Among the safety hazards on construction sites, tower crane accidents accounted for as many as 34% of casualties. The tower crane overturning accident that occurred in a commercial complex project in a capital city last year directly caused three deaths and economic losses of more than 20 million yuan. The post-mortem investigation found that if a tower crane safety monitoring system was installed, this tragedy could be completely avoided. Data show that after the installation of a professional monitoring system, the tower crane accident rate has dropped by 85%, and the efficiency of identifying major hidden dangers has increased by 90%. The latest "Regulations on the Safety Supervision and Management of Construction Lifting Machinery" issued by the Ministry of Housing and Construction clearly requires that all newly started tower cranes must be equipped with a monitoring system that meets the GB/T 5031 standard from 2024. Violators will face shutdown and rectification and a fine of up to 500,000 yuan (link to the original text of the Ministry of Housing and Construction).
This system is like a ”health bracelet” for a tower crane, tracking 8 key parameters in real time: the lifting weight monitoring accuracy is ±1%, the amplitude measurement error is less than 0.5 degrees, the height limit response time is 0.2 seconds, and the wind speed warning range is adjustable from 4-20m/S. More advanced is the three-dimensional monitoring capability-through the hook high-definition camera, the operator can clearly identify the nut-sized connector at an altitude of 50 meters; the dual-axis inclination sensor can perceive the tilt of the tower at 0.1 degrees; the intelligent anti-collision module can simultaneously monitor the trajectory of 3 surrounding equipment. In the super-high-rise project of a central enterprise in Xiong'an New District, the system successfully warned of the 0.3mm settlement deviation of the tower crane foundation, avoiding the potential risk of overturning.
Through the industrial-grade 5G Internet of Things gateway, the system uploads encrypted data packets to the cloud every 3 seconds. The project manager opens the ”Tower Crane Cloud Control” APP on the mobile phone, and can supervise the operation heat map of all tower cranes within 20 kilometers at the same time. When the torque value exceeds 90% of the limit, the platform automatically triggers a three-level response: first, a pulse vibration warning is sent to the operator's cab; if it is not corrected within 5 seconds, an alarm text message is pushed to the safety director; when the critical value is reached, the rotary power supply is remotely cut off. This mechanism successfully prevented overloading and hoisting at a subway construction site in Zhengzhou-at that time, the operator forcibly lifted the overweight steel structure, and the system automatically cut off the power when the load reached 110%, and the crane hovered 10 meters from the ground (smart construction management platform case).
The current mainstream configuration in the market has a total investment of about 28,000-55,000 yuan (including installation), which mainly includes：
Don't panic when you encounter a data transition! The three most common types of faults are dealt with like this：
Data drift: Mostly due to strong magnetic interference, immediately wrap the sensor with a magnetic shield (the magnetic storm causes abnormal data after a heavy rainstorm in a certain project, and it will be restored within 2 hours after shielding)
Video caton: Check the 4G signal strength>-85dBm, or switch to the 5GHz frequency band (a construction site in Guangzhou solves it by adjusting the antenna angle)
False alarm: Repeat the normal operation 3 times under the ”learning mode” set by the system (the false positive rate of the Beijing project has been reduced from 15% to 1%)
Be sure to be equipped with an emergency bypass switch to maintain basic operating capabilities in the event of a failure. Power-off and restart 3 times a month can prevent 80% of software failures.
Look for three certificates and one report: special equipment manufacturing license, explosion-proof certification (EXDCTCT6), measuring instrument type approval certificate, and third-party EMC test report. The three major echelon brands in the market have their own advantages：
The system adopts a ”dual insurance" storage scheme: the local industrial SD card stores detailed data for 90 days (sampling frequency 10Hz), and the cloud server permanently stores key operation records. In the investigation of an accident in Chongqing, it was the black box data three minutes before the capsizing that was retrieved, clearly restoring the whole process of overload-yaw-instability. The smarter system already has the ability to predict-by analyzing the motor current curve for 100,000+ hours, it can warn the reducer failure 300 hours in advance, and the maintenance response time is shortened by 70% (Data report of China Construction Machinery Research Institute).
With the integration of the Internet of Things and BIM technology, a new generation of tower crane safety monitoring system is developing in the direction of digital twins. In the construction of the Hangzhou Asian Games venue, the system maps the operation data of the tower crane to the BIM model in real time to realize the centimeter-level hoisting path planning.
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