Strength predictions of circular hollow section T-joints of steel grade 1100 MPa

2022 ◽  
Vol 188 ◽  
pp. 107003
Author(s):  
Yancheng Cai ◽  
Tak-Ming Chan ◽  
Ben Young
Keyword(s):  
Steel Grade ◽  
T Joints ◽  
Hollow Section ◽  
Circular Hollow Section

Axial strength of steel circular hollow section (CHS) X-joints strengthened by flanged larger pipe

2020 ◽  
Vol 47 (3) ◽  
pp. 301-316
Author(s):  
Peter Gerges ◽  
Sameh Gaawan ◽  
Ashraf Osman
Keyword(s):  
Finite Element ◽  
Parametric Study ◽  
Thickness Ratio ◽  
Finite Element Models ◽  
T Joints ◽  
Hollow Section ◽  
Axial Strength ◽  
Structural Joints ◽  
Circular Hollow Section ◽  
Steel Design

In steel design, enhancing the structural joints’ capacity is considered a challenge that faces the designer. This challenge becomes more difficult when it comes to enhancing the capacities of circular hollow section (CHS) joints due to their closed nature that complicates the strengthening process. Recent research related to strengthening T-joints by utilizing two outer hollow ring flanges welded to additional pipe showed that this technique can significantly improve the joints’ strength. In this study, the utilization of this technique is extended for enhancing the axial strength of CHS X-joints. In this regard, a parametric study using finite element models was carried out to investigate the different design aspects that might affect the behavior of strengthened X-joints. The examined parameters included, the ring flange diameter, the stiffening pipe thickness and length for different brace diameter-to-chord diameter ratios and chord diameter to double chord thickness ratio. The results demonstrated that these strengthened X-joints gained significant axial strength that reached up to three times the axial strength of the unstrengthened joints. Guidelines for proper detailing of such strengthening scheme were provided. Finally, an equation that estimates the axial strength of strengthened joints was established based on the achieved results.

scholarly journals Confining T-joints by adding two outer hollow ring flanges welded to additional hollow circular pipe

2017 ◽  
Vol 44 (10) ◽  
pp. 783-801 ◽  
Author(s):  
Peter Gerges Melek ◽  
Mohamed Hussein ◽  
Sameh Gaawan
Keyword(s):  
Parametric Study ◽  
Diameter Ratio ◽  
Outer Ring ◽  
Circular Pipe ◽  
Compression Force ◽  
T Joints ◽  
Hollow Section ◽  
Joint Location ◽  
Circular Hollow Section ◽  
Strengthening Technique

Increasing the capacity of circular hollow section (CHS) T-joints is a challenge for the designers due to its closed nature that makes strengthening difficult as the traditional strengthening techniques focus on adding ring stiffeners inside the chord, these techniques require splitting the chord at each joint location into more than one part and this is not applicable for stiffening prefabricated and erected T-joints. This paper presents a proposed strengthening technique that is based on confining the T-joint by two outer hollow ring flanges welded to additional hollow circular pipe. A parametric study is carried out to investigate the effect of the hollow ring flanges diameter, the added elements thickness, and the spacing between the hollow outer ring flanges on increasing the capacity of T-joints for different values of β (db/d0: brace diameter-to-chord diameter ratio) when the brace is either subjected to tension or compression force. Finally, it is observed that the compressive T-joints gain up to 267% of its original capacity and the tensile T-joints gain up to 65% of its original capacity.

Discussion on two methods for determining static strength of tubular T-joints at elevated temperature

2016 ◽  
Vol 20 (5) ◽  
pp. 704-721 ◽  
Author(s):  
Yongbo Shao ◽  
Haicheng Zhao ◽  
Dongping Yang
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Elevated Temperature ◽  
Critical Temperature ◽  
Mechanical Analysis ◽  
Static Strength ◽  
T Joints ◽  
Hollow Section ◽  
Tubular Joint ◽  
Circular Hollow Section

To predict the static strength of a welded tubular joint at elevated temperature using finite element simulation, two methods in the literature were reported. The first method aims to analyze the static strength of a tubular joint at a specified elevated temperature, and a routine mechanical analysis is carried out by defining the material properties at the specified elevated temperature according to some specifications. This method does not consider the heat transfer process of the tubular joint in a fire condition. The second method is used to determine the static strength of a tubular joint using a combination of transient state heat transfer analysis and mechanical analysis. The tubular joint subjected to a specified load is heated in accordance with ISO 834-1 standard fire curve to fail at a critical temperature, and the specified load is considered as the static strength of the joint at the critical temperature. In this study, a detailed parametric study on the failure process of circular hollow section tubular T-joints at elevated temperature is carried out using finite element method. The static strengths of the circular hollow section T-joint models obtained from the two methods are compared. The comparison shows that the first method produces a higher estimation on the static strength compared to the second method. Finally, the effect of some geometrical parameters, chord stress ratio, and elevated temperature on the difference of the two methods is also investigated.

Axial capacity of circular hollow section T-joints using grade HSB 600 steel

2012 ◽  
Vol 12 (4) ◽  
pp. 483-494 ◽  
Author(s):  
Byong-Jeong Choi ◽  
Eun-Taik Lee ◽  
Jae-Guen Yang ◽  
Cheol-Kyu Kang
Keyword(s):  
T Joints ◽  
Hollow Section ◽  
Axial Capacity ◽  
Circular Hollow Section

Experimental Study on SNCF of Welded CHS-CFSHS T-Joints under Axial Loading

2010 ◽  
Vol 163-167 ◽  
pp. 127-131
Author(s):  
De Lei Yang ◽  
Le Wei Tong ◽  
Xiao Lin Zhao
Keyword(s):  
Experimental Study ◽  
Axial Loading ◽  
T Joints ◽  
Strain Concentration ◽  
Hollow Section ◽  
Lower Strain ◽  
Tension And Compression ◽  
Concentration Factors ◽  
Intersection Line ◽  
Circular Hollow Section

The initiation position can be predicted by studying on strain concentration factors (SNCF) and SNCF distributions. This paper concerns an experimental investigation of SNCF of welded T-joints composed of circular hollow section (CHS) braces and concrete-filled square hollow section (CFSHS) chords under axial loading on the braces with two load cases of tension and compression. Static experiments were performed on eight test specimens designed for considering different non-dimensional geometric parameters and C50 grade concrete. Compared with joints made of CHS-SHS, the experimental results indicate that the CHS-CFSHS T-joints have lower strain concentration factors which may increase fatigue strength. The position of the maximum SNCF is usually located at 00 or 900 of the intersection line between a CHS brace and a CFSHS chord.

scholarly journals Buckling Behavior of Non-Retrofitted and FRP-Retrofitted Steel CHS T-Joints

2021 ◽  
Vol 11 (7) ◽  
pp. 3098
Author(s):  
Amin Yazdi ◽  
Maria Rashidi ◽  
Mohammad Alembagheri ◽  
Bijan Samali
Keyword(s):  
Compressive Loading ◽  
Local Buckling ◽  
Buckling Mode ◽  
T Joints ◽  
Hollow Section ◽  
Frp Composite ◽  
Buckling Behavior ◽  
Global Buckling ◽  
Post Buckling ◽  
Circular Hollow Section

This paper aims to investigate the buckling behavior of circular hollow section (CHS) T-joints in retrofitted and non-retrofitted states under axial brace compressive loading. For this purpose, two types of analysis are carried out. The first one is evaluating the critical buckling load in various tubular joints, and the other one is investigating the post-buckling behavior after each buckling mode. More than 180 CHS T-joints with various normalized geometric properties were numerically modeled in non-retrofitted state to compute their governing buckling mode, i.e., chord ovalization, brace local, or global buckling. Then three joints with different buckling modes were selected to be retrofitted by fiber-reinforced polymer (FRP) patches to illustrate the improving effect of the FRP wrapping on the post-buckling performance of the retrofitted joints. In addition, FRP composite failures were investigated. The results indicate that the FRP retrofitting is able to prevent the brace local buckling, and that matrix failure is the most common composite failure in the retrofitted joints.

Finite Element Validation Studies of BS7910 FAD Method Applied to Welded SHS Joints

2007 ◽  
Author(s):  
Zhengmao Yang ◽  
Seng Tjhen Lie ◽  
Wie Min Gho
Keyword(s):  
Finite Element ◽  
Offshore Structures ◽  
Reduction Factor ◽  
Plastic Collapse ◽  
Surface Cracks ◽  
Collapse Load ◽  
T Joints ◽  
Hollow Section ◽  
Wide Range ◽  
Circular Hollow Section

The failure assessment diagram (FAD) has now been widely accepted and used for the assessment of defects found in metallic structures. In BS7910 (2005), the use of this method for offshore structures has been validated for a range of joint geometries. But these validations are only applicable for circular hollow section (CHS) welded joints. For rectangular or square hollow section (RHS or SHS) joints, there are very few references available in the literature. In this paper, systematic investigations have been carried out for the validation and verification of the FAD curves for SHS T-joints. FAD curves for a wide range of welded SHS T-joints containing surface cracks have been established using the fracture mechanics data generated from the finite element analyses. The range of β ratio of these joints is from 0.3 to 0.8. Therefore, the failure mode is constrained in the chord face yielding. The influence of residual stresses on the plastic collapse load and the FAD curves has also been analyzed. The reduction factor used to calculate the plastic collapse load of the SHS T-joints containing cracks have been quantitatively examined, and the use of the BS7910 (2005) Level 2A FAD for SHS joints containing surface cracks has been validated accordingly.

scholarly journals Durability of CFRP strengthened steel circular hollow section member exposed to sea water

2016 ◽  
Vol 118 ◽  
pp. 216-225 ◽  
Author(s):  
M.H. Kabir ◽  
S. Fawzia ◽  
T.H.T. Chan ◽  
M. Badawi
Keyword(s):  
Sea Water ◽  
Hollow Section ◽  
Circular Hollow Section
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