Method and device for testing traction force of cable strand during erection of main cable of suspension bridge through PPWS method

Abstract

The invention relates to the technical field of suspension bridge main cable erection, in particular to a cable strand traction force testing method and device during suspension bridge main cable erection through a PPWS method. The test method comprises the following steps: firstly, arranging a lug strain sensor, adopting a full-bridge measurement circuit, symmetrically pasting resistance strain gauges on the inner sides of a left plate and a right plate of a lug along the axial direction of the lug respectively, arranging a compensation block which is made of the same material as the lug and does not bear, and pasting a resistance strain gauge for temperature compensation on the compensation block; secondly, the tilt angle sensors are explained, the upper tilt angle sensors are arranged on the lug base and the upper pull rod in the axis direction respectively, the tilt angle sensor on the lug base is used for measuring the horizontal tilt angle of the tensile force borne by the lug base, and the tilt angle sensor on the pull rod can be used for measuring the horizontal tilt angle of the traction force when the cable strand is dragged by the dragger. Finally, the accurate cable strand traction force in the anchor head entering direction of the cable strand is obtained through the force balance theorem.

Description

[Technical field]

[0001] The invention relates to the technical field of main cable erection of a suspension bridge, and in particular to a cable strand traction force testing method and device when erecting a main cable of a suspension bridge using a PPWS method. [Background technology]

[0002] At present, the prefabricated parallel strand (PPWS) method is widely used in the construction of large-span suspension bridges in China to erect the main cable, and the portal puller type traction system is often used to pull the main cable strand. The erection of the main cable strand is one of the key processes in the construction of suspension bridges, and its cable quality will directly affect the long-term stress and line shape of the bridge. During the construction stage of the superstructure of the suspension bridge, the monitoring of the cable force of the traction system during the erection of the main cable strand has always been the focus and difficulty of the construction process. The traction force of the main cable strand can be used as an important indicator to reflect the operating status of the traction system during the erection of the main cable strand. By real-time monitoring of the traction force when the puller pulls the cable strand, the stress conditions of the traction system at different positions during the pulling process and when passing through the portal, anchor and main tower pulley block can be obtained, which is of great significance for the prevention and maintenance of the main cable erection process of the suspension bridge, and can also provide important data support for the subsequent construction of larger span suspension bridges.

[0003] During the installation of the main cable of the suspension bridge, the on-site cable pulling operation steps are cumbersome. Each time a cable strand is pulled, the construction workers need to manually install and remove the anchor head. The precise cable strand traction force test device should not hinder on-site operations and should not be easily damaged. In addition, factors such as the complex structure of the cable strand traction system, limited sensor layout space, and construction cost control make it difficult to accurately test the cable strand traction force during the installation of the main cable of the suspension bridge. Some technicians have calculated the traction force of the cable strand when the puller is at a specific position during the installation of the main cable through force state analysis, but there is currently no test method and device that can accurately and real-time measure the cable strand traction force. [Summary of the invention]

[0004] The object of the present invention is to provide a method and device for testing the traction force of a puller on a cable strand when the main cable of a suspension bridge is erected, so as to solve the above-mentioned problems.

[0005] Another purpose of the present invention is to analyze the full-course traction data of the pulling cable strands of the puller to provide a reference for the subsequent construction of a larger-span suspension bridge.

[0006] The present invention is achieved in that:

[0007] A cable strand traction force testing device for the installation of the main cable of a suspension bridge includes an ear seat strain sensor and an inclination sensor. First, the ear seat strain sensor is arranged, and a full-bridge measurement circuit is adopted. The resistance strain gauges R1 and R3 are respectively pasted symmetrically along the axis of the ear seat on the inner side of the left and right plates of the ear seat, and a compensation block with the same material as the ear seat and no load is set, on which the resistance strain gauges R2 and R4 for temperature compensation are pasted. R1, R2, R3, and R4 form a full-bridge measurement circuit, and the output signal of this bridge is proportional to the tensile force F on the ear seat. The bridge circuit can realize self-compensation of temperature, and the resistance strain gauges R1 and R3 are symmetrically pasted on the inner side of the left and right plates of the ear seat, which can eliminate the bending moment effect on the ear seat caused by the lateral swing of the puller when pulling the cable strand. Secondly, due to the influence of gravity of the anchor head and the cable strand during the pulling process, the tensile force measured by the ear seat strain sensor is not the traction force of the cable strand pulled by the puller. It is necessary to arrange the inclination sensor 01 and the inclination sensor 02 along the axial direction of the ear seat and the upper pull rod respectively, and use the force balance theorem to obtain the accurate cable strand traction force along the direction of the cable strand entering the anchor head.

[0008] Compared with the prior art, the present invention has the following beneficial effects:

[0009] The invention clarifies the true direction and magnitude of the traction force when the puller pulls the cable strand, and can measure the traction force when the puller pulls the cable strand in real time without interfering with on-site operations. The invention is simple to operate, has high test accuracy, and is low in cost.

Brief Description of the Drawings

[0010] Figure 1 Schematic diagram of the cable force sensor test device

[0011] Figure 2 This is the full bridge test bridge diagram of the middle ear seat strain sensor of the present invention

[0012] Figure 3 It is the diagram of the three-force equilibrium intersection theorem

[0013] The numbers in the figure refer to: 1-puller upper structure, 2-front connecting rod, 3-counterweight, 4-ear seat, 5-reaction frame, 6-lower pull rod, 7-cable strand, 8-anchor head, 9-upper pull rod, 10-inclination sensor 02, 11-inclination sensor 01, 12-rear connecting rod, 13-horizontal connecting rod. [Specific implementation method]

[0014] The present invention is further described below in conjunction with the accompanying drawings.

[0015] See also Figures 1 to 3 The present invention is a cable force testing technology and device for pulling a cable strand of a puller, including an ear seat strain sensor and an inclination sensor. Figure 1As shown, the ear seat strain sensor and the inclination sensor have been marked at corresponding positions, the upper pull rod 9 and the lower pull rod 6 of the puller are connected to the front link rod 2 and the rear link rod 12 of the puller through the reaction frame 5 and the ear seat 4, and the upper pull rod 9 and the lower pull rod 6 of the puller are fastened to the anchor head 8, so as to pull the rope strand for operation.

[0016] like Figure 1 As shown, the ear seat strain sensor is first described. The resistance strain gauges R1 and R3 are respectively attached to the inner sides of the left and right plates of the ear seat 4 symmetrically along the axial direction of the ear seat. The positions of R1 and R3 are shown in FIG. Figure 1 A view in the middle A direction, and a compensation block made of the same material as the ear seat 4 and without load is set, on which the resistance strain gauges R2 and R4 for temperature compensation are pasted, and R1, R2, R3, and R4 form a full-bridge measurement circuit. The bridge assembly method of the resistance strain gauges R1 to R4 is as follows Figure 2 As shown in the figure, the output signal of the bridge is proportional to the tensile force F on the ear seat 4. Next, the inclination sensor is explained. The inclination sensor 01 and the inclination sensor 02 are arranged along the axis direction of the ear seat 4 and the upper pull rod 9 respectively. The inclination sensor 01 is used to measure the horizontal inclination angle θ1 of the tensile force F on the ear seat. The upper pull rod 9 is consistent with the anchor head 8 along the axis direction. The inclination sensor 02 can be used to measure the horizontal inclination angle θ2 of the traction force T when the puller pulls the cable strand. At the same time, there is the dead weight G of the anchor head 8 and the cable strand 7 during the pulling process. Therefore, if Figure 3 As shown, using the three-force balance theorem, we can get the traction force T = F·cosθ1 / cosθ2 when the puller pulls the cable strand.

Claims

1. A method for testing the traction force of cable strands when erecting the main cable using the PPWS method for a suspension bridge, characterized in that: A technical device for testing the cable strand traction force during main cable installation comprises an ear seat strain sensor and an inclination sensor.

2. The cable strand traction force testing method when installing the main cable of a suspension bridge using the PPWS method according to claim 1 is characterized by: An ear seat strain sensor is provided, and resistance strain gauges R1 and R3 are respectively pasted symmetrically along the axial direction of the ear seat on the inner sides of the left and right plates of the ear seat (4), and a compensation block made of the same material as the ear seat (4) and not bearing any load is provided, on which resistance strain gauges R2 and R4 for temperature compensation are pasted, and R1, R2, R3, and R4 form a full-bridge measurement circuit, and the output signal of the bridge is proportional to the tensile force F exerted on the ear seat (4).

3. The cable strand traction force testing method when installing the main cable of a suspension bridge using the PPWS method according to claim 1 is characterized by: An inclination sensor is provided. An inclination sensor 01 and an inclination sensor 02 are arranged on the ear seat (4) and the upper pull rod (9) respectively along the axial direction. The inclination sensor 01 is used to measure the horizontal inclination angle θ1 of the tensile force F exerted on the ear seat. The upper pull rod (9) is consistent with the anchor head (8) along the axial direction. The inclination sensor 02 can be used to measure the horizontal inclination angle θ2 of the traction force T when the puller pulls the rope strand.

4. The cable strand traction force testing method for erecting the main cable of a suspension bridge using the PPWS method according to claim 1, characterized in that: Using the three-force balance theorem, we can get the precise traction force T = F·cosθ1 / cosθ2 when the puller pulls the cable strand.

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