Difference between "Girder Line Pier Reactions" and "Girder bearing Reactions"

6 posts / 0 new
Last post
liuxueji
Difference between "Girder Line Pier Reactions" and "Girder bearing Reactions"

Could you please kindly clarify the Difference between "Girder Line Pier Reactions" and "Girder bearing Reactions" on girder detailed report? I am using PGSuper V5.0.2.0. Thanks!

liuxueji
It seems the program is

It seems the program is confused in adding up the reactions from the corresponding back and forward girders at a certain pier to get "Girder Line Pier Reactions" when there is a different number of girders in the back and forward. It seems it only works when the girders lined up or for continuous girders from the previous post.

bricer
Reactions

Girder line reactions are the reactions that occur for the structural frame model for an entire girder line. This reaction is typically maximized by the HL-93 90% of twu design truck spaced at least 50 ft apart and lane load. Girder line reactions are per lane values so the number of girders on either side of the pier isn't a factor.

Girder bearing reactions are the maximized reactions on individual bearing pads at a pier. The maximum reaction would occur for a single HL93 design truck and lane with the 32 kip axle directly above the bearing. Bearing reactions are per lane values so the number of girders on either side of the pier isn't a factor.

The girder bearing reactions in the Bearing Design Parameters are distributed to a per girder reaction with the shear live load distribution factor.

Consider a 2 span bridge with the intermediate pier being an expansion pier. The Girder Line reaction would be maximized by the HL93, 90% of two trucks case. This would be the maximum reaction on the pier for substructure design. The bearing pads on either side of the CL pier would experience different maximum reactions as described above.

liuxueji
Thank you very much for the

Thank you very much for the clarification especially on how the LL reaction is calculated. Could you please explain more on the dead load. If there is unequal amount of girders on the back and forward, how, for example, in "Girder Line Pier Reactions", girder reaction (It should be under girder self weight only) is calculated?

bricer
The girder line pier reaction

The girder line pier reaction is computed based on a girder line model. The dead load reaction would be for the dead load attributed to a girder line.

Slab loads are applied to the girders based on tributary width.

Barrier loads are based on the rules in the project criteria (typically divided amongst 3 exterior girder).

See Structural Analysis Models in the Technical Guide for more information about how the girder line analysis models are generated.
https://www.wsdot.wa.gov/eesc/bridge/software/Documentation/PGSuper/5.0/...

PGSuper does a girder line analysis. It does not do a full width bridge analysis so there isn't a total pier reaction. The reactions are limited to those generated by the simplified girder line models.

liuxueji
Thank you. Just want to

Thank you. Just want to confirm, for the "Girder Bearing Reactions", the load, e.g., the slab load, is calculated based on the simple-span with the corresponding distributive width, and the sum of all the girder bearing reactions from slab load should be equal to the superstructure slab load. The sum of those for "Girder Line Pier Reactions" is not because of the girder line models if there is unequal number of girders. Thanks.

Log in or register to post comments