Question $1(50$ marks$)$

The figure below show $3$D view of a one$-$storied reinforced concrete workshop building which to be constructed in Auckland CBD $(100$m away from coastline$).$ The beams supporting the one$-$way reinforced concrete slab with thickness of $200$ mm $.$ All columns are rigidly connected to the concrete footings.

Given:

Compressive Strength of Concrete is $35$ MPa $.$

Density of concrete is $\backslash (25\backslash$mathrm$\{$kN$\}/\backslash$mathrm$\{$m$\}^\{3\}\backslash ).$

Tensile strength of steel bar is $\backslash ($ f$\_\{$y$\}=300\backslash$mathrm$\{$MPa$\}\backslash ).$

Design working life is $50$ years.

$1.$ Determine the required steel bar area at point $\backslash ($ A $\backslash )$ and $\backslash ($ B $\backslash )$ as per the simplified method of NZS$3101.$ Note: Shear strength check is not required. $(20$ marks$)$

$2.$ Determine the number of steps $($Riser and Going$)$ and the required steel bar area $($main and thermal reinforcement$)$ for staircase CD as per NZS$3101.$ Note: Shear strength check is not required. $(30$ marks$)$

Note: Assume appropriate, realistic values for other design data that are not provided