$(3)$ Calculate the maximum stress at the edge of concrete slab $($under edge

loading$)$ using the Ioannides equation $($or Westergarrd equation$)$ with an

equivalent circular area calculated in $(1).(5$ points$)$

$(4)$ With a temperature differential of $20F($day time$),$ calculate thermal stress

at the edge of the slab $($infinite slab$).$ In addition, calculate the combined

stress due to temperature and wheel loading at the bottom of the slab. $(10$

points$)$