TNA 144ksi Bolts

For application using the Torque + Angle Installation Method. This revolutionary structural bolt grade is designed to allow for a single bolt grade to be used in all connection types.

144 is the strength in ksi for ASTM F3148 Fixed Spline TNA® Bolts. This is the first significant addition to structural bolt grades since A490 was introduced.

Development of the TNA® bolt is borne out of years of research and development. The bolt takes advantage of existing raw material consistency and modern manufacturing techniques allowing production of a high strength bolt with A490 equivalent tensions while utilizing cost effective raw material used to manufacture A325. The design allows for single sided installation in all connection types with definable tensions for both the snug and final condition. TNA® bolts offer the best ROI by reducing total installed costs as much as 50%.
The steel construction market has been clamoring for a single bolt grade for years. LeJeune Bolt took the initiative to bring it to market. The contribution of a standardized single bolt grade to overall steel construction efficiency will be significant in the battle with concrete. Modern developments in construction like 3D modeling, BIM and design-build delivery systems have pushed contractors, fabricators and erectors to produce more with less time. TNA® Torque + Angle Fastening System and the 144ksi grade bolt will play a pivotal roll in reducing fabrication and erection times, thereby helping to reduce overall steel construction timelines and cost.

The TNA® bolt design resembles a traditional twist-off type bolt but is different in many ways. TNA® bolts are head marked according to ASTM F3148 requiring 144 to be stamped signifying the bolt grade. LeJeune Bolt also marks every bolt with TNA®. Head marking is industry protocol to identify any structural bolt grade and type.

The fixed spline can be confusing, perhaps even mistaken for a twist-off type bolt. There are a few design differences at the spline end that differentiate TNA® bolts from twist-off type bolts. The TNA® bolt has no shear groove between the spline and threaded portion of the bolt. The shear grove is where the tip is designed to come off the twist-off type bolt. The spline is also significantly larger in area compared to the spline of like diameter twist-off type bolts. This distinction will prevent a shear wrench used to install twist-off type bolts from being used on a TNA® bolt.

ASTM F3148-17a Standard Specification for High Strength Structural Bolt Assemblies, Steel and Alloy Steel, Heat Treated, 144ksi Minimum Tensile Strength, Inch Dimensions.

Within the standard you will find all of the information required to specify TNA®.  Included in the standard you will also find important additional information needed to implement the system.  In F3148 you will find Annex A1. Rotational Capacity (RC) Tests, Appendixes X1. Test and Installation Procedures for Torque-and-Angle Tensioning of Fixed Spline F3148 Assemblies, X2. Pre-Installation Verification Testing and X3. Installation Procedure.  In these Appendixes are the required Pre-Installation Verification Testing Procedure and the formal Installation Procedure.  This information is typically found in RCSC ” Specification for Structural Joints Using High-Strength Bolts”.  During the interim period prior to publication by RCSC these procedures will be referenced in this ASTM document.  When the Torque-and-Angle installation method can be included in the RCSC publication, it will be balloted for removal from the ASTM document.  This form of reference has precedence from other bolting innovations following the same acceptance path.

To obtain your own copy of F3148 you can go to www.astm.org.  For subscribers, the new standard can be downloaded as part of your subscription service.  If you’re not a subscriber, download your own copy from the ASTM site or contact LeJeune Bolt and we will provide a serialized copy free of charge.

ASTM F3148 Fixed Spline Bolt Assemblies

Every TNA® Bolt is sold as a matched assembly including bolt, nut, and washer. Each unique matched assembly is certified as a set. TNA® assemblies are available as Type 1, Type 1 Mechanically Galvanized, Type 3 and Type 3 Mechanically Galvanized. Available diameters are 5/8”, 3/4”. 7/8”, 1”, 1 1/8”.

TYPE 1 PLAIN

SIZES

TYPE 1 MG

SIZES

TYPE 3 PLAIN

SIZES

TYPE 3 MG

SIZES

Reference

Torque + Angle Installation Method

  1. Set the tool to the Snug Mode and engage the first bolt in your connection.
  2. Pull and hold the trigger until the tool shuts off.
  3. If the cycle was completed successfully the Cycle Indicator Light will show solid green.
  4. Repeat the process for each bolt in the connection.

For larger connections, a second snug pass can be performed to ensure all plies are in firm contact and that all the bolts are snug to the same value. For connections only requiring a snug condition your work is done. For Pre-Tensioned or Slip-Critical Connections, proceed to Step 2.

After the Snug Tightening step is completed:

  1. Switch the tool to the Angle Mode
  2. Set the Angle Control Dial to the degree of rotation specified for your bolt length in ASTM F3148 (It’s 90º or 120º)
  3. Engage the first bolt in the pattern that you established during the snug mode. Pull and hold the trigger until the tool shuts off.
  4. If the cycle was completed successfully the Cycle Indicator Light will show solid green.
  5. Repeat the process for each bolt in the connection.

Your bolts are now installed to a consistently reliable tension well above the specified minimum.

Inspection after Snug Tightening

  1. Perform routine observation of the snug tightening process to verify proper techniques are followed as described in Step 1: Snug Tightening
  2. Verify that the plies in the connection are in firm contact.
  3. Verify that the proper bolt length was used. The face of the nut shall be at least flush with the first thread of the bolt and there should be no more than 3 threads stick-out beyond the face of the nut to prevent thread runout.

Inspection after Angle Tightening

  1. Perform routine observation of the final angle tightening process to verify proper techniques are followed as described in Step 2: Angle Tightening

NOTE: If routine observation is not possible, match marking for final installation may be required during the angle tightening process. This step of visual inspection should be included in the scope of work or contract documents to avoid disputes.

ASTM F3148-17a Standard Specification for High Strength Structural Bolt Assemblies, Steel and Alloy Steel, Heat Treated, 144ksi Minimum Tensile Strength, Inch Dimensions.

Within the standard you will find all of the information required to specify TNA®.  Included in the standard you will also find important additional information needed to implement the system.  In F3148 you will find Annex A1. Rotational Capacity (RC) Tests, Appendixes X1. Test and Installation Procedures for Torque-and-Angle Tensioning of Fixed Spline F3148 Assemblies, X2. Pre-Installation Verification Testing and X3. Installation Procedure.  In these Appendixes are the required Pre-Installation Verification Testing Procedure and the formal Installation Procedure.  This information is typically found in RCSC ” Specification for Structural Joints Using High-Strength Bolts”.  During the interim period prior to publication by RCSC these procedures will be referenced in this ASTM document.  When the Torque-and-Angle installation method can be included in the RCSC publication, it will be balloted for removal from the ASTM document.  This form of reference has precedence from other bolting innovations following the same acceptance path.

To obtain your own copy of F3148 you can go to www.astm.org.  For subscribers, the new standard can be downloaded as part of your subscription service.  If you’re not a subscriber, download your own copy from the ASTM site or contact LeJeune Bolt and we will provide a serialized copy free of charge.