CN-122016103-A - Effective prestress calibration method and monitoring device for high-speed rail continuous beam bridge

Abstract

The invention discloses an effective prestress calibration method and a monitoring device for a high-speed railway continuous beam bridge, and belongs to the technical field of health monitoring of civil engineering structures. The method aims to solve the problem that the effective prestress in the service period of the prestress structure cannot be monitored for a long time in real time in the prior art. According to the method, a high-precision conversion relation from working anchor strain to effective prestress is established through double calibration of combination of finite element analysis and on-site tensioning, and real-time calculation is carried out in the service period by utilizing the relation. The monitoring device comprises a sensing unit and a data processing unit. The invention realizes full-period, real-time and accurate monitoring of the effective prestress state.

Inventors

• BAI MINGLU
• DU BIN
• YANG WENJIE
• HUANG MINGQI
• WANG CHAOFENG
• XU JUNQING
• HOU ZHENGYU
• LIN WEIYOU
• YANG XIAOHUA
• YAO RIGAO
• DAI PEIYI
• DAI SHUAI
• WANG QIAN
• WU TAO
• LIU XIAOQIANG

Assignees

• 中铁二十二局集团有限公司
• 中铁二十二局集团第五工程有限公司
• 厦深铁路广东有限公司

Dates

Publication Date

20260512

Application Date

20260107

Claims (10)

1. 1. An effective prestress calibration method for a high-speed rail continuous beam bridge is characterized by comprising the following steps of: calibration: s1, based on a finite element model of a working anchor, acquiring corresponding relation data of simulated strain and simulated force of a plurality of preset sections under simulated tensioning working conditions and simulated service working conditions; S2, establishing a first calibration relation from simulation strain to simulation force of each section according to the simulation data, and calculating an average conversion coefficient lambda based on the first calibration relation of the two working conditions; S3, measuring the actual strain and the total tensile force of each preset section in the actual prestress tensile process, and establishing a second calibration relation from the actual strain to the total tensile force of each section; s4, determining a third calibration relation for monitoring the service period by combining the conversion coefficient lambda and the second calibration relation; Monitoring: s5, measuring the real-time strain of each preset section in the service period of the structure, and calculating the current effective prestress value based on the third calibration relation and the processed real-time strain.
2. 2. The method according to claim 1, wherein in step S2, the conversion coefficient lambda is calculated by obtaining, for each section, a first coefficient under tension from the first calibration relation Second coefficient under service conditions Calculating the sub-conversion coefficient of the section Averaging the sub-conversion coefficients of all sections to obtain the average conversion coefficient 。
3. 3. The method of claim 2, wherein the number of predetermined cross-sections is three at axially intermediate portions of the working anchor, near the tensioning end and near the anchoring end, respectively.
4. 4. A method according to claim 2 or 3, wherein the first and second calibration relationships are established by linear fitting.
5. 5. The method according to claim 1, wherein in step S5, the processed real-time strain is a strain value obtained by performing temperature drift correction on the measured real-time strain.
6. 6. The method of claim 5, wherein the temperature drift correction is achieved by: S51, setting a reference anchor which is made of the same material as the actually measured working anchor and is in the same environment but not stressed; S52, obtaining the reference strain of the reference anchor at the same position as the actually measured working anchor; and S53, subtracting the corresponding reference strain from the real-time strain to obtain a strain value after temperature drift correction.
7. 7. The method of claim 1, wherein the strain of each of the predetermined sections is measured by at least four strain sensors circumferentially uniformly arranged on the section, and an average of the readings of the at least four strain sensors is used as the strain value of the section.
8. 8. An effective pre-stress monitoring device for a high-speed rail continuous beam bridge for implementing the method of any one of claims 1-7, comprising: the sensing units are configured on a plurality of preset sections of the working anchors and are used for collecting strain signals; A data processing unit communicatively connected to the sensing unit and configured to: storing average conversion coefficients obtained based on finite element analysis ; In the calibration stage, a second calibration relation is established according to data acquired by the sensing unit in the tensioning process, and a third calibration relation is obtained by combining calculation; And in the monitoring stage, calculating and outputting an effective prestress value according to the real-time strain data acquired by the sensing unit and the third calibration relation.
9. 9. The monitoring device of claim 8, wherein the sensing unit further comprises a temperature compensation sensor disposed on a reference anchor, and wherein the data processing unit is further configured to perform temperature drift correction on real-time strain data collected from the working anchor using data from the temperature compensation sensor.
10. 10. The monitoring device according to claim 8 or 9, wherein the sensor in the sensing unit and the outside of the circuit are layered with a protective structure, and the protective structure comprises a sealing layer, a buffer layer and an external protective shell which are sequentially arranged from inside to outside.

Description

Effective prestress calibration method and monitoring device for high-speed rail continuous beam bridge Technical Field The invention relates to the technical field of health monitoring of civil engineering structures, in particular to a long-term and real-time monitoring method and device for effective prestress in a prestressed concrete structure, and particularly relates to an effective prestress calibration method and device for a high-speed rail continuous beam bridge. Background The prestress technology is a key means for improving the performance of a concrete structure, and is characterized in that the tensile stress under the use load is counteracted by the pressure pre-applied by the prestress rib. The effective prestress value actually remained in the prestress rib is the most direct parameter for evaluating the structural performance and the safety state. Insufficient effective prestressing may lead to structural cracking and excessive deformation, while excessive prestressing may cause failure of the tendon or anchor. At present, the control of effective prestress in engineering practice mainly depends on the double control of internal force value and elongation in the construction tensioning stage. However, the method has the obvious limitations that firstly, the tension force of the tensioning end is obviously different from the effective prestress value actually established in the structure after various losses (such as anchor retraction, friction, concrete shrinkage creep and the like), secondly, the traditional method can only provide construction instantaneous data and cannot monitor the effective prestress change caused by material degradation, fatigue load and environmental corrosion in the service period of the structure for decades, and finally, the accuracy of the loss estimation method based on a theoretical formula is insufficient, so that the requirements of modern engineering on refinement and intelligent management and maintenance are difficult to meet. Therefore, there is a need for a technique and apparatus for pre-stress monitoring that can acquire signals directly from a pre-stress anchoring zone and that is efficient in real time and with high accuracy throughout the period from construction to service. Disclosure of Invention In order to overcome the defects of the prior art, the invention provides an effective prestress calibration method and a monitoring device for a high-speed rail continuous beam bridge, and aims to realize accurate, continuous and real-time tracking of an effective prestress state. The principle of the invention is that firstly, under two essentially different stress modes of tensioning (free end stress) and service (anchor hole inner wall stress) of a working anchor, a definite linear proportional relation exists between the strain response and the stressed resultant force, the proportional relation is represented by a sub-conversion coefficient lambda i of each section, secondly, the theoretical relation is subjected to absolute value engineering calibration through the field tensioning process to obtain the calibration coefficient of an actual structure, and finally, the theoretical proportional relation is combined with the field absolute calibration, so that a reliable method for calculating the effective prestress in the service period based on monitoring the strain value of the working anchor is established. In a first aspect, the invention provides an effective prestress calibration method for a high-speed railway continuous beam bridge, comprising the following steps: calibration: s1, based on a finite element model of a working anchor, acquiring corresponding relation data of simulated strain and simulated force of a plurality of preset sections under simulated tensioning working conditions and simulated service working conditions; S2, establishing a first calibration relation from simulation strain to simulation force of each section according to the simulation data, and calculating an average conversion coefficient lambda based on the first calibration relation of the two working conditions; S3, measuring the actual strain and the total tensile force of each preset section in the actual prestress tensile process, and establishing a second calibration relation from the actual strain to the total tensile force of each section; s4, determining a third calibration relation for monitoring the service period by combining the conversion coefficient lambda and the second calibration relation; Monitoring: s5, measuring the real-time strain of each preset section in the service period of the structure, and calculating the current effective prestress value based on the third calibration relation and the processed real-time strain. Further, in step S2, the conversion coefficient lambda is calculated by obtaining, for each section, a first coefficient under the tensioning condition from the first calibration relationSecond coefficient under service con