HEIGHT OF INSTRUMENT METHOD

HEIGHT OF INSTRUMENT METHOD POINTS TBM POINT 1 POINT 2 POINT 3 POINT 4 POINT 5 BS(m) IS(m) FS(m) HI(m) RL(m) 98.20 THE TBM VALUE FOR THIS PROJECT IS 98.20 METERS IS 1.20 METERS THE INTERMEDIATE SITE IS READINGS BEFORE THE FIRST CHANGE POINT ARE 1.16 AND 2.01 METERS 2.01 THE OTHER READINGS ARE FORESIGHT 1.9 0 BACK SIGHT 1.33 INTERMEDIATE SIGHT 1.54 AND FORESIGHT 1.7 6 MAY TESTS USING THE HEIGHT OF WE SHOULD NOTE THAT THE HEIGHT INSTRUMENT IS CALCULATED ONLY AT THE WHERE BACKSIGHT WERE TAKEN THEREFORE HEIGHT OF INSTRUMENT EQUALS REDUCED PLUS BACKSIGHT EQUALS 98.20 + 1.20 HI = RL + BS HI = 98.20 + 1.20 HI = 99.40 LEVEL 99.40 98.20 98.24 97.39 97.50 97.29 97.07 HAVE OBTAINED THE HEIGHT OF INSTRUMENT AT THAT POINT WE CAN NOW REDUCED LEVELS OF THE OTHER POINTS WHERE READINGS WERE WHILE THE INSTRUMENT WAS STILL IN THE SAME POSITION PLEASE NOTE THAT YOU CAN TAKE AS MANY INTERMEDIATE IS READINGS AS POSSIBLE BEFORE CHANGING THE INSTRUMENT POSITION YOU CAN CLEARLY SIGHT THE STAFF ACCURATE READING RL = HI - STAFF READING POINT 1: RL = 99.40 - 1.16 RL = 98.24 EQUALS 99.40 - 1.16 IS EQUAL TO 98.24 M POINT 2: RL = 99.40 - 2.01 RL = 97.39 EQUALS 99.40 - 2.01 IS EQUAL TO 97.39 POINT 3 THIS POINT WE HAVE A FORESIGHT ENDING THE FIRST INSTRUMENT SETUP RL EQUALS 99.40 POINT 3: RL = 99.40 - 1.90 RL = 97.50 EQUALS 99.40 - 1.90 IS EQUAL TO 97.50 M NOW THE FIRST INSTRUMENT SETUP HAS FORESIDE AND WE HAVE MOVED THE INSTRUMENT POSITION POINT WE NOW TAKE OUR FIRST READING INSTRUMENT POSITION TO POINT 3 WHICH IS CALLED AGAIN SINCE WE HAVE A NEW WE NEED TO CALCULATE A NEW HEIGHT OF INSTRUMENT FOR THIS SETUP SO REMEMBER WE NEW REDUCED LEVEL FOR THAT POINT SO IT IS THE REDUCED LEVEL OF POINT THREE PLUS THE BACKSIDE TO POINT 3 WHICH IS 97 POINT 50 + HE = RL + BS HI = 97.50 + 1.33 HI = 98.83 POINT 3: RL = 99.40 - 1.90 RL = 97.50 TO 98.83 POINT 4 RL POINT 4: RL = 98.83 - 1.54 RL = 97.29 EQUALS 98.83 - 1.54 IS EQUAL TO 97.29 9.5 RL EQUALS POINT 5: RL = 98.83 - 1.76 RL = 97.07 98.83 - 1.76 = 97.07 AND THAT'S HOW WE CALCULATE REDUCED USING THE HEIGHT OF INSTRUMENT METHOD FROM THE TBM WE CALCULATE OUR FIRST HI DETERMINE THE RLS OF THE OTHER POINTS CHANGE POINT WE CALCULATE A NEW HI AND CONTINUE THE PROCESS UNTIL WE COMPLETE THE LEVELING IF THIS EXPLANATION HELPED YOU UNDERSTAND LEVELING BETTER LIKE SHARE AND FOLLOW FOR MORE SIMPLE SURVEYING TUTORIALS SEE YOU IN THE NEXT ONE