Thread: Building a crossover concrete water channel

Hello group,

In order to access my land plot I need cross a public concrete water channel that runs through my property some 30 meters from the road. It is a public waterway that supplies water for agriculture all year round from a nearby water reservoir.



The water channel is at ALMOST ground level on one side of the land (near the bananas trees) and raises to a bridge of almost 2 meters high as the land goes downhill.

Crossing under it is possible only for small vehicles up to 2 meters high,

In order to cross over the aqueduct, i will need to fill up an access road ( just till the bananas trees in the following picture)



the fill up will be 10m wide x 40m long x 1.5m high and will slope down nicely.
creating a road that crosses the channel and turns left between the bananas trees and the big tree in this picture joining the road that crossed under the aqueduct and continuing straight for the entire length of the plot (400m)



obviously i don't want to damage the water supply to my neighbors, so any advise on how to approach the crossover construction will be valuable.

what would you do in this case?

dig the road deeper so larger vehicles can get under

You may have to strengthen the aquaduct foundation supports on each side

What yu are talking about is basically a bridge that can handle 8 ton trucks.
Thats going to require a proper engineer and some major construction.
Is it not possible to convert a section of this aqueduct into an underground pipeline?

No Necron99, The aqueduct is a public asset and can not be messed with

My 2 cents:

It's quite easy actually, since you don't want to make a tunnel (tunnels might be difficult to keep dry too), nor convert the aquaduct the only option is to build a bridge (unless you want to reach your piece of land from the other side of the aquaduct..)

First I think you must ask yourself these questions:
-How high and long does the bridge have to be?
-What kinds of vehicles will go over the bridge (axle load and maximum loads)
-Does the appearance of the bridge have to match the bridge's surroundings? (answer is probably yes)
-How much do you want to spend on it? You have ugly bridges and "state of the art designed by Calatrava" bridges
-What material(s) do you prefer? Steel / concrete / wood or perhaps bamboo?

If it was me I would simply dig out the two to three metres under the aqueduct to allow temporary access for large vehicles during the house construction phase. You can fill it back in again when they have finished (or turn it into a small pond). There is far less chance of the vehicles damaging the aqueduct if they are going underneath it than over it, especially if the ground around where they will be crossing over it has been recently filled.

I would still fill the land to make a driveway as per your original plan, but at the crossover point add some extra support/footings under the channel. I'd then place a simple concrete slab over the channel, similar to the one your neighbours have used, as the long term solution - the premise being that once construction is completed nothing much bigger than a pickup truck will need to get to the house.

If for some reason I found the need to bring an enormous truck in at a later stage then I would, er, cross that bridge when I got to it. By then hopefully the filled land for the driveway would have hardened enough to provide proper support to be able to lay a steel sheet or the like on top of the concrete slab to help carry the weight of the truck.

Honestly I wouldn't 'tink too mutt' about the what ifs after the construction phase. It's not a big enough hole to damage a truck if in the off chance one ever does fall in, and so long as the extra footings have supported the base of the channel then repairing the channel walls should be a quick and easy job, if you ever had to do it.

Imagine what your Thai neighbours would do in the same situation: lots of smiles; people coming to look at the truck in a hole, and help getting it out; a few beers/bit of food and, for a few extra bottles of Leo, ask someone from nearby to bring a bucket of cement and repair the thing a day or two later. Everyone is happy as an impromptu party has been had, a solution has been found and life in the village soon returns to normal.

Originally Posted by aircut

it crossed my mind Dr. Andy as the most cost effective option, but in order to allow 6 or 8 wheeler in it would require a 2-3 m dig under the road level.... crossing over is an option more appealing to me... approximately how much higher would you fill in to hold the aqueduct safe under the road?



this is a picture from the "other side" looking over to the street for extra perspective

Did we solve this yet?

I'm now thinking , using the picture above, build two large sand /gravel support on both sides and build a steel frame to span the narrow gap.



If you could find some large trees?

hello group. i owe you an update.
the water channel is sitting on a land that was owned by a royal project nearby, and now handled by the cholopratan/tesaban. it cuts through my land about 3 meters width.

i could not get any permits to fill the gap or dig dipper under their land. my only viable option is to build a full blown bridge gaping between the two land plots and rising over the channel about 1 meter.

after consulting with civil engineers we elected for a steel based bridge and reinforced concrete road (25cm thick) 4 meters wide, that will span 5 meters over the channel. the bridge will stand a total load bearing of 60 tons (including the bridge weight itself)

the cost of designing, getting the permits, and construction of a gravel road to and off the bridge, including building the bridge itself of course was agreed at 280,000 baht.

how the price sounds to you? within range? good deal or way of the charts?

Left feild.
Would they tolerate temporary suspension of water, like a few minutes at a time?
I'm sure you could come up with a suspension bridge type setup that would seal and raise a section of the duct while traffic passed. it doesnt look very big.

Originally Posted by aircut

hello group. i owe you an update.
the water channel is sitting on a land that was owned by a royal project nearby, and now handled by the cholopratan/tesaban. it cuts through my land about 3 meters width.

i could not get any permits to fill the gap or dig dipper under their land. my only viable option is to build a full blown bridge gaping between the two land plots and rising over the channel about 1 meter.

after consulting with civil engineers we elected for a steel based bridge and reinforced concrete road (25cm thick) 4 meters wide, that will span 5 meters over the channel. the bridge will stand a total load bearing of 60 tons (including the bridge weight itself)

the cost of designing, getting the permits, and construction of a gravel road to and off the bridge, including building the bridge itself of course was agreed at 280,000 baht.

how the price sounds to you? within range? good deal or way of the charts?

Sounds like a huge rip off to me to be honest. Why does it have to be 4 meters wide anyway, is it going to be a 2 lane double deck bridge?

Kind of echoing Koetjeka: do you really need a bridge?

OK so it makes it easier to get trucks to where you will be building your house but Baht 280k pays for a lot of blokes and wheelbarrows. Once your house has been built you can easily drive underneath the aqueduct, 2 metres clearance is not bad and with a few well-timed blips on the throttle you'll soon dig it out another 20% or so.

One question that came to mind is whether you have the right to build a permanent structure over someone else's land? I honestly know nothing about how Thai law works in this regard (or it has to be said, in any other regard either).

I know you mentioned the 3 metre strip of land was now controlled by the tesaban, so assuming they are OK with the bridge then all should be good. The reason for concern is that it would be irritating if in years to come, having built an expensive bridge to access an expensive house, someone took a dislike to the setup.

I'm sure you've looked into it all, just thinking out loud as it were.

I'm rather hoping you do go ahead with building the bridge and sharing it on here purely for the selfish reason that it would make a good read...

Good luck - and sorry this post doesn't answer your question...

just a minor clarification. the entire aqueduct structure is very weak and looks kinda crumbling. digging and reinforcing its structure will be 1. too risky. 2. i have no legal rights to dig on public property and renovate the tesaban/cholapratan property. digging under can cause the entire structure to collapse, putting us under a law suit and way more expanses in damages and repairs.

the land is very beautiful, and investing in a good access way to the land is something that will only increase the land value substantially.

and yes, we will ask permits from the owner of the aqueduct to build a bridge over it.

i will keep updating this thread as we move forward with this part of the project.

thank you for being there, i truly appreciate your input

A redimix truck is just over 3m wide that is why it needs to be 4m. If you don't want to get any construction equipment onto the property (lot of local building is done by hand) then you could reduce to 3m, which is still wide enough for a fire truck at 2.5-ish meters. In reality the width is of secondary importance as it is the span that dictates the engineering.

Double and triple check the legal stuff, which of course you will. They'll all smile while you build it and it will be OK but should you ever decide to sell or upset the locals then...

Originally Posted by aircut

just a minor clarification. the entire aqueduct structure is very weak and looks kinda crumbling. digging and reinforcing its structure will be 1. too risky. 2. i have no legal rights to dig on public property and renovate the tesaban/cholapratan property. digging under can cause the entire structure to collapse, putting us under a law suit and way more expanses in damages and repairs.

the land is very beautiful, and investing in a good access way to the land is something that will only increase the land value substantially.

and yes, we will ask permits from the owner of the aqueduct to build a bridge over it.

i will keep updating this thread as we move forward with this part of the project.

thank you for being there, i truly appreciate your input

Just make sure you get a good civil engineer, someone who can truly calculate the construction. You don't want your bridge to collapse because the engineer made some minor mistake.
Also you want to use piles as foundation structure as the top layer of soil will never be able to bear 80 tons of weight, but I guess they'll know that too.
If you'd like you can send us/me some drawings to take a look at, both for reviewing and education of our forum users.

here is the initial drawing for the bridge

the location


the design

As a retired engineer i would recommend a 1 span bailey bridge it holds >40.000 kg

need only 4 solid foundation plates 1 x 1 m each(concrete, steel or wood)
4 bailey panels and 4 trustbeams. 4 end posts and 6 deck layers
They might be available in thailand (left from US during vietnam war)


History of the Bailey Bridge | Modular Bridges | Compact 200 | Mabey Bridge

lots of succes

I am not a civil engineer so my opinion would not count but this looks grossly overengineered to me.

SIL bought a truck..her rubber farm with two houses was on the wrong side of a seasonal klong feeding a larger klong..went to local orbitor and they subsidised the concrete pipe and infill to about 80% and organized the construction work...guess you have already spoken to local admin?
The area washed out recently and Orbitor fixed it for free within two days.
That said, the bridge costs seem rather reasonable actually..we had a approx 400m concrete steep uphill road built at 130k....

My take would be the fact they produced a CAD drawing of the bridge suggests the project is overpriced already.

Originally Posted by sjeng

As a retired engineer i would recommend a 1 span bailey bridge it holds >40.000 kg

need only 4 solid foundation plates 1 x 1 m each(concrete, steel or wood)
4 bailey panels and 4 trustbeams. 4 end posts and 6 deck layers
They might be available in thailand (left from US during vietnam war)


History of the Bailey Bridge | Modular Bridges | Compact 200 | Mabey Bridge

lots of succes

There's a great little video of how they construct Bailey Bridges on that site:

I learned something new, thanks Sjeng.

Originally Posted by VocalNeal

My take would be the fact they produced a CAD drawing of the bridge suggests the project is overpriced already.

I would not say overpriced. For a professional looking permanent solution it looks ok. But is a permanent professional looking solution what you need or want? I am sure for temporary access to the building site with trucks there would be a much cheaper solution.