Bio-Structure Bone-Inspired Building Frame by TECTONICA

Puerto Rican firm TECTONICA Architecture, in light of the devastating failure of buildings all around the world at the hands of challenging earthquake forces, has released research they have done in the immediate application of human bone structure (particularly the femur) to a new way of designing reinforced concrete frames. We published a similar project that aimed to apply bone efficiency to vehicular frames as well. More images and a exclusive interview included.

You can’t help to think of Gaudi‘s work with the overtly organic nature of the frame joints in the project, but rest assured the theory and engineering behind this projects is intact and evident. Largely based on work by Architect Wilfredo Méndez (AIT) as part of his Master of architecture thesis Principles of a Biotectonic Culture at the School of Architecture at the University of Puerto Rico, the proposal highlights the strengths in applying the structural characteristics of human bone cross section to building materials. The thesis is a structural design guide based on principles of biological adaptation for reinforced concrete morphologies. Using biomimicry as the theoretical platform, Wilfredo seeks to define structural design strategies that reduce the seismic vulnerability of RC structures, naming the proposal Stick.S (or Stick System).

We gathered this from their press release concerning the specific use of bones as a model for structural form:

” The femur is the strongest human bone and its hollow cylinder design provides maximum strength with minimum weight. Those essential features represent ideal parameters for the reduction of earthquake intensity on a building structure. In addition, the bone’s anatomy reflects the common stresses it encounters in order to adapt its morphology to its common mechanical stress. In order to achieve the bio-structural adaptation, STICK.S used hollow-shaft columns and beams whose morphology was adapted to its bending moment diagram. The resulting non-prismatic form helps the proposed frame to respond better than conventional prismatic frame to the lateral loads normally produced during an earthquake. At the other hand, the hollow-shaft parameter serves to reduce about 30 percent of reinforced concrete by structural component.”

“STICK.S becomes a custom Special Moment Resisting Frame (SMRF). Like the bones in the human skeleton, each column and beam are precisely designed according to its specific load condition and its own bending moment diagram. The hollow-shaft parameter reduces about 0.32 cubic meters (11.18 ft3) of reinforced concrete, besides it reduces 761 kg and up to 118 lbs of CO2 by structural component (column or beam). Also, because the RC frame is adapted to its common stresses by lateral loads, the deflection was greatly reduced in comparison with a conventional RC frame under same load conditions. The form, as the result of the diagram of force, directly abstracted from the bones morphology paradigm, makes the proposed frame almost 3 times stiffer than a conventional one. In further analysis, the frame base shear (seismic intensity) was greatly reduced by 35 percent.

In conclusion, because of the human skeleton parameters were adapted to the conventional structure system, which encourages the efficient concrete utilization and the building weight reduction, the building seismic vulnerability was significantly reduced, increasing its adaptation to the site characteristics. Adaptation reflects in efficiency which becomes the key to better structural performance and the building relevant sustainable output.”

As you can tell the application of the form has been very well thought out., we were successful in contacting Wilfredo and TECTONICA in an effort to shed more light on their inspirations and had this short correspondence:

BA: if you had to summarize in laymen terms, what are the chief benefits of applying the characteristics of a human bone cross section to the applications of building construction?

TEC: Bone cross section grows and transforms according to the Wolff’s Law, which implies that its anatomy reflects the common stresses it encounters (form as a diagram of force). That means that the bone tissue only grows where it’s going to be functional. So in brief terms, one of the most important benefits of the parameter translation from bone cross section morphology to the building construction is the efficient use of construction materials in fabrication or construction. This efficiency is directly translated in the form’s performance and sustainable feature.

BA: what would it take for this technology to actually be implemented, from a cost standpoint how much more expensive (or perhaps less expensive) would this system be compared to the standard or comparable methods used in earthquake prone areas today (ie. reinforced concrete skeletons or cross braced heavy moment steel frames).

TEC: Actually, this research is being developed as a proposal for the evaluation of the National Science Foundation in order to do a laboratory analysis to the proposed structural system. With the thesis development, we already do the computational analysis using RHINO, SAP2000 and ETABS, but in order to achieve a definite proposal, laboratory test is needed. Definite cost-efficiency analysis have not been made yet, however the proposal implies a reduction of almost 30 percent of reinforced concrete for each column and beam without compromising its structural resistance. This construction material savings would be translated to cost savings. In the other hand, the custom form will increase cost in comparison to conventional system. In fact what is really important is that the proposed system could actually save hundreds of thousands of dollars in retrofitting or re-construction. The proposed system does not require to change the typical form of design or construction, in fact it’s totally adaptable to the conventional building typologies. It is an evolution of the conventional post-beam system. Finally, the proposed system could be constructed in-situ or pre-fabricated.

BA: Name 5 architects or designers that you personally consistently follow and appreciate their work.
TEC: 1. Neri Oxman, 2. Cecil Balmond (Engineer), 3. Nicholas Grimshaw, 4. Jenny Sabin, 5. Alli Dryer
We would like to thank TECTONICA for sharing their resources with us and agreeing to answer our questions. Please take a look at their blog for more information.

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