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Given the cost and the transitory nature of the application, I defied OSHA and used old electrical wire, whose internal insulation had been heat compromised. It worked well, until after the rain got it wet, and then it shorted out. The fireworks were exciting, at least for awhile, but interestingly enough, the current flow was not sufficient to trip a 70 amp circuit breaker!!?! After a couple of false starts, I compensated by tying all three wires inside this insulation together and using them as a single wire. It worked, but OSHA would not have been pleased... |
| The carport was progressing nicely until the point where we had three of the six pieced of sheet metal in place, but then came to a screeching halt. It's not really obvious from this angle, but... |
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...water puddled on it! That means that there are points in the center of the span that are lower than the bottom end. The result is that (if left as is) the sheet metal would rust out in 3 to 5 years. |
| Even more obvious here. I tried to use a 6 inch drop in 20 feet of span, and it just wasn't enough. Jim Smith suggested (after the fact) that the standard drop is 3 inches in every 12 inches. |
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There were several ways to "fix" this egreous oversight. One would have been to return to the perforated braces that support the metal skin of the roof, and add material on top of them. Metal drywall studs come to mind as a something that might work as an elevating block. There are ten strips of perforated angle, each 18 feet in length, requiring 180 feet of whatever "elevating material" we use. Cutting it to the desired thickness might have proven problematic... |
| A second "fix" would have been to cut the welds that hold the I-beams to the angle iron trusses. There are 7 I-beams, each of which crosses 4 trusses, for a total of 28 cuts. Some sort of elevating material could then be inserted between the truss and the I-beams. This is not a bad idea, but the final product might look kind of funny with the roof sitting 6 inches above its' supporting truss, and getting a blade in to make the cuts was not trivial... |
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A third "fix," and the one we settled on, was to cut the welds holding the trusses to the upright support pipes. The lowest four of the eight supports were cut from the pipes, slid down the poles, and then re-weld. I envisioned that the repositioning would require the use of hydraulic jacks, but it turned out that I had to pull down on the roofing to get it to hang low enought. The fly in the ointment had to do with the changes in the geometry. The outer posts were separated by 208 inches, and the roof had a slope of 6 inches. Appealing to the cosine function suggests that the angle at the south end (towards which the roof slopes) is about 1.65°, and the hypotenuse is 208.3 inches. Increasing the slope of the roof to 12 inches opened the small angle to 3.3° (doubling it), and the length of the hypotenuse increases by .1264 inches, or 3.2 mm. Unless the welds between the joist and the I beams at the north end were cut, the northern most joist would have to deform (or rotate) to make up this distance. In practice, that 3.2 mm was small enough that the deformation of the truss was not evident.
A fourth "fix" would have been to cut the upright support pipes below where the trusses attach, add (or remove) sections of pipe of varied length, and weld everything back together. Again this solution sounds simple, but it suffers from the same geometry drawbacks as the third option, and re-welding the support pipes (given they would be under tension to rotate) such that they were both straight and vertical (a condition required by the aesthetics of the edifice) would not prove to be trivial...
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| After about a day's worth of work by AJ, Nathen, and I, the roof now has a slope of about 12 inches in 18 feet, and a marble set anywhere on the roof's surface rolls off the bottom edge. It isn't pretty, but it works... |
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I have been riding my "exercise" bike (the old beat up mountain bike) during my lunch break (weather and work load permitting), and just happened to see this change in the odometer. 2000 miles doesn't seem like much, until you realize that the projected trip to La Rena's graduation (which we didn't take) was calculated (by Google maps) to be 1665 miles. |
| Laura visited form South Ameirca, and, while I couldn't get away to visit my brother Mark with them, I did get to visit Laura and Karren. This was a quick trip for her. |
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Barbara was involved in a trip to the zoo with grandchildren, but I didn't become aware of many of the details. |
| Nathen and Terre were considering the purchase of a SLR digital camera, so I lent mine to them so they could decide what features they liked and disliked. Terre returned it with the comment that she couldn't get it to take a single photo. I turned it on and took this one. Misery loves company, so I'm glad that I'm not the only one with difficulty adopting new technology. |
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I suspect we have had our last snow of the winter. I snowed all day (literally) Saturday, and Sunday morning there was 6 inches on my car (but none stuck to the ground). The second photo was taken seven hours later when I returned home from church. That was a quick exit. |
 On a closing note, I am a bit jealous. My debit card (masquerading as a credit card) took a trip to Europe (as evidenced by entries on my bank statement above), and left me home. National Express is a company whose niche is transporting people to and from Heathrow Airport in London. The bank ok'ed this transaction, but balked when the card attempted to pruchase a train ticket in Spain. In my oninion, that is pretty good security. There wasn't much money involved, and the bank chearfully refunded it (after asking only two pages of questions). After being without a debit card for 10 days, I realize again why I gave up using cash. How is one supposed to keep track of all those coins that won't buy anything? In the final analysis, the adventure ended well, but I'm still jealous I did't get to see England... |