A method for measuring the elevation of a sea-crossing bridge under a surge environment

Abstract

The present invention discloses a method for measuring the elevation of a cross-sea bridge under a surge environment. A stable measuring station platform is used to measure the elevation of the bridge. The stable measuring station platform includes a shell, a plurality of springs, and a mass block. The mass block is located in the shell, and the spring is fixed to the periphery of the mass block and the inner wall of the shell. The method specifically includes the following steps: S1, setting the frequency ratio of the horizontal vibration frequency of the completed structure to the horizontal vibration frequency of the stable measuring station platform to be ≥3; S2, measuring, based on and, setting; S3, based on the spring stiffness k and, obtaining the mass m of the mass block, based on m, designing the volume of the mass block; S4, assembling the stable measuring station platform, the stable measuring station platform is fixed on the completed structure of the conventional construction of the bridge, and adjusting the damping ratio of the mass block to 0.6≤≤0.7; S5, setting a measuring instrument at the reference point of the mass block, and measuring the bridge elevation by the measuring instrument. The present invention can realize fast and accurate real-time monitoring of offshore elevation, and significantly improve economic efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge construction measurement, and more specifically, to a method for measuring the elevation of a sea-crossing bridge under a surge environment. Background Art

[0002] During the construction of large-scale cross-sea bridges, high-precision cross-sea elevation transfer is required to unify the elevation data on both sides of the bridge and accurately transfer the elevations on both sides to the piers and main beams in the sea, so that the key section elevations of the beams and piers and the main beam line shape after the completion of the bridge meet the design and specification requirements.

[0003] However, cross-sea bridges are generally long, some can reach several kilometers or even tens of kilometers, and traditional leveling methods are difficult to meet the needs of cross-sea elevation transfer measurement. In engineering practice, the elevation control network is generally encrypted by setting up a measurement platform in the sea to shorten the measurement distance. With the continuous advancement of the project, the measurement platform is often set up on the foundation project, such as test piles and some bridge piers completed in advance, which greatly shortens the distance measurement and creates conditions for using the measuring instrument to carry out cross-sea elevation transfer measurement. However, in the actual construction process, affected by factors such as wind, waves, and tides, the measurement platform is always in a slight shaking state under the action of wind and waves, which will inevitably cause the vertical angle of the measuring instrument on the measurement platform to continue to change dynamically, and the change can reach tens of seconds or even minutes. With the rapid advancement of cross-sea projects such as between land and islands and at the mouths of bays and rivers in recent years, the harsh surge environment in deep-sea waters has become more and more significant. For example, the construction of the long-planned three major strait cross-sea channel projects in my country will face a more complex marine environment, and this problem is bound to be more prominent.

[0004] In the past engineering construction process, the main methods to reduce the impact of external wave and current loads (wave and current refer to waves and tides, which are independent of each other) on measurement are: (1) improving the platform stiffness through design, that is, increasing the platform's geometric dimensions to reduce the sway amplitude of the measurement platform. However, actual tests have shown that under the influence of sea conditions such as waves and tides, the maximum sway amplitude of the measurement platform is still more than 100", and the construction cost of the measurement platform is huge; (2) Chinese patent CN104567800B discloses a method based on repeated observations to reduce measurement errors and develops automatic observation recording and data processing software. The system has low measurement efficiency, and its default assumption of "surge as steady fluctuation" is quite different from the actual situation. To ensure the accuracy of the measurement data, it is necessary to conduct long-term observation or select a suitable measurement window period, such as usually at night, which causes obvious interference to the construction; (3) Chinese patent CN106840090B discloses a cross-sea elevation measurement method and system. By analyzing the measurement compliance of each measurement result and encrypting the measurement, relatively accurate measurement results are selected during the measurement process, and it is continuously iterated to ensure that all measurement results meet the measurement requirements. Its measurement efficiency is low and the effect has yet to be verified.

[0005] In summary, the existing land-based measurement methods are no longer applicable to the needs of sea-crossing long bridge elevation measurement during construction under surge conditions, and there are few effective improvement technologies. Therefore, it is necessary to provide a sea-crossing bridge elevation measurement method under surge conditions to solve the technical problems of low measurement accuracy, offshore elevation measurement affected by window periods, and high engineering investment costs due to environmental interference such as surges and strong winds on the measuring station platform. Summary of the invention

[0006] Another object of the present invention is to provide a method for measuring the elevation of a cross-sea bridge in a surge environment, which can realize fast and accurate real-time monitoring of offshore elevation and significantly improve economic efficiency.

[0007] In order to achieve these purposes and other advantages according to the present invention, a method for measuring the elevation of a sea-crossing bridge under a surge environment is provided, wherein a stable measuring station platform is used to measure the elevation of the bridge, wherein the stable measuring station platform comprises a housing, a plurality of springs, and a mass block, wherein the mass block is located in the housing, one end of each of the plurality of springs is symmetrically fixed to the outer periphery of the mass block, and the other end of the spring is fixed to the inner wall of the housing, and the housing is installed on a completed structure of a conventional bridge construction;

[0008] The specific steps include:

[0009] S1. Set the horizontal vibration frequency of the completed structure of the conventional bridge construction Horizontal vibration frequency with stable measuring station platform Frequency ratio ≥3;

[0010] S2. Measure the horizontal vibration frequency of the completed structure of the conventional bridge construction ,based on and ,set up ;

[0011] S3, obtain the stiffness k of the selected spring, based on the spring stiffness k and , obtain the mass m of the mass block, and based on m, design the volume of the mass block, wherein the mass block is a hollow structure;

[0012] S4. Assemble the mass block and spring in the shell to form a stable measuring station platform. Fix the stable measuring station platform on the completed structure of the conventional bridge construction. Add liquid medium into the shell and adjust the damping ratio of the mass block to 0.6≤ ≤0.7;

[0013] S5. Set up the measuring instrument at the reference point of the mass block and measure the elevation of the bridge using the measuring instrument.

[0014] Preferably, the outer shell includes a bottom plate and a plurality of side plates fixedly arranged in the middle of the top surface of the bottom plate, the plurality of side plates are arranged to form a rectangular frame structure, the mass block is arranged in the rectangular frame structure, the two ends of any spring are respectively fixed to the mass block and the corresponding inner wall of the side plate, and the bottom plate is installed on the completed structure of the conventional bridge construction by bolts.

[0015] Preferably, a plurality of stiffening plates are fixedly connected between any side plate and the bottom plate.

[0016] Preferably, the lower end surface of the mass block is fixed to a sliding device, and the sliding device drives the mass block to slide in a horizontal plane.

[0017] Preferably, in step S4, the damping ratio of the mass block is adjusted to satisfy 0.6≤ ≤0.7.

[0018] Preferably, in step S4, a plurality of groups of damping holes are symmetrically opened on the mass block, and damping is generated by the outflow from the damping holes, so as to adjust the damping ratio of the mass block to satisfy 0.6≤ ≤0.7.

[0019] Preferably, in step S4, a rotary damping device is installed in the rectangular frame structure, the rotation frequency of the rotary damping device is controlled, and the damping ratio of the mass block is adjusted to satisfy 0.6≤ ≤0.7.

[0020] Preferably, the mass m of the mass block is calculated by the following formula:

[0021] .

[0022] Preferably, the mass block comprises a body and a top plate, the body is a hollow cube structure, the top plate is welded to the top surface of the body, and the top plate covers the top of the plurality of side plates and does not contact the side plates;

[0023] Preferably, in step S5, the measuring instrument is installed at the reference point through a bracket, the bracket includes a support frame erected at the reference point, and an external mounting seat installed on the support frame, the top surface of the external mounting seat is provided with a hemispherical cavity, the ball head is universally rotatably installed in the hemispherical cavity, a through hole is provided at the bottom of the hemispherical cavity, one end of the pull rod is fixedly connected to the bottom of the ball head, and the other end passes through the through hole to be connected to the inner mounting seat, and the measuring instrument is installed on the inner mounting seat.

[0024] The present invention includes at least the following beneficial effects: the classical theory of inertial displacement meter shows that when the frequency ratio (frequency of the conventionally constructed completed structure / frequency of the stable measuring station platform itself) is ≥3 and the damping ratio is 0.6-0.7, during the vibration of the conventionally constructed completed structure under environmental excitations such as surge and strong wind, the displacement of the mass block in the stable measuring station platform is substantially equal to the displacement of the conventionally constructed completed structure, and the error can be controlled within 1%; therefore, the present application proposes a method for measuring the elevation of a cross-sea bridge under a surge environment, which satisfies the classical theory of inertial displacement meter by setting the frequency ratio and the damping ratio. Theory, so that the stable measuring station platform can adapt to the horizontal vibration of the completed structure of conventional construction, and achieve the horizontal stability of the mass block as the operating end of the stable measuring station platform, so as to greatly reduce or even eliminate environmental interference such as surge and strong wind, so that the subsequent offshore elevation measurement will not be affected by the measurement window period, and it will be able to directly refer to the measurement system on land to achieve fast and accurate real-time monitoring of offshore elevation, efficiently obtain elevation data that meets the measurement accuracy requirements, and significantly improve the economy (reduce project investment), which has great engineering significance for the elevation measurement of long cross-sea bridges during the construction period under surge environment.

[0025] 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

[0026] Figure 1 A schematic diagram of the side structure of a stable measuring station platform according to an embodiment of the present invention;

[0027] Figure 2 is a top view of the stable measuring station platform described in the above embodiment;

[0028] Figure 3 is a schematic diagram of the structure of the bracket described in the above embodiment;

[0029] Description of the Figures in the Specification:

[0030] 1. Outer shell, 101. Bottom plate, 102. Side plate, 2. Spring, 3. Main body, 4. Completed structure of conventional bridge construction, 5. Stiffening plate, 6. Sliding device, 7. Measuring instrument, 8. Top plate, 9. Support frame, 10. External mounting seat, 11. Ball head, 12. Pull rod, 13. Internal mounting seat, 14. Adjusting screw. DETAILED DESCRIPTION

[0031] 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.

[0032] It should be noted that, in the description of the present invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating orientations or positional relationships are 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.

[0033] like Figure 1-3 As shown, the present invention provides a method for measuring the elevation of a sea-crossing bridge under a surge environment, wherein a stable measuring station platform is used to measure the elevation of the bridge, wherein the stable measuring station platform comprises a housing 1, a plurality of springs 2, and a mass block, wherein the mass block is located in the housing 1, one end of each of the plurality of springs 2 is symmetrically fixed to the outer periphery of the mass block, and the other end of the spring 2 is fixed to the inner wall of the housing 1, and the housing 1 is installed on a completed structure 4 of a conventional bridge construction;

[0034] The specific steps include:

[0035] S1. Set the horizontal vibration frequency of the structure 4 completed in the conventional construction of the bridge Horizontal vibration frequency with stable measuring station platform Frequency ratio ≥3;

[0036] S2. Measure the horizontal vibration frequency of the completed structure 4 of the conventional bridge construction ,based on and ,set up , The value of satisfies ≥3 is sufficient;

[0037] S3, obtain the stiffness k of the selected spring 2, based on the stiffness k of spring 2 and , obtain the mass m of the mass block, based on m, design the volume of the mass block and make the mass block. The mass block is a hollow structure, and the mass m of the mass block is calculated by the following formula:

[0038] ;

[0039] S4. Assemble the mass block and spring 2 in the housing 1 to form a stable measuring station platform. Fix the stable measuring station platform on the completed structure 4 of the conventional bridge construction. Add liquid medium into the housing 1. The liquid medium is used to provide a damping ratio. The liquid medium submerges the mass block. Adjust the damping ratio of the mass block to 0.6≤ ≤0.7;

[0040] The damping ratio of the mass block can be adjusted in the following ways:

[0041] 1) By adjusting the viscosity of the liquid medium, the damping ratio of the mass block is adjusted to meet 0.6≤ ≤0.7;

[0042] 2) A plurality of damping holes are symmetrically opened on the mass block, and damping is generated by the outflow from the damping holes to adjust the damping ratio of the mass block to meet 0.6≤ ≤0.7;

[0043] 3) Install a rotary damping device in the rectangular frame structure, control the rotation frequency of the blades of the rotary damping device, and adjust the damping ratio of the mass block to meet 0.6≤ ≤0.7; All the above three methods require experiments in advance to obtain corresponding data;

[0044] S5. Set up the measuring instrument 7 at the reference point of the mass block, and the surveyor stands on the mass block to measure the bridge elevation using the measuring instrument 7.

[0045] In the above technical solution, the classical theory of inertial displacement meter shows that when the frequency ratio (frequency of the conventionally constructed completed structure 4 / frequency of the stable measuring station platform itself) is ≥3 and the damping ratio is 0.6~0.7, during the vibration of the conventionally constructed completed structure 4 under environmental excitations such as surge and strong wind, the displacement of the mass block in the stable measuring station platform is substantially equal to the displacement of the conventionally constructed completed structure 4, and the error can be controlled within 1%; therefore, the present application proposes a method for measuring the elevation of a cross-sea bridge under a surge environment, which satisfies the classical theory of inertial displacement meter by setting the frequency ratio and the damping ratio. , so that the stable measuring station platform can adapt to the horizontal vibration of the completed structure 4 in conventional construction, and achieve the horizontal stability of the mass block as the operating end of the stable measuring station platform, so as to greatly reduce or even eliminate environmental interference such as surge and strong wind, so that the subsequent offshore elevation measurement will not be affected by the measurement window period, and it will be able to directly refer to the measurement system on land to achieve fast and accurate real-time monitoring of offshore elevation, efficiently obtain elevation data that meets the measurement accuracy requirements, and significantly improve the economy (reduce project investment), which has great engineering significance for the elevation measurement construction of long cross-sea bridges during the construction period under surge environment.

[0046] In actual engineering applications, personnel and equipment are placed on a stable measuring station platform (mass block), which is equivalent to increasing the total mass of the mass block, which will improve the frequency ratio. The displacement value of the mass block relative to the reference point becomes smaller, which is conducive to further improving the accuracy of elevation measurement in the project and well meets the actual needs of the project. The present invention can also be used as a measuring point platform at the measuring points of structures such as bridge towers, bridge piers, and cable slings, so that the measuring points (targets) are in a stable state. The combination of the two further improves the measurement accuracy.

[0047] In another technical solution, the shell 1 includes a bottom plate 101 and a plurality of side plates 102 fixedly arranged in the middle of the top surface of the bottom plate 101. The plurality of side plates 102 are arranged to form a rectangular frame structure. The mass block is arranged in the rectangular frame structure. The two ends of any spring 2 are respectively fixed to the mass block and the corresponding inner wall of the side plate 102. The bottom plate 101 is installed on the completed structure 4 of the conventional bridge construction by bolts.

[0048] In another technical solution, a plurality of stiffening plates 5 are fixedly connected between any side plate 102 and the bottom plate 101; the stiffening plates 5 are used to improve the strength and stability of the stable measuring station platform.

[0049] In another technical solution, the lower end surface of the mass block is fixed to the sliding device 6, and the sliding device 6 drives the mass block to slide in a horizontal plane.

[0050] In the present technical solution, in order to ensure the installation stability of the mass block and not affect the movement of the mass block, a sliding device 6 is installed between the lower end surface of the mass block and the top surface of the base plate 101. The sliding device 6 includes a limit plate arranged on the base plate 101, and a plurality of ball bearings rollingly arranged on the limit plate. The plurality of ball bearings are rollingly connected to the cover plate, and the cover plate is welded to the lower end surface of the mass block.

[0051] In another technical solution, the mass block includes a main body 3 and a top plate 8, the main body 3 is a hollow cube structure, the top plate 8 is welded to the top surface of the main body 3, and the top plate 8 covers the top of the plurality of side plates 102 and does not contact the side plates 102.

[0052] In the present technical solution, the top plate 8 of the mass block covers the top of the multiple side plates 102. On the one hand, during the measurement process, if the liquid medium shakes, the top plate 8 can prevent the liquid medium from splashing out; on the other hand, the top plate 8 can increase the range of activities of the measurement personnel, and also prevent the measurement personnel from accidentally falling into the liquid medium, thereby improving the measurement safety. The mass m of the mass block is the sum of the masses of the main body 3 and the top plate 8.

[0053] In another technical solution, in step S5, the measuring instrument 7 is installed at the reference point through a bracket, and the bracket includes a support frame 9 erected at the reference point, and an external mounting seat 10 installed on the support frame 9, and a hemispherical cavity is provided on the top surface of the external mounting seat 10, and a ball head 11 is universally rotatably installed in the hemispherical cavity, and a through hole is provided at the bottom of the hemispherical cavity, one end of the pull rod 12 is fixedly connected to the bottom of the ball head 11, and the other end passes through the through hole to be connected to the inner mounting seat 13, and the measuring instrument 7 is installed on the inner mounting seat 13.

[0054] In this technical solution, if Figure 3As shown, the measuring instrument 7 is installed on the inner mounting seat 13, and the inner mounting seat 13 is connected to the ball head 11 through the pull rod 12, and the ball head 11 is universally rotatably connected to the outer mounting seat 10. During the measurement process, if the measuring instrument 7 is tilted, the measuring instrument 7 can be immediately restored to a vertical state under the action of the adaptive rotation of the ball head 11 and the self-weight of the measuring instrument 7 and the inner mounting seat 13, so that the measuring instrument 7 can be automatically and quickly leveled, thereby ensuring the reliability of the measurement data; the measuring instrument 7 is installed in the inner mounting seat 13, and the bottom of the measuring instrument 7 is connected to the bottom of the inner mounting seat 13 by bolts, and the top surface of the inner mounting seat 13 is provided with an adjusting screw 14, and the bottom of the adjusting screw 14 abuts against the top surface of the measuring instrument 7, and the inner mounting seat 13 can be installed with measuring instruments 7 of different heights through the adjusting screw 14, which has strong applicability.

[0055] 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 method for measuring the elevation of a sea-crossing bridge under a surge environment, characterized in that: A stable measuring station platform is used to measure the bridge elevation. The stable measuring station platform includes a housing, a plurality of springs, and a mass block. The mass block is located in the housing. One end of each of the plurality of springs is symmetrically fixed to the outer periphery of the mass block, and the other end of the spring is fixed to the inner wall of the housing. The housing is installed on a completed structure of conventional bridge construction. The specific steps include: S1. Set the horizontal vibration frequency of the completed structure of the conventional bridge construction Horizontal vibration frequency with stable measuring station platform Frequency ratio ≥3; S2. Measure the horizontal vibration frequency of the completed structure of the conventional bridge construction ,based on and ,set up ; S3, obtain the stiffness k of the selected spring, based on the spring stiffness k and , obtain the mass m of the mass block, and based on m, design the volume of the mass block, wherein the mass block is a hollow structure; S4. Assemble the mass block and spring in the shell to form a stable measuring station platform. Fix the stable measuring station platform on the completed structure of the conventional bridge construction. Add liquid medium into the shell and adjust the damping ratio of the mass block to 0.6≤ ≤0.7; S5. Set up the measuring instrument at the reference point of the mass block and measure the elevation of the bridge using the measuring instrument.

2. The method for measuring the elevation of a sea-crossing bridge under a surge environment as claimed in claim 1, characterized in that: The shell includes a bottom plate and a plurality of side plates fixedly arranged in the middle of the top surface of the bottom plate. The plurality of side plates are arranged to form a rectangular frame structure. The mass block is arranged in the rectangular frame structure. The two ends of any spring are respectively fixed to the mass block and the corresponding inner wall of the side plate. The bottom plate is installed on the completed structure of the conventional bridge construction by bolts.

3. The method for measuring the elevation of a sea-crossing bridge under a surge environment as claimed in claim 2, characterized in that: A plurality of stiffening plates are fixedly connected between any side plate and the bottom plate.

4. The method for measuring the elevation of a sea-crossing bridge under a surge environment as claimed in claim 1, characterized in that: The lower end surface of the mass block is fixed to a sliding device, and the sliding device drives the mass block to slide in a horizontal plane.

5. The method for measuring the elevation of a sea-crossing bridge under a surge environment as claimed in claim 1, characterized in that: In step S4, the damping ratio of the mass block is adjusted to satisfy 0.6≤ ≤0.

7.

6. The method for measuring the elevation of a sea-crossing bridge under a surge environment as claimed in claim 1, characterized in that: In step S4, multiple groups of damping holes are symmetrically opened on the mass block, and damping is generated through the outflow of the damping holes to adjust the damping ratio of the mass block to meet 0.6≤ ≤0.

7.

7. The method for measuring the elevation of a sea-crossing bridge under a surge environment as claimed in claim 2, characterized in that: In step S4, a rotary damping device is installed in the rectangular frame structure, the rotation frequency of the rotary damping device is controlled, and the damping ratio of the mass block is adjusted to satisfy 0.6≤ ≤0.

7.

8. The method for measuring the elevation of a sea-crossing bridge under a surge environment as claimed in claim 1, characterized in that: The mass m of the mass block is calculated by the following formula: 。 9. The method for measuring the elevation of a sea-crossing bridge under a surge environment as claimed in claim 2, characterized in that: The mass block comprises a body and a top plate, wherein the body is a hollow cube structure, the top plate is welded to the top surface of the body, and the top plate covers the top of the plurality of side plates and does not contact the side plates.

10. The method for measuring the elevation of a sea-crossing bridge under a surge environment as claimed in claim 1, characterized in that: In step S5, the measuring instrument is installed at the reference point through a bracket, and the bracket includes a support frame erected at the reference point, and an external mounting seat installed on the support frame. The top surface of the external mounting seat is provided with a hemispherical cavity, and the ball head can be universally rotatably installed in the hemispherical cavity. A through hole is provided at the bottom of the hemispherical cavity, one end of the pull rod is fixedly connected to the bottom of the ball head, and the other end passes through the through hole to be connected to the inner mounting seat, and the measuring instrument is installed on the inner mounting seat.

Images