How to Design a Steel Angle Lintel to AS4100:1998

ClearCalcs produces an easy to use online calculator for the design of steel angle lintels. Watch the below video for a quick overview of how to use the calculator, and then log in to ClearCalcs or sign up for a free trial to test it out.

Scope

This sheet calculates maximum design actions and their associated capacities for a steel equal and unequal angle, purposed as a lintel that generally supports masonry.

angleLintelB1Down.svgangleLintelB2Down.svgangleLintelB1Up.svgangleLintelB2Up.svg

General Notes

  • The user inputs the length, effective length, and applied loads on the lintel
  • Wind loads are calculated by the user in accordance with the appropriate standards
  • The member section is checked against bending, shear, torsional stresses and deflection
  • The sheet is a computation for a single member in isolation

Assumptions and Limitations

  • The computation is meant for a member in isolation, therefore is not indicative of a member in a frame group
  • The lintel is assumed to support masonry loads, therefore the load configuration is assumed to be line loads only (no point loads or applied torques along the member)
  • While torsional effects are considered, the rotational effects of the loads are not considered, therefore rotation should be investigated according to engineering judgement. Excessive rotation could lead to wall destabilisation due to the shifting of the centre of gravity of supported masonry
  • As lintels support mostly dead loads, the limit state is defaulted to 1.35G, for long term strength ultimate limit state for dead loads only
  • All loads are assumed to apply along the same plane perpendicular to the horizontal leg of the angle lintel
  • All loads are assumed to share the same eccentricity
  • Eccentricity of loads are assumed to be between the edge of the upright (vertical) angle leg and the toe of the angle section. It is defaulted to the middle, and can be overridden by the user for analysis purposes
  • Second order deformation (P- effects) is not considered in the deflection analysis
  • Temperature effects are not considered
  • The lintel is assumed to only be either free from lateral restraint, or fully laterally restrained along the lintel. Complex restraint behaviour is not considered
  • All vertical loads are assumed to also contribute toward a proportional horizontal load, if it is restrained from deflecting laterally. Otherwise, the vertical line load will cause the angle section to also deflect laterally as the principal axes of the section does not coincide with the geometric axes.
  • Members include only Equal and Unequal angles from the OneSteel manufacturing tables.

References

AISC Design Guide 9
AS1170.0 Structural Design Actions: General Principles
AS4100-1998 Steel Structures
Gorenc, B.E. & Tinyou, R. & Syam, A. A. (2012) Steel Designer’s Handbook. Sydney, NSW:New South Publishing
OneSteel (2014) Hot Rolled and Structural Steel Products. OneSteel Manufacturing
Trahair, N. S. (2001) Lateral Buckling Strengths of Steel Angle Section Beams. Journal of Structural Engineering. 784-791
Trahair, N. S. (2001) Moment Capacities of Steel Angle Sections. Journal of Structural Engineering. 1387-1393
Trahair, N.S. (2001) Bearing, Shear and Torsion Capacities of Steel Angle Sections. Journal of Structural Engineering. 1394-1398
Trahair, N.S. (2001) Buckling and Torsion of Steel Unequal Angle Beams. Journal of Structural Engineering. 474-480
Trahair, N.S. (2001) Design of Steel Equal Angle Lintels. Journal of Structural Engineering. 539-545

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