Apr 11, 2016

Structural parts are integral parts of sustainable constructions of infrastructure. They play an important part in ensuring structures are stable, and you should not install them lackadaisically. There are several options when it comes to structural bolts; however, you need to select these bolts carefully so as to ensure your needs are met. The two main purposes of structural bolts are:

•    Securing

Structural bolts help in securing parts in place so environment created is safe. You need to note how tight the fit should be so as to secure the parts safely. You could have negative effects when you screw the bolt too little or too tight.

•    Connecting

Structural bolts correspond to particular nuts so as to help stabilize and preserve the bolts which have three primary joint types:

  • Snug tightened joint

  • Pre – tensioned joints

  • Slip-critical joints

The kind of joint you are using will determine the connection that is needed. Handling, specification, design and inspection of structural bolts in your structures need to be by specification for structural joints using ASTM A490 or A325 Bolts by Research Council on Structural Connections.

For galvanized steel signs, you should use galvanized ASTM A325 structural bolts. The joints need to be between steel parts, and you need to properly pretension joints so they can resist vibration. These structural bolts usually have high strengths allowing them to supply high forces that help compress joints when tightened to pretension that has been prescribed. Thus, the structural joints will help maintain pre-compression and pretension of faying surfaces.

Installation of structural joints

All structural joints need to be installed following manufacturer’s requirements or established industry practice. For high strength bolt joints, RCSC recommends that surfaces need to be in firm contact though it is acceptable to have areas that have no contact. Despite the gaps in faying surfaces, the development of bolt preload will not be prevented. The thickness of the end plate is enough to develop the structural bolt tension that is desired.

When using ASTM A325 galvanized bolts, there are several methods of installation that are allowed and include;

  • Direct tension indicator method

  • Twist off type tension control method

  • Calibrated wench method

  • Turn off nut method

These methods have been described in section 8 of RCSC specifications. High strength structural bolts need to be inspected to ensure proper tightening following RCSC specifications of the method of installation that you are using.