Experimental Study on In-Plane Behavior of CFST Arch with New-Type Dumbbell-Shaped Section

2011 ◽  
Vol 255-260 ◽  
pp. 1198-1203 ◽  
Author(s):  
Ye Sheng
Keyword(s):  
Local Buckling ◽  
High Strength ◽  
Steel Tube ◽  
Calculation Model ◽  
Plastic Behavior ◽  
Loading Process ◽  
New Type ◽  
Set Up ◽  
Ultimate Load Carrying Capacity ◽  
Shaped Section

The weakness of traditional dumbbell-shaped section is that when concrete is filled into the web space, great stress is likely to produce cracks in the weld sealing between steel tube and web plates. In order to avoid this condition, a new-type dumbbell-shaped section is proposed. Experiments on concrete filled steel tubular (CFST) model arches with new-type dumbbell-shaped section have been carried out, concentrated loading at crown and L/4 section respectively. The result indicated that the new-type CFST arch has good elastic-plastic behavior and high strength, no local buckling appeared during the whole loading process, its in-plane mechanic behavior is similar with that of the CFST arch with single-tube. The dual nonlinear finite element calculation model is set up for the model arch, by means of this model the load-deflection curves during the loading process and the ultimate load-carrying capacity is analyzed.

Structural Performance of High Strength Concrete Filled Steel Tube with the Width-to-Thickness Ratio

2013 ◽  
Vol 284-287 ◽  
pp. 1390-1395
Author(s):  
Geon Ho Hong ◽  
Won Ki Kim ◽  
In Rak Choi ◽  
Kyung Soo Chung
Keyword(s):  
High Strength Steel ◽  
Local Buckling ◽  
Tall Buildings ◽  
High Strength ◽  
Steel Tube ◽  
Thickness Ratio ◽  
Maximum Strength ◽  
Structural Performance ◽  
Deformation Capacity ◽  
Concrete Filled Steel Tube

Concrete filled steel tube has been consistently used in tall buildings as it represents excellent structural performance and economical efficiency compared with other structural systems. The use of high strength steel in concrete filled steel tube can reduce the column size and increase the effective space in the buildings. But, the limit of width-to-thickness ratio to prevent local buckling is an obstacle to applying the high strength steel as it considerably decrease following to the strength increase. This paper addresses the effect of steel plate slenderness limit on the compression behavior in 800 MPa Grade steel. Four short column specimens were tested under axial compression. Main test variables were width-to-thickness ratio and shape of section. Test results were analyzed in the viewpoint of local buckling strength, yield strength, maximum strength and plastic deformation capacity of specimens. The experimental results showed that all specimens exceeded the maximum strength of calculated value by design code and represented similar deformation capacity regardless of width-to-thickness ratio. So, the limit of width-to-thickness ratio in high strength steel could be amended less strict.

Research on the Bearing Capacity of High-Strength Steel Tubular H-Joints in High-Voltage Transmission Lines

2014 ◽  
Vol 513-517 ◽  
pp. 4123-4126 ◽  
Author(s):  
Yun Xu
Keyword(s):  
Bearing Capacity ◽  
Transmission Lines ◽  
Local Buckling ◽  
Bending Moment ◽  
High Strength ◽  
Steel Tube ◽  
Scale Model ◽  
Tube Plate ◽  
Control Factors ◽  
Local Strength

The steel tube-plate joints are widely applied in tall-slender tower of transmission line engineering,but there are few studies at home and abroad. In this paper,experimental study with full-scale model and analysis based on FEM were carried out on the ultimate bearing capacity of typical h-joints , and the results showed that the bending moment was transferred to the chord from the ear-plate of a narrow area, which led to local buckling on the chord wall , so the local strength of chord is one of the most important control factors in the design of this typical joint;thus the bearing capacity can improve by enhancing the strength of steel or increasing the thickness of ear-plate. In view of the phenomenon that stress concentration is easy to emerge at the intersection of the steel tube-plate joints, some improvement measures for the connections are put forward,such as adding outer half-ring stiffening plates , adding outer-ring plates , adding inner-ring plates, and revising ear-plates to smooth the concave angle , etc.

Research on Machanical Behavior of T-Shaped Concrete-Filled Steel Tubular Stub Columns with Steel Bone

2013 ◽  
Vol 639-640 ◽  
pp. 1077-1082
Author(s):  
Kai Lin Ju ◽  
Qiu Sheng Li ◽  
Guo Feng Du ◽  
Yi Li
Keyword(s):  
Local Buckling ◽  
Steel Tube ◽  
Experimental Results ◽  
Concrete Core ◽  
Concrete Filled Steel Tube ◽  
Tubular Columns ◽  
Calculation Results ◽  
New Type ◽  
Stub Columns ◽  
Tube Structure

Concrete-filled steel tube structure is one of the important load-bearing systems of modern high-rise building.The research indicate that concrete-filled steel tube structure has a good static and seismic performance,and concrete-filled steel tubular component is always used as axial compression and compression-bending component.However,what about the mechanical behavior of this combinational structure (concrete-filled steel tubular columns with steel bone built-in)? So there is a new type of special-shaped cross-section of composite structure,that is the T-shaped concrete-filled steel tubular columns with steel bone.The research about this structure is less throughout domestic and foreign.So the axial compressive experiments of six T-shaped concrete-filled steel tubular stub columns, five with and one without steel bone, were carried out. The effects of tube confining factor, bone indicator on the axial compressive behavior of the columns are analyzed. Experimental results indicate that the ultimate strength of the T-shaped steel tubular stub columns with steel bone increases, can be increased by 71.7%.And that the setting of steel bone improves the confinement of the concrete core, delays or even avoids the local buckling of the steel tube before the stress attains the yield strength. The ductility of the columns is also greatly increased.And at last in this paper, use of static equilibrium conditions and limit yield conditions,and in reference to literature[1],the calculation equation of compression capacity of this combinational column is derived.Moreover,calculation results according to the formula in this paper are in good agreement with the experimental results. The conclusions might be used as reference to structural design and plan.

Summary of Performance and the Application of the Concrete Filled Steel Tubular Structures

2013 ◽  
Vol 834-836 ◽  
pp. 693-696
Author(s):  
Jing Gong ◽  
Jia Li ◽  
Yue Tang ◽  
Yuan Miao
Keyword(s):  
Composite Material ◽  
Bearing Capacity ◽  
Detailed Analysis ◽  
Local Buckling ◽  
Steel Tube ◽  
Tubular Structures ◽  
Advantages And Disadvantages ◽  
New Type ◽  
Summary Of Performance ◽  
Tubular Components

Due to the restraint of steel tube concrete of concrete filled steel tubular components，three directions’ compression at the same time， the bearing capacity of concrete is obviously improved.As a result of the existence of steel pipe concrete，can effectively prevent the steel tube of local buckling ，com-plementary advantages and disadvantages of these two kinds of material ， the performance of the material is greatly improved. In this paper, the performance and characteristics of the composite material has carried on the detailed instructions，the ultimate bearing capacity of calculation principle has carried on the detailed analysis and research， the application of this new type of material are summarized.

Parameter Analysis on Ultimate Load-Carrying Capacity of CFST Arch Rib with New-Type Dumbbell-Shaped Section

2013 ◽  
Vol 634-638 ◽  
pp. 3825-3829
Author(s):  
Ye Sheng
Keyword(s):  
Carrying Capacity ◽  
Ultimate Load ◽  
Slenderness Ratio ◽  
Research Work ◽  
Parameter Analysis ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
New Type ◽  
Ultimate Load Carrying Capacity ◽  
Shaped Section

Experiments on concrete filled steel tubular (CFST) model arches with new-type dumbbell-shaped section have been carried out, concentrated loading at crown and L/4 section respectively. Applied with large general program ANSYS, a finite element calculation model was set up for the model arch, by means of this model the main parameters including arch axis coefficient, ratio of rise to span, slenderness ratio, and steel ratio are analyzed. Based on the discussion of influence of parameter variation on nonlinear characteristics and ultimate load-carrying capacity of model arch, the theoretical basis is established for the development of this structure and the conclusion can be taken as reference in practice use and further research work.

scholarly journals Experimental study on seismic behavior of full scale square concrete filled steel tubular stocky columns

2021 ◽  
Vol 272 ◽  
pp. 02024
Author(s):  
Jin Liu ◽  
Liang Jian ◽  
Du Xiuli
Keyword(s):  
Shear Failure ◽  
Plastic Hinge ◽  
Local Buckling ◽  
Steel Tube ◽  
Calculation Model ◽  
Full Scale ◽  
Cross Sectional ◽  
Short Columns ◽  
Cfst Columns ◽  
Plastic Hinge Length

This study mainly presented a pseudo-static experiment on two full-scale square CFST short columns with the cross-sectional width of 600 mm under combined constant axial load and cyclic lateral load. The seismic performance of the two full-scale CFST columns were investigated. Meanwhile, the plastic hinge length of the specimens was discussed. The test results presented that the specimens suffered bend-shear failure. The local buckling of steel tube occurred at the end of the specimens and the core concrete crushed. The safety redundancy of lateral bearing capacity decreased in full-scale specimen. By the method of physical observation, the plastic hinge length Lp1 was determined mainly according to the range of the local buckling of steel tube. There had a great difference between the prediction of plastic hinge lengths by the existing calculation model and the plastic hinge lengths obtained by the test.

Elastic Analysis on Post-Local Buckling of Steel Plates in Thin-Walled Rectangular Concrete-Filled Steel Tube Columns

2012 ◽  
Vol 204-208 ◽  
pp. 912-916
Author(s):  
Shao Chun Guo ◽  
Hai Feng Liu
Keyword(s):  
Local Buckling ◽  
Local Stress ◽  
High Strength ◽  
Steel Tube ◽  
Steel Plates ◽  
Thin Wall ◽  
Concrete Filled Steel Tube ◽  
Buckling Behavior ◽  
Large Width ◽  
Deflection Theory

With the wide application of high-strength concrete and thin-wall steel tube in concrete-filled steel tube, it is essential to study the post-local buckling behavior of rectangle steel plates. Based on large deflection theory of plate, the post-local buckling behavior of steel plates in concrete-filled steel tube is analyzed in this paper. At the same time, the post-local stress of steel plates is obtained. The results indicate that the post-local buckling behavior of steel plates can be effectively utilized in large width-to-thickness ratios of steel plates.

Preliminary Investigation on the Flexural Behaviour of Steel Fibre Reinforced Self-Compacting Concrete Ribbed Slab

2018 ◽  
Vol 15 (1) ◽  
pp. 31
Author(s):  
Nur Aiman Suparlan ◽  
Muhammad Azrul Ku Ayob ◽  
Hazrina Ahmad ◽  
Siti Hawa Hamzah ◽  
Mohd Hisbany Mohd Hashim
Keyword(s):  
Ultimate Load ◽  
Steel Fibre ◽  
Preliminary Investigation ◽  
Bending Test ◽  
Flexural Behaviour ◽  
Self Compacting Concrete ◽  
Two Samples ◽  
Simple Support ◽  
Set Up ◽  
Ultimate Load Carrying Capacity

A ribbed slab structure has the advantage in the reduction of concrete volume in between the ribs resulting in a lower structural self-weight. In order to overcome the drawbacks in the construction process, the application of steel fibre self-compacting concrete (SCFRC) is seen as an alternative material to be used in the slab. This preliminary investigation was carried out to investigate the flexural behaviour of steel fibre self-compacting concrete (SCFRC) as the main material in ribbed slab omitting the conventional reinforcements. Two samples of ribbed slab were prepared for this preliminary study; 2-ribbed and 3-ribbed in 1 m width to identify the effect of the geometry to the slab’s flexural behaviour. The dimension of both samples is 2.5 m x 1 m with 150 mm thickness. The compressive strength of the mix is 48.6 MPa based on the cubes tested at 28 days. Load was applied to failure by using the four point bending test set-up with simple support condition. The result of the experiment recorded ultimate load carrying capacity at 30.68 kN for the 2-ribbed slab and 25.52 kN for 3-ribbed slab. From the results, the ultimate load of the 2-ribbed sample exceeds 3-ribbed by approximately 20%. This proved that even with lower concrete volume, the sample can still withstand an almost similar ultimate load. Cracks was also observed and recorded with the maximum crack width of 2 mm. It can be concluded that the steel fibres do have the potential to withstand flexural loadings. Steel fibre reduces macro-crack forming into micro-cracks and improves concrete ductility, as well as improvement in deflection. This shows that steel fibre reinforced self-compacting concrete is practical as it offers good concrete properties as well as it can be mixed, placed easier without compaction. 

scholarly journals Calculation Model for the Mixing Amount of Internal Curing Materials in High-strength Concrete based on Modified MULTIMOORA

2020 ◽  
Vol 27 (1) ◽  
pp. 455-463
Author(s):  
Lixia Guo ◽  
Minghua Wang ◽  
Ling Zhong ◽  
Yanan Zhang
Keyword(s):  
High Strength Concrete ◽  
High Strength ◽  
Calculation Model ◽  
Internal Curing ◽  
Total Water ◽  
Water Release ◽  
Strength Concrete ◽  
Numerical Example ◽  
Comprehensive Performance ◽  
Mixing Method

AbstractThe internal curing technology has been widely applied to high-strength concrete, for it can make the high-strength concrete marked by low shrinkage and durable frost resistance. The key to its extension and application lies in the reasonable mixing amount of internal curing materials. To address this problem, scholars have proposed a method for determining the water demand in internal curing; however, the water release of internal curing materials is difficult to obtain by measurement due to the mixing method. Therefore, this paper proposed a calculation model for the mixing amount of internal curing materials based on the modified MULTIMOORA method (Multi-Objective Optimization on the basis of Ratio Analysis plus full multiplicative form). First, different internal curing materials (super absorbent polymer (SAP), lightweight aggregate (LWA)) and pretreatment methods were selected to calculate their compressive strength, self-shrinkage and frost durability according to a proposed test scheme on the mixing amount of internal curing materials, and in such case, the comprehensive performance evaluation of the above indexes was turned into a multi-attribute decision-making problem. Second, the ordered weighted averaging (OWA) method and the entropy weight method were used to determine the subjective and objective weights of the indexes respectively, to eliminate the impact of outliers in the subjective evaluation values. Finally, the comprehensive performance of each test group was sorted using MULTIMOORA, and based on the sorting results and the calculation model, the mixing amount of internal curing materials was determined. The numerical example application results showed that the mixing amount of SAP curing material calculated based on the model herein was 1.276 kg/m3, and the mixing method adopted the pre-water absorption method with the total water-binder ratio unchanged. The numerical example evaluation results were in good agreement with the test results. The internal curing effect of SAP was better than that of LWA, and reached the best when the mixing amount was calculated at 25 times the water release rate and the requirement for the maximum total water diversion was met. The study may provide new ideas for extension and application of the internal curing technology.

Evaluation of a personal professional mentor scheme for newly qualified nurses

2021 ◽  
Vol 30 (11) ◽  
pp. 672-676
Author(s):  
Charlotte Austin ◽  
Yvonne Halpin
Keyword(s):  
Thematic Analysis ◽  
Structured Interview ◽  
Potential Outcomes ◽  
Experienced Nurses ◽  
Support Strategies ◽  
Supportive Role ◽  
New Type ◽  
Experienced Nurse ◽  
Set Up ◽  
Pastoral Support

Background: Newly qualified nurses are known to experience a range of feelings and fears in the first transitional 12 months post-qualifying, with absence and turnover among potential outcomes. Aim: To evaluate the personal professional mentor role and scheme, a new pastoral support initiative, from the perspective of participating newly qualified nurses. Methods: Newly qualified paediatric nurses (n=10), who had been assigned a personal professional mentor (an experienced nurse who worked elsewhere in their employing NHS Trust), completed a semi-structured interview. The data were analysed using thematic analysis. Findings: The personal professional mentor counteracted some aspects of transition isolation for the newly qualified nurses. They were an independent, accessible, experienced confidant and a welcome new supportive role. Conclusion: Pairing experienced nurses with newly qualified nurses provided a new type of workplace support during transition. Inexpensive to set up and run, it is an easy addition to any portfolio of support strategies.

Sign in / Sign up

Export Citation Format

Share Document