What is a prying action?
The term “prying” is used to indicate that the force in the bolt is greater than the applied force. Hence such joints can be prone to failure especially due to fatigue under repeated loading.
How can prying force be reduced?
The flexibility of connected parts can lead to deformations that increases the tension applied to the bolts. The additional tension is called prying force. The prying forces can be kept small by using a thick plate or by limiting the distance between the bolt and plate edge.
What is meant by slip critical connection?
In a slip-critical connection, loads are transferred from one element to another through friction forces developed between the faying surfaces of the connection. These friction forces are generated by the extreme tightness of the structural bolts holding the connection together.
What is block shear failure?
Block shear failure is a limit state that combines tension failure on one plane and shear failure on a perpendicular plane (Fig. 1). The guidelines assume that, when one plane reaches ultimate strength, the other plane develops full yield.
What are HSFG bolts?
HSFG bolts are high strength structural bolts which have been tightened such as to induce predefined tension in the bolt shank. Due to the tension in the bolt, the interface between the plies (steel members in a joint) cannot move relative to each other because of the frictional resistance.
What is the difference between slip-critical and bearing connection?
Slip-critical joint, from structural engineering, is a type of bolted structural steel connection which relies on friction between the two connected elements rather than bolt shear or bolt bearing to join two structural elements.
What is snug tight?
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. RCSC 2014, section 8.1 definition.
What is lug angle?
Lug angle is small piece of angle used to connect outstand legs of the members to the gusset plate. • The purpose of lug angle is to reduce the length of connection to the gusset plate and to reduce shear lag effect.
What is difference between HSFG and normal bolts?
Where a traditional bolt will stop the plates in a connection from moving apart by supporting the weight on the bolt shank in the form of shear stress, an HSFG supports the weight by clamping the plates so tightly together that they can’t slip past each other.
Why do you recommend HSFG bolt?
What is the purpose of slip-critical connection?
The most common reason slip-critical connections are required is to limit the structural deformations possible when using oversized holes.
What does snug tight mean?
Snug tight is defined by the AISC/RCSC as when all the plies in a connection have been pulled into firm contact by the bolts in the joint, and the bolts have been tightened sufficiently to prevent removal of the nuts without a wrench.
What is turn-of-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 does TF mean on a bolt?
fully tensioned
After (S) comes (TB) and (TF) – both of these represent “fully tensioned” bolts.
Why is lug angle not preferred?
The use of lug angle reduces the net area of main members due to the additional bolt holes in the projected member. This reduction in net area should not be excessive. In the connection of lug angle to the member or gusset plate, more than two bolts are used.
What is lug angle Why is it used?
Lug angle is small piece of angle used to connect outstand legs of the members to the gusset plate. The purpose of lug angle is to reduce the length of connection to the gusset plate and to reduce shear lag effect. area of the angle become effective in resisting tension.
What is the difference between end and edge difference?
The end of a blanket is where the longest measurement (length) ends. The side of a blanket is where the shorter measurement (width) ends. The edge is the very narrow thickness of the material of which the blanket is made and/or the area close to the edge.
What are the advantages of HSFG bolts?
The main advantages of HSFG bolted connections are their greater stiffness and their ability to withstand alternating forces. Their behaviour under fatigue loading is also better than that of bearing bolted connections. Against these advantages are the costs of HSFG bolted connections.