Method, layout and accurate referencing to AS$/$NZS $1170$ and AS $3600$ clauses and or text books will be assessed in addition to answers obtained. Assume any missing data.

Question:

An office building in Robe of plan dimensions $33$m $\backslash$times $25$m$,$ and height $25$ m $(5$ storeys @ $5$m each$),$ constructed of ordinary moment resisting concrete frame, needs to be designed for earthquake action. Soil profile of the site consists of a layer of soil of $15$ m with undrained shear strength value of $15$ kPa, then a $10$ m layer with an undrained shear strength of $30$ kPa and then a $15$ m layer of soil with undrained shear strength of $35$ kPa. Below there is strong rock. Calculate earthquake base shear force and base overturning moment for the building according to AS $1170\mathrm{.}4.$ Maximum $250$ people can congregate in one area in this building.

Assume thickness of the slab$=250$ mm$,$ concrete unit weight$=25$ kN$/$m$3$ and superimposed dead load$=2$ kPa. Consider trafficking roof. Live load for office building should be considered according to AS $/$NZS $1170\mathrm{.}1$