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Deep Foundations
Foundation Repair
Foundation Replacement
New Basements
Helical Piles
Drilled Piers
Resistive Piers
Liquefaction Solved
Wind Turbine Foundations
with Helical Piles
Solar Panel Arrays
with Ground Screws
Pipeline Anchors
Airport FAA Projects
Bridge Abutments
Post-tensioned Concrete
More Commercial Projects
Retaining Wall Basics
Retaining Wall Fortification
Solving Limited Access
Using EPS Blocks
Using W-beams
Drainage Systems
Excavation & Drilling
Grading
Road Washout Repair
Road Fortification
Hillside Stabilization
Challenging Hillside
Additions & Patios
Landslide Repair
Impact Walls
Avalon Supports
the Famous Rockettes
RETAINING WALL BASICS
Engineers can save owners money by using helical tiebacks for lateral support of retaining walls and foundations. Here a pair of retaining walls create a hillside terrace.

These retaining walls are held by helical tiebacks; the ends of the tiebacks protrude from the top faces of the red posts.

Soils Engineer:
Vicki Odello,
Haro-Kasunich & Associates

Structural Design Engineer:
Jody Collins,
Ifland Engineers
CASE STUDY #81 (1 of 2)

Avalon used helical tiebacks to laterally support a retaining wall of wide drilled piers on the edge of a sandy bluff.

CASE STUDY #81 (2 of 2)

Avalon installed 65-foot tiebacks into the bluff diagonally at approximately 25 degrees to support the retaining wall. Each of the 1.75 inch square-shaft helical tiebacks were tested to 73,000 lbs in tension.
Avalon builds retaining walls in difficult places, often inaccessible to large equipment.
CASE STUDY #05 (1 of 5)

The following five pictures concern the replacement of a collapsed retaining wall that had been supporting a creek-side home. The first photo shows the retaining wall which had fallen over.
CASE STUDY #05 (2 of 5)

With small equipment, Avalon installed vertical helical piers to support the new retaining wall, with helical tiebacks for lateral support.
CASE STUDY #05 (3 of 5)

Vertical and diagonal helix after preliminary concrete pour.
CASE STUDY #05 (4 of 5)

The tieback extensions are galvanized, epoxy coated, and taped for triple protection. Foam wrapping was installed to protect the tape from gravel backfill.
CASE STUDY #05 (5 of 5)

Completed wall with patio.
A retaining wall with helical tiebacks on a steep bluff.

Soils Engineer:
Tharp & Associates

Design Engineer:
Don Ifland,
Ifland Engineers
CASE STUDY #13 (1 of 2)

Limited access is rarely a problem for Avalon. This site precluded the use a tractor, and the steepness of the slope made the use of a portable drilling rig impractical. To make matters even worse, the soil was too weak to support a typical retaining wall.
CASE STUDY #13 (2 of 2)

The solution involved multiple steps. Avalon used vertical piers to support the weight of the wall and deck above, and pairs of helix tiebacks, one high and one low, to resist the lateral pressures of the hillside and house. In the photo below, the lower row of tiebacks are below grade.
Avalon installs retaining walls under existing houses.
Avalon Structural, Inc.
181 Ridgeview Drive
Aptos, CA 95003
(831) 479-4389 (office)
info@avalonstructural.com
Copyright © 2015
Avalon Structural, Inc.
All Rights Reserved
CA License 677116
Classifications:  B, C-8
Avalon is a general building
contracting firm and
does not employ engineers.