Symbols

Ab: Non-threaded bolt characteristic cross-sectional area

Aw: Cross-section web area

Ag: Gross area

Ae: Effective net area

An: Net area

Agv: Gross shear area

Anv: Net shear area

Ant: Net tensile area

Cv: Coefficient of reduction for shear buckling

d: Characteristic of bolt diameter

dh: Bolt hole diameter

Fy: Specified yield stress of the type of steel being used, ksi (MPa)

Fu: Specified ultimate stress of the type of steel being used, ksi (MPa)

Fnt: Characteristic tensile tensile strength given in Table 13.7

F'nt: Reduced characteristic tensile stress obtained by considering shear force effect

Fnv: Characteristic shear stress strength given in Table 13.7

frv: The greatest shear stress in the characteristic thread area of ​​the bolt under YDKT or GKT load combinations

Fyb: Bolt characteristic yield strength

Fub: Bolt characteristic tensile strength

nsp: Number of shear planes

Ubs: A coefficient considering the distribution of tensile stresses

s: Distance between bolt holes center

Le: The distance from the center of the bolt hole to the edge of the connected element

t: Plate thickness

Rnt : Characteristic tensile strength

Rnv : Characteristic shear strength


Design Criteria for Shear Connection

  • It is assumed that the entire shear force is resisted by the web of the cross-section.

  • There is no interaction between shear force and bending moment.

  • Shear strength is determined using the formula:

Shear Strength

  • In stiffened and unstiffened single and double symmetrical cross-sections, the characteristic shear strength in the web is calculated as follows:

  • The coefficients for the I-cross section elements according to the slenderness ratio are determined as follow:

  • The allowable shear strength is calculated as follow:

Bearing Connections

  • In the bearing connections, the strength is determined according to the smallest one by controlling 3 limit conditions.

  • Shear failure at bolt.

  • Bearing limit state in the plate.

i) Tear-out limit state of the plate.

ii) Bearing limit state of the plate.

Characteristic Tensile and Shear Stress Strengths of Bolts

  • Characteristic tensile strength Fnt of bolts is calculated depending on the characteristic tensile strength of bolt material Fub given in Table 2.2.

  • The characteristic shear stress strength of bolts, Fnv, is calculated in two different ways:

i) If the threaded part of the bolt is in the shear plane.

ii) If the threaded part of the bolt is outside of the shear plane.

Characteristic Tensile Force Strength of Bolt Under the Combined Effect of Tensile and Shear Force

  • The characteristic tensile force or shear strength of prestressed high strength bolts, simple tightened bolts and threaded cross sections are calculated according to the rupture limit state for the tensile forces or and tear-out limit state for shear forces.

Bearing Connections under the Combined Effect

Bearing Limit States in the Plate (Bolt Holes)

  • The compressive stresses that occur between bolt and plate are because of excessive deformations on the bolt and plate.

  • In order to compute the bearing stress ​​between the bolt and the hole edge, the assumption of uniform distribution of stresses on this surface is defined.

Bearing Failure of the Bolt Hole

Tear-out Failure of the Plate

  • The characteristic bearing force resistance Rn of a bolt hole is calculated based on the bearing limit state under the shear effect as follow:

  • Regardless of the direction of the load, for connections formed from standard, oversized and short-slotted holes or long-slotted holes with oval longitudinal axis parallel to the direction of the load:

  • For connections formed with slotted holes with oval longitudinal axis perpendicular to the direction of the load:

  • Safety factors depend on the method being used:

Shear Resistance

  • The characteristic shear strength Rn of the cross-section and connection elements under shear effect for the yield and rupture limit states calculated as follow:

Yielding Limit State

Rupture Limit State

Block Shear Limit State

  • The characteristic block shear strength Rn is calculated on the basis of the yield and rupture limit states along the shear surface or surfaces and the rupture limit states along the tensile surface.

Tensile Strength

  • The characteristic tensile strength Rn of the cross-section and connection elements under the shear effect for tensile action is calculated for the yield and rupture limit states as follows:

Yielding Limit State

Rupture Limit State