What is turn of the nut method?
The Turn-of-Nut method is widely used to obtain the minimum preload tension force specified for bolts in slip-critical connections. This method consists in first snug-tightening the bolts.
What are the acceptable bolting methods per AISC?
There are four acceptable installation methods to obtain the pretension values for bolting: turn-of-nut method (with or without match marking), calibrated wrench method, twist-off-type tension-control bolt method and direct tension indicator method. Each of these methods is assumed to be used independent of the others.
How do tension indicating bolts work?
Direct Tension Indicators work when the patented protrusions are compressed as the axial tension force in a bolt or stud is increased by rotating a nut. Due to the protrusions, the bolt achieves proper tensioning while still leaving a small gap between the bolt head and the surface of the DTI.
What is snug tightening?
Snug-tight is the condition that exists when all of the plies in a connection have been pulled into firm contact by the bolts in the joint and all of the bolts in the joint have been tightened sufficiently to prevent the removal of the nuts without the use of a wrench.
What is ASTM F3125?
ASTM F3125 is a standard material specification covering chemical, physical and mechanical requirements for quenched and tempered bolts manufactured from steel and alloy steel in inch dimensions, in two strength grades, two types and two styles.
What is finger tight torque?
(of a screwed connection) tightened using the fingers, and no tools, to a torque of about 15 to 20 inlb or 1.7 to 2.3 Nm.
What section of the RCSC specification covers direct-tension indicators?
Direct-tension-indicator pre-tensioning is covered in Section 8.2.4 of the RCSC Specification. Strict adherence to the manufacturer’s installation instructions is required with direct-tension indicators (DTI). 6.6.8. What is the upper limit on the installed tension of high-strength bolts?
What is the RCSC F959 direct tension indicator?
DTIs within the RCSC Specification section 8.2.4 are described thus: “ASTM F959 direct tension indicators are recognized in this Specification as a bolt-tension-indicating device.
What is a tension indicator?
capable of indicating the achievement of a specified minimum bolt tension in a structural bolt and are intended for installation under either a bolt head or a hardened washer. Steel materials used in the manufacture of direct tension indicators shall be designed, processed, heat treated, and protectively coated as specified.
What is the RCSC specification for twist-off tension control?
The 2004 RCSC Specification covers the use of twist-off-type tension-control (TC) pre-tensioning in Section 8.2.3. It should be noted that the sheared-off splined end of an individual bolt indicates only that, at the time the splined end was broken, enough torque had been applied to the bolt to fracture the break-neck.