slotted hole installation requirement 3

[TTTKAO]

Hello All,

Thank you for your attention and time for this topic, I have two questions regarding to bolt installation requirement when using AISC code.

1. if i set slot hole to release the load in one direction. i should select snug tighten bolt only, right ? is there specific clauses in AISC 360 or RCSC to address this condition?
2. for clause J 1.10(2) in AISC-360 10, this is one condition have to use pretensioned bolt or weld. the condition is "connections of beams and girders to columns and any other beams and girders on which the bracing of columns is dependent in structures over 125ft in height. what does this condition mean?

Thank you for help in advance!

Regards!

 

[BridgeSmith]

It depends on how easily it needs to be able to slide. If you want it to be truly free, you'll need to specify hand tight, and require something to keep it there (threadlocker compound, jam nut, etc.). Snug tight, which is which is usually defined rather loosely using terms like "the full effort of a worker using a XX" wrench" so the connection can have significant resistance to slipping.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[HTURKAK]

From the Glossary of AISC 360-16,

Slip-critical connection= Bolted connection designed to resist movement by friction on the
faying surface of the connection under the clamping force of the bolts.

Snug-tightened joint= Joint with the connected plies in firm contact as specified in Chapter J.

..and the relevant clause for hand tightening ;

There are practical cases in the design of structures where slip of the connection is desirable to allow for expansion and contraction of a joint in a controlled manner. Regardless of whether force transfer is required in the direction normal to the slip direction, the nuts should be hand-tightened with a spud wrench and then backed off one-quarter turn. Furthermore, it is advisable to deform the bolt threads or use a locking nut or jamb nut to ensure that the nut does not back off further under service conditions

IMO, it is more than clear..












Tim was so learned that he could name a
horse in nine languages: so ignorant that he bought a cow to ride on.
(BENJAMIN FRANKLIN )

 

[dik]

from my notes, and I edit as needed:

NON-REMOVABLE BOLTS
-ALL FASTENERS, SUPPORTING MECHANICAL EQUIPMENT, WHERE THE NUTS ARE LOADED IN TENSION ARE TO BE SECURED USING LOCTITE 263 (RED) THREAD LOCKER OR THE THREADS SHALL BE PEENED TO PREVENT LOOSENING.
-EOR/ARCH TO CONFIRM BOLTS FOR ‘SLIDING’ CONNECTIONS MAY CONFORM TO ASTM A307, GRADE B, AND SHALL BE FINGER TIGHT. TORQUE TO 27KN-MM (20FT-LBS). PROVIDE SLOTTED CONNECTIONS AS REQ’D.
-DIAMETER AND QUANTITY AS SHOWN. SECURE BY PEENING, OR LOCTITE 263 (RED) THREAD LOCKER.


-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[TTTKAO]

thank you so much all for your sharing. Appreciate it a lot.

 

[dik]

I design connections for a metal fabricator, and occasionally have connections where bolts are loaded in tension with mechanical equipment. I don't care if the equipment vibrates, I want to 'glue' the nuts in place. I don't want them to vibrate loose. The reason for the A307 reverence is that EORs often spec A325, for everything... and, I want the EOR to take ownership for the revision, not my client. I don't use jam nuts if I can avoid them.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik