The Pyramid Project
The Pyramid Project |
|
Phase 4
Phase
4 Objective:
“Build
Permanent Platform & Float"
“Phase
4 Objectives Discussed" ·
To
float a pyramid on bottles is seen by many as an engineering achievement and
this will have been promoted to aid bottle collection. The achievement is also
environmentally sound in the sense that rubbish is being recycled for a good use ·
At
the beginning of Phase 4 we have a structure that is 126 tons floating on 100 4m²rafts
that have a capacity to lift 193 tons, that is 65% utilisation of the lift ·
By
the end of Phase 4, by filling Rings 1 & 5 with bottles and preparing rings
2, 3 & 4 with Topa ready to take more bottles as they are collected, the
structure will weigh 272 tons. The lift with rings 1 & 5 (309 tons) coupled
with around 16 remaining rafts (31 tons lift) will be 340 tons, that is
apparently a lift utilisation of 80% ·
However,
when the platform structure slips into the water the Lower, underwater
Masaranduba beams become significantly lighter. This means the structure is 45.5
tons lighter (See below) and so lift utilisation is actually better at 66.7%
·
The
Phase Summary in the introduction includes the “Lift Utilisation” at the end
of each phase. This tells us how
much of the lift capacity we are using. (If it was greater than 100% the pyramid
would sink!). Note that the Lift Utilisation reaches its maximum of 83% at the
end of the project. If the 148 tons of lift locked into the Topa Safety Buffer
is included, the real Lift Utilisation is nearer 72% which is very safe.
"Phase
4 Task Summary"
"Phase 4 Task Overview" ·
In
phases 1.3, 1.6 and 1.8 we saw how the basic platform structure had been
started. (1.8 provides a good introduction) ·
The
lift of 976 tons is provided evenly across the platform base of (38.39m)² ·
The weight
distribution has been achieved with a spider-web design. The edges, centre and
the Spoke Beams are all reinforced with 5/16th inch iron angle ·
Each ring numbered
above has a different area and lift capacity:
·
Note: The “Topa+”
accounts for the area that is not available to the bottles to lift the pyramid
but that is nevertheless used by the temporary Raft base. (i.e. The pool, the
cannel, outside edges, - it’s about 16 rafts worth). ·
Note: The volume is
calculated by multiplying by the depth of 1.3m but then subtracting the volume
lost to underwater beams ·
The weight of the
pyramid mostly bears down on the edges and in a central 5 sided pyramid of
approximately 12m diameter. Calculations suggest that about the same weight is
bearing down on the centre as around the edges. ·
So, the architectural
challenge has been to create a strong platform that absorbs the lift of the
mid-area (between centre and edges) and distributes this lift to the sides and
centre evenly, where it can absorb the pyramid’s weight. If the pyramid did
not have this central structure then the job of distributing the lift to the
edges would have been much more difficult. (The central pyramid area would want
to explode upwards under the force of the bottles!)
·
Note that the spider
web pattern of beams is repeated once above the water line in 8”x6”
Masaranduba and again 1.5m below, underwater, in 7”x6” Masaranduba. The Upper Web
distributes the lift of the bottles and absorbs the weight from above, it is very
strong and reinforced with iron. All the joints are directed to respect the fact
that the bottles push on the Topa, the Topa pushes on the Spider Beams, Spider
Beams push on the Spoke Beams and finally the Spoke Beams push onto the
Pentagram and Square Base ·
The Upper Spider Beams are joined to the Spoke beams as shown below and the Spoke Beams are
joined to the edges and pentagram. The “Dovetailed Lap” joint is used with
the height of the dove side being 4”. Joints on the square base will use the
“#24: Mortised Rabbeted Oblique Scarf “ joint. Re. The “Art of Japanese
Joinery” by Kiyosi Seike. Dovetailed Lap Joinery
Paper drawing of Platform ·
The Lower Web can be
considered to be hanging off the upper web and is not as strong. It’s primary
function is to keep the bottles from shooting out the sides. There are
6”x6”x1.5m Masaranduba Uprights in between the two webs. These have dowel
pins that are designed to take vertical load should the pyramid ever land due to
drought. The diagonal uprights strengthen the sides and these are dove-tailed so
that the Lower Web can hang off of the Upper Web. You can just see these in the
photo of a drawing above ·
The Lower web is
dove-tailed in the opposite direction so that the two webs are locked together
and the inner beams are sandwiched inside. The pyramid is designed to land in
flat soft clay ·
Experimentation
of bottles in water under pressure will have been conducted. It will be known
for example how many bottles fail and if using silicon inside the screw-top
helps. Another experiment will be to find a liquid that can be dropped into the
bottles before the cap is tightened. The liquid will then turn to gas and
pressurise the bottle so that it can counter the pressure underwater and not get
crushed ·
It
will also be known the best way to package the bottles to maximise buoyancy.
(The experiments below were with a random assortment in a random array). It is
probable that the bottles will be placed evenly into big bags before being
submerged. This is to make them more manageable and to keep mud from getting
between the bottles should the pyramid have to land or get very low · Fishing net is also utilised to keep bottles from escaping out the sides
Experiments with bottles
·
Experimentation
to date has shown (altho outside of water) that a given volume filled with
random plastic bottles will trap 57.53% of this volume inside the bottles. The
experiment also yielded that 1m³ of bottles weighs 21.75kg and contains 493
random bottles. (The volume in the photo above was very carefully calculated
excluding the inner timbers of the table for example) ·
This
suggests that of the 1695m³ volume the platform provides, around 975m³ of
water is displaced. This translates to 975 tons of lift
"Phase 4 Task Details" 4.1
Bottle Collection ·
Plastic
bottles will fill the 1350m² area in ringed sections to a depth of 1.3m.
Allowing some loss due to Masaranduba structure around 1695m³ of bottles will
be used. (This is 36.9 tons of plastic bottles or around 836,000 random
bottles). A random sample was taken at the collection depot in Iquitos and is
typical with bottles ranging from the large 3.3 litre gaseous types down to the
0.5 litres. ·
All
labels are to be removed, bottles rinsed twice, pressurised with a non toxic gas
and the tops dipped in silicon before being screwed on tightly. The word
“Love” or a heart shape will be written on the side of each bottle. (Re.
Work of Japanese Dr Masaru Emoto) ·
By
Phase 4, five months into the construction, it will be necessary to have
collected 1/3rd of the bottles, that’s 12 tons. The Iquitos bottle
recycling plant recycles 10 tons of bottles per month so the target of 2.4
tons/month is reasonable. This collection rate will continue until the end of
the project; (2/3rds by November 2008, the rest by April 2009) ·
It
is hoped that it is possible to get bottles donated for free over this longer
period to avoid the high cost (S/. 1.20 per KG) and to improve quality 4.2
Spider Beams ·
In
phases 1.3, 1.6 and 1.8 we saw how the basic platform structure had been
started. The edges, central pentagram and Spoke Beams are in place. During this
phase the rest of the work on the platform will be completed. Not all bottles
will have been collected to gain maximum buoyancy but enough so that the
repositioned Topa is out of the water ·
The
Spider beams create 4 solid rings around the platform. The upper beams are 6”
x 8” Masaranduba and the lower beams that are permanently in the water are 6” x
7” Masaranduba. The uprights are 6” x 6” and break the 12 spans greater
than 9.6m ·
It
is expected that adding the 64 Spider Beams and extra uprights will be a long
job because much detailed carpentry of the joints is required ·
4”x4”
diagonal uprights are added forming triangles between the upper and lower web of
all the beams (Edges, Pentagram, Spoke beams and Spider beams). These are
approximately 2m long making triangles, like mini-pyramids, every 2.65m
approximately. These massively strengthen the structure in case of landing and
ensure the lower web hangs off of the upper web. The joints are all dove-tailed
and slide in from the side with the bottles pushing against them ·
There
is currently no plan to reinforce the spider beams with either iron angular or
high tension cable 4.3
Platform Structure ·
5”
x 5” Anacaspi “Topa Support Beams” will be added as per the drawing. So
too the 4” x 4” Anacaspi “Tabla Support Beams” ·
The
nets will be added by weaving them between the 2 metre diagonal upright batons
so distinct bottle areas are formed ·
The
EN3 & ES3 section contains the band pit and so it is necessary to lower the
Topa by 0.3m in this section. The Topa will also be skimmed by 2” to make way
for tarred Masaranduba boarding. With no further boarding in the pit and with a
one metre high stage the band will have 1.5m of height clearance. The lowered
area sides are also boarded off with Masaranduba and tarred to prevent water
penetration. Buoyancy lost to the Band Pit is only 3 tons and considered
negligible in other calculations 4.4
Floating ·
Rings
1 & 5 will be filled first because these are closer to the edges where the
pyramid weight is coming down from. The other 3 rings will be filled evenly as
bottles arrive after Phase 4 ·
The
temporary Topa below will slowly be removed such that the pyramid sinks and
depends on the bottles. As more Topa is available more sections will be prepared
ready for bottles. By the end of the phase only 16 rafts will remain under the
pyramid. Bottles can be added by swimming them underwater as they are collected ·
The
20cm cap of Topa holds the bottles down but it also provides an emergency extra
buffer of 145 tons of buoyancy ·
When
the rings are full and flat bottomed, plastic may be used to stop mud from
entering from below (this is a contingency against the pyramid getting too low
in the water or even landing). This is in conjunction with the fact the bottles
are already in big bags that also combat mud. The danger is that mud gets
between the bottles gluing the structure to the riverbed as the mud dries and
adding unwanted weight to the pyramid. It is also a way of preventing fish from
getting trapped between the bottles. Generally, it is preferable that water
tends to get into the platform from higher up where mud is less likely to occur ·
In
order to allow the river to flow through the pyramid platform and keep the
swimming pool from stagnating, two underwater 14 metre pipes will connect the
pool to the East side. This is in generally in the direction of river flow and
will be complemented on the West side by the canal. The 2 pipes of 1/2m diameter
will only displace 5.5m³ of bottles and so this is considered negligible to
other calculations ·
Note
that the final skin of floor boards over the Topa is not added in this phase
|
|
|
