From Civil 3D, with Love

Transcription

1 From Civil 3D, with Love Download the zip file containing the files needed for the exercise. Extract the files to a convenient location on your hard drive before you begin. The files associated with this exercise are compatible with Autodesk Storm and Sanitary Analysis 2013 and higher. Earlier in this chapter, you saw some of the preparations that must take place before you click the Edit In Storm And Sanitary Analysis button. Once inside SSA, a few more pieces of information need to be added before SSA can do its analysis. In the following example, you will see what becomes of catchment objects and pipes once they are imported into SSA: 1. From Civil 3D, open the file C3DtoSSA.dwg (or C3dtoSSA_METRIC.dwg). 2. Select the Analyze tab Design panel and click Edit In Storm And Sanitary Analysis. 3. Verify that there is a check mark next to the STORM pipe network. 4. Click OK in the Export To Storm Sewers dialog, as shown in Figure Figure 15.34: The pipe network on its way to SSA 5. SSA launches. Click OK to create a new project. After a moment, SSA will let you know that you have successfully imported the Hydraflow Storm Sewers file. 6. Click No you do not need to save the log file. 7. At the top of the SSA window, click Plan View. Page 1 of 11

2 8. Examine the inlets and catch basins that have been imported. Notice that an offsite outfall has been added to each inlet. This is because you don t model the overland links in Civil 3D. When inlets are first imported into SSA, the program assumes they are on grade. Water that bypasses on grade inlets needs to go somewhere, so SSA automatically throws in an outfall to take care of the excess water. In the next steps you will remove the outfalls and create the overland links. 9. Right-click on the outfall that has been added to Inlet Structure-(1). 10. Click Delete, as shown in Figure Figure 15.35: Right-click and click Delete to remove the extraneous outfall. 11. Click Yes to confirm the deletion. 12. Right-click and delete the outfall to the far right. Click Yes to confirm the deletion. 13. Add overland conveyance links similar to the previous exercise: a. Add a link between Inlet Structure-(1) and Inlet Structure-(2). b. Add a link between Inlet Structure-(2) and the outfall. 14. Double-click one of the conveyance links to edit the links in tabular form. 15. Set the diameters of Pipe-(1) and Pipe-(2) to 24 (600 mm), as shown in Figure Page 2 of 11

3 Figure 15.36: Design values for links and pipes 16. Select the row for either one of the overland links. a. Change the channel type to Open Channel. b. Set the shape type to User-Defined, as shown in Figure Page 3 of 11

4 Figure 15.37: Gutter slope in cross-section; this will be the overland channel shape. c. Set the Cross Section ID to XS-L-Pipe-(1). d. Click the ellipsis next to XS-L-Pipe-(1) to open the Irregular Cross Sections dialog. The shape you see in Figure is an exaggerated view of a curb and gutter. In the previous example, you approximated the curb and gutter channel using a rectangular open channel. In this exercise, you will use one of the cross sections created for you by the export process. 17. Rename the Cross Section ID to C&G. Close the Irregular Cross Section dialog. 18. Make sure both Link-01 and Link-02 are using the C&G cross section for open channel flow by setting the Cross Section ID for each. 19. Click Close when your conveyance links are complete. 20. Double-click Project Options in the data tree. a. Set the Hydrology method to SCS TR-55. Page 4 of 11

5 b. Set the Time Of Concentration method to SCS TR-55. c. Set Minimum Allowable TOC to 6 minutes. At the end of this step, your Project Options dialog should look like Figure Figure 15.38: Project Options for this example (metric is shown for illustration purposes) 21. Click OK. 22. Back in plan view, double-click the west subbasin icon. 23. Switch to the SCS TR-55 TOC tab. You will enter the following information to compute TOC for the western subbasin: a. On the Sheet Flow subtab, set the Manning s roughness value for Subarea A to This value is based off the TR-55 listing for different land conditions. The listing of values can be found by selecting the ellipsis next to the entry field. b. Set Flow Length to 150 (45.7 m). c. Set Slope to 5%. This is another site-specific value and represents the average overall slope of the subbasin. d. Click the ellipsis next to the 2Yr-24Hr Rainfall, and in the resulting dialog, choose Pennsylvania from the State drop-down and York from the County drop-down, as shown in Figure (Metric users, enter a Page 5 of 11

6 value of 79 mm for rainfall value, because this specification is only reported in inches.) Figure 15.39: Sheet Flow input and rainfall location e. Click OK. Selecting the rainfall location at this point is helping you determine the Tc. Your actual design storm duration may vary. Later in this chapter you ll learn more about rainfall. 24. Switch to the Shallow Concentrated Flow subtab for Subarea A. a. Set Flow Length to 250 (76.2 m). b. Set Slope to 5%. c. Set the surface type to Short Grass Pasture. The velocity for sheet flow will calculate based off the nomograph, which you can examine by clicking the ellipsis button next to Velocity. Your results should resemble the top of Figure Figure 15.40: Shallow concentrated flow and channel flow for TR-55 [f1540.tif] 25. Switch to the Channel Flow subtab and set the Manning s roughness value for Subarea A to a. Set the flow length to 433 (131.9 m). Page 6 of 11

7 b. Set the channel slope to 3%. c. Set Cross Section Area to 14.5 ft 2 (1.35 m 2 ). d. Set Wetted Perimeter to 12.2 (3.7 m). Wetted Perimeter and Cross Section Area are site-specific values and are needed to calculate the hydraulic radius used in the Manning s roughness equation. Figure shows a schematic of what these values mean in channel flow. Figure 15.41: The Cross Section Area and Wetted Perimeter values are used to find the Tc for channel flow. After entering the values for channel flow, your dialog will now resemble the bottom of Figure Still working with Sub-Structure - (1), switch to the Curve Number tab. 27. Set the curve number values for the subbasin as shown in Figure Figure 15.42: Use these values on the Curve Number tab to create a weighted curve number (metric areas are shown for illustration). 28. Switch to the eastern subbasin by highlighting Sub-structure - (2) in the tabular listing near the bottom of the dialog. The Tc parameters for this subbasin are: Page 7 of 11

8 Make It Rain Sheet Flow: Manning s roughness of 0.17, Flow Length of 200 (61.0 m), and Slope of 4.5% Shallow Concentrated Flow: Flow Length of 412 (125.6 m), Slope of 4%, and Surface Type set to Short Grass Pasture Channel Flow: Manning s Roughness of 0.05, Flow Length of 305 (93.0 m), Channel Slope of 2%, Cross Section Area of 12.2 ft 2 (1.13 m 2 ), Wetted Perimeter of 8.4 (2.5 m). 29. Still working with Sub-Structure - (2), switch to the Curve Number tab and set the curve number to 45 for the entire area. 30. Click Close. Save the file as C3DtoSSA.spf. There are several methods for telling SSA the rainfall information for the model. A typical rainfall event in Herten, the Netherlands, is going to be vastly different from Arizona. In the previous exercise, you set up many of the physical characteristics of the hydrologic system. You did not, however, tell SSA what type of rain to expect on the site. Different hydrology methods require different assumptions about rainfall. In the Rational method, you used an intensity-based rainfall model (IDF Curve) because you were primarily interested in peak runoff. Because this is a TR-55 example, you will need to use rainfall information appropriate for this method. 1. Continue working in the file from the previous exercise or open SSA- Rain.spf (or SSA-Rain_METRIC.spf) in the Storm And Sanitary Analysis program. 2. From the top of the SSA screen, select Add Rain Gauge. 3. Click anywhere in plan view to place the rain gauge in the project. 4. Press Esc on your keyboard to return to Selection mode. 5. Double-click the New Rain gauge, and rename the Rain Gauge to Design Storm. a. Set Rain Data Format Type to Intensity. b. Set Incremental Interval to 0:20. Page 8 of 11

9 At this step your Rain Gauge dialog will look like Figure Figure 15.43: The Rain Gauge dialog 6. Click the ellipsis next to Time Series. 7. In the Time Series dialog, click Add. 8. Rename the Time Series to York, PA Set the data type to Standard Rainfall and click the Rainfall Designer button. a. Set Rainfall Type to Intensity. b. Set State to Pennsylvania and County to York. c. Set Return Period to 50 years. 10. Make sure that the Unit intensity check mark is set to SCS Type II 24-hour, as shown in Figure (Metric users, override the rainfall value by entering 157 mm.) Click OK. Figure 15.44: Rainfall Designer dialog Page 9 of 11

10 11. Once your Time Series dialog resembles Figure 15.45, click Close. Figure 15.45: The completed time series 12. In the Rain Gauge dialog, click Assign. a. Click Yes when asked if you d like to assign the rain gauge to all Page 10 of 11

11 subbasins. b. Close the Rain Gauge dialog. 13. Double-click Inlet Structure - (1). Expand the Inlet ID column to get a better view of the table. 14. Set Roadway Gutter Bypass Link to Link Switch to Structure - (2) by selecting it from the table at the bottom of the Inlets dialog. 16. Set Roadway Gutter Bypass Link to Link-02, and click Close. 17. Double-click Analysis Options on the data tree. 18. On the General tab, set the Analysis Duration to 1d by changing the date in the End Analysis On field to one day after the Start Analysis On (the exact date will vary depending on when you open the file). 19. On the Storm Selection tab, set Single Storm to Use Assigned Rain Gauge, and click OK. 20. Click Perform Analysis. 21. After the analysis runs successfully, click OK. Explore the results by double-clicking of the different project elements. Save and close the project Page 11 of 11