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AC358 Revisions are Approved by ICC-ES
by Moncef Souissi, CTL / Thompson, and
Darin Willis, Ram Jack Systems Distribution
June 7, 2012
After two long years of hard work and countless conference calls and meetings, the revised Acceptance Criteria for Helical Pile Systems and Devices (AC358) has finally been approved by the International Code Council (ICC). This is a very important milestone for our industry as helical piles are now recognized as acceptable piles per IBC 2012 and 2009 in addition to 2006. Design engineers will be able to confidently specify helical piles that have an ICC-ES ESR report knowing these piles have passed the rigorous testing and quality control requirements defined in AC358.
The following is an abbreviated list of some of the more significant changes from the previously approved AC version from June 2007.
Name Change – from Helical Foundation Systems and Devices to Helical Pile Systems and Devices
IBC Compliance – now conforms to IBC 2012, 2009 and 2006
ASTM Axial Compressive Load Test – D1143-07e1 – formerly 1143-81(1994)e1
ASTM Axial Tensile Load Test – D3689-07 – formerly D3589
Coupling Rigidity Testing (for manufacturers) – side by side tests shall be conducted on specimens with and without coupler(s). The location of the coupler(s) on the shaft shall be selected to represent field installation and create the largest expected lateral deformation.
Torsion Test on Combined Shaft (with Coupling) and Helix Plate (for manufacturers) - In addition to specimens prescribed in Section 184.108.40.206, a minimum of three specimens for each helix configuration (variation in diameter, thickness, steel grade, pitch, and edge geometry) shall be tested.
Pile Torsional Test Requirements (for manufacturers) - The maximum installation torque capacity of the helix shall be considered acceptable provided it exceeds the maximum installation torque capacity of the shaft.
Pile Testing (for manufacturers) - For each test site, geotechnical investigations shall be conducted in accordance with IBC Section 1803.2 and reported in accordance with IBC Section 1803.6.
Group Effect (for engineers and installation contractors) – pile spacing shall be 3D from the tip of the largest helix bearing plate or 4D from center to center of the shafts
Conformance Dates (for existing ESR report holders) – the two existing ESR report holders (Ram Jack Systems and MacLean-Dixie HFS) have until December 1, 2013 to successfully complete the testing requirements defined in the acceptance criteria in order to maintain their product(s) ESR Reports.