Application Specifications

Suggested Simplified Building Specification - choose one item within (brackets)

All bolts shall be installed using Direct Tension Indicators (Standard style or Squirter® style) made to ASTM F959 latest revision. DTI's shall be installed and inspected on the bolts per the manufacturer's instructions, or to the provisions contained in the Research Council on Structural Connections "Specification for Structural Joints Using A325 and A490 Bolts". Note: Completely compressed DTIs showing no visible remaining gap are acceptable. DTIs washers must be placed directly against the steelwork over standard sized holes with the bumps facing away from the steelwork.

DTI's shall be (choose one):

Standard DTI's made to be inspected with a feeler gage.

"Self-indicating" or Squirter® style DTIs made with silicone embedded in them, inspected by means of the visual ejection of silicone as the DTI protrusions compress. Squirter® DTI's must be calibrated per manufacturer's instructions prior to use.

If it is necessary to install (Standard) DTI washers on oversized or short slotted holes, particular attention must be paid to the position and selection of hardened flat washers. See DTI manufacturer's instructions and the Research Council on Structural Connections "Specifications for Structural Joints Using A325 and A490 Bolts".

If it is necessary to install (Squirter® style) DTI washers on oversized or short slotted holes, special dimension flat washers must be used under the Squirter® DTI washer against the steelwork. See flat-washer-chart.html for particular advice on size, specification, thickness, and dimensions of these flat washers. Any special flat washers needed are available for nominal cost from Applied Bolting Technology Products. Click here for more information on using Squirter® DTIs with oversized or short slotted holes. Click here for how to inspect squirter® DTIs.

Suggested Simplified Bridge Specification - choose one item within (brackets)

All bolts shall be installed with Direct Tension Indicators (Standard style or Squirter® style) made to ASTM F959 latest revision. Installation and inspection shall be according to the DTI manufacturer's instructions using a .005" (0.13 mm) feeler gage. DTI's may be located either on the nut end or under the bolt head as required.

Type 3 (weathering steel) DTIs when installed to .005" residual gap may have to be installed only on the nut end. See advisory.