1$Simple\ Curve$
Deflection and Central Angle of a
Certain Point along the Curve
$\alpha\ =\ \frac{\theta}{2}$

2$Simple\ Curve$
Perpendicular Offset from
the tangent of the Curve
$\ tan\ \alpha\ =\ \frac{x}{b}$

3$Simple\ Curve$
$\left(Radius\ of\ Curve\right)$
$(R)$
$20\ m\ =\ \frac{\pi\ R\ D}{180°}$
$100\ ft\ =\ \frac{\pi\ R\ D}{180°}$

4$Simple\ Curve$
$\left(Curve\ Length\right)$
$(L_c)$
$L_c=\frac{\pi\ R\ I}{180}\ \ \ =\frac{20\ I}{D}$

5$Simple\ Curve$
$\left(Tangent\ Distance\right)$
$(T)$
$Distance\ of\ PI\ \Longleftrightarrow PC$
$Distance\ of\ PI\ \Longleftrightarrow PT$

6$Simple\ Curve$
$\left(Length\ of\ Long\ Chord\right)$
$(L)$
7$Simple\ Curve$
$\left(External\ Distance\right)$
$(E)$
8$Simple\ Curve$
$\left(Middle\ Ordinate\right)$
$(M)$
9$Minimum\ Radius$
$(R_{min})$
$R_{min\ }=\ \frac{v^2}{g\ \left(e+\mu\right)}$

10$kph\ \Rightarrow\ \ \ \ m/s$
$kph\ \ \ \ \ \Rightarrow\ \ \ \ \frac{kph}{3.6}\ \ \ \ \ \Rightarrow\ m/s$
11$Impact\ Factor$
$(I.F.)$
$I.F.\ =\ e+\ \mu\ =\ \frac{v^2}{g\ R}$

13CONCEPT
DETERMINING STATIONS in all
HORIZONTAL CURVES
14$Compound\ Curve$
Common Tangent
$(CT)$
$CT=\ T_1+T_2$

15$Reverse\ Curve$
Common Tangent
$(CT)
$
$CT=\ T_1+T_2$

17SPIRAL CURVE
Distance along
tangent to any point
on the Spiral
$Y\ =\ L-\ \frac{{\ L}^5}{40\ R^2\ {L_s}^2}$

18SPIRAL CURVE
Offset Distance from
Tangent to any point
in the Spiral
$x\ =\ \frac{L^3}{6\ R\ L_s\ }$

19SPIRAL CURVE
Spiral angle from Tangent
to any point on the Spiral
$\theta\ =\ \frac{L^2}{2\ R\ L_s\ }$

20SPIRAL CURVE
Deflection Angle from
TS to any point
on the spiral
(i)
$i\ =\ \frac{\theta}{3\ }$

21SPIRAL CURVE
Ratio of
$i\ and\ i_s$
$\frac{i}{{L\ }^2}=\frac{i_s}{{L_s}^2\ }$

22SPIRAL CURVE
Tangent Distance (TS to PI)
${(T}_s)$
$T_s=\ \frac{L_s}{2}+\ \left(R+P\right)\ tan\left(\frac{I}{2}\right)$

23SPIRAL CURVE
Length of Throw
(P)
$P=\frac{X_c}{4\ }\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ P=\ \frac{{L_s}^2}{24\ R}$

24IN VERTICAL CURVES ALWAYS CREATE FIGURE THOROUGHLY
and REFER TO IT FOR THE SIGN CONVENTION
IN VERTICAL CURVES ALWAYS CREATE FIGURE THOROUGHLY
and REFER TO IT FOR THE SIGN CONVENTION
25
SPIRAL CURVE
External Distance
$(E_s)$
$E_s=\frac{R+P}{cos\ \left(\frac{I}{2}\right)}-P $

26Degree of Spiral Curve
at any point
$\frac{D}{D_C}=\ \frac{L}{L_S}$

27Desirable Length of Spiral
$L_S=\ \frac{0.036\ v_{\left(kph\right)}^3}{\ R}$
28Super Elevation Rate
$e\ =\ tan\ (\theta)$
$tan\ (\theta)\ =\ \frac{v_{\left(m/s\right)}^2}{g\ R_{(m)}}$

29Maximum Velocity
in a road with super-elevation
$e+\ \mu\ =\ \frac{{v_{max}}^2}{g\ R}$

30Minimum Velocity
in a road with super-elevation
$e-\ \mu\ =\ \frac{{v_{min}}^2}{g\ R}$

31Rate of Change in
Centripetal Acceleration
$q_{(m/s^2)}=\ \frac{v_{\left(m/s\right)}^3}{\left(R\ L_S\right)_{(m)}} $
32Symmetrical Vertical Curve
CONCEPT
33Symmetrical Vertical Curve
Elevation of PI relative
to the Curve (Road)
$H=\ \frac{L}{8}\left(\ \left|g_1\right|+\left|g_2\right|\ \right)$

34Unsymmetrical Vertical Curve
Elevation of PI relative
to the Curve (Road)
$H=\ \frac{\left(\left|g_1\right|+\left|g_2\right|\right)\ L_1\ L_2}{{2\ L}_T}$
$H=\ \frac{\ L_1\ }{2}\ \left(\left|g_1\right|+\left|g_3\right|\right)$

35Unsymmetrical Vertical Curve
Elevation of own PI relative
to the Curve (Road)
$h_1=h_2=\ \frac{\ H\ }{4}$

36Unsymmetrical Vertical Curve
Slope of Common Tangent;
g3
$g_3=g_1-\ \frac{\ 2H\ }{L_1}$
$g_3=\ \frac{\ g_1\ L_1\ +\ g_2\ L_2\ }{L_T}$
37Unsymmetrical Vertical Curve
Locating the summit/ trough
$If\ \ \ \left(g_1\ L_{1\ }\right)\ >\ 2H,\ \ therefore\ ...$
$S_2=\ \frac{\ g_2\ \left(L_2\right)^2\ }{2H}$
$S_1=L_T-{\ S}_2$

38Unsymmetrical Vertical Curve
Locating the summit/ trough
$If\ \ \ \left(g_1\ L_{1\ }\right)\ <\ 2H,\ \ therefore\ ...$
$S_1=\ \frac{\ g_1\ \left(L_1\right)^2\ }{2H}$
$S_2=L_T-{\ S}_1$

39Earthworks
Cross Sectional Cut
40Earthworks
Cross Sectional Fill
41Earthworks
Cross Sectional Cut and Fill
42Earthworks
Volume by End-Area Method
$({\ V}_e)
${\ V}_e\ =\ \frac{L}{2}\left({\ A}_1+{\ A}_2\right)\ $
43Earthworks
Volume by Prismoid Formula
$({\ V}_p)$
${\ V}_p\ =\ \frac{L}{6}\left({\ A}_1+{\ 4A}_m+{\ A}_2\right)\ $

44Earthworks
Prismoid Correction
$({\ C}_p)$
${\ {{\ C}_p=\ V}_e\ -V}_p$
$C_p=\ \frac{L}{12}\ \left(c_1-c_2\right)\left(d_1-d_2\right)$

45Earthworks
Volume by Truncated Prism
$V\ =\ A\left[\frac{1\ \left(\sum{\ h}_1\right)+\ 2\ \left(\sum{\ h}_2\right)+3\ \left(\sum{\ h}_3\right)\ +4\ \left(\sum{\ h}_4\right)}{4}\ \right]\ $
