The Beipanjiang River is a
barrier that seems to require engineers to create world record bridge spans.
This tradition began in 2001 when the first record breaking high railway arch
crossing took place near Fa’er Bouyei with a rail to river drop of 275 meters.
Things have changed a lot in China between 2001 and 2015 and most of the newer
railway lines are being designed and built for high speed trains reaching
speeds of 250 kilometers an hour.
The massive Beipanjiang River
railway arch is not only the world's highest railway bridge at 283 meters if
you exclude Najiehe which is over a reservoir, but is also the world's longest
concrete arch ever built with a span of 445 meters. The crossing is the crown
jewel of bridges on the high speed railway line connecting Guiyang and Kunming.
Located north of Qinglong city, the Beipanjiang has always been Guizhou's
second greatest river after the Wujiang.
Designed to carry trains that
will reach speeds of 250 kilometers an hour, the 721 meter long crossing has a
main arch with a rise of 100 meters and a rise to span ratio of 4.45. The arch
ring cross section has three cells within a single-box with equal depth of 9
meters and a variable width of 18 to 28 meters. The width of the arch at the
springing is 28 meters while the width of the arch at the crown is 18 meters.
Double-column framed piers are used for supporting the deck. The piers rise 102
meters at the abutments with the tallest spandrel column on the arch rising 59
meters. Steel tubular trusses filled with concrete were used as a skeleton
during construction before it was encased in concrete. The stay cables placed
at the abutment pier were post-tensioned step by step during the
concrete-pouring to assist the skeleton in load carrying.
The approach bridges are 5.6 +32
+2x65 +4x42 +4x42 +2x65 +2x37 +6.6 meters prestressed concrete continuous
beams. The dual line width of unballasted track is 4.6 meters wide and crosses
the Beipanjiang River just below the Guangzhao Dam.
The deformation of the arch ring
increased gradually as the volume of arch ring concrete increased during the
construction process. The maximum deflection was designed to be 294mm after
pouring of the arch ring concrete was completed and 383mm after the additional
dead load was placed. Because live load accounts for a small proportion of dead
load, precamber of the arch ring is designed based on the deformation caused by
dead load. At the arch crown, the precamber of 350mm is set, while the cambers
of other parts of the arch ring are distributed by quadratic parabola. Under
the standard railway live load, the maximum upward vertical deflection is
40.2mm which occurs at the quarter-span section and the maximum downward
vertical deflection is 48.8mm which also occurs at the quarter-span section.
Under the lateral wind load, the maximum lateral displacement is 52.8mm which
occurs at the mid-span section.
The bridge is located at
kilometer 882 and cost 430 million Yuan or 66 million dollars. The Beipanjiang
Railway Bridge is a sister bridge to the slightly smaller Nanpanjiang Railway
Bridge near Qiubei, Yunnan as they were both designed by the same engineering
teams with similar designs and construction methods. The major difference
between the two spans is the Beipanjiang Bridge arch rib has a depth of 9 meters
while the Nanpanjiang arch rib has a depth of 8.5 meters.
Beipanjiang Railway Bridge
Qinglong Elevation
The span of steel tubular truss
is 445m. It is longitudinally divided into 40 segments for lifting and the
length of each segment is 12m. The truss is made of the upper and lower chords
of 8 steel tubes with a diameter of 750mm and a thickness of 24mm.Image by Eric
Sakowski / HighestBridges.com
thuyloivn.com st
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