StructX > Design Tables > Bolt Design > Bolt Capacities

Strength Limit State

Bolted connections can be subjected to three main force groups as well as combinations of these which all need to considered in every connection design and assessment. The three main force groups which can be found to act on connections are Shear and Bearing, Friction and Axial Tension. The below table has been provided as a rough guide to the capacities of individual shear and axial tension that bolts can withstand.

For connections that are subjected to multiple forces an appropriate interaction equation should be used from a suitable source, such as a standards organisation or subject expert.

The above table is based on metric bolt grades but can be used as a guide for equivalent grade bolts as well. It should be noted that some equivalent grades have slightly lower capacities (in the order of 9%) which may need to be taken into consideration also. Some of the equivalent bolt types are as follows:

• Bolt Grade 4.6: SAE J429 Grade 1; ASTM A 307 Grade A
• Bolt Grade 8.8: SAE J429 Grade 5; ASTM A 325 (types 1,2 & 3)