QUESTION $1[25$ MARKS$]$

A staircase shown in Figure $1$ spans longitudinally between masonry walls. The dead load of the finishes on the staircase is $1k\frac{N}{m^2},$ and the live load is $3k\frac{N}{m^2}.$

Given information:

Assume cover to reinforcement is $20$ mm and Y $12$ reinforcement bars for effective depth.

Characteristics strength of concrete$(f_{cu})$ is $25$ MPa

Use relevant Code of practice to do the following:

$1\mathrm{.}1$ Determine the design load$($s$)$ for the staircase

$(7$ marks$)$

$1\mathrm{.}2$ Calculate support reactions and maximum bending moment

$(5$ marks$)$

$1\mathrm{.}3$ Determine suitable longitudinal and transverse reinforcement bars. Do all necessary structural checks

$(13$ marks$)$

All dimensions in mm

Figure $1$: Staircase

PLEASE HELP ASAP