calculating delta angle

[mhodges80]

I have a question for anyone out there who can help me. I am a chemical/mechanical/nuclear engineer working w/ traffic engineering currently. I just want to know what is the "delta angle" and how do i calculate it? Our site plans call for radius, chord, length and then delta (which i looked online to find was called the delta angle). I do not know what it is used for or how it is calculated and was hoping someone could help me or steer me towards a textbook that would explain it. Thanks.

 

[francesca]

Ask the person who will be stamping the plans. They should know and if they don't, they should have a PE Reference Manual or a traffic engineering text book. It is a simple concept and if the person stamping the plans doesn't know then it might be worth a call to the Board.

 

[ACtrafficengr]

If you are talking about the delta angle for a highway curb, any highway engineering textbook should suffice.

Since you are working out of your discipline, any civil type that doesn't respect you more for asking is a poopoohead!

"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail." - Wm. Phelps Eno, ca. 1928

"I'm searching for the questions, so my answers will make sense." - Stephen Brust

 

[exCLP]

Delta angles...This is one of the ways for laying out a horizontal circular curve: Deflection Angle Chord Method. Delta Angle is the central angle, measured from the center of the curve, from the Beginning of Curve (PC or BHC) to the point on the curve. A good source to learn more would be a Survey textbook, the chapter on Horizontal Curves.

Sorry about the rudeness of some of the other posts. Some people have not experienced the financial need to switch between fields. When the economy in their dscipline goes down, like aerospace and oil & gas occasionally do, they will get their chance to learn.

 

[francesca]

Actually I have found the need to switch fields; from traffic modeling to subdivision design. When I didn't know how to do something I asked my supervisor. I suggested asking the person stamping the plans because a real live human is a much better teacher than the internet. I'm sorry that you find it rude.

I find it intriguing that you think it's okay for a person "working outside of their discipline" who doesn't know how to do a simple concept to wing it off the internet and stamp plans. (I'm not suggesting the OP is doing so.) I personally wouldn't want to enter a building designed by someone who didn't know how to do a bending moment diagram. Nor would I want to drive on a road designed by someone who cannot find out how to calculate a delta angle. I can only imagine what the curves were like seeing as the delta angle is in the same book as the sight distance and superelevation equations.

 

[peter111]

Hell, there are plenty of badly designed roads out there with plenty happily driving on them.

Actually I am a very experienced Traffic Engineer and to my shame I have never used a delta angle not being a Highway Engineer. We do like to specialise in our professions!!!!

However I can design you a very nice junction which will look great and handle traffic well. What I do is combine one circle with the right radius for turning with a couple of bigger ones and some straight lines. Not the correct way but it works and looks good. Hopefully the builders follow my plans.

 

[mhodges80]

thanks everyone for the help. i didn't mean to have anyone get upset by the other posts. I feel the need to clarify as it seems some are afraid I am merely trying to use the internet to solve a problem that may potentially be in use for the public. While currently getting my PhD in mechanical/nuclear engineering I am currently employed to design underground conduit. My coworker asked what a delta angle was in regards to our land easement. I, not knowing (considering my background is chemical separation and reactor design) anything about the geometry he was asking, decided to post on here and let the experts help me out. Rest assured there is no PE stamp going on any print that I am putting out; I was merely helping out someone who had a cad file that didn't match up to his calculations and wanted to know just what a delta angle was used for (he is not a civil engineer). thanks again everyone for the help.