STAAD.Pro Help

D. BS8110 Column Design Principles

The BS8110 Column Design Brief is for prismatic, rectangular solid or circular shaped members.  Members may be built up from multiple elements, but only the member end moments are considered, so only single height columns are recommended.

Design Principles

Columns are designed for axial force and biaxial end moments, as well as biaxial shear.  Torsional moments are also included if specified in the design brief.  Reinforcement is provided by the program based on the forces generated in the Analysis mode and the code clauses outlined below.

The main reinforcing bars may be modified to allow for other bars passing through the section and then re-checked to ensure that the design requirements are satisfied.

All selected load combinations are used to calculate the required reinforcement.  The combination which produces the maximum required reinforcement area is called the 'Guiding Load Case', and the bar arrangement is chosen based on that combination.  Detailed printout of the design calculations is also for that combination.

The main reinforcing bars may be modified to allow for other bars passing through the section and then re-checked to ensure that the design requirements are satisfied.

Code Clauses Implemented

The following lists the code clauses used from BS 8110 Part 1:1997.

3.8 Column

  • 3.8.1 General.  Program Conforms
  • 3.8.1.1 Symbols.  Program Conforms
  • 3.8.1.2 Size of columns.  N/A
  • 3.8.1.3 Short and slender columns.  Program Conforms
  • 3.8.1.4 Plain concrete columns.  N/A
  • 3.8.1.5 Braced and unbraced columns.  Program Conforms

3.8.1.6 Effective height of a column

  • 3.8.1.6.1 General.  Program Conforms with Beta as a user input
  • 3.8.1.6.2 End conditions.  Program Conforms with Beta as a user input
  • 3.8.1.7 Slenderness limits for columns.  Program conforms
  • 3.8.1.8 Slenderness of unbraced columns.  Program conforms

3.8.2 Moments and forces in columns

  • 3.8.2.1 Columns in monolithic frames designed to resist lateral forces.  User decision
  • 3.8.2.2 Additional forces induced by deflection at ULS.  Program Conforms for column being designed, not for members connected
  • 3.8.2.3 Columns in column and beam construction or in monolithic braced structural frames.  Forces to be designed for are determined by the user's own model.
  • 3.8.2.4 Minimum eccentricity.  Program conforms

3.8.3 Deflection induced moments in solid slender columns

  • 3.8.3.1 Design
  • 3.8.3.2 Design moments in braced columns bent about a single axis.  Program Conforms
  • 3.8.3.3 Slender columns bend about a single axis( major or minor).  Program Conforms
  • 3.8.3.4 Columns where le/h exceeds 29, bent about their major axis.  Program Conforms
  • 3.8.3.5 Columns bent about their major axis.  Program Conforms
  • 3.8.3.6 Slender columns bent about both both axes.  Program Conforms
  • 3.8.3.7 Unbraced structures.  Program Conforms
  • 3.8.3.8 Deflection of unbraced column.  N/A
  • 3.8.3.9 Additional moments on members attached to a slender column.  N/A

3.8.4 Design of column section for ULS

  • 3.8.4.1 Analysis of sections.  Program Conforms
  • 3.8.4.2 Design charts for symmetrically-reinforced columns.  N/A
  • 3.8.4.3 Nominal eccentricity of short columns resisting moments and axial loads.  N/A
  • 3.8.4.4 Short braced columns supporting an approximately symmetrical arrangement of beams.  N/A
  • 3.8.4.5 Biaxial bending.  Program Conforms
  • 3.8.4.6 Shear in columns.  Program Conforms
  • 3.8.5 Deflection of columns.  N/A
  • 3.8.6 Crack control in columns.  The clause states that "if crack check is required, then the member should be checked as a beam"

N/A is to be interpreted as either not application or not implemented.

Clauses that do not appear in the list are deemed not to be considered by the program.