Two types of structure are
normally used: STRUCTURAL STEEL AND STRUCTURAL ALUMINIUM.
| |
STRUCTURAL
STEEL |
STRUCTURAL
ALUMINIUM |
| Minimum mechanical
specifications |
"S-275-JOH" in
accordance with UNE-EN 10219 |
6005/T6 |
| Suitable
treatment to avoid corrosion in the closed swimming-pool
environment |
HOT-DIP GALVANIZED
AT 400ºC. (This type of structure is
usually finished with two coats of paint for reasons
of aesthetics rather than protection.) |
PAINTED WITH
QUALICOAT L-425 |
| JOINTS |
At least hot-dip galvanized
fasteners, or stainless steel (but never zinc plated).
The structure must be fabricated in such a way that
all the components can be simply bolted together on
site, without the need to drill, cut, weld, or carry
out any other operation that would damage the galvanized
protection that has been applied, making it necessary
subsequently to carry out maintenance. |
STAINLESS
STEEL FASTENERS |
| Advantages
and disadvantages of each solution |
ADVANTAGES:
• Any span can be covered
• Somewhat cheaper than aluminium
DISADVANTAGES:
. Very heavy
. Fabrication takes longer
. Assembly takes longer because of the need for on-site painting
. The finish is less attractive
. Manual opening and closing is not possible |
DISADVANTAGES:
. Limited, according to design and structural
load, to maximum spans between 20 and 32 metres
. Somewhat more expensive
ADVANTAGES:
. Everything else is advantageous |
-
Both types of structure can be regarded as requiring
zero maintenance.
*All auxiliary fittings, wheels, etc., must be stainless
steel in both cases.
*The type of steel structure that is fabricated and
welded on site is not suitable for this kind of construction,
since the application of normal paintwork, no matter
how good it may be, will not obviate subsequent maintenance.
¿Who
can see corrosion in high places or hidden parts? The
only possibility of making an ungalvanized steel structure
with minimal guarantees would be to use a protection
process consisting of: sandblasting the completed structure
to Sa2.5 standard then, without subsequent handling,
and under suitable conditions of humidity, immediately
spray a first coat, and subsequently further coats (a
minimum of 4, 2 primer coats and 2 top-quality gloss).
All in all a rather difficult process and one that still
will not obviate subsequent maintenance.
EFFECTS CAUSED BY CORROSION
 |
|
 |
The structure shown in the photographs
is 17 years old, according to the proprietor. Evidently
whoever fabricated it failed to use the proper protection
system, which consists of completely fabricating
the structure so that it need only be bolted together
on site, and protecting it with hot-dip galvanization
at 400ºC. |
 |
 |
| These photographs show the state
of a structure fabricated and assembled by ACM in
Barcelona 10 years previously. It is hot-dip galvanized
and unpainted. |
|
