Neglecting Elastic Gains

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jonathan_picking
Neglecting Elastic Gains

My DOT does not allow me to take advantage of elastic gains. I noticed that the factor for Service III is 1.0, so it appears that this is "baked in" is there a way to neglect elastic gains?

Rick Brice
Neglecting Elastic Gains

You can go into the Project Criteria and change the percentage of elastic gains considered. By setting them to zero, elastic gains are ignored.

From the Loads menu, you can change the load factors to anything you like. Set the Service III live load factor to your agency requirement.

If you are using PGSuper at your agency level, consider building your own configuration that has all your standard girders and sets the defaults and criteria per your agency rules.

jonathan_picking
Neglecting Elastic Gains

Thanks Rick,

Does this kick it to use gross section analysis? Code requires 1.0 for Ser. III, when including elastic gains. (0.8 if excluded)

Rick Brice
Neglecting Elastic Gains

You can choose gross sections or transformed sections in the Project Criteria. Elastic gains are implicitly included with transformed sections. The settings to control how much elastic gain is included is only available for gross sections.

While the LRFD spec ties the Service III load factor to method of prestress loss estimates (simplified or refined) and elastic gains (include or excluded), PGSuper does not. Some owners have their own rules for the Service III live load factor. WSDOT uses 0.8 with gross sections, refined losses, and elastic gains - but that is because we also design for simple spans.

In other words, set the Service III live load factor, losses, section properties, etc. to whatever you want it to be, per AASHTO or otherwise.

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