Arch bridges - Computational Analysis and Design of Bridge Structures - page 292

9.6 3d ILLustrAted exAMPLe of A ProPosed
tIed-Arch brIdge AnALYses —LInYI,
PeoPLe's rePubLIc of chInA
As an arch bridge stability analysis example, later in Section 14.6 stability
analyses of a proposed concrete-filled steel tube tied-arch bridge will
be demonstrated. In that example, three stages are modeled as shown in
Figures 14.16 and 14.17. Stage 1 is the casting of tied girder concrete on
falsework; stage 2 is the installation of arches and lateral bracings, filling
concrete into steel tube, and first-time jacking of hangers; and stage 3 is the
installation of the deck and final jacking of hangers.
In addition to construction analyses of these stages and the stability anal-
ysis, live load analysis is also performed by using influence surface loading
method. Figure 14.16 shows the axial force distribution of the live loads
that cause the compression on top of one arch maximal. 3D modeling and
influence surface loading clearly illustrate the lateral distribution of live
loads. As shown in Figure 14.16, the maximum compression on top of one
arch is 822 kN, whereas the corresponding compression on the other side
is only 149 kN. Figure 14.17 similarly shows the uneven displacements on
both tied girders due to live loads.
9.7 3d ILLustrAted exAMPLe of An Arch
brIdge—LIujIAng YeLLow rIver brIdge,
zhengzhou, PeoPLe's rePubLIc of chInA
Liujiang Yellow River Bridge, crossing over Yellow River at Zhengzhou,
China, was built in 2006. The bridge has a length of 9848 m in total and
eight lanes carrying two bounds traffic. Most spans are simply supported
prestressed concrete T girder and void slab spans. The main bridge con-
tains four spans of concrete-filled steel tubular tied-arch spans, as shown
in Figure 9.20. Traffic lanes of two bounds are separated. Each of the arch
spans carries four traffic lanes with a net width of 19 m. The total width is
24.377 m, and the span length is 100 m.
In this example, the dead load and live load analyses of one arch span are
introduced. The theoretical span length is 95.5 m, and a catenary arch with
a factor of 1.347 is used. The ratio of arch rise to span is 1:4.5. The arch
contains two vertically placed steel tubes connected by steel plates. After clo-
sure, the tubes and connecting rib are filled with concrete. The tied girders
and end-floor beams are prestressed concrete box girders; the interior floor
beams are prestressed concrete T girders. The deck comprises precast con-
crete Π modular slabs, placed on top of floor beams and connected to each
other by cast-in-site segments. The hangers are high-strength steel wires.