Construction monitoring method and system for arch bridge tie bar replacement under unknown cable force state

Abstract

The invention discloses a construction monitoring method and system for replacement of an arch bridge tie bar in an unknown cable force state. The construction monitoring method comprises the following steps: acquiring horizontal displacement of an arch foot, vertical displacement of an arch rib, vertical displacement of a bridge floor and stress of a tie bar inhaul cable through a sensor mounted on an arch bridge; the maximum fluctuation range of arch foot horizontal displacement, arch rib vertical displacement, bridge floor vertical displacement and tie bar inhaul cable stress is obtained through finite element simulation calculation, threshold values of the arch foot horizontal displacement, the arch rib vertical displacement, the bridge floor vertical displacement and the tie bar inhaul cable stress are determined according to the maximum fluctuation range, and monitoring parameter threshold values are generated. Compared with a previous process which depends on artificial experience for judgment, the method adopts a multi-dimensional monitoring mode, mainly focuses on monitoring arch foot horizontal displacement, arch rib vertical displacement, bridge floor vertical displacement and tie bar inhaul cable stress parameters, prejudges key parameter thresholds, synchronously adjusts tension resultant force when the thresholds are exceeded, and achieves the purpose of accurate adjustment of the tension resultant force when the tension resultant force exceeds the thresholds. The cable force error is effectively controlled, and the influence of the cable force deviation on the arch foot displacement and the bridge floor line shape is further restrained.

Description

Technical Field

[0001] The present invention relates to the field of information technology, and particularly to a construction monitoring method and system for replacing the arch bridge tie rod in an unknown cable force state. Background Art

[0002] The arch bridge tie rod replacement project aims to solve the potential safety hazards of the bridge structure caused by material aging, corrosion or damage, and restore the bearing capacity and extend the service life by replacing the failed components. In recent years, as the early-built tied arch bridges in China gradually enter the peak maintenance period, the tie rod replacement projects have shown a large-scale growth. The tie rod, as the core load-bearing component to balance the horizontal thrust of the arch feet, its service performance directly affects the overall stability of the bridge. However, in actual replacement operations, the cable force of the old tie rod is often difficult to accurately measure due to factors such as long-term load changes, material relaxation and environmental erosion. If directly replaced, it may lead to risks such as excessive displacement of the arch feet and sudden change of the bridge deck alignment due to force imbalance. Moreover, the anchor head of the old tie rod was not reserved for the construction space of relaxation during design, resulting in the replacement process can only be carried out by cutting method, which greatly increases the difficulty of construction process control. The existing traditional replacement technical methods mostly rely on experience control and lack the dynamic monitoring and real-time adjustment mechanism for key parameters.

[0003] Obtain the horizontal displacement of the arch feet, the vertical displacement of the arch rib, the vertical displacement of the bridge deck, and the stress parameters of the tie rod cable through sensors

[0004] Obtain the maximum fluctuation range of the horizontal displacement of the arch feet, the vertical displacement of the arch rib, the vertical displacement of the bridge deck, and the stress of the tie rod cable through simulation calculation, and determine the threshold according to the maximum fluctuation range

[0005] During the construction of tie rod replacement, adjust the tension cable force of the new tie rod according to the monitoring parameter threshold Summary of the Invention

[0006] The purpose of the present invention is to solve the problems of the above-mentioned existing construction technologies, and provide a construction monitoring method for replacing the arch bridge tie rod in an unknown cable force state to ensure the stability of the bridge alignment and force during the replacement process. The construction monitoring method mainly includes:

[0007] Obtain the horizontal displacement of the arch feet, the vertical displacement of the arch rib, the vertical displacement of the bridge deck, and the stress of the tie rod cable through the sensors installed on the arch bridge, and obtain the number of old steel strands to be cut for each batch of tie rod replacement according to the total value of the new tension cable force;

[0008] Obtain the maximum fluctuation range of the horizontal displacement of the arch feet, the vertical displacement of the arch rib, the vertical displacement of the bridge deck, and the stress of the tie rod cable through finite element simulation calculation, determine the thresholds of the horizontal displacement of the arch feet, the vertical displacement of the arch rib, the vertical displacement of the bridge deck, and the stress of the tie rod cable according to the maximum fluctuation range, and generate the monitoring parameter thresholds;

[0009] Divide the construction batches of tie rod replacement, and carry out batch-cross operations of cutting the old tie rods and tensioning the new tie rods. According to the monitoring parameter thresholds, adjust the tension resultant force of the new tie rods. During the tie rod replacement process, if the parameters exceed the monitoring parameter thresholds, increase or decrease the tension force of the corresponding new tie rod according to the mechanical relationship, with the criterion that the bridge alignment does not change significantly within the batches of cutting the old tie rods and tensioning the new tie rods.

[0010] Preferably, the monitoring period for the horizontal displacement of the arch feet and the stress of the tie rod cables is for each construction process, the monitoring period for the vertical displacement of the arch ribs is for each construction batch, the monitoring period for the vertical displacement of the bridge deck is 1 / 4 of the total construction batches, and the monitoring resolutions for the horizontal displacement of the arch feet, the vertical displacement of the arch ribs, and the vertical displacement of the bridge deck are ≤ 0.1 mm, and the monitoring resolution for the stress of the tie rod cables is ≤ 1 με.

[0011] Preferably, the number of construction batches for tie rod replacement ≥ 15, the threshold for the horizontal displacement of the arch feet ≤ 1 mm, and the thresholds for the vertical displacements of the arch ribs and the bridge deck ≤ 10 mm.

[0012] Preferably, a static time of half an hour is set between two construction batches of tie rod replacement, a static time of two hours is set when the total number of construction batches of tie rod replacement reaches 1 / 4, 1 / 2, and 3 / 4, and a static time of twenty-four hours is set after the completion of the total construction batches of tie rod replacement.

[0013] Preferably, when the horizontal displacement of the arch feet exceeds its threshold, adjust the tension force of the tie rod cables in this construction batch. When two of the vertical displacements of the arch ribs, the bridge deck, and the stress of the tie rod cables exceed the thresholds, adjust the tension force of the tie rod cables in this construction batch. When the horizontal displacement of the arch feet is outward, the vertical displacement of the bridge deck is downward, and the vertical displacement of the arch ribs is downward, increase the tension force of the new tie rod according to the magnitude of the exceeded displacement, otherwise decrease the tension force of the new tie rod. The target of adjusting the tension force is that the bridge alignment does not change significantly within the batches of cutting the old tie rods and tensioning the new tie rods.

[0014] A construction monitoring system for the construction monitoring method of arch bridge tie rod replacement under the unknown state of cable force as described above, including: a horizontal displacement monitoring subsystem of the arch feet, a vertical displacement monitoring subsystem of the arch ribs, a vertical displacement monitoring subsystem of the bridge deck, and a stress monitoring subsystem of the tie rod cables. The horizontal displacement monitoring subsystem of the arch feet includes at least two monitoring points symmetrically arranged at each arch foot. The vertical displacement monitoring subsystem of the arch ribs includes at least two monitoring points arranged at each cross-section of each arch rib and monitoring points arranged at the mid-span and quarter points in the longitudinal bridge direction. The vertical displacement monitoring subsystem of the bridge deck includes at least two monitoring points arranged at each cross-section of the bridge deck and monitoring points arranged at the mid-span and quarter points in the longitudinal bridge direction. The stress monitoring subsystem of the tie rod cables includes a dynamic real-time monitoring module for the jacking force of the new tie rod tensioning jack and a sampling wire stress monitoring module for the old tie rods.

[0015] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects:

[0016] The present invention provides a construction monitoring method for replacing the arch bridge tie rod under the unknown cable force state. By optimizing the cable force dynamic regulation mechanism, this method significantly reduces the risk of error accumulation caused by unknown cable force in traditional empirical construction. Compared with the previous process that relied on manual experience judgment, it adopts a multi-dimensional monitoring method, mainly focusing on monitoring the horizontal displacement of the arch foot, the vertical displacement of the arch rib, the vertical displacement of the bridge deck, and the stress parameters of the tie rod cables. Combining with finite element simulation to predict the key parameter thresholds, for the cases exceeding the thresholds, the tensioning resultant force is adjusted synchronously to effectively control the cable force error, further suppressing the influence of the cable force deviation on the arch foot displacement and the bridge deck alignment, and finally achieving a significant reduction in the error range. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a flowchart of the present invention;

[0018] Figure 2 is a layout diagram of the horizontal displacement measurement points of the arch seat;

[0019] Figure 3 is a layout diagram of the vertical displacement measurement points of the arch rib;

[0020] Figure 4 is a layout diagram of the vertical displacement measurement points of the bridge deck;

[0021] Figure 5 is a layout diagram of the old tie rod;

[0022] Figure 6 is a layout diagram of the new tie rod;

[0023] Figure 7 is a table of tie rod replacement batches; DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described in detail below with reference to the drawings and specific embodiments.

[0025] As Figure 1-7 , a construction monitoring method for replacing the arch bridge tie rod under the unknown cable force state in this embodiment may specifically include:

[0026] Obtain the horizontal displacement of the arch foot, the vertical displacement of the arch rib, the vertical displacement of the bridge deck, and the stress of the tie rod cable through the sensors installed on the arch bridge, and obtain the number of old steel strands to be cut for each batch of tie rod replacement according to the total value of the new tensioned cable force;

[0027] Obtain the maximum fluctuation ranges of the horizontal displacement of the arch foot, the vertical displacement of the arch rib, the vertical displacement of the bridge deck, and the stress of the tie rod cable through finite element simulation calculations. Determine the thresholds of the horizontal displacement of the arch foot, the vertical displacement of the arch rib, the vertical displacement of the bridge deck, and the stress of the tie rod cable based on the maximum fluctuation ranges, and generate the monitoring parameter thresholds.

[0028] Divide the construction batches of tie rod replacement, and carry out batch-by-batch cross operations of cutting the old tie rods and tensioning the new tie rods. According to the monitoring parameter thresholds, adjust the tensioning resultant force of the new tie rods. During the tie rod replacement process, if the parameters exceed the monitoring parameter thresholds, increase or decrease the corresponding tensioning cable forces of the new tie rods respectively according to the mechanical relationship, with the criterion that the bridge alignment does not change significantly within the batches of cutting the old tie rods and tensioning the new tie rods.

[0029] The monitoring periods of the horizontal displacement of the arch foot and the stress of the tie rod cable are for each construction process, the monitoring period of the vertical displacement of the arch rib is for each construction batch, the monitoring period of the vertical displacement of the bridge deck is 1 / 4 of the total construction batches, and the monitoring resolutions of the horizontal displacement of the arch foot, the vertical displacement of the arch rib, and the vertical displacement of the bridge deck are ≤0.1 mm, and the monitoring resolution of the stress of the tie rod cable is ≤1 με.

[0030] Set the number of construction batches of tie rod replacement ≥15, the threshold of the horizontal displacement of the arch foot ≤1 mm, and the thresholds of the vertical displacements of the arch rib and the bridge deck ≤10 mm. Take the threshold of the horizontal displacement of the arch foot as the main control parameter, and the remaining vertical displacements of the arch rib, the vertical displacement of the bridge deck, and the stress of the tie rod cable as secondary parameters.

[0031] The following is an example of the step of dividing the construction batches of tie rod replacement: According to the original bridge drawings, the total number of old tie rods is 40, 20 on each of the north and south sides. Number them one by one according to the cutting batches, as shown in the appendix Figure 5 As shown, the tensioning resultant force for each is 1400 KN. Combining with the overhaul design drawings, the total number of new tie rods is 8, 4 on each of the north and south sides. Number them in sequence according to the north-south direction as shown in the appendix Figure 6 As shown, assuming the tension of the old tie rods remains unchanged and the total resultant force is 56000 KN, it can be known that the tension of each new tie rod should be 7000 KN. Divide the tensioning batches into 20 batches, with each batch being 5% of the resultant force of the new tie rods to be tensioned, and cut 2 old tie rods. The specific division is shown in the appendix Figure 6 (Table 1).

[0032] In the step of carrying out batch-by-batch cross operations of cutting the old tie rods and tensioning the new tie rods, in this step, the cutting of the old tie rods and the tensioning of the new tie rods are symmetrically and synchronously constructed along the longitudinal and transverse axes of the bridge. Jacks and other tensioning equipment need to be installed during the tensioning process. The working space is small, and two of them are tensioned unilaterally at a time. The specific division is shown in Figure 6As shown in (Table 1), the incision of each old tie rod along the bridge direction should not be less than two places. The old tie rods of this bridge are in an unbonded state. At both ends of the main span, the upper deck paving layer with a length of 1m × width of 1m is removed to expose the old tie rods in the old tie rod box. When cutting the old tie rods, fixing devices should be adopted at both ends of the old tie rods to prevent the cut old tie rods from swinging and hurting people.

[0033] Set a static time of half an hour between two construction batches of tie rod replacement. Set a static time of two hours when the total construction batches of tie rod replacement reach 1 / 4, 1 / 2, and 3 / 4. Set a static time of 24 hours after the completion of the total construction batches of tie rod replacement. In this embodiment, since the total construction batches of tie rod replacement are 20 batches, so after the construction reaches the 5th batch, the 10th batch, and the 15th batch, it is necessary to stand still for 2 hours for observation. After the completion of all construction batches of tie rod replacement, it is necessary to stand still for one day (24 hours) for observation. Avoid changes in the dead load on the bridge during the static process.

[0034] In the above step, adjust the tensile resultant force of the new tie rod according to the monitoring parameter threshold. During the tie rod replacement process, if the parameter exceeds the monitoring parameter threshold, increase or decrease the tensile force of the corresponding new tie rod according to the mechanical relationship. In this step, when the horizontal displacement of the arch foot is 1.2mm inward, exceeding the arch foot horizontal displacement threshold of 1mm, according to the mechanical relationship, the tensile force of the next batch should be appropriately reduced by 10%. Otherwise, increase the tie rod tensile force by 10%. When one of the vertical displacement of the arch rib, the vertical displacement of the bridge deck, and the stress of the tie rod cable does not meet the threshold requirements, do not perform construction adjustment and closely monitor the over-limit part. When two or more of the vertical displacement of the arch rib, the vertical displacement of the bridge deck, and the stress of the tie rod cable exceed the threshold, adjust the tensile force of the new tie rod in this batch. If the horizontal displacement of the arch foot is outward, the vertical displacement of the bridge deck is downward, and the vertical displacement of the arch rib is downward, increase the tensile force of the new tie rod according to the magnitude of the exceeded displacement. Otherwise, reduce the tensile force of the new tie rod. The goal of adjusting the tensile force is that the bridge alignment does not change significantly during the batch of cutting the old tie rod and tensioning the new tie rod.

[0035] A construction monitoring system for the tie rod replacement of an arch bridge based on the above construction monitoring method under the unknown state of cable force includes: an arch foot horizontal displacement monitoring subsystem, an arch rib vertical displacement monitoring subsystem, a bridge deck vertical displacement monitoring subsystem, and a tie rod cable stress monitoring subsystem. The arch foot horizontal displacement monitoring subsystem includes two monitoring points symmetrically arranged at each arch foot. As shown in the appendix Figure 2 As shown, weld a total station prism on it, set up a total station at a fixed position, and measure multiple times to reduce errors;

[0036] As shown in the appendix Figure 3 As shown, the arch rib vertical displacement monitoring subsystem includes 2 monitoring points set at each cross-section of each arch rib and monitoring points set at the mid-span and quarter points in the longitudinal bridge direction, with a total of 20 monitoring points;

[0037] As shown in the appendixFigure 4 As shown in Figure 4 , the vertical displacement monitoring subsystem of the bridge deck includes 3 monitoring points set at each cross-section of the bridge deck and monitoring points set at the mid-span and quarter points in the longitudinal direction of the bridge, with a total of 21 monitoring points, which are measured by a laser level.

[0038] The stress monitoring subsystem of the tie rod cable includes a dynamic real-time monitoring module for the jacking force of the new tie rod tensioning jack and a stress monitoring module for the sampled steel wires of the old tie rod.

[0039] The above description is only the preferred embodiment of the present application and an explanation of the technical principles applied. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the concept of the present application. For example, the technical solutions formed by mutually replacing the above features with the technical features (but not limited to) having similar functions disclosed in the present application.

Claims

1. A construction monitoring method for replacing the tie rod of an arch bridge in a state where the cable force is unknown, characterized in that The method includes: Obtaining the horizontal displacement of the arch springing, the vertical displacement of the arch rib, the vertical displacement of the bridge deck, and the stress of the tie rod cable through sensors installed on the arch bridge; Obtaining the maximum fluctuation range of the horizontal displacement of the arch springing, the vertical displacement of the arch rib, the vertical displacement of the bridge deck, and the stress of the tie rod cable through finite element simulation calculation, determining the thresholds of the horizontal displacement of the arch springing, the vertical displacement of the arch rib, the vertical displacement of the bridge deck, and the stress of the tie rod cable according to the maximum fluctuation range, and generating the monitoring parameter thresholds; Dividing the construction batches of tie rod replacement, carrying out batch-by-batch cross operations of cutting the old tie rod and tensioning the new tie rod, and adjusting the tensioning force of the new tie rod according to the monitoring parameter thresholds.

2. The method according to claim 1, characterized in that : The monitoring period of the horizontal displacement of the arch springing and the stress of the tie rod cable is each construction process, the monitoring period of the vertical displacement of the arch rib is each construction batch, the monitoring period of the vertical displacement of the bridge deck is 1 / 4 of the total construction batches, and the monitoring resolution of the horizontal displacement of the arch springing, the vertical displacement of the arch rib, and the vertical displacement of the bridge deck ≤ 0.1 mm, and the monitoring resolution of the stress of the tie rod cable ≤ 1 με.

3. The method according to claim 1, wherein, The determination of the thresholds of the horizontal displacement of the arch springing, the vertical displacement of the arch rib, the vertical displacement of the bridge deck, and the stress of the tie rod cable according to the maximum fluctuation range and the generation of the monitoring parameter thresholds are characterized in that: the number of construction batches of tie rod replacement ≥ 15, the threshold of the horizontal displacement of the arch springing ≤ 1 mm, and the thresholds of the vertical displacement of the arch rib and the vertical displacement of the bridge deck ≤ 10 mm.

4. The method according to claim 1, wherein : A static time of half an hour is set between two construction batches of tie rod replacement, a static time of two hours is set when the total number of construction batches of tie rod replacement reaches 1 / 4, 1 / 2, and 3 / 4, and a static time of 24 hours is set after the completion of the total number of construction batches of tie rod replacement.

5. The method according to claim 1, wherein Adjusting the tensioning force of the new tie rod according to the monitoring parameter thresholds is characterized in that: when the horizontal displacement of the arch springing exceeds its threshold, the tensioning force of the tie rod in this construction batch is adjusted, and when two of the vertical displacement of the arch rib, the vertical displacement of the bridge deck, and the stress of the tie rod cable exceed the threshold, the tensioning force of the tie rod in this construction batch is adjusted.

6. A construction monitoring system for replacing the tie rod of an arch bridge under the unknown cable force state based on the construction monitoring method as described in any one of claims 1-5, characterized in that, The system includes: a horizontal displacement monitoring subsystem of the arch springing, a vertical displacement monitoring subsystem of the arch rib, a vertical displacement monitoring subsystem of the bridge deck, and a stress monitoring subsystem of the tie rod cable. The horizontal displacement monitoring subsystem of the arch springing includes at least two monitoring points symmetrically arranged at each arch springing. The vertical displacement monitoring subsystem of the arch rib includes at least two monitoring points arranged at each cross-section of each arch rib and monitoring points arranged at the mid-span and quarter points in the longitudinal bridge direction. The vertical displacement monitoring subsystem of the bridge deck includes at least two monitoring points arranged at each cross-section of the bridge deck and monitoring points arranged at the mid-span and quarter points in the longitudinal bridge direction. The stress monitoring subsystem of the tie rod cable includes a dynamic real-time monitoring module for the jacking force of the new tie rod tensioning jack and a stress monitoring module for the sampling steel wires of the old tie rod.

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