FERMO building

Startup package for prestressed bed girder in building construction


New features in FERMO building construction

With version 22, in addition to the adaptations to run under Windows 11, additional enhancements are available in FERMO, which make the use of the program application even more versatile and efficient:

  • Enhanced graphics for calculation and design results, such as for the required torsional stirrup reinforcement in the top and bottom chords.
  • New tabular output of stresses in original load cases and load combinations at user-defined sections. The cross-section is displayed as a graphic at this position and indicated with the essential geometry and cross-section values.
  • Improved result graphics due to higher accuracy in calculation and design.
  • Improved determination of deformations in cracked state II by adapting the Krüger/Mertzsch method. The effective secant modulus of elasticity according to Zilch/Zehetmaier is now used. In addition, the effects of shrinkage curvature are now applied to all reinforcement layers. Likewise, net cross-section values are now used in the uncracked state to record the shrinkage curvature.
    The smallest effective bending stiffness from the min/max action combinations is now used to determine the governing effective bending stiffness EIw.
    These changes generally result in larger deformations.
  • Further improvements have been made for the design of recesses, the more accurate consideration of stripping and the consideration of fatigue loads
  • The cross-section database has been expanded to include the type V-girder with bracket. This cross-section type is now available for modeling main beams with a bearing bracket and can also be used as a composite cross-section. However, the type must not change along the beam axis
  • During the optimization of a girder, the results are often considered at only one desired section. In order to facilitate the evaluation at this section, an output list (Calculation/Output > User-defined sections only) can now be created, which contains all tables with the results of the user-defined sections only.
  • Additional check algorithms have been included for creating the tensile force envelope line. This includes checking whether the reinforcement is relevant for absorbing tensile forces and whether it is located in the area of moment zero points, notches or predominant tensile stress. The tensile force envelope line is determined with higher tolerances and can thus also be used safely for reinforced concrete beams.



Concrete girder Basic Module

The reinforced concrete design is carried out uniaxial. In detail, the following tasks can be solved with FERMO:

  • homogenous rectangular, T-beam, slab and H-sections with variable web and flange thicknesses as well as upstand beam and V cross sections with or without bulge
  • typed symmetric and non-symmetric cross-sections in longitudinal direction
  • arbitrary, variable cross-section layout including cross-section offsets
  • single symmetric, in special cases also asymmetric cross-section shapes, are possible but are designed uniaxial
  • subsequently applied in-situ concrete slab – i.e. composite cross-sections
  • varying, statically determinate systems: factory support, transport support, assembly support, auxiliary support and final support
  • maximum of 8 analysis moments along the timeline from the factoring up to the end of the lifecycle
  • linear stress resultants and deformations with automatic consideration of the effective slab widths
  • alternative consideration of normal strength concretes (up to C50/60), high strength concretes (C55/67 up to C 100/115), ultra-high strength concrete (UHC140)
  • reinforcement (up to B550), high strength reinforcement (SAS670)
  • edge related single reinforcement or distributed reinforcement
  • multi-layer reinforcement for single reinforcement and single-layer reinforcement for distributed reinforcement
  • Fixed, inner and variable, outer reinforcement layers that can be set either automatically or user-defined
  • minimum requirements for the concrete cover and durability
  • fixed or elastic support with automatic calculation of the spring constants
  • reliable generation of the design combinations with the aid of load case attributes
  • automatic generation of load cases by copying or copying with a certain distance
  • single loads, line loads, trapezoidal loads and triangular loads, temperature loads and support settlement
  • loads can be arranged centric or eccentric
  • linear stress resultant calculation with automatic generation of all design combinations
  • optional consideration of the minimum restraint, direct / indirect support
incl. Bearing capacity calculation
  • complete bearing capacity analyses in the ULS for the permanent, accidental and earthquake situation
  • minimum and ductility reinforcement for building construction and earthquake
  • minimum and robustness reinforcement for bridge construction
  • minimum reinforcement due to construction regulations
  • bending bearing capacity due to normal force / moment interaction
  • combination of the bending reinforcement under consideration of the minimum reinforcement
  • shear bearing capacity due to V-T-VT interaction with linear stress resultants
  • flange connecting reinforcement
  • composite joint reinforcement
  • tabular fire protection for decisive combination of actions (quasi-permanent, frequent)
  • additional analysis sections
  • summary of the existing and required reinforcement
  • summary of the material consumption (bill of quantities)
incl. Module design – building construction
  • basics for the general building construction, respectively, structural engineering according to EN 1990 appendix A1 and corresponding national annexes for DE, AT, SK/CZ and UK
  • live loads according to EN 1991-1
  • complete reinforced concrete and prestressed concrete design according to DIN 1045-1, EN 1992 1 and corresponding national annexes for DE, AT, SK/CZ and UK
  • specification of the longitudinal reinforcement as single or distributed reinforcement
incl. Module stressing bed prestressing
  • single-level prestressing
  • database with all common prestressing methods in the stressing bed
  • quick and easy input of the tendons with / without stripping
  • concrete strain and prestressing steel strain trajectories
  • prestressed concrete design under consideration of creep, shrinkage and short-term relaxation due to heat treatment
  • transmission and anchorage lengths
  • anchorage analysis of the stressing bed prestressing
  • tensile force coverage graphic for reinforcing and prestressing steel
  • bursting reinforcement for pretensioned tendons
incl. Module design of details
  • circular / rectangular recesses and notches at the girder ends
  • design of geometric discontinuity areas for small and large opening (recesses) according to DAfStb Heft 399/599 and DAfStb Heft 459
  • post design for openings really close to each other <  0,8 * h
  • design of geometric discontinuity areas for offset supports (notches)
incl. Module serviceability design
  • complete serviceability analyses in the SLS
  • reinforcement of the crack width for slim and thick structural members
  • minimum reinforcement due to the run-off of the hydration heat in the in-situ concrete slab
  • decompression analysis, if prestressing exists
  • limitation of the concrete compressive stresses II
  • limitation of the reinforcing and prestressing steel stresses II
  • limitation of the crack width (direct and indirect method)
  • limitation of the main tensile stresses in bridge construction
incl. Module refurbishment – building construction
  • bearing capacity analysis for refurbishment with utilization levels for a specified longitudinal and shear reinforcement under consideration of possible corrosion damages
  • no design – only the utilization levels, respectively, residual safeties are being determined



The FERMO prestressing girder in building construction is a powerful design program for precast and composite concrete girders and has the following special features:

  • Consistent program concept with overview at a glance
  • Program interface can be adapted for specific tasks
  • For both simple and complex engineering tasks in building and industrial construction
  • Configurable output for a wide range of requirements from pre-design up to the final inspection phase incl. detail output at user defined sections
  • Component-oriented load transfer with reliable transfer and organisation scheme

The best of both worlds

The combination of the prefabricated girder programs RTfermo and FETT is carried out in 2 stages through the successor program FERMO: RTfermo will be discontinued at the end of 2018 and FETT at the end of 2019. RTfermo will remain in product maintenance until 2019 and FETT until 2020.

The modular concept for FERMO corresponds in the broadest sense to the one of FETT, in which the use of high-performance concrete and fire protection design was integrated into the reinforced concrete base module.


Cover Picture: Bremer AG, Paderborn

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