Steel member/segment design to NZS 3404:1997:

  • covers standard UB, UC, RSC, CHS, SHS, and RHS sections as well as custom welded I-sections and spiral welded pipe
  • flexure, axial, shear and combined actions
  • ambient temperature and fire design
  • elastic through to fully ductile design


Steel beam design capabilities for a single steel member:

  • simple, fixed or spring end supports
  • trapezoidal and point loading; applied end moments
  • basic load combinations
  • member segmentation
  • member strength (flexure and shear) and serviceability check

Release notes

V4.2  Date 31/7/2023

  • Update fy values used for CWB-G300M
  • Improve behaviour when loading incomplete data file
  • Better error handling on CWB screen
  • Update minor axis element slenderness limits applicability under seismic designs (see new Section 7.9.4 in User Manual)
  • Correct torsional constant J for RHS-S355 section library
  • Improve handling of non-standard regional settings
  • Add extended notes on weld performance to User Manual
  • Fix use of Table 12.5 for RHS sections
  • Fix possible incorrect display of calculations when multiple instances of MemDes are running
  • Include MemDes+/V1.7 with:
    • Negative distributed and point loading
    • User-defined applied end moments
    • Major update to assessment of critical flange and associated segmentation algorithm
    • Sagging moments now treated as positive
    • Graphics updates, especially labelling; show critical flange on segmentation diagram
    • Better error handling on CWB screen
    • Improve treatment on PCs with non-standard regional settings
    • Force creation of custom section folder on startup (avoids errors on some PCs)
    • Fix inconsistent treatment of invalid data when drawing MemDes+ loading diagram

V4.1  Date 30/6/2022

  • Allow for reduction of the gross cross-section area due to penetrations and holes
  • Update applicability of the alpha-m limit in Cl
  • Custom headers defined for PDF output of calculations
  • New standard section types WB/WC-G300+ and WB/WC-G400; update SHS/RHS availability
  • Fix interpretation of Table 5.2 for RHSs
  • New UI for Clear, Save, SaveAs, Open, MRU functionality + various other UI improvements
  • Fix calculation where web is critical under minor axis bending for asymmetric CWB
  • Alpha-m screen is now decoupled from design moment, and only defines the shape of the bending moment along segment
  • Include MemDes+/V1.6 with:
    • Field ‘sanity’ checks
    • Custom headers defined for PDF output of calculations
    • Inclusion of new standard section types
    • Adjust segmentation algorithm

V4.0  Date 5/11/2021

  • Customised properties for standard sections
  • User and project libraries of saved custom sections
  • User-specified fy for custom welded beams
  • Output calculations to PDF; improve calculation formatting
  • List most recently used files
  • Batch mode allowing multiple analyses in a single run
  • Update implementation of NZS 3404 Cl 8.1.4, Table 12.5 and Cl
  • Various UI improvements
  • Include MemDes+/V1.5 with:
    • Use of custom sections saved in MemDes section libraries
    • User-specified fy for custom welded beams
    • Report (unfactored) fixed-end moments for each load type
    • Batch mode

V3.8.2/1.4  Date 12/8/2021

  • Include MemDes+/V1.4 with:
    • Fixed deflection calculation for CWB
    • Use of decimal point in CWB input fields
    • Improved output formatting
    • Output calculations to PDF
    • Auto mode

V3.8.2  Date 4/6/2020

  • Fix implementation of NZS 3404 Cl for tapered beams
  • Batch/auto option
  • Add hollow sections to EN 10219

V3.8.1  Date 1/11/2019

  • Correct output detail when checking CHS section requirement
  • Fix incorrect slenderness check for CWB webs under minor axis bending
  • Include MemDes+/V1.2 with:
    • Inelastic design types and minimum section category
    • Custom welded beam option

V3.8  Date 30/04/2019

  • Retain saved and loaded moments used in assisted calculation of alpha-m
  • Include CWB-350 section type/grade
  • Correct implementation of Cl

V3.7.1  Date 26/11/2018

  • Update slenderness limits for RHS sections (refer NZS 3404 Table 5.2)

V3.7 Date 29/5/2018

  • Incorporate version 1.0 of MemDes+, which allows analysis and design of steel members (flexure, shear and deflection)
  • Improve report formatting
  • Fix application of Cl for CHS sections
  • Apply file type associations, and allow double-clicking in Windows Explorer to open data files
  • Fix minor UI issues

V3.6  Date 14/12/2017

  • Correct ordering of sections for some section types
  • Fix issue with properties of some square hollow sections not loading correctly

V3.5  Date 24/5/2017

  • First SESOC-branded version, with standard SESOC registration process.
  • Compatible with Windows 10, with an updated user manual and minor interface improvements. Includes some indication of section availability (especially hollow sections).
  • MemDes was originally written by New Zealand Steel Ltd as a design aid to professional structural engineers for the design of structural steel members to NZS 3404:1997.  In 2016, a version of MemDes was transferred to SESOC, and the software is now available from SESOC for the use of its members.

The following download includes both MemDes and MemDes+ bundled in a single install file:


MemDes v4.2 9.3 MB 1211 downloads

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