CN-116067592-B - Rapid diagnosis method for longitudinal bridge damage of prefabricated assembled girder bridge

CN116067592BCN 116067592 BCN116067592 BCN 116067592BCN-116067592-B

Abstract

The invention relates to the technical field of bridge health monitoring and detection, and particularly discloses a method for rapidly diagnosing longitudinal bridge damage of a prefabricated assembled girder bridge, which comprises the steps of collecting actual structural parameters of the bridge, and establishing a bridge finite element calculation model for calculating a theoretical strain influence line; the method comprises the steps of arranging strain measuring points at the longitudinal midspan positions of two outer side beams and a middle beam of a prefabricated assembled beam, carrying out a quasi-static loading test, extracting strain of the strain measuring points of a beam bridge, fitting and drawing strain influence lines, solving total strain meters of the strain measuring points of the two outer side beams, calculating total strain meter change amplitude deltas of the strain measuring points of the two outer side beams, establishing a delta S histogram of the two outer side beams and the middle beam in the same coordinate axis, and obtaining qualitative diagnosis results by comparing with a qualitative diagnosis system of longitudinal bridge damage. The rapid diagnosis method for the longitudinal bridge damage of the prefabricated assembled girder bridge is loaded by adopting a quasi-static loading method, has short diagnosis time, does not interrupt traffic, improves economy, realizes rapid comprehensive diagnosis of the longitudinal bridge damage of the prefabricated assembled girder bridge, and improves diagnosis accuracy.

Inventors

HAO TIANZHI
YU MENGSHENG
DENG NIANCHUN
NING JIEJUN
CHEN QIFENG
CHEN XIAOMING

Assignees

广西北投交通养护科技集团有限公司
广西交科集团有限公司

Dates

Publication Date: 20260508
Application Date: 20221214

Claims (7)

1. The rapid diagnosis method for the longitudinal bridge damage of the prefabricated assembled girder bridge is characterized by comprising the following steps of: (1) Establishing a bridge finite element calculation model for calculating a theoretical strain influence line according to the bridge theoretical structural parameters; (2) Strain measuring points A, E, C are respectively arranged in the longitudinal midspan of the two outer side beams and the middle beam of the prefabricated assembled girder bridge, and then a quasi static loading test is carried out, wherein a test loading vehicle uniformly runs along the bridge deck at a low speed from the bridge end to the bridge tail to apply a moving load to the girder bridge; (3) Extracting the strain of the beam bridge strain measuring point under the action of a moving load, and fitting and drawing a strain influence line; (4) The total strain meter of the two outer beam strain measuring points A, E is obtained, and the total strain meter is the total wrapping area between the strain influence line at the bridge structure measuring point and the abscissa axis under the action of moving load; (5) Calculating the total strain meter change amplitude of the measuring point A, E 、 The total strain meter change amplitude is obtained by subtracting a theoretical total strain meter from the total strain meter obtained in the step (4), wherein the theoretical total strain meter is the total envelope area between a theoretical strain influence line and an abscissa axis; (6) Establishing both in the same coordinate axis The histogram is used for comparing with a qualitative diagnosis system of the longitudinal bridge damage to obtain a qualitative diagnosis result; the diagnostic criteria of the qualitative diagnostic chart of the longitudinal bridge injury are as follows: And When the state is zero, the prefabricated Liang Qiaoliang body is in a nondestructive state; Is negative, When the time period is zero, the outer edge Liang Shousun of the measuring point A is positioned; Is positive in shape, When the value is zero, the side Liang Shousun adjacent to the outer beam where the measuring point A is located; And The middle beam is damaged when the two are positive; Is zero, If yes, a side Liang Shousun adjacent to the outer beam where the measuring point E is located; Is zero, If negative, the outside Liang Shousun of the measuring point E is located; (7) Dividing a damaged Liang Tice point strain influence line into n sections at equal intervals along the longitudinal direction by taking c as the length, and obtaining section strain meters of each section ; (8) Calculating the change amplitude of the interval strain meter The change amplitude of the interval strain meter is obtained by subtracting the theoretical interval total strain meter from the interval strain meter obtained in the actual measurement in the step (7); (9) According to the change amplitude of the interval strain meter Positioning and quantifying the damage to the longitudinal bridge direction, The section with the largest absolute value is the position section of the damage, and when the damaged beam body is a loading beam, the damage degree of the damaged beam body is that The damage degree of the damaged beam body is as follows when the damaged beam body is a non-loaded beam Four times the absolute value.
2. The method for rapid diagnosis of longitudinal bridge damage of a prefabricated assembled girder bridge according to claim 1, wherein in the step (1), the finite element calculation model calculation is based on the following formula: in the formula, Is that The strain influence line of the number longitudinal beam is L, EI is the rigidity of the section of the measuring point, L is the distance from the section of the measuring point to the bridge end, y is the distance from the lower edge of the section of the measuring point to the neutral axis of the section, x is the distance between the acting position of the moving load F and the bridge end, The actual transverse distribution coefficient of the k-shaped longitudinal beam.
3. The rapid diagnosis method for longitudinal bridge damage of a prefabricated assembled girder bridge according to claim 1, wherein in the step (2), the test loading vehicle loads a single-row vehicle under a normal loading path in a loading path and an arrangement mode, and the three-axis loading vehicle or the four-axis loading vehicle loads.
4. The method for rapid diagnosis of longitudinal bridge damage of a prefabricated assembled girder bridge according to claim 1, wherein in the step (2), the test loading vehicle passes through the bridge deck along the center line of the bridge deck, and the uniform low speed is not more than 50% of the speed limit.
5. The rapid diagnosis method for longitudinal bridge damage of a prefabricated assembled girder bridge according to claim 1, wherein in the step (3), a least square fitting is adopted to draw a strain influence line.
6. The rapid diagnosis method for longitudinal bridge damage of prefabricated assembled girder bridge according to claim 1, wherein in the step (7), the interval strain meter The calculation formula is as follows: Wherein l i is the abscissa value of the middle position of the interval i, c is the dividing length of each interval of the strain influence line of the measuring point, And (5) a strain influence line expression in the measuring point interval i.
7. The method for rapid diagnosis of longitudinal bridge damage of a prefabricated assembled girder bridge according to claim 1, wherein in the step (8), the range of the interval strain meter change is The calculation formula is as follows: wherein l i is the horizontal coordinate value of the middle position of the interval i, and c is the dividing length of each interval of the strain influence line of the measuring point; Actually measuring a strain influence line for a beam damage state measuring point interval i; The strain influence line of the measurement point interval i in the nondestructive state of the beam body is the theoretical strain influence line.

Description

Rapid diagnosis method for longitudinal bridge damage of prefabricated assembled girder bridge Technical Field The invention belongs to the technical field of bridge health monitoring and detection, and particularly relates to a rapid diagnosis method for longitudinal bridge damage of a prefabricated assembled girder bridge. Background The prefabricated assembled beam bridge has the advantages of quick construction, reliable quality, durability, environmental protection and the like, and is widely applied to bridge engineering in China. During the service period of the bridge, due to the comprehensive long-term effect of various natural environment factors, part of the bridge is gradually damaged and aged along with the increase of the service time, the bridge strength is reduced, the stress performance is reduced, the reliability is reduced, and the safety of pedestrians and driving can be seriously endangered. Liang Tizong bridge directional damage represented by concrete cracking, breakage and carbonization is an important factor endangering bridge safety, and rapid and accurate diagnosis of the damage is performed, so that the bridge is one of effective measures for ensuring bridge safety operation and avoiding bridge safety accidents. The conventional damage diagnosis method for the service bridge is mainly a diagnosis method based on appearance investigation and a diagnosis method based on a load test. The diagnostic method based on appearance investigation is characterized in that appearance diseases of the bridge are counted and analyzed mainly according to engineering experience and subjective judgment of detection personnel, and then the technical condition grade of the bridge is assessed according to the technical condition assessment standard of the highway bridge by combining analysis results. The diagnosis method based on the load test is a bridge damage diagnosis method widely adopted in bridge detection at present, and is more visual and objective than the diagnosis method of appearance investigation. The load test is divided into a static load test and a dynamic load test, wherein the static load test mainly adopts a graded loading method, external load basically equivalent to design load or use load is applied to the bridge structure, the change of the characteristics of deflection, stress, cracks, transverse distribution coefficients and the like of a control part and a control section of the bridge structure under the action of each level of test load is tested by utilizing a detection instrument, and an actual measurement value is compared with a theoretical calculation value of the structure under the action of corresponding load, so that the whole health condition of the bridge structure is diagnosed. The dynamic load test is mainly to test dynamic deflection, dynamic strain and modal parameters of each control part on a bridge structure by performing impulse test, driving, jumping, braking excitation or other excitation tests on the bridge structure, and then identify damaged parts of the structure through the modal parameters. The diagnosis method based on the load test mainly has the defects that traffic needs to be sealed for a long time in the implementation process of the diagnosis method, interference can be generated on normal traffic, the diagnosis method is large in loading capacity, and a step-by-step loading and unloading mode is adopted, so that the loading process is tedious and long in time consumption and poor in economy, the diagnosis method mainly is used for diagnosing the whole health condition of the bridge, and is single in diagnosis index, thicker in diagnosis result and poor in accuracy. The method is difficult to quickly and accurately diagnose the longitudinal damage of the prefabricated assembled girder bridge. The method for diagnosing the damage of the prefabricated assembled beam bridge, which has the advantages of no traffic interruption, simple and quick operation and fine diagnosis result, has quick and good economy in the test process, has finer diagnosis result on the damage of the bridge, can provide reliable and effective basis for prolonging the service life of the bridge and formulating a maintenance scheme, and has remarkable social benefit. Disclosure of Invention The invention aims to provide a rapid diagnosis method for longitudinal bridge damage of a prefabricated assembled girder bridge, and overcomes the defect that the conventional diagnosis method is difficult to rapidly diagnose, position and quantitatively diagnose the longitudinal bridge damage of the prefabricated assembled girder bridge. In order to achieve the above purpose, the invention provides a rapid diagnosis method for longitudinal bridge damage of a prefabricated assembled girder bridge, which comprises the following steps: (1) Establishing a bridge finite element calculation model for calculating a theoretical strain influence line according to the bridge theoretical struc