scholarly journals Assessment of the early-age strains and stresses in 2D restrained self-stressed members

2020 ◽  
Vol 19 (4) ◽  
pp. 085-094
Author(s):  
Viktar V. Tur ◽  
Volha H. Sannikava
Keyword(s):  
Analytical Approach ◽  
Experimental Results ◽  
Development Model ◽  
Early Age ◽  
Steel Tubes ◽  
Mesh Reinforcement ◽  
Centre Of Gravity ◽  
Expansive Concrete ◽  
Iterative Procedures ◽  
Concrete Filled Steel Tubes

The paper presents the implementation of the modified strains development model (MSDM) for the two-way restrained self-stressed members such as expansive concrete-filled steel tubes and expansive concrete plane elements with arbitrary orthogonal reinforcement. The analytical approach allows defining the restrained strains and stresses in any 2D restraint conditions by following the iterative procedures and accounting for the elastic-plastic behaviour of expansive concrete at an early age. The consistency of the proposed method was confirmed by assessing the experimental results of the two series of the expansive concrete-filled steel tubes and three series of the expansive concrete plane members with mesh reinforcement in the centre of gravity.

scholarly journals Analytical Model for Restraint Strains and Self-stressed in Expansive Concrete Filled Steel Tubes (ECFST) estimation

2020 ◽  
pp. 93-98
Author(s):  
Viktar V. Tur ◽  
Radoslaw Duda ◽  
Dina Khmaruk ◽  
Viktar Basav
Keyword(s):  
Experimental Data ◽  
Experimental Studies ◽  
Steel Tube ◽  
Development Model ◽  
Steel Tubes ◽  
Concrete Core ◽  
Expansive Concrete ◽  
Proposed Model ◽  
Comparison Results ◽  
Concrete Filled Steel Tubes

In this paper, a modified strains development model (MSDM) for expansive concrete-filled steel tube (ECFST) was formulated and verified on the experimental data, obtained from testing specimens on the expansion stage. The modified strain development model for restraint strains and self-stresses values estimation in concrete with high expansion energy capacity under any type of the symmetrical and unsymmetrical finite stiffness restraint conditions was proposed. Based on proposed MSDM a new model for expansive concrete-filled steel tubes is developed. The main difference between this model and other previously developed models consists in taking into account in the basic equations an induced force in restrain that is considered as an external load applied to the concrete core of the member. For verification of the proposed model-specific experimental studies were performed. As follows from comparison results restrained expansion strains values calculated following the proposed model shows good compliance with experimental data. The values predicted by the proposed MSDM for concrete-filled steel and obtained experimental data demonstrated good agreement that confirms the validity of the former.

scholarly journals The modified early age strains development model for the case of two-way restraint conditions

2021 ◽  
Vol 350 ◽  
pp. 00010
Author(s):  
Volha Sannikava ◽  
Viktar Tur
Keyword(s):  
Analytical Model ◽  
Experimental Results ◽  
Development Model ◽  
Early Age ◽  
Plastic Behavior ◽  
Stress Strain ◽  
Expansive Concrete ◽  
Proposed Model ◽  
Concrete Elements ◽  
Expansion Period

This paper proposes a design model (2D MSDM) for assessment the early-age stress-strain parameters of two-axially restrained expansive concrete elements. The analytical model allows defining the restrained expansion strains and corresponding self-stresses in case of arbitrary restraint conditions in orthogonal directions by taking into consideration the elastic-plastic behavior of concrete during the expansion period. The results of solution according to the proposed model were compared with the experimental results of expansive concrete elements with orthogonal confinement carried out by authors and other researchers.

Behavior of CFRP-confined reactive powder concrete-filled steel tubes under axial compression

2020 ◽  
pp. 136943322097478
Author(s):  
Song Li ◽  
Chu-Jie Jiao
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Local Buckling ◽  
Steel Tube ◽  
Experimental Results ◽  
Reactive Powder Concrete ◽  
Test Results ◽  
Steel Tubes ◽  
Reactive Powder ◽  
Concrete Filled Steel Tubes

Reactive powder concrete-filled steel tubes (RPCFSTs) have become an important research target in recent years. In engineering applications, RPCFSTs can provide superior vertical components for high-rise and tower buildings, thereby enabling developers to provide more floor space. However, this type of composite structure is prone to inelastic outward local buckling. The use of carbon fiber reinforced polymer (CFRP) wrapping to suppress such local buckling has shown great potential in limited test results. This paper presents experimental results concerning the axial compression of CFRP-confined reactive powder concrete-filled circular steel tubes (CF-RPCFSTs). We included 18 specimens in our experimental investigation, varying the number of CFRP layers, steel tube thickness, and RPC strength. According to our test results, CF-RPCFSTs exhibit compression shear failure and drum-shaped failure. The CFRP wrap can effectively enhance bearing capacity and postpone local buckling of the steel tube. In addition, three-layer CFRP-confined RPC-filled thin-wall steel tubes are suitable for engineering. We also propose a model to calculate the bearing capacity of CF-RPCFSTs. Compared to the existing model of CFRP-confined concrete-filled steel tubes, the results obtained using the proposed model are in good agreement with our experimental results.

Study of Post-Fire Bearing Capacity of Self-Stress Ceramsite Concrete Filled Steel Tubes

2012 ◽  
Vol 204-208 ◽  
pp. 3222-3225
Author(s):  
Jian Min Wang ◽  
Jinyi Zhang ◽  
Xin Tang Wang ◽  
Hong Liang Sun
Keyword(s):  
Mechanical Behavior ◽  
Bearing Capacity ◽  
Experimental Results ◽  
Furnace Temperature ◽  
Steel Tubes ◽  
Short Columns ◽  
Concrete Filled Steel Tubes

Mechanical behavior and bearing capacity of self stress ceramsite concrete filled steel tubes (noted as SCCST) after exposure to fire are experimentally studied. Effect of the parameters, such as value of furnace temperatures, self stress on the post-fire bearing capacity and ductility of the specimens after exposure to fire were especially discussed. The experimental results show that all the specimens of SCCST have higher post-fire bearing capacity and better ductility, and there was no obvious descending segment in the load-strain curves of the most specimens after exposure to fire. It was concluded that the furnace temperature subjected to the specimens and the initial self stress produced in the specimens of the composite short columns has some effect on the axial bearing capacity of ceramsite concrete-filled steel tubular short columns after exposure to fire, and the volume of expansion agent of 10% has most great effect on post-fire bearing capacity of SCCST after exposure to fire.

scholarly journals Early-Age Tensile Bond Characteristics of Epoxy Coatings for Underwater Applications

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 757 ◽  
Author(s):  
Kim ◽  
Hong ◽  
Han ◽  
Kim
Keyword(s):  
Bond Strength ◽  
Surface Treatment ◽  
Epoxy Resin ◽  
Coating Thickness ◽  
Experimental Results ◽  
Early Age ◽  
Curing Time ◽  
Bond Performance ◽  
Coating Type ◽  
Bond Characteristics

In this study, coating equipment for the effective underwater repair of submerged structures was developed. The tensile bond characteristics of selected epoxy resin coatings were investigated by coating the surface of a specimen using each of the four types of equipment. Using the experimental results, the tensile bond strength and the coating thickness were analyzed according to the type of equipment, coating, and curing time. The results show that the type of coating equipment used had the greatest effect on the measured bond strength and coating thickness of the selected coatings. However, the effect of coating type and curing time on the bond strength and the thickness was observed to be insignificant. Compared with the developed equipment, the surface treatment of the coating was observed to be more effective when using the pre-existing equipment, and thus the bond performance of the coating was improved compared to using the pre-existing equipment. Based on the experimental results, improvements and needs involving the equipment for further research were discussed.

Bond properties of steel angles in concrete filled steel tubes

2021 ◽  
Vol 182 ◽  
pp. 106653
Author(s):  
Da-wei Zhang ◽  
Yu Zeng ◽  
Ju Chen ◽  
Fuyuan Gong ◽  
Cheng-bin Liu
Keyword(s):  
Bond Properties ◽  
Steel Tubes ◽  
Steel Angles ◽  
Concrete Filled Steel Tubes
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