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Marble floors

April 17, 2012, 6:27 am
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As you enter a place
and walk through the door
there’s nothing says ‘grace’
like a fine marble floor.

Plain marble block or travertine,
swirling patterns, or just buff
subtle colors, mauve and green
a marble floor is quite enough.

Rugs will wear, wood will rot so
go with stone, colored designs
finely done smooth terrazzo
by skilled hands and artful minds.

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Lethargy

April 17, 2012, 8:58 pm
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I'm supposed to write
a poem and I don't
want to.
It doesn't even rhyme you lazy mason.
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The strong axis

April 19, 2012, 7:28 am
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When concrete block are made on a machine
the mix gets compacted in the vertical direction
consolidation in this axis is seen
as the strongest axis upon inspection.

This means the weaker axis is horizontal
and not nearly as strong as it could be
if the block is hit on the side it’s not long ‘til
it breaks and crumbles from flying debris.

Like things will fly in a tornado
will poke holes in regular block
and they will crush like a tomato
what seemed strong is quite a shock.

But if you use my block design
the stronger axis faces out
flying debris? Pay no mind
your building’s safer and more stout.


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Lunes

April 20, 2012, 5:01 pm
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A masonry dome can be seen
as a series of half arches
each across its opposite lean
in and support their largeness.

The dome is like an orange peel
into sections called ‘lunes’
each is heavy though they feel
as light as macaroons.

But at the bottom of the dome
the walls must get thicker
or else cracks start and roam
and spread and crack quicker.


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Cement's toll

April 21, 2012, 6:22 am
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Cement is made by heating mixes
of rock and argillaceous earth
until it forms klinker which is
ground up into cement’s worth.

But making cement is rather sad
because it makes pollution too
the extra output is pretty bad:
way too much more CO2.

Cement made wet will slowly cure
and form hydration products
reabsorbs CO2 for
making chemistry’s odd ducks.

But greener types of cement
are on the near horizon
money for more research is spent
is money that’s spent wise on.
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Nothing new

April 22, 2012, 10:04 am
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When I began to innovate
with masonry and its design
I began to contemplate
bold new thoughts seemed in line

But my experience has taught me
there is nothing ever new
my hard experiences brought me
to a realization that a few


people seem to appreciate
what I now know is true
if you stop and contemplate
there is nothing ever new.

A cathedral or an ancient church
epochs and eons older than most
are examined to see how they work
and consult their wandering ghosts.

There is nothing ever new
is what my learning has gotten
there is only that a few
things have been forgotten.


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Cozy

April 23, 2012, 7:36 am
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If you live where I live
then you know how it goes
sometimes April or May give
more of winter’s snows.

But living in a concrete home
can be pretty neat
the efficiency of a block dome
with a masonry stove for heat.

It doesn’t matter which your
preference is for a house
below is today’s picture
and I’m cozy as a mouse.
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Excavation by denomination

April 24, 2012, 7:32 am
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Way back when in olden days
they would build masonry domes
and for support, in a number of ways
they would pile up dirt to support the stones.

When the dome was complete
they’d remove all the dirt,
the dome was left: what a feat
it didn’t fall, nobody hurt

But how’d they get the dirt removed?
it surely was a lot of work
to haul it out so space improved
peasants didn’t want to shirk

responsibility to their king,
so the Lord would hide some money
in the dirt, was the thing
which peasants kept, kinda funny.
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Of Circles and Erkels

April 25, 2012, 6:14 am
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The strength of an arch is not only found
In a half circle structure over your head
It is also found deep underground
It even occurs deep under seabed.

For an arch is one of those configurations
In a circular tube in a deep long tunnel
Its strength is used to join two separate nations
Like England and France are joined by the Chunnel.

Compression still works in a completed circle
It’s pressed on itself all the way round
You needn’t be a nerd or an Erkel
To know that the arch is the strongest found.


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Fresh water and masonry

April 26, 2012, 8:07 am
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People are worried for the future
For themselves, their son or daughter
You may not have enough to suit your
Own and offspring’s need for water.

Rising seas and melting glaciers
Means there’s less than you think
The near future to face yours
Looking for good water to drink

Desalination can use the sea
To make that salty water sweet
But it takes much energy
And pollution we must beat

Far too polluting and unsustainable
So another way is sought
To make fresh water obtainable
So our best ideas are brought

And if a concrete masonry sphere
With very high compressive strength
Is sunk to depth then it is clear
It is an acceptable length

To harvest water through a filter
Using free high pressure of the deep
A concrete sphere, once I built her
To collect that filtered seep

Of freshly filtered sweet clear water
Collected for almost free
For your son or your daughter
If we should do it why can’t we?

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High and dry

April 27, 2012, 8:32 am
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Masonry arches for making roofs
Covered with timbers again and again
Proving again these basic truths
Stone stops fire, wood stops rain.

A masonry arch alone is strong
For centuries it’s not weak
Stone alone will last so long
But is all too prone to leak.

Cathedrals and churches use a roof
both inside arches made of stone
and outside wood and waterproof
Stone stops fire, dry as bone.

This old tested proven approach
Still works well, still today
Another topic for us to broach
Of thermal mass and its way

To keep a building truly warm
Helps if there is radiant heat
Stored in rock or stony form
For this to work, is a feat

Insulating the outside’s needed
For allowing radiant heat to pass
To the inside unimpeded
Bare stone inside: thermal mass.


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She's a brick. House.

April 28, 2012, 11:53 am
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When you slam the door to a wooden house

The whole thing shudders just a little

If you pound the door to see who’s home

The whole thing shakes just a little

Sounds and thumps and bumps and shivers

Reverberate and underpin a weaker state

In any wooden home or shop or store.

But a stone or brick or masonry home is

Solid as Ella Fitzgerald.
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Clerihew

April 29, 2012, 9:34 am
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Francis Straub from Pennsylvania
In 1913 had his mania.
He used cinders ‘round the clock
when he invented cinderblock.


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The last brick

April 30, 2012, 5:03 am
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Nine thousand nine hundred ninety nine brick:
This last one should do the trick.
I think it will, I think it might
I just have to place it right.


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Another Clerihew makes it 30

April 30, 2012, 7:29 pm
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Architect Christopher Wren
redesigned London when
it took a forceful maverick
from ashes hence London brick.
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No mechanism for failure

May 13, 2012, 9:45 am
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As I discussed earlier, if masonry is considered from a contemporary engineering perspective then three assumptions are made about it (none of which are actually true).  First, it is infinitely strong in compression.  Second, blocks (or voussoirs in an arch) never slide against each other, they remain in fixed position.  Third, masonry has no tensile strength.  These three assumptions are useful to the engineer in seeing how a masonry structure will respond to forces and how the structure will bear its load.

This perspective of viewing masonry leads to some interesting insight.  Of particular interest is the idea that for some arch forms there is no mechanism of collapse.  As I discussed here, masonry arches collapse from hinges being formed at the intrados and/or extrados of an arch; where the catenary thrust force line either touches or exits either the intrados or the extrados.

As discussed by Jacques Heyman in his book The Stone Skeleton (Cambridge University Press, 1995) by applying the 3 assumptions of engineering for masonry with the arch forms shown below, a hinge cannot be formed; buckling cannot happen and a mechanism for collapse does not exist.  Of these arch forms, a unique application is that of the flying arch buttress.   While Heyman notes "in passing" that this is the case and assigns little significance to the phenomenon (p.19), it seems quite significant and noteworthy to me.


A flying arch buttress cannot fail; something else has to fail for the buttress to fail.  For example, in any known case of a collapsing cathedral flying buttress, it was either due to settling of soft ground at the foundation, or repeated lightning strikes.  No fault of the flying arch, which has no mechanism for failure. 

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Rainwater storage tank: video update

June 14, 2012, 8:30 am
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Here's a short video to show the status of a masonry water storage tank prototype I've been working on.  The tank was made from manufactured concrete block which I designed and had produced on a standard concrete block machine.   This will serve as a "plunging tank" to cool off after taking the sauna.  The same idea will be used to collect potable drinking water.
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First forced-air wood kiln firing

July 3, 2012, 6:49 am
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Earlier on this blog I wrote about a kiln I designed and built, here and here.



Yesterday I fired this kiln as a forced-air (with blower) for the first time, using my improvised firebox.



It worked incredibly well.  I have never fired an easier, faster more efficient wood kiln.  What normally takes 3 days was done in less than 8 hours.  It took less than a face cord of firewood to reach temperature (~1,800 F, bisque firing).  It normally takes around 5 - 10 times that much wood.


I used a Ward burner, hooked up to propane to candle the start-up.  After It had warmed up to around 350 degrees F, I lit the wood and turned off the propane.  The blower from the burner provided the forced air.



Here's a short video showing me stoking the kiln.  It is burning just wood (no propane).
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Evolution of a block design

July 11, 2012, 10:26 am
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A new engineering model for a new block

July 17, 2012, 5:46 pm
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Contemporary engineering analysis of masonry arches provides a model which is not adequate for analysis of the masonry system I’ve been describing on this blog (dual inverse mirror plane, or ‘dimp’).  A new model is required to analyze this triangular interlocking system, which I shall attempt to describe.

The currently accepted engineering model makes three assumptions about masonry arches.   (1)  Masonry units have no tensile strength (2) Masonry units are infinitely strong (3) Blocks (or voussoirs) never slide against each other.  An arch modeled on these 3 assumptions is then viewed in cross section, and a catenary thrust force line is imposed on the wall thickness of the arch.  If the thrust force line touches or exits the wall thickness, then a hinge is formed at that point (between two adjacent blocks or voussoirs) and the arch will buckle and collapse.  If a large force is applied to the arch, the thrust force line will eventually touch or exit the inside (intrados) or outside (extrados) of the masonry arch, and failure will result in a hinging mechanism which causes the arch to buckle and collapse.
The dimp design can employ a tensile element, like a wire or cable within the wall thickness of the block.  This feature gives the arch some tensile strength.  When a large force is applied to this arch, the tensile action of the cable or wire counters this force and keeps the imaginary thrust force line more toward the center of the arch thickness.  In addition to this tensile containment, another feature of the dimp comes in to play.
A large force applied to a dimp arch will first be contained by some of the tensile web, woven as great circle arcs.  Instead of hinges forming when the thrust force line touches the intrados or the extrados, conjugate shearing occurs (as described here).  Control joints allow block faces to slide against each other; they are actually designed to.  This deformation is a strain (movement) resulting from excessive stress (applied force).  The strain relieves the stress, and when the applied force is removed, the structure returns to its original state.  The forces which restore a deformed arch are from gravity and the tensile elements.  There is of course a limit to an applied force, beyond which a dimp arch will collapse, but it is greater than that of a conventional arch constructed from voussoirs of the same thickness.  
Thus the currently accepted method of engineering analysis for masonry arches does not appear to work for the dimp design.  First, an arch made of dimp blocks has tensile strength.  Second, the blocks move (slide) against each other.  Finally, instead of a hinging mechanism there is a conjugate shearing mechanism between blocks.  It is a whole different model.
I am currently working toward a computer model to reflect this different engineering analysis.   I hope to have it available to post here eventually. 
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