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Apply user defined utilization ratios

Added August 6, 2019 by Admin admin

Software version: 
Tekla Structural Designer 2019

Apply user defined utilization ratios

Apply user defined utilization ratios

By default designs and checks are performed against a utilization ratio (U/R) of 1.0.

To facilitate design optimization Tekla Structural Designer allows you to specify user defined U/Rs on an individual member basis (currently for Eurocode and US head codes only).

Note: Utilization ratio = actual performance value / maximum allowable performance value.

Overview of user defined U/R

When applied to the autodesign process user defined U/Rs introduce a measure of:

  • Conservatism - if the value is less than 1.0

  • Non conservatism - if the value is greater than 1.0

By not applying user defined U/Rs to the check process, you are still able to work to the original U/R of 1.0 when working in check mode.

User defined U/Rs can be applied to the following objects:

  • Members; steel and concrete columns and beams, composite beams, steel joists and braces. This includes separate settings for each span/stack/panel of continuous beams/columns/walls.

  • Steel Trusses - includes; Truss member top/bottom, Truss member side/internal.

  • Portal frames (Individual members within Frames are treated as steel columns and steel beams as appropriate).

  • Concrete Walls and Slabs including panels, patches, and punching shear checks.

  • Foundations; Pad Bases (Spread Footings), Strip Bases, Pile Caps, Mat and Piled Mat Foundation slabs and Piles.

Apply user defined U/R for autodesign only

Applying a value of utilization ratio < 1.0 for autodesign only introduces a measure of conservatism into the autodesign process but doesn't fail the member until the ratio default value of 1.0 is exceeded.

  1. Select the required element or elements.

    The properties of the selected elements are displayed in the Properties window

  2. Expand Utilization ratio and select Apply (to autodesign) , but do not select Apply to check
  3. Enter the Ratio limit as required.
    Note: For continuous beams/columns/walls you can apply separate ratio limits for the individual spans/stacks/panels if required.
When an Autodesign is performed, the design will be incremented to achieve a utilization ratio less than the ratio limit. When a Check is performed, the check will pass provided the utilization ratio is less than 1.0.

Apply user defined U/R for autodesign and check

Applying a value of utilization ratio < 1.0 for autodesign and check introduces a measure of conservatism into the autodesign process and fails the member when the ratio value that was set is exceeded.

  1. Select the required element or elements.

    The properties of the selected elements are displayed in the Properties window

  2. Expand Utilization ratio and select both Apply (to autodesign) and Apply to check
  3. Enter the Ratio limit as required.
    Note: For continuous beams/columns/walls you can apply separate ratio limits for the individual spans/stacks/panels if required.
When an Autodesign is performed, the design will be incremented to achieve a utilization ratio less than the ratio limit. When a Check is performed, the check will pass provided the utilization ratio is less than the ratio limit.
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