LLDF calclation

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mdmetzger21@gma...
LLDF calclation
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Binary Data SID 7 U60s shorter span.pgs162.1 KB

Can't get PGSuper to ignore Range of applicability, ROA, for Live Load Distribution Factor, LLDF calculations even when toggled to do so. Also, can't get it to issue warning when outside ROA. Occurring when modeling tub girders (type c).

Rick Brice
The ignore range of

The ignore range of applicability feature seems to be working correctly for your file. Please provide additional information.

mdmetzger21@gma...
example

In the file attached, the spacing of interior girders is outside the ROA. The limit is 18 ft, but the spacing entered is over 20 ft. I calculate the lever-rule value for the LLDF (moment) as 1.52 and the equation value as 1.13. Here is what is happening for each given option toggled when parameters given are outside ROA:

When set to halt analysis and issue warning: program does not halt but goes forward using lever rule value.

When set to ignore ROA requirements and use equations: program still using lever rule values.

When set to use lever rule: program correctly uses lever rule value.

Rick Brice
PGSuper is working correctly.

PGSuper is working correctly. See LRFD 4.6.2.2.1.

"For beam spacing exceeding the range of applicability as specified in the tables in Articles 4.6.2.2.2 and 4.6.2.2.3, the live load on each beam shall be the reaction of the loaded lanes based on the lever rule unless specified otherwise herein."

Also see LRFD Tables 4.6.2.2.2b-1 and 4.6.2.2.2d-1. For type c cross section. S > 18.0 ft, use lever rule.

For your example, the lever rule is the correct method to distribute the live load.

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