[Loch-Ruadh] Gulf War Gate
kazoflr at gmail.com
Sun Feb 10 07:24:23 PST 2008
At February's Shire Populace meeting, alternatives to the Gulf War Gate
completion were suggested. Before any work not in the approved plans takes
place on the Gate, I want everyone to please understand the way that the
Gate was designed and approved, and what changes would need to be made to
safely modify the design.
Design Consideration 1: Wind
The upper portion of the Gate structure was designed for light covering
only. This was intentionally designed this way to keep the Gate from
toppling over in moderate to high winds. In high winds, the burlap/cement
covering is designed to crack and peel off, allowing wind to pass through
the structure, leaving the wooden frame intact. Repairs can then be made to
the covering as needed. If any type of board is placed on the top structure,
these boards will hold to the frame and, if the wind is high enough, bring
the entire structure down.
Design Consideration 2: Weight
In order to keep the upper portion light, spliced 2x4's were used to span
the gap between the columns. These span joists will not support weight
greater than the burlap/cement covering without risking failure. The upper
portion is connected to the structural columns with 1/2" steel bolts. These
bolts will secure the upper portion to the columns safely. The upper portion
is constructed, however, using 2 1/2" to 4" galvanized screws. While these
screws are more than adequate for holding the framework together for the
cement/ burlap covering, they are not capable of maintaining the structural
integrity after the addition of additional boards.
Alternative Completion 1: Original Design
The gate can be completed, at least the first layer of burlap, in approx 40
man-hours. The Shire Officers agreed at January's Officer Meeting to
complete the Gate using the original design in the April/May time frame.
This was to be cleared with King's Arrow Ranch and as far as I know, there
is not any problem with this decision. All materials required for completion
have already been purchased by the Shire.
Alternative Completion 2: Modified Design - Backerboard
It was suggested at populace that the upper portion of the Gate be completed
or covered with a "backerboard" material. I have "unofficailly" consulted
with the structural engineers I work with. They have suggested that the Gate
can completed this way IF the following design change criteria are met.
1. Replace the 4 - 2x4 spliced joists with 2x8 (minimum), non-spliced
members (20' length). 2x10 joist would be preferred for the distance spanned
by the Gate. $80.00 plus shipping (freight) as this size member is only
available in this area via special order.
2. Add additional nailing braces to the upper portion to met the 16" on
center (o.c.) requirement for the backerboard as specified by the
manufacturer. This would require an addition 48 linear feet of 2x4's. $20.00
3. Backerboard is approx $9.00 for a 1/2"x3'x5' board. Approx 16 sheets
would be required. $144.00.
4. Per the manufacturer, galvanized screws are required to be used at 6" o.c.
to apply the backerboard. It was recommended to me that because of wind
loads, we use 2 1/2" screws at 3" o.c. $40 approx for a 20lb pack.
5. Lag bolts and washers to attach new frame to the columns - $50.00.
This method will add approx 500 pounds to the top of the structure. Based on
wind calculations for that region of the country, we would also need to tie
each column to a +/-3' deep anchor on both the front and rear of the gate.
The tie would need to be 3/8" twisted steel cable at a 45 degree angle from
within 12" of the top of the Gate.
Depending upon the freight costs for the 2x8's, we will need to come up with
approx $450 to modify the Gate design to use backerboard.
Alternative Completion 3: Modified Design - Plywood
Most of what is mentioned as needing to be modified in Alternative 2 above
applies to adding plywood instead of backerboard. Though the added weight
will be slightly less, the wind considerations will be the same. Instead of
2x8's, we can likely get by using 2x6's. The approx cost for this option
would be in the neighboorhood of $350.
Pan Kazimierz Złowieszczy
Lordy Lord Kaz the Sinister
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