The forces in bolts are determined by finite element analysis. The tensile forces include prying forces. The bolt resistances are checked according to AISC 360 - Chapter J3.

### Bolts

#### Tensile and shear strength of bolts

The design tensile or shear strength, *ϕR*_{n}, and the allowable tensile or shear strength, *R*_{n}/*Ω* of a snug-tightened bolt is determined according to the limit states of tension rupture and shear rupture as follows:

*R*_{n} = *F*_{n}*A*_{b}

*ϕ* = 0.75 (LRFD, editable in Code setup)

*Ω* = 2.00 (ASD, editable in Code setup)

where:

*A*_{b} – nominal unthreaded body area of bolt or threaded part

*F*_{n} – nominal tensile stress, *F*_{nt}, or shear stress, *F*_{nv}, from Table J3.2

The required tensile strength includes any tension resulting from prying action produced by the deformation of the connected parts.

#### Combined Tension and shear in bearing type connection

The available tensile strength of a bolt subjected to combined tension and shear is determined according to the limit states of tension and shear rupture as follows:

*R*_{n} = *F'*_{nt} *A*_{b} (AISC 360-16 J3-2)

*ϕ* = 0.75 (LRFD, editable in Code setup)

*Ω* = 2.00 (ASD, editable in Code setup)

\( F'_{nt}=1.3 F_{nt} - \frac{f_{rv} F_{nt}}{\phi F_{nv}} \) (AISC 360-16 J3-3a LRFD)

\( F'_{nt}=1.3 F_{nt} - \frac{f_{rv} \Omega F_{nt}}{F_{nv}} \) (AISC 360-16 J3-3b ASD)

where:

*F'*_{nt}– nominal tensile stress modified to include the effects of shear stress*F*_{nt}– nominal tensile stress from AISC 360-16 Table J3.2*F*_{nv}– nominal shear stress from AISC 360-16 Table J3.2*f*_{rv}– required shear stress using LRFD or ASD load combinations. The available shear stress of the fastener shall be equal or exceed the required shear stress,*f*_{rv}

#### Bearing strength in bolt holes

The available bearing strengths, *ϕR*_{n} and *R*_{n}/*Ω*, at bolt holes are determined for the limit state of bearing as follows:

*ϕ* = 0.75 (LRFD, editable in Code setup)

*Ω* = 2.00 (ASD, editable in Code setup)

The nominal bearing strength of the connected material, *R*_{n}, is determined as follows:

For a bolt in a connection with standard holes:

*R*_{n} = 1.2 *l*_{c} *t* *F*_{u} ≤ 2.4 *d* *t* *F*_{u} (AISC 360-16 J3-6a, J3-6a, c)

For a bolt in a connection with slotted holes:

*R*_{n} = 1.0 *l*_{c} *t* *F*_{u} ≤ 2.0 *d t F*_{u} (AISC 360-16 J3-6a, J3-6e, f)

where:

*F*_{u}– specified minimum tensile strength of the connected material*d*– nominal bolt diameter*l*_{c}– clear distance, in the direction of the force, between the edge of the hole and the edge of the adjacent hole or edge of the material*t*– thickness of the connected material

### Preloaded bolts

The design slip resistance of preloaded class A325 or A490 bolt with the effect of tensile force Ft

Preloading force to be used AISC 360-10 tab. J3.1.

*T*_{b} = 0.7 *f*_{ub} *A*_{s}

Design slip resistance per bolt AISC 360-10 par. J3.8

*R*_{n} = *k*_{SC} *μ* *D*_{u} *h*_{f} *T*_{b} *n*_{s}

Utilization in shear [%]:

*U*_{ts} = *V* / *ϕR*_{n} (LRFD)

*U*_{ts} = *Ω V* / *R*_{n} (ASD)

where:

*A*_{s}– tensile stress area of the bolt*f*_{ub}– ultimate tensile strength- \( k_{SC}=1-\frac{F_t}{D_u T_b n_b} \) – factor for combined tension and shear (LRFD) (J3-5a)
- \( k_{SC}=1-\frac{1.5 F_t}{D_u T_b n_b} \) – factor for combined tension and shear (ASD) (J3-5b)
*μ*– mean slip factor coefficient editable in Code setup*D*_{u}= 1.13 – multiplier that reflects the ratio of the mean installed bolt pretension to the specified minimum bolt pretension*h*_{f}= 1.0 – factor for fillers*n*_{s}– number of the friction surfaces; Check is calculated for each friction surface separately*V*– shear force acting on the bolt*ϕ*= 1.0 – resistance factor for standard size holes (LRFD) editable in Code setup*ϕ*= 0.7 – resistance factor for slotted holes (LRFD)*Ω*= 1.5 – resistance factor for standard size holes (ASD) editable in Code setup*Ω*= 2.14 – resistance factor for slotted holes (ASD)