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Assignment 2 2012Five groups to study
Compressionshortening along the axis
Tension elongation along the axis
Shear shifting across the axis
Torsion rotation about the axis
Bending curvature along the axis
‘force influences/reactions/loads’:For all to read: The value of history in the study of structures by Henri Petrowski
A: In-line forces:
Group 1: Compression
Important: don’t forget buckling
Typical ‘compression element’ in architecture: colonnade.. in humans: toes (ouch!)
The highest building in the world relies on compression in the columns against gravity loads.
(but the most important forces are the overturning forces of wind and earthquake!)
Vault building: all material in compression.
http://www.youtube.com/watch?v=ZrMbt_z14VM&feature=fvwrel
John Ochsendorf, modern formwork-free vault builder at MIT
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Tensile spiderweb-tensile structure by Frei Otto tensegrity of the human body
Observation/question:
Tension always has a compression component.. does compression always have a tension component?
The straighter the clothesline, the higher the stress..
(in this case there is an extra line to help carry the load..notice the connector..)
Compression-Tension balance
Tensegrity http://www.flickriver.com/groups/tensegrity/pool/interesting/
Full scale building shear animation
Punching Shear Maillart’s mushroom columns 1910
Shear wall behaviour in earthquakes:
http://richter.uprm.edu/~jclinton/Lectures/9/9buildings.htm
Group 4: Rotational forces: torsion
--- dis-torsion!
Torsional response to earthquake or winds
Torsional response of a building:
http://cite.iiit.ac.in/vlab/c ITe/media/eerc/Expr8/torsion6.swf
Millau Viaduct in France: Compression and bending in the support pillar and the column on top, pure tension in the cables, torsion and bending in the bridge deck.
http://www.youtube.com/watch?v=HUjAkIAuChk&feature=fvsr
Group 5. Moment related forces: bending
Images above taken from Petroski
Cartagena building: note holes in beams Cartagena building: Very solid foundation structure
Buckling of the web of I beams that were weakened by a test fire.
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Assignment 2 2012
5 groups of students..
1. Research your force-phenomenon in depth by researching and documenting structures/buildings and by producing sketches, diagrams and maybe animations that explain the phenomenon.
a. give historical examples.
b. give examples of the force-phenomenon in different materials.
c. give examples of special joints and methods to deal with ‘your’ force-phenomenon.
2. Make : a physical model that demonstrates your particular force phenomenon in as clear a way as possible.
Every group shall prepare a carefully timed 20 minute presentation of their ‘force phenomenon’ to the class on Wednesday morning Oct 29.
Interesting videos:
Installation of wood floor trusses:
http://www.youtube.com/watch?v=pR_2fumGJEQ&feature=related
Maison en bois construction:
http://www.youtube.com/watch?v=WQrWdvPZhAA&feature=related
Design-construction-flaw :
http://isadikin.com/2007/11/26/designers-pitfall-2-the-deceiving-tube-joint/#more-81
an interesting use of concrete block and cantilevered concrete slabs by Frank Lloyd Wright:
http://blog.archpaper.com/wordpress/archives/45015