Initial PC Girder Bearing Seat Grade Calculation

cmoreride · Jul 26, 2019

Just did 12 spans graphically and it appears to be a simpler and quick method.
BTW I checked all 12 spans results and were at or within 0.01'
Assumes Road Vertical Curve greater than Span Length

• Max Midspan Girder camber value “GC”
• Max Midspan Dead load deflection value “DL”
• Max Midspan Residual Road Profile “RP”
• Grade adjustment at CL Bearing “GA”

Road Profile Curve
GC-DL-RP=GA

Road Profile Sag Curve
GC-DL+RP=GA

Further adjustments of:
Minimum haunch and cross slope to CL Girder
Bearing thickness

BridgeSmith · Jul 26, 2019

Graphically is definitely a good way to check the mathematical approach to make sure you've added and subtracted correctly. It will also give you an easy way to calculate the volume of the leveling overlay, soffit, or slab. Draw the curve for the finished grade (final surface elevations). Draw the final shape of the girder after camber, deflection, etc. at the time of interest (the shape of the girder will change over time). Superimpose the 2 curves and adjust so that the girder is below the finished grade everywhere by the minimum thickness of the overlay, soffit or slab.

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Initial PC Girder Bearing Seat Grade Calculation

cmoreride

Civil/Environmental

BridgeSmith

Structural

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