Thank you! I haven't dealt much with spiral curves in over 30 years and your video helps.

@FindleyDaniel

2 ай бұрын

You're welcome, I'm glad this was helpful for you!

Great video. My 20 year-old notes from college weren't making sense. You helped bring it all back. Thank you.

Thank you!

@FindleyDaniel

4 ай бұрын

You're welcome!

Great mini-lecture and explanation!

Thanks for the video it was very helpful! I know you touched on how points could be located along a spiral by deflection, just like a horizontal curve but do you mind explaining the values that theta S/3 is multiplied by? It looks like a cursive L over another L squared?

@FindleyDaniel

4 жыл бұрын

The lowercase L is the arc length to any point along the curve and the uppercase L is the full spiral length.

Would it be important as a surveyor when locating a road or railroad tracks to locate not only an accurate as possible pc and pt begin and end but the pcc as best that they can actually visually tell in the field or has technology surpassed having to use these types of more old school methods in the field and the office side can calculate more efficiently now than is needed? I have been surveying for about 17 years and I started implementing an experiment so to speak where I indicated what I believe to be points of compound curvatures etc when I did a couple of projects that would have sidewalks designed crossing over railroad and highway right of ways. My forethought was that yes we have some pins marking the right of way east and west along the right of way but for safety sake I would want to see a tight check of the offset off of the edge of tracks, road etc to the row. I haven’t had a chance to work in the office before and never get a lot of good answers from them most of the time because they’re pretty busy but I was wondering if I’m just overthinking this or if I am on to something.

@FindleyDaniel

2 жыл бұрын

Johnny, great question! I'm not a surveyor, so I don't have the practical experience to give you a definitive answer, but the technology is capable of providing many additional incremental points, so I would suspect that more points are used.

when do we used spiral curve in road design?

@FindleyDaniel

4 жыл бұрын

Great question! Spirals are recommended according to the Green Book in Table 3-18. Beyond these values, the spiral transition doesn't add much value. This is based on p (the lateral offset) - if it is less than 2/3rds of a foot, the value will be minimal because drivers will introduce a spiral transition on their own anyway. From Table 3-18, as an example, at a design speed of 60 MPH, the maximum radius for the use of a spiral curve transition is 1,822 feet. So, for this example, if the curve has a radius larger than 1,822 feet, you don't need to use a spiral transition.

@FindleyDaniel

4 жыл бұрын

Mark, I've put together a new video on this topic, hope it helps you: kzread.info/dash/bejne/anp5yJOpe7eec9Y.html

If Ls in not equal to Ls out. What the formular to calculate Ts

@FindleyDaniel

4 жыл бұрын

Great question! I'll check around to see if I can find equations for an asymmetric spiraled curve. They're not as common, but they are needed in some locations. Let me know if you find anything too. Thanks.

@FindleyDaniel

4 жыл бұрын

Here is the content from Hickerson that may be useful: drive.google.com/file/d/1YpD9pLtNpkgOR5U71ml9M81eUG9NmmiC/view?usp=sharing

@FindleyDaniel

4 жыл бұрын

This is the document - www.amazon.com/Route-Location-Design-Thomas-Hickerson/dp/0070286809

hello can you derive some formulas of the spiral curves? thank you

@jajataposlukas3030

6 жыл бұрын

it is best to just memorize it, deriving the formulas from spiral is not recommended for me

Hi where is the Dc in the drawing?

@FindleyDaniel

5 жыл бұрын

Great question, the Dc represents the amount of curvature and is a function of the radius, so it isn't a directly displayed parameter of the curve, but is related to the curvature through a relationship with the radius. The equation is Dc = 18,000 / ( Pi x Radius )

@nellvincervantes3223

5 жыл бұрын

@@FindleyDaniel thanks you!

Hey can i ask you question please? I need help with that (it's down there)

@slimlady5817

4 жыл бұрын

If we have : the R , Front and back hooks, and O...but we can't get to PI and we can't use (Pc & PT) as a Fulcrum to drop curve stations...and also we can't get to O when you only have a device that measures angles and distances? And really thanks

@FindleyDaniel

4 жыл бұрын

Hello! If I understand your question correctly, I believe this information will help you: drive.google.com/file/d/1cAMyfVQw2WHE9c2VmI9uvLn2zUEv15Ip/view?usp=sharing

@slimlady5817

4 жыл бұрын

@@FindleyDaniel Oh sorry for my bad english...for simple curves I meant ( we can't reach the 4 points(P.I,PT,PC,O)) but we have R and both Tangent extension

@FindleyDaniel

4 жыл бұрын

@@slimlady5817 No worries! Here is the link for similar equations for a simple curve: drive.google.com/file/d/17wmtL1APeUvFUs5JmJjbRP_ZlKZ1Onc0/view?usp=sharing

@slimlady5817

4 жыл бұрын

@@FindleyDaniel thanks Daniel

Hi I have a question for the PI that have different length of spirals, cause when I calculate this with normal formula it doesn't match with the one that I created with AutoCAD

@FindleyDaniel

11 ай бұрын

That's correct, these equations are only for symmetric curves (with both spiral transitions equal).

@derihilyas

11 ай бұрын

Do you perhaps have an equation for my case?

@FindleyDaniel

11 ай бұрын

@@derihilyas Unfortunately, I don't think I've made a video on this topic yet - but it's on my list to complete.

@derihilyas

11 ай бұрын

@@FindleyDaniel, Really appreciate your response, man. Also can't wait for the content to be released. But for now, do you have a link for kinds of literature/references about it?

@FindleyDaniel

11 ай бұрын

@@derihilyas I think the textbook by Hickerson should have these detailed equations.