Shear connectors (ULS) (Composite beams: BS 5950)

Tekla Structural Designer
Modified: 3 Oct 2019
2024
Tekla Structural Designer

Shear connectors (ULS) (Composite beams: BS 5950)

Tekla Structural Designer checks shear connectors to clause 5.4.7. It calculates the stud reduction factor based on the number of studs in a group.

Tekla Structural Designer always uses 2 * e (and not br) in the calculation of k for perpendicular profiles, and always uses br for parallel cases.

For angled cases two values of k are calculated and summed in accordance with clause 5.4.7.4. In this instance Tekla Structural Designer uses 2 * e for the calculation of k1 and br for the calculation of k2.

Warning: Caution: The value of e (when used) can have a very significant effect on the value of k. This can have a dramatic effect on the number of studs required for a given beam size. Alternatively for a fixed layout of studs this can have a significant effect on the required beam size.

Optimize shear connection

Stud optimization is a useful facility since there is often some over conservatism in a design due to the discrete changes in the size of the section.

If you choose the option to optimize the shear studs, then Tekla Structural Designer will progressively reduce the number of studs either until the minimum number of studs to resist the applied moment is found, until the minimum allowable interaction ratio (for example 40% for beams with a span less than 10 m) is reached or until the minimum spacing requirements are reached. This results in partial shear connection.

The degree of shear connection is checked at the point of maximum bending moment or the position of a point load if at that position the maximum utilization ratio occurs.

Note: During the selection process, in auto design mode point load positions are taken to be “significant” (i.e. considered as positions at which the maximum utilization could occur) if they provide more than 10% of the total shear on the beam. For the final configuration and for check mode all point load positions are checked.

To determine if the degree of shear connection is acceptable Tekla Structural Designer applies the following rules:

  • If the degree of shear connection at the point of maximum moment is less than the minimum permissible shear connection, then this generates a FAIL status,
  • If the point of maximum utilization ratio occurs at a point that is not the maximum moment position and the degree of shear connection is less than the minimum permissible shear connection, then this generates a WARNING status,
  • If the degree of shear connection at any other point load is less than the minimum permissible shear connection, then this does not affect the status in any way.
Note: The percentage degree of shear connection is always calculated by the program as a proportion of the maximum concrete force and not simply Na/Np as in the code.
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