Relation between Diaphragm and P-Jack Force.

Document Information

Document Type: FAQ

Product(s): LEAP CONBOX/CIP RC/PT Girder

Version(s): All

Original Author: Bentley  Bridge Technical Support Group - VM

QUESTION:  User has a two span post-tensioned box girder bridge with an integral pier.  When he/she added a diaphragm at the pier, the required P-Jack force is increased quite a bit. Explain how Conbox analyzes the diaphragm that would cause this increase in jacking force?

P-jack is designed at the support location where the diaphragm is present.
P-jack is designed for stress. Section properties used for stress calculation will be different with and without diaphragm. Since stress calculation will change, P-jack will change.