Area load

A surface load  f , sometimes also surface pressure , is a load caused by forces that are not concentrated (punctiform) or distributed over a distance , but that are continuously distributed over an area .

The term can be found in technical mechanics , especially statics .
In vehicle technology and road construction , the term 'surface pressure' was sometimes used until the middle of the 20th century, with the same physical meaning, but applied, for example, to the contact surface of a tire with the road.

A surface load results from a traction vector (e.g. surface pressure, tension, shear stress) (e.g. water level in a canal bridge or a volume force times the thickness).

A surface load is a stress that has the dimension force per surface , e.g. B .:

${\displaystyle f={\frac {\mathrm {d} F}{\mathrm {d} A}}}$

with the force . The ratio is formulated differentially , since the surface load is generally not constant over the surface . ${\displaystyle F}$ ${\displaystyle A}$

Special examples are the following effects in structural engineering :

• Payloads , for example the traffic load of a bridge , which is distributed over both the length and the width.
• Dead weight times the thickness of, for example, bridge girders and their traffic route superstructures ( coverings , bulk goods , rails )
• Wind loads on walls and roofs,
• Snow loads on roofs .

Typical area load assumptions can be found in the relevant standards or in construction tables (e.g. from Schneider construction tables , Werner Verlag).