Civil Engineering: Solutions for Lot 14 Survey, Layout, and Excavation

This document provides solutions to a civil engineering assignment focused on Lot 14, addressing various aspects of surveying, building layout, and site preparation. It includes calculations for true dimensions using Pythagoras' theorem, determining angles and distances for building placement, assessing the total fall across a building footprint, and outlining the steps for setting out a building using profiles and string lines. The solutions also cover formwork construction to achieve the required finished floor level, calculating the approximate volume of bulk excavation, and determining the grade of a vehicle crossing. Additionally, the document addresses stormwater detention, including the calculation of pit dimensions to meet capacity requirements, all adhering to specific site constraints. Desklib offers a platform to explore similar solved assignments and resources for students.

SOLUTIONS
1. You have taken a measurement on Lot 14 from the south west corner to the
north east corner of the allotment. The measurement you obtained from your
tape measure, laying it on the ground, was 43,866 mm, measured to the
nearest millimetre.
a) Is this the true dimension for the distance between the two pegs on plan
view? This is not the true dimension.
b) If the answer to part ‘a’ is no, what is the true dimension on plan view and
explain the reason for the difference? (use Pythagoras’ theorem)
We can calculate the true dimensions as follows:
= Square root (40002+180002) = 43 863.4244mm
The discrepancy arises due errors such as: systematic errors, equipment error and reading error
(Parallax).
2. You have engaged a surveyor to carry out an identification survey of Lot 14
(peg the four corners of the boundaries) and to peg the 6m building line (the
setback of the house from the front boundary).
a) From the North West corner of the allotment, calculate the angle and
distance to the north west corner of the proposed building
Sin ɸ= 6000/7211.10= 0.8305, ɸ = Sin-1(0.8305) = 56.31o
The distance = square root (60002+40002) = 7211.10mm
b) From the contours determine the total fall across the footprint of the building
the highest point is at: 0.30m and the lowest point at 0.05 hence the total fall across the footprint:

=0.30-0.050= 0.25m
c) Assuming you will construct a level, rectangular platform for the construction
of the building, extending 1m beyond the external walls of the building, what
are the approximate dimensions of this platform?
Approximate dimensions: l= 16910mm
W= 1000mm
d) Utilizing the surveyors pegs, outline, step by step, how you would set out
the building using profiles and string lines to allow any excavation,
formwork/slab construction to be accurately completed.
 The Northwest corner point, locate the first peg and attach the string to it
 Running with the string, move it to the next peg located at the north east corner point and
measure the length
 Now, turn to the opposite corner point and repeat the same procedure moving the string
to the next peg point and demarcating it. Once this is established to be exactly the area
that was marked for excavation in the plan, we move on with the excavating activity.
e) Outline how you would construct the formwork to achieve the required
Finished Floor Level
-The purpose is to construct a formwork that holds the concrete until it properly cures and this is
implemented as follows:
-The design is properly done by considering the strength characteristics including dead, live and
hydrostatic loads.
-Consider the gang size as during concrete pouring for column and slabs, they exert sufficient
load stress on the formwork
-Identify the suitable wall tying system; this should be such that the opposite faces have their
forces balanced

-Then we form construction points at right angles with keyed mechanism for jointing
-Lastly, we ensure that the slip form system established can withstand the downward, upward
and sideways movements as the pouring of concrete ensues.
f) From finished floor level shown on the drawings (RL 0.000), subtract
200mm to allow for the slab and sub grade thickness. This reduced level is
sometimes referred to as the bulk excavation level (BEL). From this BEL,
the contours, and the dimensions of the rectangular platform, calculate the
approximate volume of the bulk excavation for the building
The approximate volume is calculated by considering the excavation plan is rectangular and
extends through the length of the building hence vol.
= 0.2x 1.61x0.6= 0.1932m3
3. Assuming the RL at the top of the vehicle access (crossing) is 0.030, the top of
kerb is -0.030 and the kerb height is 100mm,
a) Draw a longitudinal section of the vehicle crossing from the kerb to the front
Boundary Lot 14
Check the attached pdf file for the longitudinal section
b) Determine the grade from the top of the crossing to the bottom of kerb as a
percentage and a ratio.
The grade plane= (100+30)/2= 65.00
Percentage= 30/65 x100= 46.15%
The ratio: 6:13

4. The client on Project 1 has requested provision be made for storm water
detention on the site. The hydraulics engineer has calculated the capacity of
the pit necessary for the site to be 23,000 litres.
Calculate a pit dimension that would meet this capacity requirement and that
can be constructed within the front area of the property; that is, in the area
between the front boundary and the front building line. Do not position the tank
within 3m of the building. (1000L = 1m3)
Capacity= 23000litres= 23m3
Now, assume the pit is perfect cylindrical:
V= 1/4πd2h, for maximum capacity, let d=2h
Hence V= 1/4π(2h)2h= 3.142h3
H= (V/3.142)1/3 = (23/3.142)1/3 = 1.94m=1940mm, d= 2x1.94= 3.88m= 3880mm