Homework No$.1$:

Given: A prestressed simply supported I$-$beam with cross section shown has a span

of $200$ ft $,$ and is subjected to self$-$weight of $1,240plf.$

Concrete:

$f_c=10,000$ at shipping and final

$f_{ci}=8,000$ at release of prestress

$f_c=0\mathrm{.}45f_c$ allowable compressive stress

$fc=0\mathrm{.}6f_{ci}$ allowable compressive stress

$f_t=12\sqrt[\phantom{2}]{f_c^{\text{'}}}$ allowable tensile stress

Prestressing Strands:

$f_{pu}=270,000-$ ultimate strength

$f_{pj}=202,500-$ at jacking

$f_{pe}=145,000-$ at final after losses

$A_{ps}=0\mathrm{.}217i{n}^2$ per strand

Section properties are:

girder depth