. Axial-loaded MRI has been shown that it can demonstrate more accurately the real status of spinal canal stenosis than conventional MRI. This is the first time we applied a new system that we have recreated from the original loading frame system in order to fit with the demands of Vietnamese people. Sixty-two patients were selected from Phu Tho Hospital in Phu Tho Province, Vietnam, who fulfilled the inclusion criteria. The Anterior-posterior diameter (APD), Dura Cross-sectional Area (DSCA) in conventional MRI and axial loaded MRI, and changes in APD and DCSA were determined at the single most constricted intervertebral level. The APD and DCSA in axial loaded MRI had very good significant correlations with VAS for back pain (rs=0.83, 0.79), leg pain (rs=0.69, 0.57) and JOA score (rs=0.70, 0.65). APD and DCSA in axial loaded MRI significantly correlated with the severity of symptoms. Our axial loading MRI provides more valuable information than the conventional MRI for assessing patients with LSCS.

scholarly journals Experimental Investigation into Corrosion Effect on Mechanical Properties of High Strength Steel Bars under Dynamic Loadings

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Hui Chen ◽  
Jinjin Zhang ◽  
Jin Yang ◽  
Feilong Ye
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Dynamic Loading ◽  
High Strength Steel ◽  
High Strength ◽  
Tensile Tests ◽  
Reinforcing Steel ◽  
Test Results ◽  
Cross Sectional ◽  
Steel Bars

The tensile behaviors of corroded steel bars are important in the capacity evaluation of corroded reinforced concrete structures. The present paper studies the mechanical behavior of the corroded high strength reinforcing steel bars under static and dynamic loading. High strength reinforcing steel bars were corroded by using accelerated corrosion methods and the tensile tests were carried out under different strain rates. The results showed that the mechanical properties of corroded high strength steel bars were strain rate dependent, and the strain rate effect decreased with the increase of corrosion degree. The decreased nominal yield and ultimate strengths were mainly caused by the reduction of cross-sectional areas, and the decreased ultimate deformation and the shortened yield plateau resulted from the intensified stress concentration at the nonuniform reduction. Based on the test results, reduction factors were proposed to relate the tensile behaviors with the corrosion degree and strain rate for corroded bars. A modified Johnson-Cook strength model of corroded high strength steel bars under dynamic loading was proposed by taking into account the influence of corrosion degree. Comparison between the model and test results showed that proposed model properly describes the dynamic response of the corroded high strength rebars.

Strain-Rate Effect on the Tensile Behaviour of High Strength Alloys

2011 ◽  
Vol 82 ◽  
pp. 124-129 ◽  
Author(s):  
Ezio Cadoni ◽  
Matteo Dotta ◽  
Daniele Forni ◽  
Stefano Bianchi
Keyword(s):  
Strain Rate ◽  
Rate Sensitivity ◽  
High Strength ◽  
Constitutive Law ◽  
Tensile Behaviour ◽  
Strain Rates ◽  
Cross Sectional ◽  
Split Hopkinson Tensile Bar ◽  
Wide Range ◽  
First Results

In this paper the first results of the mechanical characterization in tension of two high strength alloys in a wide range of strain rates are presented. Different experimental techniques were used for different strain rates: a universal machine, a Hydro-Pneumatic Machine and a JRC-Split Hopkinson Tensile Bar. The experimental research was developed in the DynaMat laboratory of the University of Applied Sciences of Southern Switzerland. An increase of the stress at a given strain increasing the strain-rate from 10-3 to 103 s-1, a moderate strain-rate sensitivity of the uniform and fracture strain, a poor reduction of the cross-sectional area at fracture with increasing the strain-rate were shown. Based on these experimental results the parameters required by the Johnson-Cook constitutive law were determined.

Hot Spline Forming of Ultra-High Strength Steel Gear Drum Using Resistance Heating

2014 ◽  
Vol 622-623 ◽  
pp. 201-206 ◽  
Author(s):  
Kenichiro Mori ◽  
Tomoyoshi Maeno ◽  
Shohei Nakamoto
Keyword(s):  
Deep Drawing ◽  
High Strength Steel ◽  
Side Wall ◽  
High Strength ◽  
Axial Direction ◽  
Resistance Heating ◽  
Sectional Area ◽  
Forming Process ◽  
Cross Sectional ◽  
Ultra High Strength Steel

A hot spline forming process of die-quenched gear drums using resistance heating of a side wall of a cup formed by cold deep drawing and ironing was developed. The side wall having uniform cross-sectional area is resistance-heated by passage of the current in the axial direction, the heated side wall of the drawn cup is ironed and is finally die-quenched. The gear drum was successfully formed and the hardness was between 400 and 500 HV. Not only the formability was improved but also the formed dram was hardly oxidised because of rapid resistance heating.

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