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$\%20$Bridge$\%20$Girder$\%20$Design$\%20$Example.pdf

CE $648$ Homework #$3.$pdf

Page $2$ of $3$

A simple$-$span bridge superstructure uses adjacent box beams. Its span is $95$ ft $.$ The precast prestressed concrete beam cross section, strand pattern at midspan, and moment due to various loads at an interior beam are provided below. The beams use $0\mathrm{.}5$ in$.$ diameter, Grade $270$ lowrelaxation strands. Concrete strength at $28$ days $=5,000.$ Determine the factored flexural resistance $M_n$ of the beam at midspan and check whether the factored flexural resistance is sufficient following the AASHTO LRFD Bridge Design Specifications. Assume $=1\mathrm{.}0.$

Beam section

Strand pattern at midspan