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Cast-in-place-pipe for an "egg" sewer. (U.S.A.)

Cast-in-place-pipe for an "egg" sewer. (U.S.A.)

Cast-in-place-pipe for an "egg" sewer. (U.S.A.)

(OP)
I have a specification to design a liner for non-circular gravity flow pipe using the beam method.  There is no reference to any ASTM or other standard regarding the beam method.  Any information on this method would greatly be appreciated.

RE: Cast-in-place-pipe for an "egg" sewer. (U.S.A.)

Perhaps you mean "Steam" method.  This cures a plastic liner after pressure forms it to the inner shape of the pipe.

RE: Cast-in-place-pipe for an "egg" sewer. (U.S.A.)

(OP)
Thank you, civilperson.  The liner will be cured by steam rather than water, however, the liner thickness must first be calculated to withstand the external loading.  We spec ASTM F1216-07b for calculating the liner thickness of round pipe applications.  Non-circular pipes, such as this egg, must have the liner thickness calculated by the beam method.  My best guess of this method is that the cured liner shape will either be considered as a beam for loading or there is a simulated beam acting as a load on the shape.  I really don't know.  I do appreciate your response and I hope this clarifies my original question.

RE: Cast-in-place-pipe for an "egg" sewer. (U.S.A.)

You have to use the Wrc method that originated in England. There are two equations, one for deflection and one for buckling. If you are not very familiar with the design process, don't try to explain it in the spec. Just say you have an egg shape,giving the inside width and height. . Let the contractors bidding tell you what you need for liner thickness.  

Richard A. Cornelius, P.E.
WWW.amlinereast.com

RE: Cast-in-place-pipe for an "egg" sewer. (U.S.A.)

One other thing, we call it Cured-in-Place. Cast-in-place normally refers to concrete.

Richard A. Cornelius, P.E.
WWW.amlinereast.com

RE: Cast-in-place-pipe for an "egg" sewer. (U.S.A.)

(OP)
Bimr, thanks for the suggestion.  I checked and unfortunately it doesn't seem to apply.

Dick, the existing spec calls for liner thickness for round pipe to be provided by use of ASTM F1216 and for non-circular pipe to be provided by the beam method.  The contractor will submit his liner thickness, telling me what thickness is needed.  Before I hold him to providing the thickness, calculated by the beam method, I want to be sure I have an understanding of the method and a resource for it, should he request it.

Nice catch on the "Cast" instead of "Cured".  I think I was in holiday mode a little early, plus I have two CIP concrete projects in progress.

My in-company experts are back from vacation and are looking into this.  I'm still open for suggestions.

RE: Cast-in-place-pipe for an "egg" sewer. (U.S.A.)

Here is a design for a 64 by 42 ellipse. the formula are the same for an egg.
    Height        42.8    inches    1070    mm
    Width        64    inches    1600    mm
    Assumed Thickness (t')        1.8    inches    45    mm
    EffectiveLength (L)        60.400    inches    1510    mm
    Ht of WT above invert (H)                5.7    m
                        
Physical Properties                        
                        
    Modulus of Elasticity (Es) (Short term)            507614PSI    3500    MPa
    Modulus of Elasticity (El) (Long term)            253807PSI    1750    MPa
    R (0.5 for straight sides, 1 for curved)                1    
    Limiting Stress (Sl)            2901PSI    20    MPa
Design                        
H =     340Sl(t/L)²        (Stress)            
Rewriting                        
    t =     L (H / (340 Sl))    0.5            
                        
    t =    43.7 mm    1.721    inches        
                        
H =     236REl(t/L)    3    (Deflection)            
Rewriting                        
    t =    L (H / (236 R El ))    0.333             
                        
        36.2 mm    1.426    inches        
                        
                        
        Lining Thickness Required =    43.7 mm    1.721    inches    
                        
This will give you a good idea of the liner thickness. It is always thicker than the round equivalent pipe. But that is where i always start. Also, inthe formula there is no place for the live load or soil load. Convert them to feet of water and add to the hater head on the pipe. the liner gets thick in a hurry.                     
 

Richard A. Cornelius, P.E.
WWW.amlinereast.com

RE: Cast-in-place-pipe for an "egg" sewer. (U.S.A.)

(OP)
One more question, Dick.  In researching the WRc manual, I found that the 4th edition is the last "Sewerage Rehabilitation Manual".  It has been superceded by the on-line version and renamed, "Sewerage Risk Management".  What I want to know is if I subscribe to the new SRM, will I get what I want as far as structural design methods, to include liner thickness calcs?

I am under the impression that the old SRM was a three volume set.  Has it merged into one volume at the 4th edition?  Does the new "Sewerage Risk Management" manual include the information from the old "Sewerage Rehabilitation Manual"?

Thanks.

RE: Cast-in-place-pipe for an "egg" sewer. (U.S.A.)

I have the old manuals so I can't really say what the online version has.

Richard A. Cornelius, P.E.
WWW.amlinereast.com

RE: Cast-in-place-pipe for an "egg" sewer. (U.S.A.)

(OP)
Were the older editions multi-volume sets?

RE: Cast-in-place-pipe for an "egg" sewer. (U.S.A.)

Yes they were.  

Richard A. Cornelius, P.E.
WWW.amlinereast.com

RE: Cast-in-place-pipe for an "egg" sewer. (U.S.A.)

Here is the ASTM test method:

ASTM D790 - 07e1 Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials

1. Scope

1.1 These test methods cover the determination of flexural properties of unreinforced and reinforced plastics, including high-modulus composites and electrical insulating materials in the form of rectangular bars molded directly or cut from sheets, plates, or molded shapes. These test methods are generally applicable to both rigid and semirigid materials. However, flexural strength cannot be determined for those materials that do not break or that do not fail in the outer surface of the test specimen within the 5.0 % strain limit of these test methods. These test methods utilize a three-point loading system applied to a simply supported beam. A four-point loading system method can be found in Test Method D 6272.


ASTM F1216 - 09


ASTM F1216 - 09 Standard Practice for Rehabilitation of Existing Pipelines and Conduits by the Inversion and Curing of a Resin-Impregnated Tube
 

RE: Cast-in-place-pipe for an "egg" sewer. (U.S.A.)

F1216 is for round pipe and round pipe that is less than 10% ovality. Most people will want a design based on the Wrc(beam) method. Anything over 10% is a major risk, since it is already in failure according to most people.  

Richard A. Cornelius, P.E.
WWW.amlinereast.com

RE: Cast-in-place-pipe for an "egg" sewer. (U.S.A.)

"This paper has shown that the WRc rehabilitation design for Type I liners has serious theoretical and practical flaws. Although this paper focuses on the brick egg sewer problem the design method is applicable to circular sewers and for this case it appears that the WRc formula for
crown bending moment is in error by a factor of two."

http://www.nastt.org/store/technical_papersPDF/416.pdf

"The German code ATV-M 127-2 published in 2000 for the design of linings to rehabilitate sewers has proved as a helpful guideline to find the optimum wall thickness of any liner material, e.g. CIPP and stainless steel manchettes. Much rehabilitation work in different European countries has been performed successfully using the code."

http://www.hb.fh-muenster.de/opus/fhms/volltexte/2008/220/pdf/Falter_NoDig2008_C_1_03_corrected.pdf

http://www.nodigshow.com/2008/TrackOne.html

RE: Cast-in-place-pipe for an "egg" sewer. (U.S.A.)

However, the process that is recognized in the US for non-circular pipe and pipe more than 10% ovality is still the Wrc or beam method of design.  

Richard A. Cornelius, P.E.
WWW.amlinereast.com

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