Comprehensive Design Example for Prestressed Concrete (PSC) Girder Superstructure Bridge

3. Flow Charts

Design controlling girder
Determine compression and tension stress limits at transfer (Design Step 5.6.1.1)
Determine final compression and tension stress limits (Design Step 5.6.2.1)
Calculate initial service moment stress in the top and bottom of the prestressed girder (Design Step 5.6.1.2)
Calculate final service moment stress in the top and bottom of the prestressed girder (Design Step 5.6.2.2)
Are service stresses within stress limits?

NO Select a different girder size or change strand arrangement and go back to 4

YES go to 7

Design the longitudinal steel at top of girder (Design Step 5.6.3)
Calculate factored flexural resistance, Mr, at points of maximum moment (S5.7.3.1) (Design Step 5.6.4)
Check the nominal capacity versus the maximum applied factored moment

NG Select a different girder size or change strand arrangement and go back to 4

OK go to 10

Check the maximum and minimum reinforcement (S5.7.3.3.2) (Design Step 5.6.4.1 and 5.6.4.2)

NG Select a different girder size or change strand arrangement and go back to 4

OK go to 11

Check negative moment connection at intermediate pier (Design Step 5.6.5.1)
Check moment capacity versus the maximum applied factored moment at the critical location for negative moment. (Design Step 5.6.5.1)
Check service crack control in negative moment region (S5.5.2) (Design Step 5.6.5.1)
Check positive moment connection at intermediate pier (Design Step 5.6.5.2)
Check fatigue in prestressed steel (S5.5.3) (Notice that for conventional prestressed beams, fatigue does not need to be checked) (Design Step 5.6.6)
Calculate required camber in the beams to determine bearing seat elevations (Design Step 5.6.7.1)
Determine the haunch thickness (Design Step 5.6.7.2)
Calculate required camber in the beams to determine probable sag in bridge (Design Step 5.6.7.3)
Optional live load deflection check (S2.5.2.6.2) (Design Step 5.6.8)

END.