What is a snug tight bolt?

What is a snug tight bolt?

Snug Tight Bolt Installation Snug tight condition is defined as the full effort of a typical person as applied using an ordinary spud wrench (Figure 10). A bolt in snug tight condition will carry no less than 10% of its pretension load. Snug tight conditions can also be achieved with a few impacts of an impact wrench.

Can TC bolts be snug tight?

The RCSC Specification defines a snug-tightened joint as a joint in which the bolts have been installed in accordance with Section 8.1. Twist-off-type tension-control bolts can be used in snug-tightened joints, even if the splined ends are severed during installation.

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.

What is fully tensioned bolt?

The bolt will turn further than that – when it is turned to a non-zero setting on the torque wrench, it is a tensioned bolt. When it is tensioned to the enginerring spec, then it is “fully tensioned”. Above or below the spec then it is over or under tensioned respectively.

Does bolt orientation matter?

Normally it will not matter whether the bolt head or the nut is torqued. This assumes that the bolt head and nut face are of the same diameter and the the contact surfaces are the same (giving the same coefficient of friction). If they are not then it does matter.

What does wrench tight mean?

A wrench tight fitting has a head geometry that can be properly tightened with a wrench. It is important to specify the diameter from flat to flat side of the head to use the correct wrench. The 2 mostly used wrench tightening geometries are the Hex-head and the wrench flat.

Why is it needed for a slip-critical connection to be more snug tight?

It is estimated that a slip-critical connection costs about three times as much as a snug-tightened, bearing-type connection. The most common reason slip-critical connections are required is to limit the structural deformations possible when using oversized holes.

Does bolt direction matter?

Does it matter whether you tighten the bolt head or the nut? Normally it will not matter whether the bolt head or the nut is torqued.

What is turn of nut method?

Turn-Of-Nut is performed by rotating the nut or bolt of a fastener assembly a specific turn angle based on the fastener’s length, and diameter while restraining the unturned element from rotating.

What does 8.8 s bolt mean?

snug- tight
Category 8.8/S refers to any bolt of Property Class 8.8, tightened using a standard wrench to a ‘snug- tight’ condition in the same way as for category 4.6/S. Essentially, these bolts are used as higher grade commercial bolts in order to increase the capacity of certain connection types.

What is the definition of snug-tight bolt installation?

6.5.2. What is the definition of snug-tight bolt installation and when is it allowed? The RCSC Specification defines a snug-tightened joint as a joint in which the bolts have been installed in accordance with Section 8.1.

Do you need a snug inspection for turn of nut?

No further evidence of conformity is required for snug-tightened joints. If only hand tightening is used as a snug inspection criterion, it is possible for Turn-Of-Nut’s initial starting point, (i.e. adequate snug) will not be achieved and the method will fail. Such failures will not depend on whether fasteners were marked or not.

Do you need pretension for turn of nut bolts?

There is no pretension requirement for a “snugged” joint. Per AISC’s Specification for Structural Steel Buildings (360) Section J3: “There are no specific minimum or maximum tension requirements for snug-tight bolts.” The snug-tight condition is critical for the Turn-Of-Nut method since it relies on the snug position as its starting point.

Can a twist off bolt be used in a snug tightened joint?

There is no upper limit to the pretension that can be present in a snug-tightened joint. Twist-off-type tension-control bolts can be used in snug-tightened joints, even if the splined ends are severed during installation.