Applied Loads and Stability of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 198

1 : 5 f u dt

g M2

F b , Rd ð 3 : 110 Þ

where d is the nominal bolt diameter. In the case of class 8.8 or 10.9 bolts,
hardened washers should be used for single-lap joints with only one bolt or
one row of bolts. Where bolts transmitting load in shear and bearing pass
through packing of total thickness t p greater than one-third of the nominal
diameter d , the design shear resistance F v,Rd should be multiplied by a reduc-
tion factor b p given by
b p ¼

9 d
8 d +3 t p

with b p 1

: ð 3 :

111 Þ

0

For double-shear connections with packing on both sides of the splice, t p
should be taken as the thickness of the thicker packing.
For slip-resistant connections using class 8.8 or 10.9 bolts, EC3 (BS EN
1993-1-8) [2.13] specifies that the design slip resistance of a preloaded class
8.8 or 10.9 bolt should be taken as

k s nm
g M3

F s , Rd ¼ F p , C ð 3 : 112 Þ

where k s is given in Table 3.24 , n is the number of the friction surfaces, and m
is the slip factor obtained either by specific tests for the friction surface or
when relevant as given in Table 3.25 . For class 8.8 and 10.9 bolts with con-
trolled tightening, the preloading force F p,C to be used in Equation (3.112)
should be taken as

F p , C ¼ 0 : 7 f ub A s ð 3 : 113 Þ

Table 3.24 Values of k s Specified in EC3 (BS EN 1993-1-8) [2.13]
Description k s

Bolts in normal holes 1.00

Bolts in either oversized holes or short slotted holes with the
axis of the slot perpendicular to the direction of load transfer

0.85

Bolts in long slotted holes with the axis of the slot perpendicular
to the direction of load transfer

0.70

Bolts in short slotted holes with the axis of the slot parallel to the
direction of load transfer

0.76

Bolts in long slotted holes with the axis of the slot parallel to the
direction of load transfer

0.63