Mapúa Institute of Technology

Muralla St., Intramuros, Manila.
School of Civil, Environmental, and Geological Engineering

Field Work No. 1
Laying of a Simple Curve by
Transit and Tape
(The Incremental Chord and Deflection Angle Method)

CE121F / B2

Submitted by:
Name: Patrick Emmanuel T. Gicale

Student No:

Group No: 1
Date of Performance:
Date of Submission:


The fieldwork was conducted at Intramuros Walls. Deflection angle method uses a transit and tape. tangent offset method uses a measuring tape only while double-deflection method uses a theodolite or transit only.” is to be able to lay a simple curve by deflection angle. curves are staked out by use of deflection angles turned at the point of curvature from the tangent to points along the curve. the sub-chords are provided at the beginning and end of the curve to adjust the actual length of the curve. Laying a simple curve can be done in several methods – by deflection angle method. We were given a radius and an azimuth where the point of curvature is to locate. we lay a simple curve using theodolite and tape by incremental chord and deflection angle method. Usually. In the deflection angle method. tangent offset method and double-deflection angle method. And then data needed in the fieldwork is calculated first before proceeding. The curve is set out by driving pegs at regular interval equal to the length of the normal chord. In this fieldwork. Bienvenido Cervantes Research and Discussion: The main objective of the first field work.Submitted to: Engr. The method assumes that there is no difference between . entitled “Laying of a Simple Curve by Transit and Tape.

the larger the degree of curve the “sharper” the curve and the shorter the radius. all the elements of the curve are inversely proportioned to the degree of curve. The radius and the degree of curve are not inversely proportional even though. . extending from one tangent to the next. as in the arc definition. This definition is primarily used by civilian engineers in highway construction.C. The chord definition is used primarily on railroads in civilian practice and for both roads and railroads by the military. the radius decreases. Conclusion: With this field work we were able to lay a simple curve by deflection angle and master the skill in leveling. As the degree of curve increases. A curve is said to be simple when it has the same radius throughout and consists of single arc of circle with two tangents meeting at actual point of intersection of roads. The underlying principle of this method is that the deflection angle to any point on the circular curve is measured by the one-half the angle subtended at the center of the circle by the arc from the P. when using the arc definition.length of the arcs and their corresponding chords of normal length or less. It should be noted that for a given intersecting angle or central angle. A simple curve is a circular arc. orienting and using the theodolite effectively. to that point.

Lastly. it is recommended that in measuring the chord make sure that the tape should not be long so that the correction in taping will be minimize. Final Data Sheet Data Given: Radius: 200m Backward Tangent Direction: N46E Forward Tangent Direction: S68E Station of the Vertex: 14+001 .It can be observed from the data gathered that the measured values are quite close to the actual length of the chord. the data acquired is accurate and reasonable. thus. make sure that you are always in line of sight with the theodolite. Recommendation: In order to minimize the error. it is recommended that you should follow all of the instructions written in the manual to commit less human errors and to save some time that will hinder the group to finish the experiment early. Also. There are several reasons that caused a discrepancy between the actual and experimental values for the long chord.

5 32’42’30’ ’ 65’50’47’ 32’55’23 65’25’ .88 2’32’ 1’16’ 20 8’15’ 4’7’30’’ 13’58’ 6’59’ 19’41’ 9’50’30’’ 25’24’ 12’42’ 31’7’ 15’33’30’ ’ 36’50’ 18’25’ 42’33’ 21’16’30’ ’ 48’16’ 24’8’ 53’59’ 26’54’30’ ’ 54’42’ 29’51’ 20 20 20 20 20 20 20 20 20 20 1.Station Occupi Observ ed ed PC 13+88 0 13+90 0 13+92 0 13+94 0 13+96 0 13+98 0 14+00 0 14+02 0 14+04 0 14+06 0 14+08 0 14+10 0 14+10 Increme ntal Chord Central Incremen tal Angle Deflectio n Angle from Back Tangent 8.

8556m Actual Length of the Chord: 218m .1.5 ’ 5’’ Computed length of the Chord: 217.