A Strength Model for Square CFT Stub Columns with Compact Sections

2011 ◽  
Vol 94-96 ◽  
pp. 425-430 ◽  
Author(s):  
Zhao Hui Lu ◽  
Yan Gang Zhao ◽  
Zhi Wu Yu
Keyword(s):  
Ultimate Strength ◽  
High Strength ◽  
Steel Tube ◽  
Strength Model ◽  
Steel Tubes ◽  
Composite Action ◽  
Axial Capacity ◽  
Efficient Representation ◽  
Normal Strength ◽  
Stub Columns

This paper presents an investigation of ultimate strength of square CFT stub columns with compact sections. The beneficial composite action between the steel tube and the filled concrete is taken into account and a new analytical model for predicting the axial capacity of square CFT stub columns with compact sections is proposed. Experimental results of 89 axially loaded square CFT stub columns published in the literature are then used to verify the proposed strength model. Results show that the proposed strength model provides a direct, compact, and efficient representation of the ultimate strength of square CFT stub columns made with not only normal strength but also with high strength steel tubes and concrete.

scholarly journals Axial Behavior of Concrete-Filled Double-Skin Tubular Stub Columns Incorporating PVC Pipes

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1434
Author(s):  
Muhammmad Faisal Javed ◽  
Haris Rafiq ◽  
Mohsin Ali Khan ◽  
Fahid Aslam ◽  
Muhammad Ali Musarat ◽  
...  
Keyword(s):  
Steel Tube ◽  
Tube Material ◽  
Steel Tubes ◽  
Tubular Columns ◽  
Axial Capacity ◽  
Double Skin ◽  
Axial Behavior ◽  
Pvc Pipe ◽  
The Cost ◽  
Stub Columns

This experimental study presents concrete-filled double-skin tubular columns and demonstrates their expected advantages. These columns consist of an outer steel tube, an inner steel tube, and concrete sandwiched between two tubes. The influence of the outer-to-inner tube dimension ratio, outer tube to thickness ratio, and type of inner tube material (steel, PVC pipe) on the ultimate axial capacity of concrete-filled double-skin tubular columns is studied. It is found that the yield strength of the inner tube does not significantly affect the ultimate axial capacity of concrete-filled double-skin tubular composites. With the replacement of the inner tube of steel with a PVC pipe, on average, less than 10% strength is reduced, irrespective of size and dimensions of the steel tube. Hence, the cost of a project can be reduced by replacing inner steel tubes with a PVC pipes. Finally, the experimental results are compared with the existing design methods presented in AISC 360-16 (2016), GB51367 (2019), and EC4 (2004). It is found from the comparison that GB51367 (2019) gives better results, followed by AISC (2016) and EC4 (2004).

Finite Element Analysis of RPC-Filled Steel Tube Stub Columns

2011 ◽  
Vol 189-193 ◽  
pp. 1906-1909 ◽  
Author(s):  
Hua Luo ◽  
Zhi Gang Yan ◽  
Ming Zhe An
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Strength ◽  
Element Model ◽  
Steel Tube ◽  
Nonlinear Material ◽  
Steel Tubes ◽  
Element Analysis ◽  
Reactive Powder ◽  
Stub Columns

Reactive Powder Concrete (RPC) is a kind of cement-based composite which has ultra-high strength, high ductility and durability. RPC has great fragility, bad ductility and bursting fragility destruction subjected to high or complicated stress. The fragility performance of RPC will be improved when RPC is cast in steel tubes. The behavior of axially loaded RPC-filled steel tube circular stub columns is presented in this discussion according to the experiment and finite element analysis. An accurate finite element model was developed to carry out the analysis. Accurate nonlinear material models for confined concrete and steel tubes were used. The results obtained from the finite element analysis were verified against experimental results.

Strength of Square CFT Stub Columns with Slender Sections

2012 ◽  
Vol 166-169 ◽  
pp. 1050-1053
Author(s):  
Zhao Hui Lu ◽  
Yan Gang Zhao ◽  
Zhi Wu Yu
Keyword(s):  
Ultimate Strength ◽  
Experimental Results ◽  
Strength Model ◽  
Efficient Representation ◽  
Axially Loaded ◽  
Definition Of ◽  
Stub Columns

This paper presents an investigation of ultimate strength of square CFT stub columns with slender sections. The definition of square CFT stub columns with slender sections is discussed and a new strength model is proposed. Experimental results of 31 axially loaded square CFT stub columns published in the literature are then used to verify the proposed strength model. Results show that the proposed strength model provides a direct, compact, and efficient representation of the ultimate strength of square CFT stub columns with slender sections.

Eccentric compression tests and design of welded steel tube strengthened RC stub columns with high-strength grout

2021 ◽  
Vol 35 ◽  
pp. 102072
Author(s):  
Benhao Gao ◽  
Jingfeng Wang ◽  
Qihan Shen ◽  
Chenggang Wang ◽  
Zhonghua Yu
Keyword(s):  
High Strength ◽  
Steel Tube ◽  
Compression Tests ◽  
Welded Steel ◽  
Eccentric Compression ◽  
Stub Columns

scholarly journals Experimental and Numerical Study on the Compression Behavior of Square Concrete-Filled Steel Tube Stub Columns with Steel Fiber-Reinforced High-Strength Concrete

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Hyung-Suk Jung ◽  
Baek-Il Bae ◽  
Hyun-Ki Choi ◽  
Joo-Hong Chung ◽  
Chang-Sik Choi ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Yield Strength ◽  
Parametric Study ◽  
High Strength Concrete ◽  
High Performance ◽  
Steel Fiber ◽  
High Strength ◽  
Steel Tube ◽  
Stub Columns ◽  
Strain Increase

This study was conducted to evaluate the applicability of concrete-filled steel tube (CFT) columns made from high-performance construction materials. KBC2016, South Korea’s current building code, limits the maximum compressive strength of concrete at 70 MPa and the maximum yield strength of steel at 650 MPa. Similar restrictions to material properties are imposed on major composite structural design parameters in other countries worldwide. With the recent acceleration of the pace of development in the field of material technology, the compressive strength of commercial concrete has been greatly improved and the problem of low tensile strength, known to be the major limitation of concrete, is being successfully addressed by adding fiber reinforcement to concrete. Therefore, the focus of this study was to experimentally determine the strength and ductility enhancement effects, which depend on material composition. To this end, we performed concentric axial loading tests on CFT stub columns made from steel with a yield strength of 800 MPa and steel fiber-reinforced high-strength concrete. By measuring the strain at the yield point of CFT steel during the test, we could determine whether steel yields earlier than ultimate failure load of the member, which is a key design concept of composite structures. The analysis results revealed that the yield point of steel preceded that of concrete on the stress-strain curve by the concurrent action of the strain increase at the maximum strength, attributable to the high compressive strength and steel fiber reinforcement, and the strain increase induced by the confining stress of the steel tube. Additionally, we performed parametric study using ABAQUS to establish the broad applications of CFT using high-performance materials, with the width-to-thickness ratio as the main parameter. Parametric study was undertaken as experimental investigation was not feasible, and we reviewed the criteria for limiting the width-to-thickness ratio as specified in the current building code.

Theoretical Study on Axial Capacity of CFRP Reinforced Self-Stressing Concrete Filled Steel Tubes

2011 ◽  
Vol 121-126 ◽  
pp. 3025-3029
Author(s):  
Hui Li ◽  
Jun Deng ◽  
Jun Hong Lin
Keyword(s):  
Theoretical Study ◽  
Steel Tube ◽  
Limit States ◽  
Steel Tubes ◽  
Concrete Core ◽  
Cfrp Sheets ◽  
Axial Capacity ◽  
Ultimate Equilibrium ◽  
Concrete Filled Steel Tubes ◽  
Cfrp Wrapping

Since the expansion of the cement during curing was constraint by the steel tube, the concrete core in the self-stressing concrete-filled steel tubes (SSCFST) is under tri-axially compression before applying load, which increases the axial capacity of the SSCFST. In addition, Carbon fiber reinforced polymer (CFRP) wrapping can avoid bucking of the steel tube, increase the axial capacity and improve the durability of SSCFST. This study presents a theoretical study on axial capacity of the SSCFST wrapped with CFRP sheets. Several basic assumptions are proposed. The ultimate equilibrium method was employed to analyze the axial capacity, of which two limit states, including steel tube bucking and CFRP sheets rupturing were considered. The analytical results from an example show that the initial self-stress improves axial capacity of the SSCFST by about 30% and the CFRP reinforcement improves axial capacity by about 15%.

Influence of Lubricants on Advanced High Strength Steel Tubes in Bending Process

2009 ◽  
Author(s):  
Ramakrishna Koganti ◽  
Sergio Angotti ◽  
Isadora van Riemsdijk ◽  
Robert C. Nelson ◽  
Jill Smith
Keyword(s):  
High Strength Steel ◽  
High Strength ◽  
Steel Tube ◽  
Application Site ◽  
Structural Components ◽  
Advanced High Strength Steel ◽  
Steel Tubes ◽  
Automotive Body ◽  
Bending Process ◽  
Lubricant Performance

To reach safety, emissions, and cost objectives, manufacturers of automotive body structural components shape thin gauge, high strength steel tube using a series of manufacturing steps that often include bending, preforming and hydroforming. Challenging grades and bend severity require a sensitive optimization of the tubular bending process. Lubricants play a significant role in establishing a successful bending process. In this study, the performance of two lubricants, Hydrodraw 551 and HFO 20, were investigated for bending Dual Phase 780 (DP780) and High Strength Low Alloy 350 (HSLA350) thin-walled steel tubes. Formability success was evaluated in terms of wrinkling, thinning strain and final geometry. Lubricant performance was found to be sensitive to grade and application site. HFO 20 was found to be a poor choice for bending DP780 tube.

scholarly journals Mechanical properties and corrosion resistance of normal strength and high strength steels in chloride solution

2011 ◽  
Vol 7 (2) ◽  
pp. 94-100 ◽  
Author(s):  
Ahmad Rahbar Ranji ◽  
Amir Hamed Zakeri
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Corrosion Resistance ◽  
Ultimate Strength ◽  
Chloride Solution ◽  
High Strength Steels ◽  
High Strength ◽  
Carbon Steels ◽  
Tension Test ◽  
Normal Strength

The corrosion resistance (weight loss) and mechanical properties (i.e. yield strength, ultimate strength and elongation) for three carbon steels, normal strength and high strength steels using tension test are investigated. The specimens are kept in chloride solution (20% NaCl) up to 240 hours. At every 48 hours, thickness and weight loss is measured and tension test is carried out. It was found that the susceptibility of the steels to corrosion based on their weight loss were identical prior to 144 hours, after that is accelerated for high strength steel. In addition, it was found that manganese (Mn) has reduced corrosion rate at early stage of corrosion. The change in mechanical properties by corrosion for all steels are the same, and ultimate strength is reduced, which for limit state design of aged structure should be taken into account.DOI: 10.3329/jname.v7i2.5309

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