CN106758870B - Unbalanced load monitoring and overall stability judgment method in the construction of bridge cantilever method - Google Patents
Unbalanced load monitoring and overall stability judgment method in the construction of bridge cantilever method Download PDFInfo
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- CN106758870B CN106758870B CN201710005361.9A CN201710005361A CN106758870B CN 106758870 B CN106758870 B CN 106758870B CN 201710005361 A CN201710005361 A CN 201710005361A CN 106758870 B CN106758870 B CN 106758870B
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D21/00—Methods or apparatus specially adapted for erecting or assembling bridges
- E01D21/10—Cantilevered erection
- E01D21/105—Balanced cantilevered erection
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B5/00—Measuring arrangements characterised by the use of mechanical techniques
- G01B5/30—Measuring arrangements characterised by the use of mechanical techniques for measuring the deformation in a solid, e.g. mechanical strain gauge
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K1/00—Details of thermometers not specially adapted for particular types of thermometer
- G01K1/02—Means for indicating or recording specially adapted for thermometers
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- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Bridges Or Land Bridges (AREA)
Abstract
Unbalanced load monitoring and overall stability judgment method in a kind of bridge cantilever method construction of present invention offer, belong to technical field of bridge construction.This method on the bridge pier of temporary consolidation column or continuous rigid frame bridge by installing strain gauge and temperature sensor, according to measurement result of the bridge without temperature and strain in the case of construction loads, the statistical relationship of strain and temperature is obtained using least square method, then, the strain surveyed to the construction stage carries out correction for temperature effect, load strain is obtained, obtains the load imbalance deviation during cantilever construction on this basis.The overall stability of bridge is judged according to load imbalance deviation.The present invention solves the problems, such as that unbalanced load is quantitative in cantilever method bridge construction process, improves the safety of bridge cantilever method construction.
Description
Technical field
The present invention relates to technical field of bridge construction, particularly relates to unbalanced load in a kind of bridge cantilever method construction and monitor
And overall stability judgment method.
Background technology
Cantilever-construction is the important construction method of prestressed concrete continuous beam construction in modern bridge.Due to cantilever
The particularity of construction, in the entire work progress of section cast-in-place, two cantilever end load equilibriums are the passes of site operation control
Key.Symmetrically, it is in order to reduce torque, however, in work progress, it is impossible to accomplish absolute equilibrium that balance, which pours,.《Highway bridge and culvert is applied
Work technical specification》(JTG/T F50-2011) 16.5.4 articles of first item of page 141 is pointed out：Cantilever pouring construction should be symmetrical, flat
The progress of weighing apparatus, the practical uneven deviation of load must not exceed design code value on the cantilever of both ends；When design does not provide, it should not surpass
Cross the 1/4 of beam section dead weight.
It in terms of unbalanced load monitoring, finds by literature search, Liu Jinfeng, Zhou Dongpo, king's Yao exists《City bridge with it is anti-
Flood》2014, (9)：In 200-202《Safety monitoring is carried out to uneven box girder cantilever casting process using electronic sensor》,
The stability that casting process is qualitatively judged using the variation tendency of sensor is disclosed, the defect of this method is can not to judge difference
The difference of the surveyed strain of strain gauge is and not provide the unbalanced amount of construction caused by temperature or caused by load
Change index, therefore, it is impossible to the size of bridge both ends unbalanced load quantitatively be known, to which quantifying for bridge stability can not be carried out
Judge.
Therefore, in the art, it is still desirable to which experiment installation is simple, and rational judgment is steady during capable of carrying out cantilever construction
Qualitative method.
Invention content
Unbalanced load calculating is quantitatively sentenced with stability during the present invention can not carry out cantilever construction for solution is above-mentioned
Disconnected deficiency provides unbalanced load monitoring and overall stability judgment method in a kind of construction of bridge cantilever method.
This method is as follows：
S1：The strain gauge and temperature sensing of the axial strain of measurement column or bridge pier are installed on temporary consolidation column or bridge pier
Device, and strain gauge and temperature sensor using along bridge to midpoint be arranged symmetrically as symmetric points, and temperature sensor with answer
Become meter and is mounted on the same position；
S2：It enables bridge without construction loads, measures bridge strain variation with temperature data, establish strain variation with temperature
Rule；
S3：The initial strain of construction stage strain gauge is measured, then, according to the relationship of strain and temperature, calculates and eliminates temperature
The load strain that degree influences；
S4：Using load strain calculation load imbalance deviation, the overall stability of bridge is judged according to uneven deviation.
Wherein, the axial strain of synchro measure temporary consolidation column or bridge pier and temperature in S2.
In S2 without construction loads in the case of, strain the monitoring time that varies with temperature and be not less than 1 day, sample frequency is not more than
30 minutes/time.
Strain-temperature relation in S2 is calculated using least square method.
The above-mentioned technical proposal of the present invention has the beneficial effect that：
This method is obtained using the strain gauge and temperature sensor of antimere installation on temporary consolidation column or bridge pier by lotus
The axial strain of caused column is carried, load imbalance deviation is thus calculated, to judge the overall stability of bridge.This method
The strain of gained avoids the influence that different column temperatures strain, the unbalanced load for two cantilever ends of calculating that can be quantified, and
Experiment installation is simple, easily operated.
Description of the drawings
Fig. 1 is that unbalanced load monitoring and the monitoring of overall stability judgment method are set during the bridge cantilever method of the present invention is constructed
Standby arrangement schematic diagram；
Fig. 2 is the beam section schematic diagram of bridge cantilever method of embodiment of the present invention construction；
Fig. 3 is A-A sectional views in Fig. 2 of the embodiment of the present invention, and unit is cm in figure；
Fig. 4 is the matched curve of strain gauge and temperature on temporary consolidation column on the left of the embodiment of the present invention；
Fig. 5 is the matched curve of strain gauge and temperature on temporary consolidation column on the right side of the embodiment of the present invention；
Fig. 6 is change curve of the initial strain of the embodiment of the present invention with beam section；
Fig. 7 is change curve of the temperature of the embodiment of the present invention with beam section；
Fig. 8 is change curve of load of the embodiment of the present invention strain with beam section；
Fig. 9 is change curve of the load imbalance deviation of the embodiment of the present invention with beam section.
Wherein：
Construction beam section on the left of 1-；Construction beam section on the right side of 2-；3- has constructed beam section；Temporary consolidation column on the left of 4-；Face on the right side of 5-
When consolidate column；Strain gauge on temporary consolidation column on the left of 6-；Temperature sensor on temporary consolidation column on the left of 7-；Temporary consolidation on the right side of 8-
Strain gauge on column；Temperature sensor on temporary consolidation column on the right side of 9-；10- digital signal acquiring instrument；11- computers.
Specific implementation mode
To keep the technical problem to be solved in the present invention, technical solution and advantage clearer, below in conjunction with attached drawing and tool
Body embodiment is described in detail.
Unbalanced load monitoring and overall stability judgment method in a kind of bridge cantilever method construction of present invention offer.
As shown in Figure 1, in this method, it is symmetrical on 5 sustained height of left side temporary consolidation column 4 and right side temporary consolidation column
Strain gauge 8 on strain gauge 6 and right side temporary consolidation column, measures the axial direction of temporary consolidation column on the temporary consolidation column of position installation left side
Strain；To install left side simultaneously interim solid for the position of strain gauge 8 on strain gauge 6 and right side temporary consolidation column on the temporary consolidation column of left side
Tie on column temperature sensor 9 on temperature sensor 7 and right side temporary consolidation column；When arm beam 3 of having constructed completes basis, continue to pour
Left side construction beam section 1 and right side construction beam section 2 are built, left side temporary consolidation column 4 and right side temporary consolidation column 5 is made to be deformed, point
The strain of temporary consolidation column is not measured by strain gauge 8 on strain gauge 6 on the temporary consolidation column of left side and right side temporary consolidation column；Left side
Strain gauge 6 on temporary consolidation column, temperature sensor 7 on the temporary consolidation column of left side, strain gauge 8, right side on the temporary consolidation column of right side
Temperature sensor 9 connects computer 11 by digital signal acquiring instrument 10 on temporary consolidation column.
In the present invention, the temperature correction being related to is as follows：
When arm beam 3 of having constructed is completed, continue before pouring left side construction beam section 1 and right side construction beam section 2, arm beam of having constructed
In the case of there is no construction loads on 3, while measuring strain and temperature.Strain gauge is measured into strain value and is known as initial strain, it is left
On the temporary consolidation column of side strain gauge 6 measure strain beThe temperature that temperature sensor 7 measures on corresponding left side temporary consolidation column
Degree is T(1)；On the temporary consolidation column of right side strain gauge 8 measure strain beTemperature sensor on corresponding right side temporary consolidation column
9 temperature measured are T(2)。
In the case of there is no construction loads in beam section of having constructed, the initial strain under no-load effect in one day or more and phase are measured
Then the temperature data answered is established to obtain the statistical relationship of initial strain and temperature using linear least square：
After beam section 1 and the right side construction construction of beam section 2 are constructed in left side, for the initial strain of measurement of a certain momentWith
Temperature T(i), then by the load strain stress caused by left side construction beam section 1 and right side construction beam section 2(i)For：
The strain that gained is calculated by formula (2) is that each strain gauge is strained by the load caused by load after temperature adjustmemt.
In the present invention, the derivation according to load strain calculation imbalance deviation is as follows：
On the basis of the construction of beam section of having constructed 3 is completed, continuation pours forward left side construction beam section 1 and right side construction beam section 2, left
The weight of side construction beam section 1 is W1, the weight of right side construction beam section 2 is W2.Left side construction beam section 1 and right side construction beam section 2 are constructed
The initial strain for measuring left and right side temporary consolidation after the completion is respectivelyWithAnd corresponding temperature is T(1)And T(2)。
Then, load strain stress is obtained by formula (2)(1)And ε(2)。
If left side temporary consolidation column and right side temporary consolidation caused by constructing beam section 1 and right side construction beam section 2 due to left side
The axle power of column is respectively F1And F2.The distance between left side temporary consolidation column and right side temporary consolidation column are b, beam section weight of constructing
The distance of position to temporary consolidation column is l.
It can be obtained by B point equalising torques：
F2× b=W2×(l+b)-W1×l；
(3)
It can be obtained by C point equalising torques：
F1× b=W1×(l+b)-W2×l；
(4)
Formula (4) subtracts formula (3) and obtains：
F1-F2=(W1-W2)(2l/b+1)
(5)
Formula (3) is added with formula (4)：
F1+F2=W1+W2
(6)
From the relationship of axle power and strain：
F1=EA ε(1)
(7)
F2=EA ε(2)
(8)
In formula：E is the elasticity modulus of temporary consolidation column, and A is the area of temporary consolidation column section；By formula (7) and formula (8) generation
Enter formula (5) and formula (6), and can be obtained after abbreviation：
In formula, WeFor load imbalance deviation, εeFor imbalance strain ratio.
Since in work progress, strain and temperature are continuous sampling, therefore, the ε in formula (11)(1)And ε(2)It is by each
Initial strain before beam section construction and after construction carries out temperature adjustmemt respectively, then subtracts each other.
Formula (9) shows that the load imbalance deviation for calculating construction beam section can be quantified using the strain on temporary consolidation column.
After obtaining load imbalance deviation, you can according to《Highway bridge and culvert construction technique normalizing》(JTG/T F50-2011) page 141
16.5.4 first item carries out judgement of stability.
Correctness to verify above-mentioned theory and the application in the construction of bridge cantilever method.Below in conjunction with attached drawing and implementation
Example, the present invention will be described in further detail.
Certain variable cross-section prestressed concrete continuous beam is constructed using cantilever-construction.Each bridge pier cantilever-construction
Beam section divides as shown in Figure 2.The long 2.5m of cantilever casting box girder 2# beam sections, the long 3.0m of 3#~5# beam sections, the long 3.5m of 6#~9# beam sections,
The long 4.5m of 10#~13# beam sections, maximum cantilever construct length as 49m.The installation site of strain gauge and temperature sensor such as Fig. 3 institutes
Show.
This experiment strains and temperature monitoring is since after the completion of the construction of 8# (8 ' #) beam section.In 9# beam section initial surveys
Two days without in the case of construction loads strain and temperature, as shown in Figure 4 and Figure 5.Straight line in Fig. 4 and Fig. 5 is exactly least square
The relationship of temperature and strain obtained by method：
By initial strains of 9# (9 ' the #)~12# (12 ' #) before the construction of each beam section and after construction as shown in fig. 6, when corresponding
The temperature at quarter is as shown in fig. 7, the load strain after temperature adjustmemt caused by each beam section is as shown in Figure 8.It can thus be concluded that each beam section is applied
The load imbalance deviation of work, as shown in Figure 9.
As shown in Figure 9, there are load imbalance deviations in cantilever construction process for the bridge.In 9# (9 ' #)~12#
(12 ' #) construction stage, peak load imbalance deviation about 16% or so are less than 1/4, meet code requirement, show the bridge construction
Unbalanced load is preferably controlled in the process, and work progress Bridge is integrally stability.
The above is the preferred embodiment of the present invention, it is noted that for those skilled in the art
For, without departing from the principles of the present invention, several improvements and modifications can also be made, these improvements and modifications
It should be regarded as protection scope of the present invention.
Claims (2)
1. unbalanced load monitoring and overall stability judgment method in a kind of bridge cantilever method construction, it is characterised in that：Specifically
Steps are as follows：
S1：The strain gauge and temperature sensor of the axial strain of measurement column or bridge pier are installed on temporary consolidation column or bridge pier, and
Strain gauge and temperature sensor using along bridge to midpoint be arranged symmetrically as symmetric points, and temperature sensor and strain gauge are pacified
Mounted in the same position；
S2：It enables bridge without construction loads, measures bridge strain variation with temperature data, establish strain variation with temperature rule
Rule；
S3：The initial strain of construction stage strain gauge is measured, then, according to the relationship of strain and temperature, calculates and eliminates temperature shadow
Loud load strain；
S4：Using load strain calculation load imbalance deviation, the overall stability of bridge is judged according to uneven deviation；
The axial strain of synchro measure temporary consolidation column or bridge pier and temperature in the S2；
In the S2 without construction loads in the case of, strain the monitoring time that varies with temperature and be not less than 1 day, sample frequency is not more than
30 minutes/time.
2. unbalanced load monitoring and overall stability judgment method in bridge cantilever method construction according to claim 1,
It is characterized in that：Strain-temperature relation in the S2 is calculated using least square method.
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