Question #$2.$

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 $=1\mathrm{.}0.$

strand pattern at midspan