Civil 3D Guide to Sustainable Designing

March 27th, 2011

 

One of the fastest growing markets for the civil engineering industry is sustainable design. There has been an increase in this market even during the recent economic downturn. Sustainable design is a practice that I feel very strongly about; in my mind, green is always better. It is better for the environment. It is better for the inhabitants of such developments and better for the developers and owners. It can also have a higher value than traditional designs.

There are many levels of sustainable design, from minor changes in how we develop or redevelop, to certified sustainability designs such as a Leadership in Environmental and Energy Design (LEED®) project that is certified by the U.S. Green Building Council and other programs as well. Some of these programs are regional, and a quick Internet search could reveal other options available to you or you can have your designs certified. Bear in mind, however, that your designs do not have to be certified to make them sustainable designs. It’s all in how we decide to design our projects, but the certifications certainly do help and make it easier to judge just how sustainable our designs are. We have also been designing some forms of sustainability our entire careers. A perfect example of this is a detention or retention pond and many other design practices that we might not even recognize as sustainable practices. Of course, some of these design practices are forced on us due to regulations that we must follow in order to get our designs approved. But they are sustainable practices nonetheless.

The software we use can play an important role in our designs, not only in the design itself, but in the evaluation of sites and the surrounding area. When working on a sustainable design we have to consider more than just our lot and surrounding lots. We have to look at a much bigger picture. We have to consider many factors other than cost and a client’s desire. In many traditional design situations, owners would buy a piece of property and then come to an engineer with their intent for this property.

This method does not work as well in a sustainable design process. The engineer has to get involved sooner in the development process if a sustainable design is the intent of the owner, especially if he or she would like the development to be certified. As I have stated, there is much more to developing sustainably than just the property we are developing. With that being said, any development can be a sustainable development, or at least more sustainable than traditional developments. Even small changes can have a large impact overall. One day in the near future we will no longer refer to sustainable designs as sustainable. They will simply be “designs” once more as this type of development becomes the norm. For the rest of this article I will refer to sustainable designs simply as “designs.”

Aerial imagery

One very useful tool in designing is the use of aerial imagery. Images can come from many sources and in many formats, so I cannot get too in-depth in this short article. Of all of the data we work with, imagery is by far the one item that will use up our computers resources and make for a very bad day. Therefore, we have to be careful about the data we use in our drawings. AutoCAD® Civil 3D® gives a somewhat better result when working with images obtained by way of the Feature Data Objects (FDO) data access technology. FDO can use coordinate systems to place our imagery in the correct location based off of the Earth’s surface, or translate from one coordinate system to another.  If you have never tried this option, I recommend that you test it out. You can also use Google Earth, which contains free data that we can pull into our drawings, and is not limited to only imagery. In many locations you can also pull in surface data. Keep in mind this is not survey-quality surface data, but it can be very useful in a preliminary stage of design and site evaluation.

With imagery in our drawings we can get a better idea of not only our site, but also the surrounding area. What kind of development is around our site? Are there any bodies of water or streams nearby? What type and amount of development is in the area; what type of vegetation is on our site; is there public transportation in proximity to our development? An aerial image can easily show you the types of roads that surround our site. Last, but not least, images give our designs a much clearer picture. People without engineering degrees can understand the design intent and the impact on the environment a little easier.

GIS data

Geospatial data can serve so many purposes in our design process, and the amount of data in some locations is growing at a rapid rate. You may have to look pretty hard to find the data you’re after, or you may find that a simple Internet search will result in an almost overwhelming amount of data available to you for free or for purchase. The ways in which we can use this data and the different types of data that may be available in your area are beyond what can be covered in this article, but I will point out a couple of the ways to use this GIS data. Again I lean toward using the FDO connection to get this data into your design drawings.

Proximity analysis is one method that you may use in your design. It could be proximity of infrastructure, intersections, and even public buildings and green spaces. You may have access to the types of soils in the area or flood plain information. Let’s look at flood zone data, and let’s say that this data is in the form of a shape file or .shp format. Using the FDO connection, we bring the data into our drawing and let the FDO do any coordinate translations for us. After we have this in our drawing, we will likely want to adjust our style for these objects, adjust how this data is visually shown on the screen and when we create our documentation. Whenever possible, the documentation will be in a digital format rather than plotted on paper. Remember we are creating a sustainable design, which should include digital printing.

The Map task pane is where you will have your data listed and where you will make the adjustments to the data’s style. Select your data in the task pane, right-click, and select edit style; or select style in the upper section of this pane. A pop-up window called the Style Editor will appear and this is where you will make your adjustments. Next you will likely need to create a new theme to show the different flood zones. This is located in the middle of the editor on the left side in another pop-up box. You will need to know where the data for the flood zones is stored. It will be listed as a property, which is the first option to change in this box. After you select the correct property it will generate a range based on how many ranges are available. Next you can assign a style or color range to apply the look you want. The same steps can be used for soil types and many other types of data as well.

Site grading

Another important factor to consider is the site grading. We want to reduce the overall site grading to an absolute minimum, and if possible, to not have a single truck bring in or remove soil from the site. This will also save our clients money as well. After all, what tends to be one of the most expensive site improvements? Site grading, of course!

Let’s pretend we already have a grading group created for our design. The next thing we are going to do is to check our cut and fill. We are going to do a simple elevation adjustment to balance our grading to get it as close as possible to a net zero value. On the ribbon’s Home tab > Create Design panel > Grading, select Grading Creation Tools. The Grading Creation toolbar will appear. Next select Grading Volume Tools. Take a moment to evaluate your current values and select the automatically raise and lower button on the far right. Presto! Like magic, Civil 3D has balanced this grading group for you. Evaluate the model to see if the result is acceptable.

Training

AutoCAD Civil 3D contains some powerful tools that we often overlook or don’t utilize. These Map tools are built into Civil 3D. It is very common to get so overwhelmed with just learning Civil 3D that we take very little time to learn the Map functions and tools. Even the plain or “vanilla” AutoCAD functions tend to get overlooked by many civil designers. One of the biggest reasons for this, other than simply being overwhelmed with the number of features, is lack of training. Even expert CAD designers and the trainers themselves still need on-going training. I readily admit that I need lots of training and welcome any that comes my way.

As for those who claim not to need training, well, they don’t know what they don’t know. Hence, they can’t recognize that they also need on-going training, just as every other CAD user does. I understand that often the reason we do not get the training we need or desire lies in management decisions over which we have little or no control. Believe me, I feel your frustrations! So explain to management that you need AutoCAD, Map, and Civil 3D training. After all, they bought the software already so why not use it to its fullest?

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