2002年12月1日 · We are installing a 150mm diameter perforated pipe within the French drain. Perforations of 8mm diameter; 4 rows of holes all in same half section of pipe. Infill is +10 to –20mm stone although contractor will ask soon to put in 20-40mm stone above the drainage pipe - availabiity of materials.

2007年4月5日 · Normally I will determine the min. slope which will produce a velocity of 2.5 fps (min) when the pipe is flowing full and the hydraulic gradient is equal to the slope of the pipe. This is will help carry sediment through the pipe system. And when not possible to achieve this velocity try to at least avoid a drop in velocity in the pipe system.

2003年1月16日 · Pipe size shall not be smaller than drain pan outlet. Minimum size below grade and below ground floor shall be 2-1/2". Drain shall have a minimum slope of 1/8"/ft Verify pipe sizing and discharge requirements with local authorities and codes. Depth of trap must exceed by one pipe diameter the total static pressure of fan.

2011年3月22日 · Depending on your pipe slope and drain velocity, you might need to use an orifice at the discharge to limit / control the drain velocity. Then I would like to point out that the correct direction during the design phase is to size the drain to reach a certain acceptable draining time. you can not wait 3 days to drain 5 km of you pipeline.

2010年7月20日 · The drain we installed had 3" perforated corrugated pipe with filter fabric wrapped around only the pipe. The pipe was set in a bed of drain rock and covered, and I thought we sloped it at 1/8" per foot slope (which is the maximum slope I can get; literally a 12" drop over 94' total length).

2009年3月21日 · Consult a concrete pipe manufacturer. Furnish and install one (1) 18" x 12" saddle, complete as specified, each. Furnish and install one (1) tap into existing 18" RCP storm sewer, complete as specified. Differential settlement is possible with a mortar joint; settlement may result in the pipe being sheared or cracked at the connection.

2007年1月3日 · Yes, the storm drain is the main conveyance to the pond. My regulations don't say anything about starting hgl. If SWMM models both systems simultaneously, basin and storm drain, that would be the best progam to use. I guess we are not too sure as to what the best answer is. Thank you !

2011年3月17日 · The ACPA design manual (that is the "Concrete Pipe design Manual" You said you have already) by hand with the help of hundred tables and diagrams, let You find the effective load on the pipe according to the laying procedure (trench, embankment, etc) and with the bedding class You can find the D-load (that is the strength of the pipe found under T.E.B. test) …

2006年6月9日 · Invert of the pipes in and out is the elevation at the bottom of the inside pipe wall, not the bottom of the pipe. Invert of the structure (MH or inlet) is the bottom of the inside of the structure, not the excavation depth. Engineering is the practice of the art of science - Steve

2003年4月3日 · The box is precast with 4" sidewalls. Assume a 0.2' fall across the box with inverts grouted from one to the other. The pipe coming in has an invert of 100.00' (To keep calcs simple, we'll assume there is no pipe bell) The 24" RCP wall thickness is 2.6" or 0.22'.