Design / Concrete

Prestressed Girder Design

Simple-span pretensioned AASHTO I-girder with a composite concrete deck, designed to the AASHTO LRFD Bridge Design Specifications: strand pattern, prestress losses, stresses at transfer and in service, Strength I flexure and shear with a stirrup layout, camber and deflection, and the fewest strands that pass. Interior or exterior girder; results update as you type.

Girder & span

Section

Span length, LCentre to centre of bearings

Girder spacing, S

Position

Deck overhangExterior girder CL to deck edge

Barrier base widthSets de to the barrier face

Number of girders

Design lanesFor live load deflection

Live load deflection limit

Deck

Structural thickness, t_s

HaunchWeight only, not in the section

Deck concrete, f'c

ksi

Girder concrete

At transfer, f'ci

ksi

At service, f'c

ksi

Relative humidity, HAverage annual ambient

Prestressing strand

Strand diameterLow-relaxation, 7-wire

Grade, f_pu

Number of strands

End treatment

Harped strandsFrom the centre column

Harped c.g. at endsAbove the soffit

Hold-down pointFraction of span from each end

× L

Debonded strandsEven number, each end

Debonded lengthFrom each end

Shear reinforcement

Stirrup bar

LegsVertical stirrups

Stirrup yield, f_y

ksi

Bearing lengthAlong the girder

Girder end past bearingFrom the bearing centreline

End bars (longitudinal)

Number of barsBottom flange, each end

Bar size

Yield, f_y

ksi

LengthFrom the girder end

At the girder end

Superimposed loads (per girder)

Barriers etc., DCOn the composite section

k/ft

Wearing surface, DW

k/ft

Corrosion conditionsSets the Service III tension limit