Beam body jacking control method based on rigidity-jacking threshold mapping

Abstract

The invention discloses a beam body jacking control method based on rigidity-jacking threshold value mapping, which comprises the following steps: monitoring the bearing reaction and the jacking amount of each supporting point at the bottom of a beam body in the jacking process of the beam body; a jacking threshold value after each supporting point is jacked to the designed jacking amount and a corresponding beam body jacking threshold value are determined according to the rigidity coefficient and the bearing reaction of each supporting point; whether the actual jacking amount of each supporting point meets the requirement or not is judged according to the beam body jacking threshold value, and the jacking amount of the supporting point which does not meet the requirement is adjusted till the actual jacking amount of each supporting point meets the requirement; and meanwhile, the bearing reaction force of each supporting point in the jacking process and the jacking amount adjusting process is controlled to meet the design requirement. According to the method, the jacking threshold value of the supporting points of the beam body is established by utilizing the structural rigidity of the beam body, the reasonable jacking range is defined, and the jacking adjustment precision and adjustment efficiency of the beam body during pushing construction are improved by combining the bearing reaction control of the supporting points.

Description

Technical Field

[0001] The present invention relates to the technical field of beam jacking construction, and more specifically, to a beam jacking control method based on stiffness-jacking threshold mapping. Background Art

[0002] With the continuous development of the transportation network, new bridges may intersect with deep valleys, rivers, roads and railways, etc., and the narrow construction site makes it difficult to transport large machinery to the site. Such projects need to reduce the impact on existing traffic. The method of jacking construction is often used. First, the beam body is lifted up as a whole, and then the jacking translation cylinder is pushed forward for a stroke. After that, the beam body is lowered as a whole and placed on the temporary pad beam. The jacking translation cylinder is retracted to the bottom to complete a jacking stroke. In the jacking process of large-span steel beams, the overall stiffness of the large-span steel beams is small, and the deformation during the jacking process is large and unbalanced. The traditional jacking method does not consider the error control problem of the jacking amount under the condition of flexible deformation. It is mostly estimated based on the experience of the bridge structure, resulting in no basis for the control of the jacking process of the flexible steel beam. The jacking heights of multiple support points are inconsistent. If the empirical accuracy requirements are followed, frequent adjustments are required, and the construction efficiency is low. At the same time, when the jacking force of each point is unbalanced, it is easy for some jacking points to cause the beam structure to be damaged due to excessive jacking force. Therefore, a reasonable control method is urgently needed to meet the needs of efficient and accurate jacking of the beam body. Summary of the invention

[0003] An object of the present invention is to solve at least the above problems and to provide at least the advantages which will be described hereinafter.

[0004] In order to achieve these purposes and other advantages according to the present invention, a beam jacking control method based on stiffness-jacking threshold mapping is provided, including: monitoring the support reaction force and the jacking amount of each support point at the bottom of the beam during the beam jacking process, and determining the jacking threshold of each support point after the jacking to the designed jacking amount and the corresponding beam jacking threshold through the stiffness coefficient and the support reaction force of each support point; judging whether the actual jacking amount of each support point meets the requirement according to the beam jacking threshold, and adjusting the jacking amount of the support points that do not meet the requirement until the actual jacking amount of each support point meets the requirement; and simultaneously controlling the jacking process and the support reaction force of each support point during the jacking amount adjustment process to meet the design requirements.

[0005] Preferably, the stiffness coefficient of each support point at the bottom of the beam body is obtained by establishing a finite element model of the beam body; the lifting threshold of each support point is the ratio of the support reaction force of each support point to its stiffness coefficient.

[0006] Preferably, support points with equal stiffness coefficients are grouped together, and the average of the lifting thresholds of the support points in the same group is the beam lifting threshold corresponding to the support points in the group.

[0007] Preferably, judging whether the actual lifting amount of each supporting point meets the requirements specifically comprises the following steps: S1, judging whether the lifting threshold of each supporting point is within the set lifting threshold range, if it is within the set lifting threshold range, entering step S2, otherwise adjusting the lifting amount of the corresponding supporting point; S2. Calculate the difference between the lifting amount of each support point and the designed lifting amount. If the difference is not greater than the lifting threshold of the beam body, the actual lifting amount of the corresponding support point meets the requirement; otherwise, adjust the lifting amount of the corresponding support point.

[0008] Preferably, the lifting threshold range is set to δd s ±3σ, where δd s is the beam lifting threshold corresponding to each support point, and σ is the standard deviation of the lifting threshold of each support point in the same group.

[0009] Preferably, during the jacking process of the beam body, the support reaction force of each support point is controlled by the following formula to meet the design requirements: In the above formula, F ij 、F mn are the support reaction forces of any supporting point on the beam body; δF is the difference between the support reaction forces of any two supporting points; α is the jacking coefficient. When the subsequent jacking construction is horizontal pushing, α=1; when the subsequent jacking construction is non-horizontal pushing, 0<α<1.

[0010] Preferably, at least two rows of support points are arranged at intervals at the bottom of the beam body, each row of support points includes a plurality of support points arranged at intervals along the longitudinal direction of the beam body, each support point is provided with a jacking device, and each jacking device synchronously lifts the beam body upward to a designed jacking amount.

[0011] The present invention has at least the following beneficial effects: The beam lifting control method based on stiffness-lifting threshold mapping provided by the present invention adopts a position-load dual control strategy. Position control establishes the lifting threshold of each support point through structural stiffness, clarifies the reasonable lifting range, and load control satisfies the design requirements by controlling the support reaction force of each support point, which can effectively avoid excessive local stress on the beam caused by unbalanced load at the support point and reduce the risk of beam damage. Compared with the traditional empirical method adjustment, the adjustment process is clearer, the adjustment efficiency is higher under the condition of ensuring the adjustment accuracy, and the traditional method of repeated trial and error adjustment is avoided, solving the problem of difficult lifting control of large-span flexible steel beams.

[0012] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a flow chart of the beam lifting control method based on stiffness-lifting threshold mapping according to the present invention; Figure 2 It is a structural schematic diagram of the flexible deformation of the beam body after jacking up of the present invention; DETAILED DESCRIPTION

[0014] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0015] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0016] like Figure 1 and Figure 2 As shown, the present invention provides a beam lifting control method based on stiffness-lifting threshold mapping, including: monitoring the support reaction force and the lifting amount of each support point at the bottom of the beam during the beam lifting process, determining the lifting threshold of each support point after the support point is lifted to the designed lifting amount and the corresponding beam lifting threshold through the stiffness coefficient and the support reaction force of each support point; judging whether the actual lifting amount of each support point meets the requirement according to the beam lifting threshold, adjusting the lifting amount of the support points that do not meet the requirement until the actual lifting amount of each support point meets the requirement; and simultaneously controlling the lifting process and the support reaction force of each support point during the lifting amount adjustment process to meet the design requirements.

[0017] In this technical solution, the flexible deformation of the beam body during the lifting process causes an error value between the actual lifting amount and the designed lifting amount during the lifting process. In order to accurately control the lifting amount error of the beam body, the present invention adopts a position-load dual control strategy. For position control, the lifting threshold of each support point is established by the structural stiffness, and this lifting threshold is the maximum error value of the current lifting amount. The lifting threshold of the beam body is further obtained by the lifting threshold of each support point, which is used as a benchmark for evaluating whether the actual lifting amount of the support point meets the requirements. When the lifting amount of each support point meets the requirements, it means that the current lifting deformation of the beam body is within the elastic deformation range of the structure, otherwise it is necessary to adjust the lifting amount of the corresponding support point. After each adjustment of the lifting amount, the lifting threshold of each support point and the lifting threshold of the beam body need to be recalculated according to the adjusted support reaction force until the actual lifting amount of all support points meets the requirements, so as to achieve accurate control of the lifting process of the beam body and clarify the reasonable lifting amount range; as for load control, during the lifting process and the lifting amount adjustment process, the initial lifting rate of each support point is the same, and the reaction force value gradually increases with the lifting process; and under the position control strategy, adjusting the lifting amount of the support point will also affect its support reaction force. In the above process, the support reaction force of each support point is monitored. If the support reaction force of a certain support point does not meet the requirements, it is adjusted by adjusting its lifting rate to avoid excessive local force on the beam body caused by unbalanced load at the support point and causing damage.

[0018] In another technical solution, the stiffness coefficient of each support point at the bottom of the beam is obtained by establishing a finite element model of the beam; the lifting threshold of each support point is the ratio of the support reaction force of each support point to its stiffness coefficient. The support reaction force and actual lifting amount of each support point are monitored by a pressure sensor and a rangefinder, respectively. After the finite element model of the beam is established, continuous support points are taken at possible support positions of the beam jacking path for finite element analysis to obtain the stiffness coefficient of each support point. The lifting threshold δd of each support point ij Calculate as follows: (1) In formula (1), k ij is the stiffness coefficient of each support point, i=1,2…M; j=1,2…N; F ij is the reaction force of each support point, i=1,2…M; j=1,2…N. Figure 2 The four supporting points of the middle beam are shown in the figure. The support reaction forces of each supporting point are F 11 、F 12 、F 21 、F 22 , the lifting thresholds are δd 11 ,δd 12 ,δd 21 ,δd 22 .

[0019] In another technical solution, the support points with the same structural properties of the beam at the corresponding positions are grouped together, and the average of the lifting thresholds of the support points in the same group is the lifting threshold of the beam corresponding to the support points in the group. In the case where the structural properties of the continuous points of the beam are the same and the stiffness of the support points is the same, the lifting thresholds of the beam at the support points are the same, and are the average of the lifting thresholds of the support points. When the structural properties of the corresponding positions of the support points on the beam are different, such as the stiffness of the corresponding positions is too large due to the provision of stiffening ribs, it is necessary to group the support points to accurately set the lifting threshold of the beam.

[0020] Furthermore, judging whether the actual lifting amount of each supporting point meets the requirements specifically includes the following steps: S1, judging whether the lifting threshold of each supporting point is within the set lifting threshold range, if it is within the set lifting threshold range, entering step S2, otherwise adjusting the lifting amount of the corresponding supporting point; In step S1, the lifting threshold range is set to δd s ±3σ, where δd s is the beam lifting threshold corresponding to each support point, σ is the lifting threshold of each support point in the same group δd ij For each support point, when its lifting threshold δd ij When it is within the set lifting threshold range, the lifting threshold is considered to be valid, that is, δd ij satisfy ; Otherwise, the lifting amount of the support point needs to be readjusted.

[0021] S2. Calculate the difference between the lifting amount of each support point and the designed lifting amount. If the difference is not greater than the lifting threshold of the beam body, the actual lifting amount of the corresponding support point meets the requirement; that is, , the actual lifting amount of the corresponding support point meets the requirements; otherwise, the lifting amount of the corresponding support point is adjusted. In another technical solution, during the lifting process of the beam body, the support reaction force of each support point is controlled by the following formula to meet the design requirements: (2) In formula (2), F ij 、F mn are the support reaction forces of any support point on the beam; δF is the difference between the support reaction forces of any two support points; α is the jacking coefficient. When the subsequent jacking construction is flat pushing, α=1; when the subsequent jacking construction is non-flat pushing, 0<α<1. The support reaction forces of each support point need to be kept equal during the flat pushing process. If they are not equal, the local force at some points will be too large, which may easily lead to local damage of the beam. For the non-flat pushing process with a slope of the beam, the support reaction forces of each support point are controlled by the jacking coefficient α to meet the requirements.

[0022] In another technical solution, at least two rows of support points are arranged at intervals at the bottom of the beam body, each row of support points includes a plurality of support points arranged at intervals along the longitudinal direction of the beam body, and each support point is provided with a jacking device, and each jacking device jacks the beam body upward to the designed jacking amount synchronously and at the same rate. During actual construction, the jacking device can use a hydraulic cylinder, and the flow rate of each hydraulic cylinder is controlled by a hydraulic synchronous control system to make the jacking speed of each support point consistent.

[0023] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A beam lifting control method based on stiffness-lifting threshold mapping, characterized in that: include: During the beam lifting process, the support reaction force and lifting amount of each support point at the bottom of the beam are monitored, and the lifting threshold after each support point is lifted to the designed lifting amount and the corresponding beam lifting threshold are determined through the stiffness coefficient and support reaction force of each support point; According to the beam body lifting threshold, it is judged whether the actual lifting amount of each support point meets the requirements, and the lifting amount of the support points that do not meet the requirements is adjusted until the actual lifting amount of each support point meets the requirements; and at the same time, the lifting process and the support reaction force of each support point during the lifting amount adjustment process are controlled to meet the design requirements.

2. The beam lifting control method based on stiffness-lifting threshold mapping according to claim 1, characterized in that: The stiffness coefficient of each support point at the bottom of the beam is obtained by establishing a finite element model of the beam; the lifting threshold of each support point is the ratio of the support reaction force of each support point to its stiffness coefficient.

3. The beam lifting control method based on stiffness-lifting threshold mapping according to claim 1, characterized in that: The support points with equal stiffness coefficients are grouped together, and the average of the lifting thresholds of the support points in the same group is the beam lifting threshold corresponding to the support points in the group.

4. The beam lifting control method based on stiffness-lifting threshold mapping according to claim 3 is characterized in that: Determining whether the actual lifting amount of each support point meets the requirements specifically includes the following steps: S1, judging whether the lifting threshold of each supporting point is within the set lifting threshold range, if it is within the set lifting threshold range, entering step S2, otherwise adjusting the lifting amount of the corresponding supporting point; S2. Calculate the difference between the lifting amount of each support point and the designed lifting amount. If the difference is not greater than the lifting threshold of the beam body, the actual lifting amount of the corresponding support point meets the requirement; otherwise, adjust the lifting amount of the corresponding support point.

5. The beam lifting control method based on stiffness-lifting threshold mapping according to claim 4 is characterized in that: The lifting threshold range is set to δd s ±3σ, where δd s is the beam lifting threshold corresponding to each support point, and σ is the standard deviation of the lifting threshold of each support point in the same group.

6. The beam lifting control method based on stiffness-lifting threshold mapping according to claim 1, characterized in that: During the beam lifting process, the reaction force of each support point is controlled by the following formula to meet the design requirements: In the above formula, F ij 、F mn are the support reaction forces of any supporting point on the beam body; δF is the difference between the support reaction forces of any two supporting points; α is the jacking coefficient. When the subsequent jacking construction is horizontal pushing, α=1; when the subsequent jacking construction is non-horizontal pushing, 0<α<1.

7. The beam lifting control method based on stiffness-lifting threshold mapping according to claim 1, characterized in that: At least two rows of support points are arranged at intervals at the bottom of the beam body, each row of support points includes a plurality of support points arranged at intervals along the longitudinal direction of the beam body, each support point is provided with a jacking device, and each jacking device synchronously jacks the beam body upward to a designed jacking amount.

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