It has been quite ironic that while I have been writing this series of articles on building data for heavy highways, I have luckily been in the middle of building a number of different heavy highways throughout our Nation. Nowhere in my office will you find some form of a checklist or routine for building highways - or any project for that matter. I know what needs to be done and I just truck along until it is finished. You can therefore imagine the challenge in putting to paper a routine and procedure that you don't give any thought too while moving through it. After I decided to write this series of articles, I have been paying close attention to these current highways I have been working through. While this has not made writing these articles any easier, it has at least given me a chance to review my procedures and techniques - which trust me, are far from perfect. If anything else, it has shown me that these general steps I have been outlining get the job done quickly, efficiently and above all, accurately.

Which brings us to our next step of highway data building. By this point in the process we have tackled the paper plans, set up our horizontal alignments (HAL's), sorted out the necessary edges of pavement or other transitions, entered our vertical alignments (VAL's) and survived the super elevations. It is now time to deal with our typical sections and transitions. But before I continue, I need to put in my software disclaimer. I use a beefed up version of Terramodel for all my work, and have used it for about 15 years. You may be sitting in front of AutoCAD or Microstation or Carlson or something else. There may be an entirely different procedure for dealing with typical sections and transitions in your software of choice. However, regardless of how you do it in your software, it will need to be done in some form or another since the program isn't going to build it on its own without any input from you. Well, not yet at least.

Typical sections in the planset end up being a well worn page after I am done building the project. I am checking them while building my HAL's. I am checking them while building my VAL's or setting up my supers. I only really stop checking my work against them when the project is done. As with all other components of building a heavy highway, if they are done poorly or incorrectly, your work will not be accurate. They *must* be correct and accurate. But before you do anything with them, there is a critical decision that you must make: how much of the highway do you want to build off of the roadway section we are working with and how much do you want to build by hand? This is a judgment call that must be made on a project by project basis. Sometimes the engineer will design components that can not be recreated by a roadway section in your software, such as a pond, curb return or non-uniform grading. Many times you will have to build these components by hand and your typical sections will just need to pass over these. However, as a general rule of thumb, I always try to build as much of the projects detail as possible by typical sections.

As with any portion of your work, you want to keep things simple. So what critical components do you need from the typical sections? Obviously you will for sure need all grade breaks. Is there a grade break at the shoulder? Is there a grade break at the edge of pavement? Does the engineer change grades outside of the clearzone? Are all these changes consistent throughout the project or does that 3:1 fill slope change to a 2:1 when you get closer to the bridge? Did the engineer give you a maximum breakover slope between the travel lanes and shoulder for when the roadway is in a super? These questions, and many more, need to be asked for each roadway and its typical sections. Whenever there is a grade or slope change, you need the typical to reflect this. Outside of that, you will typically not need any further information. I mean do they really need a grade point at the edge of each travel lane? If they asked for it then why not accommodate them? But if they did not, lets not add thousands of travel lane points if they are not defining a grade break. So again, since we want our files to be clean and efficient, keep your typical sections at the minimum amount of necessary detail to accurately follow the engineers design.

Another major question for your typical sections is whether or not you are also building a subgrade model of the highway. If you are, that changes things a bit. For one, you will have to extend your finish grade typical section to at least the subgrade daylight, and preferably past it. Since the subgrade daylight will change as the highway goes into a super, you need to make sure that you have at least extended the finish grade slope beyond where it normally is. Also, many State's will have a subgrade slope hinge on the high side of a super to ensure proper drainage. If you are not careful, these can bite you in the butt as the engineer will many times only show this in a random detail hidden somewhere in the plans. To make it even more challenging, the engineer will typically not show a specific typical section for full super, so unless you find that hidden detail you will never know that it should be in there. Typically though, subgrade sections follow the roadway slope and simply extend at that slope to the subgrade daylight. Building a typical is therefore a one shape ordeal - very easy fare. On the other hand, I have seen subgrade sections so crazy that they had to be built by hand. Sometimes this is the case, but for every one time I have to build subgrade by hand, the nine hundred times I build it off of the typical sections with no problems.

With the typical sections squared away, your roadway template is now completed. By this point, it will be comprised of HAL's, VAL's, super elevation transitions, edge of pavement (or edge of anything needed) transitions, and now typical sections tying it all together. I can not stress enough how important it is to get each and everyone of these steps not only good, but perfect. Any error in one of these components will ripple through at least that cross section, and sometimes the entire project. However, when done correctly, building a complete roadway template in your software allows you to do in seconds what it took our forefathers weeks or months to do. Want to change the super transition for those 200 feet? No problem. Want to adjust the daylight slope for the entire roadway? Three clicks and your done. It is because of this power in your software that we are able to recreate in hours or days what it took an engineer months or years to design. But if we are not careful and complete in our work and double checking procedures, this short amount of time that you spend with each project can make or break your job/business. Which brings us to an old saying I came up while working as an engineer:

All engineers make mistakes. The good ones catch 'em.

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