Modular Support Systems Technical Guide, Edition 2
2.0 Modular Support Technology
2.3 Information on Adjustability of MT Components
The MT System 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 inspection and maintenance requirements. It is not designed to be completely disassembled and then rebuilt or repurposed, 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.
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 pretensioning 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.
Twist-Lock( MT-TL) and Fast-Lock Connection Mechanisms
Prior to applying tension, repositioning the Twist-Lock and Fast-Lock can occur at any point along the MT open channel length. Final installation is achieved when the appropriate torque in the Instructions For Use( IFU) is applied to the bolt. Once the installation torque as defined in the IFU has been applied to the bolt, the location can no longer be adjusted. A new Twist-Lock must be utilized for final installation in a new location.
T-Head Bolt( MT-THB) Connection Mechanism
A Serrated T-head Bolt is fully adjustable along the serrated channel opening of the MT 90 H box profile. The bolt is not meant for installation in non-serrated open channel. The interlocking teeth are engaged immediately though the nut has to be properly installed to support published loads. It is not recommended to loosen and adjust the THB after applying tension.
Thread Forming Bolt( MT-TFB) Connection Mechanism
The MT-TFB forms a thread into the reinforced hole of the MT box profile( girder) during installation. 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). The MT-TFB can also be used to tap a thread more than a single time. Hilti recommends this be limited to no more than five occasions.
If a customer is uncertain how many times a reinforced hole in an MT closed profile( 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 upper limit of five uses for a single MT-TFB 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).
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