How does a structural engineer plan for gravitational loads?
This is too generic to answer, but an engineer needs to account for the dead and live loads. Dead load is the weight of the structure itself and generally non variable loads. Live load are loads that can change. In a simple example of a bridge, the dead load is the weight of the load carrying member, either steel or concrete strucutral members, the weight of the wearing surface (i.e. pavement), sidewalks, etc. Live load is the weight of the traffic or pedestrians. These loads are derived from experience and reference. The weights of the members are well known or can be easily calculated. The live loads are derived from standard semi-empirical references or are by various codes such as AASHTO, etc. The gravitational load is different from the other types of loads such as uplift, harmonic, lateral, seismic, etc.
