Design of cold-formed beam-columns restrained by sheeting

Kari Kolari, Asko Talja

Research output: Book/ReportReport

Abstract

The load-bearing capacity and behaviour of laterally braced cold-formed sections has been studied in this project. The test program comprised 28 loading tests on cold-formed purlins continuously braced by trapezoidal sheeting and two tests where the purlins were connected to the gypsum board. The aim of the tests has been to determine the behaviour of single span purlin systems in combined compression and bending. The test program consists of centric and eccentric compression, bending with uplift and gravity load and combined compression and bending tests. A total of seven load cases for each of U-, C-, Z- and /sigma/-profiles were carried out. The test results are compared to design procedures determined by Eurocode 3 (1993), design of steel structures, draft annex A (part 1.3). The Eurocode 3 design method appears to give better results for C- and Z-profiles than for U- and /sigma/-profiles. It is also shown that the calculated ultimate loads according to Eurocode 3 are on average 62% conservative compared to tested results. The main reason for conservatism is in the effective length determination for the free flange. The fixed end boundary conditions used in VTT's tests are not included in the design expressions of Eurocode 3. The effective length for a beam on an elastic foundation with concentrated and distributed axial loading is derived using an energy method. The derived effective lengths are used with the Eurocode 3 design method. The use of correct effective lengths results in an average conservatism of 23 % in the design method. However, when the inelastic buckling of the free flange determines the ultimate load, the average conservatism is about 31%. The comparison is made between test and calculated characteristic resistance. Therefore the partial safety factor /gamma/M1 is set to 1.0. The accuracy of geometrically and materially non-linear finite element analysis of the /sigma/-profile is also verified. An example, where calculation of the C-profile according to Eurocode 3 is made, is included.
Original languageEnglish
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Number of pages92
ISBN (Print)951-38-4723-3
Publication statusPublished - 1994
MoE publication typeNot Eligible

Publication series

SeriesVTT Tiedotteita - Meddelanden - Research Notes
Number1608
ISSN1235-0605

Fingerprint

Flanges
Safety factor
Gypsum
Bending tests
Steel structures
Bearing capacity
Buckling
Loads (forces)
Gravitation
Boundary conditions
Finite element method

Keywords

  • beams (supports)
  • columns (supports)
  • structural members
  • structural steels
  • steel construction
  • cold working
  • steel sheets
  • load-carrying capacity
  • loads (forces)
  • tests
  • calculations
  • design
  • behaviour
  • steel structures
  • compression tests
  • bending
  • comparison
  • structural flanges
  • finite element analysis

Cite this

Kolari, K., & Talja, A. (1994). Design of cold-formed beam-columns restrained by sheeting. Espoo: VTT Technical Research Centre of Finland. VTT Tiedotteita - Meddelanden - Research Notes, No. 1608
Kolari, Kari ; Talja, Asko. / Design of cold-formed beam-columns restrained by sheeting. Espoo : VTT Technical Research Centre of Finland, 1994. 92 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 1608).
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Kolari, K & Talja, A 1994, Design of cold-formed beam-columns restrained by sheeting. VTT Tiedotteita - Meddelanden - Research Notes, no. 1608, VTT Technical Research Centre of Finland, Espoo.

Design of cold-formed beam-columns restrained by sheeting. / Kolari, Kari; Talja, Asko.

Espoo : VTT Technical Research Centre of Finland, 1994. 92 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 1608).

Research output: Book/ReportReport

TY - BOOK

T1 - Design of cold-formed beam-columns restrained by sheeting

AU - Kolari, Kari

AU - Talja, Asko

PY - 1994

Y1 - 1994

N2 - The load-bearing capacity and behaviour of laterally braced cold-formed sections has been studied in this project. The test program comprised 28 loading tests on cold-formed purlins continuously braced by trapezoidal sheeting and two tests where the purlins were connected to the gypsum board. The aim of the tests has been to determine the behaviour of single span purlin systems in combined compression and bending. The test program consists of centric and eccentric compression, bending with uplift and gravity load and combined compression and bending tests. A total of seven load cases for each of U-, C-, Z- and /sigma/-profiles were carried out. The test results are compared to design procedures determined by Eurocode 3 (1993), design of steel structures, draft annex A (part 1.3). The Eurocode 3 design method appears to give better results for C- and Z-profiles than for U- and /sigma/-profiles. It is also shown that the calculated ultimate loads according to Eurocode 3 are on average 62% conservative compared to tested results. The main reason for conservatism is in the effective length determination for the free flange. The fixed end boundary conditions used in VTT's tests are not included in the design expressions of Eurocode 3. The effective length for a beam on an elastic foundation with concentrated and distributed axial loading is derived using an energy method. The derived effective lengths are used with the Eurocode 3 design method. The use of correct effective lengths results in an average conservatism of 23 % in the design method. However, when the inelastic buckling of the free flange determines the ultimate load, the average conservatism is about 31%. The comparison is made between test and calculated characteristic resistance. Therefore the partial safety factor /gamma/M1 is set to 1.0. The accuracy of geometrically and materially non-linear finite element analysis of the /sigma/-profile is also verified. An example, where calculation of the C-profile according to Eurocode 3 is made, is included.

AB - The load-bearing capacity and behaviour of laterally braced cold-formed sections has been studied in this project. The test program comprised 28 loading tests on cold-formed purlins continuously braced by trapezoidal sheeting and two tests where the purlins were connected to the gypsum board. The aim of the tests has been to determine the behaviour of single span purlin systems in combined compression and bending. The test program consists of centric and eccentric compression, bending with uplift and gravity load and combined compression and bending tests. A total of seven load cases for each of U-, C-, Z- and /sigma/-profiles were carried out. The test results are compared to design procedures determined by Eurocode 3 (1993), design of steel structures, draft annex A (part 1.3). The Eurocode 3 design method appears to give better results for C- and Z-profiles than for U- and /sigma/-profiles. It is also shown that the calculated ultimate loads according to Eurocode 3 are on average 62% conservative compared to tested results. The main reason for conservatism is in the effective length determination for the free flange. The fixed end boundary conditions used in VTT's tests are not included in the design expressions of Eurocode 3. The effective length for a beam on an elastic foundation with concentrated and distributed axial loading is derived using an energy method. The derived effective lengths are used with the Eurocode 3 design method. The use of correct effective lengths results in an average conservatism of 23 % in the design method. However, when the inelastic buckling of the free flange determines the ultimate load, the average conservatism is about 31%. The comparison is made between test and calculated characteristic resistance. Therefore the partial safety factor /gamma/M1 is set to 1.0. The accuracy of geometrically and materially non-linear finite element analysis of the /sigma/-profile is also verified. An example, where calculation of the C-profile according to Eurocode 3 is made, is included.

KW - beams (supports)

KW - columns (supports)

KW - structural members

KW - structural steels

KW - steel construction

KW - cold working

KW - steel sheets

KW - load-carrying capacity

KW - loads (forces)

KW - tests

KW - calculations

KW - design

KW - behaviour

KW - steel structures

KW - compression tests

KW - bending

KW - comparison

KW - structural flanges

KW - finite element analysis

M3 - Report

SN - 951-38-4723-3

T3 - VTT Tiedotteita - Meddelanden - Research Notes

BT - Design of cold-formed beam-columns restrained by sheeting

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Kolari K, Talja A. Design of cold-formed beam-columns restrained by sheeting. Espoo: VTT Technical Research Centre of Finland, 1994. 92 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 1608).