Surveying 2 Fieldwork 2

ADVANCED SURVEYING FIELD MANUAL

FIELD WORK NO. 2 LAYING OF A SIMPLE CURVE BY TAPE ALONE (INCREMENTAL CHORD AND TANGENT OFFSET METHOD)

COURSE AND SECTION: CE121F – A2 SUBMITTED BY:

SN: 33 NAME: TRINIDAD JR, Manuel R.

STUDENT NO.:

2007103769

GROUP NO. 5

CHIEF PARTY:

DATE OF FIELD WORK: October 29, 2009

SUBMITTED TO:

PROFESSOR: Engr. B.A. Cervantes

GRADE

DATE OF SUBMISSION: November 05, 2009

GROUP NO. 5 Ramirez

CHIEF OF PARTY/LEADER: Julius Ceasar

MEMBERS: 1. Pascua, Jean Kathleen C.

OBJECTIVE: 1. To be able to lay a simple curve by using the tape alone. Instruments: 1. 2 range poles 2. chalk (for pavements) 3. 2 marking pins (for soft ground) 4. 50 meter tape

PROCEDURE: 1.

The professor gives the following data: I = ___________

R = __________

Station PC (preferably not on full station): ___________ Adopt Full chord length of _____ m 2. The professor assigns the location of PC in the field, together with the direction of the backward tangent. (Note: Be very careful in assigning the location of station PC and direction of the backward tangent so that the curve will not be obstructed by any large permanent structure.) 3.

The students:

3.1. Compute the central incremental angle of the simple curve assigned, Lc and Sta. Pt. 3. 2. Compute the incremental tangent offset distances x and y of each

intermediate stations before going to the filed. 3.3. Compute the first offset distances x and using the formula:

The tangent offset distance x1 must be solved using: The tangent offset distance y1 must be solved using: 3.4. Compute the second offset distances x and using the formula: The tangent offset distance x2 must be solved using: The tangent offset distance y2 must be solved using:

3.5.

Compute the succeeding offset distances x and y using the formula:

The tangent offset distance x3 must be solved using: The tangent offset distance y3 must be solved using: 3.6.

Compute the last offset distances x and y using the formula:

The tangent offset distance xn must be solved using: The tangent offset distance yn must be solved using: 3.7. Lay the curve in the filed starting in the position of the PC. The process explained below assumed that the total length of the tape will not be exhausted.

4. Station A is now laid on the ground using the procedure below. 4.1. The front tapeman should hold the 0 mark of the tape at station PC. 4.2. The tangent offset tapeman (man at station A’) should hold and locate the length x1 mark, loop the tape and hold also the next full meter length. 4.3. The point A tape man should locate and hold the y1 length of the tape from the tangent offset tapeman and also loop the tape and hold next full meter length of the tape. 4.4. The front tapeman and tangent offset tapeman should align themselves in the direction of the back tangent of the simple curve. 4.5. The three tapemen should stretch the tape and the point A tape man

should mark its exact position on the ground with a marking pin or a chalk if on pavement. 5.

Station B is now laid on the ground using the procedure below.

5.1. The front tapeman holds the 0 mark of the tape at station A. 5.2. The tangent offset tapeman (man at station B’) holds and locates the length x2 mark, loop the tape and hold also the next full meter length. 5.3. The point B tape man locates and holds the y2 length of the tape from the tangent offset tapeman; he also loops the tape and holds the next full meter length of the tape. The front tape man while holding the zero mark of the tape also holds the c tape length distance from point B tape man. 5.4. The front tapeman and tangent offset tapeman align themselves in the direction along the prolongation of line PC to A. 6. Station C and other full stations are now laid on the ground using the same procedures a to d. 7. Station PT is laid in the same manner as above but this time with a chord length of only c2. 8.

Determine the percentage of error by using the formula: