Question $3$

$[30]$

You have been tasked to design a staircase as shown in diagram Q$.3$ leads from a dormitory to a cantilever balcony in a multi$-$storey house in Kempton Park. The staircase will be cast between beams cast monolithic with the stair. Each stair will have a nosing of $18mm$ and a going of $250mm.$ The staircase should have a cement and sand plaster soffit $21mm$ thick and a $16mm$ thick Gneiss tile finish. Assume Y$10$ bars will be used for the longitudinal reinforcement. Design the staircase for a $1,5$ hour fire resistance and for severe exposure conditions. The characteristic concrete strength is fcu $=30$MPa.

Waist, W: $=300mm$

Height, $H$:$,=2340mm$

Width of support, b$,$sup: $=290mm$

Use the rclevant SANS codes to calculate the maximum ultimate shear force and bending moment $(8$ marks$)$ design suitable flexural reinforcement $(5$ marks$),$ design suitable distribution$/$transvers reinforcement $(2$ marks$),$ check the shear reinforcement is requited $(3$ marks$)$ and check if the spaneffective depth ratio is adequate $(6$ marks$).$ Complete the detailing diagram of the reinforcement on a neat sketch $(6$ marks$).$ Diagram not to scale.

Diagram Q$.3$