Ultimate limit state
The different verifications required by specific design codes are assessed based on the direct results provided by the model. ULS verifications are carried out for concrete strength, reinforcement strength, and anchorage (bond shear stresses).
To ensure a structural element has an efficient design, it is highly recommended to run a preliminary analysis that takes into account the following steps:
- Choose a selection of the most critical load combinations.
- Calculate only Ultimate Limit State (ULS) load combinations.
- To expedite the calculation time and address any issues, consider using a coarse mesh by increasing the multiplier of the default mesh size in the Setup (Fig. 27). If the model performs well, revert the multiplier back to a factor of 1.
Such a model will calculate very quickly, allowing designers to review the detailing of the structural element efficiently and re-run the analysis until all verification requirements are fulfilled for the most critical load combinations. Once all the verification requirements of this preliminary analysis are fulfilled, it is suggested that the complete ultimate load combinations be included and the use of fine mesh size (the mesh size recommended by the program). Users can change mesh size by the multiplier, which can reach values from 0.5 to 5 (Fig. 27).
The basic results and verifications (stress, strain, and utilization (i.e., the calculated value/limit value from the code)), as well as the direction of principal stresses in the case of concrete elements) are displayed by means of different plots where compression is generally presented in red and tension in blue. Global minimum and maximum values for the entire structure can be highlighted as well as minimum and maximum values for every user-defined part. In a separate tab of the program, advanced results such as tensor values, deformations of the structure, and reinforcement ratios (effective and geometric) used for computing the tension stiffening of reinforcing bars can be shown. Furthermore, loads and reactions for selected combinations or load cases can be presented.