Precast Sewer Structures...

[SeaMac]

Hey Eric,

I'm curious, what are you calling Con-Seal? Here we use RamNek which is used when we seal risers and cones on top of each other, we do also use a product called Con-Seal but is a coating we apply on top of all mud work, it seals out moisture. To be honest, most of our Inspectors prefer to see the RamNek oozing from the joint just to be sure we put it there in the first place.

O yeah trimming con-seal, always the last part of the mainline inspection, really sucks when you are in a 20 foot manhole hanging on with one hand and trimming with the other.

 

[buckfever]

the black tar like stuff that sticks to every thing but the concrete in the hot summer sun. We call it con-seal or a few other four letter words when it pulls the hair out of your arm. It comes in a roll that is long enough that you can make it all the way around the outer ring in one pass.

Run this stuff on the tongue and ao the groove and you will ripout the lifting lugs before you pull it back appart.

 

[SeaMac]

Hey Buckfever,

Yep, same stuff different brand name, oh yeah, it can be a b i t c h at times, we get ours in rolled stick form. It generally takes 4 sticks to go around a structure but we do use a Con-Seal product, which we apply over all mud work and all bare concrete on the exterior of a structure. It's funny different regions, different names, but all playing in the same game. Should I ever head outta here I'll have to get the local lingo low down from members.

We had a guy from California working with us a while back and when we told him we were off to set the cannons and shoot the pig he looked at us as if we were insane. Now the cannon part I could understand but shooting a pig, c'mon, doesn't everyone run a pig through new pipeline to clean out the crap?

the black tar like stuff that sticks to every thing but the concrete in the hot summer sun. We call it con-seal or a few other four letter words when it pulls the hair out of your arm. It comes in a roll that is long enough that you can make it all the way around the outer ring in one pass.

Run this stuff on the tongue and ao the groove and you will ripout the lifting lugs before you pull it back appart.

 

[CM1995]

In my area it depends on the municipality. Some will allow pre-cast inverts, some only allow brick and mortar and others only allow concrete. A few of the smaller cities you can use what you want. All sanitary structures are precast, the most common have the rubber boots installed. Some muni's allow up to 2-3 courses of brick to adjust the ring and lid and others will only allow concrete "donuts" to adjust the lid.

We always pour our storm drain inverts with concrete. Mud and brick around the pipe and box when you get a few set and depending on how many boxes you have, either pour 6-8 at a time or wait until the pipe is laid and fall back and pour them all. Concrete works good to seal around the bottom of the pipe where it enters the box since it's a pain in the arse to seal it up with brick and mortar. We commonly use square 4'x4' knock-out boxes for up to 30" pipe. Easy to handle and set, just knock out the side you need the pipe to come out of.

 

[SeaMac]

Hey CM,

I think you're the second member to say you bench and channel a storm drain, I have never once seen that done here. If they get dirty out come the Vac Trucks.

Knock-out boxes are another oddity 'round here again, never seen, heard of or set one. All of our structures are precast except the B&C being precast for sanitary and have all holes required from the yard. We do have boots for sanitary though.

It certainly makes sense to B&C drainage structures but then all those Vac Truck Driver/Operators would be out of work and you see them all the time on the road. We have one ourselves but we generally use it to excavate and sometimes "rod" a sewer line.

We always pour our storm drain inverts with concrete. We commonly use square 4'x4' knock-out boxes for up to 30" pipe. Easy to handle and set, just knock out the side you need the pipe to come out of.

 

[j.r.]

all of our storm drain manholes and inlets must have a channel. usually they are poured but the job we are on now specifies brick channels and if the manhole has more than a 5 foot drop it needs a granite channel . as far as sewer goes we usually have precast channels for the smaller pipe runs up to 15" i belive. do you guys have to tar and tape the outside joints on your sewer structures?

 

[SeaMac]

Hey j.r.,

We don't tar or tape, we use RamNek, mud the seams/joints then coat with Con-Seal.

all of our storm drain manholes and inlets must have a channel. usually they are poured but the job we are on now specifies brick channels and if the manhole has more than a 5 foot drop it needs a granite channel . as far as sewer goes we usually have precast channels for the smaller pipe runs up to 15" i belive. do you guys have to tar and tape the outside joints on your sewer structures?

 

[CM1995]

Knock-out boxes are another oddity 'round here again, never seen, heard of or set one.

This is a typical knock out box we use - http://www.foleyproducts.com/v/02_11.pdf#view=Fit

The knock outs bust pretty easy with a sledge. After you set your pipe there is a 2-3" gap from the bottom of the pipe to the bottom of the box. This gets poured with concrete, "sweeping" the concrete up to the sides to create an invert and keep any water from standing in the box. The concrete invert also seals the bottom of the pipe/box connection.

 

[SeaMac]

Hey CM,

That sure looks a lot easier to work with but again, and I'm even embarassed to keep repeating it, here in South Florida we are WOEFULLY behind the technological curve when it comes to our materials. On the bright side our Utility Project Manager appears open to new ideas that can save time and money. At present we have more work than we have manpower or iron and it's imperative that our projects be profitable in anyway possible. I keep emailing him the suggestions and links I receive in here and have been after him to join HEF. Hopefully 2013 will see some changes, hopefully that is.

I personally joined HEF with the intent to garner as much info as possible to bid on a CD&R contract which unfortunately got "bought" by a major player in the industry. Then I got tired of chasing my money doing electrical work so. If I am unable to convince others that there IS a better and more profitable way of doing things I just might have to break out on my own once again. To be honest, HEF has been a major contributor to that line of thinking too! Thanks...

This is a typical knock out box we use - http://www.foleyproducts.com/v/02_11.pdf#view=Fit

The knock outs bust pretty easy with a sledge. After you set your pipe there is a 2-3" gap from the bottom of the pipe to the bottom of the box. This gets poured with concrete, "sweeping" the concrete up to the sides to create an invert and keep any water from standing in the box. The concrete invert also seals the bottom of the pipe/box connection.

 

[buckfever]

We use knock-out boxes on occation but in some twps. they don't allow them. Let the salt eat them for a little while and put alot heavy truck traffic and it won't take long for them to fall appart.

 

[CM1995]

We use knock-out boxes on occation but in some twps. they don't allow them. Let the salt eat them for a little while and put alot heavy truck traffic and it won't take long for them to fall appart.

We don't have to worry about salt down South. Most of the applications for the knock out boxes are curb inlets that aren't exposed to traffic.

 

[digger242j]

I think you're the second member to say you bench and channel a storm drain, I have never once seen that done here. If they get dirty out come the Vac Trucks.

I wonder if that's because you have so much sandy soil that they're intended to act as a sand trap?

 

[SeaMac]

Hey Digger,

You know, I never thought of that and have yet to see it "spelled-out" in Spec's or Plan Detail's but that makes perfect sense. We do have our fair share of sand down here, don't we, seems the air is full of it these past two weeks. I just might have to email an old family friend who just happens to be a Civil Engineer, he very well could shed some light and offer clarification on the subject.

While on the subject we do wrap our drainage structure bases in Mirafi cloth before setting them, they all have a 12" dia. opening in the bottom. On this new project the City Engineers have us wrapping then bedding the RCP as well, just as if we were installing French Drain. Since we Mirafi wrap the bell & spigot of each stick we are somewhat collectively bewildered by this "new" requirement.

I wonder if that's because you have so much sandy soil that they're intended to act as a sand trap?

 

[Truck 505]

Seamac, now that you said that the structures have a 12" hole in the bottom and your not sealing the RCP when you lay it all makes sense now. What they are doing by not sealing anything up is returning the some water into the ground before it ends up wherever the pipe drains to.

In Butler Co. Ohio and probably other places what they are doing now is setting a rectangle precast box with an opening about eight inches wide and the length varies on a bed of gravel just before the catch basin. Next the box is backfilled on the outside with gravel and you fill the opening in the box with pee gravel to the the top. The box is set so the top of it is at the subgrade of the curb and then the curb is poured over top of it with the hole in the precast box formed into the flow line of the curb. After the curb sets up you pull out the forms and the opening of the precast box is now open in the flow line of the curb. You then fill the the void in the curb with porous concrete and some of the water will flow down through the porous concrete into and through the box under the curb through the gravel bed and back into the ground.

 

[CM1995]

Since we Mirafi wrap the bell & spigot of each stick we are somewhat collectively bewildered by this "new" requirement.

On the last storm project I did, the inspector wanted us to bull tar the joints. We were using gaskets and I asked him if we could use fabric in addition to the gaskets but he wanted the joints tarred too.:beatsme He said his concern with using fabric was that the fabric would allow the silty particles of the soil to washout or infiltrate the storm pipe, creating a washout around the pipe. Personally I think he has his head up his arse but what do I know?

If you use gaskets on the RCP and bell it up properly, there really isn't any chance of soil migrating into the pipe, much less creating a washout.

 

[SeaMac]

Hey Truck,

Oh we seal our RCP, first with a well greased gasket then Mirafi wrap the joint for silt intrusion. Our drainage structures unless a control box are always round with that 12" cored hole in the base. When we do bedding it's a minimum of 12" of 57 stone under the structure then at least 6" under the RCP up to the springline. As I said, we also Mirafi wrap the exterior of the structures base before setting.

Seamac, now that you said that the structures have a 12" hole in the bottom and your not sealing the RCP when you lay it all makes sense now. What they are doing by not sealing anything up is returning the some water into the ground before it ends up wherever the pipe drains to.

 

[SeaMac]

Hey CM,

I have to agree, sounds like your 'Spector has it way up there too, probably dark, smelly and scary. I have uncovered a lot of drainage pipe and have yet to see any washouts, with the ground water and high water table we contend that's a problem we surely would have dealt with before. When we home our RCP we always offset the choker and give the pipe a little spin, before sending'er home. Never had a problem doing it this way and have never had one come "un-homed".

You should invite your Inspector to join your crew and help out with the "bulling" I think that would convince him otherwise. We're not Roofers dammit, we lay pipe.

On the last storm project I did, the inspector wanted us to bull tar the joints. We were using gaskets and I asked him if we could use fabric in addition to the gaskets but he wanted the joints tarred too.:beatsme He said his concern with using fabric was that the fabric would allow the silty particles of the soil to washout or infiltrate the storm pipe, creating a washout around the pipe. Personally I think he has his head up his arse but what do I know?

If you use gaskets on the RCP and bell it up properly, there really isn't any chance of soil migrating into the pipe, much less creating a washout.

 

[Truck 505]

I found it odd not to seal the bells. I thought the wrap was to prevent infiltration since i didn't think you were sealing them.

What is the 12" hole in the bottom of the structure for.

 

[SeaMac]

I/we have absolutely no idea, they're always there when doing French Drain but this is RCP. It's what was in the Spec's so it's what we ordered, never done it like this before, or completely Mirafi wrapping the entire line. This must be some new hybrid French/RCP drainage system this particular City has devised to mess with our heads and it's working too, what a PITA. I can't recall EVER having to unload so much fabric, should get interesting when we start laying the 60".

What is the 12" hole in the bottom of the structure for.

 

[Truck 505]

The hole has to be to return water to the ground. I felt the same way about those curb inlets I described a few posts back. I had no idea what they were for until the inspector told me what they were for.