A method for measuring locking stress of highly modular steel truss structures

Abstract

The present invention discloses a method for measuring locking stress of a highly modular steel truss structure, including determining a module rod for which locking stress measurement is to be performed; determining the arrangement of sensors in a stress-temperature measurement and acquisition system; installing a stress-temperature measurement and acquisition system and an environmental meteorological monitoring system in a loose-rod state at the stage of the module rod leaving the factory, measuring stress-temperature data from a zero stress state, and uploading the data to a data cloud platform; the stress-temperature measurement and acquisition system and the environmental meteorological monitoring system continuously collect stress-temperature data throughout the entire process, and uploading the data to a data cloud platform; calculating and eliminating the influence of structural temperature stress and the semi-rigid node effect of the truss structure, and obtaining the locking stress measurement result of the module rod. The present invention monitors the entire process of the component from the time of leaving the factory, and performs temperature stress correction and semi-rigid node correction through sensor arrangement and temperature field monitoring, and obtains the locking stress measurement result of the key rod position.

Description

Technical Field

[0001] The invention relates to the technical field of steel truss structure construction monitoring, and in particular to a locking stress measurement method for a highly modular steel truss structure. Background Art

[0002] Industrialization and modularization are the mainstream development directions of the construction industry. Modular buildings and prefabricated buildings have become important development directions for structural engineering. Steel truss structures are naturally suitable for modular structure installation because of their clear force form, simple construction measures, and structural characteristics that can be connected using high-strength bolts.

[0003] The modular steel truss structure first pre-processes the structural rods into piece trusses, forms an integral truss box in the on-site assembly stage, and hoists the truss box onto the frame to assemble it into a module. In the stage where the whole is not formed, the professional construction of the ceiling, water, electricity, curtain wall, etc. is integrated, and it is transported to the site in the form of a comprehensive module for patching and splicing to form the final structure. Considering that the modular steel truss structure has a short construction period, high component quality, low environmental pollution, low management cost, and is very suitable for construction projects with limited construction sites, this construction method has gradually been developed and applied.

[0004] However, the highly modular steel truss structure has a more significant "locking stress" problem than the traditional steel truss structure. During the manufacturing and installation process, the equipment and structural components will be affected by external forces, temperature changes and other factors, resulting in internal stress. These stresses are retained after the structural construction is completed, forming the so-called "locking stress". The sources of locking stress mainly include forced structural deformation and temperature changes. During the manufacturing and assembly process, structural components may have deformations such as bending and torsion, which will then form defects such as installation gaps, local angular deformations, and rod misalignment, resulting in internal locking stress after the construction is completed. In terms of temperature changes, during the processing and assembly of metal structures, materials in different areas may generate thermal stress due to temperature changes. When the temperature field changes after the construction is completed, the thermal stress will be retained in the material to form locking stress. For example, the steel truss structure is affected by solar radiation or ambient temperature, resulting in temperature changes. When the radiation and ambient temperature states change after the construction is completed, the temperature effect will be converted into locking stress.

[0005] Traditional steel truss structures are generally installed by loosely assembling rods. The rods are assembled in a stress-free state and lifted with the structure as a whole. Highly modular steel trusses may generate large locking stresses during the formation of the structure due to factors such as the many intermediate steps in the assembly process and the introduction of loads from other disciplines. In addition, in addition to structural disciplines, modular steel truss structures also integrate water, electricity, ceiling and other disciplines. This further brings about the problem of secondary stress on the structure while also causing locking stresses and stress changes in non-structural components such as purlins.

[0006] The locking stress of highly modular structures is mainly caused by the following factors: (1) Insufficient precision of structural assembly segments leads to forced installation. For traditional steel truss structures, the members are assembled in a loose state, and the cumulative effect of member manufacturing errors can be compensated by inserting and patching positions. However, since the truss boxes of highly modular steel structures are assembled in advance, they are often forcibly installed by pulling or other methods in the case of insufficient precision, which introduces locking stress in the structure after installation. (2) Locking stress is introduced during the long-distance transportation of the structure. Unlike traditional steel truss structures that are fully assembled on site, highly modular steel truss structure construction is often used in project contexts with limited construction site work space. Therefore, in addition to the component processing site and the actual project site, it is often necessary to add a "second site" as the construction site. The component processing site manufactures steel structure members, and the members are spliced ​​at the second site to form related secondary structures such as the main truss or secondary truss. The secondary structure is hoisted at the second site and spliced ​​again to form the entire module. The entire module is hoisted again and transported to the site by vehicle / ship. At the site, each module is lifted and spliced ​​to form the overall building structure. During this process, there may be factors such as transportation bumps, collisions, and support conversions, which will introduce stress into the structure and permanently lock it after the overall assembly, causing secondary or even multiple stress problems.

[0007] Therefore, formulating a reasonable locking stress measurement scheme for highly modular steel truss structures is the key to ensuring high-quality construction of highly modular steel truss structures. However, the existing steel truss structure monitoring cases have not yet achieved the full process monitoring of the locking stress of the rods of highly modular construction steel truss structures. How to accurately measure the locking stress of highly modular steel truss structures and eliminate the influence of temperature stress and semi-rigid effect of truss structure nodes while measuring the locking stress has become a technical problem that needs to be solved urgently. Summary of the invention

[0008] The purpose of the present invention is to provide a method for measuring locking stress of a highly modular steel truss structure to solve the technical problems described in the background technology.

[0009] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0010] A method for measuring locking stress of a highly modular steel truss structure comprises the following steps:

[0011] Step S1, determining the module rods to be subjected to locking stress measurement according to the structural force transmission mode and construction plan of the design model;

[0012] Step S2, determining the spatial position arrangement scheme of each sensor in the stress-temperature measurement and acquisition system according to the properties of the module rod for which the locking stress measurement is to be performed;

[0013] Step S3, installing a stress-temperature measurement and acquisition system and an environmental meteorological monitoring system in the loose-rod state of the module rods at the factory stage, measuring stress-temperature data from a zero stress state, and uploading the data to a data cloud platform;

[0014] Step S4, the stress-temperature measurement and acquisition system and the environmental meteorological monitoring system are transported synchronously with the module rods or steel truss modules. During the modular construction, the stress-temperature measurement and acquisition system and the environmental meteorological monitoring system are regularly maintained so that the stress-temperature measurement and acquisition system and the environmental meteorological monitoring system continuously collect stress and temperature data throughout the entire process, and upload them to the data cloud platform to completely monitor the entire process of steel structure assembly, loading and transportation, truss box ground assembly, lifting, steel truss module structure formation, steel truss module multi-professional integration, transportation to the site, lifting slide rails, rail drop unloading, and structural gap filling;

[0015] Step S5, calculate and eliminate the influence of structural temperature stress and the semi-rigid node effect of the truss structure, and obtain the locking stress measurement results of the module rods.

[0016] Preferably, the stress-temperature measurement and acquisition system includes a vibrating-wire strain gauge, a temperature sensor, a data cable and a collector. The vibrating-wire strain gauge and the temperature sensor are both arranged on the module rod for locking stress measurement. At least one collector is fixed on each module rod for locking stress measurement. The collector is connected to the data cloud platform for communication and uploads the collected data to the data cloud platform. All vibrating-wire strain gauges and temperature sensors arranged on the same module rod as the collector are connected to the collector via data cables.

[0017] The environmental meteorological monitoring system includes a meteorological station, which is installed in a location near the steel truss module with smooth ventilation and no sunlight obstruction, and is used to measure and collect environmental temperature and humidity, solar radiation and environmental wind speed data, and upload the collected data to a data cloud platform.

[0018] Preferably, the modular rods to be subjected to locking stress measurement include modular rods of main stresses that control the structural design during the structural design phase or whose stress changes significantly during the construction phase, and modular rods of auxiliary structures in steel truss modules.

[0019] Preferably, the stress-temperature measurement and acquisition system has two settings. When the module rod to be subjected to locking stress measurement is the main stress-bearing module rod, the vibrating-wire strain gauge needs to be arranged at least at two different cross-sectional positions of the module rod, and one of the cross-sectional positions is located at the mid-span position of the module rod. At least four vibrating-wire strain gauges are arranged at the same cross-sectional position. The vibrating-wire strain gauges at the same cross-sectional position are arranged in a circular array, and the arrangement positions of the vibrating-wire strain gauges at different cross-sectional positions correspond to each other. The temperature sensor needs to be arranged at least at the mid-span cross section of the module rod, and at least four temperature sensors are arranged at the same cross-sectional position.

[0020] When the modular rod to be subjected to locking stress measurement is a modular rod of an accessory structure, it is only necessary to set a vibrating wire strain gauge and a temperature sensor at the mid-span position of the modular rod.

[0021] Preferably, the vibrating-wire strain gauge and temperature sensor on the same module rod share a data collector, which includes an equipment power supply module, a signal receiving module, a data calculation module and a communication module. The power supply module is responsible for providing equipment power support for the data collector. The signal receiving module is connected to the vibrating-wire strain gauge and the temperature sensor via a data cable, and is used to receive the digital signal transmitted by the data cable. The data calculation module calculates the collected digital signal into a monitoring data result. The communication module is connected to the data cloud platform for communication, and uploads the calculation result of the data calculation module to the data cloud platform.

[0022] Preferably, after the installation of the vibrating-wire strain gauge, temperature sensor and collector, a protective shell is used for external protection, and the data cable is encapsulated and protected with a protective tube. There are two types of protective tubes for the data cable. PVC tubes are used for protection in straight-line routing positions, and plastic hoses are used for protection in bending areas.

[0023] Preferably, the vibrating-wire strain gauge and the temperature sensor are fixed to the surface of the rod in a loose-rod state after the module rod is processed. The vibrating-wire strain gauge is fixed by welding or by gluing with casting glue, and the temperature sensor is installed and fixed by gluing.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention adopts vibrating-wire strain gauges, platinum resistance temperature sensors and comprehensive monitoring technology of meteorological stations to monitor the entire process of components from the time they are processed and shipped out of the factory, and performs temperature stress correction and semi-rigid node correction through sensor arrangement and temperature field monitoring to obtain locking stress measurement results of key rod positions. During the construction phase, the measurement results can guide risk control during the construction process, and make construction adjustments for areas with obvious abnormalities. During the operation and maintenance phase, the measurement structure can supplement the initial locking stress on the basis of the original design model, and re-judge and evaluate the safety and normal use capacity of the structure under long-term effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or other aspects and advantages of the present invention will become clearer and easier to understand through the detailed description made in conjunction with the following drawings, which are only exemplary and do not limit the present invention, wherein:

[0026] Figure 1 It is a schematic diagram of a highly modular steel truss structure locking stress measurement system according to the present invention;

[0027] Figure 2 It is a structural schematic diagram of the sensor of the stress-temperature measurement and acquisition system according to the present invention when arranged in the cross section of an I-beam;

[0028] Figure 3 It is a structural schematic diagram of the sensor of the stress-temperature measurement and acquisition system according to the present invention when arranged in a square steel pipe cross section;

[0029] Figure 4 The present invention is a schematic diagram of the structure of the sensors of the stress-temperature measurement and acquisition system when arranged in the cross section of a circular steel pipe.

[0030] Figure numerals: 1. Steel truss module; 2. Module rod; 3. Data cloud platform; 4. Stress-temperature measurement and acquisition system; 5. Environmental meteorological monitoring system. DETAILED DESCRIPTION

[0031] Hereinafter, an embodiment of a highly modular steel truss structure locking stress measurement method of the present invention will be described with reference to the accompanying drawings. The embodiments described herein are specific embodiments of the present invention, which are used to illustrate the concept of the present invention. They are all explanatory and exemplary and should not be interpreted as limiting the embodiments of the present invention and the scope of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in the claims and the specification of this application, including technical solutions that adopt any obvious replacements and modifications to the embodiments described herein.

[0032] In the description of the present invention, it should be noted that the terms "front", "rear", "left", "right", "top", "bottom", "up", "down", "inside", "outside", "horizontal", "vertical", "upright", "oblique", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying 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 limiting the present invention. In addition, the terms "first", "second", etc., are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0033] The drawings of this specification are schematic diagrams, which assist in explaining the concept of the present invention and schematically show the shapes of various parts and their mutual relationships. Please note that in order to clearly show the structures of various components of the embodiments of the present invention, the drawings are not drawn according to the same scale. The same reference numerals are used to represent the same parts.

[0034] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The embodiments are only used to explain the present invention and are not used to limit the scope of the present invention. Figure 1-4 , the preferred embodiments of the present invention are further described in detail: Figure 1As shown, a preferred highly modular steel truss structure locking stress measurement system of the present invention includes a stress-temperature measurement and acquisition system 4, an environmental meteorological monitoring system 5 and a data cloud platform 3, wherein the stress-temperature measurement and acquisition system 4 includes a vibrating-wire strain gauge, a temperature sensor, a data cable and a collector, wherein the vibrating-wire strain gauge and the temperature sensor are both arranged on the module rod 2 for locking stress measurement, and the vibrating-wire strain gauge and the temperature sensor are fixed to the rod surface in the loose rod state after the module rod 2 is processed. Normally, the vibrating-wire strain gauge is fixed to the surface of the module rod 2 by welding. For some module rods 2 with special requirements for surface coating, the vibrating-wire strain gauge needs to be fixed by casting glue, and the temperature sensor is installed and fixed by pasting. The collector is connected to the data cloud platform 3 for communication, and the collected data is uploaded to the data cloud platform 3. All vibrating-wire strain gauges and temperature sensors arranged on the same module rod 2 as the collector are connected to the collector by data cables. Specifically, The collector includes an equipment power supply module, a signal receiving module, a data calculation module and a communication module. The power supply module is responsible for providing equipment power support for the collector, which can be achieved by connecting to construction electricity, arranging batteries or connecting solar panels. The signal receiving module is connected to the vibrating wire strain gauge and the temperature sensor through a data cable, and is used to receive the digital signal transmitted by the data cable. The data calculation module needs to input the factory calibration result of the sensor in advance, and calculate the collected digital signal as the monitoring data result. The communication module is connected to the data cloud platform 3 for communication, and the calculation result of the data calculation module is uploaded to the data cloud platform 3. Since the vibrating wire strain gauge and the temperature sensor need to be installed in a loose rod state, the collectors matched with the two cannot be used between different rods. For this reason, at least one collector is fixed on each module rod 2 for locking stress measurement. From the perspective of reducing costs and increasing efficiency, the vibrating wire strain gauge and the temperature sensor on the same module rod 2 can share one collector;

[0035] The environmental meteorological monitoring system 5 includes a meteorological station, which is installed at a location near the steel truss module 1 where ventilation is smooth and there is no sunlight obstruction. It includes a power supply module, a temperature and humidity measurement module, a wind force and wind speed measurement module, a sunshine radiation measurement module and a communication module, which are used to measure and collect environmental temperature and humidity, sunshine radiation and environmental wind speed data, and upload the collected data to the data cloud platform 3. The meteorological station is installed at the same time as the stress-temperature measurement and acquisition system 4. The meteorological station is set up in each site, and the meteorological station is transported synchronously with the steel truss module 1 to achieve full-process monitoring. The power supply module of the meteorological station is responsible for providing equipment power support for the meteorological station, which can be achieved by connecting construction electricity, arranging batteries or connecting solar panels. The temperature and humidity measurement module is used to measure the changes in the ambient temperature and humidity of the site. The humidity measurement module is often combined with the temperature measurement module. The wind force and wind speed measurement module is used to measure the wind speed of the site. The wind speed will affect the convective heat transfer coefficient of the structure surface, thereby affecting the model calculation results. The sunshine radiation measurement module is used to measure the sunshine radiation received by the horizontal surface of the site and calibrate the sunshine radiation calculation model (generally using the Duffie model);

[0036] Taking into account the different functions of various module rods 2 in the steel truss module 1, the stress-temperature measurement and acquisition system 4 has two settings. When the module rod 2 to be measured for locking stress is the main stress-bearing module rod 2, the vibrating wire strain gauge must be arranged at least at two different cross-sectional positions of the module rod 2, and one of the cross-sectional positions is located at the mid-span position of the module rod 2. At least four vibrating wire strain gauges are arranged at the same cross-sectional position, and the vibrating wire strain gauges at the same cross-sectional position are arranged in a circular array, and the arrangement positions of the vibrating wire strain gauges at different cross-sectional positions correspond to each other. The temperature sensor must be arranged at least at the mid-span cross section of the module rod 2, and at least four temperature sensors are arranged at the same cross-sectional position; when the module rod 2 to be measured for locking stress is the module rod 2 of the auxiliary structure, only one vibrating wire strain gauge and one temperature sensor need to be arranged at the mid-span position of the module rod 2;

[0037] Since the entire system needs to be monitored throughout the entire process, the vibrating-wire strain gauge, temperature sensor and collector need to be protected with a protective shell after installation. The data cable is encapsulated and protected with a protective tube. There are two types of protective tubes for the data cables. PVC tubes are used for protection in straight-line routing positions, and plastic hoses are used for protection in bending areas, so that the monitoring equipment can be protected for a long time to avoid accidental damage during the construction process.

[0038] In addition, the present invention also provides a measurement method for the above-mentioned highly modular steel truss structure locking stress measurement system, comprising the following steps:

[0039] Step S1, according to the structural force transmission mode and construction plan of the design model, determine the module rods 2 to be subjected to locking stress measurement, wherein the module rods 2 to be subjected to locking stress measurement include the main force-bearing module rods 2 that control the structural design in the structural design stage or that have significant stress changes in the construction stage (generally, the upper and lower chords at the mid-span position of the structure, the upper and lower chords near the support when there is a temporary support position conversion condition during the construction process, and the module rods 2 of the auxiliary structures such as the roof purlins in the steel truss module 1;

[0040] Step S2, according to the properties of the module rod 2 to be measured for locking stress, determine the spatial position layout of each sensor in the stress-temperature measurement and acquisition system 4 to meet the temperature-stress multi-dimensional monitoring needs. Since the semi-rigid node effect is coupled with the temperature effect, in order to realize the temperature effect measurement considering the semi-rigid effect of the node, it is necessary to arrange sensors (vibrating wire strain gauges and temperature sensors) on at least two module rods 2 in different directions (non-parallel). If it is necessary to additionally consider the influence of the pulling of the rods during the construction process, more rods need to be measured. For each additional rod that is affected by human factors such as forced pulling during the construction process, one more rod needs to be measured. The sensors are vibrating wire strain gauges and PT100 platinum resistance temperature sensors. The locking stress measurement requires measuring the entire construction process of the modular results of the rods from the factory. The above-mentioned type of sensors has high data accuracy and reliable measurement principles, and are suitable for long-term monitoring and measurement. At the same cross-sectional position of the rod 2, the more sensors are arranged, the higher the monitoring accuracy will be. However, from an economic point of view, for the main force-bearing module rod 2 in the steel truss module 1, at least eight vibrating-wire strain gauges and four PT100 temperature sensors are required to be arranged. The arrangement of the sensors is as follows: the eight vibrating-wire strain gauges are arranged at the cross-sections at two different positions of the module rod 2, with four arranged in each cross-section. One of the cross-sections is at the mid-span position of the module rod 2, and the other cross-section can be determined according to the actual project situation. It is recommended to arrange it at the 1 / 4 length position of the module rod 2. Four PT100 platinum resistance temperature sensors are arranged at the same position as the vibrating-wire strain gauges at the mid-span cross-section of the module rod 2. When the installation conditions are met, the distance between the temperature sensor acquisition end and the vibrating-wire strain gauge mounting bracket shall not exceed 5 cm. The specific arrangement position of the sensor needs to be determined according to the cross-sectional form of the module rod 2, such as Figure 2-4 As shown, for the modular rods 2 in the form of square steel tubes and round steel tubes, the sensors should be arranged on the surface in four directions; for the modular rods 2 in the form of I-beams, the sensors should be arranged on both sides of the upper and lower flanges of the rods; for the modular rods 2 of the auxiliary structures such as purlins in the steel truss module 1 that are not the main force-bearing, a vibrating wire strain gauge and a PT100 temperature sensor can be installed at the mid-span cross section of the modular rod 2;

[0041] Step S3, installing the stress-temperature measurement and acquisition system 4 and the environmental meteorological monitoring system 5 in the loose state of the module rod 2 at the factory stage, measuring the stress temperature data from the zero stress state, and uploading it to the data cloud platform 3;

[0042] Step S4, the stress-temperature measurement and acquisition system 4 and the environmental meteorological monitoring system 5 are transported synchronously with the module rods 2 or the steel truss modules 1. During the modular construction, the stress-temperature measurement and acquisition system 4 and the environmental meteorological monitoring system 5 are regularly maintained (for example, the battery of the collector is regularly replaced), so that the stress-temperature measurement and acquisition system 4 and the environmental meteorological monitoring system 5 continuously collect stress and temperature data throughout the whole process, and upload them to the data cloud platform 3, and completely monitor the whole process of steel structure assembly, loading and transportation, truss box ground assembly, lifting, steel truss module 1 structure formation, steel truss module 1 multi-professional integration, transportation to the site, lifting slide rails, rail unloading, and structural gap filling. During this period, the time of key structural operations is recorded and compared with the monitoring data for analysis;

[0043] Step S5, calculate and eliminate the influence of structural temperature stress and the semi-rigid node effect of the truss structure, and obtain the locking stress measurement result of the module rod 2. Due to the semi-rigid effect of the node, the force on the rod is not pure tension or pure compression. Four sensors were arranged at different cross-sectional positions on the cross section during the early stage of sensor arrangement. Therefore, based on the flat cross-section assumption, the average value of the four sensor data can be used as the axial force of the rod. The local curvature of the cross section in the direction is determined according to the sensor stress difference in the corresponding direction of the front and rear two groups of cross-sectional positions, and then the bending moment in the direction is determined, so that the axial force in the axial force-bending moment coupling effect caused by the semi-rigid node can be In the data results obtained by monitoring, some stress results are affected by daily temperature changes and solar radiation, showing a significant daily change pattern. Therefore, it is necessary to eliminate the influence of temperature effect in the data results. To this end, the temperature field of the module structure under solar radiation can be simulated using the meteorological station measurement data. The temperature results are used to verify the temperature gradient of the module rod 2 using the PT100 temperature sensor measurement results at different positions of the rod. The axial force caused by the overall temperature change of the module rod 2 and the bending moment caused by the temperature gradient are eliminated. After eliminating the above two influencing factors, the locking stress monitoring results can be finally obtained.

[0044] After obtaining the temperature of the module rod 2 collected by the PT100 temperature sensor and the ambient temperature and humidity, solar radiation and ambient wind speed data collected by the meteorological station, the solar radiation received by each module rod 2 can be calculated through the solar radiation model. The actual temperature T of each module rod 2 can be calculated by combining the ambient temperature and the convection heat transfer coefficient. The calculation method refers to the following formula:

[0045]

[0046] q=h(TT a )-G t (2)

[0047] Where, T is the temperature field function; λ is the thermal conductivity; ρ is the density; c is the specific heat capacity; Φ is the internal heat source intensity of the structure (generally 0 for steel structures); q is the surface heat flux density of the structure, h is the surface heat transfer coefficient, Ta is the ambient temperature, and Gt is the solar radiation heat flux density absorbed by the structure.

[0048] Since the semi-rigid node effect is coupled with the temperature effect, the calculation method considering the coupling of the semi-rigid node effect and the temperature effect is as follows: the internal force of each modular rod 2 is N, and the bending moments at both ends are M1 and M2. Since there is no load on the modular rod 2, the bending moment in the modular rod 2 changes linearly. Therefore, the internal force of the entire truss composed of n modular rods 2 can be expressed by the n*3 matrix F. The steel truss structure has m nodes, so the load (stress load, ignoring the influence of temperature) can be expressed by the m*3 matrix L. The temperature field of the node can be expressed by the n*1 matrix Tn, where the subscript n is the abbreviation of node, indicating the temperature value calculated at each node by equations (1)-(2). The semi-rigid effect of the node is expressed by parameters Ka and Kb.

[0049] In the original design model, the temperature effect is not considered, and it is assumed that all nodes are purely hinged nodes, and there is an overall structural internal force F0 (L) at a certain construction stage;

[0050] The temperature of module member 2 calculated by formula (1)-(2) is applied to the ideal model without considering the semi-rigid node effect, and the internal force obtained is F1(L,Tn);

[0051] Taking into account the temperature calculation results of the nodes and the semi-rigid node effects, the internal force obtained first is F3 (L, Tn, Ka, Kb). At the same time, the actual internal force of some members of the structure has been measured by sensors, and the measurement result is f. The data of the corresponding monitoring members in F3 are sliced ​​to obtain the theoretical calculation result F', and the unknown quantities Ka and Kb are optimized to minimize the norm of the subtraction result of the two matrices ||f-F'||, thereby obtaining Ka and Kb. Then, Ka and Kb are substituted into F3 (L, Tn, Ka, Kb) to obtain the internal force distribution of the entire structure.

[0052] Without considering the temperature effect, but considering the semi-rigid node effect, the internal force obtained is F2(L,Ka,Kb);

[0053] (F1-F0) is the effect of temperature considered alone;

[0054] (F2-F0) is the effect of semi-rigid nodes only considered;

[0055] The result obtained by (F3-F0)-(F2-F0)-(F1-F0) is the effect corresponding to the coupling between the two.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for measuring locking stress of a highly modular steel truss structure, characterized in that: The steps include: Step S1, determining the module rods (2) to be subjected to locking stress measurement according to the structural force transmission mode of the design model and the construction plan, wherein the module rods (2) to be subjected to locking stress measurement include the module rods (2) that are mainly subjected to stress and control the structural design in the structural design stage or that have significant stress changes in the construction stage, and the module rods (2) of the auxiliary structure in the steel truss module (1); Step S2, according to the properties of the module rod (2) to be subjected to locking stress measurement, determine the spatial position arrangement scheme of each sensor in the stress-temperature measurement and acquisition system (4), the stress-temperature measurement and acquisition system (4) comprising a vibrating wire strain gauge, a temperature sensor, a data cable and a collector, the vibrating wire strain gauge and the temperature sensor are both arranged on the module rod (2) to be subjected to locking stress measurement, at least one collector is fixed on each module rod (2) to be subjected to locking stress measurement, the collector is connected to the data cloud platform (3) for communication, and the collected data is uploaded to the data cloud platform (3), and all the vibrating wire strain gauges and temperature sensors arranged on the same module rod (2) as the collector are connected to the collector via data cables; the environmental meteorological monitoring system (5) comprises a meteorological station, the meteorological station is installed in a location with good ventilation and no sunlight shielding near the steel truss module (1), and is used to measure and collect environmental temperature and humidity, sunlight radiation, and the like. radiation and ambient wind speed data, and upload the collected data to a data cloud platform (3); the stress-temperature measurement and collection system (4) has two configuration forms. When the module rod (2) to be subjected to locking stress measurement is the module rod (2) that is subjected to the main stress, the vibrating-wire strain gauge must be arranged at least at two different cross-sectional positions of the module rod (2), and one of the cross-sectional positions is located at the mid-span position of the module rod (2). At least four vibrating-wire strain gauges are arranged at the same cross-sectional position. The vibrating-wire strain gauges at the same cross-sectional position are arranged in a circular array, and the arrangement positions of the vibrating-wire strain gauges at different cross-sectional positions correspond to each other. The temperature sensor must be arranged at least at the mid-span cross section of the module rod (2), and at least four temperature sensors are arranged at the same cross-sectional position. When the module rod (2) to be subjected to locking stress measurement is a module rod (2) of an auxiliary structure, it is only necessary to set a vibrating wire strain gauge and a temperature sensor at the mid-span position of the module rod (2); Step S3, installing the stress-temperature measurement and acquisition system (4) and the environmental meteorological monitoring system (5) when the modular rod (2) is in a loose state at the factory stage, measuring stress-temperature data from a zero stress state, and uploading the data to the data cloud platform (3); Step S4, the stress-temperature measurement and collection system (4) and the environmental meteorological monitoring system (5) are transported synchronously with the module rods (2) or the steel truss modules (1). During the modular construction, the stress-temperature measurement and collection system (4) and the environmental meteorological monitoring system (5) are regularly maintained so that the stress-temperature measurement and collection system (4) and the environmental meteorological monitoring system (5) continuously collect stress and temperature data throughout the entire process and upload them to the data cloud platform (3), so as to completely monitor the entire process of steel structure assembly, loading and transportation, truss box ground assembly, lifting, steel truss module (1) structure formation, steel truss module (1) multi-professional integration, transportation to the site, lifting slide rails, rail drop unloading, and structural gap filling; Step S5, calculate and eliminate the influence of structural temperature stress and the semi-rigid node effect of the truss structure, obtain the locking stress measurement result of the module member (2), based on the plane section assumption, take the average value of the sensor data at four locations as the member axial force, determine the local curvature of the section in the direction according to the sensor stress difference in the corresponding direction of the front and rear two groups of cross-sectional positions, and then determine the magnitude of the bending moment in the direction, so as to separate the axial force and bending moment in the axial force-bending moment coupling effect caused by the semi-rigid node; The temperature field of the module structure under solar radiation is simulated using the measurement data of the meteorological station, and the temperature results are used for verification. The temperature gradient of the module rod (2) is characterized by the measurement results of the temperature sensors at different positions of the rod. The axial force caused by the overall temperature change of the module rod (2) and the bending moment caused by the temperature gradient are eliminated. After eliminating the above two influencing factors, the locking stress monitoring results can be finally obtained.

2. A method for measuring locking stress of a highly modular steel truss structure according to claim 1, characterized in that: The vibrating-wire strain gauge and the temperature sensor on the same module rod (2) share a data collector, the data collector comprising a device power supply module, a signal receiving module, a data calculation module and a communication module, the power supply module is responsible for providing device power support for the data collector, the signal receiving module is connected to the vibrating-wire strain gauge and the temperature sensor via a data cable, and is used to receive a digital signal transmitted by the data cable, the data calculation module calculates the collected digital signal into a monitoring data result, and the communication module is connected to a data cloud platform (3) for communication, and uploads the calculation result of the data calculation module to the data cloud platform (3).

3. A method for measuring locking stress of a highly modular steel truss structure according to claim 1, characterized in that: After the installation of the vibrating-wire strain gauge, temperature sensor and collector, they are protected by a protective shell. The data cable is encapsulated and protected by a protective tube. There are two types of protective tubes for the data cable. PVC tubes are used for protection in straight-line routing positions, and plastic hoses are used for protection in bending areas.

4. A method for measuring locking stress of a highly modular steel truss structure according to claim 1, characterized in that: The vibrating-wire strain gauge and the temperature sensor are fixed to the surface of the module rod (2) in a loose-rod state after the processing is completed. The vibrating-wire strain gauge is fixed by welding or by gluing with casting glue, and the temperature sensor is installed and fixed by gluing.

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