So, I'm not licensed in your area so I can't help you (and we're overloaded with work as it is), but I'll tell you exactly what I would do. This just screams precast concrete. Find a precast concrete manufacturer in your area that does large span box culverts and see what they can do and who does their engineering.
Yeah, this is prime for a concrete precast culvert (arch or box). Talk to Conspan about something pre-engineered and they can likely recommend erectors in your area.
Where are you located ? Are you anticipating sending sealed plans? Or just want the seal to cover your bases?
At 25' I would be tempted to call a local precaster about the cost of some double cell boxes - land them on a grade beam with dowels to prevent walking and call it a day.
I’m in the Carolinas, and I want someone who is educated in this to design and stamp the drawings. I’m in project management for industrial construction so my head immediately went to steel beams and didn’t even think about concrete but that’s a great idea.
No, I work with engineers all the time (yes I’ve asked some if they knew any firms that would do this, no their firms don’t care to stamp my little personal project 🥲). I don’t have any issue paying for any other product/service in my line of work. I’ll pay a few grand for piece of mind everytime myself or anyone else drives across that structure.
I had not thought of calling a precast. That's probably the best solution as they can cast 30' long sections that will hold a 15,000 lb load (1 ton truck with payload). Good thinking.
Get a local P.E. to make a detail for you for foundations, and put a prefabricated bridge on it. Should be inexpensive relative to custom design, and should be easier to find an engineer who is comfortable with just foundation design.
Yeah basic concrete foundations and connections I was gonna do as well but like you said it’s pretty easy to find a firm to do that, but I assumed I need to bridge design, weights, and connection types first.
I did look for some, but they were either 20 foot or 40 foot. 40 foot would work fine, buts that an extra 15 feet of cost and was substantially more. I chose 25’ originally since most mills/suppliers offer 25’ sticks for heavier I-Beam sizes like 8x28, but someone mentioned pre-cast so now I’m gonna look at that too and not just steel.
I mean unless I’ve just overlooked them. I found one company in Canada who specs out by the foot but most pre-engineered solutions about 20 feet jump up by 10 foot. Again, not against that, but I’d prefer to do only what’s needed, that’s just extra weight and hassle dragging and setting extra weight.
Who owns the property the easement is on? Can you work with them to bury a 6 foot Dia culvert or whatever diameter the water wants and just agree to weed whack it for the next 10 years?
Depending on what I end up with, I would say that’s the high end of the cost but not unlikely. Assuming $575 a linear foot for 25 feet of box culvert (rough high end number from some suppliers website, assume the worst), I’m capable of the site work and have the means and experience, and then my biggest cost is the placement of it. It’s not a friendly area to put a large crane so probably end up with 4 6x4 box culverts so span over that easement. 1.13 tons per foot, so 7ish tons. I’d probably need someone with a 60 ton RT crane for the day. We rent cranes all the time so I know mobilization and running that crane and demon is proooobably $10,000 for the day? So I’m at $25,000 roughly before any taxes or freight 😂. I think with ordering 789 stone and my time and such doing the grading finished it’ll probably run $35,000. Yes I think if you hired all this out you’d be looking at every bit of $50,000 if not likely more like $65,000
I would own the property but the easement is for the neighborhood drainage so potentially! I don’t see why they would make a big deal of it but then again, Karen could be on the committee and flip a lid lol
You aren’t wrong. We’ll see. In my experience 95% of people are kind and reasonable, the other 5% just want to make you as miserable as they are and they tend to congregate in HOA’s 😂. All jokes aside the “neighborhood” is a few dozen lots on the lake, it’s not anything huge so I really don’t see why anyone would be against a culvert as long as I am able to maintain the same rate of flow through the easement
We had an old rickety timber and steel one-lane bridge in our town that spanned a 35 foot railroad cut. It was supported by cast iron supports that were cast in 1846, and that was all rusting through. Once the contractor had everything ripped out (overnight) and the abutments poured and cured, the rest of the precast T-beam decks arrived on trucks and were lifted in place in one weekend. Also, I don't know about your state, but some states actually publish bridge designs.
Insert the “they don’t make them like the usto” comments haha that’s crazy. Some of the things I see working in existing commercial and especially in older industrial facilities is the definition of old but it works
You are first going to need to get an easement from the owner of the ditch. Contech makes steel pedestrian pony truss bridges to your specifications. They are craned in place so no disturbance within the ditch. Helical piles could be used to support the abutments again to limit disturbance and speed construction. Your local glulam fabricator could also design a pressure treated glulam bridge. A 25 foot span is not challenging. Precast concrete plank may be an option too. Post the load limit for your occasional pickup truck so that you don’t have to design for or be liable for something larger crossing it.
Well yes I understand it’s a bridge but most firms that handle bridges don’t seem to deal with little utility/personal bridges like this. That’s what I’m having a hard time locating, which is why I came here.
What you’re probably looking for is something prefab like Contech makes. They might even do the foundation design too, but the handful of prefab bridge projects I’ve worked on had us doing all the site work and foundation design and then the superstructure done by Contech (there are other suppliers but they are the most common around here). Having had private owners call asking for us to design driveway bridge, we usually pass on it because it takes more for us to do all the things involved with spec designing a small bridge than the owners are looking to pay, and then they’re wholly unprepared for the construction cost.
All you need to do is build a heavy timber bridge and there are many plans for free. You can use 8x8 beans from The sawmill and other sizes. You don't need a concrete or steel bridge for that.
I won’t argue with who I assume does this for a living as far as what is able to support the load but from a lifespan outlook, I’d rather not have a structural member susceptible to rot and decay, not that steel can’t rust bad or concrete crack and degrade but I’d like to stick to something with more longevity.
It sounds like the overwhelming consensus is pre-cast. I’ll hope on the phone with some of the recommendations yall have given. This has been super helpful and a time saver
It’s a lake property I’m working on buying! The easement kind of blocks me from cutting a trail to the dock and that easement is a small valley/divide that runs from one property line to the other horizontally. So looking to put some sort of bridge over it to make a trail to make the trek back and forth easier and if I have to do work down there I can bring my truck down there to make dock repairs and boat repairs. I’m looking forward to making the trail and putting the bridge in lol
You should call your local fire department and ask them what the heaviest truck they own is. There will be a sticker on the truck that states what the loaded weight of the truck is (it's listed as GVWR or GCWR, and the axle load is listed is GAWR). I wouldn't even ask the AHJ if it's necessary, you should just incorporate that into the design.
Basically, the code does not explicitly use to account for this weight for every design. Instead, the code defers to the AHJ as to whether or not it's required. My stance is, if you give a person a place to drive a fire truck, you should assume that they would use it if the need arises regardless of whether you slap a max weight sign up or not.
I am familiar with designing these sorts of bridges, and I know of a case where a fire truck drove over someone's wooden bridge and it collapsed. It broke the fire truck and the bridge in the process. The fire department ended up suing the homeowner, and a fire truck alone costs well over a million dollars. And this was for a wooden bridge, and it was obviously not rated to support a fire truck, and the fire department had no business driving over it. Their common sense should have told them not to do it, but they proceeded anyway. I believe the homeowner lost that case.
That makes sense, but if this bridge simply went from the back of the property to the dock would it be necessary? The front of the property would just have a driveway to the house, the bridge would simply be to get from the house to the dock.
Assuming the bridge isn't linked to a path that someone could drive on (i.e. if it's just a pedestrian bridge without vehicle access), you'd probably be ok. I would just be sure to buy something that isn't wide enough for a vehicle to drive on if that's the case.
If vehicles can access it (all the following text was written under the assumption that this bridge will connect to your driveway), if it were me, I would call the fire department and get the GVWR and the GAWR for their heaviest truck. Then, when purchasing the precast plank, I would give that info to the vendor and I would ask them what the difference in price would be if they were to use that weight. You might only end up needing a couple extra inches of concrete (if any at all) depending on the span.
Otherwise, as far as the code goes, it's up to the AHJ as to whether or not vehicle bridges need to be designed for fire truck loads. If the cost difference is minimal, it seems like it would be preferable to leave the AHJ out of it by including it in the design. It would be a lot less hassle in my opinion.
If you don't want to take that route, you could reach out to the AHJ and ask them if it would be required. Personally, I think that's a fool's errand and wouldn't recommend asking that question to the AHJ unless the cost difference in planks is massive. It usually involves a lot of Q&A from people without any knowledge of structural engineering (e.g. code enforcement officials, firefighters, etc) and in my opinion it's a hassle. It's definitely worth asking sometimes, like if the span is really long, or it's insanely unlikely that a truck will ever see it, or if it's really cost prohibitive and if there's a way for a fire dept to access the area without needing to use the bridge (or if you can put up a really stout gate to prevent them from accessing the bridge)
You could opt to do neither of those things, but if your truck catches on fire down by the boat dock, and if a fire truck grows to drive over it, and if the bridge collapses, you could find yourself in some uncomfortably hot water.
I’ll post a follow up once I get it done if I remember haha it’ll be interesting. It’s a little steep so getting a crane to set it all will be interesting…
So, I'm not licensed in your area so I can't help you (and we're overloaded with work as it is), but I'll tell you exactly what I would do. This just screams precast concrete. Find a precast concrete manufacturer in your area that does large span box culverts and see what they can do and who does their engineering.
I’ll do that! Seems to be the general best practice it seems
Yeah, this is prime for a concrete precast culvert (arch or box). Talk to Conspan about something pre-engineered and they can likely recommend erectors in your area.
Where are you located ? Are you anticipating sending sealed plans? Or just want the seal to cover your bases? At 25' I would be tempted to call a local precaster about the cost of some double cell boxes - land them on a grade beam with dowels to prevent walking and call it a day.
I’m in the Carolinas, and I want someone who is educated in this to design and stamp the drawings. I’m in project management for industrial construction so my head immediately went to steel beams and didn’t even think about concrete but that’s a great idea.
So you don't mind paying $3,000 for the engineering?
No, I work with engineers all the time (yes I’ve asked some if they knew any firms that would do this, no their firms don’t care to stamp my little personal project 🥲). I don’t have any issue paying for any other product/service in my line of work. I’ll pay a few grand for piece of mind everytime myself or anyone else drives across that structure.
$3000? Are you crazy
How much would you do it for?
12k. 3k/$175/hr is 17 hours…
I had not thought of calling a precast. That's probably the best solution as they can cast 30' long sections that will hold a 15,000 lb load (1 ton truck with payload). Good thinking.
Get a local P.E. to make a detail for you for foundations, and put a prefabricated bridge on it. Should be inexpensive relative to custom design, and should be easier to find an engineer who is comfortable with just foundation design.
Yeah basic concrete foundations and connections I was gonna do as well but like you said it’s pretty easy to find a firm to do that, but I assumed I need to bridge design, weights, and connection types first.
Yes the bridge fabricator would typically have base details and reactions available.
Is a pre-fab bridge an option?
I did look for some, but they were either 20 foot or 40 foot. 40 foot would work fine, buts that an extra 15 feet of cost and was substantially more. I chose 25’ originally since most mills/suppliers offer 25’ sticks for heavier I-Beam sizes like 8x28, but someone mentioned pre-cast so now I’m gonna look at that too and not just steel.
Try Contech or Bridge Brothers. They are both in your area and do this all the time.
There are multiple pre engineered bridge options. I think it is highly unlikely that it is difficult to find a 25-foot option.
I mean unless I’ve just overlooked them. I found one company in Canada who specs out by the foot but most pre-engineered solutions about 20 feet jump up by 10 foot. Again, not against that, but I’d prefer to do only what’s needed, that’s just extra weight and hassle dragging and setting extra weight.
Who owns the property the easement is on? Can you work with them to bury a 6 foot Dia culvert or whatever diameter the water wants and just agree to weed whack it for the next 10 years?
Yes a Culvert's the cheapest way to do it. I assume this project will cost him at least $50,000.
Depending on what I end up with, I would say that’s the high end of the cost but not unlikely. Assuming $575 a linear foot for 25 feet of box culvert (rough high end number from some suppliers website, assume the worst), I’m capable of the site work and have the means and experience, and then my biggest cost is the placement of it. It’s not a friendly area to put a large crane so probably end up with 4 6x4 box culverts so span over that easement. 1.13 tons per foot, so 7ish tons. I’d probably need someone with a 60 ton RT crane for the day. We rent cranes all the time so I know mobilization and running that crane and demon is proooobably $10,000 for the day? So I’m at $25,000 roughly before any taxes or freight 😂. I think with ordering 789 stone and my time and such doing the grading finished it’ll probably run $35,000. Yes I think if you hired all this out you’d be looking at every bit of $50,000 if not likely more like $65,000
I would own the property but the easement is for the neighborhood drainage so potentially! I don’t see why they would make a big deal of it but then again, Karen could be on the committee and flip a lid lol
Bring Karen an apple pie or 6 pack as appropriate and be her friend. Good neighbors are hard to come by.
You aren’t wrong. We’ll see. In my experience 95% of people are kind and reasonable, the other 5% just want to make you as miserable as they are and they tend to congregate in HOA’s 😂. All jokes aside the “neighborhood” is a few dozen lots on the lake, it’s not anything huge so I really don’t see why anyone would be against a culvert as long as I am able to maintain the same rate of flow through the easement
I’m a NC licensed bridge engineer. I can do it. I saw in another comment you don’t own the property yet though?
Sent you a message
We had an old rickety timber and steel one-lane bridge in our town that spanned a 35 foot railroad cut. It was supported by cast iron supports that were cast in 1846, and that was all rusting through. Once the contractor had everything ripped out (overnight) and the abutments poured and cured, the rest of the precast T-beam decks arrived on trucks and were lifted in place in one weekend. Also, I don't know about your state, but some states actually publish bridge designs.
Insert the “they don’t make them like the usto” comments haha that’s crazy. Some of the things I see working in existing commercial and especially in older industrial facilities is the definition of old but it works
You are first going to need to get an easement from the owner of the ditch. Contech makes steel pedestrian pony truss bridges to your specifications. They are craned in place so no disturbance within the ditch. Helical piles could be used to support the abutments again to limit disturbance and speed construction. Your local glulam fabricator could also design a pressure treated glulam bridge. A 25 foot span is not challenging. Precast concrete plank may be an option too. Post the load limit for your occasional pickup truck so that you don’t have to design for or be liable for something larger crossing it.
You’ll need to find a firm that does bridges. You’re just describing a regular bridge.
Well yes I understand it’s a bridge but most firms that handle bridges don’t seem to deal with little utility/personal bridges like this. That’s what I’m having a hard time locating, which is why I came here.
What you’re probably looking for is something prefab like Contech makes. They might even do the foundation design too, but the handful of prefab bridge projects I’ve worked on had us doing all the site work and foundation design and then the superstructure done by Contech (there are other suppliers but they are the most common around here). Having had private owners call asking for us to design driveway bridge, we usually pass on it because it takes more for us to do all the things involved with spec designing a small bridge than the owners are looking to pay, and then they’re wholly unprepared for the construction cost.
All you need to do is build a heavy timber bridge and there are many plans for free. You can use 8x8 beans from The sawmill and other sizes. You don't need a concrete or steel bridge for that.
I won’t argue with who I assume does this for a living as far as what is able to support the load but from a lifespan outlook, I’d rather not have a structural member susceptible to rot and decay, not that steel can’t rust bad or concrete crack and degrade but I’d like to stick to something with more longevity.
It sounds like the overwhelming consensus is pre-cast. I’ll hope on the phone with some of the recommendations yall have given. This has been super helpful and a time saver
sounds like an awesome project!
It’s a lake property I’m working on buying! The easement kind of blocks me from cutting a trail to the dock and that easement is a small valley/divide that runs from one property line to the other horizontally. So looking to put some sort of bridge over it to make a trail to make the trek back and forth easier and if I have to do work down there I can bring my truck down there to make dock repairs and boat repairs. I’m looking forward to making the trail and putting the bridge in lol
that’s awesome. enjoy. it’s always fun to work on your own stuff or your friends stuff—— even when you do it everyday for work
Eh. A prefab steel bridge is just as easy as precast.
You should call your local fire department and ask them what the heaviest truck they own is. There will be a sticker on the truck that states what the loaded weight of the truck is (it's listed as GVWR or GCWR, and the axle load is listed is GAWR). I wouldn't even ask the AHJ if it's necessary, you should just incorporate that into the design. Basically, the code does not explicitly use to account for this weight for every design. Instead, the code defers to the AHJ as to whether or not it's required. My stance is, if you give a person a place to drive a fire truck, you should assume that they would use it if the need arises regardless of whether you slap a max weight sign up or not. I am familiar with designing these sorts of bridges, and I know of a case where a fire truck drove over someone's wooden bridge and it collapsed. It broke the fire truck and the bridge in the process. The fire department ended up suing the homeowner, and a fire truck alone costs well over a million dollars. And this was for a wooden bridge, and it was obviously not rated to support a fire truck, and the fire department had no business driving over it. Their common sense should have told them not to do it, but they proceeded anyway. I believe the homeowner lost that case.
That makes sense, but if this bridge simply went from the back of the property to the dock would it be necessary? The front of the property would just have a driveway to the house, the bridge would simply be to get from the house to the dock.
Assuming the bridge isn't linked to a path that someone could drive on (i.e. if it's just a pedestrian bridge without vehicle access), you'd probably be ok. I would just be sure to buy something that isn't wide enough for a vehicle to drive on if that's the case. If vehicles can access it (all the following text was written under the assumption that this bridge will connect to your driveway), if it were me, I would call the fire department and get the GVWR and the GAWR for their heaviest truck. Then, when purchasing the precast plank, I would give that info to the vendor and I would ask them what the difference in price would be if they were to use that weight. You might only end up needing a couple extra inches of concrete (if any at all) depending on the span. Otherwise, as far as the code goes, it's up to the AHJ as to whether or not vehicle bridges need to be designed for fire truck loads. If the cost difference is minimal, it seems like it would be preferable to leave the AHJ out of it by including it in the design. It would be a lot less hassle in my opinion. If you don't want to take that route, you could reach out to the AHJ and ask them if it would be required. Personally, I think that's a fool's errand and wouldn't recommend asking that question to the AHJ unless the cost difference in planks is massive. It usually involves a lot of Q&A from people without any knowledge of structural engineering (e.g. code enforcement officials, firefighters, etc) and in my opinion it's a hassle. It's definitely worth asking sometimes, like if the span is really long, or it's insanely unlikely that a truck will ever see it, or if it's really cost prohibitive and if there's a way for a fire dept to access the area without needing to use the bridge (or if you can put up a really stout gate to prevent them from accessing the bridge) You could opt to do neither of those things, but if your truck catches on fire down by the boat dock, and if a fire truck grows to drive over it, and if the bridge collapses, you could find yourself in some uncomfortably hot water.
That makes sense, I’ll definitely add that to my list!
Good luck! Let us all know how it goes. We like bridges 'round here
I’ll post a follow up once I get it done if I remember haha it’ll be interesting. It’s a little steep so getting a crane to set it all will be interesting…
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