Limit States

Herein users may define the Limit States or the Performance Levels to be used to check the structure.

In the cases of the Eurocodes, the state of damage in the structure is defined through three limit states, namely Near Collapse (NC), Significant Damage (SD) and Damage Limitation (DL). It is noted that the selection of the limit state(s) that need to be checked in a country may be found in the relevant National Annex. As a result selection of a National Annex from the available ones will define whether all Limit States, two or one of them will be employed during the Code-Based-Checks.

The performance levels employed in ASCE 41-23 consist of combinations of the target building performance levels (Operational Level, Immediate Occupancy, Life Safety and Collapse Prevention) and seismic actions (2%, 5%, 20% and 50% probabilities of exceedance of the seismic action within a conventional life cycle of 50 years).

The corresponding limit states for the Italian Code are four, i.e. limit state of Operational Level (OL), Damage Limitation (DL), Life Safety (LS) and Collapse Prevention (CP). Apart from the considered limit states, users may specify the location of the structure in the Italian territory, the life time of the structure and its importance class, and the parameters needed for the spectra derivation are automatically calculated.

The performance objectives employed in KANEPE consist of combinations of the performance requirements (Immediate Occupancy, Life Safety and Collapse Prevention) and seismic actions (10% and 50% probabilities of exceedance of the seismic action within a conventional life cycle of 50 years).

The performance levels for the TBDY consist of combinations of the target building performance levels (Continuous Use, Immediate Occupancy, Life Safety and Collapse Prevention) and seismic actions (2%, 10%, 50% and 68% probabilities of exceedance of the seismic action within a conventional life cycle of 50 years).