CN117744222A - Method for determining state influence rule in construction process of single-inclined-tower cable-stayed bridge - Google Patents
Method for determining state influence rule in construction process of single-inclined-tower cable-stayed bridge Download PDFInfo
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Abstract
The invention discloses a method for determining a state influence rule in a construction process of a single-inclined-tower cable-stayed bridge, and relates to the technical field of cable-stayed bridges; constructing a finite element simulation model of the bridge according to the bridge structure, the geometric parameters, the material properties and the loading conditions of the single-inclined-tower cable-stayed bridge, and carrying out simulation, calculation and analysis on the construction process of the bridge body by combining a construction scheme of multiple tensioning without a bracket; comparing the simulation calculation analysis result of the finite element simulation model of the bridge to the construction process of the bridge body and the state monitoring data of the single-inclined-tower cable-stayed bridge, and analyzing and determining the influence rule of the multiple tensioning construction without a bracket on the stay cable force, the stress-free cable length and the bridge line shape and the stress of the single-inclined-tower cable-stayed bridge; through verification, the method can accurately analyze the influence rule of construction on the single-inclined-tower cable-stayed bridge.
Description
Technical Field
The invention relates to the technical field of cable-stayed bridges, in particular to a method for determining a state influence rule in a construction process of a single-inclined-tower cable-stayed bridge.
Background
With economic development and construction technology innovation, the crossing capability of modern bridges is continuously enhanced. Large span, wider and lighter are the main characteristics of modern bridges. The streamline flat steel box girder single-tower cable-stayed bridge is a preferred form of the modern bridge because of the characteristics of attractive appearance, strong spanning capability, light dead weight, short construction period, good integrity, high rigidity, small influence of construction on environment and the like.
In the construction stage, the structure is a gradual building process, and the component performance, the structural system and the bearing load are dynamically changed. The front and rear hoisting members are connected and then are coupled by stress, and the coupling effect between the structure and the temporary supporting structure exists. The structural design method has great difference with the final structural design state, even accidents can be caused, and personal and property safety and engineering progress speed are seriously influenced.
However, the traditional structural design of the single-inclined-tower cable-stayed bridge usually only considers the analysis of the normal use stage of the structure, only calculates under the design configuration, and does not consider the stress condition in the structural construction process, so that the traditional structural design cannot accurately analyze the influence rule of construction on the single-inclined-tower cable-stayed bridge.
Disclosure of Invention
Aiming at the problem that the traditional structural design cannot accurately analyze the influence rule of construction on the single-inclined-tower cable-stayed bridge, the invention provides a method for determining the state influence rule in the construction process of the single-inclined-tower cable-stayed bridge, which comprises the following steps:
determining bridge structure, geometric parameters, material properties and loading conditions of the single-inclined-tower cable-stayed bridge;
the construction scheme of bracket-free multi-tensioning is adopted for the single-tower cable-stayed bridge, and the state of the single-tower cable-stayed bridge is monitored to obtain state monitoring data of the single-tower cable-stayed bridge;
constructing a finite element simulation model of the bridge according to the bridge structure, the geometric parameters, the material properties and the loading conditions of the single-inclined-tower cable-stayed bridge, and simulating and calculating the construction process of the bridge body according to the finite element simulation model of the bridge and a construction scheme of multiple tensioning without a bracket to obtain simulated calculation data of the construction process of the single-inclined-tower cable-stayed bridge;
and comparing the simulation calculation data of the construction process of the single-inclined-tower cable-stayed bridge with the state monitoring data of the single-inclined-tower cable-stayed bridge, and carrying out optimization cable adjustment on the single-inclined-tower cable-stayed bridge according to the comparison result, thereby determining the influence rule of the shotcrete-free multi-tensioning construction on the stay cable force, the stress-free cable length and the bridge linearity and stress of the single-inclined-tower cable-stayed bridge.
Further, the construction scheme of bracket-free repeated tensioning is adopted for the single-inclined-tower cable-stayed bridge, and the state of the single-inclined-tower cable-stayed bridge is monitored, and the method specifically comprises the following steps:
adopting stay cables to replace temporary brackets for installation construction in the stage of main tower subsection hoisting construction of the single-inclined-tower cable-stayed bridge;
in order to avoid the influence of the construction progress of the main tower due to the construction of the tension cables, a plurality of pairs of main cables are initially intermittently selected to temporarily tie the main tower of the single-inclined-tower cable-stayed bridge, and then the back cables are tensioned;
and after the temporary tensioning is finished, the rest stay cables are intermittently selected for integral tensioning according to construction requirements, the stay cable force of the stay cables is monitored, and the stay cables with the cable force which does not reach the standard are tensioned for the third time, so that the error between the simulation calculation data of the construction process of the single-inclined-tower cable-stayed bridge and the state monitoring data of the single-inclined-tower cable-stayed bridge is within a set range.
Further, the construction scheme of bracket-free repeated tensioning is adopted for the single-inclined-tower cable-stayed bridge, the state of the single-inclined-tower cable-stayed bridge is monitored, and the method further comprises the following steps:
the cable-stayed bridge uses a flexible stay cable, and the sag phenomenon of the stay cable is caused by the dead weight of the flexible stay cable; the sagging degree of the inhaul cable is related to the tension, and the relation is nonlinear; the extension caused by the dead weight of the stay cable and the elastic extension caused by the tension of the cable jointly form the total extension of the cable;
The stay cable is equivalent to a straight rod through equivalent elastic modulus, and only the influence of the dead weight of the stay cable along the vertical direction of the string is considered at the moment;
by establishing a coordinate system and setting up a curve equation of the stay cable, the span bending moment of the stay cable is zero, the length S of the stress cable of the stay cable and the elastic elongation value delta S of the stress cable of the stay cable are calculated respectively, and finally the stress-free length S of the stay cable is obtained 0 The method comprises the steps of carrying out a first treatment on the surface of the The stay cable unstressed length formula is:
wherein f m ＝cosa(ql 0 and/8T) is deflection along the vertical direction of the string line at the mid-span position of the stay cable; q is the weight of the stay cable in unit length; l (L) 0 The chord length of the stay cable; t is the stay cable force; e is the elastic modulus of the stay cable; a is the cross-sectional area of the stay cable; l is the projection length of the stay cable in the x axis, and h is the projection length of the stay cable in the z axis; -Tl 0 EA is the pull under the force of the stay cable.
Further, the finite element simulation model of the bridge is constructed according to the bridge structure, the geometric parameters, the material properties and the loading conditions of the single-inclined-tower cable-stayed bridge, and specifically comprises the following steps:
constructing a finite element simulation model of the bridge by adopting MIDAS/Civil finite element analysis software, discretizing a bridge structure, enabling the model to reach ideal precision and playing a role in guiding construction;
When a model is built, modeling is carried out on the main girder and the main tower by using girder units, and modeling is carried out on the inhaul cable by using truss units; dividing the main girder and the main tower according to the construction sequence to establish a reasonable bridge forming state of the suspension bridge.
Furthermore, the method for simulating, calculating and analyzing the construction process of the bridge body according to the construction scheme of combining the finite element simulation model of the bridge with the bracket-free multi-tensioning specifically comprises the following steps:
the method comprises the steps of analyzing the stress, bending moment and inhaul cable force of a bridge under the second-stage constant load based on a MIDAS/Civil model;
in a specific analysis process, the influence of the structural dead weight, the lane load and the combined load on the stress state and the deformation characteristic of the bridge structure is focused.
Further, the simulation calculation data of the construction process of the single-inclined-tower cable-stayed bridge and the state monitoring data of the single-inclined-tower cable-stayed bridge are compared, and the single-inclined-tower cable-stayed bridge is optimized and adjusted according to the comparison result, so that the influence of the multiple tensioning construction without a bracket on the stay cable force, the non-stress cable length and the bridge linearity and stress of the single-inclined-tower cable-stayed bridge is determined, and the method specifically comprises the following steps:
comparing the actually measured cable force value with the designed cable force value, wherein the stretching of the inhaul cable achieves the expected effect, is basically consistent with the designed cable force, and meets the requirement of a bracket-free construction method;
The whole bridge structure can meet the design requirement through tension adjustment of the stay cable; the main purpose of the integral tensioning is to enable the stay cable and the bridge structure to reach a preset tension state so as to ensure the stability and the safety of the bridge;
comparing stay cable force data measured during integral tensioning with stay cable force data calculated by an MIDAS/Civil model, wherein integral trend accords with a design cable force change rule;
in the second-stage constant load, the actual measurement cable force value of the stay cable is relatively close to the theoretical value through cable adjustment, and the error is less than 5%.
Further, the simulation calculation data of the construction process of the single-inclined-tower cable-stayed bridge and the state monitoring data of the single-inclined-tower cable-stayed bridge are compared, and the single-inclined-tower cable-stayed bridge is optimized and adjusted according to the comparison result, so that the influence of the multiple tensioning construction without a bracket on the stay cable force, the non-stress cable length, the bridge linearity and the stress of the single-inclined-tower cable-stayed bridge is determined, and the method further comprises the following steps:
determining the length of the unstressed cable of the cable-stayed bridge comprises determining the geometric shape of the stayed cable, considering the characteristics of the cable material, analyzing the load condition of the bridge and establishing a stress balance equation; solving by solving an equation, and determining the length of the cable-stayed bridge when the cable-stayed bridge is not subjected to any load; calculating the length of the unstressed cable is important to ensuring the design rationality, stability and reliability of the cable-stayed bridge;
The length of the non-stressed cables of the single-inclined-tower cable-stayed bridge is calculated and compared with the theoretical non-stressed cable length, the non-stressed cable lengths of the two main bridges have the same change trend, and the shorter the main cable and the back cable are, the closer the main tower is, the shorter the non-stressed cable length is, and as the stay cable bears larger tension at the main tower, the tension gradually decreases along with the extension to the bridge deck; the length of the stay cable is shortened, so that the length of the unstressed cable of the stay cable which is closer to the main tower is relatively shorter; the error between the calculated value and the theoretical value of the stress-free cable length is small; therefore, the bridge formation state of the two main bridges reaches an ideal state.
Further, the simulation calculation data of the construction process of the single-inclined-tower cable-stayed bridge and the state monitoring data of the single-inclined-tower cable-stayed bridge are compared, and the single-inclined-tower cable-stayed bridge is optimized and adjusted according to the comparison result, so that the influence of the multiple tensioning construction without a bracket on the stay cable force, the non-stress cable length, the bridge linearity and the stress of the single-inclined-tower cable-stayed bridge is determined, and the method further comprises the following steps:
arranging measuring points at the positions of the piles, and measuring the relative elevation of each position at different stages; the relative elevation of each position before cable adjustment, during cable adjustment for the second time and cable adjustment for the third time is compared with a theoretical value;
Comparing the line type change condition of each stage of the two main bridges with the change of the inhaul cable force, and knowing that the actually measured cable force is larger than the designed cable force during temporary tensioning, so that the line type of the bridge is higher than the designed line type; after the cable force is adjusted by twice tensioning, the cable force of the inhaul cable is continuously optimized, and the line type of the bridge is gradually close to the design line; in a bridge forming state, errors of actual measurement linearity and design linearity of the bridge are controlled within a reasonable range, and the construction scheme of multiple tensioning without the support plays a final role in bridge construction.
Further, the simulation calculation data of the construction process of the single-inclined-tower cable-stayed bridge and the state monitoring data of the single-inclined-tower cable-stayed bridge are compared, and the single-inclined-tower cable-stayed bridge is optimized and adjusted according to the comparison result, so that the influence of the multiple tensioning construction without a bracket on the stay cable force, the non-stress cable length, the bridge linearity and the stress of the single-inclined-tower cable-stayed bridge is determined, and the method further comprises the following steps:
stress changes of the upper edge and the lower edge of the bridge are controlled through cable force optimization, cable force distribution is optimized, and stress balance of each component in the bridge structure is achieved; the reasonable cable force distribution can lead all parts of the bridge to be stressed uniformly, and avoid overlarge stress concentration, thereby reducing the fatigue damage and the damage risk of the bridge;
Selecting a plurality of sections from two main bridge sections of the single-inclined-tower cable-stayed bridge, measuring the stress of the upper surface and the lower surface of each section to form stress curves during integral tensioning and bridge formation, and comparing the actually measured stress curves with theoretical stress curves derived from an MIDAS/Civil model;
the change value of the girder stress at each construction stage is consistent with the rule of the theoretical change value no matter in integral stretching or bridge formation, and the error between the theoretical value and the actual measured value of the bridge stress is controlled within a reasonable range by adjusting the cable force.
Compared with the prior art, the method for determining the state influence rule in the construction process of the single-inclined-tower cable-stayed bridge has the beneficial effects that:
the invention inputs the geometric parameters, material properties and loading conditions of the bridge based on MIDAS/Civil analysis software, and generates a detailed numerical model; the model considers each component part of the bridge, such as a main girder, a tower and a stay cable; the sensor and the measuring equipment collect data including bridge stress, bridge line type, inhaul cable force and the like; next, the invention compares the model data with the actual measurement data, and finds that the actual measurement cable force is consistent with the design cable force when the bridge is temporarily tensioned by comparing the cable force of the stay cable of the bridge, but the error value between the two is obviously increased when the bridge is integrally tensioned; after the third cable adjustment, the cable force value of the stay cable in the bridge formation reaches a design value, and the length of the unstressed cable in the bridge formation is consistent with the design value; by comparing bridge line types, the invention discovers that the change trend of the measured data in three stages of cable adjustment before cable adjustment, cable adjustment for the second time and cable adjustment for the third time is influenced by cable force change, and the error between the measured value and the theoretical value is finally controlled in a more satisfactory range along with the optimization of cable force; in addition, by comparing bridge stresses, the invention discovers that under the whole stretching and second-stage constant load stage, the maximum value of the upper edge stress and the lower edge stress appears on the section at 172.5m, and the variation trend of the measured data is consistent with that of the theoretical data. Therefore, the method can accurately analyze the influence rule of construction on the single-inclined-tower cable-stayed bridge.
Drawings
Fig. 1 is a schematic plan layout diagram of a main bridge of a eternal river super bridge provided by an embodiment of the invention;
FIG. 2 is a schematic diagram of a finite element model of a space of a eternal river super bridge provided by the embodiment of the invention;
fig. 3 is a schematic diagram of a main bridge stress cloud of a eternal river super bridge provided by an embodiment of the invention;
fig. 4 is a schematic diagram of a line-shaped cloud of a main bridge of a eternal river super bridge provided by the embodiment of the invention;
FIG. 5 is a schematic diagram of the stress of a stay cable of a eternal river super bridge provided by the embodiment of the invention;
FIG. 6 is a schematic diagram of temporary north bridge cable tension of a eternal river super bridge provided by the embodiment of the invention;
fig. 7 is a schematic diagram of temporary tensioning south bridge cable force of a eternal river super bridge according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of the first overall north bridge cable tension of the eternal river super bridge provided by the embodiment of the invention;
fig. 9 is a schematic diagram of a first integral tensile south bridge cable force of a eternal river super bridge provided by an embodiment of the invention;
FIG. 10 is a schematic diagram of a second overall north bridge cable tension of a eternal river super bridge provided by an embodiment of the present invention;
FIG. 11 is a schematic diagram of a second overall tensile south bridge cable force of a eternal river super bridge provided by an embodiment of the present invention;
FIG. 12 is a schematic diagram of a north bridge non-stressed cable length of a Yongding river super bridge according to an embodiment of the present invention;
Fig. 13 is a schematic diagram of a length of a stress-free cable of a south bridge of a eternal river super bridge according to an embodiment of the present invention;
FIG. 14 is a schematic diagram of a relative elevation of a Northbridge of a Yongding river super bridge according to an embodiment of the present invention;
FIG. 15 is a schematic diagram of a relative elevation of a south bridge of a eternal river super bridge according to an embodiment of the present invention;
FIG. 16 is a schematic diagram of the upper edge stress of the Northbridge of a Yongding river super bridge according to an embodiment of the present invention;
FIG. 17 is a schematic diagram of the north bridge lower edge stress of a eternal river super bridge according to an embodiment of the present invention;
FIG. 18 is a schematic diagram of upper edge stress of a permanent river super bridge south bridge according to an embodiment of the present invention;
fig. 19 is a schematic diagram of stress at the lower edge of the south bridge of the eternal river super bridge according to an embodiment of the present invention.
Detailed Description
Embodiments of the present invention are further described below with reference to fig. 1-19. The following examples are only for more clearly illustrating the technical aspects of the present invention, and are not intended to limit the scope of the present invention.
Example 1: the invention provides a method for determining a state influence rule in a construction process of a single-inclined-tower cable-stayed bridge, which comprises the following steps: determining bridge structure, geometric parameters, material properties and loading conditions of the single-inclined-tower cable-stayed bridge; the construction scheme of bracket-free multi-tensioning is adopted for the single-tower cable-stayed bridge, and the state of the single-tower cable-stayed bridge is monitored to obtain state monitoring data of the single-tower cable-stayed bridge; constructing a finite element simulation model of the bridge according to the bridge structure, the geometric parameters, the material properties and the loading conditions of the single-inclined-tower cable-stayed bridge, and simulating and calculating the construction process of the bridge body according to the finite element simulation model of the bridge and a construction scheme of multiple tensioning without a bracket to obtain simulated calculation data of the construction process of the single-inclined-tower cable-stayed bridge; and comparing simulation calculation data of the construction process of the single-inclined-tower cable-stayed bridge with state monitoring data of the single-inclined-tower cable-stayed bridge, and optimizing and adjusting the single-inclined-tower cable-stayed bridge according to comparison results, so as to determine the influence of the bracket-free multi-tensioning construction on the stay cable force, the stress-free cable length and the bridge linearity and stress of the single-inclined-tower cable-stayed bridge.
In this embodiment, the construction scheme of multiple tensioning without a bracket is adopted for the single-tower cable-stayed bridge, and the monitoring of the state of the single-tower cable-stayed bridge specifically includes: adopting stay cables to replace temporary brackets for installation construction in the stage of main tower subsection hoisting construction of the single-inclined-tower cable-stayed bridge; in order to avoid the influence of the construction progress of the main tower due to the construction of the tension cables, a plurality of pairs of main cables are initially intermittently selected to temporarily tie the main tower of the single-inclined-tower cable-stayed bridge, and then the back cables are tensioned; and after the temporary tensioning is finished, the rest stay cables are intermittently selected for integral tensioning according to construction requirements, the stay cable force of the stay cables is monitored, and the stay cables with the cable force which does not reach the standard are tensioned for the third time, so that the error between the simulation calculation data of the construction process of the single-inclined-tower cable-stayed bridge and the state monitoring data of the single-inclined-tower cable-stayed bridge is within a set range.
In this embodiment, the construction scheme of multiple tensioning without a bracket is adopted for the single-tower cable-stayed bridge, and the monitoring of the state of the single-tower cable-stayed bridge further includes: the cable-stayed bridge uses a flexible stay cable, and the sag phenomenon of the stay cable is caused by the dead weight of the flexible stay cable; the sagging degree of the inhaul cable is related to the tension, and the relation is nonlinear; the extension caused by the dead weight of the stay cable and the elastic extension caused by the tension of the cable jointly form the total extension of the cable; the stay cable is equivalent to a straight rod through equivalent elastic modulus, and only the influence of the dead weight of the stay cable along the vertical direction of the string is considered at the moment; by establishing a coordinate system and setting up a curve equation of the stay cable, the span bending moment of the stay cable is zero, the length S of the stress cable of the stay cable and the elastic elongation value delta S of the stress cable of the stay cable are calculated respectively, and finally the stress-free length S of the stay cable is obtained 0 The method comprises the steps of carrying out a first treatment on the surface of the The stay cable unstressed length formula is:
wherein f m ＝cosa(ql 0 and/8T) is deflection along the vertical direction of the string line at the mid-span position of the stay cable; q is the weight of the stay cable in unit length; l (L) 0 The chord length of the stay cable; t is the stay cable force; e is the elastic modulus of the stay cable; a is the cross-sectional area of the stay cable; l is the projection length of the stay cable in the x axis, and h is the projection length of the stay cable in the z axis; -Tl 0 EA is the pull under the force of the stay cable.
In this embodiment, the constructing a finite element simulation model of the bridge according to the bridge structure, the geometric parameters, the material properties and the loading conditions of the single-inclined-tower cable-stayed bridge specifically includes: constructing a finite element simulation model of the bridge by adopting MIDAS/Civil finite element analysis software, discretizing a bridge structure, enabling the model to reach ideal precision and playing a role in guiding construction; when a model is built, modeling is carried out on the main girder and the main tower by using girder units, and modeling is carried out on the inhaul cable by using truss units; dividing the main girder and the main tower according to the construction sequence to establish a reasonable bridge forming state of the suspension bridge.
In this embodiment, the simulating and calculating the construction process of the bridge body according to the finite element simulation model of the bridge and the construction scheme of multiple tensioning without a bracket specifically includes: the method comprises the steps of analyzing the stress, bending moment and inhaul cable force of a bridge under the second-stage constant load based on a MIDAS/Civil model; in a specific analysis process, the influence of the structural dead weight, the lane load and the combined load on the stress state and the deformation characteristic of the bridge structure is focused.
In this embodiment, the comparing the analog calculation data of the construction process of the single-inclined-tower cable-stayed bridge with the state monitoring data of the single-inclined-tower cable-stayed bridge optimizes the cable-adjusting of the single-inclined-tower cable-stayed bridge according to the comparison result, so as to determine the influence of the multiple tensioning construction without a bracket on the stay cable force, the stress-free cable length and the bridge linearity and stress of the single-inclined-tower cable-stayed bridge, and specifically includes: comparing the actually measured cable force value with the designed cable force value, wherein the stretching of the inhaul cable achieves the expected effect, is basically consistent with the designed cable force, and meets the requirement of a bracket-free construction method; the whole bridge structure can meet the design requirement through tension adjustment of the stay cable; the main purpose of the integral tensioning is to enable the stay cable and the bridge structure to reach a preset tension state so as to ensure the stability and the safety of the bridge; comparing stay cable force data measured during integral tensioning with stay cable force data calculated by an MIDAS/Civil model, wherein integral trend accords with a design cable force change rule; in the second-stage constant load, the actual measurement cable force value of the stay cable is relatively close to the theoretical value through cable adjustment, and the error is less than 5%.
In this embodiment, the simulation calculation data of the construction process of the single-inclined-tower cable-stayed bridge and the state monitoring data of the single-inclined-tower cable-stayed bridge are compared, and the single-inclined-tower cable-stayed bridge is optimized according to the comparison result, so as to determine the influence of the multiple tensioning construction without a bracket on the stay cable force, the non-stress cable length and the bridge linearity and stress of the single-inclined-tower cable-stayed bridge, and the method further includes: determining the length of the unstressed cable of the cable-stayed bridge comprises determining the geometric shape of the stayed cable, considering the characteristics of the cable material, analyzing the load condition of the bridge and establishing a stress balance equation; solving by solving an equation, and determining the length of the cable-stayed bridge when the cable-stayed bridge is not subjected to any load; calculating the length of the unstressed cable is important to ensuring the design rationality, stability and reliability of the cable-stayed bridge; the length of the non-stressed cables of the single-inclined-tower cable-stayed bridge is calculated and compared with the theoretical non-stressed cable length, the non-stressed cable lengths of the two main bridges have the same change trend, and the shorter the main cable and the back cable are, the closer the main tower is, the shorter the non-stressed cable length is, and as the stay cable bears larger tension at the main tower, the tension gradually decreases along with the extension to the bridge deck; the length of the stay cable is shortened, so that the length of the unstressed cable of the stay cable which is closer to the main tower is relatively shorter; the error between the calculated value and the theoretical value of the stress-free cable length is small; therefore, the bridge formation state of the two main bridges reaches an ideal state.
In this embodiment, the simulation calculation data of the construction process of the single-inclined-tower cable-stayed bridge and the state monitoring data of the single-inclined-tower cable-stayed bridge are compared, and the single-inclined-tower cable-stayed bridge is optimized according to the comparison result, so as to determine the influence of the multiple tensioning construction without a bracket on the stay cable force, the non-stress cable length and the bridge linearity and stress of the single-inclined-tower cable-stayed bridge, and the method further includes: arranging measuring points at the positions of the piles, and measuring the relative elevation of each position at different stages; the relative elevation of each position before cable adjustment, during cable adjustment for the second time and cable adjustment for the third time is compared with a theoretical value; comparing the line type change condition of each stage of the two main bridges with the change of the inhaul cable force, and knowing that the actually measured cable force is larger than the designed cable force during temporary tensioning, so that the line type of the bridge is higher than the designed line type; after the cable force is adjusted by twice tensioning, the cable force of the inhaul cable is continuously optimized, and the line type of the bridge is gradually close to the design line; in a bridge forming state, errors of actual measurement linearity and design linearity of the bridge are controlled within a reasonable range, and the construction scheme of multiple tensioning without the support plays a final role in bridge construction.
In this embodiment, the simulation calculation data of the construction process of the single-inclined-tower cable-stayed bridge and the state monitoring data of the single-inclined-tower cable-stayed bridge are compared, and the single-inclined-tower cable-stayed bridge is optimized according to the comparison result, so as to determine the influence of the multiple tensioning construction without a bracket on the stay cable force, the non-stress cable length and the bridge linearity and stress of the single-inclined-tower cable-stayed bridge, and the method further includes: stress changes of the upper edge and the lower edge of the bridge are controlled through cable force optimization, cable force distribution is optimized, and stress balance of each component in the bridge structure is achieved; the reasonable cable force distribution can lead all parts of the bridge to be stressed uniformly, and avoid overlarge stress concentration, thereby reducing the fatigue damage and the damage risk of the bridge; selecting a plurality of sections from two main bridge sections of the single-inclined-tower cable-stayed bridge, measuring the stress of the upper surface and the lower surface of each section to form stress curves during integral tensioning and bridge formation, and comparing the actually measured stress curves with theoretical stress curves derived from an MIDAS/Civil model; the change value of the girder stress at each construction stage is consistent with the rule of the theoretical change value no matter in integral stretching or bridge formation, and the error between the theoretical value and the actual measured value of the bridge stress is controlled within a reasonable range by adjusting the cable force.
Example 2: in this embodiment, the gallery Yongding river bridge is taken as an example to further describe the embodiment 1 of the present invention.
The gallery permanent river super-large bridge belongs to an ultra-wide steel box girder single-tower cable-stayed bridge, adopts a tower girder concreting self-anchored multi-time hyperstatic structure, has various and complex construction steps, is greatly influenced by the sectional length, the construction temperature, the cable tensioning sequence and the force value, and greatly increases the difficulty of precision control. The project main tower creatively applies the bracket-free process construction, in order to ensure the linearity accuracy of the main tower and meet the final bridge formation state of design requirements, a finite element model of the construction process is established and subjected to simulation calculation analysis, a comparison result is fed back to construction technicians, the size of a temporary guy cable and the size of a tensioning force are reasonably recommended and optimized for the next-stage construction, the hoisting and tensioning of each section of main tower are strictly controlled in the construction process, the project safety and the construction period are ensured, good economic benefits are created, and the bridge construction and operation processes can be safer and more efficient.
1 engineering overview
The eternal river extra-large bridge spans the eternal river north small twist and the front south Wei Nian, the total length of the bridge is 2047 meters, and the width of the bridge is 47m. The bridge is an approach bridge and a main bridge respectively, and 15 links are formed in total of the full bridge: and fifth and twelfth bridges are main bridges, and cable-stayed bridges are adopted to span the main river channel. The main bridge is positioned on a straight line (initial pile number: K0+835, final pile number: K1+1035), the bridge floor has a transverse slope of 1.5% in both directions and a longitudinal slope of 0.3%, and the main bridge is collectively called a north bridge in the embodiment; the plane of the second main bridge is positioned on a straight line (initial pile number is K1+1795, end pile number is K1+1995), the transverse slope of the bridge deck is 1.5% in two directions, the longitudinal slope is-0.4%, and the second main bridge is called as a south bridge in the embodiment; the abutment is arranged radially. The two main bridges have the same structural system, and are all in the form of single-inclined-tower cable-stayed bridges, and tower beams are fixedly connected and pier beams are separated. The main tower is a steel tower, and the main beam is a steel box beam. The main span is provided with 16 pairs of stay cables, the braiding is arranged, and the lower lifting point is positioned at the outer side of the main span overhaul channel; the side span is provided with 12 pairs of back ropes which are arranged in a fan shape, and the lower hanging point is positioned at the central dividing belt of the side span. Rectangular hollow pier columns are adopted as the lower pier columns of the main tower, column piers are adopted as the rest of piers, and bored piles are adopted as the foundation form. And a special-shaped decorative plate is arranged at the main tower position of the cable-stayed bridge.
The ultra-wide steel box girder single-tower cable-stayed bridge adopts a tower girder consolidation self-anchored multi-hyperstatic structure, and a plurality of complex steps are involved in the construction process. Because the main tower has the characteristics of ultra-wide cross section and combination welding variability, the accuracy of main tower construction has challenges. In order to reduce engineering cost and shorten construction period, the project adopts a bracket-free process construction. In order to ensure the bearing capacity and design line type of the main tower, a finite element method is used for carrying out whole-process construction simulation analysis, and a scheme for adding temporary inhaul cables is determined according to a calculation result. By the scheme, the stress and displacement of the main tower in the construction process can be controlled, and any section can meet the requirements of bearing capacity and linetype. The bracket-free construction scheme provides theoretical support and guarantee for the safe construction of the main tower.
2 construction process
The project adopts a bracket-free multi-tensioning construction scheme, namely, a temporary bracket is replaced by a stay cable to carry out installation construction in a main tower subsection hoisting construction stage, meanwhile, in order to avoid the influence of the construction progress of the main tower due to the tension cable construction, 5 pairs of main cables Z1, Z6, Z11, Z14 and Z16 (south bridge: Z1, Z6, Z11 and Z16) are initially intermittently selected to carry out temporary drawknot on the main tower, then back cables B1, B5 and B12 (south bridge: B6, B8 and B12) are tensioned, after the temporary tensioning is finished, the rest stay cables are intermittently selected to carry out integral tensioning according to the construction requirement, the cable force of the stay cables is monitored, and the third tensioning is carried out on the stay cables with the cable force which does not reach the standard.
Flexible stay cables are often used for cable-stayed bridges, and the sag phenomenon of the stay cables can be caused by the dead weight of the flexible stay cables. The sagging degree of the stay is related to the tension, and the relationship thereof is nonlinear. The elongation caused by the dead weight of the stay cable and the elastic elongation caused by the tension of the cable form the total elongation of the cable.
The stay cable can be equivalently a straight rod through equivalent elastic modulus, and only the influence of the dead weight of the stay cable along the vertical direction of the string is considered at the moment. By establishing a coordinate system and setting up a curve equation of the stay cable, the span bending moment of the stay cable is zero, the length S of the stress cable of the stay cable and the elastic elongation value delta S of the stress cable of the stay cable are calculated respectively, and finally the stress-free length S of the stay cable is obtained 0 The method comprises the steps of carrying out a first treatment on the surface of the The stay cable unstressed length formula is:
wherein f m ＝cosa(ql 0 and/8T) is deflection along the vertical direction of the string line at the mid-span position of the stay cable; q is the weight of the stay cable in unit length; l (L) 0 The chord length of the stay cable; t is the stay cable force; e is the elastic modulus of the stay cable; a is the cross-sectional area of the stay cable; l is the projection length of the stay cable in the x axis, and h is the projection length of the stay cable in the z axis; -Tl 0 EA is the pull under the force of the stay cable. When the cable force is determined, the stress-free cable length can be calculated.
3 building finite element model
In order to establish a finite element model of the eternal river super bridge and carry out analysis application, MIDAS/Civil finite element analysis software is adopted in the embodiment. The finite element model can be basically consistent with the actual construction result only if the precision is enough, and the calculated stress and deformation result is basically consistent with the actual construction result.
When the model is built, the girder and the main tower are modeled by using girder units, and the inhaul cable is modeled by using truss units. Dividing the main girder and the main tower according to the construction sequence to establish a reasonable bridge forming state of the suspension bridge. Through the model establishment and discretization, the embodiment can more accurately perform the stress analysis of the eternal river super bridge and obtain the result conforming to the actual construction condition. The finite element structure model is built up to 1306 units and 832 nodes.
And analyzing the stress, bending moment and inhaul cable force of the bridge under the second-stage constant load based on the MIDAS/Civil model. In a specific analysis process, the embodiment focuses on the influence of the structural dead weight, the lane load and the combined load on the stress state and the deformation characteristic of the bridge structure.
4. Construction simulation calculation and analysis
4.1 Cable force of stay cable
Because the project adopts a bracket-free construction method, temporary tensioning is needed to ensure the normal construction of the main tower. The measured cable force values are compared with the designed cable force values, as shown in fig. 6 and 7. The stretching of the inhaul cable achieves the expected effect, is basically consistent with the design cable force, and meets the requirements of a bracket-free construction method.
In the construction process of the cable-stayed bridge, integral tensioning is one of the key steps. Through carrying out the pulling force adjustment to the stay cable, ensure that whole bridge structure can reach the design requirement. The main purpose of the integral tensioning is to enable the stay cable and the bridge structure to reach a preset tension state so as to ensure the stability and the safety of the bridge.
The stay cable force data measured during overall tensioning are compared with the stay cable force data calculated by the MIDAS/Civil model, as shown in fig. 8 and 9. It can be found that the north bridge guy cable force is in a descending trend from the main tower as a center to the two sides, and the cable force is greatly reduced at the B5 position. The overall trend accords with the design rope force change rule. In the construction process, the maximum cable force of the north bridge and the south bridge is all present on the Z11-shaped stay cable, the maximum cable force of the north bridge is 1512kN, the maximum cable force of the south bridge is 1505KN, the minimum cable force of the north bridge is present on the Z13-shaped stay cable, the minimum cable force of the north bridge is 291KN, and the minimum cable force of the south bridge is 246KN, which is the Z14-shaped stay cable.
In the second-stage constant load, the forces of the north and south bridge cables are all in an ascending trend with the main tower as the center to change to the two sides, but the forces of the stay cables Z13-Z16 positioned at the edge are obviously reduced. Through final cable adjusting, the measured cable force value of the stay cable is relatively close to the theoretical value, and the error is less than 5%.
4.2 stress free cable Length
Determining the unstressed cable length of a cable-stayed bridge is a critical step in the design process. This step involves a number of aspects including geometry determination of the stay cable, consideration of characteristics of the cable material, analysis of the load conditions of the bridge, and establishment of stress balance equations. The length of the cable-stayed bridge when no load is applied can be accurately determined by solving the equation. Accurate calculation of the unstressed cable length is critical to ensuring the design rationality, stability and reliability of the cable-stayed bridge. Therefore, when designing a cable-stayed bridge, the parameter must be carefully considered and accurately calculated to ensure that the performance and the safety of the bridge are effectively ensured.
The length of the cable-stayed unstressed cable of the north-south bridge is calculated and compared with the theoretical unstressed cable, as shown in figures 12 and 13. It can be seen that the length of the non-stress cables of the two main bridges has the same change trend, and the length of the non-stress cables of the main tower is shorter as the main cable and the back cable are closer to the main tower, and the stay cable bears larger tension at the main tower, so that the tension gradually decreases along with the extension to the bridge deck. This shortens the length of the stay cable, resulting in a relatively short unstressed cable length of the stay cable closer to the main tower. And the error maximum value of the calculated value and the theoretical value of the north bridge stress-free cable length is 0.165mm, the error maximum value of the south bridge is 0.153mm, and the error values are smaller, so that the bridge formation state of the two main bridges can be considered to reach an ideal state.
4.3 Main bridge alignment
And arranging measuring points at the positions of the piles, and measuring the relative elevation of each position at different stages. The relative heights of the positions before cable adjustment, during cable adjustment for the second time and cable adjustment for the third time are compared with theoretical values respectively, as shown in fig. 14 and 15. It is known that the line shape of the north bridge is matched with the theoretical line shape before the pile No. 914 before the cable is adjusted, but the deviation from the theoretical line shape is larger and larger after that, and the measured relative elevation curve reaches the peak value of 0.723m when the pile No. 1002 is arranged. The measured data trend of the south bridge is opposite to that of the north bridge, and the measured relative elevation of the south bridge reaches a peak value of 0.802m when the pile number 1798 is arranged; in the second cable adjusting process, the error of the measured value and the theoretical value is obviously improved compared with that before cable adjusting, the maximum value of the measured relative elevation of the north bridge appears at the position of the 1020 # pile, and the value is 0.614m. The maximum value of the measured relative elevation of the south bridge appears at the position of a 1822 # pile, and the value is 0.891m; and thirdly, rope adjustment, wherein the line type of the bridge is completely matched with the design line type, and the maximum value of the measured relative elevation of the north bridge appears at the position of a 1026 # pile, and the value is 0.6m. The maximum value of the measured relative elevation of the south bridge appears at the position of a 1789 pile, and the value is 0.803m.
Comparing the line type change condition of each stage of the two main bridges with the change of the inhaul cable force, the fact that the actually measured cable force is larger than the designed cable force when the two main bridges are temporarily tensioned can be known, and the line type of the bridge is higher than the designed line type. After the cable force is adjusted by twice tensioning, the cable force of the inhaul cable is continuously optimized, and the line type of the bridge is gradually close to the design line type. In a bridge forming state, errors of actual measurement linearity and design linearity of the bridge are controlled within a reasonable range, and the construction scheme of multiple tensioning without the support plays a good effect on bridge construction finally.
4.4 Main bridge stress
The stress changes of the upper edge and the lower edge of the bridge are controlled through cable force optimization, so that the distribution of cable force is optimized, and the stress balance of each component in the bridge structure can be realized. The reasonable cable force distribution can lead all parts of the bridge to be stressed uniformly, and avoid overlarge stress concentration, thereby reducing the fatigue damage and the damage risk of the bridge.
In this embodiment, 9 sections are selected from the main bridge sections of the north and south bridges, and stresses on the upper and lower surfaces of each section are measured and consolidated into stress curves during overall stretching and bridging, and the actual measured stress curves are compared with theoretical stress curves derived from the MIDAS/Civil model, as shown in fig. 6 to 9, since the stress states of the north and south bridges are similar, only the north bridges are analyzed.
The upper and lower edge stresses of the two main bridges reach the maximum value at the section of 172.5m both during integral stretching and bridge forming, and the maximum values of the upper edge stresses of the north bridge during integral stretching and bridge forming are respectively-36.1 MPa and-60.8 MPa. The maximum values of the stress of the lower edge of the south bridge during integral stretching and bridging are respectively 37.2MPa and 65.1MPa. It can be seen that the change value of the girder stress at each construction stage is consistent with the law of the theoretical change value, and the error between the theoretical value and the actual measured value of the bridge stress is controlled within a reasonable range by adjusting the cable force.
In a comprehensive view, compared with the prior art, the method for determining the state influence rule in the construction process of the single-inclined-tower cable-stayed bridge has the following beneficial effects:
the invention takes the construction project of the eternal river super bridge in the gallery city as the background, based on MIDAS/Civil analysis software, inputs the geometric parameters, material properties and loading conditions of the bridge, and generates a detailed numerical model. The model considers each component of the bridge, such as a girder, a tower, a stay cable and the like. The sensor and the measuring equipment collect data including bridge stress, bridge line type, inhaul cable force and the like; next, the invention compares the model data with the actual measurement data, and finds that the actual measurement cable force is matched with the design cable force when the cable is temporarily stretched by comparing the cable forces of the stay cables of the north and south bridges, but the error value between the two cable forces is obviously increased when the cable is wholly stretched; after the third cable adjustment, the cable force value of the stay cable in the bridge formation reaches a design value, and the length of the unstressed cable in the bridge formation is consistent with the design value; by comparing bridge line types, the invention discovers that the change trend of the measured data in three stages of cable adjustment before cable adjustment, cable adjustment for the second time and cable adjustment for the third time is influenced by cable force change, and the error between the measured value and the theoretical value is finally controlled in a more satisfactory range along with the optimization of cable force; in addition, by comparing the stresses of the south bridge and the north bridge, the invention discovers that under the integral stretching and the second-stage constant load stage, the maximum value of the upper edge stress and the lower edge stress appears on the section at 172.5m, and the variation trend of the measured data is consistent with that of the theoretical data. Provides guiding significance for similar engineering construction.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
Claims (9)
1. A method for determining a state influence rule in a construction process of a single-inclined-tower cable-stayed bridge is characterized by comprising the following steps of:
determining bridge structure, geometric parameters, material properties and loading conditions of the single-inclined-tower cable-stayed bridge;
the construction scheme of bracket-free multi-tensioning is adopted for the single-tower cable-stayed bridge, and the state of the single-tower cable-stayed bridge is monitored to obtain state monitoring data of the single-tower cable-stayed bridge;
constructing a finite element simulation model of the bridge according to the bridge structure, the geometric parameters, the material properties and the loading conditions of the single-inclined-tower cable-stayed bridge, and simulating and calculating the construction process of the bridge body according to the finite element simulation model of the bridge and a construction scheme of multiple tensioning without a bracket to obtain simulated calculation data of the construction process of the single-inclined-tower cable-stayed bridge;
And comparing the simulation calculation data of the construction process of the single-inclined-tower cable-stayed bridge with the state monitoring data of the single-inclined-tower cable-stayed bridge, and carrying out optimization cable adjustment on the single-inclined-tower cable-stayed bridge according to the comparison result, thereby determining the influence rule of the shotcrete-free multi-tensioning construction on the stay cable force, the stress-free cable length and the bridge linearity and stress of the single-inclined-tower cable-stayed bridge.
2. The method for determining the state influence law in the construction process of the single-tower cable-stayed bridge according to claim 1, wherein the construction scheme of multiple tensioning without a bracket is adopted for the single-tower cable-stayed bridge, and the state of the single-tower cable-stayed bridge is monitored, and the method specifically comprises the following steps:
adopting stay cables to replace temporary brackets for installation construction in the stage of main tower subsection hoisting construction of the single-inclined-tower cable-stayed bridge;
in order to avoid the influence of the construction progress of the main tower due to the construction of the tension cables, a plurality of pairs of main cables are initially intermittently selected to temporarily tie the main tower of the single-inclined-tower cable-stayed bridge, and then the back cables are tensioned;
and after the temporary tensioning is finished, the rest stay cables are intermittently selected for integral tensioning according to construction requirements, the stay cable force of the stay cables is monitored, and the stay cables with the cable force which does not reach the standard are tensioned for the third time, so that the error between the simulation calculation data of the construction process of the single-inclined-tower cable-stayed bridge and the state monitoring data of the single-inclined-tower cable-stayed bridge is within a set range.
3. The method for determining a state influence rule in a construction process of a single-tower cable-stayed bridge according to claim 2, wherein the construction scheme of multiple tensioning without a bracket is adopted for the single-tower cable-stayed bridge, and the method for monitoring the state of the single-tower cable-stayed bridge further comprises:
the cable-stayed bridge uses a flexible stay cable, and the sag phenomenon of the stay cable is caused by the dead weight of the flexible stay cable; the sagging degree of the inhaul cable is related to the tension, and the relation is nonlinear; the extension caused by the dead weight of the stay cable and the elastic extension caused by the tension of the cable jointly form the total extension of the cable;
the stay cable is equivalent to a straight rod through equivalent elastic modulus, and only the influence of the dead weight of the stay cable along the vertical direction of the string is considered at the moment;
by establishing a coordinate system and setting up a curve equation of the stay cable, the span bending moment of the stay cable is zero, the length S of the stress cable of the stay cable and the elastic elongation value delta S of the stress cable of the stay cable are calculated respectively, and finally the stress-free length S of the stay cable is obtained 0 The method comprises the steps of carrying out a first treatment on the surface of the The stay cable unstressed length formula is:
wherein f m ＝cosa(ql 0 and/8T) is deflection along the vertical direction of the string line at the mid-span position of the stay cable; q is the weight of the stay cable in unit length; l (L) 0 The chord length of the stay cable; t is the stay cable force; e is the elastic modulus of the stay cable; a is the cross-sectional area of the stay cable; l is the projection length of the stay cable in the x axis, and h is the projection length of the stay cable in the z axis; -Tl 0 EA is the pull under the force of the stay cable.
4. The method for determining the state influence law in the construction process of the single-inclined-tower cable-stayed bridge according to claim 1, wherein the finite element simulation model of the bridge is constructed according to the bridge structure, the geometric parameters, the material properties and the loading conditions of the single-inclined-tower cable-stayed bridge, and specifically comprises the following steps:
constructing a finite element simulation model of the bridge by adopting MIDAS/Civil finite element analysis software, discretizing a bridge structure, enabling the model to reach ideal precision and playing a role in guiding construction;
when a model is built, modeling is carried out on the main girder and the main tower by using girder units, and modeling is carried out on the inhaul cable by using truss units; dividing the main girder and the main tower according to the construction sequence to establish a reasonable bridge forming state of the suspension bridge.
5. The method for determining the state influence law in the construction process of the single-inclined-tower cable-stayed bridge according to claim 1, wherein the construction process of the bridge body is simulated and calculated according to a finite element simulation model of the bridge combined with a construction scheme of bracket-free multi-tensioning, and the method specifically comprises the following steps:
the method comprises the steps of analyzing the stress, bending moment and inhaul cable force of a bridge under the second-stage constant load based on a MIDAS/Civil model;
In a specific analysis process, the influence of the structural dead weight, the lane load and the combined load on the stress state and the deformation characteristic of the bridge structure is focused.
6. The method for determining a state influence rule in a construction process of a single-inclined-tower cable-stayed bridge according to claim 1, wherein the comparison of the simulation calculation data of the construction process of the single-inclined-tower cable-stayed bridge and the state monitoring data of the single-inclined-tower cable-stayed bridge optimizes the cable-adjusting of the single-inclined-tower cable-stayed bridge according to the comparison result so as to determine the influence of the bracket-free multi-tensioning construction on the stay cable force, the stress-free cable length and the bridge linearity and stress of the single-inclined-tower cable-stayed bridge, and the method specifically comprises the following steps:
comparing the actually measured cable force value with the designed cable force value, wherein the stretching of the inhaul cable achieves the expected effect, is basically consistent with the designed cable force, and meets the requirement of a bracket-free construction method;
the whole bridge structure can meet the design requirement through tension adjustment of the stay cable; the main purpose of the integral tensioning is to enable the stay cable and the bridge structure to reach a preset tension state so as to ensure the stability and the safety of the bridge;
comparing stay cable force data measured during integral tensioning with stay cable force data calculated by an MIDAS/Civil model, wherein integral trend accords with a design cable force change rule;
In the second-stage constant load, the actual measurement cable force value of the stay cable is relatively close to the theoretical value through cable adjustment, and the error is less than 5%.
7. The method for determining a law of influence of a state in a construction process of a single-inclined-tower cable-stayed bridge according to claim 6, wherein the comparing the analog calculation data of the construction process of the single-inclined-tower cable-stayed bridge with the state monitoring data of the single-inclined-tower cable-stayed bridge optimizes the single-inclined-tower cable-stayed bridge according to the comparison result, thereby determining the influence of the multiple tensioning construction without a bracket on the stay cable force, the non-stress cable length and the bridge linearity and stress of the single-inclined-tower cable-stayed bridge, further comprising:
determining the length of the unstressed cable of the cable-stayed bridge comprises determining the geometric shape of the stayed cable, considering the characteristics of the cable material, analyzing the load condition of the bridge and establishing a stress balance equation; solving by solving an equation, and determining the length of the cable-stayed bridge when the cable-stayed bridge is not subjected to any load; calculating the length of the unstressed cable is important to ensuring the design rationality, stability and reliability of the cable-stayed bridge;
the length of the non-stressed cables of the single-inclined-tower cable-stayed bridge is calculated and compared with the theoretical non-stressed cable length, the non-stressed cable lengths of the two main bridges have the same change trend, and the shorter the main cable and the back cable are, the closer the main tower is, the shorter the non-stressed cable length is, and as the stay cable bears larger tension at the main tower, the tension gradually decreases along with the extension to the bridge deck; the length of the stay cable is shortened, so that the length of the unstressed cable of the stay cable which is closer to the main tower is relatively shorter; the error between the calculated value and the theoretical value of the stress-free cable length is small; therefore, the bridge formation state of the two main bridges reaches an ideal state.
8. The method for determining a law of influence of a state in a construction process of a single-inclined-tower cable-stayed bridge according to claim 7, wherein the comparing the analog calculation data of the construction process of the single-inclined-tower cable-stayed bridge with the state monitoring data of the single-inclined-tower cable-stayed bridge optimizes the single-inclined-tower cable-stayed bridge according to the comparison result, thereby determining the influence of the multiple tensioning construction without a bracket on the stay cable force, the non-stress cable length and the bridge linearity and stress of the single-inclined-tower cable-stayed bridge, further comprising:
arranging measuring points at the positions of the piles, and measuring the relative elevation of each position at different stages; the relative elevation of each position before cable adjustment, during cable adjustment for the second time and cable adjustment for the third time is compared with a theoretical value;
comparing the line type change condition of each stage of the two main bridges with the change of the inhaul cable force, and knowing that the actually measured cable force is larger than the designed cable force during temporary tensioning, so that the line type of the bridge is higher than the designed line type; after the cable force is adjusted by twice tensioning, the cable force of the inhaul cable is continuously optimized, and the line type of the bridge is gradually close to the design line; in a bridge forming state, errors of actual measurement linearity and design linearity of the bridge are controlled within a reasonable range, and the construction scheme of multiple tensioning without the support plays a final role in bridge construction.
9. The method for determining a law of influence of a state in a construction process of a single-inclined-tower cable-stayed bridge according to claim 8, wherein the comparing the analog calculation data of the construction process of the single-inclined-tower cable-stayed bridge with the state monitoring data of the single-inclined-tower cable-stayed bridge optimizes the single-inclined-tower cable-stayed bridge according to the comparison result, thereby determining the influence of the multiple tensioning construction without a bracket on the stay cable force, the non-stress cable length and the bridge linearity and stress of the single-inclined-tower cable-stayed bridge, further comprising:
stress changes of the upper edge and the lower edge of the bridge are controlled through cable force optimization, cable force distribution is optimized, and stress balance of each component in the bridge structure is achieved; the reasonable cable force distribution can lead all parts of the bridge to be stressed uniformly, and avoid overlarge stress concentration, thereby reducing the fatigue damage and the damage risk of the bridge;
selecting a plurality of sections from two main bridge sections of the single-inclined-tower cable-stayed bridge, measuring the stress of the upper surface and the lower surface of each section to form stress curves during integral tensioning and bridge formation, and comparing the actually measured stress curves with theoretical stress curves derived from an MIDAS/Civil model;
the change value of the girder stress at each construction stage is consistent with the rule of the theoretical change value no matter in integral stretching or bridge formation, and the error between the theoretical value and the actual measured value of the bridge stress is controlled within a reasonable range by adjusting the cable force.
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