Report on how to design high way on a hilly area

Introduction

Romans was the people who started building long length roads, roads that connected to Europe, who saw the ability to move quickly as essential for both military and civil reasons. The Roman approach to road design is essentially the same as that in current use. The roads were constructed of several different layers, increasing in strength from the bottom. The lowest layer was normally rubble, intermediate layers were made of lime bound concrete and the upper layer was a flag or lime grouted stone slabs. The thickness of the layers was varied according to the local ground conditions.

            Highway designs vary widely and can range from a two-lane road without margins to a multi-lane, grade separated freeway. In law the word highway is often used as a legal term to denote any public road, ranging from freeways to dirt tracks. An interconnected set of highways can be variously referred to as a "highway system", a "highway network" or a "highway transportation system".

            This report consists of a highway which connects two highways A to B, through a declining hilly area, and this area needs to be cut and fill. Consist of a sag curve and crest curve. The minimum gradient through the road is 7%. And the first 50m is 0% and straight.

Speed parameter and route selection

 Route selection

Human beings are natural effort minimizes, notably when it involves moving around. When given the opportunity, they will always try to choose the shortest path to go from one place to another. Transportation, as an economic activity, replicates this process of minimization, notably by trying to minimize the friction of distance between locations. Shorter times and lower costs are looked upon by individuals as well as by multinational corporations. For an individual, it is often only a matter of convenience, but for a corporation it is of strategic importance as a direct monetary cost is involved.

The Road we have designed is 864 meters in length.

 Speed parameter


Speed or velocity, it measure how much of distance a particle or vehicle moves in a period of time. In human there are three thing which influence driver choice of speed; Personal; which means how tired he she is or how occupies he/she is,  Vehicle; the type of vehicle he/she is driving, External; this is things outside the vehicle, like how the road is, how the weather is.

The design speed of this road is 80 Km/H from A to B of 864 meters.

 Design calculations

 Horizontal curvature and alignment

Design speed of road, V =  80 Km/h,                         e = 0.07 Max,              f=0.26

R_min     =                 V²              .           

                   127 ( e_max + f_max)              

R_min     =                 80²              .           

                   127 ( 0.07 + 0.26)                       

R_min     =       157.5 M



Rate of rotation
   LSD    =       (n.e)     x    VD


                     0.025         3.6
  LSD    =       (0.03 x 0.06)     x    80


                          0.025                  3.6
       LSD    =       80 M




Plan transition length
       LT      =          2/3 x LSD


       LT      =          2/3 x 80


       LT      =          53 M




Chainage at TP leading
       ChTP1             =          130+81 = 160 Tan 52


            =          132.97 M
       ChTP1             =          132.97+145  = 277.97


            =          278 M

Vertical Alignment

Crest curve

A         =          0 – (-7)

            =          7

K = 24,            V =  80 Km/h

Min crest =      7 x 24 = 168 m

Ha       =          912 + 0                        =912
Hb       =          912 – 0.07x 168/2       = 906.12

Hc       =          (912 +906.12)/2          = 909.06

Hd       =          (909.6 + 912)/2           = 910.53

Cha      =          140 – 168/2                 =56 m

Chb     =          140+168/2                   =224 m



   Hp     =          Ha +[(p/100) X] + [ (-A/200L) X2]


          =          912 + 0 - 0.0033


           =          911.99


Table 1 ; Crest curve in every 20 m intervals

Chainge	x	ha	(p/100)	x	A/200L	x2	Hr
56	4	912	0	4	-0.00021	16	912.00
60	24	912	0	24	-0.00021	576	911.88
80	44	912	0	44	-0.00021	1936	911.60
100	64	912	0	64	-0.00021	4096	911.15
120	84	912	0	84	-0.00021	7056	910.53	ok
140	104	912	0	104	-0.00021	10816	909.75
160	124	912	0	124	-0.00021	15376	908.80
180	144	912	0	144	-0.00021	20736	907.68
200	164	912	0	164	-0.00021	26896	906.40	ok

sag curve

A         =          -7 – (3)

            =          -10

sag       =          200 m adopt

Ha       =          865.7  + 0.07x100       = 872.7
Hb       =          865.7  + 0.03x 100      = 868.7

Hc       =          (872.7  +868.7)/2        = 869.92

Hd       =          (869.92+ 865.7 )/2      = 867.92

Cha      =          768 – 200/2                 =668 m

Chb     =          768+200/2                   =868 m
 Chd   =          768

Table 2 ; Crest curve in every 20 m intervals

Chainge	x	ha	(p/100)	x	A/200L	x2	Hr
668	20	872.7	0.07	20	-0.00025	400	871.40
688	40	872.7	0.07	40	-0.00025	1600	870.30
708	60	872.7	0.07	60	-0.00025	3600	869.40
728	80	872.7	0.07	80	-0.00025	6400	868.70
748	100	872.7	0.07	100	-0.00025	10000	868.20
768	120	872.7	0.07	120	-0.00025	14400	867.90	ok
788	140	872.7	0.07	140	-0.00025	19600	867.80
808	160	872.7	0.07	160	-0.00025	25600	867.90
828	180	872.7	0.07	180	-0.00025	32400	868.20
848	200	872.7	0.07	200	-0.00025	40000	868.70	ok

Earth work volume calculation 

From the graph there is around 74 fill in section and 3 cut section.

Cut and fill ratio         =     1 : 24.6

Volume of fill is;

=          74 – 3  = 71 nos

=          71 x 12 x 20

=          17,040 M³ of soil for fill

Volume of cut is;

=          3nos

=          3 x 12 x 20

=          720 M³  of soil to be cut

 Reference

[1] Traffic and Highway engineering, Nicholas J garber, lester A Hoel, 3^rd edition.

[2] Highway Engineering, Martin Rogers

[3] http://people.hofstra.edu/geotrans/eng/ch2en/meth2en/ch2m2en_2ed.html