Please wait a minute...

Frontiers of Structural and Civil Engineering

Front. Struct. Civ. Eng.    2019, Vol. 13 Issue (4) : 937-949     https://doi.org/10.1007/s11709-019-0528-4
RESEARCH ARTICLE
Structural behavior of intermediate length cold-formed steel rack columns with C-stitches
M. ANBARASU1(), Mahmud ASHRAF2
1. Department of Civil Engineering, Government College of Engineering, Salem 636011, India
2. School of Engineering, Deakin University Geelong, VIC 3216, Australia
Download: PDF(2769 KB)   HTML
Export: BibTeX | EndNote | Reference Manager | ProCite | RefWorks
Abstract

This article presents an experimental and numerical investigation on the strength and performance of intermediate length rack column sections with C-stitches under axial compression. The test program consisted of 10 axial concentric compression tests on columns with and without C-stitches under pin end conditions for two different geometric lengths. Finite element (FE) models were developed using commercial FE package ABAQUS considering material and geometric nonlinearities as well as initial geometric imperfections. The elastic buckling properties of the section were calculated using readily available linear elastic buckling analysis tools based on Generalized Beam Theory (GBT) and Finite Strip Method (FSM). Obtained FE results were compared with those obtained experimentally, and once verified the developed FE modeling technique was used to carry out a parametric study to examine changes in structural response due to variations in length, depth and spacing of C-stitches. Observed influences of C-stitches on the behavior and resistance of the considered columns were carefully analyzed, and key design aspects are presented herein.

Keywords cold-formed steel columns      C-stitches      intermediate length columns      distortional buckling     
Corresponding Authors: M. ANBARASU   
Just Accepted Date: 01 April 2019   Online First Date: 09 May 2019    Issue Date: 10 July 2019
 Cite this article:   
M. ANBARASU,Mahmud ASHRAF. Structural behavior of intermediate length cold-formed steel rack columns with C-stitches[J]. Front. Struct. Civ. Eng., 2019, 13(4): 937-949.
 URL:  
http://journal.hep.com.cn/fsce/EN/10.1007/s11709-019-0528-4
http://journal.hep.com.cn/fsce/EN/Y2019/V13/I4/937
Service
E-mail this article
E-mail Alert
RSS
Articles by authors
M. ANBARASU
Mahmud ASHRAF
Fig.1  Critical buckling curve Pcr-L
Fig.2  Cross section of rack column section (all dimensions are in mm)
Fig.3  Connection of C-stitches with rack column section
specimen
designation
web (mm) flange (mm) depth of lip (bl) t L d/L
bw w1 w2 bf w3 w4 w5
1250-C0-D0 180.1 21.2 75.1 150 60.1 42.4 58.3 15.1 1.56 1251 1/6135
1250-C1-D50 180.1 21.3 75.0 149 60.2 42.3 58.2 15.0 1.56 1252 1/5833
1250-C2-D50 180.1 21.4 75.1 149 60.0 42.3 58.4 14.9 1.56 1251 1/5743
1250-C3-D50 179.9 21.1 75.2 148 60.0 42.3 58.3 14.8 1.56 1252 1/4484
1250-C4-D50 179.8 21.1 75.2 151 60.1 42.4 58.3 14.9 1.56 1253 1/4634
1250-C5-D50 180.1 21.2 74.9 151 60.0 42.4 58.4 14.8 1.56 1253 1/4530
1800-C0-D0 180.1 21.3 74.9 152 60.1 42.2 58.5 15.1 1.56 1801 1/3435
1800-C1-D50 180.2 21.2 74.8 151 60.2 42.3 58.3 15.2 1.56 1799 1/3236
1800-C2-D50 180.1 21.3 74.9 149 60.0 42.3 58.4 15.1 1.56 1801 1/4358
1800-C3-D50 180.1 21.2 74.9 151 60.0 42.4 58.3 15.1 1.56 1802 1/3535
Tab.1  Average measured dimensions of the test specimens
Fig.4  Coupon test results. (a) Average stress-strain curve of the cold-formed steel; (b) initial part of the curve
Sl. No. thickness (mm) yield stress
fy(MPa)
ultimate stress fu (MPa) modulus of
elasticity E (MPa)
percentage of elongation
1 1.56 262.13 418.74 2.01 × 105 28.7
Tab.2  Material Properties of the Steel
Fig.5  Test setup for intermediate length rack columns
Fig.6  Load vs axial shortening curves. (a) For 1250 series; (b) for 1800 series; (c) for 1250-C0-D0; (d) for 1800-C0-D0
test No. specimen designation PTEST (kN) failure mode PFEA (kN) PTEST / PFEA
1 1250-C0-D0 110.2 D 108.6 1.01
2 1250-C1-D50 143.6 D+ F 142.3 1.01
3 1250-C2-D50 144.2 L+ F 143.2 1.01
4 1250-C3-D50 148.2 L+ D 150.1 0.99
5 1250-C4-D50 152.4 L+ D 154.8 0.98
6 1250-C5-D50 154.3 L+ D 157.2 0.98
7 1800-C0-D0 88.1 D 92.2 0.96
8 1800-C1-D50 112.2 D 107.2 1.05
9 1800-C2-D50 126.4 D+ F 129.2 0.98
10 1800-C3-D50 130.6 D+ F 133.2 0.98
mean 0.99
Std. Dev 0.025
Tab.3  Comparison of FE and experimental results for intermediate length rack columns.
Fig.7  Deformed shapes of test specimens. (a) For 1250 series; (b) for 1800 series
Fig.8  FE model with MPC constraint
Fig.9  Comparison of failure modes. (a) For 1250-C1-D50; (b) for 1250-C1-D50; (c) for 1800-C2-D50
Fig.10  Comparison of load vs axial shortening for 1250-C4-D50
Fig.11  Variation in fu/fy due to changes in No. of C-stitches (a/L ratio). (a) For 1300 series; (b) for 1800 series; (c) for 2300 series; (d) for 2800 series
Fig.12  Variation in fu/fy due to depth of C stitches (d/S). (a) For 1300 series; (b) for 1800 series; (c) for 2300 series; (d) for 2800 series
Fig.13  Variation in fu/fy due to slenderness of C-stitches (λs/λ). (a) For 1300 series; (b) for 1800 series; (c) for 2300 series; (d) for 2800 series
series base model C-stitches depth of C-stiches, D (mm)
percentage increase in resistance with respect to the base model
Nos. 25 50 75 100
1300 C0-D0 1 20.53 30.28 31.59 32.98
97.85 kN 2 19.79 30.02 27.88 32.64
3 22.20 34.93 40.18 42.35
4 23.56 39.77 44.14 48.56
5 24.53 45.01 51.86 55.75
1800 C0-D0 1 15.80 24.27 25.97 30.12
82.08kN 2 14.52 23.54 24.39 28.63
3 17.57 25.73 28.29 31.09
4 18.66 29.63 32.31 39.50
5 20.49 34.62 39.13 46.32
2300 C0-D0 1 7.01 10.78 10.95 12.57
68.76kN 2 3.82 4.90 7.18 15.04
3 10.05 13.89 17.44 18.64
4 12.78 16.39 22.45 24.97
5 15.29 21.84 27.39 30.13
2800 C0-D0 1 9.82 11.30 12.21 16.51
75.43kN 2 20.31 26.90 12.97 36.25
3 10.70 12.70 30.85 24.76
4 16.01 17.67 16.76 29.14
5 19.77 21.40 22.33 37.84
Tab.4  Change in columns strength due to changes in C stiches
1 P B Dinis, D Camotim. Local/distortional/global mode interaction in simply supported cold-formed steel lipped channel columns. International Journal of Structural Stability and Dynamics, 2011, 11(5): 877–902
2 W Zhou, L Jiang. Distortional buckling of cold-formed lipped channel columns subjected to axial compression. Steel and Composite Structures, 2017, 23(3): 331–338
3 T Zirakian, J Zhang. Elastic distortional buckling of singly symmetric i-shaped flexural members with slender webs. International Journal of Structural Stability and Dynamics, 2012, 12(2): 359–376
4 B W Schafer. Local, distortional, and Euler buckling in thin walled columns. Journal of Structural Engineering, 2002, 128(3): 289–299
5 K A Biggs, C Ramseyer, R Suhyun, T H K Kang. Experimental testing of cold-formed built-up members in pure compression. Steel and Composite Structures, 2015, 18(6): 1331–1351
6 G J Hancock. Distortional buckling of steel storage rack column. Journal of Structural Engineering, 1985, 111(12): 2770–2783
7 S C W Lau, G J Hancock. Distortional buckling formulas for channel column. Journal of Structural Engineering, 1987, 113(5): 1063–1078
8 S C W Lau, G J Hancock. Inelastic buckling of channel columns in the distortional mode. Thin-walled Structures, 1990, 10(3): 59–84
9 Y B Kwon, G J Hancock. Tests of cold formed channel with local and distortional buckling. Journal of Structural Engineering, 1992, 117(7): 1786–1803
10 J M Davises, C Jiang. Design for Distortional buckling. Journal of Constructional Steel Research, 1998, 46: 174–175
11 S Narayanan, M Mahendran. Ultimate capacity of innovative cold-formed steel columns. Journal of Constructional Steel Research, 2003, 59(4): 489–508
12 R S Talikoti, K M Bajoria. New approach to improving distortional strength of intermediate length thin-walled open section columns. Electronic Journal of Structural Engineering, 2005, 5: 69–79
13 M Veljkovic, B Johansson. Thin-walled steel columns with partially closed cross-section: Tests and computer simulations. Journal of Constructional Steel Research, 2008, 64: 816–821
14 M Anbarasu, S Sukumar. Study on the effect of ties in the intermediate length cold formed steel (CFS) columns. Structural Engineering and Mechanics, 2013, 46(3): 323–335
15 M Anbarasu, D Amali, S Sukumar. New approach to improve the distortional strength of intermediate length web stiffened thin walled open columns. KSCE Journal of Civil Engineering, 2013, 17(7): 1720–1727
16 M Anbarasu, S Sukumar. Finite element based investigation of performance of intermediate length columns with lateral stiffeners. Arabian Journal for Science and Engineering, 2014, 39(10): 6907–6917
17 M Anbarasu, S Sukumar. Influence of spacers on ultimate strength of intermediate length thin walled columns. Steel and Composite Structures, 2014, 16(4): 437–454
18 Simulia Inc. ABAQUS: Version 6.7–5, 2008
19 Council of Standards Australia. AS/NZS 4600:2005, Standards Australia, Sydney, Australia and Standards New Zealand, Wellington, New Zealand, 2005
20 S Gunalan, M Mahendran. Improved design rules for fixed ended cold-formed steel columns subject to flexural-torsional buckling. Thin-walled Structures, 2013, 73: 1–17
21 R Bebiano, N Silvestre, D Camotim. GBTUL 2.0 β –– Code for Buckling and Vibration Analysis of Thin-Walled Members. 2008
22 B W Schafer. CUFSM 3.12, Elastic Buckling Analysis of Thin-Walled Members by Finite Strip Analysis, 2006
23 Standards Australia. AS 1391–1991, Methods for Tensile Steel Structures, Testing of Metal. Sydney, 1991
24 M Anbarasu, G Murugapandian. Experimental study on distortional-global buckling mode interaction on thin-walled lipped channel. Materials and Structures, 2016, 49(4): 1433–1442
25 D Yang, G Hancock, K Rasmussen. Compression tests of cold-reduced high strength steel sections. II: Long columns. Journal of Structural Engineering, 2004, 130(11): 1782–1788
26 K Piyawat, C Ramseyer, T H K Kang. Development of an axial load capacity equation for doubly-symmetric built-up cold-formed sections. Journal of Structural Engineering, 2013, 139(12): 04013008
27 B Young, E Ellobody. Buckling analysis of cold-formed steel lipped angle columns. Journal of Structural Engineering, 2005, 131(10): 1570–1579
28 B W Schafer, T Pekoz. Computational modelling of cold-formed steel: characterizing geometric imperfections and residual stresses. Journal of Constructional Steel Research, 1998, 47: 193–210
29 S Jeyaragan, M Mahendran. Development and Validation of Finite Element Models of Back to Back Lite Steel Beams. Brisbane: Queensland University of Technology, 2009
Related articles from Frontiers Journals
[1] WANG Chungang, ZHANG Yaochun, ZHANG Zhuangnan. Experiments on channel columns with inclined simple edge stiffeners under compression loading[J]. Front. Struct. Civ. Eng., 2007, 1(3): 312-321.
Viewed
Full text


Abstract

Cited

  Shared   
  Discussed