AutoCAD Site Planning
CE 191T – Site Plan Development Assignment 11 – 100 points
In this assignment you will prepare a grading plan for 5 acres, plus or minus an acre, using the provided site plan dwg file. The grading area that you will work in is the area within the magenta boundary. Once you understand the boundary limits you can turn that layer off so it is not in your way. You will provide:
• TFC and P points for all curb median islands • G points for all gutter elevations • FL points for all valley gutters • GR points for all storm drain grate inlets • TFC point for all curb face inlets
Open the template file provided and Save As: LASTNAME_I_11.DWG TO YOUR PROJECT FOLDER
Download the following documents:
1. CoF Development Code a. Article 20 – General Site Regulations b. Article 24 – Parking and Loading c. Article 31 – General Provisions
Read these documents and use the information in them along with the general instructions in this assignment to develop the grading plan for this portion of the parking lot up to the building
Rules of the road: Minimum slope on any asphalt concrete pavement in any plane is 1% (0.01 ft/ft)
Minimum slope in any direction on concrete sidewalk of slab is 1.5% (0.015 ft/ft)
Maximum crossfall (transverse to the direction of the path of travel) is 2% (0.02 ft/ft)
Maximum longitudinal slope shall be 4.5% along the path of travel unless the path of travel provides resting areas as required by the ADA, but in no case shall the maximum longitudinal slope exceed the maximum allowed by the ADA
Maximum longitudinal slope on ramps shall conform to the ADA standards
Minimum slope on concrete valley gutters is 0.2% (0.002 ft/ft)
Curb is dimensioned in accordance with the City of Fresno Standard Plan
Curb and gutter is dimensioned in accordance with the City of Fresno Standards Plans
The Finish Floor elevation of any building shall be six-inches above highest breakover point for that building
The lowest onsite inlet top of curb elevation (grate elevation plus 0.50 feet) shall not bel less than the lowest adjacent inlet top of curb connected to the public storm drainage system in the street
The grade differential between the project side of the property line and the neighboring side of the property line shall not exceed six-inches without a retaining wall. The maximum differential shall not exceed 12-inches with a retaining wall.
Start at a known elevation and work towards the unknown. This usually means that you start with the street elevations and work onto your site.
Civil 3D Commands: L – Line Command
PL – Polyline Command
Create Feature Line
Point Creation Tools
Layers: C-SITE-CONC GREEN CONTINUOUS
C-SITE-TEXT-ELEV CYAN CONTINUOUS
C-STRM-PIPE BLUE CONTINUOUS
C-STRM-INLET BLUE CONTINUOUS
Grading Design: Note that the area for which you will create a grading design is the area in the magenta boundary. Once you know where the boundary layer is, turn off the boundary layer, C-SITE-GRADING_DESIGN_BNDY, proceed with the grading design using the rules above.
You will design TFC and P elevation for parking median islands, TFC and G elevations for curb and gutter, FL elevations for all valley gutters that you may include in your design, and GR elevations for all storm drain inlets that you may include in your design. Note the specifications for the point descriptors that you will use for each point to designate the design elevation. In other words, you will use AECC point objects to label the design elevation and to perform your design.
The boundary elevations for the grading design area have been designate in the drawing. You job is to design the TFC, P, G, GR, and FL elevations within this area.
On the following page is an illustration of the grading area with the boundary. The four corner boundary elevations are also shown.
You design and label the median island TFC and P elevation for a standard curb
You will use the following standard details for the dimensions of curb:
Remember these dimensions and refer back to these details for calculating TFC and Valley Gutter elevationss
In this Assignment you will annotate the TOP FACE OF CURB (TFC) AND PAVEMENT (P) for each island as shown below:
To design grading, start from the known and then work towards the unknown. In this case, the knowns are the boundary elevations provided in the template drawing. The remaining grading design will be completed based on these boundary elevations.
The best scheme is to design the P elevations and then add the TFC later because the TFC follows the pavement elevation by +.05 feet in design. The other tip is use the L (lip) elevation and not the TFC or G elevation in CURB AND GUTTER situations because the lip elevation sets the pavement elevation. The difference between the TFC elevation and the L elevation is -0.37 feet, i.e. the L elevation is 0.37 feet lower than the TFC elevation.fd
There are many ways to begin the grading design. We are going to start at the northwest corner of the boundary area and draw a Feature Line along the lip of the gutter to the northeast corner
Set the current layer to C-SITE-TEXT-ELEV
Start the Feature Line command and create a feature line using Create Feature Line
Use the NODE Osnap and click on the point that is set for the Lip of the Curb and Gutter at the northwest corner. This should be the 292.20 L point.
When you click on the node, you will see a dialogue that shows the elevation of the node point, 292.20.
Then you will be prompted to draw the feature line. Select A for arc as the first segment of the feature line will be along the arc of the lip of the curb and gutter. You will then be prompted to select S for the second point on the curb, type S and then use the NEAR Osnap to select a second point in the lip within the arc. Then use the END Osnap to select the end of the arc of the Lip. At this point, Select T for Transition as we are not done drawing the feature line. Next select L to draw a straight line segment from the end of the arc to the end of the lip at the northeast corner of the grading area. Now set the NODE Osnap and select the node of the Lip point set at the northeast corner. This point should be 291.70 L. You will be prompted with the elevation of the node point, 291.70. Select E for elevation at this point and the routine will accept the 291.70 elevation. Then use the ENTER key a couple of times to end the command.
You have drawn a feature line that is 3D.
Now go back to the first island at the northwest corner of the grading area and draw a line from the end of the curb return to the face of the curb and gutter as shown.
Fill in the dialogue box as shown make sure to click on Use current
Click OK when you are finished
You will be prompted to select a starting point for the Feature Line
Draw this line from the face of the curb and gutter to the end of the
curb return at the island
The Civil 3D commands don’t have a routine for extracting a point from a 3D feature and labeling it so we will use the ID command to list the elevation of the Feature Line at the point where the line crosses the lip and then use the Points, Manual command to set the point and label the elevation. You may need to turn off the C-SITE-CONC layer to do this as sometimes Civil 3D will default to the entity with the 0 elevation rather than pick up the 3D entity.
Type ID to start the Identify command and use the NEAR Osnap and select a point on the Feature Line that is as close to the construction line as you can get.
Now use the Point Manual Command to set a point at the intersection of the Feature Line and the construction line.
And click on the Points Create Tools and you will see this menu appear on your screen
Select the far left option and the Manual point command
Here is the point on the Feature Line that is near the construction line that we drew from the curb return to the face of th Use the
Slope/Grade-Distance Point command to set the P elevation at
the curb return for the island
When you are as close you can get, click and Civil 3D will report back th X Y Z ( l ti ) f th i t
Select the Manual point and set a point at the intersection using the APPARENT INTERSECTION Osnap. When prompted for the Description, use L for lip, and then accept the Elevation that is shown. It should be 292.13. Use the ENTER key a couple of times to end the command.
Now use the SLOPE-GRADE-DISTANCE routine to create the point elevation for the Pavement at the curb return of the island.
Select the routine and follow the prompts as follows:
Use the NODE Osnap to select the point that you just created at the Lip of the gutter. This sets the starting location and elevation of the calculation of the P elevation for the pavement at the curb return.
Select the end of the construction line at the curb return to set the direction of the calculation.
Then type the letter G to set the calculation to Grade and not Slope.
dEnter the cross fall of the pavement in percent, with no sign for up and minus (-) for down. We want the runoff to drain to the curb and gutter so we will not use a sign and use 2 for 2% upslope to calculate the P elevation at the curb return.
Select the end of the construction line at the curb return again to set the location of the P elevation point.
Accept 0 for the number of Intermediate points by using the ENTER key.
Select 0 for the offset by using the ENTER key.
Use the ENTER key to accept the Y promot to set a point at the end point of the construction line at the curb return.
Enter P for the pavement elevation at the Description Prompt
And the Point will appear at the end of the curb return with the P description and 293.01 Elevation.
You will have to use the ESCAPE key to end the command.
Set all of the north facing P elevations at the curb return elevations using this routine.
Add 0.50 feet to the P elevations to calculate the TFC elevations and add that point at each curb return using the Point Manual routine.
Also use this routine to set these procedures to set the P and TFC elevations the north/south curb line that runs parallel with the north/south curb and gutter along the east side of the grading area.
The ground has a drop or slope from north to south so we will grade the parking lot that way as well and try to push the runoff as far as the proposed storm drain located along the drive in front of the office commercial stores.
You would do this using valley gutters that slope from north to south and then using cross fall across the parking stalls to drain the pavement to the valley gutters.
Another method is the use only the pavement slope and drain to inlets that are connected by a pipeline system.
Either way you do the design, you must design using the minimum gradients for pavement and curb and gutter, and make sure that the building is safe from major events that could flood the site. You want the runoff to leave the site before it enters a building. You must also make sure that the ADA parking stalls do not exceed 2% cross fall or slope and that the ADA path of travel meets ADA standards for cross fall maximum of 2% and longitudinal slope of 5%.
If you choose to use valley gutter, you need to pick which drive aisle they will be in and then draw them into the aisles on the C-SITE-CONC layer. Use the valley gutter detail to draw them in and to calculate the P and FL elevations. Valley gutters are usually placed in the middle of the drive aisle and can be either in every aisle or in every other aisle. If they are in very aisle, then the grade break for pavement slope is along the parking stop lines. If they are in every other aisle, the grade break is usually in the middle of the aisle between the valley gutters.
Use the Slope/Grade-Distance Point command to set the P elevation at the curb return for the island
The following illustration show the process of setting the FL for the valley gutter
Once you have this end of the grading done, then move south to the building end of the grading area. This will establish the two ends of the grading area and allow you to work out the middle of the grading. Fixing the two ends reduces the number of possible solutions to the problem and saves you time.
The building must be flat, or in other words, the walk and curb in front of the building cannot have a longitudinal slope. There will be cross fall across the sidewalk away from the building towards the parking lot, but there will be no slope parallel with the building. You can see that in the two TFC elevations set at both ends of the grading area. They are both the same elevation.
This means that any longitudinal slope on the parking lot parallel with the building must be created by the cross fall on the pavement from the building to the storm drain line and valley gutter.
Start by drawing the valley gutter parallel with the building and centered on the storm drain pipeline. The valley gutter should terminate at the center of the most easterly aisle.
The allowable cross falls from the curb at the building to the valley gutter will range from 1% at the upstream end of the valley gutter to 2% at the downstream end of the valley gutter.
Draw the construction line.
Use the ID commend and the Manual Point Command to set the
Lip of the curb and gutter.
Use the Slope/Grade-Distance Point command to set the P
elevation at the curb return for the island
Use the Slope/Grade-Distance Pint command to set the P elevation at
the valley gutter for the island (I used -1.5% from the P elevation for
the curb return to the P for the valley gutter because we are
working from the low side elevation and I wanted to reduce the bump into the valley gutter from the pavement as you turn
into the aisle.
Low Side P
High Side P
Since the parking lot drive aisle in front of the building is 27.8-feet wide, half of which is 13.9-feet. The valley gutter is 4-feet wide as illustrated in Detail A/30, half of which is 2-feet. The distance from the TFC to the edge of the valley gutter is 13.9-2 = 11.9-feet.
The range of deltas from the pavement at the building TFC to the valley gutter are:
0.01 x 11.9 = 0.12 feet feet 0.02 x 11.9 = 0.24-feet
Using a minimum longitudinal slope on a valley gutter of 0.002 ft/ft means that the maximum run on a valley gutter to stay within the limits of 1% to 2% cross fall is:
Run = (0.24-0.12)/0.002 = 60 feet. This does not work so we need to push the storm drain and the valley gutter to face of the endcap islands. This gives us double the distance of fall and double the run between grade breaks in the valley gutter.
New cross fall run = 27.8 – 2 = 25.8-feet
0.01 x 25.8 = 0.26-feet 0.02 x 25.8 = 0.52-feet
The new run between grade breaks is (0.52 – 0.26)/0.002 = 130-feet
Draw the valley gutter that runs parallel with the building as shown below:
Then move the storm drain over as shown.
Center the 4’ wide valley gutter on the TFC of the median cap. This will probably preclude planting trees in the endcaps so we may need to redistribute the tree wells in the parking lot.
Move the inlet so that it center in the valley gutter elbow and then use it as a junction box to turn the storm drain from the Type D inlet.
Now place a P point at the extension of the valley gutter centerline to the building curb face using the Manual Point command and a P elevation for the valley gutter using the Slope/Grade-Distance command. Use -2% for the grade. You want -2% because this is the downstream end of the valley gutter with the inlet and minus because you want the pavement to slope from the building to the valley gutter. Enter the 2% as 2 not as 0.02.
Draw circle with 130-foot radii to mark out the grade break locations as illustrated in the picture
It looks like you can just stretch to the center of the third aisle west to make our grade break.
Zoom down on that aisle and draw a construction line using the MID Osnap on the northerly line of the valley gutter to the south side of the valley gutter. Now use the Slope/Grade-Distance point command to set the P elevation at the proposed grade break location. Use the NODE Osnap in the command to select the easterly P elevation at the valley gutter. Then follow the prompts. Select G for grade and enter 0.2 for the slope to indicate a positive or up slope of 0.002 ft/ft. Use ESC to end the command.
You should get a P elevation at this point of:
Now use the Manual Point command to set a P elevation at the building curb. Use the cross hairs to line up the point location along the curb with the P elevation at the valley gutter that you just created. This is not really necessary, but it helps focus what you are doing next.
Now check the cross fall from the P elevation at the building curb to the P elevation at the valley gutter.
Cross Fall = (Pcurb – Pvg)/Run x 100 to calcualte the cross fall in percent
Pcurb is the pavement elevation at the building curb
Pvg is the pavement elevation at the valley gutter Run is the distance from the building curb face to the south edge of the valley gutter
Cross Fall = (290.42-290.16)/25.9 = 1.0% This meets the minimum elevation criteria so OK.
Now create the next low point in the valley gutter using the Slope/Grade-Distance command. Find the next grade break location using the circle to the west and draw a construction line using the MID Osnap from the north side of the valley gutter to the south side as you did before but use the -0.2 grade to slope down to a new inlet that will be located at this point. It should look like this:
Now you can start to work out the endcap island P and TFC elevations using the valley gutter elevations. You can use the Slope/Grade-Distance point command to set the P elevation opposite each of the curb returns along the valley gutter. The nice thing about the command is that the starting point and elevation stay locked in, but you will have to specify the direction and distance for each subsequent point along the valley gutter.
Start the command, select the starting node using the NODE Osnap, select the end point of the construction line at the high point aisle, select G and enter 0.2, then use the NEAR Osnap and your cross hairs to line up the next point opposite the curb return, accept the next prompts and enter P when prompted for the point description. Now select the end point of the construction line again when you see:
Specify a point to define the direction of the intermediate points:
Enter 0.2 at the Grade prompt (Civil 3D will hold the Grade setting). Usie the NEAR Osnap and the cross hairs to locate the next point opposite of the next curb return. You should end up with elevations like this:
Now you have to decide if you want a 0.5-foot curb face where the valley gutter flow line (invert) meets the curb or if you want a 0.625-foot curb face because the valley gutter has a 1.5-inch drop from the edge to the flow line. In this demonstration we will accept a 0.625-foot curb face (7.5-inch), but will require that a detail be prepared to show the contactor how to construct this.
Using this, the TFC elevation will be 0.5-feet higher than the P elevations. You can use the Manual Point Command to set the TFC elevation on the south side of the endcap.
The north side of the endcap TFC should be high enough to slope from the curb return to the valley gutter.
Now you can work out the interior grades to the grading area. You are probably now going to have to use a valley gutter in each aisle. You can saw-tooth the north-south valley gutter or keep them all sloping south. The least expensive thing to do is to slope all south, but you might get caught where you need to saw-tooth the valley gutter in order to keep the cross falls within the range of 1% to 2%. You can stretch to 2.5% or 3% maximum. Do not exceed 3% in Fresno as people are not used to slope over 3% in the Fresno area.
Also remember that the maximum cross fall in ADA travel way is 2%. So all ADA parking stalls need to have pavement slopes that do not exceed 2%. Most designers use a maximum of 1.75% to avoid having to tear out pavement due to construction tollerances.
It is also better to keep cross fall on median islands to a maximum of 3% to avoid irrigation water overflow on the low side.
Before you move on, check the longitudinal slope on the valley gutter in the most easterly aisle. Use the P elevation at the north end and the south end and distance between the two to calculate the slope. It should look line this:
(292.41 – 289.90)/275 = 0.0091 ft/ft this is greater than 0.002 so OK.
- CE 191T – Site Plan Development Assignment 11 – 100 points