I have a small stream in my back yard that I need to cross mostly for mowing with my RZT 50 but occasionally I need to get my Kubota B7100 across. The Kubota has a FEL and the heaviest rear attachment would be my tiller. I'm guessing the total weight would be around 2,000 lbs. My bridge will be six feet wide and twelve feet across. To span this twelve feet I am thinking of treated 2x10's spaced 12" on center with 2x6 decking. Does this sound adequate to support the tractor and implements?
Help me design a bridge for my Kubota.
- Thread starter comfun1
- Start date
85Hokie
Moderator
Staff member
Lifetime Member
Equipment
BX-25D ,PTB. Under Armor, '90&'92-B7100HST's, '06 BX1850 FEL
The wood that you mention will be fine based on what you wish to carry.
Since you will run on a 4' center more or less with the width of the tractor, you might want to place a couple of those 2x10 together @ those spots. The 12" centers are fine - but very little weight will ever be directly on the middle of the bridge.
My concern would be the abutments that this bridge will be attached to on the banks. This is where the load will be transferred and must be very strong!
Another question - will the water rise up ever? If so - I would build the bridge a little higher than the ground at either end - and then back fill on both sides, this way the bottom of the bridge is really above the "bank" of the sides. This way if water flows hard - the floor joists will not pushed by the flowing water if you understand what I mean. This way too - it is a hellva lot easier to screw the floor joists in to the headers!
I also would place solid blocking between all the floor joists too.
And unlike a "deck" - you might want to space the 2x6's a little more than normal, this way the deck does not get dirt, leaves, water to stand on it, typically with fresh lumber - most place the 2x6 tight together knowing it will shrink up some, and boy does it ! Here you might want to space out a bit, allowing all debris to pass.
I would also screw everything with 3" screws as opposed to nails, even ring shanks will pull back over time.
Many will say that you need 2x12 and what not, the cost starts to move northward quickly with them. 2x8 can be used if properly re-enforced. The doubling of the floor joist at the max weight points will drastically make the bridge stronger. Even if you tied two 2x4 on the outside of the double floor joists - this bolted sandwich would not flex much at all.
85Hokie has good advise,"Many will say that you need 2x12 and what not, the cost starts to move northward quickly with them. 2x8 can be used if properly re-enforced. The doubling of the floor joist at the max weight points will drastically make the bridge stronger. Even if you tied two 2x4 on the outside of the double floor joists - this bolted sandwich would not flex much at all."
If you want to multiply the strength of a beam build by attaching two pieces of lumber together, simply sandwich a roll of roofing tin between them. I would suggest doing this on each side right where you tractor tires would be in them.
If you want to multiply the strength of a beam build by attaching two pieces of lumber together, simply sandwich a roll of roofing tin between them. I would suggest doing this on each side right where you tractor tires would be in them.
I never thought of doubling the stringers under the tires, good idea! I have placed four railroad ties on end for my pilings.
You might want to check with your local government about permits to build over a stream, and you most likely will need to get written permission from the Army Corp of Engineers.
While state laws vary, federal law doesn't. Our church plans to build some bridges, 4 small ones, over one decent size creek and two spring branches. We have had to get permission from the Corp, get plans approved by the county, and at that, the bridges have to have the abutments 3 feet back from the bank on each side to meet requirements.
Most will scoff and say that it isn't necessary or worth the trouble to go through all of that for a small bridge. Just do it and don't worry about it.
We have a small horse farm, boarding enough horses to keep hay in the barn and the lights on. In other words, there are enough borders to pay expenses, but no profit. That enables my daughter to keep her horses without incurring so many personal expenses. I say all of that to say that the operation is a very small one.
We had a private environmental group, which drives around and looks for farms that operate with creeks, streams, and ponds involved, and turns them in if they believe that there are infractions. We went through a year's worth of headache, and about $15,000 worth of changes, to comply to the agriculture department's requests (manure pile too close to creek and erosion of banks due to horses entering and leaving two ditches). They were very reasonable, but as they expressed, they were stuck between reasonable practices and nosy environmental groups. It happens, these people who anonymously stick their noses into other's business, and then disappear while you try and comply.
I'm not saying that you should go through all of those hoops- I think that it is ridiculous. But, if this bridge is remotely visible from the road, do not discount the possibility that someone, someday, will turn you in. And, what we went through pales in comparison to the fines and trouble for improperly building a bridge over a creek, or ignoring the Corp. Our church was warned that if we built those bridges (we had gone through some other processes to run water and sewer under the same creeks, legally, and the bridges came up in the conversation) without complying, we would be facing fines of $10,000 per bridge.
It stinks, but we live in an age where your property is not yours to do as you please. The government, and private environmental groups, have more power over your land than you do.
While state laws vary, federal law doesn't. Our church plans to build some bridges, 4 small ones, over one decent size creek and two spring branches. We have had to get permission from the Corp, get plans approved by the county, and at that, the bridges have to have the abutments 3 feet back from the bank on each side to meet requirements.
Most will scoff and say that it isn't necessary or worth the trouble to go through all of that for a small bridge. Just do it and don't worry about it.
We have a small horse farm, boarding enough horses to keep hay in the barn and the lights on. In other words, there are enough borders to pay expenses, but no profit. That enables my daughter to keep her horses without incurring so many personal expenses. I say all of that to say that the operation is a very small one.
We had a private environmental group, which drives around and looks for farms that operate with creeks, streams, and ponds involved, and turns them in if they believe that there are infractions. We went through a year's worth of headache, and about $15,000 worth of changes, to comply to the agriculture department's requests (manure pile too close to creek and erosion of banks due to horses entering and leaving two ditches). They were very reasonable, but as they expressed, they were stuck between reasonable practices and nosy environmental groups. It happens, these people who anonymously stick their noses into other's business, and then disappear while you try and comply.
I'm not saying that you should go through all of those hoops- I think that it is ridiculous. But, if this bridge is remotely visible from the road, do not discount the possibility that someone, someday, will turn you in. And, what we went through pales in comparison to the fines and trouble for improperly building a bridge over a creek, or ignoring the Corp. Our church was warned that if we built those bridges (we had gone through some other processes to run water and sewer under the same creeks, legally, and the bridges came up in the conversation) without complying, we would be facing fines of $10,000 per bridge.
It stinks, but we live in an age where your property is not yours to do as you please. The government, and private environmental groups, have more power over your land than you do.
Last edited:
hodge, I know you only posted a warning and caution. I'm a law abiding citizen, but there comes a time to rebel with some "laws".
If I had concerns of someone reporting me adding a crossing on a creek that small, I'd hire a tree spade and plant a row of trees to block any view from nosy passerbyers!
I've got cables running across creeks much wider then that with gates and panels hanging off of to keep neighbor's floating trees from ripping out my fence. Maybe those environmentally challenged individuals could spend some time removing the blown down, rotted trees they seem concerned about.
Oh, I forgot.....I live in Kansas.
If I had concerns of someone reporting me adding a crossing on a creek that small, I'd hire a tree spade and plant a row of trees to block any view from nosy passerbyers!
I've got cables running across creeks much wider then that with gates and panels hanging off of to keep neighbor's floating trees from ripping out my fence. Maybe those environmentally challenged individuals could spend some time removing the blown down, rotted trees they seem concerned about.
Oh, I forgot.....I live in Kansas.
Last edited:
85Hokie
Moderator
Staff member
Lifetime Member
Equipment
BX-25D ,PTB. Under Armor, '90&'92-B7100HST's, '06 BX1850 FEL
"But, if this bridge is remotely visible from the road, do not discount the possibility that someone, someday, will turn you in"
aint that the truth!!!!
Hodge - you brought up some good points too!
aint that the truth!!!!
Hodge - you brought up some good points too!
Put galvanized flashing over the top of ALL of the stringers before you put on the 2x6's. Screw the 2x6's down through the flashing. You can just use the inexpensive aluminized tape but for the weight you are carrying, flashing would be tougher. This will prevent water from rain seeping in and under the deck and just staying on the top of the stringers. This is one of the reasons why most fasteners fail in wood, the moisture just keeps chewing on the wood and fasteners in that area. If you use construction adhesive on both sides, it will also help seal the wood top and flashing.
Yes, it's an extra step but it will make the bridge mostly maintenance free and last a good couple of decades longer (especially if you keep the wood sealed with oil or something).
I wouldn't worry about the ACE too much if you don't alter the waterway in any fashion. Keep your footings back from the stream banks about 2' and don't modify the banks at all. Then they can't really say much. If this makes the bridge a bit longer, just add some 2x12's on the sides of the bridge coming up about 2"-4" and they will really stiffen the structure and let you run a little more distance without much hassle.
Just as an aside, you might want to check with some local demolition companies and see if they will let you have some I-beams from some torn down site. You can get them for the cost of scrap.
Yes, it's an extra step but it will make the bridge mostly maintenance free and last a good couple of decades longer (especially if you keep the wood sealed with oil or something).
I wouldn't worry about the ACE too much if you don't alter the waterway in any fashion. Keep your footings back from the stream banks about 2' and don't modify the banks at all. Then they can't really say much. If this makes the bridge a bit longer, just add some 2x12's on the sides of the bridge coming up about 2"-4" and they will really stiffen the structure and let you run a little more distance without much hassle.
Just as an aside, you might want to check with some local demolition companies and see if they will let you have some I-beams from some torn down site. You can get them for the cost of scrap.
Last edited:
bcbull378
Member
Equipment
GL3830,fel,brush hog,pallet forks,disc,gannon,auger,springtooth,plow,drag,ripper
You've probably already built your bridge but if you haven't what ever you come increase the dimensional lumber size by 25% and you should be good . I always over build no matter what it is I'm constructing . As for permits I wouldn't bother the less the local government knows the better off we are .
I just did that very thing last spring. I used 2X6 stringers, doubled up, 12" on center. Rock solid.
6' wide and 10 feet long. Ramps leading up to it are at 7.5 degrees and a little less than 48" long, over all length is about 17'
6' wide and 10 feet long. Ramps leading up to it are at 7.5 degrees and a little less than 48" long, over all length is about 17'
Attachments
85Hokie
Moderator
Staff member
Lifetime Member
Equipment
BX-25D ,PTB. Under Armor, '90&'92-B7100HST's, '06 BX1850 FEL
bcbull378
Member
Equipment
GL3830,fel,brush hog,pallet forks,disc,gannon,auger,springtooth,plow,drag,ripper
Thanks for the Kudos, fellas!
My BX25D, with the FEL fully loaded has crossed it many times. The first time I have my wife watching and she said she saw no deflection. A friend that does SolidWorks design punched in my design and told me it should be able to withstand five tons, probably five times what I'll throw at it.
Funny part is, I built the bridge with no intention of the Kubota, just a lawn tractor pulling a grossly over loaded cart.
My BX25D, with the FEL fully loaded has crossed it many times. The first time I have my wife watching and she said she saw no deflection. A friend that does SolidWorks design punched in my design and told me it should be able to withstand five tons, probably five times what I'll throw at it.
Funny part is, I built the bridge with no intention of the Kubota, just a lawn tractor pulling a grossly over loaded cart.
That is nice, even if someone saw it, theres likely no way it wouldnt comply. I want a creek like that in my yard, so nice and neat looking. Well done.
Just my thoughts here. When we bought our property 30 years ago, the first thing I had to do was put in a 10' x 20' bridge, elevated 8' over a 10' wide creek. Plenty long right?
The bridge is built solid, but that nice little creek has on occasion, during winter, turned into a raging torrent that raised the water level to nearly deck level.
Looking back, I wish it had been 30 feet long to better accommodate the water volume.
Don't underestimate the potential of that "small stream" or "little" creek when planning a bridge.
.
The bridge is built solid, but that nice little creek has on occasion, during winter, turned into a raging torrent that raised the water level to nearly deck level.
Looking back, I wish it had been 30 feet long to better accommodate the water volume.
Don't underestimate the potential of that "small stream" or "little" creek when planning a bridge.
.
Last edited:
here's another idea.
put some tar paper or flashing on your end supports.
triple up your 2x10's where the tires roll. (i use two logs for my bridges, whole or sawed square).
then put one 2x10 in the center, between your tire stringers and one each on the outside of the tire track along the edge.
lay tar paper or tree tar on top of your stringers, lapping over the edges by a inch or so.
place 2x4's or 2x6's (i like using treated 4x4's) crossways spacing them 1-1.5" apart for drainage. (2" apart for the 4x4's).
place a 2x4 across your bridge along the outside edges, as a tire safety rail.
(again i use 4x4's)
you never know when the boards are wet or icy, how far the rig will slide... this safety rail board can be used with the other designs....
then lay 2) 2x6's side by side or 2x10's, staggering the ends so that no two boards have ends in the same area. screw or bolt them down, flat on the 2x4's for your tire tracks. then you can replace the flat runners, as they weather or wear..
put some tar paper or flashing on your end supports.
triple up your 2x10's where the tires roll. (i use two logs for my bridges, whole or sawed square).
then put one 2x10 in the center, between your tire stringers and one each on the outside of the tire track along the edge.
lay tar paper or tree tar on top of your stringers, lapping over the edges by a inch or so.
place 2x4's or 2x6's (i like using treated 4x4's) crossways spacing them 1-1.5" apart for drainage. (2" apart for the 4x4's).
place a 2x4 across your bridge along the outside edges, as a tire safety rail.
(again i use 4x4's)
you never know when the boards are wet or icy, how far the rig will slide... this safety rail board can be used with the other designs....
then lay 2) 2x6's side by side or 2x10's, staggering the ends so that no two boards have ends in the same area. screw or bolt them down, flat on the 2x4's for your tire tracks. then you can replace the flat runners, as they weather or wear..
I have a bridge on my radar also. More so for my atv to cross by the kubota too for the back woods.
I have been torn with using the 2x12's Like you guys came up with (10 or 12's especially doubled up and withstand a lot of weight). But also RR ties as I have easy access to them. Although others have leaned me to the 2x12's.
But my neighbor who does construction (wells and septics) did a galvanized drain pipe and filled in around with rocks and then dirt then more rocks for the driving on. I think he did an apron and trash guards also.
So now his is just an extension of his long side driveway. That way would cost the most but no worrying about wood and washing away for the next 30 years
I have been torn with using the 2x12's Like you guys came up with (10 or 12's especially doubled up and withstand a lot of weight). But also RR ties as I have easy access to them. Although others have leaned me to the 2x12's.
But my neighbor who does construction (wells and septics) did a galvanized drain pipe and filled in around with rocks and then dirt then more rocks for the driving on. I think he did an apron and trash guards also.
So now his is just an extension of his long side driveway. That way would cost the most but no worrying about wood and washing away for the next 30 years
"no worrying about wood and washing away for the next 30 years."
This is only true if the culvert is large enough to handle the maximum flow of water or it will eventually get uncovered and wash out.
This is only true if the culvert is large enough to handle the maximum flow of water or it will eventually get uncovered and wash out.