Question $4..................................................................................10$ marks

Fig. $5$ shows a bowstring arch truss that you have used as the basis of bridge you are designing. We

know that all the top chords $(AI,IH,HG,GF)$ form an arc of radius $50$ m $.$ The applied loads are

$L=37\mathrm{.}5kN$ as shown.

Remember that all truss members are considered two$-$force members.

$($a$)$ Determine the support reactions at A and $F,$ respectively.

$($b$)$ Find the force carried in members $AB,BI$ and $CI$ and determine whether they are in tension or

compression.