scholarly journals Distortional buckling behavior and design method of cold-formed steel lipped channel with rectangular holes under axial compression

2021 ◽  
Vol 18 (5) ◽  
pp. 6239-6261
Author(s):  
Yanli Guo ◽  
◽  
Xingyou Yao ◽  
Keyword(s):  
Parametric Study ◽  
Design Method ◽  
Fe Model ◽  
Building Structures ◽  
Test Results ◽  
Distortional Buckling ◽  
Comparison Results ◽  
Study Results ◽  
Load Carrying ◽  
Cold Formed Steel

<abstract> <p>The use of cold-formed steel (CFS) channel sections with rectangular holes in the web is becoming gradually popular in building structures. However, such holes can result in sections becoming more susceptible to be distortional buckling and display lower load-carrying capacities. This paper presents a total of 44 axially-compressed tests of CFS lipped channel columns with and without rectangular web holes including different hole sizes and cross-sections. The test results show that the specimens were controlled by distortional buckling or interaction of local buckling and distortional buckling. The load-carrying capacities of specimens with rectangular holes were lower than that of specimens without hole. The load-carrying capacities of specimens were gradually decreased with the increasing of dimensions of holes. Then a nonlinear elasto-plastic finite element model (FEM) was developed and the analysis results showed good agreement with the test results. The validated FE model was used to conduct a parametric study involving 16 FEM to investigate the effects of the section, the dimension of the hole, and the number of holes on the ultimate strength of such channels. Furthermore, the formulas to predict the distortional buckling coefficient were developed for the section with holes by using the verified FEM. Finally, the tests and parametric study results were compared against the distortional buckling design strengths calculated in accordance with the developed method. The comparison results show that the proposed design method closely predict the load carrying capacity of CFS channel sections with rectangular web holes.</p> </abstract>

scholarly journals Experimental Investigation and Load Capacity of Slender Cold-Formed Lipped Channel Sections with Holes in Compression

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Xingyou Yao
Keyword(s):  
Parametric Study ◽  
Load Capacity ◽  
Fe Model ◽  
Building Structures ◽  
Test Results ◽  
Compression Tests ◽  
Axial Strength ◽  
Comparison Results ◽  
Study Results ◽  
Global Buckling

The use of cold-formed steel (CFS) channels with circular or rectangular web holes is becoming increasingly popular in building structures. However, such holes can result in sections becoming more susceptible to buckle and display lower load-carrying capacities. This paper presents a total of 42 axial compression tests of CFS lipped channel slender columns with and without circular and rectangular web holes, including different hole sizes and cross sections. The test results show that the axial members with a small ratio of width to thickness were governed by global buckling, while the members with a large ratio of width to thickness were controlled by the interaction of local, distortional, and global buckling. The axial strength decreased maximum by 20.48% and 22.98% for the member with circular holes and rectangular holes, compared to a member without a web hole. Then, a nonlinear elastoplastic finite element model (FEM) was developed, and the analysis results showed good agreement with the test results. The validated FE model was used to conduct a parametric study involving 36 FEMs to investigate the effects of column slenderness, dimension of the hole, and the number of holes on the axial strength of such channels. Furthermore, the formulas to predict the global buckling coefficient and the effective area were modified for such sections with holes by using the verified FEM. Finally, the tests and parametric study results were compared against the design strengths calculated in accordance with the developed method. The comparison results show that the proposed design method closely predicts the axial capacity of CFS channels with circular or rectangular web holes.

scholarly journals Experiment and Design Method on Cold-Formed Thin-Walled Steel Lipped Channel Columns with Slotted Web Holes Under Axial Compression

2017 ◽  
Vol 11 (1) ◽  
pp. 244-257 ◽  
Author(s):  
Xingyou Yao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Ultimate Strength ◽  
Test Results ◽  
Distortional Buckling ◽  
Steel Columns ◽  
Cold Formed Steel ◽  
Thin Walled ◽  
Shell Finite Element ◽  
The Web

Background: Cold-formed steel structural sections used in the walls of residential buildings and agricultural facilities are commonly C-shaped sections with web holes. These holes located in the web of sections can alter the elastic stiffness and the ultimate strength of a structural member. The objective of this paper is to study the buckling mode and load-carrying capacity of cold-formed thin-walled steel column with slotted web holes. Methods: Compression tests were conducted on 26 intermediate length columns with and without holes. The tested compressive members included four different kinds of holes. For each specimen, a shell finite element Eigen-buckling analysis and nonlinear analysis were also conducted. The influence of the slotted web hole on local and distortional buckling response had also been studied. The comparison on ultimate strength between test results and calculated results using Chinese cold-formed steel specification GB50018-2002, North American cold-formed steel specification AISI S100-2016, and nonlinear Finite Element method was made. Result: Test results showed that the distortional buckling occurred for intermediate columns with slotted holes and the ultimate strength of columns with holes was less than that of columns without holes. The ultimate strength of columns decreased with the increase in transverse width of hole in the cross-section of member. The Finite element analysis results showed that the web holes could influence on the elastic buckling stress of columns. The shell finite element could be used to model the buckling modes and analysis the ultimate strength of members with slotted web holes. The calculated ultimate strength shows that results predicted with AISI S100-2016 and analyzed using finite element method are close to test results. The calculated results using Chinese code are higher than the test results because Chinese code has no provision to calculate the ultimate strength of members with slotted web holes. Conclusion: The calculated method for cold-formed thin-walled steel columns with slotted web holes are proposed based on effective width method in Chinese code. The results calculated using the proposed method show good agreement with test results and can be used in engineering design for some specific cold-formed steel columns with slotted web holes studied in this paper.

Member distortional buckling behaviour of hybrid double-I-box beams

2018 ◽  
Vol 45 (8) ◽  
pp. 605-622 ◽  
Author(s):  
M.S. Deepak ◽  
V.M. Shanthi
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Parametric Study ◽  
Flexural Rigidity ◽  
Numerical Study ◽  
Plate Thickness ◽  
Distortional Buckling ◽  
Study Results ◽  
Box Beams ◽  
The Moment

This paper compiles the experimental and finite-element parametric study on member distortional buckling behaviour of new built-up metal hybrid double-I-box beams (HDIBBs). The cross-section of this built-up beam is unique and looks similar to the shape of a double-I-box fabricated using four channel sections. The flange plates were provided with an intermediate stiffener. In these built-up beams there is more material in the flange portions far away from the horizontal centroidal axis of their cross-section. Hence, there is an increase in the flexural rigidity that enhances the moment capacity of the beam, under major axis bending. The geometry consists of torsionally rigid closed-box web portion that provides high resistance to minor axis lateral-buckling. The varying parameters considered were the ratio of yield stresses of the flange to the web steel plates, the ratio of breadth to the depth of the section, and the flange plate thickness. In the experimental programme, all the HDIBB members failed due to kinds of distortional buckling which was identified by web buckling and flange twist along edges. The results revealed that when flange plate slenderness increases there is a drop in the moment resistance capacity of the beams. The numerical study was performed using ABAQUS software. In comparison, there was good agreement between experimental and numerical results. The validated finite element models were further extended to perform parametric studies on ideal HDIBB models. Both the experimental and parametric study results were compared with the predicted strengths using effective width method equations specified in the Euro code standards EN 3-1-3. It was found that the current Euro code design rules slightly over-estimate the distortional buckling resistance capacity of closed form built-up cold-formed steel members. A new design equation was formulated and recommended for estimating the reduction in distortional buckling moment resistance capacity for HDIBBs.

scholarly journals Behavior of an Advanced Bolted Shear Connector in Prefabricated Steel-Concrete Composite Beams

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2958 ◽  
Author(s):  
Jun Chen ◽  
Wei Wang ◽  
Fa-Xing Ding ◽  
Ping Xiang ◽  
Yu-Jie Yu ◽  
...  
Keyword(s):  
Composite Structures ◽  
Concrete Slab ◽  
Concrete Strength ◽  
High Strength ◽  
Fe Model ◽  
Building Structures ◽  
Shear Connector ◽  
Test Results ◽  
Shear Connectors ◽  
Bolt Pretension

The high-strength bolt shear connector in prefabricated concrete slab has advantages in applications as it reduces time during the construction of steel-concrete composite building structures and bridges. In this research, an innovative and advanced bolt shear connector in steel-concrete composite structures is proposed. To investigate the fundamental mechanical behavior and the damage form, 22 static push-off tests were conducted with consideration of different bolt dimensions, the reserved hole constraint condition, and the dimension of slab holes. A finite element (FE) model was established and verified by using test results, and then the model was utilized to investigate the influence of concrete strength, bolt dimension, yield strength, bolt pretension, as well as length-to-diameter ratio of high strength bolts on the performances of shear connectors. On the basis of FE simulation and test results, new design formulas for the calculation of shear resistance behavior were proposed, and comparisons were made with current standards, including AISC, EN 1994-1-1, GB 50017-2017, and relevant references, to check the calculation efficiency. It is confirmed that the proposed equation is in better agreement with the experimental results.

scholarly journals Experimental Study and Direct Strength Method for Cold-Formed Steel Built-Up I-Sectional Columns under Axial Compression

2021 ◽  
Vol 2021 ◽  
pp. 1-22
Author(s):  
Xingyou Yao
Keyword(s):  
Finite Element ◽  
Axial Compression ◽  
Numerical Study ◽  
Experimental Results ◽  
Distortional Buckling ◽  
Cross Sectional ◽  
Direct Strength Method ◽  
Comparison Results ◽  
Cold Formed Steel ◽  
Interactive Buckling

The objective of this paper is to investigate the buckling behavior and design method of the ultimate strength for the cold-formed steel (CFS) built-up I-sectional columns under axial compression which failed in distortional buckling and interactive buckling. A total of 56 CFS built-up I-sectional columns subjected to axial compression were tested, and the different buckling modes and ultimate strengths were analyzed in detail by varying the thickness, the length, the spacing of screws, the end fastener group, and the cross-sectional dimensions of CFS built-up I-sectional columns. It was shown in the test that noticeable interaction of local and distortional buckling or interaction of local, distortional, and global buckling was observed for the built-up I-sectional columns with different lengths and cross-sectional dimensions. A finite element model (FEM) was developed and validated with experimental results. A further parametric study has been conducted including different cross sections and slenderness ratios for the built-up I-sectional columns. The load-carrying capacities obtained from the experimental and numerical study were used to investigate the feasibility of the current direct strength method (DSM) when DSM was applied to CFS built-up I-sectional columns. The comparison results showed that the current DSM is not safe for CFS built-up columns failed in distortional buckling and interactive buckling. Therefore, the improved design formulas were proposed, and their accuracy was verified by using finite element analysis (FEA) and experimental results of CFS built-up I-sectional columns subjected to axial compression.

A New Design Method for Axially Loaded Thin-Walled Cylindrical Shells Based on Elasto-Plastic Buckling Analysis

2019 ◽  
Author(s):  
Peng Jiao ◽  
Zhiping Chen ◽  
He Ma
Keyword(s):  
Design Method ◽  
Cylindrical Shells ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Geometric Imperfections ◽  
Compression Load ◽  
Load Carrying ◽  
Weight Design ◽  
Thin Walled ◽  
Improved Design

Abstract In engineering, thin-walled cylindrical shells subjected to axial compression load are very sensitive to geometric imperfections and are prone to buckling. However, how to reasonably take into account the influence of geometric imperfections on the load carrying capacity of thin-walled cylindrical shells is always the bottleneck of light-weight design of these structures. In this paper, four perturbation load approach (4PLA) is adopted to consider the influence of geometric imperfections. By judging the potential buckling status of cylindrical shells, a new improved design method based on 4PLA for thin-walled cylindrical shells is proposed, in which the influence of radius-to-thickness ratio, length-to-radius ratio, Young’s modulus and material yield strength are systematically considered. Correspondingly, the buckling tests for two steel cylindrical shells with the same geometric and material parameters are conducted. Compared with the experimental results and other test results in open literatures, the superiority and safety of proposed method for the preliminary design of thin-walled cylindrical shells are validated.

Design of built-up steel beam-columns composed of two-channel sections

2020 ◽  
Author(s):  
George Iskander ◽  
Emam Soliman ◽  
Ezzeldin Yazeed Sayed-Ahmed
Keyword(s):  
Experimental Investigation ◽  
Numerical Model ◽  
Experimental Work ◽  
Parametric Study ◽  
Design Method ◽  
Steel Beam ◽  
Fe Model ◽  
Beam Columns ◽  
Initial Imperfections ◽  
Good Agreement

Built-up columns composed of two chords present an ideal design for long columns subject to high straining actions. The objective of this paper is to investigate the capacity of built-up columns composed of two-channel sections subjected to eccentric loading and propose a design method for them. A nonlinear numerical FE model is developed for these columns and verified against experimental investigation available from literature; the model includes both the geometric and materials nonlinearities along with the effect of initial imperfections. The model is used to perform a parametric study to investigate the effect of different factors on the built-up columns’ capacity. The results of the parametric study are also used to propose a design method for these columns. A limited experimental investigation is performed on two eccentrically loaded built-up columns, the results of experimental work showed good agreement with the numerical model results and the proposed design method.

A Method for Calculating Cracking Moment of FRP Reinforced Concrete Beam

2021 ◽  
Vol 896 ◽  
pp. 141-147
Author(s):  
Duy Nguyen Phan
Keyword(s):  
Reinforced Concrete ◽  
Modulus Of Elasticity ◽  
Parametric Study ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Reinforcement Ratio ◽  
Reinforced Concrete Beams ◽  
Comparison Results ◽  
Study Results ◽  
Frp Reinforcement

This paper presents an analytical method for calculating the cracking moment of concrete beams reinforced with fiber reinforced polymer (FRP) bars, which considers the non-linear behavior of concrete in the tension zone and the contribution of FRP reinforcement. Theoretical cracking moments obtained by the proposed method were verified with the experimental results and the theoretical results calculated according to ACI 440.1R-15. The comparison results show good agreement between theoretical and experimental data. A parametric study on the effect of longitudinal FRP reinforcement ratio and elastic modulus of FRP on the cracking moment of FRP reinforced concrete beams also were done by using the proposed method. The parametric study results show that both longitudinal reinforcement and modulus of elasticity of FRP significantly affect the cracking moment of FRP reinforced concrete beams. Moreover, parametric study results also clarify the weakness of ACI 440.1R-15 in determining the cracking moment of concrete beams reinforced with a large amount of FRP reinforcement ratio and with high modulus of elasticity of FRP.

Development of Simple Design-Oriented Procedure for Predicting the Collision Damage of FPSO Caisson Protection Structures

2010 ◽  
Author(s):  
Sang-Rai Cho ◽  
Jang-Hyun Jeong ◽  
Paul A. Frieze
Keyword(s):  
Structural Design ◽  
Parametric Study ◽  
Design Stage ◽  
Test Results ◽  
Simple Analytical Expression ◽  
Study Results ◽  
Commercial Package ◽  
Non Linear ◽  
Modification Factor ◽  
Protection Structures

Protection structures for FPSO caissons are required to be strong enough not to contact caisson pipes even when the protection structure is damaged by impact by attendant vessels. In the present structural design process, non-linear commercial packages are employed for the collision analyses. However, non-linear collision analyses using commercial packages are still time-consuming and expensive to operate especially at the initial design stage. In this study, validation of the adopted commercial package was firstly performed using collision test results on unstiffened tubulars. Then, a rigorous parametric study was conducted on simple protection structures by changing the collision velocity and the scantling of the protection structure. A simple analytical expression was derived assuming that the kinetic energy of the striking vessel is dissipated by plastic elongation of tubulars and rotation of plastic hinges. Using the parametric study results, an equation for the modification factor was obtained by which the effects of local denting and dynamic behavior can be considered. The developed procedure was also substantiated using numerically predicted extent of damages of an actual protection structure.

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