Given the slab shown in figure, determine:

a$)$ its punching shear resistance, $v_{Rd,c}$

and, if required, calculate:

b$)$ the effective design strength of the punching shear reinforcement, $f_{ywd,ef}$

c$)$ the shear reinforcement ratio $(\frac{A_{sw}}{s_r}{u}_1)$ that should be provided at the basic control perimeter according to Eurocode $2$ to resist a punching shear load of $V_{Ed}=320kN$ at column $C1$

d$)$ The distance from the column at which punching shear reinforcement is no longer required, $r_{\text{o}\text{u}\text{t}}$

Data provided

$f_{ck}$:$30$Mpa

Slab depth: $400mm$

Concrete cover: $30mm$

column dimensions: $300300mm($square column$)$

Plan view

Typical cross section through slab$-$column C$1$ connection $($only slab floxural reinfoncement is shown$)$

Slab flexural reinforcement: H$16$@$150$ c$/$c $($all layers use the same bars at given spacing$)$