Suspension bridges - Computational Analysis and Design of Bridge Structures - page 391

When using the simple truss element, the main cables have at least to be
meshed at the hanger locations. For longer spacing of hangers, cable has
to be meshed in between hangers. Generally speaking, a meshed cable seg-
ment length of 10 m is adequate considering the long span of a suspension
bridge. Along with the way the cable is modeled, how the initial stress and
large displacement iteration are considered should be clearly understood.
When a cable segment between two adjacent hangers is submeshed, for
example, the analysis may fail as there may be no stiffness perpendicular to
the cable initially if the initial stress is not addressed correctly.
As discussed in Sections 12.3.4 and 12.3.5, features regarding how the
zero-stress state is obtained by iterations and how saddle curves are consid-
ered in the analysis tool should be studied too.
12.4.2 hangers
The hangers are simple components and can be simply modeled as single
truss elements. For rigid connections between main cables and the stiffened
girder in the middle of the main span as shown in Figure 12.15, truss or
beam elements can be used.
12.4.3 Stiffened girder
The modeling of stiffened girders is similar to the main girder of a cable-stayed
bridge. For a box girder, as shown in Figure 11.23 of Chapter 11, the fish bone
model as shown in Figure 11.24 of Chapter 11 can be used. The transverse
Figure 12.15 Rigid connections between main cables and stiffened girder (Runyang Bridge,
China). (Data from Ji, L. and Feng, Z., Construction of Suspension Bridges across
the Yangtze River in Jiangsu, China , IABSE Workshop—Recent Major Bridges,
May 11-20, 2009, Shanghai, People's Republic of China.)