Cast in Place Culvert
Cast in Place Culvert
(OP)
Some civil punk came up with this great idea to burry a culvert 60+ feet below finish grade and it was left up to me to design it. No big deal, I got the loads from the geotech and designed it. It looks more like a bomb shelter than a culvert, and would probably work as one too, unless it is the monsoon season. This thing is stout and heavily reinforced, but I have not put any sort of expansion or control joints in it. I really think it is fine, just let it crack. Since this is my first culvert to design, I was just wondering if anyone else has designed one of these things and if control joints are typically used. Thanks.





RE: Cast in Place Culvert
RE: Cast in Place Culvert
RE: Cast in Place Culvert
A continuous pour of 100' feet of concrete is rare, especially when it is 12 to 24" thick as may be the case for the base slab. I know that bridge decks are routinely placed in one fell swoop but they are thinner.
So if you'll wind up with a cold joint, you might as well plan for it and make it a contraction or expansion joint.
Regards,
![[pipe] pipe](https://www.tipmaster.com/images/pipe.gif)
Qshake
Eng-Tips Forums:Real Solutions for Real Problems Really Quick.
RE: Cast in Place Culvert
RE: Cast in Place Culvert
Dik
RE: Cast in Place Culvert
I agree with the no need for expansion joint, and I doubt it will be a continuous pour. So my construction joint should allow contraction? Or not not even worry about it? I was just thinking of showing a shear key and continiuing the hor. reinforcement throuh the joint. If I should allow for contraction, I would put smooth dowels in place of the hor. reinforcement. So, contraction joint or no contraction joint? Thanks.
RE: Cast in Place Culvert
RE: Cast in Place Culvert
RE: Cast in Place Culvert
Dik
RE: Cast in Place Culvert
As for the thickness, I designed it based on the geotech's loads. Without using shear reinforcement, it gets pretty thick. I'm thinkink civil person must have done one of these. He had a good guess for not much info.
RE: Cast in Place Culvert
However, I do not agree with the continuous pour, there is no way that will happen especially in the walls. Usually the walls are around 12-18" thick and with all the steel can and height of the forms can require extra attentino to consolidation of the concrete. The pour will move along slowly and there is time limits on the amoutn of time a truck can sit on site. And the worst thing you want is a horizontal cold joint in a wall.
Do everyone a favor and place the joints on 50' centers and use a waterstop (good idea by the way). The laborers and inspectors will thank you.
Regards,
![[pipe] pipe](https://www.tipmaster.com/images/pipe.gif)
Qshake
Eng-Tips Forums:Real Solutions for Real Problems Really Quick.
RE: Cast in Place Culvert
Your wall thickness estimate is right on. I am glad some of you have come up with the same sizes I did. Some of these guys around here thought I was killing it.
RE: Cast in Place Culvert
RE: Cast in Place Culvert
RE: Cast in Place Culvert
RE: Cast in Place Culvert
RE: Cast in Place Culvert
civilperson - a Con-something company may end up doing this as an alternate. Out of curiosity, how can the walls be so much thinner? Shear was controling the thickness, since I didn't use any shear reinforcement. Is shear reinforcement used in these arches?
RE: Cast in Place Culvert
RE: Cast in Place Culvert
If not, then make your construction joints into control joints. Cut out half or all of your longitudinal reinforcing at the joint and put in a waterstop. Also, your longitudinal reinforcing between joint should be a minimum of .005 of your concrete area, according to Table 7.12 of ACI 350, Code Requirements for Environmental Concrete Structures. I'd use #7@10" for 24" walls.
RE: Cast in Place Culvert
http://www.con-arch.com/
RE: Cast in Place Culvert
Why would water leak through random cracks and not through cracks at contraction joints?
RE: Cast in Place Culvert
RE: Cast in Place Culvert
A waterstop is located in the control joint.
RE: Cast in Place Culvert
RE: Cast in Place Culvert
I like your reference to ACI 350. I think it is more applicable to above ground structures or underground structures that carry contanminants though. Either way, it clearly shows your looking at other resources.
Regards,
![[pipe] pipe](https://www.tipmaster.com/images/pipe.gif)
Qshake
Eng-Tips Forums:Real Solutions for Real Problems Really Quick.
RE: Cast in Place Culvert
RE: Cast in Place Culvert
I think of a culvert as an environmental structure. In any case, ACI 350 is very concerned with preventing leaks through concrete, while ACI 318 is not. I don't know of a better reference for this situation.