Two other forces which are crucial in understanding how to construct sturdy bridges and buildings are bending and torque. Bending is a force which causes a material to deform around a central axis. Bending can also cause tension and compression, so all of these forces are related. Torque can be thought of as a twist to an object. It causes a material to rotate around an axis or pivot.
Watch the Bending and Torque video to gain a better understanding of these topics.