Problem $1$: Dead Loads

$($a$)$ What is the unit weight of reinforced concrete?

$($b$)$ What is the unit weight of structural steel?

$($c$)$ The floor system of an apartment building consists of a $4-$in$.-$thick reinforced concrete slab resting on three steel floor beams, which in turn are supported by two steel girders, as shown in Fig. $1.$ The areas of cross section of the floor beams and the girders are $18\mathrm{.}3$ in$.{?}^2$ and $32\mathrm{.}7$ in$.{?}^2,$ respectively. Assume that the beams are simply supported at the girders and that the girders are simply supported at the columns.

Figure $1$: The floor system of an apartment building

$($i$)$ Determine the dead loads acting on the beam CD and the girder AE$.$ Draw neat sketches to show how you determine the dead loads on beam CD and girder AE $.$

$($ii$)$ What are the support reactions at the ends of beam CD$?$

$($iii$)$ What are the support reactions at the ends of girder AE$?$

Problem $2$: Live Loads

$($a$)$ Why is the minimum live load lower for an apartment building than it is for a warehouse?

$($b$)$ What is the minimum live load for an apartment building?

$($c$)$ Why is live load expressed in pounds per square foot and not pounds per cubic foot as is the case with dead load?

$($d$)$ For the apartment building whose floor system was described in Problem $1/$Part $($c$)($See Fig. $11),$ solve the following problems:

$($i$)$ Determine the live loads acting on the beam CD and the girder AE$.$ Draw neat sketches to show how you determine the effect of floor live loads on beam CD and girder AE$.$

$($ii$)$ What are the support reactions at the ends of beam CD due to live load?

$($iii$)$ What are the support reactions at the ends of girder AE due to live load?