Tutorial 19

 

In this tutorial you will learn how to design a simple road when you ;

 

¨    Enter Design Vertical Grading

¨    Enter a Design Section template for a Rural Road

¨    Calculate the Volume of material in the Proposed road.

¨    Plot Design Profiles and Sections.

 

Your client from Tutorial 18 has been on the phone again, and this time she wants to know if you can provide a preliminary design of the road/firebreak into her proposed ‘country property’.

 

She claims that she needs to build a ‘road ‘ that is 4 metres wide to allow for delivery of building materials, and would like you to provide her with profile, sections and approximate volumes so she can get ‘in principle approval’ from the local authority, as well as some indicative prices from contractors to build the road.

 

As a preliminary stage, you decide that you will try and use the material on site to form the road base, and then bring in some select material to form a 50mm finished  ‘cap’.

 

If you open job ‘boundary’ again, you will see a screen similar to that at the bottom of Page 1, representing where we left off last time.

 

Select the Profile Icon, followed by the Section Icon, and then pull down the Window menu and select Tile Roadworks to see the screen shown below.

 

Now the more astute among you will see that the ‘alignment’ at the moment consists of a series of straight segments without any ‘curves’, and while it is not normal to build real roads in this form, it is acceptable at this preliminary stage of investigation for a ‘dirt road’ on a private property, particularly since you client thinks you should do this extra work for free.

 

So we will leave the horizontal alignment as it is and let the grader driver smooth out the bends to suit on site.

 

We will concentrate on producing some ‘design vertical grading’ and then generate some ‘design cross sections’ to produce preliminary earthworks quantities.

 

It is important that you understand that what is presented in this exercise is simply one method of using the various tools contained within your Ezicad ‘toolbox’ to achieve a particular result. You may choose to use the tools in a different order, or use different tools to fit with your particular style of working.

 

It is far beyond the scope of this Tutorial to attempt to teach you how to actually design roads or other structures, and you may change the numbers we suggest to suit yourself if you wish.

 

The vertical grading process consists of adding in a series of Vertical Intersection Points (VIP) and then placing a Vertical Curve (VC) at some or all of these points as required.

 

Adding Vertical Intersection Points

 

You need to make the Profile Window active by clicking somewhere within it.

 

Once it is active, ‘right click’ within the window and a ‘design menu’ will appear as seen below.

Choose “Add” from the menu.

 

This puts you in ‘Add VIP Mode’, and each time you ‘left click’ within the profile window a new VIP will be added in.

 

Position your cursor at the start of the profile, and ‘click in’ a VIP as close to the natural surface as you can.

 

You will see a ‘box’ appear denoting the location of the design point.

 

Now, as you move the cursor about the profile window you will see a number of values on the bottom right being updated.

 

You will see that there are values for Chainage, Height, and Grade shown, and you can use these to give you an indication of where to place the next VIP.

 

However, remember that this ‘Add’ tool is designed to allow you to quickly ‘eyeball’ a design grading into the computer and then come back and fine-tune it afterwards.

 

There are a variety of other options available on the Design Menu if you wish to place the VIP’s more precisely, such as ;

 

In keeping with the ‘preliminary’ nature of our task, we will proceed with the ‘eyeball’ design method, and place VIP’s somewhere in the vicinity of the following locations

Chainage       Height

72                    188    

220                 190    

400                 191

500                 189.7

 

The screen should appear similar to that shown.

 

If you wish, you may maximize your profile window while you are working with it, but for the preliminary nature of this design I have simply chosen to eyeball it at the reduced size – again, I am trying to show you where the tools are and how some of them work. It is then up to you how you choose to implement them.

 

Adding a Vertical Curve

 

Now the change of grade at the second VIP appears a little severe, even for a ‘dirt road’ so we should look at adding in a Vertical Curve (VC) at that location.

 

Again access your Design Menu by ‘right clicking’ and this time choose VC.

 

You will be prompted to ‘Select IP to change”. Position your cursor in the box denoting the VIP at chainage 72 or thereabouts, and select it, and you will see the following screen appear.

The figures in this screen are indicative of one idea of the lengths of VC applicable for particular design speeds and particular changes of grade, and are intended as a guide only.

 

Feel free to use whatever lengths your personal experience and local knowledge dictate.

 

Try a VC length of 40 in this case and your screen will appear as shown.

Next add in a 50 metre VC at VIP near chainage 400.

 

This completes our preliminary grading (yes it is very preliminary, but it will give us the general idea of the material we need to move, and we can easily come back and fine tune it later).

 

Adding a Design Template

 

The next step in the ‘design process’ is to define the design section template (or templates) you wish to use along the profile.

 

Make your section window active by ‘clicking in it’

 

Then right click in the section window to bring up the Section Design Menu as shown

 

Here we wish to use a Predefined template, so select that option and then choose a Rural Road

 

The following screen will appear.

 

As you can see, this is actually ‘half a road’ and in particular the right hand half, and that is what we refer to as a ‘template’ within Ezicad.

 

Once you define the dimensions of this template you can ‘mirror’ it about the centerline if you wish (and in a rural road you normally do)

 

Click the ‘left and right boxes’ to indicate you will use it on both sides of the road.

 

Enter a ‘Pave (Pavement) Width’ of 2 – used each side will get you a 4 metre wide road that your client desires.

 

Enter a ‘Pave Grade’ of –4%

 

We don’t need a shoulder (though you normally would if it was a real rural road), so leave that at 0.

 

Likewise leave the drain at zero for the moment, and fill in Cut and Fill Batters of 50 and 50.

 

Now click OK to finish and save.

 

Now click on the Next or Previous button in the Section window, and you will see your ‘Designed Road’ start to appear at each section as you go through.

 

Any material coloured ‘blue’ is fill material – i.e. material that needs to be brought to that location, while any material coloured yellow is cut material – i.e. material that will be removed from that location.

 

If you wish to see these more clearly you can maximize the section window at any time.

 

The next step is to obtain the ‘earthwork quantities’ that are likely to result from our design efforts.

 

Obtaining the ‘Design Volume’

 

Pull down the Road Menu, choose Volumes, followed by Design Volumes and soon the following data (or hopefully numbers of a similar magnitude if you have done your own thing) will appear in your designated word processor.

 

This shows that without taking topsoil stripping into account, you have a slight excess of Fill over Cut, and you need to move some 1400 cubic metres of material around to produce the required result.

 

Since you have no geotechnical information available at this stage, it is not feasible to predict bulking and compaction factors, and it may also be necessary to ‘strip’ the topsoil before you actually construct the road.

 

If you wish to determine the amount of material involved if you do strip off 100mm of topsoil before you commence, you can achieve that very easily.

 

If you select the “big Green V’ icon,   you will see the Volume Parameter screen appear. Tick the ‘Stripping’ box, and then enter an amount of 0.10 in the adjacent field.

 

If you now run the volumes again, you will see that you now have an excess of some 400 cubic metres of fill required.

 

Since it will be expensive to bring in fill, you might now consider a site inspection to determine whether stripping is necessary, or whether you might be able to compact the existing material well enough to provide a good enough base, bearing in mind the likely very low volume of traffic and loads that this ‘road’ will experience.

 

Plotting the Profile

If you refer back to Tutorials 13 and 14 you will see the broad basis of all Profile plotting.

 

The essential difference here is that you now have a Design Profile to plot as well as the Natural Profiles covered there.

 

If you select the Profile Plot Parameter Iconyou will get the first screen that allows you to define ranges to plot, scales etc and you should be familiar with those from earlier Tutorials.

 

Select the ‘Format’ button and you will see the following screen.

 

This allows you to specify what should appear where on a profile, and what, if any, labels you wish to use.

 

You will see that the program has assigned Chainage to ‘Box 1”, Ref to box 2 and DSN to box 3.

 

If for some reason you prefer to draw a profile with the Chainage in the top ‘box’ and then put the other values below that you can achieve that by simply changing what is each ‘box’.

 

The box numbers stay the same, starting at the bottom and counting upwards, but you have complete control over what lives in each particular ‘box’

 

Likewise you are in control of what label appears on each box.

 

If you cast you attention to the column at the right you will see it is titles ‘Label’.

 

Position your cursor in the ‘label’ field for Box 1 and type in Chainage.

 

Now move to box 2 and enter a label of ‘Existing Ground” and then put “Proposed Road’ in as a label for box 3.

 

If you wish to play with different fonts and sizes, feel free to click on the ‘blank button’ immediately to the right of the ‘Box Contains’ column. You will then have access to the normal Windows font routines.

 

Once this is done, make sure that the Profile Window is active, then Use File>Print Setup to select a suitable size sheet of paper.

 

Once that is done, use File > Print Preview to see what you might get.

 

The screen below is one example of what to expect.

 

 

Plotting the Sections

 

You should likewise refer to tutorials 13 and 14 for the basis of plotting sections.

 

If you select the Section Plot Parameter Icon then the ‘Format’ button you will see the following screen.

 

Which has defaulted to the ‘normal’ location of the various elements.

 

If you have a different concept of ‘normal’ feel free to change it around to suit.

 

Here is the first sheet of sections