Lastsituationen

Lastsituationen, in structural engineering, denote specific sets of loads acting on a structure at a given moment. Each Lastsituation defines the magnitude, direction, and distribution of forces that the element or building must withstand. They differ from a single Lastfall (load case) by representing a complete scenario used for analysis and design. In codes and standards, several standard Lastsituationen are defined and then combined into load combinations to assess safety and performance.

Typical examples of Lastsituationen include permanent (dead) loads from the structure itself, variable (live) loads from occupancy and use, environmental loads such as snow and wind, and, in seismically active regions, earthquake loads. Other considerations can include temperature effects, moisture, and service-time effects. For bridges, traffic loads may form a central part of the Lastsituationen; for buildings, occupancy and wind are frequently dominant. Designers also account for combinations of loads, such as dead loads with live loads, or dead loads with wind, or wind with snow, depending on the structure and code requirements.

The analysis workflow generally involves defining a standard set of Lastsituationen, applying load combinations per applicable standards (for example, Eurocode 0/1 in Europe), performing structural analysis to obtain internal forces and deformations, and verifying compliance with ultimate and serviceability criteria. The concept helps ensure reliability, safety, and functional performance under varying real-world conditions.