Crossposting - Colony Wall Loadings

> This is IMHO something more important to worry about than the
amount
> of radiation that might get in through colony walls. How much load
> can the colony walls take? How much water, dirt and buildings can
we
> put on them per square foot before chunks start pushing out. Esp
> since that dirt and water is going to go where the maximum
> acceleration from the spin is concentrated.
>
> I think that once you have answered this question the wall would
be
> pleanty thick enough, plus with the dirt and water on top, to stop
> even solar flare event radiation.

Very good question. My mind has been pondering that as well. I think
that the structural design of the habitat will have to be designed
specifically for any extraordinary structures within the the
habitat. The ground of the habitat will include dirt, small hollow
hills, lakes, forests, rivers, etc. We can probably estimate the
loading that they would place on the structure beneath them. For
multistorey buildings, all of that weight will have to be designed
for.

I've even toyed with the idea, within a cylinder habitat, of having
a building near each endcap, that has a ground floor on each of the
three land panels and each of the three buildings rise to join in
the center. The buildings would have variable gravity and join at a
minimal-g recreation center. From there, further construction could
progress along the zero-g axis. But as I've been considering this
plan, I've turned a lot of attention to the load factors that all of
that building mass would place on the ground footprint. My gut
feeling is that if these building are designed from the outset, then
the structural design of the habitat could be such as to spread the
load of the building mass.

Just think how cool it would be to go up the elevator in one
building, transfer in the zero-g lobby and go down the elevator in
another building. That lobby, having three elevator orientations,
people exiting at different angles. WOW. That would put the tourist
potential of the Empire State Building to shame.

I fear that it will be impossible to willy-nilly put up muli-storey
buildings in the habitats. Single family homes will probably be
tolerable. Office buildings - probably not.

The habitat as the ultimate planned community. When you reach plan
capacity, build a new habitat. No rezoning allowed. No increasing
densities allowed. It's built the way it's designed.

This whole issue of loading has led me to give a long hard look to
concrete construction for the habitats. Concrete can take impressive
compressive loads, but to directly addresss your question - I'm not
sure at the moment how thick the "floor" would have to be.

My seat of the pants approach for the moment is to work with the
following assumption. Six feet of concrete for the outer shell. Then
a 20 foot high service level where the mag-lev transport is, where
the light industry, shopping, offices, etc are. The interior is
reserved for habitation and parks. Above the service level is
another 4 feet of concrete/dirt/lake etc. For some areas where deep
water is required, we can cut the shielding down to the minimum
required to support the weight of the water above it, i.e. 29 feet
of water, 1 foot of structure. For parks with trees and grass, 3
feet of dirt, 1 foot of concrete support. Is that enough depth for
tree roots? For densely populated city centers, the service level is
minimized and much of that volume is consumed by thick concrete
support structures, effectively giving up to 30 feet of concrete
below the taller structures.

Hope that helps your thinking.