A307 Bolts - Strength Reduction Based on Grip Length

[mcc202]

AISC Steel Construction Manual Table J3.2 specifies that the nominal tensile stress and nominal shear stress shall be reduced for A307 bolts based on the grip length of the bolt in the connection. This is specified in footnote in this table. Why is this? This reduction gets very significant for large bolt lengths.

Thanks

 

[connectegr]

An A307 bolt performs poorly on bending or tension. And A307 bolts are not pretensioned to provide a strict shear plane. As the bolt gets longer the force on the bolt is more shear and tension.

We never use A307 bolts for structural applications, so this is just my assumption.

http://www.FerrellEngineering.com

 

[mcc202]

Thanks. It appears that this footnote was removed for tensile stress in the 14th edition. Here is the explanation I received from AISC:

"The footnote you mention only applies to the shear strength of A307 bolts. The reason for this reduction is explained in the Commentary to Section J3.6 of the 2010 AISC Specification, which states,

In Table J3.2, footnote c, the specified reduction of 1% for each 1/16 in. over 5 diameters for ASTM A307 bolts is a carryover from the reduction that was specified for long rivets. Because the material strengths are similar, it was decided a similar reduction was appropriate."

 

[amec2004]

>> We never use A307 bolts for structural applications, so this is just my assumption

It's common on anchor bolt application. We purposely use A307 bolt to achieve anchor bolt ductility



anchor bolt design crane beam design

http://www.civilbay.com