Stiffeners for Steel Liner Penstock Transition

[Regi1989]

Hi. I am studying how to calculate for the required external stiffener of a transition (rectangular to circular) on a penstock. The penstock is buried and has an external pressure of 0.6 MPa. Internal dimension of the transition is 4mW x 4.5mH to 2m internal dimension.

I am looking at 2 cases. Case 1 is without support from the concrete, while Case 2 has support from concrete. Any idea how to calculate for the stiffener's dimension? I've got the transition plate thickness of 12mm at S235JR.

Thanks in advance for your comments.

 

[robyengIT]

Not only transition, but reducer too : that means limitation on min lenght (L=4*(D2-d1)=8 metres for concentric reducer or L=8*(D2-d1)=16 metres for eccentric reducer). AWWA C208 - ASME B&PV sec. VIII, Div I

- AISI - Steel plate engineering data vol 4

- Swanson - design of wye branches for steel pipes - Journal AWWA june 1955

- USBR nr 3 - welded steel penstock 1986

- USBR nr 32 - Stress analysis of wye branches - RUUD 1964

- structural mechanics of buried pipes chapter 18

 

[rconner]

Wow, that sounds like a whole lot of "external pressure" on a half-inch thick structure (~87 psi/12,500 psf!)