Bolted Joint Shear Stress
Shear Stress in a Bolted Joint
Bolts and rivets in a lap or splice connection carry load primarily in shear across their shanks. This worksheet finds the average shear stress per bolt and the factor of safety against an allowable shear value.
The average shear stress is τ = V/(n·A), where V is the transferred force, n the number of bolts sharing it and A the shear area of one bolt.
Inputs
V := 25 kN=25000 N
d := 16 mm=16 mm
n := 2=2
tau_allow := 120 MPa=120 MPa
Bolt shear area and stress
A := pi·d^2/4=2.01e-04 m^2
tau := V/(n·A)=62.17 MPa
Factor of safety
SF := tau_allow/tau=1.93
Results
A factor of safety above 1 means the joint is within the allowable shear; typical mechanical practice targets 1.5–2.5 on bolt shear depending on the code and load certainty. Also check bearing on the plate and tear-out, which often govern over bolt shear.
Assumptions & limitations
- Load shared equally between identical bolts.
- Single shear plane through the full shank area (use the thread root area if the plane crosses the threads).
- Bearing, tear-out and slip checked separately.