Bentley SewerGEMS CONNECT

Bentley SewerGEMS CONNECT can automatically size conduits, set node invert elevations and determine the size of inlets to pass a design storm while meeting user-specified constraints. To use this feature: set up the model for analysis, specify which elements are to be sized and the sizes available for use in the design, indicate the constraints to be met, and set the scenario's Calculation Type (found in the calculation options) to Design as opposed to Analysis.

The detailed steps are provided below:

1. Create a Bentley SewerGEMS model with all the elements to be designed. Make initial estimates of the decision variables such as conduit size and invert elevations. Run the model to make sure that it is complete and will calculate without fatal errors.
2. Create a list of candidate conduit section sizes in the Conduit Catalog (click Components > Catalog > Conduit Catalog). These candidate conduits should have the same conduit shape and material as the pipe in the original model. There must be at least one conduit in the Conduit Catalog with the same shape (e.g. circular) and material (e.g. PVC) as the conduit being designed. While the user can construct this list manually, it is generally recommended to build it using the Import from Library command and then picking the shape and material from the list in the library, then deleting those sizes that should not be considered in design.
3. In the case of inlet sizing for catch basins, Bentley SewerGEMS can automatically design the inlet opening length for the inlet at any catch basin element in the network. However, there are three different Inlet Types in Bentley SewerGEMS : Percent Capture, Maximum Capacity and Catalog Inlet. Of these, only Catalog Inlets have a configurable opening length, therefore, in order for Bentley SewerGEMS to design opening length, the Inlet Type must be set to Catalog Inlet, and an Inlet must be selected. It may be necessary to add a new inlet to Inlet Catalog (click Components > Catalog > Inlet Catalog), or import one or more from the Engineering Libraries. Bentley SewerGEMS will select an opening length for a particular inlet from the list of Design Lengths associated with that inlet in the Inlet Catalog. The Design Lengths may be viewed or edited by clicking on the Design tab in the Inlet Catalog. The design algorithm will determine the minimum available inlet length that meets the design constraints. Bentley SewerGEMS will not select a different Catalog Inlet during the design run, it will only select a different opening length for the inlet specified.
4. Go to the Design Alternative (click Home > Alternatives) and set up the options for the run. There are three decisions that need to be made for conduits in terms of which properties should be adjusted during design: Design Conduit?, Design Start Invert?, and Design End Invert?. Checking any of these boxes means that these properties will be adjusted during design. ("Design Conduits" means the software should determine the size of the conduit.) Unchecking them means that the values set in the initial model will be maintained. For nodes, the choices are: Design Structure Elevations? and Allow Drop Structure?. If you do not want to the Start (Upstream) and/or Stop (Downstream) invert elevations to change during the design, you must set the Design Start Invert? and/or Design Stop Invert? property to False. For catch basin inlets, the choice is Design Inlet Opening?
5. Next set up the design constraints. For conduits, if you pick Simple as the type, the Minimum and Maximum Velocity need to be specified (or the defaults kept). If Table is selected, you can vary the constraints based on pipe Rise. If you do not want to use velocity constraints, set the Minimum to zero and Maximum to a large number. For inverts, decide whether to match Inverts or Crowns or specify an offset through the structure. For inlets, specify the Maximum Spread in Sag and the maximum Depth in Sag. If you set up constraints under Default Design Constraints (click Analysis > Default Design Constraints), these constraints will be used for any new Design Alternative as well as the alternative associated with the current scenario.

You can modify the constraints for just an individual element by checking Specify Local Pipe (Inlet) Constraints box associated with that element.

1. You can specify some additional options under the Extended Design portion of the alternative manager. In some cases, the pipes must be designed to carry the design flow at less than 100% full (100% Full is the default). You can check Partly Full Design and specify the design percent as either a constant (Simple) or a tabular list as a function of conduit rise. The design percentage is defined as a percentage of full depth. You can also allow for multiple parallel pipe barrels or limit the maximum section size by specifying maximum rise.
2. Create a new calculation option (click Analysis > Calculation Options) with the Calculation Type set to Design (as opposed to Analysis).
3. Create a new scenario using the desired Design Alternative and Calculation Options. Make that scenario the current scenario and start the design by picking Compute.
4. When the design starts, it will indicate the (current) Physical Alternative in which the results will be stored. If the user wants the results stored there, pick Yes. If the user wants the new design properties stored in another Physical Alternative, this is the place to specify that alternative by picking No. That Physical Alternative is associated with the current scenario.