Scaffold safety monitoring evaluation method based on complex working conditions

Abstract

The invention relates to a scaffold safety monitoring evaluation method based on complex working conditions, which comprises the following steps of: constructing a simulation model of a scaffold, and analyzing displacement characteristics and strain characteristics of the scaffold under the complex working conditions and a buckling mode of the scaffold under a corresponding load mode based on the simulation model. One or more displacement monitoring point positions suitable for safety monitoring evaluation are selected according to displacement characteristics, displacement sensors capable of detecting displacement of the displacement monitoring point positions in real time are arranged, and one or more strain monitoring point positions suitable for safety monitoring evaluation are selected according to scaffold strain characteristics and buckling modes. And analyzing the inherent frequency and vibration mode of the scaffold based on the simulation model, and analyzing the adaptability of the scaffold on site. According to the invention, the monitoring point position can be selected better and more accurately, the number of required monitoring points is small, the monitoring precision is high, the stress and strain conditions of the structure can be grasped on the whole, and comprehensive monitoring of the scaffold under complex working conditions is realized.

Description

Technical Field

[0001] The invention relates to a safety monitoring and evaluation method or process for a scaffold under complex working conditions. Background Art

[0002] As an indispensable temporary structure in construction projects, the stability and reliability of scaffolding are directly related to the life safety of construction workers and the progress of the project. In the design of scaffolding, the material, size and adaptability of the scaffolding to the construction environment should be carefully evaluated to ensure that the scaffolding can remain stable under various construction conditions. In order to avoid safety accidents in scaffolding, a larger safety factor is usually used to ensure the structural strength. It can also be analyzed through mathematical models to optimize the design of the scaffolding to save costs while ensuring safety. During use, the scaffolding can be monitored manually or with monitoring facilities, and reinforced or rebuilt when certain displacements and deformations occur. For example, Chinese patent document CN118190383A discloses a safety monitoring system for an attached climbing scaffold. A plurality of stress monitors are arranged on the climbing scaffold to observe the influence of the stress concentration on the structure when the climbing scaffold climbs upward; a travel monitor is arranged on the climbing mechanism of the climbing scaffold to monitor whether the travel is normal; wind speed and direction monitors are arranged around the outer sides of the top of the climbing scaffold to monitor whether the climbing is normal during the typhoon season; an inclination monitor is arranged on the frame of the climbing scaffold for inclination monitoring; an audible and visual alarm is arranged at each of the above monitoring points. When the alarm value is reached, the alarm is activated until it is manually closed or the monitoring value is lower than the alarm value. The system is always in a controlled state during the entire construction process, including abnormal overload on the frame. It can be discovered in time, providing timely and reliable monitoring information for management personnel. Although the existing technology can solve the corresponding technical problems in the occasions to which it is adapted, there are still problems such as complex detection process or time lag, especially for complex working conditions, so it is necessary to make further improvements. Summary of the invention

[0003] The purpose of the present invention is to provide a safety monitoring and evaluation method for scaffolding under complex working conditions to facilitate the safety monitoring and evaluation of the scaffolding.

[0004] The technical solution of the present invention is: a safety monitoring and evaluation method for scaffolding under complex working conditions, constructing a simulation model of the scaffolding, analyzing the displacement characteristics (for example, the distribution of displacement contour lines) of the scaffolding under complex working conditions (for example, a combination of various design loads) based on the simulation model, according to the displacement characteristics of the scaffolding (simulation model) under complex working conditions, combined with the on-site conditions of the scaffolding, selecting one or more (usually multiple distributed at different locations) displacement monitoring points suitable for safety monitoring and evaluation, setting a displacement sensor (various devices capable of collecting / obtaining displacement signals / data) capable of real-time detection of the displacement of the displacement monitoring points, and implementing a safety evaluation related to the displacement based on the displacement signal / data obtained by the displacement sensor.

[0005] When the safety assessment conclusion related to displacement is unsafe or dangerous, implement corresponding safety alarms and / or adopt necessary countermeasures.

[0006] Furthermore, the strain characteristics (e.g., strain distribution) of the scaffolding under complex working conditions and the buckling modes under corresponding load modes are analyzed based on the simulation model. According to the strain characteristics of the scaffolding (simulation model) under complex working conditions and the buckling modes under corresponding load modes, combined with the on-site conditions of the scaffolding, one or more (usually multiple distributed at different locations) strain monitoring points suitable for safety monitoring and evaluation are selected, and strain sensors (various devices capable of collecting / obtaining strain signals / data) that can detect the strain at the strain monitoring points in real time are set. Based on the strain signals / data obtained by the strain sensors, safety evaluation related to strain and / or buckling is implemented.

[0007] When the conclusion of the safety assessment related to strain and / or buckling is unsafe or dangerous, implement corresponding safety alarms and / or adopt necessary countermeasures.

[0008] Preferably, the strain sensor is a strain gauge.

[0009] Preferably, the load combination for complex working conditions is set according to the design load.

[0010] One or more complex working conditions can be set according to the load combination method.

[0011] Preferably, the displacement monitoring points suitable for safety monitoring and evaluation are points whose displacement is closely related to safety (for example, the same as or highly related to the safety indicators specified in the specifications) and are easy to monitor (for example, the displacement amplitude is large in the scaffolding).

[0012] Preferably, the strain monitoring point suitable for safety monitoring and evaluation is a point whose strain is closely related to safety (for example, the same or highly correlated with the safety index specified in the specification, or the same or highly correlated with the strain of the buckling part / the first buckling part) and is easy to monitor (for example, the strain amplitude is large in the scaffold). For example, it can be a point that is positively correlated with the strain of the buckling part / the first buckling part and has a larger strain amplitude / is easier to detect (for example, the correlation coefficient is significantly greater than 1).

[0013] Preferably, the setting of monitoring points (including displacement monitoring points and strain detection points) should be adapted to the on-site deployment of the corresponding sensors. In the case where there are multiple points that can be replaced by each other in monitoring, it is preferred to set the points of the sensors more conveniently as monitoring points.

[0014] Preferably, based on reliability considerations, the set monitoring points should have a certain amount of redundancy.

[0015] Furthermore, the natural frequency and vibration mode of the scaffolding (simulation model) are analyzed based on the simulation model, and the adaptability of the scaffolding in the field is analyzed.

[0016] When there are vibration sources on site that can resonate with the scaffolding and thus affect the safety of the scaffolding (for example, mechanical equipment that generates vibration), the natural frequency of the scaffolding can be changed by changing the simulation model (changing the scaffolding design) to avoid resonance with the vibration source. Under appropriate circumstances, the operation time of the scaffolding can also be staggered with the vibration (working) time of the vibration source (if possible).

[0017] Preferably, a simulation model of the scaffold is constructed according to the scaffold design, or a simulation model is constructed according to basic data and design requirements.

[0018] The scaffolding design may be an AutoCAD drawing of the scaffolding.

[0019] The basic data and design requirements may include on-site conditions, erection height, construction location and geological survey reports. Other data may also be included based on actual conditions. All basic data should be reliable.

[0020] Furthermore, the physical properties (physical parameters) of the scaffolding components (materials) and the physical properties of the scaffolding foundation are input into the simulation model as physical properties (parameters) of the simulation model.

[0021] Furthermore, the preliminary constructed simulation model was evaluated for its effectiveness.

[0022] Preferably, the method of implementing the frame effectiveness evaluation on the initially constructed simulation model is: based on the simulation model, the calculation results of the bending and deflection, support reaction, load, wall connection bearing capacity and foundation bearing capacity of the frame (simulation model) are obtained, and whether the physical form of the frame is reasonable and whether each calculation result meets the requirements is analyzed; if the physical form of the frame is unreasonable and / or at least one calculation result does not meet the requirements, the simulation model is adjusted or modified, and the above calculation and analysis judgment are repeated on the adjusted or modified simulation model until the physical form of the corresponding frame is reasonable and the above calculation results meet their respective corresponding requirements, which is to pass the frame effectiveness evaluation, and the simulation model that passes the frame effectiveness evaluation is the constructed simulation model.

[0023] Furthermore, simulation analysis operations are performed based on the simulation model to obtain relevant data for safety evaluation, including reaction force indicators, displacement contours, buckling modes and other relevant data / indicators.

[0024] The beneficial effects of the present invention are: 1) it is able to better and more accurately select monitoring points, requiring fewer measuring points and high monitoring accuracy; 2) it is able to grasp the stress and strain conditions of the structure as a whole; 3) it is economical, with less construction difficulty and a short construction period; 4) it ensures the operational stability and safety of the scaffolding / support system; 5) it is able to realize comprehensive monitoring of the scaffolding under complex working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0026] See also Figure 1 , the data / indicators used for safety evaluation mainly include: 1) Node displacement: Vertical displacement: Monitoring the vertical displacement of each node of the scaffold is key. For example, during construction, if the vertical displacement of the top node of the scaffolding pole exceeds a certain limit, it may indicate that the scaffolding is overloaded or the foundation has uneven settlement. Generally speaking, for ordinary building scaffolding, the vertical displacement of the top of the pole should not exceed the allowable limit (such as 1 / 500 - 1 / 400 of the scaffolding height). If the vertical displacement of a node is found to be close to or exceeds this limit in the finite element analysis of the simulation model, the scaffolding needs to be inspected and reinforced.

[0027] Horizontal displacement: Horizontal displacement data is important for evaluating the stability of scaffolding under wind load or other lateral forces. For example, in coastal areas or high-rise building construction, when the scaffolding is subjected to large wind loads, the horizontal displacement of its side nodes can reflect the scaffolding's ability to resist lateral displacement. If the horizontal displacement is too large, it may cause the scaffolding to become unstable as a whole. Usually, the design specifications specify the horizontal displacement limit of the scaffolding under wind load. By comparing the horizontal displacement results obtained by the finite element analysis of the simulation model with the wind load, potential safety hazards can be discovered in a timely manner.

[0028] 2) Stress data Axial stress of rods: Scaffolding poles are mainly subjected to axial pressure, and crossbars may be subjected to axial tension or pressure. The axial stress data obtained through the finite element analysis of the simulation model can be used to determine whether the rods are overloaded. For example, for scaffolding poles, if the axial compressive stress exceeds the allowable compressive strength of the material (such as the design value of the compressive strength of Q235 steel is about 215N / mm²), the poles may yield and fail. Therefore, real-time monitoring of axial stress and comparison with material strength is an important measure to ensure the safety of scaffolding.

[0029] Bending stress: When the scaffold is subjected to uneven loads (such as uneven stacking of materials on the scaffolding board) or lateral forces (such as wind loads), bending stress will be generated in the rods. Areas with high bending stress are prone to local damage. For example, at the mid-span position of the scaffolding crossbar, if the bending stress exceeds the bending strength of the material, the crossbar may bend or even break. The finite element analysis of the simulation model can accurately locate these high bending stress areas, providing a basis for key monitoring.

[0030] Shear stress: Shear stress will be generated in the rods at the nodes of the scaffold or when subjected to diagonal loads. For example, shear stress is concentrated near the connection nodes between the diagonal rods and the vertical rods and cross rods. If the shear stress exceeds the shear strength of the material, it may cause the node connection to fail. The shear stress results of the finite element analysis of the simulation model can be used to evaluate the safety of the nodes, and focus on these high shear stress areas in actual monitoring.

[0031] 3) Strain data Rod strain: Strain is an indicator of deformation corresponding to stress. The stress situation can be indirectly reflected through strain data, and strain gauges are commonly used sensors in actual monitoring. For example, a strain gauge is attached to the scaffolding pole, and the measured strain is compared with the analysis result based on the strain distribution obtained by finite element analysis. If the measured strain exceeds the expected strain range, it may indicate that the actual stress state of the scaffolding does not match the design or analysis, and further inspection is required to see if there is abnormal load or damage to the structure.

[0032] 4) Modal analysis data Natural frequency and vibration mode: Modal analysis of the scaffolding can obtain its natural frequency and vibration mode. In the actual construction environment, when the frequency of external excitation (such as construction equipment vibration, wind-induced vibration, etc.) is close to the natural frequency of the scaffolding, resonance will occur, causing the scaffolding to vibrate more and even be damaged. For example, if the finite element analysis of the simulation model obtains that the first-order natural frequency of the scaffolding is 5Hz, and the frequency generated by the vibration equipment near the construction site is also around 5Hz, measures need to be taken to avoid resonance, such as adjusting the operating frequency of the equipment or reinforcing the scaffolding to change its natural frequency. The vibration mode data can show the deformation form of the scaffolding under different vibration modes, helping to identify the weak parts of the structure so that the vibration conditions in these areas can be focused on during the monitoring process.

[0033] The implementation and application of the present invention may include a preparation stage, a physical performance analysis stage, a monitoring point arrangement stage, a frame monitoring data analysis stage, an abnormal monitoring data safety performance evaluation stage and a frame post-processing stage.

[0034] 1) Preparation stage: including simulation model establishment and physical performance input.

[0035] Establishment of simulation model: The scaffolding simulation model should be designed and established based on reliable data such as on-site working conditions, erection height, construction location, and geological survey reports; Physical property input: Input physical properties based on the scaffolding component materials used in the design and the foundation used for the on-site scaffolding.

[0036] 2) Physical performance analysis phase: including safety performance evaluation and frame effectiveness evaluation.

[0037] Safety performance evaluation: including reaction force index, displacement contour, various data index records, buckling mode and other data. The above technical data are obtained after computer simulation analysis; Frame effectiveness evaluation: refers to verifying whether the physical form of the calculation results is reasonable, whether the bending and deflection calculation results meet the requirements of the specifications, whether the support reaction calculation results meet the requirements of the specifications, whether the load calculation results meet the requirements of the specifications, whether the wall connection bearing capacity calculation results meet the requirements of the specifications, and whether the foundation bearing capacity calculation results meet the requirements of the specifications; if the calculation results do not meet the requirements of the specifications, adjust and modify the model, recalculate, and repeat the above process; if the calculation results meet the requirements of the specifications, the frame effectiveness evaluation is carried out through computer simulation calculation.

[0038] 3) Monitoring point layout stage: After obtaining the simulation model calculation data, the monitoring points are arranged in combination with the feedback data and actual on-site conditions.

[0039] 4) During the frame monitoring data analysis phase, monitoring data is collected in real time to analyze the frame's horizontal and vertical displacements, areas with large stress distribution, and the most dangerous strain data.

[0040] 5) Safety performance evaluation of abnormal monitoring data. After completing the data analysis, timely feedback on abnormal data is provided to demonstrate and verify the current framework and evaluate whether it still meets the usage and safety requirements.

[0041] 6) Frame post-processing stage: Reinforce or dismantle the frame based on the safety performance evaluation results of abnormal monitoring data.

[0042] During the construction / use process, real-time monitoring is carried out based on the monitoring data of the monitoring points / corresponding sensors. When the monitoring data (displacement, strain, etc.) exceeds the limit, timely response measures are taken (for example, alarm, evacuation, scaffolding reinforcement, etc.).

[0043] In the event of monitoring data exceeding the limit, analyze the reasons for the monitoring data exceeding the limit. If improper use causes the load range to be exceeded or other dangerous situations occur, correct it and strengthen management; if there is no improper use (for example, load exceeding the limit, excessive load concentration, etc.), adjust the design, reconstruct the scaffolding simulation model (including safety evaluation), and implement safety evaluation (including safety evaluation related to displacement, and safety evaluation related to strain and / or buckling) on ​​the reconstructed scaffolding simulation model. The actual working condition (load condition, which may include dynamic and static loads according to actual conditions) when the monitoring data exceeds the limit will appear, and when a certain safety factor is added, it will be used as one of the working conditions (complex working conditions) for safety evaluation (increase the safety evaluation under this working condition).

[0044] Aiming at the defects and shortcomings of the existing technical regulations for safety monitoring of special-shaped scaffolding under complex working conditions, the present invention selects monitoring points of scaffolding under complex working conditions and conducts monitoring and evaluation processes. A scaffolding physical performance model system is constructed through computer simulation technology to simulate the real state of the scaffolding under complex working conditions to obtain scaffolding monitoring points. The scaffolding under complex working conditions can be accurately monitored in real time and non-destructively.

[0045] Unless otherwise specified or when one preferred or optional technical means is a further limitation of another technical means, the preferred and optional technical means disclosed in the present invention can be arbitrarily combined to form several different specific implementation methods.

Claims

1. A safety monitoring and evaluation method for scaffolding under complex working conditions, characterized in that Construct a simulation model of the scaffolding, analyze the displacement characteristics of the scaffolding under complex working conditions based on the simulation model, select one or more displacement monitoring points suitable for safety monitoring and evaluation based on the displacement characteristics of the scaffolding under complex working conditions and the on-site conditions of the scaffolding, set up displacement sensors that can detect the displacement of the displacement monitoring points in real time, and implement displacement-related safety evaluation based on the displacement signal / data obtained by the displacement sensor.

2. The safety monitoring and evaluation method for scaffolding under complex working conditions according to claim 1 is characterized in that The strain characteristics of the scaffolding under complex working conditions and the buckling modes under corresponding load modes are analyzed based on the simulation model. According to the strain characteristics of the scaffolding under complex working conditions and the buckling modes under corresponding load modes, combined with the on-site conditions of the scaffolding, one or more strain monitoring points suitable for safety monitoring and evaluation are selected, and strain sensors that can detect the strain at the strain monitoring points in real time are set. Based on the strain signals / data obtained by the strain sensors, safety evaluation related to strain and / or buckling is implemented.

3. The safety monitoring and evaluation method for scaffolding under complex working conditions according to claim 2 is characterized in that The strain sensor is a strain gauge.

4. The safety monitoring and evaluation method for scaffolding under complex working conditions according to claim 1 is characterized in that The natural frequency and vibration mode of the scaffolding are analyzed based on the simulation model, and the adaptability of the scaffolding in the site is analyzed.

5. The safety monitoring and evaluation method for scaffolding under complex working conditions according to claim 4 is characterized in that When there is a vibration source on site that can resonate with the scaffolding and thus affect the safety of the scaffolding, the natural frequency of the scaffolding is changed by changing the simulation model to avoid resonance with the vibration source.

6. The safety monitoring and evaluation method for scaffolding under complex working conditions according to any one of claims 1 to 5, characterized in that A simulation model of the scaffolding is constructed according to the scaffolding design, or a simulation model is constructed according to basic data and design requirements.

7. The safety monitoring and evaluation method for scaffolding under complex working conditions according to claim 6 is characterized in that The basic data and design requirements may include on-site conditions, erection height, construction location and geological survey report.

8. The safety monitoring and evaluation method for scaffolding under complex working conditions according to claim 7 is characterized in that The physical properties of the scaffolding components and the physical properties of the scaffolding foundation are used as physical property inputs of the simulation model and input into the simulation model.

9. The safety monitoring and evaluation method for scaffolding under complex working conditions according to any one of claims 1 to 8, characterized in that Conduct framework effectiveness evaluation on the preliminarily constructed simulation model.

10. The safety monitoring and evaluation method for scaffolding under complex working conditions according to claim 9 is characterized in that The method of implementing the frame effectiveness evaluation on the initially constructed simulation model is: based on the simulation model, the calculation results of the frame's bending and deflection, support reaction, load, wall connection bearing capacity and foundation bearing capacity are obtained, and whether the physical form of the frame is reasonable and whether the calculation results meet the requirements are analyzed; if the physical form of the frame is unreasonable and / or at least one calculation result does not meet the requirements, the simulation model is adjusted or modified, and the above calculation and analysis judgment are repeated on the adjusted or modified simulation model until the physical form of the corresponding frame is reasonable and the above calculation results meet their respective corresponding requirements, which is to pass the frame effectiveness evaluation, and the simulation model that passes the frame effectiveness evaluation is the constructed simulation model.

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