BCS205S Engineering Surveying

Subject Code :
BCS205
Country :
AU
University :
Engineering Institute of Technology

Project background:

The site is a land property with a frontage road. The land was surveyed including level survey and the survey map has been prepared with contours as attached.

(Contour: Contour are lines on a map representing an imaginary line on the land surface connecting all the points of same elevation. It is strongly advised to do some research though internet on what is contour, how to draw contours from level survey, how the level condition of ground surface is represented by contours map etc).

2 m x 2 m grids are drawn on the map, as graph, to work on the printed map.

A road, as a simple access to the property development, will be constructed on the land with the cross section geometry:

Width of carriage way 8 m
Cross fall 3%
Batter to existing surface with slope 1 in 2

The scope of works:

Set-up and draw vertical profile of proposed road centerline alignment.
4 cross-section profiles including start and end.
Calculation of area of filling of cross sections.
Calculation of volume of filling.

Setting up alignment

Instructions:

Choose a straight centreline alignment of the road in between 40 to 70 m (along a line of the grid).
Put chainage marks at every 10 m and write the chainage at every 20 m interval.
Read the RL of from the contour on the map at 10 m interval and note. Use linear interpolation between the contour lines and visual approximation in this case is accepted.
Plot a graph of the existing land profile along the road centreline.

Calculate the average slope i.e. slope of start and end of the ground surface along the alignment.

[Example: In this case, Slope = (88.82 - 84.52) * 100 / 60 = 7.16%]

Choose the gradient of the proposed road by rounding the average slope to the upper 0.5%. [Example: In this case, 7.5% is selected]
Select the level (RL) of the start of the alignment higher than the ground surface about 1.5 to

2.5 high and a round it.

[Example: In this case 86.0 m is selected]

Calculate the levels (RL) of the whole proposed road alignment at 10 m interval based on the selection of the level of the start and gradient.
Fill up the data as per table below:
- Plot the longitudinal profile of the proposed road on the same graph paper where you have already plotted the profile of existing land surface.

Setting up cross-sections

Select 4 chainages for drawing cross-sections including start and end, possibly at regular interval. You need to draw cross-sections of the proposed road showing vertical profile of the land surface at these four selected chainages.
To plot the cross-section, draw a line perpendicular to the road centreline at the selected chainage and read the levels from contour map at centreine, 4 m, 8 m and 12 m distances both sides.
Plot the data to draw profile of the existing land surface along cross-sections at the chainage.
Then draw the profile of the proposed road:

First locate the design RL of the proposed road of previous selection.
Calculate the RL at 4 m from the cross section at 3% downgrade, which is the RL at the edge of carriageway.
Use ruler to draw the batter line at slope 1:2 from edge of carriageway to intersect existing ground surface.

Calculate area of fill from plot of cross-sections

Divide the cross-section graphically into suitable shapes and calculate the area of fill from the cross-section plots, using approximate dimensions from the graph.
Complete the same for all four cross-sections.
Show area calculation.

Calculate volume of the road construction

Calculate total volume of fill by using the formula