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GVF-Convex for Pressure Sewer Preliminary Design

(Note: This is a follow up to another post I commented on but pulled out for better continuity of discussion). An engineer has been asked to develop a feasibility study for a new sewer system, which in my mind does not require evaluation and input size of pumps and wet wells as this time but merely to see line types and sizes and head requirements so that an educated guess can be used to design wet wells and pumps. The system is going to be pressure and therefore the model selected GVF-Convex as choice in solvers with Steady State Analysis for analysis type and Extreme Flow Setup to be dictated by two scenarios (10-States Peak and Average Daily). The model so far under analysis is correct for the loads assigned. Where the model is having issue is the ability to autodesign. When reviewing the lesson within SewerGEMs (that Mark provided on the thread "Trying to calculate steady state analysis") it was geared toward gravity pipe. If I go into alternatives and design, I don't get an option to select pressure pipe. Is there a way to set constraints (i.e. maximum TDH of 150' H2O, minimum velocity of 2.0 ft/sec, etc.) for pressure pipe to perform the auto design portion of the solver?
Parents
  • The automated design feature of GVF-Convex solver is for gravity pipes only. Pressure pipe sizes must be selected by the engineer.

    There is a similar forum thread, please have look at it. It explains about GVF-Convex solver in SewerCAD for pressure pipes..

    http://communities.bentley.com/products/hydraulics___hydrology/f/5925/p/60334/145213#145213

    Regards,

    Sushma Choure

    Bentley Technical Suppport

    Answer Verified By: nkg2 

Reply
  • The automated design feature of GVF-Convex solver is for gravity pipes only. Pressure pipe sizes must be selected by the engineer.

    There is a similar forum thread, please have look at it. It explains about GVF-Convex solver in SewerCAD for pressure pipes..

    http://communities.bentley.com/products/hydraulics___hydrology/f/5925/p/60334/145213#145213

    Regards,

    Sushma Choure

    Bentley Technical Suppport

    Answer Verified By: nkg2 

Children
  • Thanks for finding this thread as it gave a little more information. While I agree that engineering judgment should be used for the pressure portion, I would strongly caveat that for the auto design capabilities for the gravity lines. I hope future releases allow for automatic design of pressure lines based on certain criteria like maximum TDH allowed and marking on such a line. As my post indicated, the premise of an initial evaluation is not for final design but to get an approximation of what it would be capable of based on simple inputs (i.e. length of run, min/max elevations, initial loading, etc.). Yes I guess I can go through say a pipeline that is 2.5 miles long with total pressure of 2000 feet of water and with a standard pump that outputs middle of the curve 150 feet of water to do simple math to say that I will need approximately 14 intermediate lift stations but my wish list would have the program show either greyed out pressure junctions or triangle with exclamation marks along the pipeline showing approximate locations instead.