Monday, March 7, 2011

Bridge musings

The menagerie a couple of days ago, Spring needs to come so the grass can grow. 
Well, when the alarm went off this morning Annmarie wanted to talk about the bridge construction for the front creek.  I had it all worked out in my head, a 12 foot long four foot diameter steel culvert, I would dig out the creek and drop in about a foot of 2 inch gravel then set the culvert in and then scoop in gravel and compact it every 8-10 inches all the way up to form a path.  I would use large boulders on the outside to hold in the gravel and she had talked me in to putting a heavy duty rubber water barrier on the upstream side about one foot deep into the gravel, with a used brick walkway across the top and hand rails.  All in all a decent plan.  So this morning she asks me how I am going to keep the culvert from sinking into the mud that is the bottom of the creek.  I dug a pond three years ago with a backhoe and never hit anything but mud. I finally stopped so it didn't get too deep (then my dirt barrier washed away and the pond emptied) so she has a valid point.  We had a sinkhole up the creek and it took three bucket loads of large rocks to fill it and they are starting to disappear again.  I want to build something one time and then die before it needs to be redone again.  So we are looking at a 45 year life span for this bridge.  We discussed the need for footings again (something I was trying to avoid).  Which means I will need to pour some concrete.  Then we discussed whether to use a precast concrete arch or a half pipe of culvert that I bolt to the opposing footings then cover both those with the gravel and bricks as planned.  I am now leaning toward a new design.  I would like to pour concrete footings but have them come up high enough to hold gravel behind them.  So in effect I would put them 11 feet apart and leave a ledge on them so I could span the 12 feet (the spanning timbers would be 12 feet long).  I would use pressure treated wood that would be sitting on concrete.  I would then use cedar planks to span the 12 feet.  On each end I would still build them up with the gravel and compact it with a brick surface.  This way I would not have to try and span the whole 36 feet with timbers.  So now I need to look into how much I am going to have to reinforce the footings as they will stick up into the air about four feet and go down into the ground at least 3 feet.  Not sure how wide they need to be, a guess would be at least 10 inches.  So it is back to the drawing board.  More planning and agreeing on a plan with the wife.  This way would cut my gravel usage down to about 50 yards from 100 with the added cost of concrete and cedar planks.  Concrete is running around $165/yard delivered as of a couple of months ago.  So that is about 20 yards needed for both sides.  Ouch!  Gonna have to come up with a new plan.  Maybe those concrete road dividers that stack? I could stack four to a side, so I would only need 8 of them.  I wonder how expensive those are?  Maybe I could find some used one.  Gonna have to look into that.

I had to build a new divider for one of my nest boxes.  I had used a piece of foam insulation to separate the box.  Once the chickens figured out they could pick at the foam and tear it apart they did.  So now instead of two nest boxes I only had one.  They kept rolling the second wooden egg over into one nest only.  So I added another foam divider but used one of the wood pellet bags to cover the foam.  I didn't have a feed bag available (I had just emptied out the trash).  So we will see how long this lasts.
new divider in place
The chickens favorite nest box is the one I made out of an old Coleman cooler.  They use it more than any other nest box.  Go figure.