Bolt Count for Shear
Calculate the number of bolts needed to resist a shear force, n = F ÷ (A·τ_adm), from the total shear force to transmit F (N), each bolt's area A (mm²) and the material's allowable shear stress τ_adm (MPa). In structural and mechanical connections loaded in shear (beam splices, truss connections, flanges under lateral load, splice plates), the force is distributed among several bolts, each working in shear. The number needed is the total force divided by one bolt's shear capacity (area × allowable stress). The result is rounded up, and in practice a quantity is adopted that also meets minimum bolt spacing, edge distance and connection symmetry criteria. This calculation is the basis of designing bolted connections in steel structures (where it competes with welding) and in machines: it sets how many bolts and of what diameter are needed. There are other checks in the same connection: plate BEARING (contact pressure on the hole wall, which can tear the plate before the bolt shears), edge tear-out and the plate's own net-section strength (minus the holes). But bolt shear is the starting point. Enter the shear force, each bolt's area and the allowable stress.
Result
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Bolt count for shear
The number of bolts required to resist a shear force is n = F ÷ (A·τ_adm), from the total shear force to be transmitted F, the area of each bolt A and the allowable shear stress of the material τ_adm. In structural and mechanical connections loaded in shear (beam splices, truss joints, flanges under lateral load, splice plates), the force is shared among several bolts, each working in shear. The count needed is the total force divided by the shear capacity of one bolt (area × allowable stress). The result is rounded up, and in practice engineers adopt a quantity that also satisfies criteria for minimum spacing between bolts, edge distance and symmetry of the joint. This calculation underpins the design of bolted connections in steel structures (where bolting competes with welding) and in machinery: it fixes how many bolts and of what diameter are needed. Further checks follow on the same connection: plate bearing (contact pressure on the hole wall, which can tear the plate before the bolt shears), edge tear-out and the strength of the plate itself at the net section (discounting the holes). Still, bolt shear is the starting point. Enter the shear force, the area of each bolt and the allowable stress.
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