Trykklast

Trykklast is a term used in civil and mechanical engineering to describe a load that acts on a surface due to a pressure field. It is defined as force per unit area exerted by a fluid—gas or liquid—on a boundary. The concept is used to model external loads on walls, façades, and shells, as well as internal pressures in vessels and piping systems.

Pressure sources are diverse: hydrostatic pressure from fluids at rest increases with depth according to p = ρ g h, with ρ the fluid density, g gravity, and h the depth. Dynamic or aerodynamic pressure arises from moving fluids and is commonly expressed as p ≈ ½ ρ v^2 multiplied by a coefficient that accounts for surface orientation and shape. In practice, pressure on a surface can be uniform or vary with height or direction.

In engineering design, trykklast is specified as a pressure per unit area (for example in kilopascals) and used to compute total forces by multiplying by the affected area. The resulting forces can be distributed over a surface, vary spatially, or differ on opposing faces (positive versus negative pressure). Time-varying or gusty loads may require dynamic analysis.

Standards and practice: many codes provide methods to estimate pressure loads for buildings and other structures, and to combine them with other actions under specified safety factors. Examples of contexts where trykklast is considered include wind loads on façades, hydrostatic pressure against water-retaining structures, and internal pressurization of vessels.