CN-122020806-A - Large-span arch bridge constant load and long-term effect bending moment amplitude modulation method based on axial compression compensation

CN122020806ACN 122020806 ACN122020806 ACN 122020806ACN-122020806-A

Abstract

The invention discloses a method for amplitude modulation of a constant load and long-term effect bending moment of a large-span arch bridge based on axial compression compensation, which is applied to the technical field of bridge engineering. The method comprises the steps of establishing a large-span arch bridge rod system unit model according to design parameters, respectively calculating arch crown internal force caused by constant load, shrinkage and creep, solving arch crown axial compression quantity caused by constant load, temperature, shrinkage and creep, calculating initial axial compression compensation quantity of a closure, calculating total internal force under the action of ten years creep of a structure after the initial axial compression compensation quantity of the closure is applied, judging whether the ratio of the initial constant load internal force is smaller than a threshold value, if the ratio is larger than or equal to the threshold value, iterating calculation until the ratio is smaller than the threshold value, and outputting final closure length compensation quantity for guiding construction closure. According to the invention, the compensation quantity is preset in the closure stage, so that the axial compression effect caused by constant load, temperature, shrinkage and creep is effectively counteracted, the bridge bending moment is reduced, and the real pure pressure of the large-span arch bridge is realized.

Inventors

ZHOU YIN
LUO CHAO
ZHOU JIANTING
LIU JIANJUN
YANG JIAN
TANG QIZHI
XIN JINGZHOU
ZHANG HONG
MEN PENGFEI

Assignees

重庆交通大学
贵州省交通规划勘察设计研究院股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260213

Claims (7)

1. The method for amplitude modulation of the constant load and long-term effect bending moment of the large-span arch bridge based on axial compression compensation is characterized by comprising the following steps of: s1, building a bridge rod system unit model of the large-span arch bridge according to design parameters of the large-span arch bridge; s2, respectively calculating the arch ring vault internal force caused by constant load, shrinkage and creep 、 And ; S3, respectively solving the axial compression quantity of the arch ring caused by constant load, temperature, shrinkage and creep 、、 And ; S4, calculating initial axial compression compensation quantity of the closure ; S5, calculating total internal force under the action of ten years of structural creep after the initial axial compression compensation quantity of the closure is applied ; S6, judging And an initial constant load internal force If the ratio of (2) is less than or equal to the threshold, and if so, recalculate the amount of axial compression caused by creep Updating the axial compression compensation amount Iterative calculation is carried out until the ratio is smaller than a threshold value; s7, outputting the final closure length compensation quantity Is used for guiding construction closure.
2. The method for amplitude modulation of constant load and long-term effect bending moment of a large span arch bridge based on axial compression compensation according to claim 1, wherein in S2, finite elements are adopted to calculate the forces in arch crown caused by constant load, shrinkage and creep 、 And 。
3. The method for amplitude modulation of constant load and long-term effect bending moment of a large-span arch bridge based on axial compression compensation according to claim 1, wherein the method is characterized in that the axial compression amount of an arch ring caused by constant load is solved The method comprises the following steps: ; In the formula, Is the cross-sectional area of the arch rib, For the dome area, Is the angle between the tangent line of the arch axis and the horizontal line, In order to design the strain, For the curvature of the dome, Is the span length.
4. The method for amplitude modulation of constant load and long-term effect bending moment of a large span arch bridge based on axial compression compensation according to claim 1, wherein the temperature induced arch ring axial compression is solved The method comprises the following steps: ; In the formula, Is the difference between the temperature at the time of closure and the average temperature, As a result of the coefficient of expansion of the material, Is the span length.
5. The method for amplitude modulation of constant load and long-term effect bending moment of a large span arch bridge based on axial compression compensation according to claim 1, wherein the amount of axial compression of an arch ring caused by shrinkage is solved The method comprises the following steps: ; and calculating the axial compression amount caused by shrinkage according to the proportion of shrinkage to the bending moment of the constant load arch rib.
6. The method for amplitude modulation of constant load and long-term effect bending moment of a large-span arch bridge based on axial compression compensation according to claim 1, wherein the method is characterized in that the axial compression amount of an arch ring caused by creep is solved The method comprises the following steps: ; and calculating the axial compression quantity caused by creep according to the ratio of the creep to the constant load arch rib bending moment.
7. The method for amplitude modulation of a long-span arch bridge constant load and long-term effect bending moment based on axial compression compensation according to claim 1, wherein the threshold value in S6 is 0.1.

Description

Large-span arch bridge constant load and long-term effect bending moment amplitude modulation method based on axial compression compensation Technical Field The invention relates to the technical field of bridge engineering, in particular to a method for amplitude modulation of a constant load and long-term effect bending moment of a large-span arch bridge based on axial compression compensation. Background For an arch bridge in a large-span bridge, the large-span arch bridge adopting a reasonable arch axis can theoretically realize a zero bending moment state of a rigid arch structure under the action of constant load. However, the actual arch ring deforms under constant load, overall temperature change, shrinkage creep and moving load, thereby causing forces in the main arch. Wherein, the constant load, the integral temperature change and the shrinkage creep are all internal structural forces generated in the form of axial compression deformation, and the bending moment amplitude modulation can be carried out through the compensation of the axial compression quantity. The internal force of the structure generated by the moving load is changed, and the generated internal force effect is inconsistent with the internal force effect distribution generated by the axial compression deformation, so that the internal force of the structure generated by the moving load cannot be completely eliminated only by the compensation of the axial compression amount, but the peak bending stress at each control section of the arch rib under a specific live load distribution mode can be equal by adjusting the length and the rotation angle of the closure section of the arch crown. Therefore, how to provide a method for constant load and long-term effect bending moment amplitude modulation of a large span arch bridge based on axial compression compensation is a problem to be solved by those skilled in the art. Disclosure of Invention In view of the above, the invention provides a method for amplitude modulation of a constant load and a long-term effect bending moment of a large-span arch bridge based on axial compression compensation, which counteracts the axial compression effect caused by constant load, temperature, shrinkage and creep by presetting a displacement opposite to the axial compression deformation direction in a closure stage based on an axial compression compensation idea. In order to achieve the above object, the present invention provides the following technical solutions: A method for amplitude modulation of a constant load and long-term effect bending moment of a large-span arch bridge based on axial compression compensation comprises the following steps: s1, building a bridge rod system unit model of the large-span arch bridge according to design parameters of the large-span arch bridge; s2, respectively calculating the arch ring vault internal force caused by constant load, shrinkage and creep 、And; S3, respectively solving the axial compression quantity of the arch ring caused by constant load, temperature, shrinkage and creep、、And; S4, calculating initial axial compression compensation quantity of the closure; S5, calculating total internal force under the action of ten years of structural creep after the initial axial compression compensation quantity of the closure is applied; S6, judgingAnd an initial constant load internal forceIf the ratio of (2) is less than or equal to the threshold, and if so, recalculate the amount of axial compression caused by creepUpdating the axial compression compensation amountIterative calculation is carried out until the ratio is smaller than a threshold value; s7, outputting the final closure length compensation quantity Is used for guiding construction closure. Optionally, finite element is used to calculate forces in the arch crown caused by constant load, shrinkage and creep in S2、And。 Optionally, solving the axial compression of the arch ring caused by constant loadThe method comprises the following steps: ; In the formula, Is the cross-sectional area of the arch rib,For the dome area,Is the angle between the tangent line of the arch axis and the horizontal line,In order to design the strain,For the curvature of the dome,Is the span length. Optionally, solving for temperature induced arch ring axial compressionThe method comprises the following steps: ; In the formula, Is the difference between the temperature at the time of closure and the average temperature,As a result of the coefficient of expansion of the material,Is the span length. Optionally, solving for shrinkage-induced arch ring axial compressionThe method comprises the following steps: ; and calculating the axial compression amount caused by shrinkage according to the proportion of shrinkage to the bending moment of the constant load arch rib. Optionally, solving the axial compression of the arch ring caused by creepThe method comprises the following steps: ; and calculating the axial compression quantity