Slab Bridge

Last week we started this stone slab bridge. It took several trips to the stone yards to find the right piece for the bridge. It needed to be long and thick. The only one I found that seemed appropriate was 10+ feet long and five feet across. As it turns out, it was too big! They couldn’t really handle moving it at the yard and were unable to deliver it. We went to the yard and cut a foot off of it using feather and wedges. This also made the piece more in scale with the yard where it’s installed.

Old school technique for cutting stone.

We rented an excavator for the day, a 10,000 pound machine. It was strong enough to lift the stone, but not really extend it very far. Fred lifted it straight up and we pulled the truck out from under it. It was a very deliberate operation. We take great pains when moving a stone this big; everything has to be strategized. We talk a lot and work through scenarios. I think we all enjoy the process and challenges. Personal safety is a key component and doing everything we can to protect the stone from getting damaged. We moved it down the yard a few feet at a time.

The bridge slab is rigged to be hoisted from the truck by an excavator

The trickiest part of the operation was extending the stone across the stream. The excavator didn’t have the leverage to extend it fully across. We used a couple of 4″ by 4″ posts that rested on the abutments and stretched across the span. Fred would extend the stone a couple of feet and set it down on the beams. Then she’d move the excavator forward until she was right up to the stone and hoist it again, extending it a couple more feet, until it was all the way across. Then we lifted it enough to get the 4″ by 4″ posts out from under the slab.

The big slab just after being placed as a bridge

This is the slab in place but the bridge is not finished. Small retaining walls will flank the abutments and protect the structure from the rising water during a downpour.