Engineering surveying F17 CIVL 0002 Session- AA Lab Report 1 Experiments used 1. Two peg test 2. Booking and determining reduced levels using HCP and rise and fall method 3. Digital level Student name: Mohammed Hilal AlBalushi Id: 16F15722 Submitted To: Vineetha Anil 1 Table of contents Introduction Procedure Observation and Calculations Discussions References Page No. List of tables Table 1 Table 2 Table 3 Table 4 Table 5 Page No. List of figures Page No. 2 1. INTRODUCTIONLevelling is a commonly used way in all construction sites before starting any project just to know the exact level of the area they are going to work on just to make sure that the land is in level and does not have high difference in gradient. It can also be defined as the art of representing and determining the elevations or the relative heights of different points on the surface of this earth which deals with measurements at a vertical plane. Levelling results can be used in so many ways like designing railways, highways, bridges and so on, they all need levelling in the beginning because of the slope they need to have. In this report we are going to explain 3 practical’s done by the students regarding the levelling lesson, what has been done, how did we do it and and what we have learned from it. The first practical was the Two Peg Test which was done to test the collimation error of the manual level used. Second, was a practical called Booking and Determining Reduced Levels using height of plain collimation method and the rise and fall method. It was done by us just to carry out levelling and determining the RL data using the height of collimation method and the rise and fall method. The third practical done was levelling using digital level and to determine the RL data using the height of collimation error and the rise and fall method. In any levelling process you should have some instruments to use to use, you may fix it mostly at the construction sites. The instruments used were the Tripod stand, Manual staff, Manual and Digital level, Plumb bob and a measuring tape. The tripod stand is a three legged support for the level, you can adjust the legs of the tripod stand for the required vertical height, and once the tripod is shifted from its place it must be set up again by loosen the screw and adjust again. The main function of this instrument is to ensure a stable instrument setup for reliable measurements. The digital level, it is a professional levelling device used by all contractors, land surveying professionals and engineers who demands accurate levelling every time. It is easy to set up and use, all what you have to do is to make sure that the spirit bubble is in the centre of the black circle. Manual staff is a tool used to measure the elevation measurements in the field works. The rod can be made of wood, fiber glass and metal. It is also used to determine the relative height at different points in the given area under survey. The plumb bob is a small instrument used to know the centre of all other instruments (tripod with the digital level fixed) just by hanging it in the hanger under the digital level. 3 2. PROCEDURE2.1- practical 1, First we collected the instruments from the lab and went to the field, then we started fixing the manual level on the tripod and levelled it. In set up 1 we put the manual staff 10m away from the manual level and took the reading, then we moved the staff to the opposite side and took the reading again. In setup 2 we levelled the manual level again and put the staff 2m away and took the reading, then we took it to 22m and recorded the data. In the end we calculated the error. 2.2- practical 2, We started levelling the manual level and and put the staff on the bench mark given to us. We took the reading of all the points on the plan we made including two change points. We levelled the manual level again at every time we change its place. 2.3- practical 3, We levelled the digital level, and we measured 60m by the measuring tape along the way in front of it. We started taking readings of every 5m till we reached 60m with 1 change point. The results were calculated by the two methods. 4 3. OBSERVATION AND CALCULATION3.1- practical 1, Level Position B B B1 B1 Staff Position A C A C Sighting Distance 0m 30m 0m 33m Staff Reading 1.650m 1.450m 1.210m 1.200m S1= 1.460 S2=1.440 S3 =1.445 S4=1.440 Collimation error = (S1-S2) - (S3-S4) = (1.460-1.440) - (1.445-1.440) Collimation error = 0.01 3.2- practical 2, Height Of Collimation Error method: BS 1.000 IS FS 1.475 1.550 1.475 1.570 1.435 1.445 1.410 1.230 1.210 1.200 0.920 HCP 421 421 421 420.905 420.905 420.905 420.905 420.925 420.925 420.925 RL 420 419.525 419.450 419.430 419.470 419.460 419.495 419.695 419.725 420.005 Arithmetic Check ∑BS - ∑FS = Last RL - First RL 3.705-3.700 = 420.005-420 0.005=0.005 5 Rise and Fall method: BS 1.000 IS FS Rise (+) Fall (-) 0.475 0.075 0.02 0.04 0.01 1.475 1.550 1.475 1.570 1.435 1.445 1.410 1.230 0.0035 0.02 0.03 0.28 1.210 1.200 0.920 RL 420 419.525 419.450 419.430 419.470 419.460 419.495 419.695 419.725 420.005 Arithmetic Check ∑BS - ∑FS = Last RL - First RL 3.705-3.700 = 420.005-420 0.005=0.005 3.3- practical 3, Height Of Collimation Error Method: BS 0.4970 IS FS HCP 766.4970 1.5897 766.3536 1.2811 1.5832 1.5677 1.5500 1.5563 1.4463 1.3878 1.4360 1.4310 1.3935 1.4049 1.4211 1.4843 RL 766.000 765.2159 764.9138 764.9293 764.9470 764.9407 764.9073 764.9658 764.9176 764.9226 764.9601 764.9487 764.9325 764.8693 Arithmetic Check ∑BS - ∑FS = Last RL – First RL 1.9433-3.0739 = 764.8693-766.000 -1.130 = -1.130 6 Rise And Fall Method: BS 0.4970 IS FS 1.2811 1.5832 1.5677 1.5500 1.5563 1.4463 Rise (+) Fall (-) 0.7841 0.3021 0.0155 0.0177 6x10-3 0.0334 1.5897 1.3878 1.4360 1.4310 1.3935 1.4049 1.4211 0.0585 0.0482 5x10-3 0.0375 1.4842 0.0114 0.0162 0.0631 RL 766.000 765.2159 764.9138 764.9293 764.9470 764.9410 764.9076 764.9661 764.9179 764.9229 764.9604 764.9490 764.9328 764.8697 Arithmetic check ∑BS - ∑FS = Last RL – First RL 1.9433-3.0739=764.8693-766.000 -1.130 = -1.130 7 4. DISCUSSION4.1- practical 1, The two peg test is an easy test which you can learn from it how to fix all the levelling instruments in the correct way and how to take the reading and calculate the collimation error. 4.2- practical 2, In practical (2) we learned and knew more about levelling like how to draw your plan which you will follow and how to record your accurate readings and the most important is learning how to calculate the reduced levels using the height of collimation error and the rise and fall methods. 4.3- practical 3, In practical (3) we used the digital level for the first time so we got to know what is the correct way to use it and how to take the readings. We learned how to know that out readings were accurate or gone wrong by checking the reduced levels using the height of collimation error and the rise and fall methods. 8 5. REFERENCES- 9
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