Civil FE/PE Exam - Transportation - How to Find Chord Length on a Horizontal Curve

[@bigfish4818]

The relationship you used to find the angle is in the new version of the PE manual from NCEES

[@alec2182]

Totally unrelated, but I have a soil mechanics question for y'all. When solving shallow foundation bearing capacity questions using Terzaghis formula, specifically for a square footer. How do you know which of the shape factors to apply to the bearing capacity equation? The CERM really only ever applies S (cohesion) and S (unit weight). The factor for S (surcharge) is not used in CERM examples. Of course, when I do a practice exam, the surcharge factor is used though. Can you please clarify when to use the factors. Thanks!

[@2tiffunny]

If friction angle (phi) = 0, then surcharge = 1. If friction angle (phi) is greater than 0 then surcharge = 1 + (B footing/L footing) tan phi

[@heavypackbackpacker631]

This question has an error and it made me realize there is also an error in the PE Civil reverence handbook version 1.1: The error in the question: The R and Delta given does not result in a curve length L = 500', so you cannot come to a reasonable answer depending on which equations you use. The error in the handbook: There is an incorrect equation on page 273 for calculating l,1 (defined: length of curve from PC to point p subtended by central angle little_delta,1). The equation is l,1 = R(DELTA)(pi)(little_delta,1)/180, but there should be no (DELTA) in the numerator.

[@codysims7465]

Thanks for the comment! You are correct that the radius and internal angle will not result in a length of 500'. You may find an error in a question during the actual exam. The best thing to do is solve the question given the information provided and don't overthink it. As far as the error in the handbook goes, I'll send this up the chain. Thanks for pointing it out.

[@aakaprince]

@@codysims7465 I totally disagree with you Cody, if we will use the equation in the PE HB for l1 (Length of curve from PC to point p subtended by central angle (delta1) you will find angle 42 degree not 33.75 and the length of the cord will be 366.4 not 296.79. Sorry brother your answer cannot convince me.

[@vincentaroux]

I agree with this comment to use the l,1 equation in PE HB 1.1 corrected as described in other comments (remove the DELTA), resulting in 42 degrees and 366 ft.

[@vincentaroux]

move this video to the transpo playlist

[@vincentaroux]

thanks for moving!

[@mohammadjawadmashkur7878]

How you came up with 33.75?

[@fouzianoutash7218]

It should 42 degrees