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Steel Designers' Manual - 6th Edition (2003)
112 Industrial steelwork
top
bottom
plate girder
lood—bearing
stiffener
Fig. 3.9 Rocker bearing – plate girder to box column
\actuaI bearing
width
detailed section
of rocker
plan on cap plate
location
keep
plates
bearing
area
(shaded)
Connection design for normally-sized members should not vary from established
practice, but for the large box and plate I-section members that are used in major
industrial steel structures, connections must be designed to suit both the member
type and the design assumptions about the joints. For particularly deep beam
members, where plate girders are several times deeper than the column dimensions,
assumed pin or simple connections must be carefully detailed to prevent inadvertent
moment capacity. If this care is not taken, significant moments can be introduced
into column members even by notional simple connections due to the relative
scale of the beam depth.
In certain cases it will be necessary to load a column centrally to restrict bending
on it: a typical example is where deep suspension girders on power station boilers
apply very high vertical loadings to their supporting columns. Here, a rocker cap
plate detail is often used to assure centroidal load transfer into the column (Fig.
3.9). Conventional connections on smaller-scale members would not usually require
such a precise connection as load eccentricities would be allowed for in the design.
3.2.7 Bracing, stiff walls or cores
Section 3.2.2 discusses the particular features of industrial steel structures in relation
to achieving a horizontal or sway load path and describes the various methods