Design of Flexural Steel Members - Design of Modern Steel Railway Bridges - page 283

statically applied loads of the same or smaller magnitude will result in elastic behav-
ior (Brockenbrough, 2006). Therefore, except for fatigue considerations related to
dynamic live loads, residual stresses need not be explicitly considered in the design
of bending members such as plate girders. ∗

7.2.6.1.1.2 Tension Flange Splices AREMA (2008) recommends that splices
in the main members have a strength not less than that of the member being spliced.
It is also recommended that splices in girder flanges should comprise elements that
are not lesser in section than the flange element being spliced. Two elements in the
same flange cannot be spliced at the same location. †
Therefore, bolted ‡ splice elements in girder flanges should

• Have a cross-sectional area that is at least equal to that of the flange element
being spliced.
• Comprise splice elements of sufficient cross section and location such that
the moment of inertia of the spliced member is no less than that of the
member at the splice location.

Splice elements may be single or double plates. Single plate splices are generally
used on the exterior surfaces of flange splices to ensure a greater moment of inertia
at the splice. Two plates § are often used for larger girder splices where single-shear
bolted connections are too long and a double-shear connection is required.
The splice fasteners (see Chapter 9) should be designed to transfer the force in the
element being spliced to the splice material. Welded splices are usually made with
CJP (full penetration) groove welds with a strength that is at least equal to the base
material being spliced.

7.2.6.1.2 Girder Compression Flanges and Splices
7.2.6.1.2.1 Compression Flanges AREMA (2008) recommends that girder
compression flanges be designed based on the moment of inertia of the entire gross
section, I x g , and the tensile ∗∗ yield stress.
Therefore the plate girder gross section modulus, S x g ,is

I x g
c c ≥

M c max
F call

S x g = , (7.39)

where c c is the distance from the neutral axis to the extreme fiber in compression;
M c max is the maximum compressive bending moment due to all load effects and

∗ Residual stresses are also not explicitly considered in fatigue design because fatigue strength is based
on nominal stress tests on elements and members containing residual stresses from manufacture or
fabrication.
† This is usually only applicable to built-up section flanges, which are not often used for modern plate
girder fabrication.
‡ These may be shop or field splices.
§ It is good practice that the centroid of the splice plates each side of the flange plate be coincident with
the centroid of the flange being spliced.
∗∗ Tensile yield stress is almost equal to compressive yield stress (Chapter 2).