Curve (Surveying)
Curve (Surveying)
SIMPLE CURVES
     •   The simple curve is an arc of a circle.                    SIMPLE CURVE                                               ELEMENTS OF A SIMPLE CURVE
     •   It is the most commonly used.
                                                                                                                        E       External Distance       Degree of Curve
     •   The radius of the circle determines the
         “sharpness” or “flatness” of the curve.                                                                        T       Tangent Distance        Arc Basis
                                                                                                                                                                20 = 𝑅𝐷
     •   The larger the radius, the “flatter” the curve.
                                                                                                                        m       Middle Ordinate
                                                                                                                        L       Long Chord
ELEMENTS OF A SIMPLE CURVE                                                                                              Lc      Length of Curve
SIMPLE CURVES
A 3° curve has an angle of intersection of 24°, what    A simple curve with tangents AV and VE have                A simple curve the azarailgents that intersect at an
is the length of the long chord and the length of the   azimuth of 260°48’ and 285°40’ respectively. Point B       angle of 30°. A point P on the curve has a chord
curve?                                                  is taken along AV and C along VE. The azimuth and          length of 42.8 m from the PT and the deflection angle
                                                        distance of BC are 272°16’ and 61.22 m respectively.       from the forward tangent to the same point is 4°20’.
                                                        The degree of curve is 5°. If stationing of point B is 8   Determine the middle ordinate.
                                                        + 126.3, determine the stationing of PT.
SIMPLE CURVE
The deflection angles of two intermediate points A       Two tangents having an azimuth of 265° and 289°
and B of a highway curve are 5°15’ and 10°15’            respectively intersect at station 10 + 195.35 and are
respectively. The chord distance between points A        to be connected with a 5° simple curve. Without
and B is 20 m, while the long chord is 150 m.            changing the direction of the tangent, it is required to
Stationing of PI is 8 + 060. Find the stationing of PC   find the radius and the station of the PC of the new
and PT                                                   curve such that the new PT is 5 m directly opposite
                                                         but outside the old PT.
SIMPLE CURVE
A 7° circular turnout is to connect a railway track,
loading due east to the mouth of the tunnel which is
70 m from station 7 + 812 as shown on the figure.
Use chord basis
SIMPLE CURVE
Piers of the proposed overpass in Nagtahan are to be placed with clearance of
2.5 m of the existing Ramon Magsaysaty Avenue as shown
a. Determine the minimum distance between the piers when the radius of the
curve is 100m width of the roadway is 20m.
COMPOUND CURVE
A compound curve consists of two (or more) circular curves between two main                                ELEMENTS OF A COMPOUND CURVE
tangents joined at point of compound curve (PCC). Curve at PC is designated as 1
(R1, L1, T1, etc) and curve at PT is designated as 2 (R2, L2 , T2 , etc).                                   PC          point of curvature              I          angle of intersection = I1 +
                                                                                                                                                                        I2
                                                                                                            PT          point of curvature              I1         central angle of the first
                                                                                                                                                                        curve
                                                                                                            PI          point of intersection           I2         central angle of the second
                                                                                                                                                                        curve
                                                                                                            PCC         point of compound curve         L            length of long chord from
                                                                                                                                                                      PC to PT
                                                                                                                                                        LC1         length of first curve
                                                                                                            T1         length of tangent of the first   LC2         length of second curve
                                                                                                                        curve
                                                                                                            T2         length of tangent of the         L1         length of first chord
                                                                                                                        second curve
                                                                                                            T1 + T2 = length got7of common              L2         length of second chord
                                                                                                                            tangent measured from
                                                                                                                            V1 to V2
COMPOUND CURVE
1. A long chord from PC to PT of a compound curve      2. A village in Mindoro is to be protected by a          3. A compound curve laid on their tangents has the
is 180 m long and the angle it makes with the longer   floodwall and should start at station 20 + 304 forming   following data shown below. Without changing the
and shorter tangents are 12° and 18° respectively.     two consecutive simple curves ending at Sta 20 +         direction of the two tangents, it is required to change
Find the difference in radius of the compound curve                                                             this compound with a simple curve that shall end at
                                                       544. At point V on the opposite bank of the river, the
if the common tangent will be parallel to the long                                                              the same point. Find the radius of the new curve and
chord                                                  azimuth of lines tangent to the PC and PT were taken     stationing of PC if PI1 is at 6 + 425.82. I1 = 22°, D1
                                                       to be 60° and 295° respectively. The degree of the       = 3°, I2 = 36°, D2 = 5°
                                                       first curve is 4° and that of the second curve is 5°.
                                                       Compute the stationing of PCC.
REVERSE CURVE
A reverse curve consists of two                                                                               Reversed Curve for Nonparallel Tangents
simple curves joined together but                                                                             The following figure is an example reversed curves of unequal radii connecting non-
curving in opposite directions.                                                                               parallel tangents.
The instant change in direction at
the point of reversed curvature
(PRC) brought some safety
problems. Despite this fact,
reversed curves are being used
with great success on park roads,
formal paths, waterway channels,
and the like.
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REVERSE CURVES
The perpendicular distance between parallel tangents    The common tangent BC of a reverse curve is 280.5        A reverse curve connects two converging tangents
of the reverse curve is 35 m. The back tangent has an   m and has a bearing of S 47°31’ E. AB is the tangent     that intersect at an angle of 30°. The distance of this
azimuth of 270° while the common tangent is 300°. If    of the first curve whose bearing is N 72° 45’ E. CD is   intersection from the PI of the second curve is 150 m.
the radius of the first curve is 160 m, determine the   the tangent of the second curve whose aziming is N       The deflection angle of the common tangent from the
radius of the 2nd curve.                                38° 13’ E. A is at the PC while D is at the PT. The      back tangent is 20° and the degree of curve of the 2nd
                                                        radius of the first curve is 180 m and its PI is at      curve is 6°. Find the degree of the first curve
                                                        station 12 + 523.37. Find the stationing of PT.
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     𝟏                          𝟏                                       𝒈𝟏 𝑳
𝒂 = 𝒈𝟏 𝑳                  𝒉𝟏 = 𝒈𝟏 𝑺𝟏                          𝑺𝟏 =
     𝟐                          𝟐                                      𝒈𝟏 −𝒈𝟐
     𝟏                          𝟏                                       𝒈𝟐 𝑳
𝒃 = 𝒈𝟐 𝑳                  𝒉𝟐 = 𝒈𝟐 𝑺𝟐                          𝑺𝟐 =
     𝟐                          𝟐                                      𝒈𝟐 −𝒈𝟏
                                                                                                                                                                                                   12
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     𝑳𝟏 𝑳𝟐 |(𝒈𝟏 −𝒈𝟐 )|           𝒈𝟏 𝑳𝟐
                                     𝟏             𝒈𝟐 𝑳𝟐
                                                       𝟐
𝑯=                        𝒔𝟏 =              𝒔𝟐 =
        𝟐(𝑳𝟏 +𝑳𝟐 )                𝟐𝑯                𝟐𝑯
𝒚    𝑯
   =
𝒙 𝟐 𝑳𝟐
     𝟐
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EARTHWORKS
Earthworks surveying is important especially in large-scale projects such as                                   EXCAVATION
residential development, roads, railways and other government infrastructure.
                                                                                                               Excavation is the loosening of the soil from its natural, in situ, stage.
Earthworks usually involve either the removal or placement of soil or land mass on a
particular area.                                                                                                   •    Levelling          This word is used to describe a situation where only a
                                                                                                                        levelling of bumps and depressions is necessary to provide a sufficient
    •    For this purpose, surveyors calculate the volumes of cuts and embankment                                       width for the road at a uniform level.
         fills                                                                                                     •    Cut to crossfill means that the soil is excavated (cut) from one side of the
                                                                                                                        road and used as fill material at the other.
The principal activities in earthworks are:                                                                        •    The U-cut is a cut which is roughly shaped as a U.
                                                                                                                   •    Suitable soil has to be "borrowed" from outside when the excavated soil
    •    measuring and calculation of volumes
                                                                                                                        within the road width is not sufficient for a fill or embankment
    •    excavation which includes levelling, cut to crossfill, U-cut and borrow
         excavation
    •    loading, hauling and unloading
    •    filling, including spreading and compaction
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EARTHWORKS
                                                                                                                MEASURING AREAS AND VOLUMES
Hauling is the transport of soil, the modes of haulage vary with the distance.
Unloading is usually done by tipping. Tipping vehicles can also spread the
soil/gravel.
                                                                                                                                            𝒘             𝑪
                                                                                                                                       𝑨=     (𝒉𝑳 + 𝒉𝑹 ) + (𝒅𝑳 + 𝒅𝑹 )
                                                                                                                                            𝟒             𝟐
                                                                                                                                                               𝑳
                                                                                                                Volume by End Area                      𝑽𝒆 = (𝑨𝟏 + 𝑨𝟐 )
                                                                                                                                                               𝟐
                                                                                                                                                               𝑳
                                                                                                                Volume by Prismoidal                    𝑽𝑷 = (𝑨𝟏 + 𝟒𝑨𝒎 + 𝑨𝟐 )
                                                                                                                                                               𝟔
                                                                                                                                                                𝑳
                                                                                                                                                        𝑪𝒑 =      (𝑽 − 𝑽𝟐 )(𝑯𝟏 − 𝑯𝟐 )
                                                                                                                                                               𝟏𝟐 𝟏
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EARTHWORKS
The cross section notes shown below are for ground                                                              A 60 x 60 square lot is to be divided into 9 square
excavation for a 10 m road.                                                                                     sections. Determine the volume of earthworks
                                                                                                                excavated if the ground surface is to be leveled to
         Station 25 +100                     Station                                                            elevation 10 m. The following data are the elevations
                     25 + 150                                                                                   of the ground surface
What is the volume of excavation between the two AIV = 11.8 BIV = 13.8 CIV = 11.9 DIV = 13.9
stations using
a) Volume by end area method
b) Volume by prismoidal formula
c) Volume by prismodial correction (assume 2:1)
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