GEO5 version 10
Analyses according to Eurocodes

The work of all European structural and geotechnical engineers has been affected by the implementation of unified European Standards (EN). All areas of structural design, from the load and its combinations over analysis of structures and dimensioning to foundations and geotechnical analysis have been influenced by this change. The necessary changes had to be implemented in our software – some programs have been modified, others were created completely new.

We devoted the year 2009 exclusively to creation of the software according to European Standards and so we can introduce many innovations in geotechnical programs GEO5.

Classical analysis/ Analysis according to EN

The main innovations of GEO5 version 10 are the automatic analyses according to Eurocodes EN 1997-1 and EN 1998-5. The actual methods of analysis (earth pressure determination, bearing capacity of foundation soil, stability analysis) remain unchanged – Eurocode does not deal with the individual analytical methods in detail. Therefore there was no reason for changes. However the verification “philosophy” has been changed entirely and is now significantly more complicated e.g. there are dozens of possible combinations of partial factors for a simple gravity wall analyses.

Design approaches

Choice of the design approach is the first important step for analysis according to Eurocodes. One of the design approaches reccomended in National Annex should be chosen for a certain typ of the structure in every EU country. All design approaches calculate with partial factors on action (F – force). All the forces used in the analysis are multiplied by these partial factors.

• Design approach 1 further introduces reduction of soil parameters (M – material). This approach requires two computations for two combinations (either F or M is reduced) and selection of the most unfavourable option.
• Design approach 2 introduces reduction of resistance (R – resistance), which reduces the final resisting forces (bearing capacities, overturning moment...).
• Design approach 3 reduces soil parameters (M) and action (F) at the same time. It distinguishes between the structural action (STR) and the geotechnical action (GEO) having to different partial factors.

Input of partial factors

The software includes a table for the design approach choice and the input of the partial factors relevant to the particular program. The program includes standard partial factors according to Eurocode. However all the partial factors can be modified based on National Annexes or user’s needs.

There is going to be a possibility of option amongst individual National Annexes in the future. However they are not yet finished in many countries. Therefore the software currently includes only the standard partial factors according EN 1997-1.

Actual verification

The actual analysis is significantly more complicated compared to the classical way. Every force has got assigned different partial factors for different cases of failure depending on whether it acts favourably or unfavourably. For example own weight of the wall acts favourably for slip and overturning verification, whereas it acts unfavourably (increases the stress) on bearing capacity of the foundation soil, although it can act favourably as well (for greater eccentricities). It is therefore necessary to carry out a number of computations. There is the final combination of the partial factors for individual cases of failure displayed in the programs as a control for the user.

Design Situation

The software includes design situations according to EN 1990 – Persistent, transient, accidental and seismic. Design situation determines which set of partial factors will be used in analysis.

Stability analysis

Weight of the individual slices is multiplied by the partial factor in the slope stability analysis depending on whether it acts favourably or unfavourably. There is further soil parameters reduction in design approaches no.1 and no.3 or the total resistance on the slip surface in design approach no.2. The input surcharge is reduced by the partial factor as a whole.

Plate programs

Beam and Plate programs allow input of action states according to EN 1990. The programs further comprise an automatic generator of load combinations according to EN 1990 including vast options for user modifications of the action states (selection and the main actions definition, definition of the loads acting together or the loads not acting together), that speeds up and simplifies the work with creation of combinations. The generator allows generation of standard and alternative combinations, further combinations for ultimate limit state and service-ability limit state analysis.

Innovations in FEM, Tunnel programs

Version 10 includes new material models – hardening and softening for Mohr-Coulomb and Drucker-Prager, CAP model for Drucker-Prager and generalised Cam-Clay model. We are currently preparing steady flow with a link to the slope stability analysis for version 11.

Planned development

Analysis according to Eurocode have been fully completed in the following programs: Gravity Wall, Gabion Wall, Slope Stability, Spread Footing, Sheeting Design, Sheeting Check, Masonry Wall, Prefab Wall. We are planning implementation of Eurocodes into all relevant programs for version 11 (Piles, Nailed Slopes, Abutment, Plate) and further the application of the individual National Annexes, assuming they will have been finished by then.

Read the release history for more details about GEO5 version 10 or download demo version for free and try it for yourself.

• Geotechnical software GEO5
• Structural Analyses FIN10
• Roof Truss Design TRUSS4