Tuesday, September 23, 2008

Building a Forest Bridge-Bridge Deck

With the steel superstructure nicely in place (whew!), it's time to finish the bridge. Half of the hemlock beams I ordered from a local sawmill arrived yesterday. The beams are 8" x 8" x 14' long. The ends are not cut square and they will have to each be drilled with 5 holes to accomodate the galvanized carriage bolts that will attach them to the steel superstructure. Each beam will be cut to length and temporarily set in place. The bottom of the beams will be marked through each bolt hole (in the steel beam), rolled and drilled. The beam will then be rolled back (top up), the bolts pounded through the beam, then the bolt tails will be set into the holes and the beam bolted into place. There are 26 beams.....

One week later...
The first half of the beams are in place..whew! They are too heavy to pick up alone (they are WET). They are almost too heavy to move at all. I placed them on the bridge steel with the tractor and then rolled them into place by hand. To get the overhang even on both ends, I have to bump the beams with my chest... The rest of the wood should be here at the beginning of this week.

Two weeks later....
The bridge deck is finished! The running boards were cut and nailed in place yesterday. The side rails were cut and placed but I need to locate 20" long carriage bolts to secure them to the bridge deck.

At the beginning of last week, I cut and stacked old railroad ties against the closer end of the steel and wood of the bridge so that I could backfill against them to raise the road grade to bridge level. I had to stack three ties on top of one another so the ties were drilled and 1/2" rebar pounded through them to keep the ties aligned.

To contain the fill on the sides of the ramp, I moved and stacked some very large rocks on either side leading up to the bridge. About 6 yards of gravel brought the road level about up to bridge level so that I could drive my tractor onto the bridge. With a bit of careful engineering, I placed two ramps at the other, yet to be filled, side of the bridge and got my tractor to the other side of the creek where I had to repeat the same operation to bring it to deck level.

Add a few loads of gravel to bring the road up to bridge grade and the bridge is done! I'm very happy with the way everything turned out. I was worried that a 20 ft. long, 14 ft wide bridge would look massive in this space but it ended up looking just fine. I have yet to find reasonably priced 20 inch long galvanized carriage bolts to secure the side rails to the deck. It's not a real high priority as I don't expect too much wild driving on our forest road.

2 comments:

bookworm-annie said...

I'm mighty impressed Jeffy. This is really cool.

Jeff Cleaveland said...

annie who?