2.0 MODULAR SUPPORT TECHNOLOGY
Modular Support Systems Technical Guide, Edition 1
2.3 INFORMATION ON ADJUSTABILITY OF MT COMPONENTS
The MT System, as with all Hilti modular installation systems, is designed for a single permanent installation. A single permanent installation is achieved with the following: the assembly process is complete, the system is subjected to the final in-use conditions, and the expected design loads are applied to the structure. It may remain in this use for as long as the expected lifespan, with due adherence to projectspecific inspection and maintenance requirements. It is not designed to be completely disassembled and then rebuilt or re-purposed, as the use conditions of the original structure may have changed over time( e. g. applied loads, impact, corrosion attack, product modifications etc.). Any reuse of the MT System beyond a single permanent installation is at the risk of the customer.
Twist-Lock( MT-TL) Connection Mechanism
Thread Forming Bolt( MT-TFB) Connection Mechanism
The MT-TFB forms a thread into the reinforced hole of the MT girder during assembly. After assembly, the MT-TFB may be subsequently removed to enable positional adjustments of connectors. Once this thread has been formed, so long as the thread remains intact( e. g. it is not cross threaded), the threaded hole can be used up to four additional times( five in total). A torque-controlled wrench is recommended when reusing a reinforced MT girder hole. Reuse of the MT-TFB is possible but should be limited to five re-uses. Any reuse beyond this limit could lead to degradation of the tip of the bolt, thereby negatively impacting its performance.
If a customer is uncertain how many times a reinforced hole in an MT girder has been used, then a fresh hole should be used for installation. Likewise, a new MT-TFB should be used if it is unknown the number of times it has been used previously.
The Twist-Lock interface is designed for a single permanent installation. However, during assembly, the Twist-Lock may be repositioned as necessary until final installation is completed. Final installation is achieved when the Twist-Lock installation torque in the Instructions For Use( IFU) is reached.
Repositioning the Twist-Lock can occur at any point along the MT channel length. Once the installation torque as defined in the IFU has been applied to the Twist-Lock, its location can no longer be adjusted. A new Twist-Lock must be utilized for final installation in a new location.
The upper limit of five uses for a single MT-TFB for MT girder connections may be extended if the Hilti Adaptive Torque Module( SI-AT-A22, in combination with the Hilti impact wrench SIW 6AT-A22) is used with the correct MT-TFB parameter set( found via the QR code on the box of the MT-TFB’ s). An important feature of the Adaptive Torque Module is that it will indicate if the connection mechanism has been correctly set. If it determines the connection mechanism has been correctly set, a green light will illuminate, indicating the correct amount of pre-tensioning has been achieved. If a red light illuminates, then the connection mechanism is not sufficient and should not be used. Refer to the product documentation for the Adaptive Torque Module for additional guidance.
2023
19