Guizhou Province Liuguanghe Bridge Construction and Design Nguyen strong Xiewan Chen Lian Zhong Rong Zeng Tao Zhang Xin (Guizhou Province Bridge Engineering Corporation) Abstract: This paper describes the design Liuguanghe bridge and expansion of basic, 90m high pier construction process, 240m span continuous rigid frame Girder cantilever construction technology and measurement control methods. Keywords: Liuguanghe continuous rigid frame bridge construction control

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Nov 25, 2013 (3 years and 10 months ago)

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Guizhou Province Liuguanghe Bridge Construction and Design

Nguyen strong Xiewan Chen Lian Zhong Rong Zeng Tao Zhang Xin (Guizhou
Province Bridge Engineering Corporation)

Abstract: This paper describes the design Liuguanghe bridge

and expansion of
basic, 90m high pier construction process, 240m span continuous rigid frame

Girder cantilever construction technology and measurement control methods.

Keywords: Liuguanghe continuous rigid frame bridge construction control
stiffness desig
n



I. Overview

Liuguanghe Bridge is located in Xiuwen County, Guizhou Province Liuguanghe
Scenic, Guiyang
-

Bijie vehicle for two roads across six broad river gorge a large
bridge. The main bridge across 240m, 145.1m side span prestressed concrete
continu
ous rigid frame, where the 2nd pier height 90m. Approach of 20m
prestressed hollow simply supported plate, a length of 564.2m (see Figure 1).
The bridge is also the first in Guizhou province's roads and bridges containing
environmental design. Bridge, whic
h is a river erosion valley landforms, deep
valleys, the relative elevation of about 300m, the lower U
-
shaped valley (about
80 to 90 degrees into the cliffs), the upper V
-
shaped (about a 30 to 45 degree
slope), rock bridge site single, for the Permian unde
r the EC Chihsia flint
limestone, locally layer sandwiched between broken horn sparkle rock, rock
mass along the rock level and joint surface denudation is well developed, often in
the rock level and joint surface formed near the dissolved pore solution ga
p
(width 10 ~ 2Ocm), part of the expansion of the formation of karst caves, cave
high 0.2
-
2.7m, interconnected, boreholes see one to four layers of soluble gap
cave, which see the full filling, half filled or empty, filling both gravel clay, loose
structur
e. The cave is corrosion cracks and small caves constitute irregular, very
irregular borders surrounding complex. Liuguanghe bridge started in November
1999, October 2001 full
-
bridge opened to traffic.


Second, the structural design

1, the upper structure
design

Upper structure of variable cross
-
section single
-
box single chamber dual
cantilever box girder (Fig. 1), the whole bridge girder section is divided into 0 No.
1
-
the 28th beam segment, cast segments and closed sections. Box top width of
13m, bottom w
idth of 7m. Box No. 0 high beam segment 13.4m, folding segment,
while cross
-
cast segments 4.1m, the rest of the cantilever beam segment from
the root to the end, according to semi
-
cubic parabola changed from 13.4m to
4.1m. Thick roof girder beam segment nu
mber other than 0 is 5Ocm, beam end
bearing section of 1O2cm, the rest are 28cm, and a two
-
way cross slope of
1.5%. Thick plate girder beam segment number 0 is l60cm, cantilever root of
145cm, folding segment of 3Ocm, from the roots to the ends of the boom
,
according to semi
-
cubic parabola changed from 145cm to 3Ocm. Cross
-
section
of side plate thickness from 3Ocm cast changes to 7Ocm, during which the
straight
-
line change. Web thickness 0 No. beam segment l00cm, cantilever root
to ends by 7Ocm, 60cm, 4Ocm
mutations in three sizes, side cross
-
cast
segments from 40cm to l40cm straight line gradient.

2, the lower structural design

The 1st, the 2nd main pier pier holes, the 1st bridge pier height 73m, 2, Bridge
Pier Height Wm. Each pier by the two transverse di
rection width 7m, along the
bridge to 3m thick walled rectangular reinforced concrete pier composed of two
thin
-
walled pier spacing between 8m. Because piers higher, stable at room
features two thin
-
walled pier and pier width, 2.2m thick horizontal tie bea
m. The
1st pier located a horizontal tie beam, the 2nd pier located two horizontal tie
beam, so the overall stiffness of nearly two piers. Walled pier from the bottom to
the horizontal tie beam (the 2nd pier to the second cross
-
tie beams) as a solid
rectan
gular cross
-
section, for more than a hollow rectangular cross
-
section


3, basic design

Liuguanghe bridge base were expanded base. As the basis of the two main piers
were placed on both sides of the cliff, the first consideration when designing pier
foundat
ion is exposed at the rock formations in the overall stability of bridge load
after, followed by the carrying capacity of the bedrock, construction conditions,
etc., After considering the decision to expand the use of open
-
cut base. The 1st
pier foundation

thick 5m, 2 pier foundation pier height is set to reduce the two
layers, each 5m, two piers are embedded bedrock base.

Third, the prestressing system and Stress Analysis

Liuguanghe bridge Upper Box to a three prestressed concrete structure, the
lower part

of reinforced concrete structures. Designed to divide it into vertical and
horizontal frame with rigid frame plane frame program for stress analysis.
Longitudinal girder prestressed concrete structures by the whole design of box
girder in operation when t
he tension side still leave some stress. Longitudinal
prestressing system 15.24m prestressing strand with 22 holes designed
tensioning tonnage of 4297kN, each T is set to bundle cable 112, the cable 26
-
span continuous beam, side
-
span continuous beam cable
16. Partially
prestressed by Transverse Class B component design, operation under the most
unfavorable load combination tension generated by the transverse prestressing
strands and ordinary reinforced shared. Also used 15.24mm transverse
prestressing stran
d, tensioning end uses BMl5
-
3 flat anchor system, fixed end
use ginning anchor, tensioning end and a fixed end staggered layout, design
tension tonnage 508kN. Girder vertical bars using φ32 finishing coarse thread.

Longitudinal stress analysis considering
static wind loads wind pressure
generated due to the design of the bridge is located at no observed data, and
thus the value according to specifications, the basic wind pressure to take 400Pa
(ie wind speed 25m / s), respectively, for the wind direction is

along the bridge to
, the transverse direction and construction boom when the maximum pressure on
both sides of the state for different calculations.

Uniform temperature load longitudinal temperature change by ± 20

considered
uneven temperature change b
y +33.5

,
-
28.4

considered. Transverse frame
calculation temperature change by ± 10

and 5

temperature difference into
account.

As Liuguanghe bridge two main pier height were 73m and 90m, the same type of
bridge is still relatively rare, so the high
pier force analysis is particularly
important. Taken into account in the calculation of pier each construction stage
two cantilever load difference a block piece floor and two cantilevered weight
difference of 5% impact on the pier, taking into account the

maximum cantilever
segmental construction plus the impact of wind load, considering prestressed
Steel beams and piers of temperature change on the impact of cross
-
tie beam.

Pier for high stability during construction with SAP97 program in three conditions

calculated.

Condition One: across the side loads from 1 to 27 weight beam segments (5%
considered overweight) +28
.


Number plate girder section re + Cradle, side load side span of 1 to 27 weight +
Cradle beam segment.

Condition 2: The cross
-
Side Load 1 to

the 27th beam segment weight (5%
considered overweight) No. +28 + Cradle heavy plate girder section, side load
side span of 1 to the 27th beam segment weight.

Three conditions: condition a + wind loads.

Minimum safety factor calculation is 8.42, occurring

in the 1st pier condition three
o'clock, because there is no bridge design specifications of the continuous rigid
frame bridge piers provided for stability, so the design specification for the cable
-
stayed bridge with a cable
-
stayed bridge tower body stru
cture to control the
stability criteria.

Fourth, the foundation construction and handling

Since the bridge is across from Guiyang to Bijie highway opened to traffic control
engineering, started too late, sinister construction environment, temperature
chang
es, to ensure your complete road traffic but also strive Buyou time of the
construction unit project which made a very high requirements. Careful analysis
of the construction unit of the whole bridge site during construction and after the
field visits, agr
eed that although the bridge construction period control in the
upper box girder construction, but the construction of the superstructure is to
determine the duration of child almost not able to compress, to assurance on
schedule to complete construction o
f the substructure must think of ways.

1,2 pier foundation to expand the large amount of rock excavation, because the
underlying at the edge of the canyon, near the excavated rock shall be stacked,
are not allowed to give up to six broad river, all the car
s moved away (design
environmental requirements), so install two QT125
-
type tower crane, tower crane
hoisting stonework to transfer directly from the car, then it picked up speed and
solve the difficulties of construction is smaller. While relying on the v
alley side to
build three steel sheet pile retaining walls and fight to prevent the stone rolling
river.

Two deep pit excavation depth, in order to ensure the integrity of the substrate
and the integrity Pit, excavation loose blasting and smooth blasting u
sing a
combination of methods. From the design of the base to be dredged to stop
when there is 2m loose blasting, while the use of artificial excavation and shallow
hole blasting to design the base, so as to avoid disturbance original geology.

In the found
ation excavation to the design elevation when the 2nd pier foundation
found the cave, so the geological survey department of the rock into the pit of 1,2

Line additional exploration (both for ground penetrating radar geophysical
detection). Additional expl
oration results on the 1st pier foundation basement
geology in good condition, 90% are

Fresh bedrock, only a few small dissolution occurs, overall good rock, rock
mechanical properties meet the design requirements, can serve as a bridge to
stratum. Pier No
. 2 from the basement excavation depth range of 9.7 ~ 17.7m
dissolution large and deep caves were formed columnar down development and
distribution plant and interconnected. 9.7 ~ 17.7m following is a good abutment
bearing stratum. And the 2nd pier foundat
ion front oblique Liuguanghe steep
bedrock canyon downstream along rock joint surface fissure development.


The group held by the owners of the design, construction, supervision, geological
and related technical experts in the construction site will be det
ermined after the
treatment program. Pier No.1 pit gap solution for local high
-
pressure grouting. 2
front 8 × 16m pier foundation would continue to crack down excavation closed
and inversely sloping excavation, excavation cave part in dealing with the C30
concrete after filling to the design base elevation. On the cave for as follows: at
the thinnest excavation cave roof in two 1.2m diameter of the hole into the wall of
the cave clearing tables cave clay and loose gravel, 13m deep below the
basement locatio
n in a downward development of the cave with reinforced
Concrete cover closed, 13m above the cave filled with C30 concrete reality, you
can not use some concrete infill infill using high
-
pressure grouting. Excavation
hole and columnar section of the cave b
y reinforced concrete pile construction,
geological exploration bore hole as both a foundation and anchor piles. The cave
is also interconnected with the cylindrical portion with a steel mesh to form the
whole cave after treatment to ensure that the founda
tion of all in the depth range
9m C30 filled with dense concrete and grouting method. Dealt with by the
geological survey department drilling test approach proved effective, the treated
substrate to meet the design capacity requirements.

Five, pier constru
ction and control

The 1st pier height 73m, 2


Pier height 90m, in such a rigid frame bridge with
high piers is still relatively rare, but the bridge and at scenic spots, on the
appearance of higher quality requirements. Design requirements pier verticalit
y
deviation of not more than 1/1000, the end of pier, pier top position of the center
plane Shen and design deviation of not more than 10mm. Concrete pier for the
quality and appearance of better control, especially the number of investment
funds of $ 100,
000 machining steel pier 12 sets of templates, the specification is
3.0m × 3.0m, 3.Om × 3.5m. Steel formwork specifications and processing
requirements are taken into account in the future construction of the main beam
to be used in the template, so all pi
ers steel template can be used in a hanging
basket full template, both to save money and save time (taking into account the
specifications of the template pier which the horizontal tie beam height).
Concrete pier design numbered C50, pouring using pumping
techniques, in order
to ensure consistent color concrete pier, the entire pier to use the same brand
and label specifications cement.

Construction of the outer frame with steel scaffolding, used in the steel outer
frame main considerations:

(A) take advant
age of the construction unit of existing reusable materials;

(2) the use of steel in the province for the outer frame is a conventional process,
the workers do not need special training, and increased outer frame does not
conflict with other operations can

be interleaved construction jobs faster;

(3) living in the edge of a cliff and pier pier higher altitude, used in the steel outer
frame can reduce the psychological fear of operating personnel, high security;

(4) tie beam frame is steel frame construction
, pier construction in the erection of
the outer frame and the tie beam bracket same specifications so that a relative
reduction of the tie beam construction time;

(5) Because the outer frame on the pier after the modification work is very
convenient;

(6)
when the template altitude install large steel outer frame can be used for the
reinforcement of certain outer frame, while correcting the template of the tube
outer frame is also very convenient;

(7) In order to speed up the construction progress of the st
eel pier to take a long
time to 9m, you need a solid measure of reinforced piers, steel outer frame can
be used as support measures reinforced.

The pier and vertical position control plane

(1) expansion of basic construction of pier reinforcement embedded
released by
the surveyors pier side line, according to the arrangement of piers reinforced
vertical beam reinforcement embedded put a good point, ensuring precise
position reinforced piers (vertical piers by the reinforced steel components for the
three φ2
8 beam tendons, dense layout, spacing is small);

(2) Section pier construction is the key to control the vertical template requires a
large base of first leveling within the template except pull rod outside while using
tubular steel frame and surrounding w
all as a support to ensure that no deviation
concrete pier ;

(3) the expansion of basic tie beam roof and top each channel embedded steel
pier formwork as calibration points, each formwork and after pouring all four
corners of the template using the total
station point positioning checks while in
Canadian large hanging balls and embedded reinforcement calibration points of
the template to adjust the vertical inspection;

(4) to take concrete pouring on the pier permit system should be measured prior
to the p
ouring of inspection reports and templates staff quality inspector

Construction of reinforced inspection report approved by responsible person
pouring, pouring while after the inspection reports issued by the department for
measurement problems immediately

organize relevant personnel to analyze the
causes and propose corrective measures;

(5) on the vertical piers and flat position deviation made more stringent
requirements, the vertical is less than 5/10000, piers center plane position
deviation is less tha
n 5mm.

To protect the pier has been pouring good appearance, especially formulated for
pier protection measures:

(A) In the absence of protective measures in the case of oxygen welding and
welding operations should not be near pier has been poured;

(2)
prohibits throwing objects up and down, all objects that may fall to be cleaned
up to a safe place;

(3) In order to prevent the following health pier water contaminated with plastic
film has been wrapped around the pier pouring;

(4) All holes with tapered
rod block closed.

Carefully organized, strict construction, pier construction has achieved very good
intrinsic quality and the apparent degree, the entire pier Color nearly identical,
vertical maximum deviation of 4/10000, piers center plane position devia
tion less
than 4mm, piers The construction schedule has reached the height of one meter
per day, which looks magnificent, it can be said Liuguanghe bridge is Liuguanghe
has added two scenic landscape.

In addition, the construction of pier construction due
to lack of experience, there
are many areas for improvement,

Such as templates specifications can be further increased to 3.Om × 4.5m, 3.5m
× 4.5m, or even to 3.Om × 6.0m, 3.5m × 6.0m, so that you can further accelerate
the pace of construction pier.

Six,
0, beam segment construction

Continuous rigid frame girder girders No.0 is the largest amount of concrete
pouring party site, prestressed densest, most complex steel

Miscellaneous, dimensions most demanding place. Is continuous rigid frame
construction is
one of the key parts. Liuguanghe bridge concrete block 0

The total amount of soil square 820m3. 0 No. Block finished pouring concrete
pouring impossible once, twice if it is pouring into the bracket construction will be
too big, and finally decided to fini
sh pouring three times. Pouring the first floor
and 1.4m 1.6m webs (not exceeding the extraordinary diaphragm hole that the
entire structure in the human hole at the break, increasing the degree of freedom
of the structure, which will help offset the struc
tural shrinkage stress) . The
second webs pouring 6m high. Third pouring 3.4m webs and roof. Pouring
concrete twice the age of the difference is not

More than 20 days. In the construction of the pier will be conscious pouring pier
height reduction 2Ocm, th
us making the pier junction with block 0

Occlusal surface to avoid the section of mutations at.

Continuous rigid frame bridge construction block 0 of the pier top bracket are
generally embedded or embedded steel corbel beam but considering the
embedded Bai
ley

Steel beams corbels or embedded Bailey has some disadvantages too, one
needs a lot of steel, capital investment NPC wastage. Thick plate steel corbel
need 2Omm about l5t and processing high quality requirements, the applicability
of steel corbels also
poor can not always be used. Bailey embedded beam
method is a method of a waste material, and the specifications Yinbei Lei beam
is fixed, the size of the very poor applicability. Second, the need to adjust the
spacing of vertical reinforcement pier, but L
iuguanghe bridge because vertical
bars are arranged in very dense spacing between the bars is only 6cm,
embedded parts no position. Combined with the characteristics of the bridge
construction in the choice of block No. 0 when using the Universal Rod brack
et
assembly 6m × 6m square steel frame, steel frame base seat in the transverse
beam lines (horizontal tie beam bridge thicker after calculation can be used to
withstand block 0 of the total weight, which is a feature of the bridge). Steel frame
constructi
on on the pier with the pier elevated cater pier construction outer frame.
Pier construction can be carried out after the block 0 template installation,
construction process is continuous and can shorten the construction period, and
the stiffness of the fr
ame, load
-
bearing after the deformation is small, easy to
control the linear block 0, can also reduce stratification When pouring concrete
overlay to the underlying concrete stress generated.

In selected taking into account the concrete mix concrete pumpin
g long distance
(horizontal plus vertical 80m 80m), the amount of concrete pouring

Big, large work surface and other factors retarding superplasticizer admixture
(Zhanjiang admixture plant FDN880 type). Retarding

Time up to 12 hours or more, to ensure the
quality of concrete pouring. 0 Number
block construction is winter, winter construction for large volume

Concrete is particularly detrimental to the concrete curing work must be properly
attentive. Block 0 of exposed roof area, located in the canyon locati
on frequent
air movement, and the third time after pouring concrete to form a whole block 0
empty box structure, easy to distribute the heat of the concrete, so the concrete
conservation work is mainly to prevent excessive temperature difference inside
and

outside large, so keep nurses take the following measures: In all the outer
mold Xiangtie 4cm thick foam for thermal insulation of concrete desert plates,
roof covered with tight sacks watering conservation (the temperature at 5

~ lO

with warm water c
onservation , lO

above normal watering conservation, 5


or less stopped watering conservation), 0, block two ends sealed with plastic
sheeting, the inside temperature is consistently above 10

because it is using
the general watering moist throughout c
uring period of 15 days until the concrete
block 0 outside temperature is less than 10

.

Block 0 Uehara design has a base plate construction with a man hole, according
to the national data reflect the same type of bridge is often found at the hole in
the
human force cracks. After consideration hole right here who has no real
meaning after the inspection, check the position of the hole in the bridge table, on
the floor of block 0 people hole only construction role, if does not have a base
plate helps preven
t cracking, but no impact on the construction ( construction
crane frame and down the middle by the people). So who removed the bottom
plate construction hole, upon inspection after construction on the floor without
cracks.

Seven, the upper box girder cant
ilever construction and construction control

1, Cradle inspection and preload. Liuguanghe bridge hanging basket used for
other bridge used various force components may already be damaged,
deformed, some of the components have been welded heat
-
treated at th
e scene,
along with four hanging basket mixed transport will heap, no prior numbered,
thus causing a hanging basket with difficulties. So a few months before
construction on the upper four Cradle pre
-
assembled (also numbered), and
invited professionals Cra
dle all the force components and welds for ultrasonic
nondestructive testing, especially for all steels while sales for the magnetic
detection of suspicious objects all have the quality to replace them all, to ensure
the reliability of the force. Cradle pr
eload finishing rebar using sand bags
suspended working platform with preload method, each of the main points of
suspension Cradle actual stress points are similar, and observing the Cradle
main persimmon and the deformation of the bottom basket.

2, the up
per block 0 outside unless all 28 segments are all disposable pouring
completed, to ensure that the weight of two cantilever end

Difference in the scope of design, all of the segments in the pouring pouring
when they pay attention to symmetry. Pouring conc
rete using a concrete pump
pumping duct in the middle to both ends of the block No. 0 separation,


Located in the middle of a 90 degree elbow, pouring concrete and based on the
weight difference across the solidification of concrete situations tube
replace
ment. Since Cradle preload is eliminated in inelastic deformation, in the
actual process of settlement deformation pouring small concrete joints better
quality, yet found vertical cracks.

3, continuous rigid frame bridge after the completion of the settlem
ent is
dominated by concrete shrinkage and creep and relaxation of prestressing
caused, from the practical experience, concrete creep and shrinkage than the
theoretical value, in recent years, a large domestic child seat span continuous
rigid frame bridge
subsidence appeared abnormal condition that affects the
appearance of the bridge, this Liuguanghe Bridge across camber setting aside
when awareness reaches span of 1/1000). The high bridge pier construction
control will have to take into account the pier h
eight change on the impact of
construction control, the first is the weight of the upper segment of the pier
compression, the compression value can be computed in the calculation of
compression pier value, can not be taken into account piers weight because

weight pier pier construction in compression when it has happened, in the
construction of block 0 value to be considered in the construction of this
compression in elevation. Followed by temperature
-
induced changes in height
pier construction control effe
cts pier construction season in the lower
temperature is completed, the construction of the upper segment as
temperatures rise, pier expansion will increase the formwork when we must
consider the impact of this part. So we require the construction formwork

provide
formwork segment elevation and the reference point of zero section relative
height, so that you can eliminate the pier height changes.

4, elevation measurements in four stages, before pouring, pouring, the tension
before and after removing hanging

basket. Each stage of the beam segments
that have been pouring good observation, so that the data we provide more
conducive to monitoring units elevation control.

VIII Concluding Remarks

Liuguanghe completion of the bridge, built in the mountains across
the valley to
the river span continuous rigid frame bridge has some positive significance, but
the bridge is also environmentally friendly design of Guizhou Province, containing
one child bridges for highway construction in the mountains How to strengthen
environmental protection has accumulated some experience.



Excerpt from "Chinese Bridge and Structural Engineering Institute of Highway
Society Symposium Proceedings 2001 bridge"