Webinar instructions will be emailed before the date of the webinar.

Please log into the webinar 15 – 30 minutes before start time.

Log into Webinar
8:00 – 8:30 am MST
Morning Session
8:30 – 11:55 am MST
11:55 am – 12:25 pm MST
Afternoon Session
12:25 – 4:55 pm MST


Presented by
Bill Simpson, PE

Retaining Walls: What They Do and How They Do It
Defining “the wall”
Identifying forces on a retaining wall
How to account for and resist soil pressure
How water pressure impacts a retaining wall
The properties of the soil that contribute to the wall design
Equations and examples

Geosynthetics and Retaining Walls, Embankments and Slopes
Properties of common geosynthetics
How an MSE wall differs from other wall types
Discussion of different blocks, reinforcement, and their interaction
Design code requirements for an MSE wall
Geosynthetic properties for use in slope stabilization
Equations, calculations, and examples of internal stability of an MSE wall

Unreinforced Slope Stability Analysis
Fundamentals of slope instability
Soil and geological mechanics related to slope instability
How geologic conditions affect slope stability
Observations of slope instability
Construction practices to improve or restore slope stability
Equations, calculations and example of an unreinforced slope

Reinforced Slope Stability Analysis
Geosynthetic properties for use in slope stabilization
Deep seated stability analysis
Equations, calculations, and example of using geosynthetics to reinforce a slope
Soil properties and conditions that contribute to slope stability
Material required for the exposed face of the slope to maintain long term stability

Retaining Wall/Slope Lessons Learned
Preventing problems or failures of walls and slopes through improved site layout
Commonly overlooked design code requirements related to retaining wall layout and design
Roles and responsibilities of the design and construction team to ensure structure success
Typical causes of problems or structure failure
Recognizing and preventing a problem during construction
How water (both surface and below ground) affects an earth structure
What measures to take during construction to ensure long term earth structure success
Case histories and examples of failed structures


 Webinar Instructions

Each webinar session earns continuing education credit and can be registered for individually. All attendees must log-on through their own email – attendees may not watch together if they wish to earn continuing education credit. HalfMoon Education Inc. must be able to prove attendance if either the attendee or HalfMoon Education Inc. is audited.

Certificates of completion can be downloaded in PDF form upon passing a short quiz. A link to the quiz will be sent to each qualifying attendee immediately after the webinar. The certificate can be downloaded from the Results page of the quiz upon scoring 80% or higher.

Webinars are presented via GoToWebinar, an easy-to-use application that can be run on most systems and tablets. Instructions and login information will be provided in an email sent close to the date of the webinar. It is highly recommended that you download, install and test the application before the webinar begins by clicking on the link in the email.

GoToWebinar App requirements:
Windows 7 – 10 or Mac OSX Mavericks (10.9) – macOS Catalina (10.15)

Web Browser:
The two most recent version of the following browsers:
Google Chrome, Mozilla Firefox, Apple Safari, Microsoft Edge
Internet Explorer v11 (or later) with Flash enabled

Internet connection:
 Minimum of 1Mbps       Hardware: 2GB RAM or more

For more information, visit the Support section at


Professional Engineers
7.5 PDHs

7.5 HSW CE Hours

7.5 LU|HSW

Landscape Architects
7.5 HSW CE Hours

7.5 HSW PDHs

International Code Council
.75 CEUs (Sitework)


Continuing Education Credit Information
This webinar is open to the public and offers 7.5 PDHs to professional engineers, and 7.5 HSW continuing education hours to architects and landscape architects licensed in Montana. Courses and providers are not subject to preapproval in Montana.

Engineers, architects and landscape architects seeking continuing education credit in other states will be able to claim the hours earned at this webinar, in most cases. Refer to specific state rules to determine eligibility. No credit is offered to landscape architects in New Jersey.

The American Institute of Architects Continuing Education System has approved this course for 7.5 LU|HSW (Sponsor No. J885).  Only full participation is reportable to the AIA CES.

The Landscape Architecture Continuing Education System has approved this course for 7.5 HSW PDHs.  Only full participation is reportable to the LA CES.

The International Code Council has approved this event for .75 CEUs in the specialty area of Sitework (Preferred Provider No. 1232).

Completion certificates will be awarded to participants who complete this event, respond to prompts, and earn a passing score (80%) on the quiz that follows the presentation (multiple attempts allowed).


Bill Simpson, P.E.

Geotechnical Structure Design Specialist at Gradelta Engineering

Mr. Simpson founded Gradelta Engineering in 2020 with the intent to help clients better understand the combination of geotechnical and structural engineering that he has worked with for the past 20 years. He earned his B.S.C.E. and M.S.C.E. degrees from Georgia Institute of Technology. He currently provides engineering services to contractors and fellow engineers for earth structure pricing, along with the plans and calculations needed for construction. He frequently consults with clients regarding the optimal structure type and location on the construction site to minimize risk and maximize useable space. He also works in the education sector providing not just seminars such as this one, but also acting as a subject matter expert creating study guide and test prep content for the NCEES Professional Civil Engineer exam. Mr. Simpson has also worked with lawyers and insurance companies during forensic investigation and lawsuits surrounding retaining walls and slope failures. His hope is that through the instructional services that he currently provides, slopes will remain stable and retaining wall failure will be eliminated.

AIA Info

AIA Provider Statement:

HalfMoon Education Inc. is a registered provider of AIA-approved continuing education under Provider Number J885. All registered AIA/CES Providers must comply with the AIA Standards for Continuing Education Programs. Any questions or concerns about this provider of learning program may be sent to AIA/CES ( or (800) AIA 3837, Option 3).

This learning program is registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product.

AIA continuing education credit has been reviewed and approved by AIA/CES. Learners must complete the entire learning program to receive continuing education credit. AIA continuing education Learning Units earned upon completion of this course will be reported to AIA/CES for AIA members. Certificates of Completion for both AIA members and non-AIA members are available upon request.

Course Title: Retaining Wall Design and Global Stability Analysis: Rocky Mountain Region

Delivery Method: Live Online

Course Description: This course examines retaining wall function and principles, geosynthetics and retaining walls, embankments and slope, global/slope stability, and retaining wall failures and repairs.

Learning Objectives:

Learning Objective 1:
Learners will be able to explain how retaining walls work, and they will be able to identify and quantify the forces that act on retaining walls.

Learning Objective 2:
Learners will be able to differentiate between various types of retaining walls, and they will be able to identify types of geosynthetic materials and how they are used to enhance slope stability.

Learning Objective 3:
Learners will be able to identify types of deep seated slope failures, methods of slope stability analysis, slope stabilization techniques, and construction practices that improve or restore stability.

Learning Objective 4:
Learners will be able to describe how to prevent retaining wall problems or failures through proper site layout and wall design techniques, and they will be able to recognize potential retaining wall problems, causes, and repair strategies.

LUs: 7.5                                                                                              LU Type: LU|HSWs.

Prerequisites: Familiarity with earthwork

Advance Preparation: None

Program Level: Intermediate

Course Expiration Date: 01/03/2025

Complaint Resolution Policy:

Complaints regarding this course can be emailed to or by calling (715) 835-5900. A HalfMoon Education representative will respond within 72 hours to resolve the complaint, which will include, but not limited to, access to another CE activity at no or reduced cost or a full or partial refund. Each instance will be resolved on a case-by-case situation.