Siêu cao trong Civil 3D - Superelevation Civil 3D

Cách 1:
Siêu cao trước hết sẽ được tính tự động trong file tiêu chuẩn thiết kế, dựa trên các thông số Bán kính cong, Chiều dài đường cong chuyển tiếp, Bảng siêu cao, Công thức tính siêu cao.
Lưu ý về công thức tính siêu cao: nên lập theo trình tự sau (ví dụ theo TCVN: đoạn siêu cao lấy trùng với đoạn chuyển tiếp và mở rộng):

• transitionformula formula="{t}/({e}+{c})*{e}" type="LCtoFS"
• transitionformula formula="{p}*{t}-{t}/({e}+{c})*{c}" type="LCtoBC"
• transitionformula formula="{t}/({e}+{c})*{c}" type="NCtoLC"
• transitionformula formula="{t}/({e}+{c})*{c}" type="LCtoRC"
• transitionformula formula="{t}*({s}-{c})/({e}+{c})" type="NStoNC"

Cách 2: 
Import từ file CSV, cấu trúc file như sau (link):

1. Curve number
2. Station
3. Critical station type
4. Curve length
5. Left Outside Shoulder
6. Left Outside Lane
7. Left Inside Lane
8. Left Inside Shoulder
9. Right Outside Shoulder
10. Right Outside Lane
11. Right Inside Lane
12. Right Inside Shoulder

 Ý tưởng: có thể dựa trên file csv, lập mô đun tính toán lại siêu cao cho đơn giản hơn





Superelevation Specification Variables

Use the following set of variables to calculate transition distances.

{e}	Độ dốc siêu cao. Phụ thuộc vào vận tốc và bán kính, tra theo bảng thiết kế. The full superelevation rate. This rate is determined from the superelevation rate table, based on the design speed and curve radius.
{t}	Đọc từ bảng chiều dài chuyển tiếp, dựa trên vận tốc và bán kính. The value that is read from the transition length tables, based on the design speed and the curve radius. This value may not be an actual length, but some other value, such as a transition rate from which the length can be calculated.
{c}	Độ dốc mặt đường thông thường. The unsuperelevated normal lane slope (positive). This value is defined by the user in the Superelevation Properties dialog box.
{s}	Độ dốc lề đường thông thường. The unsuperelevated normal shoulder slope (positive). This value is defined by the user in the Superelevation Properties dialog box.
{w}	Bề rộng từ điểm quay đến mép ngoài quay siêu cao. The nominal width from the pivot point to the outermost edge-of-traveled way. This value is defined by the user in the Superelevation Properties dialog box.
{l}	Chiều dài của đường cong chuyển tiếp. The length of the spiral, if a spiral is involved in the transition. This is the actual length of the spiral element in the curve group.
{p}	The fractional part of the transition length before the start of the curve or after the end of the curve.
{q}	The rate of increase of centripetal acceleration traveling along a curve at a constant speed.
{v}

The variables in the previous table are used to calculate the following distances:

NCtoLC	Normal Crown point to Level Crown point (runout)
LCtoFS	Level Crown point to Full Super point (runoff)
LCtoRC	Level Crown point to Reverse Crown point
LCtoBC	Level Crown point to Beginning of Curve
NCtoFS	Normal Crown point to Full Super point (used instead of LCtoFS on undivided planar roads) for example the length of the superelevation transition
NCtoBC	Normal Crown point to Beginning of Curve (used instead of LCtoBC on undivided planar roads)
NStoNC	Normal Shoulder point to Normal Crown point (used for the Breakover Removal Method of superelevated shoulders) Use this section to view examples of the XML formats you can use for various superelevation attainment methods. Standard Attainment Method Example The following example shows the XML format you can use to calculate transition stations for undivided, crowned roadways using the AASHTO standard methodology: This example defines an attainment method whose name is "AASHTO 2001 - Crowned Roadway" which uses the standard adverse crown removal method of attaining superelevation. This example includes a calculation for the transition distance needed for shoulder breakover removal (type="NStoNC"). Planar Transition Attainment Method Example This example shows an undivided planar road. The roadway is not crowned, and there is no adverse crown removal. The Planar attainment method requires two formulas: one for curves that oppose the direction of the normal cross slope and one for curves that continue in the direction of the normal cross-slope. The following illustration shows normalized slope superelevation, where the unsuperelevated road is tilted downward from left to right. Therefore the curve to the left requires a longer transition than the curve to the right: In the following example, the Continuing section defines the Normal Crown to Full Superelevation distance runoff length {t} (derived from the transition length tables), minus the runoff length times the normal roadway slope {c} divided by the full superelevation rate {e}. The second formula defines the distance from Normal Crown to the Beginning of Curve as a percentage of {t} based on the variable {p} minus {c} divided by {e}. The Opposing section defines the overall transition distance to be the runoff length {t}. The distance to the Beginning of Curve is a percentage of {t} based on the variable {p}, and the distance between the Normal Crown and Level Crown stations is {t} * {c} / {e}. Transitions Defined by Roadway Width and Transition Rate Not all organizations use tables that give transition length directly. The following table defines the full superelevation rate and the as a function of design speed and curve radius. In this situation, the value is used to derive the transition length based on the normal width of the roadway. The Transition Length tables define the value instead of the actual transition length. Radius (m) 90 km/h 100km/h 110km/h 120km/h E% E% E% E% n/a 7000 NC n/a NC n/a NC n/a NC n/a 5000 NC n/a NC n/a NC n/a 2.0 0.31 3000 2.0 0.39 2.0 0.34 2.0 0.32 2.0 0.31 2500 2.0 0.39 2.0 0.34 2.0 0.32 2.0 0.31 2000 2.0 0.39 2.0 0.34 2.0 0.32 2.3 0.32 1500 2.0 0.39 2.0 0.34 2.2 0.33 3.0 0.33 1400 2.0 0.39 2.0 0.34 2.4 0.33 3.2 0.34 1300 2.0 0.39 2.0 0.34 2.6 0.33 3.5 0.34 1200 2.0 0.39 2.2 0.35 2.8 0.34 3.8 0.35 1000 2.0 0.39 2.6 0.36 3.7 0.35 4.5 0.37 900 2.2 0.40 2.9 0.37 3.7 0.36 5.0 0.38 800 2.5 0.40 3.3 0.38 4.2 0.38 5.7 0.39 700 2.9 0.41 3.7 0.39 4.8 0.39 6.0 0.40 600 3.4 0.42 4.4 0.41 5.6 0.41 500 4.0 0.44 5.2 0.43 6.0 0.42 400 5.0 0.46 6.0 0.45 300 6.0 0.48 The following example shows attainment methods and formulas for two types of roadways based on the previous table. The variable {w} is the normal roadway width from pivot point to edge-of traveled-way, defined in the Superelevation wizard.