EXPERIMENT NO -7
PRINCIPLES OF
HEIGHTS AND DISTANCE USING
SURVEYING - WHEN BOTH ANGLES ARE IN DEPRESSION
TACHEOMETRIC
Alm: To determine the elevation of an inaccessible point when both angles are in
by tacheometric surveying.
Instruments requirod: Theodolite, tape, cross staff, arrows, tripodetc.
depres ion
Principlo: The Tacheometer is an instrument which is generally used to determine the
horizontal as well as vertical distance It can also be used to determine the elevation f
various points which cannot be determine by ordinary leveling When one of the
horizontal and staff held vertical then the RLs of staff station can be sight is
determine in ordinary leveling But if the staff station is below or determined as We
collimation then the elevation or depression of such point can be above the line of
vertical distances from instrument axis to the central determined by calculating
elevation or depression made by line of sight to the hair reading and taking the angle of
instrument axis. instrument made by line of sight to the
Obsorvatlons and
Calculatlons: With the same
notations as earlier
V=D tana2. (1)
V-g =D tana1, (2)
Subtracting(2) from (1), we
get S= D tand2 - Dtana1
D=
V=D
tana?
Elevation of Q= (Elevation of station + h) -v -r
Procedure:
1. Set up the instrument atPand levelit accurately bycarryout rie
adjustments.
2. Set vernier reading to zero
3. Take the first staff
making line of sight horizontal. instrument and
reading on Benchmark and determine height of
let it beh.
to be calculated.
4 Then sight the telescope towards the staff station whose RLs are downward
or and
5. Measure the angle on sight isinclined upward
vernier
also note the three crosshair readings.
distance
O.DeleEImine the R.Ls of various points by calculatingthe vertical
is=
7.
Result: The elevation of an inaccessible point
8.
EXPERIMENT NO -8
DETERMINATION OF STADIA CONSTANTSOF TACHEOMETER
Aim: Todetermine the multiplying and additive constant of a given
theodolite Instruments required theodolite,tape, ranging rods, levelling
staff, arrows etc. Procedure:
1 Stretch the chain in the field and drive pegs at 1Om, 20m interval.
2 Set the theodolite at the zero and do the temporary
3 Keep the adjustments.
staff on the pegs and observe the corresponding staff
4
horizontal site.
Substitute the values
of distance (D) and staff intercept (s) for different
intercepts with
equation D = ks + C. where k &s are the
tacheometric constants.
in the points
multiplying constant &C is the additive constant.
5. Sove the
is the
Successive pairs of equations to get the value of k & Cand find out
average of these values. the
Observations and calculations:
itercept.s
-D, A B
Instrumen Staff Distance
t Station Statio
Stadia Reading Stadia
Top Middle
n Bottom Intercep
t
(S)
D= KS +C
D1= K.S1 +
C .(1)
C... .(2)
D2 = K.S2 +
find K &C
Solve Two Equations &
RESULT: Multiplying constant, K=
Additive constant, C =
EXPER WENT-9
CURVE SETTING- RANKINES WETHOD
INSTRUWENTS REQURED: Cross stef amoNS COCSs tape tod st
FIELD PROCEDURE:
T Locate PC (T1) PI T2) anc PL
< Set up the trecdoite eectyat T1 ard mae is
teUOery Lsets
J Set up vemier Ato zeo ard yses te PICamo eione wete
4 ReeSse üe uDoer ate ard set
reec A.Tre line of siaDts tus te wemie Ao
T1a directed zOg
3 Hoic tte zerota0e
ttt ekea
aTOW il itis bsected by he disierce C1 T12and sWrg re tape wth a
Curve. eodoite Tris estaishes te first port in te
Set thesecanc detecaar
arcie 2 Or the scaie so tret ime of
7Witnzero of he of re taoe teid ata c sigt is set aorg T1
an arcN t e oter
distance-ab).
b. is
swing the tape 0out a il te aroW is
enc (hord
estaiishes thesecond point b on ecure. Dseted bythetheodoite t
8) The same steos are
reoeeted il relst punt T2 is reaces.
CALCULATIONS:
chord T,a, then
iengm orthe frst chord Le,
should Be same).
N E N N N N a nhat aY the radus ofthe cuve
using RANKINE'S method.
RESULT: The cuve is plotted by
EXPERIMENT NO 11
SETING OUT WORK8 FOUNDATION MARKING
Aim: Toset out the foundationmatking tor th6 proposed constructiorn of ths buildirng
Instrumonts roquired Theodolite, tape, fangin4 rods, strings, arroWs etG..
Principle the apparatus of ths marking on the side, ths (rtre lines of ths foundation of
the building is called settinG out of atoundatio
Procedure:
1. Acentre line sketch of building is prepared,
? The base lin6 is Get out with r6f6r6nc6 to qiven roferenCO points
3 The nds of th6 centre lineof the walls point A andpoint B frorrn the base line are
marked
4. As the Gnd marks A, B, Cotc. ars distributsd during excavation stakes are fixed at
I, m, n stc,, alitle away about 2 to3 m frorn end rmark and aCCurately using string.
5 The Contre in6 for all the otthor walls AD, BC otc.. are rmarked by dropping
psrpendiclar byusing chain or tape 345 rnsthod for an irnportant and big buildinc
when sides ars long a theodolits rmay be ermployed to accurately set out and range
the lins,
6. For overy wall the pogs aro drivon a little way frorm the marking end and fie
accurately with a string.
7, The diagonals ars rnsasured and checked with the corresponding calculated lengt
RESULT: Thus the contre lins planned by being marked on the ground.
