Civil Engineering Chapter 26 Homework The Length The Deadman Should Use Caution

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Exercise 26 Wall Anchoring 107

Exercise 26

Wall Anchoring

OBJECTIVE

The objective of this exercise is to execute anchoring

for landscape retaining walls using verticals (vertical

timbers), deadmen, and geogrid.

Follow manufacturer’s instructions when using

TEXTBOOK REFERENCE

Information related to this activity can be found in the

INTRODUCTION

Landscape retaining walls need to be anchored to improve

stability and counter the forces of gravity and soil/water

Vertical timbers are buried wood members placed

in an upright position directly in front of the joints of

stacked timber walls. Deadmen are horizontal timbers

placed behind staggered-joint timber walls. Deadmen are

anchored into the hillside to provide resistance to forces

pushing the wall forward. Geogrid is a fabric-like land-

scape material that is hooked or sandwiched between

Batter

To construct a wall with step-back (or stair-step) batter,

• Place the first course level.

• On each subsequent course slide the wall material

back from the front of the previous course. A

typical dimension for this setback would be

1 inch, but it may vary based on manufacturer

recommendations. Many segmental units have

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108 Exercise 26 Wall Anchoring

Vertical Timbers

To install vertical timber anchoring use the following

steps:

• Following completion of the second or third

course, auger 1 foot diameter holes in the ground

in front of the wall and centered on the joints

between timbers (Figure 26–2). The recommended

Deadmen

Deadmen should be installed every fourth vertical course

of a tie/timber wall. Measuring horizontally from the end

of the wall, install a deadman every 8 feet.

To construct deadman anchoring use the following

steps:

• Cut an opening in the appropriate course of the

A. First course is aligned

with planned wall location

Step–Back or Stair-Step Batter

Step

back

B. Subsequent courses are

placed back from front edge

of previous course

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Exercise 26 Wall Anchoring 109

• When placing the next wall course, connect it to

the deadman with a 12 inch nail.

• Backfill and compact over the deadmen when the

wall is complete.

Geogrid

Manufacturers or design professionals must calculate if

a wall requires anchoring with geogrid fabric. These cal-

culations should indicate the course in which the geogrid

• After compacting the backfill for the course

below the geogrid, roll the geogrid out flat behind

the wall along the entire length of the area to

be reinforced. The backfill area may have to

be widened to accommodate the width of the

geogrid.

Stacked

wall

Deadman spacing

Deadman extends

through to face of wall

Wall

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110 Exercise 26 Wall Anchoring

Lipped units may be set in place with the geogrid installed

between courses.

PREREQUISITE EXERCISES

Students should have successfully completed Exercise 5,

MATERIALS REQUIRED

• Proper clothing and safety gear

• Power auger (12 inch diameter) (prepared for

operation)

• Extended 3/8 inch auger bit

• 50 foot heavy-duty extension cord and access to a

• Square-nosed shovel

• Whisk broom

• Supply of wall materials, including ties/timbers

and segmental retaining wall units (including

EXERCISE DESCRIPTION

To complete this exercise, install the anchoring method

appropriate for each segment of wall. This exercise can be

combined with Exercises 22, 23, 24, and/or 25.

Figure 26–4 Geogrid placement.

Free-draining

angular fill

over wall pins

Wall material

Compacted

backfill

Compacted

backfill

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