PDA

View Full Version : back 40 bridge



Kevin Jenness
11-12-2022, 11:54 AM
We have a 40 acre woodlot on the far side of a year-round stream from our house The brook is about 30 feet bank to bank, quite low at times but raging high water at snowmelt and after the occasional toad-strangler. When we bought the place in 1986 there was the remains of a primitive bridge, unreinforced concrete abutments with rotted tree-trunk beams cast in place. My dad and I cut some new beams and pulled them into place with a neighbor's wrecker and a snatch block. With new decking we had access to get a Mighty Mite portable mill in to cut lumber for our house and eventual shop. Over the years the old bridge rotted out again and the abutments were damaged by flood and ice, and the access for timber harvests was by fording, with a hard pull out of the near side. This year we're getting a new bridge thanks to our son Miles who is a timber framer and all-around force of nature.

Miles started by digging down below the streambed and placing stacked keyed reinforced concrete "riprap" blocks back from the banks, pinned together with rebar and backfilled with stone. He had acquired two large steel beams from a house mover, 24" high with 12" flanges, one 53' and one 41' long. He had planned to cut one and lengthen the other by 6' but once the abutments were in realized they both need to be over 50', so he found another section at an amazing yard in Rutland. https://www.macsteelvt.org/ The flanges are narrower but should be sturdy enough given the span and loads. Our friend Chelsie came over to do the welding.

Yesterday we loaded the beams onto a flatbed trailer and moved them to about 30 yards from the stream. Miles walked them down to the near-side abutment and set them out as far as the excavator could manage with one end in the stream. The machine is about 9 tons and the beams over 2.5 tons so the loaded boom could extend out only about 8' beyond the tracks. Miles lowered the excavator down into the streambed and shifted the beams onto the far abutment. Climbing out wasn't so easy and he had to go a ways downstream to make it. It's amazing what he can do with this small excavator..

Once Chelsie welds some spacers in and they are pinned to the abutments, a tamarack deck will go on and enough fill will be pushed in place to make the approaches manageable. The whole affair is about 6' above the streambed and the abutments pretty well protected so it should last a while.

I have a hard time expressing how glad I am to have my son living nearby who is so capable and willing to help out. It has been a great pleasure watching him learn his trade and become who he is. We could have hired this job out but it would have been an entirely different experience. Miles' work can be seen on Instagram under vtheavytimber.
489698489699489700489701489702

Tom M King
11-12-2022, 12:33 PM
Very nice indeed! Looks like a fun project.

Jim Koepke
11-12-2022, 1:26 PM
Cool

jtk

Bill George
11-12-2022, 5:55 PM
Is your friend a pipefitter welder or an ironworker?

Kevin Jenness
11-12-2022, 6:27 PM
Is your friend a pipefitter welder or an ironworker?

He does all sorts of metal work, mainly architectural steel, some blacksmithing, sculpture and glass work as well. Complete fabrications, so to speak.

Ole Anderson
11-13-2022, 9:32 AM
Ambitious project. Please be sure to post additional pics as you install the deck.

Steve Schlumpf
11-13-2022, 9:48 AM
WOW!!! Looks like quite the ambitious project! Good luck with everything moving forward and we all look forward to additional photos! Thanks for sharing!

Jim Becker
11-13-2022, 10:25 AM
I suspect that nice steel understructure on the concrete abutments will last a lot longer than you'll ever need to worry about! Nice setup and absolutely a great way to go.

John K Jordan
11-13-2022, 11:45 AM
Very nice!
Having (or knowing people) who have the right tools and skills makes all the difference.

Please post progress and finished photos!

Larry Frank
11-13-2022, 7:20 PM
Nicely done...sounds like a piece of heaven.

Kevin Jenness
11-22-2022, 12:47 PM
Progress report

490311490313490314490315

Cross braces welded in and bolted to the concrete blocks. Now for decking and more backfill. Two more 2' x 2' x 6' blocks will be set against the beam ends on each side to dam off the fill. The beams are not quite 6' above the stream bed. A portable magnetic drill was used to drill the steel braces and a cordless hammer drill bored 8" deep into the abutments to bed the anchor bolts in epoxy.

Kevin Jenness
12-27-2022, 3:38 PM
Finished

492326492327492328492329

The main deck and wear strips are 4" tamarack and the bumpers at the outside edges hemlock, screwed down over strips of 1/2" braded polypropylene cord to inhibit rot. Two concrete blocks were set at each end against the beam ends to dam the backfill.

The deck is about 8' above the center of the stream bed which is how far we had to climb out when fording the stream. A fair bit of material was dug on site to even out the approaches on each side. We've seen the water run 4' high at times so the new beams at almost 6' should be safe from flood, but time will tell.

Ken Fitzgerald
12-27-2022, 3:53 PM
Nicely done! Congratulations! Enjoy the benefits.

John K Jordan
12-27-2022, 4:59 PM
Beautiful, excellent job! Most people who see or cross a bridge can’t imagine the incredible amount of work it takes. That’s prob the stoutest private bridge i’ve seen.

If the watershed is not excessively large the flood capacity you provided seems reasonable.

Tom M King
12-27-2022, 5:53 PM
That's probably the nicest privately owned bridge I've ever seen!

Jack Frederick
12-28-2022, 10:28 AM
Bridges are fun. Having access to the back 40? You will smile every time you go over that bridge. Nicely done and a gratifying family project.