A two$-$storey residential $($ordinary$)$ building is shown in Figure Q$3,$ where the value next to each

column indicates the corresponding lateral stiffness. The mass of each whole floor is $1000$ tonnes.

The building is situated in a region with a reference PGA of $16,5\%$g $($TNCR $=475$ years$)$ and where

seismic hazard is dominated by events with a surface wave magnitude less than MS $5\mathrm{.}5.$

The shear wave velocity of the site is estimated to be $500$m$/$s$.$

The sample structure is a shear$-$type building.

Using a linear mode shape, the first mode natural period is estimated to be $0\mathrm{.}50$s$.$

Assume a damping ratio of $5\%$ and a behaviour factor of $4\mathrm{.}0$