Final answer:
Moment resisting frames deal with lateral forces through the bending of beams and columns, with joints that withstand large moments and shears. They maintain stability by redistributing stresses and acting as a rigid body in equilibrium, using principles depicted in free-body diagrams.
Step-by-step explanation:
How does a moment resisting frame react to lateral forces? Moment resisting frames are structures designed to resist lateral forces through the bending of columns and beams. These frames provide support to a building by forming a skeleton that can handle the bending moments caused by wind or seismic activity. In the presence of lateral forces, components of these frames, particularly the joints at the ends of beams and columns, handle large moments and associated shears, keeping the structure intact. The frame acts similarly to a rigid body in equilibrium, with the normal reaction force and static friction at the base resisting motion, much like forces in contact with the floor that prevent a ladder from slipping. By selecting the base as the pivot location, the moment arms of these forces reduce to zero, thus preventing any torque due to the normal and friction forces at the pivot.
For a better understanding, consider free-body diagrams that show the applied forces, their points of application, and associated moment arms. The same principles apply to a moment resisting frame when determining how it reacts to lateral loads; forces and torques are analyzed to ensure the structure stays in equilibrium, with the ability to redistribute and manage the stresses caused by external forces. This ability to resist moments is crucial for maintaining the stability of buildings during dynamic loads such as earthquakes.