I'm in search of a method/software to design a low vehicle clearance vertical curve. The access road to my site crosses a levee and I need to bring in equipment on a 40' lowboy trailer with 8" clearance. I've searched AASHTO, AREMA, ITE, DOTs, and various manufacturers to no avail.
Let me know if you find anything.
I searched long for anything on vertical curves and trucks. We had a site with a steep driveway and we needed a way to find out if trucks would bottom out on the curve.
The only thing I ever found was cross slopes on shoulders for tipping.
Check AutoTurn Pro from Transoft Solutions for this.
From the brochure:
Generate 3D swept path envelopes with vehicle height and ground clearances
to analyze designs in a three-dimensional space. Users also have the options to
display the 3D swept path of the vehicle body or body clearance.
I think the Institute for Transportation Engineers (ITE) may help you. They have several publications pertaining to design for low clearance vehicles.
Thanks for the brochure. I requested their demo version and will post my results.
At a minimum with a design like this I would want a profile at the top of the vehicle so I could see the clearance in profile view.
If I had a corridor I would add a vertical link and marked point to the CL extending up to the top of vehicle. I would hide the vertical link in the subassembly code.
If I did not have a corridor I would copy the FG profile and move it up to the top of vehicle.
Thanks, John, but in this case I'm only interested in that the trailer undercarriage clears the top of the levee.
I've performed a fairly exhaustive search at the state, federal, and local levels for applicable guidelines but no luck so far. I also contacted a half dozen or so manufacturers thinking there might be industry guidelines but zero there too.
The literature on AutoTURN Pro software is promising but the program doesn't include lowboy trailers. The Wisconsin DOT provides a lowboy trailer in AutoTURN format BUT THE DEMO VERSION WON'T IMPORT VEHICLES. Sorry, I was yelling and throwing things.
I actually calculated the clearance but my formula only accounts for two axles and the clearance - not the impact of the gooseneck pivot or the other three axles.
So... at the moment all I have for certain is a drawing of a tractor and lowboy trailer that looks really cool when I rotate it around my vertical curve.
Maybe AutoTrack can help where Autoturn did not.
I would still run a second profile but for the undercarriage to help identify problem areas as this is a quick estimation but it sounds like you will still need to manually draft the vehicle undercarriage line in the worse case position and manually place that along a profile. I would see if I could get a profile label to place a block of the undercarriage all along the profile. It will look ugly but you should be able to clearly see issues.
I would guess you have measurements on the tractor/trailer and or manufacturer's data to get the undercarriage line drafted.
We've use Autopath by CGS for this.
It's great for looking at both horizontal swept paths and vertical curve / vertical grade break analysis. It comes with a selection of vehicles.
However, you can also add your own customised ones (for both horizontal and vertical anlysis). (We've loaded our own truck towing a boat on a boat trailer for analysing boat ramp design - the custom vehicles look awesome).
When you run the software you can select a profile and it'll sit your vehicle on the profile and then run it along along the profile (use a 1:1 vertical exagerration in your profile view style). You can freeze the vehicle at any point and leave an outline on the profile if you want.
Have a look at the website here:
Looks like there's a free trial available.
Thanks, Michael. (I think.) Now I've got three programs to evaluate - AutoTURN, AutoTRACK, and AutoPATH!
John, I have a truck/trailer drawing to visually check for clearances but it only accounts for two axles and the bottom clearance. I'm not sure how to model the gooseneck pivot and the other 3-5 axles or even if it's necessary. I may be way overthinking this but it's going to be tough to explain if I send a truck to the river and it gets stuck on the levee road I designed. Oh, well. I've been thrown out of better bars than this.
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