e-mosty December 2018 e-mosty December 2018 | Page 73

Figure 19: The design drawing of the Wuliting Bridge
The out-of-plane buckling calculation results show
that the main arch ring has enough flexural-torsion
buckling resistance, with a safety factor K > 8 during
the construction process and K > 4 in the operation
stage.
This construction method was applied to this CFST
tied arch bridge for its safety and economy, and was
proven as a qualified construction method following a
thorough detail inspection checks results in 2014 of
this arch bridge.
CONSTRUCTION INNOVATIONS
Construction technologies
For the concrete post-tensioning system, seven
parallel wires of 7mm diameter were prestressed. The
proprietary ‘HM’ anchor system was used for the
prestressed anchor system, which included fixed ends,
tension ends and a special connector between the
fixed anchor and tension anchor. The fixed ends of
this system were DM7-84 anchors and the tension
side were an OVM21-12 anchor, as shown in Figure
22. The temporary construction analysis also showed
that HM anchors were suitable for prestressing of
incremental launching box beam.
Incremental Launching Method in Tied Girders
In the construction stage, two tied girders were
divided into six parts along the bridge longitudinal
axis, each section was a 20-34m box beam which was
split into 8-9 box precast segments. The box girder
casting yard was positioned in the centre of the
ground on the approaches to the bridge, and a 60 m
steel truss beam was selected as an assembly
platform, as shown in Figure 21. It took 12-15 days to
build up each box beam, and the average incremental
launching speed was 3m per day.
Figure 21: Box girder casting yard and assembly platform
4/2018