고체역학 (Beer) — Pure Bending: Problem 4.117

4.117 Three steel plates, each of $25 \times 150\text{-mm}$ cross section, are welded together to form a short H-shaped column. Later, for architectural reasons, a $25\text{-mm}$ strip is removed from each side of one of the flanges. Knowing that the load remains centric with respect to the original cross section, and that the allowable stress is $100\text{ MPa}$, determine the largest force $P$ that (a) could be applied to the original column, (b) can be applied to the modified column.