When an earthquake occurs, several types of loads act on a reinforced concrete (RC) structure. These loads are primarily due to the ground motion and can be categorized as follows:1. Lateral Loads (Horizontal Loads):- Inertial Forces: During an earthquake, the ground shakes, causing the building to accelerate. The mass of the building creates inertial forces that act horizontally. These forces are proportional to the building's mass and the acceleration of the ground motion. These horizontal forces are a major cause of damage in structures during earthquakes.- Shear Forces: These are the forces that act along the horizontal planes, causing different parts of the structure to move in opposite directions. This action results in a shearing effect, which can cause significant damage to the structure, especially in the connections and the base.2. Vertical Loads:- Axial Loads: Although vertical acceleration components are usually less critical than horizontal components, they still impact the overall load distribution within a structure. Vertical ground accelerations can cause additional axial loads in columns and walls. These loads can either increase or decrease the axial forces depending on the direction of the acceleration and the structure's mass.When designing RC structures for earthquake resistance, engineers must consider all these loads and their combined effects to ensure the building's stability and integrity during seismic events.