Building Official Determination 25-01: Helical Piles & Push Piers

Building Code Guides (BCGs) and Building Official Determinations (BODs) provide answers about the application of building codes and outline optional alternates. BODs are typically smaller in scope and address simpler questions. Code Guides provide a comprehensive alternative to a complicated set of code requirements.

BOD 25-01: Helical Piles & Push Piers

Geotechnical Reporting and Special Inspection Requirements

OSSC 1705.7, 1705.9, 1810.1.1, 1810.3.3.1.9

QUESTION:What are the geotechnical investigation reporting and special inspection requirements for the use of helical piles (aka helical anchors) and/or push piers as foundation support systems?

RESPONSE:A site-specific geotechnical investigation and report (geotechnical report) prepared by a Registered Design Professional licensed in the State of Oregon, as described in Sections 1810.1 and 1803 of the Oregon Structural Specialty Code (OSSC), is required for the installation of helical piles and push pier foundation systems supporting buildings that require a permit as described in Chapter 24.10 of Portland City Code, including buildings and structures subject to the Oregon Residential Specialty Code (ORSC) and the OSSC.

Continuous Special Inspections and reporting by an approved agency/special inspector are required for installation of push pier or helical pile products as described in OSSC Sections 1705.7, 1705.9 and 1704.2.4.

Exceptions: A site-specific geotechnical report and special inspections for installation of helical piles or push pier systems may be waived provided ALL of the following conditions are met:

1. The helical pile or push pier systems have a valid ICC-ES Evaluation report (or equivalent report acceptable to the Building Official or their designee) that waives the site-specific geotechnical reporting requirements and continuous special inspections.

2. The helical pile systems or push pier systems are being installed to support the type of structure specifically identified in the evaluation report.

3. The helical piles or push piers are not designed or required to resist lateral loads.

4. The helical piles or push piers are supporting a structure on a lot located entirely outside of a Title 33 Potential Landslide Area.  Title 33 Potential Landslide Areas are identified on www.portlandmaps.com under Public Safety and Hazards.

5. The helical piles or push piers are not being installed on sites with shifting soils, e.g. sites with known or suspected slope instability or other known or suspected geologic hazards.

6. The capacity of the helical pile system is established in accordance with the requirements of the corresponding evaluation report.

7. A design report stamped by a registered design professional is submitted at the time of permit application that specifies the minimum installation torque values required to achieve the geotechnical capacity for helical piles. The minimum design torque must be specified on the permit drawings.  For push piers, the permit drawings must specify the load testing requirements and acceptance criteria.

8. Periodic observations by the registered design professional or their designee shall be performed to verify helical pile and/or push pier systems are being installed per the design requirements.  A final summary report stamped by the registered design professional must be submitted to the building official or their designee prior to final inspection approval of the permit.  The report shall certify that the helical piles were installed in accordance with design and the minimum design torques specified.  Where push piers were installed, the load test values shall be reported verifying the geotechnical design capacity of the push piers.

DOWNLOAD a copy of this Building Official Determination:

Questions?  Free 15-Minute Appointments for Permit, Code, and Zoning Questions