Three$-$story shear frames with structural steel $(E=29,000$ksi$)$;$w=100$kips,$I=$

$1500i{n}^4,$ and ${}_n=5\%.$

Assuming the displacements to increase linearly with height above the base,

i$.$e Determine the story shears due to ground motion

characterized by the design spectrum of Fig. $6\mathrm{.}9\mathrm{.}5$ scaled to a peak ground

acceleration of $0\mathrm{.}25g.$