Thursday, April 16, 2009

One step back. Research Approach

I looked back into the radiolarians in order to decide on a renewed approach for the dome project. Please check the image below for some key observations.

Radiolarian dome shape principles

If we want to use the dome shape for architectural purposes, it could be of interest to integrate some features in the parametric model as seen in radiolarians as well. Taking in consideration, the dead load, the gravity, and the supports,we already know that a combination of radial vertical beams in combination with rings and diagonal beams for stability will work in architecture (Geodesic dome Buckminster Fuller).
what seems interesting to me, learning from radiolarians, is: In which ways would some of their basis principles work for architectural purposes? The first option is, to take one homogenic grid and manipulate the density and the overall shape. The second option focusses on dividing the dome in horizontal strokes, devided by rings while manipulating the different grids in between.

objective: achieve a structure which is as light as possible and at the same time stiff enough to stand the load cases.

Approach option 1:
use a fixed grid structure for example the combined hexagonal en pentagonal grid. (this principle based on the buckyball/c60 molecule is considered as an optimal manner to devide a sphere into planars or straight beams). What the interesting part could be in this case, is that while optimizing the overall shape of the dome, its environment can be taken into consideration. That could be the support of the structure (straight ground, inclined ground) and the load case, focussing on wind from one main direction. An homogenic structure has a high potential of being able to be fabricated out of a limited range of prefab elements.

parameters: shape of dome, density of homogenic grid
fixed: material, grid type, constraints and load cases
criteria: lightness of structure
results: different dome shapes with certain density of grid. Optimized for a specific situation. (i.e. an inclined site at the sea side).

Approach option 2:

Taking the applications of rings in the dome as a starting point, we could divide the grid into multiple horizontal strokes, as seen in radiolarian skeletons (see image 6th example). Generate separate grids structures in between the rings. In this case its an option to design the grid based on some well known mechanical behaviours of architectural shells and domes. (i.e. small density in top, mainly vertical beams in base, etc. )

parameters: density of each grid stroke, type of grid per stroke (! GC might could exchange grid types)
fixed: material, overall shape of dome, constraints and load cases.
criteria: lightness of structure
results: Different combinations of grid configurations within one dome shape.

I will do some more research of dome structures and discuss it with my tutors Peter and Michela, in order to decide.