UDOT

The written manual provides technical direction and expands upon and clarifies design and construction requirements as specified by AASHTO Specifications.


Geotechnical Manual of Instruction – October 2022
Revisions to the GMOI between published editions are issued through GMOI Policy Memoranda and are referred to as interim revisions. Requirements detailed in the memoranda are effective and enforceable on the effective date listed in the memorandum.

GMOI Written Manual Revision Log.
A copy of the GMOI Written Manual incorporating interim revisions is provided above for your convenience.

---

The previous version of the GMOI (September 2017) is available for your information below.
The September 2017 GMOI has been superseded by the October 2022 GMOI and revisions.

Geotechnical Manual of Instruction – September 2017

A document tracking the changes between the October 2022 GMOI and the September 2017 GMOI is provided for you below.

GMOI – September 2017 to October 2022 – Tracked Changes

Geotechnical Working Standards

Geotechnical Working standards (GWS) define the form, function and requirements of commonly used plan sheets. The geotechnical working standard identifies areas requiring geotechnical engineer input by a blue note. Update the geotechnical working standard where indicated by the blue notes. Ensure that the geotechnical working standard used is compatible with the design and details of a specific structure. The geotechnical working standard becomes part of the sealed plan set, and the Geotechnical Engineer of Record is responsible for all information on the geotechnical working standard. Review the geotechnical working standards, identify any areas of concern and inform the Structures Division of proposed changes to the geotechnical working standard beyond the changes indicated by the blue notes. The Geotechnical Design Manager must approve changes to a geotechnical working standard in areas not indicated by the blue notes.


Geotechnical Working Standards Revision Log

Geotechnical Working Standards (PDF format)

Geotechnical Working Standards (DGN format)

Geotechnical checklists provide guidance for field reconnaissance, subsurface exploration and geotechnical testing. However, checklists are not all inclusive, and geotechnical engineers must review the project documents and include all information required to reflect the designer’s intent.


Field Reconnaissance
Updated January 26, 2018

Geotechnical Subsurface Exploration
Updated January 26, 2018

Geotechnical Laboratory Testing
Updated January 26, 2018

A GMOI Revision Memorandum establishes interim revisions to GMOI policies, procedures, practices and technical requirements. The Structures Division issues memoranda as needed to ensure that the GMOI remains up to date and appropriately reflects changes in needs and requirements.


GMOI Revision Memoranda are associated with the GMOI version currently in publication. With the release of the 2022 GMOI, previous GMOI Revision Memoranda have been incorporated into the baseline manual. Previously released memoranda are available for review by following the link in the GMOI – September 2017 dropdown menu below.

Requirements detailed in the memoranda are effective and enforceable on the effective date listed in the memorandum and in the GMOI Revision Log.

Revision Title	Effective Date
Initial Publication of October 2022 Geotechnical Manual of Instruction
Structures Division Memorandum – GMOI October 2022	October 17, 2022
Revisions to the Written Manual
G17-W03 – Approved Retaining Wall Systems	April 02, 2021
Revisions to the Drawings
N/A
Revisions to the Checklists
N/A

Subscribe to the Department E-mail Notification List for Consultant Services to receive notice at time of distribution.

The September 2017 GMOI has been superseded by the October 2022 GMOI. The information provided by the September 2017 GMOI and its associated memoranda is provided by the link below.


September 2017 GMOI and Associated Memoranda

The GMOI provides a field work form for use in projects to obtain and document permission to access private property. In order to view and print the form correctly and ensure use of the latest form, download the form before each use.

Form	Purpose
Exploratory Drilling Permit to Enter Updated January 26, 2018	To obtain and document permission to access private property directly from the property owner.

Template	Purpose
Simplified SPT Performance-Based Assessment of Liquefaction and Effects method (SPLIQ)	If a site specific Newmark Analysis is not performed, compute and compare deformations estimated using at least two of the methods defined in Appendix A11 of the AASHTO LRFD Bridge Design Specifications. Compare the results to those obtained using the SPLIQ.
SPLIQ Users Manual
Method for Determining Surcharge Fills Considering Post-Construction Secondary Compression	Used to compute surcharge in the absence of project specific laboratory test data of secondary consolidation settlement parameters for surcharged soils.
Construction Settlement Spreadsheet	Used for independent evaluation of the projected construction settlement.