Structural Analysis Wiki

The Dlubal Structural Analysis Wiki explains technical terms used in structural analysis and design. The terms are given in alphabetical order and are usually used in Dlubal Software.

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2025-02-18

HOAI

Joint Group

Keyboard Functions

Quadrangle Surface

ULS – Ultimate Limit State

ULS stands for "Ultimate Limit State" and describes the state in which the structural component under consideration is subjected to the most unfavorable load.

The ultimate limit state design is used to ensure the stability of structural components. Exceeding this limit state may lead to the failure of the structure.

The Eurocode distinguishes various design situations for the action combinations of the ultimate limit state:

Permanent and transient action E_d

E_{d} = \sum_{j \geq 1} γ_{G, j} \cdot E_{Gk, j} + γ_{Q, 1} \cdot E_{Qk, 1} + \sum_{i > 1} γ_{Q, i} \cdot ψ_{0, i} \cdot E_{Qk, i}

E_d	Design value of loading for permanent and transient actions
γ	Safety factor
ψ	Combination coefficient

Action Combination for Permanent and Transient Loading

Accidental action E_dA

E_{dA} = \sum_{j \geq 1} γ_{GA, j} \cdot E_{Gk, j} + E_{Ad} + γ_{QA, 1} \cdot ψ_{1, 1} \cdot E_{Qk, 1} + \sum_{i > 1} γ_{QA, i} \cdot ψ_{2, i} \cdot E_{Qk, i}

E_dA	Design loading value for accidental loading
γ	Safety factor
ψ	Combination coefficient

Combination of Actions for Accidental Loading

Loading due to earthquake E_d

E_{d} = \sum_{j \geq 1} G_{k, j} " + " P " + " A_{Ed} " + " \sum_{i \geq 1} ψ_{2, i} \cdot Q_{k, i}

G_k,j	Charakteristischer Wert einer ständigen Einwirkung j
P	Maßgebender repräsentativer Wert einer Vorspannung
A_Ed	Bemessungswert einer Einwirkung infolge Erdbeben
Q_k,i	Charakteristischer Wert einer nicht maßgebenden veränderlichen Einwirkung i (Begleiteinwirkung)
'+'	'ist zu kombinieren'
∑	'gemeinsame Auswirkung von'

Seismic Design Situation

In RFEM and RSTAB, it is possible to automatically generate load combinations based on a design situation for various loads according to the Eurocode.