Tuesday, March 8, 2011

Bridge Over Troubled Water

Technically that's not quite right.  Troubled Bridge Over Water would be more accurate.  Or Water Under Troubled Bridge. 

Eh, I think you get the point.  Let's just cut to the pictures.

I'll start with a before.  The picture below was taken in September, 2009 just before we closed on the property.  It shows some settling, but the stone walls were intact.

And what we've got now.  First up the east side.  There's actually more stone hanging on here than I expected, but it's precarious at best.

Notice the collection of debris on the top of bridge near the upper right corner of the picture.  That debris shows the high water mark which was reached sometime around dawn last Monday.  Below is the same picture with some (ahem) high quality computer work to show the high water mark.

I was honestly surprised when the water dropped to see that some stones on the east side of the bridge do still remain.  The left side has collapsed and the right side is bulging severely, but it's better than I expected.

The west side though is much worse:

I did not take any pictures Monday morning, but the one below will give some idea of what the bridge went through last week.

That photo of the bridge was taken after a storm in the 1990s.  In it you can see that the water is nearly level with the top of the box culvert (the smoother water at the center of the picture).  Last Monday the water was about two feet higher.  It completely covered the culvert and when it came under the bridge it was under enough pressure that it shot out of the culvert about a foot above the level of the rest of the water.

Even before this flooding we knew the bridge needed attention.  The original plan was to rebuild the bridge in its original state and splitting the project into four summers - west wall first two summers and east wall the following two summers.  But after last week it's obviously time to 'make a new plan, Stan'.  (Sorry, couldn't resist another Paul Simon lyric.)  Various family members have been sharing ideas and no final decisions have been made, but the general consensus is that we need to start by removing what remains of the current stone walls.  All of the stones from the collapsed walls will need to be carried to the creek bank and stacked to be reused later.  Hopefully we can dismantle what remains of the east side of the bridge before it collapses, causing the remaining large stones to break.

After that there are two possibilities.  Assuming it's not completely out of our budget, we could remove the current bridge entirely and replace it with a precast box culvert that is larger than the current culvert.  We could then have new sidewalls built using poured concrete reinforced with rebar.  If a new culvert is as expensive as I expect it to be we could keep the current culvert (assuming it survives this spring) and simply have new side walls of poured concrete with rebar.  Either way we would then use the salvaged stone from the original bridge to rebuild stone walls in front of (and hiding) the new concrete side walls.

It dosn't take long to type that out, but the reality of the job feels much more daunting.  For now I'm limited to the mental gymnastics involved - it's still much too wet to do any work along the creek.

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