Calculation Of High-Strength Bolt Length

The following factors shall be taken into account when calculating the length of high-strength bolts:

Total thickness of connected members: Sum of the thicknesses of all stacked connected components, unit in millimeters (mm).

Nominal bolt diameter: Nominal diameter of the selected high-strength bolt, unit in millimeters (mm).

Thickness of washers and nut: Including the thickness of matched plain washers and nut.

The preliminary calculation formula for high-strength bolt length is as follows: Preliminary bolt length = Total thickness of connected members + Total thickness of washers + Nut thickness + Projection length of bolt shank beyond nut

It should be noted that the threaded shank of a high-strength bolt shall extend 2 to 3 pitches beyond the nut face, generally taken as 0.3 ~ 0.5 times the nominal bolt diameter. After length calculation, the nominal bolt length shall be selected to the nearest standard bolt length series, and relevant national codes and specifications shall be followed. Please perform calculation according to project parameters to meet the requirements of engineering specifications and construction acceptance.