Applied Loads and Stability of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 192

3.10 DESIGN OF BOLTED AND WELDED JOINTS
3.10.1 General
The previously mentioned brief survey of the design rules specified in the
current codes of practice provided a general background to the design of
main components of steel and steel-concrete composite bridges. However,
in order to get a complete background, it is also important to review the
design rules on how these components are connected together, that is,
the design of joints connecting the different components. Therefore, in
the succeeding sections, it is decided to highlight the design rules specified,
as an example, in the Eurocodes on bolted and welded joints. According to
EC3 (BS EN 1993-1-8) [2.13], all joints shall have a design resistance such
that the structure is capable of satisfying all the basic design requirements
given in EC3 (BS EN 1993-1-1) [2.11]. The partial safety factors g M for
joints are given in Table 3.21 . The forces and moments applied to joints
at the ultimate limit state shall be determined according to the principles
in EC3 (BS EN 1993-1-1) [2.11]. EC3 (BS EN 1993-1-8) [2.13] specifies
that the resistance of a joint should be determined on the basis of the resis-
tances of its basic components. Linear-elastic or elastic-plastic analysis may
be used in the design of joints. Joints shall be designed on the basis of a real-
istic assumption of the distribution of internal forces and moments. The
main assumptions used to determine the distribution of forces are as follows:
(a) the internal forces and moments assumed in the analysis are in equilib-
rium with the forces and moments applied to the joints, (b) each element

Table 3.21 Partial Safety Factors for Joints Specified in EC3 (BS EN 1993-1-8) [2.13]
Resistance of members and cross sections

g M1 , g M1 , and g M2

Resistance of bolts g M2

Resistance of rivets
Resistance of pins
Resistance of welds
Resistance of plates in bearing
Slip resistance
- At ultimate limit state (category C)
- At serviceability limit state (category B)

g M3
g M3,ser

g M4

Bearing resistance of an injection bolt

Resistance of joints in hollow section lattice girder g M5

g M6,ser

Resistance of pins at serviceability limit state

Preload of high-strength bolts g M7

Resistance of concrete g c