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selfsupportingframework mockup

by Mischa, Aug 19, 2010 22.00


Some call it Mandala Roof or reciprocal frame. That describes a load bearing principle known since centuries. Using it one can bridge a span wider than the length of each beam by connecting these elements at the end in an arrangement that allows the bending moment to run continuously through the framework.

One main research topic at the chair of Structural Design at the Faculty of Architecture at University Kassel is the development of parametric tools for different usages. Particularly in combination with the material timber this load bearing principle seemed to promise advantages. Guided by Prof. Manfred Grohmann and Dipl.-Ing. Asko Fromm the students Andreas Günther and me started with this principle and developed it further to allow to use it for theoretically any double curved spatial structure. The programs calculates the length of all beams and the detailed position and geometry of all cuts and connecting bolt-holes. Before all these data for production become necessary the geometry is exported into a calculating program which checks the structural behavior and an optimization can be done.

As part of my master thesis I transferred this workflow to a demonstration building using a very fruitful cooperation with the education center of the German Carpenter Association based in Kassel. The data generated by the program was used by a group of young carpenters to transfer in total about 2.5 m³ of timber with the dimension 100 by 100mm into the 180 beams of the framework using a numerically controlled cutting machine. After a kind of nesting the machine cuts all the beams to the appropriate length. Within the same step all the 324 cuttings are milled into the timber from both sides. This was arranged in a way the cross-sections only are weakened at the end of the beams. With the help of the same group of young carpenters the demonstration building was finally erected at University Kassel.

Used scripts

Why are these buttons gray?

  • 3. Hanno (Aug 26, 2010 17.37):

    Hi Mischa,

    great project, thanks for showing! I corrected the script links, this was indeed a problem in our engine.


  • 2. Mischa (Aug 23, 2010 14.31):

    First thanks a lot for rewarding the project!

    But there is a little mistake concerning the used scripts.
    I used
    - Array Library RhinoScript Library by Hanno
    - Rhinoscript connection to Open Office Calc and Rhinoscript connection to Open Office Calc (export points) RhinoScript Tools by fraguada
    - Perpendicular_line and divide_cos_sin_tan RhinoScript Tools by me

    -We use “R_stab” because the structure is a framework. But you can use any structural analysis program.
    -The connection detail is a simple cut-out connected by double-threaded fasteners.
    -We are able to use a Hundegger K2 during our cooperation. The control of Fully Automated Joinery Machine K2 is done by a special program. The geometry data is exported by a list of processings as numeric code.
    -Hardware? I wrote a Script to create the geometry, the data for structural analysis program and for the production file. All these calculations are done by a Laptop (Think Pad T 500).
    -The structure is grounded on U 140 steel profiles fixed by 100cm tent peg.
    -The calculation of roof-structures up to 100x100m span and an additional dead load of 1.5 kN/m² can be realised by 450 x 450mm profiles of laminated wooden beams.
    -There was a good exchange between us during the detail design of the structure and the creation of static calculation model.

    For more Information:[...]
    (only in german)

  • 1. drape (Aug 20, 2010 00.48):

    Great project! I teach digital fabrication and have some questions for you:

    - Which "calculating program" did you use?
    - What does the connection detail between members look like?
    - What kind of CNC machine did you use?
    - How did you coordinate CNC capabilities with detail design?
    - What kind of hardware did you use?
    - How did you resolve the ground condition? (what do the feet look like?)
    - Any speculation on the maximum spans you can achieve with the system?
    - Can you describe the working relationship you had with the "German Carpenter Association"? What did they learn from you? What did you learn from them?