Precast/Prestressed Girder Help

Camber and Deflections

Camber and deflections are computed at all tenth points. Prestress uplift is computed by the moment-area method. Each strand group is treated separately with consideration given to individual strand transfer distances in the construction of the total M/EI diagram. Therefore, the effects of draping and multiple shield lengths can be handled accurately.

Long-term camber and deflections are computed by the growth multiplier method given in Reference 10, the PCI Design Handbook.

Live load deflection for each beam is calculated by multiplying the live load deflection value from analysis with the ratio of the bridge moment of inertia to the composite beam moment of inertia, and also, the distribution factor. Long-term deflections are computed by multiplying the initial/release calculations by factors specified in the PCI Design Handbook, Table 4.8.2.