5.0 Task B Guideway Horizontal Alignment Assessment is the ONLY PART REQUIRED for me too complete;
5.4 “Your Task” is the part I have been assigned, covering QI. – V. (1-5)
All reference information is provided in the brief and other pdf; questions are in the brief or as follows;
To make it more clear, here are the exact questions, I need answered.
Your client wishes you to assess the relationship between curvature along the guideway and
both posted speed limit and average speed between stations, all as shown in Figure 5-1.
Please respond to the following:
I. In Table A.1 your client has qualified each horizontal alignment element in terms of its
curvature, according to the following categories:
o straight at 𝐾𝐾ℎ𝑐𝑐 = 0 deg/m
o slightly curved at 0 < 𝐾𝐾ℎ𝑐𝑐 ≤ 0.10 deg/m
o gently curved at 0.10 < 𝐾𝐾ℎ𝑐𝑐 ≤ 0.15 deg/m
o moderately curved at 0.15 < 𝐾𝐾ℎ𝑐𝑐 ≤ 0.24 deg/m
o tightly curved at 0.24 < 𝐾𝐾ℎ𝑐𝑐 ≤ 0.45 deg/m
o sharply curved at 0.45 < 𝐾𝐾ℎ𝑐𝑐 ≤ 1.15 deg/m
o very sharply curved up to at 1.15 < 𝐾𝐾ℎ𝑐𝑐 ≤ 3.50 deg/m.
Based on the theory discussed above, for each of these categories calculate the
minimum curve radius, 𝑅𝑅ℎ𝑐𝑐 (m/rad) and the minimum speed, 𝑉𝑉 = 3.6 𝑣𝑣 (km/h). For each
category, with the aid of an actual example on the guideway, discuss your impression of
these limits.
II. Discuss whether there is any clear relationship between posted speed limit and
elements’ curvatures. If so, does the relationship appear to be similar in form to the
theory between centripetal acceleration, speed, curvature as discussed above? What
other factors could any variation in the relationship between posted speed limit and
elements’ curvature be attributed to?
III. Discuss whether there is any clear relationship between average station to station
speeds and elements’ curvatures. If so, does the relationship appear to be similar in
form to the theory between centripetal acceleration, speed, and curvature as discussed
above? What other factors could any variation in the relationship between station to
station speeds and elements’ curvature be attributed to?
IV. Identify four locations that have high curvatures. For each, use the information from
Table A.1 to calculate the limiting curve speed corresponding to centripetal acceleration,
𝑎𝑎𝑡𝑡𝑡𝑡,ℎ𝑐𝑐 = 1.18 m/s2
. For each, compare your limiting curve speed with the posted speed
limit, and with the station to station average speed, at that location. Do you notice any
consistent trends across the four locations?
V. Discuss the way the curvature profile changes along the guideway as chainage increases,
in the context of the following aspects identified in Table A.1: adjacent development and
facilities, infrastructure elements, junctions/ intersections, and stations/ layovers.
Identify four examples of features that have heavily influenced the curvature profile.
