Expansion Joint, Waterstop, and Dowel for Concrete Flume
Expansion Joint, Waterstop, and Dowel for Concrete Flume
(OP)
Hi,
I am designing a flume to carry stormwater, a cross section depiction of which is attached. We want to have an expansion joint every 20 feet to aid in removing the construction if there is ever a problem with one of the utility lines that is to be buried underneath the flume. I do not want water leaking through the expansion joints, so I want to have a waterstop in between sections. Usually in construction like this (but when it does not include the need to carry water) I include at the expansion joints some dowels to keep the alignment of the construction. The walls (and floor) of the flume are to be only 5 inches thick, and that thickness must include both the vertical and horizontal reinforcement that I am planning on having. The entire outside height of the flume, from the top of the flume walls to the bottom of the flume floor, is to be only 1 foot 1 inch (1.083 feet). So there is some uncertainty about whether or not the steel reinforcement is really even needed or not. But I am still planning on having it "just in case". Because of the thin walls of the flume, and the need for 3" clearance to each unformed surface, the location of the tensile steel can not really be on the tension side of each concrete wall (the side furthest away from the backfill to go next to the wall), but will instead be on the compression side of each wall. Partly because of that, I am planning on using fiber reinforced concrete, to give slightly added strength for the whole wall, but most importantly for the tension side of each wall (which happens to be the part next to the inside walls of the flume). The question I have is whether or not there is a way to include BOTH a waterstop AND dowels at each expansion joint. The problem is that there will be very little room between the dowels and the other reinforcing (the vertical and horizontal bars). My first tendency is to think that such little room does not really negatively impact the structure because the horizontal rebar is not really providing needed strength, but instead really only providing crack control, and because the limited length of the dowels (extending to 12" into each of the adjoining concrete sections) means that only the first vertical rebar will be encroached on by the dowel, because the vertical rebar is to be #4s spaced at 12" on center. If that is the case, then it seems that the dowels can be placed without having negative effects. What do you think? And do you have any other ideas for achieving what is sought?
Thanks!
I am designing a flume to carry stormwater, a cross section depiction of which is attached. We want to have an expansion joint every 20 feet to aid in removing the construction if there is ever a problem with one of the utility lines that is to be buried underneath the flume. I do not want water leaking through the expansion joints, so I want to have a waterstop in between sections. Usually in construction like this (but when it does not include the need to carry water) I include at the expansion joints some dowels to keep the alignment of the construction. The walls (and floor) of the flume are to be only 5 inches thick, and that thickness must include both the vertical and horizontal reinforcement that I am planning on having. The entire outside height of the flume, from the top of the flume walls to the bottom of the flume floor, is to be only 1 foot 1 inch (1.083 feet). So there is some uncertainty about whether or not the steel reinforcement is really even needed or not. But I am still planning on having it "just in case". Because of the thin walls of the flume, and the need for 3" clearance to each unformed surface, the location of the tensile steel can not really be on the tension side of each concrete wall (the side furthest away from the backfill to go next to the wall), but will instead be on the compression side of each wall. Partly because of that, I am planning on using fiber reinforced concrete, to give slightly added strength for the whole wall, but most importantly for the tension side of each wall (which happens to be the part next to the inside walls of the flume). The question I have is whether or not there is a way to include BOTH a waterstop AND dowels at each expansion joint. The problem is that there will be very little room between the dowels and the other reinforcing (the vertical and horizontal bars). My first tendency is to think that such little room does not really negatively impact the structure because the horizontal rebar is not really providing needed strength, but instead really only providing crack control, and because the limited length of the dowels (extending to 12" into each of the adjoining concrete sections) means that only the first vertical rebar will be encroached on by the dowel, because the vertical rebar is to be #4s spaced at 12" on center. If that is the case, then it seems that the dowels can be placed without having negative effects. What do you think? And do you have any other ideas for achieving what is sought?
Thanks!





RE: Expansion Joint, Waterstop, and Dowel for Concrete Flume
I wouldn't worry so much about those utilities under the trench. It's only a 18 inch wide trench. Can't they work underneath it? It would probably span most utility trenches. But on the other hand I think your trench walls are too thin. I would use 8 inch thick walls, and that if there's not expansion joints. I would make the base 12 inches thick with two mats of reinforcing. As far as the grate and trench, look into Zurn http://www.zurn.com/Pages/ProductDetails.aspx?Node.... They make the whole trench, grate and frame as a unit, or just the grate and frame.
And as far as the fiber reinforcing, you could do that or you could flush money down a toilet. I'm not a believer. Just use 4000 psi concrete.
RE: Expansion Joint, Waterstop, and Dowel for Concrete Flume
RE: Expansion Joint, Waterstop, and Dowel for Concrete Flume
Regarding the difficulty in forming only 8 inches wide, thank you for pointing that out, and, yes, I am aware of that. I believe the contractor will try either one of the following. 1. Use shotcrete. 2. Use "foam" type inserts around which the concrete can be poured. 3. Pour the floor first, then place the "foam" type inserts on top of it and pour the concrete beside them.
Any thoughts on the above?
Thanks!
RE: Expansion Joint, Waterstop, and Dowel for Concrete Flume
Dik
RE: Expansion Joint, Waterstop, and Dowel for Concrete Flume
Thanks!
RE: Expansion Joint, Waterstop, and Dowel for Concrete Flume
GEOSYNTHETIC CLAY LINER (GCL)
THE INSTALLING CONTRACTOR SHALL HAVE PRIOR EXPERIENCE IN GCL INSTALLATION AND HAVE COMPETENT WORKERS AND SHALL HAVE A QUALITY CONTROL PROGRAM IN PLACE
GCL SHALL BE BENTOFIX SUPPLIED BY BENTOFIX TECHNOLOGIES INC OR APPD EQ
ALL MATERIAL SHALL BE PLACED IN ACCORDANCE WITH MANUFACTURER'S PRINTED INSTRUCTIONS
GCL ROLLS SHALL BE HANDLED, STORED AND INSTALLED WITH CARE TO PREVENT BENDING OR OTHER PHYSICAL DAMAGE
INSTALLATION SHALL UTILISE EQUIPMENT SUITABLE FOR THIS WORK
GCL MATERIAL SHALL CONSIST OF A BENTONITE MATERIAL ENCASED BY NON-WOVEN GEOTEXTILE MATERIAL AND SHALL BE NEEDLE PUNCHED AND THERMALLY LOCKED
GCL SHALL BE PLACED TO PROVIDE 6" MIN SIDE LAPS
GCL SHALL BE PLACED TO PROVIDE 12" MIN END LAPS
SUPPLEMENTAL BENTONITE SEAMING MATERIAL SHALL BE WET APPLIED AT ALL LAPPED SEAMS AND IN THE QUANTITIES RECOMMENDED BY THE MANUFACTURER. CARE SHALL BE EXERCISED TO PREVENT THE INCLUSION OF DELETERIOUS MATERIAL INTO THE SEAM ZONE
GCL SHALL BE PLACED ON A SLOPE SO THAT THE SIDE LAP SEAMS ARE PARALLEL TO THE SLOPE
GCL SHALL BE PROPERLY SECURED AT THE ANCHORAGE TRENCH USING PROPER ACCESSORIES AND CONSTRUCTION TECHNIQUES
DAMAGED GCL SHALL BE REPAIRED AS DIRECTED BY THE ENGINEER
COVER MATERIALS SHALL BE PLACED WITH CARE TO PREVENT DAMAGE TO GCL MEMBRANE
and, from the Waterstop Notes:
WATERSTOPS SHALL BE VOLCLAY WATERSTOP-RX 101 U/N, BENTONITE BASED WATERSTOP CONFORMING TO ANSI/NSF 61 OR APPD EQ
WATERSTOPS SHALL BE SECURED TO THE STRUCTURE BY VOLCLAY WB ADHESIVE OR APPD EQ
WATERSTOPS TO BE SECURED TO STRUCTURE BY A WATERBASED ADHESIVE FORMULATED FOR THIS PURPOSE
SURFACE PREPARATION AND INSTALLATION SHALL BE STRICTLY IN ACCORDANCE WITH THE MANUFACTURER'S PRINTED INSTRUCTIONS
I've used the Volclay product on over 20 projects and I assume it works... no leaks, anyway. This is a flexible 'rod' about 1/2"-3/4" dia. It is cast into a cold joint often tied to dowels in a keyway or adhered to the concrete surface. I don't have a spec for the material here, but will see if I can dig one up as well as a detail tomorrow, time permitting. I included the clay liner because it is often used for 'water' projects. The bentonite swells to form a tight 'filler' in the 'self formed void' and is very effective as an easy to install and ecologically 'friendly' waterstop. Have to be careful with some salts as the bentonite swelling is an electro chemical action caused by charges on the clay surface and water being a polar molecule. Some salts can interfere with this.
Dik
RE: Expansion Joint, Waterstop, and Dowel for Concrete Flume
RE: Expansion Joint, Waterstop, and Dowel for Concrete Flume
Dik
RE: Expansion Joint, Waterstop, and Dowel for Concrete Flume