What is the term for the forces that a structure must withstand?

The correct term for the forces that a structure must withstand is "load." In engineering and structural analysis, loads refer to the various forces and moments that are applied to a structure during its lifetime. These can include dead loads (permanent/static loads such as the weight of the structure itself), live loads (temporary/dynamic loads such as occupants, furniture, and equipment), environmental loads (such as wind, snow, or seismic activity), and others.

Understanding loads is crucial for structural design because it determines the materials and systems needed to ensure that the structure can safely support these forces without failure. Engineers calculate and analyze these loads to determine how a structure will behave under different conditions, ensuring that it meets safety and performance standards.