Problem $4($Comprehension $-$ How Variables Affect Strength & Ductility$)$

Analyze the effect of different variables on the strength and ductility of the beam from Problem

For parts $($a$)$ through $($e$)$ below, recalculate $M_n($strength$)$ and ${}_s($ductility$)$ if the stated change

is made in the beam.

$($a$)$ Concrete strength $)$ is increased $33\%$ to $33\mathrm{.}25$MPa.

$($b$)$ Steel strength $(f_y)$ is increased $33\%$ to $560$MPa.

$($c$)$ The amount of steel $(A_s)$ is increased $33\%$ to $265m{m}^2.$

$($d$)$ The beam width $($b$)$ is increased $33\%$ to $100mm.$

$($e$)$ The steel depth $($d$)$ is increased $33\%$ to $300mm.$

$($f$)$ Summarize the results in a table. Determine the $\%$ increase $($or decrease$)$ of $M_n$ and ${}_s$

from each variable. Answer the three questions listed below:

Which variables efficiently increase strength?

Which variables efficiently increase ductility?

What one variable increases both significantly?