A net frame underhangs cast-in-place plate inner profile precision measuring device
By combining laser total station, displacement sensor and adjustable support frame, the problems of difficult deformation monitoring and node positioning error in the construction of cast-in-place slabs under space frame are solved, realizing high-precision internal surface control and meeting the needs of high-precision scenarios such as large wind tunnel laboratories.
Patent Information
- Application Number
- CN202522175843.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-15
- Publication Date
- 2026-11-03
- Estimated Expiration
- 2035-10-15
AI Technical Summary
In the construction of cast-in-place slabs under space frames, the extremely small adjustable space of the structure leads to a low rate of deformation error. Space frame deformation caused by multiple factors is difficult to monitor and node positioning errors are difficult to eliminate, affecting the accuracy of the internal surface. This poses a safety hazard, especially in high-precision scenarios such as large wind tunnel laboratories.
A laser total station was used for multi-stage node measurement, and displacement sensors were used to monitor deformation in real time. An adjustable support frame was used to offset the deformation. The construction process was simulated through test pieces to optimize the pre-camber parameters. A data acquisition terminal was used to achieve real-time recording and automatic compensation, thus constructing a closed-loop control system.
It enables precision monitoring of the entire space frame assembly process, avoids the accumulation of local errors, ensures stable distance between steel beams and formwork, meets high-precision design requirements, reduces construction risks, and improves deformation monitoring efficiency and parameter optimization accuracy.
Smart Images
Figure CN224933447U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of wind tunnel space frame construction technology, specifically, it relates to a device for measuring the accuracy of the inner surface of a cast-in-place slab suspended under a space frame. Background Technology
[0002] In the construction of roof structures for large public buildings (such as convention centers and stadiums), industrial plants, and special facilities such as large wind tunnel laboratories, the use of cast-in-place slabs suspended under space frames is becoming increasingly widespread due to their advantages in both load-bearing capacity and space utilization. The core requirement for this type of structure is that the internal surface precision must strictly match the design standards. Especially in scenarios such as large wind tunnel laboratories where airflow and structural flatness are extremely critical, even minute deviations in the internal surface of the cast-in-place slab (such as millimeter-level protrusions or depressions) can affect the overall functionality and even pose safety hazards. In the current technical field, the construction of cast-in-place slabs under space frames faces multiple practical difficulties, which directly lead to difficulties in controlling the accuracy of the internal surface. These difficulties are specifically reflected in the following aspects: Firstly, the structural adjustability is extremely limited, resulting in a low tolerance for deformation control errors. According to engineering practice, the design distance between the lower end of the main steel beam suspended under the roof space frame and the surface of the cast-in-place slab formwork is typically only five centimeters. However, bidirectional bottom reinforcement bars (conventional steel bars with a diameter of 20 mm, occupying a height of 40 mm after installation) are required between the two. This leaves only about 10 mm of actual adjustable space between the steel beam and the formwork. Within this extremely small space, any minute deformation of the space frame (such as deflection or offset) can cause the reinforcement bars to collide with the steel beam or formwork, leading to defects such as bulges and depressions on the inner surface of the cast-in-place slab. Furthermore, due to insufficient adjustability, it is difficult to repair deformation through subsequent adjustments, placing far greater demands on the precision of space frame deformation control than conventional structures. In summary, the construction of cast-in-place slabs under space frames presents several challenges: extremely limited adjustable space leading to a low deformation error rate; difficulty in monitoring space frame deformation caused by multiple factors; and difficulty in eliminating node positioning errors. Utility Model Content
[0003] In view of this, the present invention provides a device for measuring the accuracy of the inner surface of a cast-in-place slab under a space frame, which can solve the problems of low deformation error rate due to extremely small adjustable space, difficulty in monitoring space frame deformation caused by multiple factors, and difficulty in eliminating node positioning errors during the construction of a cast-in-place slab under a space frame.
[0004] This utility model is implemented as follows: This utility model provides a device for measuring the surface accuracy of the inner profile of a cast-in-place slab suspended under a space frame. It includes a laser total station for locating space frame nodes, displacement sensors for monitoring space frame deformation, an adjustable support frame for pre-cambering the space frame, and a test piece for simulating the stress on the space frame. The laser total station is used to locate and measure the space frame assembly nodes, taking measurements after locating a node, assembling a truss, installing a segment, and completing the entire section. The displacement sensors are installed at the lower end of the main steel beam suspended under the space frame to monitor the distance between the steel beam and the surface of the cast-in-place slab template, as well as the deflection deformation of the space frame. Pre-cambering is added in reverse to the height of the support frame to counteract space frame deformation. The test piece is a section of the steel frame simulating a weak point in the space frame, used to compare the actual deformation value after pre-cambering with the finite element simulation value.
[0005] The technical effects of the device for measuring the internal surface accuracy of a cast-in-place slab suspended from a space frame provided by this utility model are as follows: Multi-stage node measurements using a laser total station enable precision monitoring of the entire space frame assembly process, effectively avoiding the accumulation of local errors; real-time monitoring of the distance between the suspended main steel beam and the cast-in-place slab template, as well as the deflection deformation of the space frame, is achieved by setting an adjustable support frame. The pre-camber height is set based on the deflection value generated by the space frame's self-weight and the drop value after concrete pouring, actively offsetting the deformation generated during construction by the space frame's self-weight, ensuring that the geometric configuration of the space frame after forming meets design requirements; test pieces made according to the actual weak sections of the space frame can simulate the actual construction process to verify the pre-camber effect, optimize construction parameters, and reduce risks in actual construction; the overall solution establishes a closed-loop control system of "measurable deformation, pre-controllable deformation, and verifiable effect," preventing the space frame's deflection from exceeding the design allowable range from the source, ensuring that the distance between the steel beam and the template is stably maintained at the design value, and providing a fundamental guarantee for the internal surface accuracy of the cast-in-place slab.
[0006] Based on the above technical solution, the device for measuring the inner surface accuracy of a cast-in-place slab suspended under a space frame according to this utility model can be further improved as follows: The displacement sensor is a laser displacement sensor with a measurement accuracy of not less than 0.1mm, and one is installed every 1.5m along the length of the main steel beam suspended under the space frame.
[0007] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the laser displacement sensor used has a measurement accuracy of 0.1 mm, and one is installed every 1.5 meters along the length of the main steel beam suspended under the grid structure. Through the dense layout design, it can capture the small deformation of the steel beam and achieve monitoring coverage of the entire length of the steel beam. There are no monitoring blind spots, which can effectively avoid the situation where local deformation is not detected in time.
[0008] Furthermore, the adjustable support frame includes a base, a lifting rod, and a top support plate. The lifting rod has scales on its outer side, and the pre-camber value can be precisely controlled by adjusting the height of the lifting rod.
[0009] The beneficial effects of adopting the above-mentioned improved scheme are as follows: The adjustable support frame consists of a base, a lifting rod, and a top support plate. The lifting rod is marked with graduations on its outer side, with the smallest graduation being one millimeter. This graduation allows for precise adjustment of the pre-camber value, with the adjustment error controlled within one millimeter, thus preventing the pre-camber function from failing due to frame height deviation.
[0010] Furthermore, the laser total station is equipped with a temperature compensation module, which can automatically correct measurement errors according to changes in ambient temperature, eliminating the impact of thermal expansion and contraction on node positioning.
[0011] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: The temperature compensation module equipped with the laser total station has an operating temperature range of minus 10 degrees Celsius to 50 degrees Celsius. It can automatically correct the node positioning error according to the change of ambient temperature, eliminating the need for staff to manually calculate and correct the deviation caused by temperature.
[0012] Furthermore, it also includes a data acquisition terminal, which is wirelessly connected to a laser total station and displacement sensors. It can record node positioning data and grid deformation data in real time and generate deformation curves.
[0013] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the data acquisition terminal is connected to the laser total station and displacement sensor wirelessly, which can record node positioning data and grid deformation data in real time, and automatically generate deformation curves; making it easier for staff to quickly determine whether the current deformation exceeds the allowable range.
[0014] Furthermore, the test specimen was made in a 1:1 scale with the actual weak section of the space frame, and bidirectional bottom reinforcement bars of the same specifications as those in the actual project were installed on the test specimen for the space frame under the cast-in-place slab.
[0015] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by making test specimens, the steel reinforcement layout and stress environment of the actual project can be completely simulated, and the consistency between the test results and the actual construction conditions reaches more than 95%, ensuring the effectiveness of the pre-arching parameter optimization.
[0016] Furthermore, the top support plate of the adjustable support frame is equipped with an anti-slip rubber pad at the contact point with the grid node. The rubber pad is 2mm thick to prevent the grid node from sliding and affecting the measurement accuracy.
[0017] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the rubber pad can increase the friction between the frame and the space frame node, so that the sliding amount of the node during the assembly of the space frame or the pouring of concrete is controlled within 0.2 mm, ensuring the stability of the node position.
[0018] Furthermore, the laser total station has a built-in error compensation data storage module, which is used to pre-store the initial error compensation value obtained by computer analysis of error samples, as well as the thermal expansion and contraction calculation values corresponding to different ambient temperatures.
[0019] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: when the total station is performing node positioning, it can automatically call up the data in the module to correct the positioning coordinates, which improves the correction efficiency by 80% compared with manual operation, while avoiding errors that may occur when manually inputting parameters.
[0020] Furthermore, the displacement sensor has a monitoring range of 0~10cm and can simultaneously monitor the distance between the lower end of the main steel beam suspended under the space frame and the formwork of the cast-in-place slab, as well as the deflection of the space frame. The displacement sensor is connected to an alarm.
[0021] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the measurement range of the displacement sensor covers the deformation range that may occur during the construction of the space frame; at the same time, an early warning function is set up. When the detected deformation exceeds 10% of the deflection value of the space frame, the sensor will automatically alarm, allowing the staff enough time to make adjustments and preventing the deformation from further developing into an out-of-tolerance state.
[0022] Furthermore, the test specimen is equipped with an adjustable support frame identical to that used in actual engineering. By adjusting the pre-camber value of the test specimen frame, the deformation offset effect under different pre-camber parameters can be compared to determine the optimal pre-camber value.
[0023] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by installing an adjustable support frame of the same specifications as the actual project on the test piece, and by adjusting the pre-camber value of the frame, three to five sets of comparative tests with different pre-camber parameters can be carried out to analyze the deformation compensation effect under different parameters, quickly screen out the optimal pre-camber value, and the deviation between the optimal value and the finite element simulation value can be controlled within 0.5 mm.
[0024] Compared with existing technologies, the beneficial effects of the device for measuring the internal surface accuracy of cast-in-place slabs under space frames provided by this utility model are as follows: Addressing the problem of extremely limited adjustable space during the construction of cast-in-place slabs under space frames, this utility model employs a laser displacement sensor to monitor the distance between the steel beam and the formwork in real time, combined with an adjustable support frame to precisely set the pre-camber, ensuring deformation is controlled within an adjustable range of 10mm. Facing multi-factor deformation, it uses a laser total station for multi-stage measurement (from single node to the entire section) combined with real-time recording by a data acquisition terminal, achieving deformation monitoring throughout the entire construction stage without omissions or delays. Regarding insufficient pre-camber verification, a 1:1 test specimen is used to compare the effects of different pre-camber parameters, selecting the optimal value with a compensation deviation ≤0.5mm. For node positioning, the total station's built-in error compensation module automatically corrects system and temperature errors, improving efficiency by 80% and eliminating human error. Ultimately, it can control the internal surface accuracy of the cast-in-place slab within design standards, meeting the requirements of high-precision scenarios such as wind tunnel laboratories. Attached Figure Description
[0025] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0026] Fig. 1 A schematic diagram of the construction structure for a device for measuring the accuracy of the inner surface of a cast-in-place slab suspended under a space frame; Fig. 2 This is a schematic diagram of an adjustable support frame structure; Fig. 3 This is a schematic diagram of the deformation of the test specimen under its own weight; The attached diagram lists the components represented by each number as follows: 10. Laser total station; 11. Displacement sensor; 12. Adjustable support frame; 121. Base; 122. Lifting rod; 123. Top support plate; 13. Test piece; 14. Anti-slip rubber pad. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.
[0028] like Figs. 1-3The image shows an embodiment of a device for measuring the surface accuracy of a cast-in-place slab suspended under a space frame, provided by this utility model. This embodiment includes a laser total station 10 for locating space frame nodes, a displacement sensor 11 for monitoring space frame deformation, an adjustable support frame 12 for pre-cambering the space frame, and a test piece 13 for simulating the stress on the space frame. The laser total station is used to locate and measure the space frame assembly nodes, performing measurements after locating a node, assembling a section, installing a segment, and completing the entire section. The displacement sensor is installed at the lower end of the main steel beam suspended under the space frame to monitor the distance between the steel beam and the surface of the cast-in-place slab template, as well as the deflection deformation of the space frame. Pre-cambering values are added in reverse to the height of the support frame to counteract space frame deformation. The test piece is a section of steel frame structure simulating a weak point in the space frame, used to compare the actual deformation value after pre-cambering with the finite element simulation value.
[0029] The height of the adjustable support frame is calculated and determined based on the deflection value h mm of the grid frame's self-weight and the drop value after concrete pouring.
[0030] Preferably, the design distance between the steel beam and the formwork is 5cm, which can capture deformation data in time to prevent deviations.
[0031] In the above technical solution, the displacement sensor is a laser displacement sensor with a measurement accuracy of not less than 0.1mm, and one is installed every 1.5m along the length of the main steel beam suspended under the space frame.
[0032] Furthermore, in the above technical solution, the adjustable support frame includes a base 121, a lifting rod 122 and a top support plate 123. The lifting rod has a scale on its outer side, and the pre-arch value can be precisely controlled by adjusting the height of the lifting rod.
[0033] Furthermore, in the above technical solution, the laser total station is equipped with a temperature compensation module, which can automatically correct measurement errors according to changes in ambient temperature and eliminate the impact of thermal expansion and contraction on node positioning.
[0034] Furthermore, the above technical solution also includes a data acquisition terminal, which is wirelessly connected to a laser total station and displacement sensors. It can record node positioning data and grid deformation data in real time and generate deformation curves.
[0035] Furthermore, in the above technical solution, the size of the test piece is made at a 1:1 scale with the actual weak section of the space frame, and the test piece is fitted with bidirectional bottom reinforcement bars of the same specifications as the cast-in-place slab under the space frame in the actual project.
[0036] Furthermore, in the above technical solution, the top support plate of the adjustable support frame is provided with an anti-slip rubber pad 14 at the contact point with the grid node. The rubber pad is 2mm thick to prevent the grid node from sliding and affecting the measurement accuracy.
[0037] Furthermore, in the above technical solution, the laser total station has a built-in error compensation data storage module, which is used to pre-store the initial error compensation value obtained by computer analysis of error samples and the thermal expansion and contraction calculation values corresponding to different ambient temperatures.
[0038] The ambient temperature range is -10℃ to 50℃.
[0039] Furthermore, in the above technical solution, the displacement sensor has a monitoring range of 0~10cm, and can simultaneously monitor the distance between the lower end of the main steel beam suspended under the space frame and the cast-in-place slab formwork, as well as the deflection of the space frame. The displacement sensor is connected to an alarm.
[0040] The alarm will sound when the deformation exceeds the preset value (10% of h mm).
[0041] Furthermore, in the above technical solution, the test piece is equipped with an adjustable support frame identical to that in actual engineering. By adjusting the pre-camber value of the test piece frame, the deformation offset effect under different pre-camber parameters can be compared to determine the optimal pre-camber value.
[0042] Specifically, the principle of this utility model is as follows: a monitoring, compensation, and verification system is constructed through the coordinated structure of the overall measuring device. First, components are prepared according to construction requirements. A laser total station with temperature compensation and error storage modules is used to automatically correct errors by locating the grid nodes from single nodes to each truss and finally to the entire section. Displacement sensors are installed on the steel beams, triggering an alarm when deformation exceeds 10%h. Based on the grid deflection value, a graduated adjustable support frame is used to reverse the pre-camber setting, with anti-slip rubber pads ensuring node stability. A 1:1 test specimen is fabricated, and the pre-camber effect is tested using the matching support frame. The data acquisition terminal wirelessly aggregates data to generate curves to guide adjustments. The coordinated operation of all components achieves measurable deformation, precise compensation, and verifiable effects, ensuring the accuracy of the cast-in-place slab's internal surface.
Claims
1. A device for measuring the accuracy of the inner surface of a cast-in-place slab suspended under a space frame, characterized in that, The system includes a laser total station for locating space frame nodes, displacement sensors for monitoring space frame deformation, an adjustable support frame for pre-cambering the space frame, and test specimens for simulating the stress on the space frame. The laser total station is used to locate and measure the space frame assembly nodes, taking measurements after locating a node, assembling a frame, installing a segment, and completing the entire section. The displacement sensors are installed at the lower end of the main steel beams suspended from the space frame to monitor the distance between the steel beams and the surface of the cast-in-place slab formwork, as well as the deflection deformation of the space frame. Pre-cambering values are added in reverse to the height of the support frame to counteract space frame deformation. The test specimens are steel frame structures simulating weak points in the space frame, used to compare the actual deformation values after pre-cambering with the finite element simulation values.
2. The device for measuring the accuracy of the inner surface of a cast-in-place slab suspended under a space frame according to claim 1, characterized in that, The displacement sensor is a laser displacement sensor with a measurement accuracy of not less than 0.1mm, and one is installed every 1.5m along the length of the main steel beam suspended under the space frame.
3. The device for measuring the inner surface accuracy of a cast-in-place slab suspended under a space frame according to claim 2, characterized in that, The adjustable support frame includes a base, a lifting rod, and a top support plate. The lifting rod has scales on the outside, and the pre-camber value can be precisely controlled by adjusting the height of the lifting rod.
4. The device for measuring the inner surface accuracy of a cast-in-place slab suspended under a space frame according to claim 3, characterized in that, The laser total station is equipped with a temperature compensation module, which can automatically correct measurement errors according to changes in ambient temperature and eliminate the impact of thermal expansion and contraction on node positioning.
5. The device for measuring the inner surface accuracy of a cast-in-place slab suspended under a space frame according to claim 4, characterized in that, It also includes a data acquisition terminal, which is wirelessly connected to a laser total station and displacement sensors. It can record node positioning data and grid deformation data in real time and generate deformation curves.
6. The device for measuring the inner surface accuracy of a cast-in-place slab suspended under a space frame according to claim 5, characterized in that, The test specimen was made in 1:1 scale with the actual weak section of the space frame, and the test specimen was fitted with bidirectional bottom reinforcement bars of the same specifications as the cast-in-place slab under the space frame in the actual project.
7. The device for measuring the inner surface accuracy of a cast-in-place slab suspended under a space frame according to claim 6, characterized in that, The top support plate of the adjustable support frame is equipped with an anti-slip rubber pad at the contact point with the grid node. The rubber pad is 2mm thick to prevent the grid node from sliding and affecting the measurement accuracy.
8. The device for measuring the inner surface accuracy of a cast-in-place slab suspended under a space frame according to claim 7, characterized in that, The laser total station has a built-in error compensation data storage module, which is used to pre-store the initial error compensation value obtained by computer analysis of error samples, as well as the thermal expansion and contraction calculation values corresponding to different ambient temperatures.
9. A device for measuring the accuracy of the inner surface of a cast-in-place slab suspended under a space frame, as described in claim 8, is characterized in that... The displacement sensor has a monitoring range of 0~10cm and can simultaneously monitor the distance between the lower end of the main steel beam suspended under the space frame and the formwork of the cast-in-place slab, as well as the deflection of the space frame. The displacement sensor is connected to an alarm.
10. A device for measuring the accuracy of the inner surface of a cast-in-place slab suspended under a space frame, as described in claim 9, is characterized in that... The test specimen is equipped with an adjustable support frame identical to that used in actual engineering. By adjusting the pre-camber value of the test specimen frame, the deformation offset effect under different pre-camber parameters can be compared to determine the optimal pre-camber value.