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TurnaSure rises to the challenge of new standards

AISC's larger bolt holes

In 2016 the American Institute of Steel Construction (AISC) approved the enlargement of 'standard bolt holes' in the forthcoming version of The Steel Construction Manual, AISC-360. Fabricators and Erectors of steel framing have since been permitted to use larger 'standard size' bolt holes for nominal sizes 1-inch and larger. The enlarged holes have an impact on structural bolting operations, and can negatively affect the use of traditional DTIs. The larger bolt holes may not fully support the DTI, leading to partial collapse into the bolt hole, and therefore not accurately indicate bolt tension.

TurnaSure's NEW Offset Extrusion DTIs meet this challenge head-on!

In order to address the challenge presented by AISC's new code, TurnaSure introduced an innovative design solution (US Patent #9,863,457) and a new method of manufacturing DTIs. Traditional DTIs are manufactured with the protrusions ('bumps') in alignment with the 'pockets' on the bottom side of the DTIs. The new process, which we refer to as "Offset Extrusion" allows the 'bumps' to remain where they must be to fit properly under bolt heads and heavy hex nuts, while offsetting the 'pockets' towards the OD of the DTI. This ensures they are safely away from the enlarged bolt hole, allowing the DTI to function predictably and accurately.

The Challenge - Traditional DTI Design

The traditional DTI design places the indentation directly beneath the protrusion. It is highly effective for tensioning today’s bolts but, with the new, expanded (AISC) bolt hole sizes, a traditional DTI could collapse into the void between the bolt and the steel.

The Solution - Our NEW Offset Extrusion DTI

The newly designed, patented Offset Extrusion DTI from TurnaSure shifts the indentations further out, leaving the protrusions perfectly placed in relation to the bolt head, but making ample allowances for the new bolt sizes while retaining the tensioning ability you know and trust!

TurnaSure Offset Extrusion DTIs are available in common inch-series structural sizes.

Contact TurnaSure today for more information, availability and quotes.