INTRODUCTION
Construction surveying (known as “lay-out” or “setting-out”) is to stake out reference points and markers that will guide the construction of new structures such as roads or buildings. Construction surveying is generally performing the following tasks:
• Survey existing conditions of the future work site, including topography, existing buildings and infrastructure, and even including underground infrastructure whenever possible; (for example, measuring invert elevations and diameters of sewers at manholes).
• Stake out reference points and markers that will guide the construction of new structures;
• Verify the location of structures during construction;
• Conduct an As-Built surveying: a survey conducted at the end of the construction project to verify that the work authorized was completed to the specifications set on plans.
OBJECTIVE
• Carry out accurate setting out.
• Carry out all the necessary calculations to establish the setting-out points. • Work as a team in order to execute a large scale surveying work.
• Produce and present an engineering report on an engineering survey work.
THEORY
Setting-out is the translation of construction plans into physical point on the ground that can be used as a basis for the actual construction. The results of construction surveying are seen in almost any urban, suburban and rural. Almost any roadway, building or other man-made improvement probably had some amount of construction surveying involved. Construction surveying provides not only the horizontal location of new structure, but also the vertical information required to ensure that surfaces drain or pipes flow as required. The layout, or stakeout, survey consists of locating and marking (staking) horizontal and vertical control points to guide construction crews, and giving line and grade as needed to establish additional control points and to reestablish disturbed stakes.
The setting out surveying will start with calculates information from the drawings to ensure that:
• Buildings can be positioned correctly along with all the necessary structural components within it.
• All the structural components are built to the correct level.
• Lines and levels for structures, roads, drainage and earthworks are provided. When a site layout design has been established, all this information is accurately transferred onto site. Using the latest survey instruments the setting points can set-out on site as required, base to the design drawings and design co-ordinates. In addition, the setting-out work also include the check surveys at various stages throughout the construction process: which can involve the independent checking of points set-out by others, where quality monitoring is required.
EQUIPMENTS
Total station Prism Pole and mini prism Tripod
Nails and hammer
FIELDWORK PROCEDURES
1. Preparation and Planning
a) The setting out of building corner performed according to the position taken from a topographic and detail plan (tachometric plan).
b) Position of the proposed building identified by reece the site according to site plan. c) The nearest traverse station to be used identified as setting out reference point. d) Corner of the building to be established on the ground.
e) Data of setting out to be calculated.
2. Field Procedures
a) Instrument station selected based from pre-comp plan. b) Instrument station should be the nearest to project site.
c) Instrument at station P1 and prism at station P2 set-up as reference bearing. d) The bearing and distance recorded from station P1 to P2 in the setting out form. e) Bearing station P1 is then set to point f to determine the point f location.
f) The distance measured from station P1 to point f using tape then precisely mark the point using mini prism.
g) The same method used to mark all the point from station P1 to b, c, d, e and f.
DATA TABLE
6 points was located near to KM Chalet P1 & P2
STN TO BEARING HZ. DISTANCE F A 270 00 14 4.000 B 326 18 50 7.211 D 326 18 50 3.605 C 341 34 08 6.325 E 00 00 14 3.000 B F 146 18 50 7.211 D 146 18 50 3.615 C 89 03 20 2.000 A 180 02 50 6.000 E 127 14 10 5.000
a = 115 22 17 b = 171 40 53 c = 186 56 11 d = 205 22 16
To find the length :
fb and fc by using phantagaros theorem: fb = √ (62 + 42) = 7.211 m
fc = √ (62 + 22) = 6.325 m
while fc = ½ df df = 3.162 m
DISCUSSION
¤ The observation is important before start setting out because we would know where the proposed building should be located properly within our boundary line without sighting disturbance.
¤ We are suggested to get the measurement for bearing and distance for the proposed building by AutoCAD before we start our field work.
¤ Bubble in the instrument has to be centered correctly in order to get an accurate result
¤ For the first check we have to use a measuring tape to ensure the measured distances are the same with the distances given.
¤ For the second check we have to set our total station at station f and point to every corner of the proposed building to ensure the bearing and distance are the same with the given ones.
CONCLUSION
¤ Based on the result that we get, our data is fulfill the allowable measurement which is the bearing not more than 30” and distance is less than 30mm by comparing the obtained data with measured data.
¤ AutoCAD plays an important role for setting out because it provides an exact measurement for the proposed building before we transfer the proposed building to our field work.
¤ Our proposed building didn’t overlap with the building surround it in the field work and autoCAD. Location and calculation for the proposed building was done correctly in the field work with the bearing and distance measurement that we get in autoCAD. Hence, objective achieved.
REFERENCES
1. Kejuruteraan Geomatik II (2006) Masiri Kaamin dan Abd. Shukor Sarif.Terbitan UTHM
2. Setting Out (2003) from Makmal Bahan and Geomatik. 3. Amalan Geomatik Pemancangan Tanda
