Bolt Strength / Strength of Fasteners

Bolt Strength / Strength of Fasteners

When designing any bolted joint connection, the first thing we want to do is to ensure that we are specifying bolts that won’t fail under the expected design loads. In order to do this, we need to have an understanding of the properties that dictate bolt strength. Bolt strength, also known as load capacity, is governed by the material properties, the size of the bolt and the way in which the bolt is loaded. This section of the website provides information related to individual bolt strength under tension, shear and bearing. The topics covered are as followed:

Bolt Classification (Grades) – Steel A discussion of the metric bolt classification system in accordance with the guidance of the International Standards Organisation (ISO).
Proof Load / Tensile Strength of Bolts A presentation of methods for determining the proof load / nominal tensile strength of different bolt classifications and sizes. This sub-section presents a summary list of proof loads for common bolt classification and sizes.
Nominal Shear Capacity of Bolts A presentation of methods for determining the nominal shear capacity of different bolt classifications and sizes. This sub-section presents a summary list of shear capacities of common bolt classification and sizes.
Bearing Stress and Bolts  A discussion of the bearing stress considerations to be taken into account when loading bolts in shear; including a discussion on how to determine bearing stress in accordance with Eurocode 3, with an additional simplified approach. 
Strength of Screw Threads – Thread Stripping A discussion of thread stripping failure and how to avoid this failure mode through design.
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Basics of Bolted Joints Connection Types (Categories)