Civil Engineering Chapter 8 Homework Another Consideration For Project Layout Whether

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Exercise 8

Construction Staking

OBJECTIVE

The objective of this exercise is to demonstrate staking

and measurement techniques used to lay out projects.

TEXTBOOK REFERENCE

INTRODUCTION

Identifying the location of proposed improvements on

a site is necessary when constructing any landscape

project. Accurate layout of the elements of a landscape

design requires mastery of the techniques and methods

of construction staking. Techniques for construction

Staking Techniques

Following are step-by-step descriptions of the techniques

that can be used to accurately locate points and lines

Locating Points Using Triangulation

• Identify two known points in a landscape that

are within a short distance of the object being

located.

• Measure from each point to the object being

located (Figure 8–1A).

adjust for scale. Where the arcs intersect is the

location of the unknown point (Figure 8–1B).

This process can be reversed for locating an

object in the field.

Layout of Right Angles Using 3, 4, 5 Triangle

• Locate an existing straight edge at the

project site.

• Adjust both tapes until the 4 foot mark on tape

A and the 5 foot mark on tape B intersect. Mark

directly below that point (point C, Figure 8–2).

• The line traveling from point A and passing through

point C will be at a right angle to the first edge.

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• From points B and C, stretch tape measures (tapes

A and B in Figure 8–3) in the direction of the

desired perpendicular.

• Select a measurement on tape A and match it with

the same measurement on tape B.

• Mark the point where these like measurements

intersect (point D, Figure 8–3).

• A line laid out from point A through point D will

be at a right angle to the baseline.

38 Exercise 8 Construction Staking

A. Measure the distance to unknown point from known Points A and B.

B. Draw arcs for both distance A and B. Unknown point is where arcs intersect.

Known

point B

Unknown

point C

20′

Figure 8–1 Locating objects using triangulation.

Check diagonals

for equal length

Tape A

Tape B

Existing

straight

90°

lineMeasurement

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• If one measurement is longer than the other,

the long corner must be pushed in slightly and

the short corner pulled out slightly until the

measurements match.

Locating Radius Points and Marking Curves

• Locate the point where the curve is to

begin along a baseline at the site (tangent)

(Figure 8–5A). Identify the general location

of the radius point of the curve.

• Extend a tape measure from the baseline point in

• Extend a tape measure from the radius point in the

direction of the endpoint. The tape should pass

through the angle point.

• Adjust the tape so it is the exact length of the

radius of the curve. The point where the tape ends

is the precise location of the endpoint. Mark this

point with a stake.

• Anchor the tape measure at the radius point

with a screwdriver and pull the tape taut

(Figure 8–5C). Swing the tape from the

beginning point of the curve to the curve’s

Exercise 8 Construction Staking 39

Ending point

New curve would

begin at ending point

Radius

point

Curve

Anchor tape

measure at

radius point

with screwdriver

New tangent

at right angle

to 2nd line

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Layout of Arcs using Radii and Chords. For designs

with complex curvilinear layout, the curved element

can be located easily if the design professional has pro-

vided the radius and the chord for each segment of the

curve.

point (Figure 8–5C).

• Set up a second measuring tape anchored to the

beginning point of the curve.

• Extend the second tape the length of the chord

length of the chord. The intersection point is the

ending point of the curve.

• Mark the curve from its ending point back to its

beginning point using the radius measuring tape

(Figure 8-5C).

Construction Staking Methods

The techniques described earlier can be used to locate

individual components of a design, but a consistent

method needs to be employed when an entire design

needs to be staked. Several methods are available for

project layout, but three methods are most often used:

grid layout, baseline layout, and object dimensioning.

Selection of a layout method may be determined by

construction documents prepared for a project. If a set

of plans indicates location of elements using a particular

and contractors should not undertake a project that is

beyond their abilities.

The following paragraphs describe steps to measure

and lay out projects using grid layout, baseline layout,

and object dimensioning. To use each of these layout

methods a scaled, measurable plan of the project design

To create grid layout measurements for a project use

the following steps:

• On the plan draw two perpendicular baselines.

walls, or through an open area where a tape

measure can be placed to act as a temporary

baseline.

• Label one of the baselines X and the other

called the X measurement.

• Repeat this process for the Y guideline.

• You should now have X and Y measurements for

the point you selected.

• Repeat those steps until each point to be located

has an X and Y measurement.

To locate grid measurements on a project site use the

following steps:

• Identify the starting point, the X baseline, and

40 Exercise 8 Construction Staking

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line should intersect with the line created in the

previous step.

• The intersection of the two lines is the location of

the point you are trying to locate.

• Repeat this process for all points that require

locating.

Baseline Layout. Baseline layout is similar to the grid

layout method but uses only one baseline for making

measurements and placing stakes rather than two. It is

useful for sites where only one clear baseline can be iden-

tified or established or for sites that are long and narrow.

To create baseline layout measurements for a project,

use the following steps:

• Draw one baseline on the plan. The baseline

should be in a location that can be easily laid out

on the site. Mark one end of the baseline as the

beginning point.

• Select a point on the design to be measured.

• Draw a guideline at a right angle to the baseline

that passes through the selected point.

• Measure along the baseline from the beginning

point to the guideline. This measurement will be

Exercise 8 Construction Staking 41

A. Grid layout

Beginning point

Baseline X

Baseline Y

Object being

located

Existing

building

4,12,1

4,42,4

B. Baseline layout

Beginning point

Baseline

Object being

located

Existing

building

2′ 4′

5′

Figure 8–6 Construction staking methods.

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To locate baseline measurements on a project site, use

the following steps:

• Identify the beginning point and the baseline on

the project site. Stretch a tape measure along the

baseline.

correct location of the point you are trying to locate.

• Repeat this process for all points that require locating.

Object Dimensioning. Object dimensioning is used

when the location of improvements can be measured off

existing landmarks such as structures (Figure 8–6C).

To create object dimensioning measurements for a

project use the following steps:

the measurement or align the measurement with a

second existing object.

• The existing object, or the measurement point of

the first object located, is then used to continue

measuring other points for the project.

To locate object dimensions on a project site, use the

following steps:

• Identify the existing object used to establish

other points.

Staking Offsets

Stakes and original markings are often disturbed during

the construction process. To avoid the process of restak–

ing a site, use offsets. To do so, use the following steps:

• Stake out the construction points of a project.

depending upon project conditions. So long as the

offset is consistent for every stake within a set of

points, it makes little difference what the distance

or direction is.

DISCUSSION

PREREQUISITE EXERCISES

Students should have successfully completed Exercise 1,

Construction Math, and Exercise 3, Measuring with Archi-

tects’ and Engineers’ Scales, before beginning this exercise.

MATERIALS REQUIRED

EXERCISE DESCRIPTION—PART A

To complete this exercise use the techniques described

previously to lay out each of the objects shown in

Figures 8–7 and 8–8. The drawings are to scale and must

be measured before staking.

42 Exercise 8 Construction Staking

B A

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Exercise 8 Construction Staking 43

10′-0″

5′-0″

Radius

EXERCISE DESCRIPTION—PART B

To complete this exercise install construction staking for

the project identified in Figure 8–9 first using grid layout

and then with baseline layout.

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