CN105113422B - Back-stayed balance continuous beam cast-in-situ section construction method - Google Patents
Back-stayed balance continuous beam cast-in-situ section construction method Download PDFInfo
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- CN105113422B CN105113422B CN201510594591.4A CN201510594591A CN105113422B CN 105113422 B CN105113422 B CN 105113422B CN 201510594591 A CN201510594591 A CN 201510594591A CN 105113422 B CN105113422 B CN 105113422B
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Abstract
The invention discloses a back-stayed balance continuous beam cast-in-situ section construction method which comprises the following steps: computing a bending moment generated to a pier body by a cast-in-situ section construction dead load according to construction materials and construction environments as well as applied force required for balancing the bending moment generated to the pier body by the cast-in-situ section construction; preparing materials, and pre-setting ducts and pre-burying iron castings on the pier body and anchored rock; anchoring the first end of a steel strand on the rock, anchoring the second end of the steel strand to the top of the pier body, and tensioning according to the force; installing a pedestal, erecting a bracket, and laying a bottom die; carrying out pre-pressing inspection, and then carrying out cast-in-situ section construction; folding and tensioning side spans; and then removing the steel strand, thereby finishing the construction. The back-stayed balance continuous beam cast-in-situ section construction method disclosed by the invention cancels plenty of balance weights on the back of the cast-in-situ section, greatly reduces the workload, reduces the cost expense, and eliminates the high-risk hidden dangers caused by the high-risk process of the balance weights.
Description
Technical field
The present invention relates to a kind of construction techniques, more particularly to a kind of back of the body evens up weighing apparatus continuous beam cast-in-place section construction method.
Background technology
Prestressed concrete continuous beam has economic and practical, aesthetic in appearance, structure durable, and operation maintenance expense is low, knot
The advantages of structure span is big, it is widely used at home and abroad at present.And in the method for construction of prestressed concrete continuous beam, extensively make
It is Hanging Basket cantilever pouring with most economical method.Before continuous beam closes up, it is necessary to pour 4～12m in border pier (abutment pier)
Cast-in-place straightway (end portion of beam).
The casting method of Cast-in-Situ Segment is mainly Support Method, calf support method at present.Support Method is because different using timbering material
It is divided into bowl button support, universal stand, concrete filled steel tube column support, reinforced concrete upright column support.Support Method need to be with greatly
The material of amount and artificial, and as the increase support stability of height there is also test, when support height is more than 28m, support
Safety become very fragile, cost expenses are big, economically very unreasonable.Therefore calf support arises at the historic moment, and bracket support
The moment of flexure that frame is produced to bridge pier, people are balanced using the method for symmetric cow legs counterweight.As often Cast-in-Situ Segment quality is very big so that
Weight mass is also very big, during counterweight, virtually increased security risk again.
The content of the invention
The purpose of the present invention is that to solve the above problems and provides a kind of back of the body and even up weighing apparatus continuous beam cast-in-place section construction
Method.
The present invention is achieved through the following technical solutions above-mentioned purpose：
A kind of back of the body evens up weighing apparatus continuous beam cast-in-place section construction method, comprises the following steps：
(1) moment M that cast-in-place section construction static load produces to pier shaft is calculated and for balancing according to construction material and construction environment
Power F applied required for the moment of flexure that cast-in-place section construction is produced to pier shaft：
M=M1+M2,
F=(M/H)/cos α
In formula：M1For the moment of flexure that Cast-in-Situ Segment armored concrete weight is produced to pier shaft；
M2For the moment of flexure that calf support support and template weight are produced to pier shaft；
H is the height for planning applying power position to cushion cap；
α is the angle of cut of the steel strand wires to horizontal plane；
(2) prepare material, and duct and embedded iron parts are preset on pier shaft and anchoring rock；
(3) first end of steel strand wires is anchored on rock, the second end of steel strand wires is anchored in into the top of pier shaft, and is pressed
Tensioning is carried out according to power F；
(4) mounting bracket, and support is set up, lay bed die；
(5) cast-in-place section construction is carried out by after carrying out precompressed inspection, after end bay closes up tensioning, steel strand wires are released, it is complete
Into construction.
Further, also include in step (1) that maximum crack ω is calculated in inspectionmax
In formula:
аcrFor member stress characteristic coefficient, 1.9 are taken
Longitudinal tensile regular reinforcement strain nonuniformity coefficient, ψ between ψ cracks<0.2, ψ is taken when 0.2>1 is taken when 1；
σsLoad Combination calculates longitudinal tensile reinforcement stresses
ESThe elastic modelling quantity of tensile region reinforcing bar；
csThe distance of outermost layer longitudinal tensile reinforcing bar to tensile region base, by design value and 20mm<cs<65mm；
ρteThe longitudinal direction effectively tension reinforcement ratio of reinforcement, armored concrete value is As/(bh0)；
AteEffective tension concrete section area
AsThe tensile region area of reinforcement；
ApTensile region deformed bar area；
deqThe equivalent diameter of tensile region longitudinal reinforcement；
diThe nominal diameter of the i-th kind of longitudinal reinforcement in tensile region；
niThe radical of the i-th kind of longitudinal reinforcement in tensile region；
viThe bonding characteristic coefficient of the i-th kind of longitudinal reinforcement in tensile region,《Code for design of concrete structures》(GB50010-
2010) table 7.1.2-2 chooses；
Take limit crack ωlimIf, ωmax≤ωlim, then meet construction requirement；
If ωmax≥ωlim, then should multi-stage loading in work progress or after finishing.
Preferably, the limit crack is ω according to reinforced concrete structure three-level crack secondary environment valuelim=
0.20mm。
Specifically, in step (2) and step (3), steel strand wires include spiral, steel with the attachment means of anchoring rock
Frame, bridle iron and I-steel, the lower end of the spiral pass through the bridle iron and the I-steel and the anchoring rock
It is fixedly connected, the steel bracket is arranged between the surface of the I-steel and the anchoring rock, the first of the steel strand wires
End is fixedly connected with the I-steel.
Specifically, in step (2) and step (3) attachment means of steel strand wires and pier shaft include pre-buried pvc pipe, billet,
Jack and two work anchorages, the pre-buried pvc pipe are arranged in the bent cap of the pier shaft, the outer wall of the pre-buried pvc pipe
Spiral bar is provided with, the billet is arranged on the end face of the pre-buried pvc pipe, and the jack is arranged on two work
Between anchorage, and positioned at the outer surface of the billet, the second end of the steel strand wires is through the work anchorage, described very heavy
Top and the pre-buried pvc pipe are connected with the pier shaft.
Further, before carrying out steel strand tension in step (3), the theoretical displacement S at the top of pier shaft need to be calculated：
S=(3l-L) PL2/(6Bs)
In formula：S is pier displacement amount；
Height of the l for measuring point to pier bottom；
Height of the L for pier bottom to bracing wire position；
P horizontal pulls；
BsFor pier flexural rigidity of section, reference during calculating《Code for design of concrete structures》(GB50010-2010)7.2.3
Chapters and sections 7.2.3-1 formula are calculated；
ESThe elastic modelling quantity of tensile region reinforcing bar；
AsThe tensile region area of reinforcement；
h0The effective depth in section；
Longitudinal tensile regular reinforcement strain nonuniformity coefficient, ψ between ψ cracks<0.2, ψ is taken when 0.2>1 is taken when 1；
аEReinforcing bar elastic modelling quantity is conversion coefficient with the ratio of modulus of elasticity of concrete：ES/EC；
ρ longitudinal steel ratio values, armored concrete value are As/(bh0)；
γfThe ratio of tensile region flange section product and web net sectional area, square-section takes 0；
When steel strand tension is carried out, the displacement at the top of pier shaft, the theoretical displacement of comparison and actual displacement is detected, works as actual bit
When moving more than displacement is calculated, pushing tow tensioning should be stopped immediately, and checked.
Preferably, in step (5), the release method of steel strand wires is identical with the method for taking off anchor.
The beneficial effects of the present invention is：
The present invention back of the body is evened up weighing apparatus continuous beam cast-in-place section construction method and has advantages below：
(1) pier displacement of pier top unbalanced moment generation is solved, has been evaded pier shaft long-time and there is moment of flexure, pier shaft
The problem of meeting crackle；
(2) evade the security risk of counterweight method, save a large amount of labor-material-machine costs；
(3) for high pier, a large amount of labor-material-machine costs are saved relative to Support Method；
(4) cancel the substantial amounts of counterweight of Cast-in-Situ Segment back, greatly reduce workload, reduce cost payout, and eliminate and match somebody with somebody
The high-risk hidden danger that the high-risk operation in Chong Zhe roads is brought.
Description of the drawings
Fig. 1 is the schematic diagram that the back of the body of the present invention evens up weighing apparatus continuous beam cast-in-place section construction method；
Fig. 2 is the structural representation of steel strand wires of the present invention and the attachment means of the anchoring rock；
Fig. 3 is the structural representation of steel strand wires of the present invention and the attachment means of the pier shaft.
Specific embodiment
The invention will be further described with reference to the accompanying drawings and examples：
So that Sichuan Province Dadu River Huang Jinping Hydropower Station reservoir area cross a river gives up the United Nations General Assembly's bridge as an example, there is provided a specific embodiment.
House the United Nations General Assembly bridge situation is confirmed according to specific environment first, i.e.,：Spanning be designed as 40+ (63+115+63m continuous beams)+2 ×
20 bridge span structures, pier shaft 20 be border pier, side be 40m " T " beam, opposite side be continuous beam 63m end bays, the high 40.6m of pier, friction
Pile foundation, 4 Φ 1.8m drilled piles, 7.5 × 7.5 × 3m cushion caps, 20 5 × 2.2m of section of pier shaft, Cast-in-Situ Segment floor space are 4.38
× 5m, while confirming material requested, specifically see the table below：
According to construction environment and material list, the cast-in-place section construction method is comprised the following steps：
(1) moment M and be flat that cast-in-place section construction static load produced to pier shaft 20 is calculated according to construction material and construction environment
Power F applied required for the moment of flexure that weighing apparatus cast-in-place section construction is produced to pier shaft 20：
The gravity G of timberWood=(120 × 0.02+3.5) × 0.54 × 10=31.86KN
The gravity G of steelSteel=(15 × 94.2+36 × 41.9975+250 × 4.0135)/100=39.3KN
Moment M 2=(31.86+39.3) × (4.38/2)=155.8KN m that pier shaft 20 is produced
The moment of flexure that Cast-in-Situ Segment armored concrete is produced to pier shaft 20
M1=1.54 × 14.6479 × 26 × 1.54/2+14.6497 × 1.34 × 26 × (1.54+1.34/2)+15.8 ×
26 × (1.54+1.34+1.5 × (6.955/14.615))=3055.8KN m
Total moment M M1+M2=155.8+3055.8=3211.6KN m that static load is produced to pier shaft 20
Power F=(the M/H)/cos α applied required for the moment of flexure produced to pier shaft 20 for balance cast-in-place section construction=
(3211.6/40.5)/cos0.6=79.3KN
And to maximum crack width ωmaxCalculated：
As=43102.7mm2
Ate=5500000.0mm2
ρte=As/Ate=0.008 takes ρte=0.010
V=1.0
deq=28.00mm
ho=2136mm
σs=Mq/(0.87×ho×As)=40.10MPa
ftk=2.39MPa
ψ=1.1-0.65 × ftk/ρte/σsk=-2.774 take ψ=0.200
C=50mm
αcr=1.9
ωmax=αcr×ψ×σs×(1.9×c+0.08×deq/ρte)/Es=0.02mm
ωmax<ωlim=0.2,79.3KN jacking force can be applied to pier shaft 20.
(2) prepare material, and duct and embedded iron parts are preset on pier shaft 20 and anchoring rock 10；
(3) as shown in figure 1, the first end of steel strand wires 30 is anchored on rock 10, the second end of steel strand wires 30 is anchored
In the top of pier shaft 20, and tensioning is carried out according to power F=97.3KN；Theoretical displacement S at the top of pier shaft 20 need to be carried out simultaneously
Calculate：
Bending stiffness Bs is calculated first
Pier shaft C40 modulus of elasticity of concrete：Ec=32500N/mm2
HRB400 reinforcing bar bullet moulds：Es=200000N/mm2
аE=ES/EC=6.153846154, the Φ 28HRB400 areas of reinforcement：As=86205mm2
h0=2136mm, ρ=0.008, ψ=1.1-0.65 × ftk/ρte/σsk=-2.774, take ψ=0.200
Displacement is calculated again
S=(3l-L) PL2/(6Bs)
L ≈ L, P=79300N, L=40600mm；
S=PL3/(3Bs)=16.4mm
S=16.4mm, and 20 top displacement amount of pier shaft is measured for 15mm, less than value of calculation, thus it is speculated that do not consider for calculating
The factor or urging action error of 20 stiff skeleton of pier shaft and reinforcement.
(4) according to scheme mounting bracket and setting up support, and bed die is laid, then precompressed is tested, whether actual installation
Meet computation schemes, 3055KNm moments of flexure are produced in precompressed according to concrete and be simulated pressure testing, calculate homogeneous reactor ballast 883KN,
When 100% design ballast is depressed into, total powerstation monitoring pier displacement is 16mm.Substantially it is consistent with pushing tow displacement.
(5) steel strand wires 30 can be released according to the method for taking off anchor after end bay closes up tensioning, completes construction, forbid directly to cut
Disconnected bracing wire causes security incident.
As shown in Fig. 2 steel strand wires 30 include spiral 21, steel bracket 22, steel with the attachment means of anchoring rock 10
Seat 24 and I-steel 23, the lower end of spiral 21 pass through bridle iron 24 and I-steel 23 to be fixedly connected with anchoring rock 10, steel
Support 22 is arranged between the surface of I-steel 23 and anchoring rock 10, and the first end of steel strand wires 30 is fixed with I-steel 23 and connected
Connect.
As shown in figure 3, steel strand wires 30 include pre-buried pvc pipe 12, billet 11, jack 16 with the attachment means of pier shaft 20
With two work anchorages 14, pre-buried pvc pipe 12 is arranged in the bent cap of pier shaft 20, and the outer wall of pre-buried pvc pipe 12 is provided with spiral
Muscle 13, billet 11 are arranged on the end face of pre-buried pvc pipe 12, and jack 16 is arranged between two work anchorages 14, and is located at
The outer surface of billet 11, the second end of steel strand wires 30 is through work anchorage 14, jack 16 and pre-buried pvc pipe 12 and pier shaft 20
Connection.
Technical scheme is not limited to the restriction of above-mentioned specific embodiment, and every technology according to the present invention scheme is done
The technology deformation for going out, each falls within protection scope of the present invention.
Claims (7)
1. a kind of back of the body evens up weighing apparatus continuous beam cast-in-place section construction method, it is characterised in that comprise the following steps：
(1) moment M that cast-in-place section construction static load produces to pier shaft and cast-in-place for balancing is calculated according to construction material and construction environment
Power F applied required for the moment of flexure that section construction is produced to pier shaft：
M=M1+M2,
F=(M/H)/cos α
In formula：M1For the moment of flexure that Cast-in-Situ Segment armored concrete weight is produced to pier shaft；
M2For the moment of flexure that calf support support and template weight are produced to pier shaft；
H is the height for planning applying power position to cushion cap；
α is the angle of cut of the steel strand wires to horizontal plane；
(2) prepare material, and duct and embedded iron parts are preset on pier shaft and anchoring rock；
(3) first end of steel strand wires is anchored on rock, the second end of steel strand wires is anchored in into the top of pier shaft, and according to power
F carries out tensioning；
(4) mounting bracket, and support is set up, lay bed die；
(5) cast-in-place section construction is carried out by after carrying out precompressed inspection, after end bay closes up tensioning, steel strand wires are released, complete to apply
Work.
2. the back of the body according to claim 1 evens up weighing apparatus continuous beam cast-in-place section construction method, it is characterised in that in step (1) also
Including：Maximum crack ω is calculated in inspectionmax
In formula:
αcrFor member stress characteristic coefficient；
Longitudinal tensile regular reinforcement strain nonuniformity coefficient between ψ cracks；
σsLoad Combination calculates longitudinal tensile reinforcement stresses；
ESThe elastic modelling quantity of tensile region reinforcing bar；
csThe distance of outermost layer longitudinal tensile reinforcing bar to tensile region base；
ρteThe longitudinal direction effectively tension reinforcement ratio of reinforcement；
Take limit crack ωlimIf, ωmax≤ωlim, then meet construction requirement；
If ωmax≥ωlim, then should multi-stage loading in work progress or after finishing.
3. the back of the body according to claim 2 evens up weighing apparatus continuous beam cast-in-place section construction method, it is characterised in that the limit crack
It is ω according to reinforced concrete structure three-level crack secondary environment valuelim=0.20mm.
4. the back of the body according to claim 1 evens up weighing apparatus continuous beam cast-in-place section construction method, it is characterised in that step (2) and step
Suddenly in (3), steel strand wires include spiral, steel bracket, bridle iron and I-steel, the screw thread with the attachment means of anchoring rock
The lower end of reinforcing bar passes through the bridle iron and the I-steel to be fixedly connected with the anchoring rock, and the steel bracket is arranged on institute
State between the surface of I-steel and the anchoring rock, the first end of the steel strand wires is fixedly connected with the I-steel.
5. the back of the body according to claim 1 evens up weighing apparatus continuous beam cast-in-place section construction method, it is characterised in that step (2) and step
Suddenly in (3), steel strand wires include pre-buried pvc pipe, billet, jack and two work anchorages with the attachment means of pier shaft, described pre-
Bury pvc pipe to be arranged in the bent cap of the pier shaft, the outer wall of the pre-buried pvc pipe is provided with spiral bar, and the billet is arranged
In the end face of the pre-buried pvc pipe, the jack is arranged between two work anchorages, and positioned at the billet
Outer surface, the second end of the steel strand wires pass through the work anchorage, the jack and the pre-buried pvc pipe and the pier shaft
Connection.
6. the back of the body according to claim 1 evens up weighing apparatus continuous beam cast-in-place section construction method, it is characterised in that in step (3)
Before carrying out steel strand tension, the theoretical displacement S at the top of pier shaft need to be calculated：
S=(3l-L) PL2/(6Bs)
In formula：S is pier displacement amount；
Height of the L for pier bottom to bracing wire position；
BsFor pier flexural rigidity of section；
When steel strand tension is carried out, detect the displacement at the top of pier shaft, the theoretical displacement of comparison and actual displacement, when actual displacement it is big
When displacement is calculated, pushing tow tensioning should be stopped immediately, and checked.
7. the back of the body according to claim 1 evens up weighing apparatus continuous beam cast-in-place section construction method, it is characterised in that in step (5)
The release method of steel strand wires is identical with the method for taking off anchor.
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| CN201510594591.4A CN105113422B (en) | 2015-09-17 | 2015-09-17 | Back-stayed balance continuous beam cast-in-situ section construction method |
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|---|---|---|---|
| CN201510594591.4A CN105113422B (en) | 2015-09-17 | 2015-09-17 | Back-stayed balance continuous beam cast-in-situ section construction method |
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| CN105113422B true CN105113422B (en) | 2017-03-22 |
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| CN108193605A (en) * | 2018-02-24 | 2018-06-22 | 中交路桥建设有限公司 | No. 0 block bracket prepressing structure of continuous beam bridge pier in water |
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| CN203160134U (en) * | 2013-03-25 | 2013-08-28 | 中交路桥建设有限公司 | Short cantilever support suitable for side span cast-in-situ section construction |
| CN203923922U (en) * | 2014-07-11 | 2014-11-05 | 四川川交路桥有限责任公司 | The box type girder cast-in-place bracing frame that possesses whole traverse moving function |
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Inventor after: Yin Chengqian Inventor after: Liu Taifu Inventor after: Tan Jun Inventor after: Yuan Dapeng Inventor after: Chen Hong Inventor after: Wang Yuhang Inventor after: Tang Pan Inventor before: Yin Chengqian Inventor before: Yuan Dapeng Inventor before: Chen Hong Inventor before: Tan Jun Inventor before: Wang Yuhang Inventor before: Tang Pan |
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