Calculating Shear Strength of Grade 8 Bolts
A common question that we get here at Portland Bolt is in regards to the shear strength of bolts. The shear strength is the value at which the lateral stress on a bolt or screw causes it to fail. It is an important factor to take into consideration when designing structural steel or timber connections. Shear strength is also an easy value to roughly calculate when the ultimate tensile strength is known.
Below is a transcript of a recent live chat that we had on our website addressing shear strength. The chat was fielded by our very own Dane McKinnon and serves as a good example of what kind of response you can expect when you ask us a question. We’re substituting a generic name below for the customer to protect their privacy.
- Visitor: Henry
- Operator: Dane McKinnon
- Company: Portland Bolt
- Started: 26 Jan 2010 12:07:57
- Ended: 26 Jan 2010 12:22:18
What is the shear strength of grade 8 bolts 1/4″ – 1″
Good afternoon Henry. Shear strength is typically 60% of tensile strength, and the minimum tensile strength of a grade 8 bolt is 150,000 psi. We have an FAQ that addresses this question here: http://www.portlandbolt.com/faqs/bolt-shear-strength-considerations
How are all grade 8 bolts the same tensile strength?
They are all the same tensile strength per square inch. The larger ones have a larger cross section of material, and so are therefore stronger. To calculate the tensile strength of a particular size, you would multiply 150,000 psi by the tensile stress area, found here: http://www.portlandbolt.com/technicalinformation/thread-pitch.html
Have a bolt related question of your own? Try our live chat feature and get the answer you need quickly.