Key Points for Reviewing Documentation of Stationary Tower Cranes

Fixed tower cranes (commonly referred to as tower cranes) are equipment that can easily lead to serious safety accidents—particularly the catastrophic collapse or toppling of a tower crane, which not only risks causing mass casualties but also results in significant financial losses due to the crane's substantial value. The government imposes extremely strict safety regulations on tower cranes, requiring construction commission safety supervision departments to oversee every stage of the process, including qualification checks for installation and dismantling as well as inspection procedures. Additionally, only certified testing organizations are authorized to conduct technical assessments of the cranes, while supervisors are tasked with reviewing and officially signing off on the installation and dismantling processes, thereby assuming full responsibility for safety compliance.

I. Document Review

The tower crane documentation primarily includes a review of the general layout plan, instruction manual, and certificate of conformity.

1. The review of the general layout plan is conducted to verify the rationality of the tower crane’s spatial arrangement. The supervisor should require the construction unit to accurately depict surrounding buildings on the general layout plan, clearly indicating their heights. Additionally, the location of high-voltage lines must be marked with the corresponding voltage values, and the radius of the tower crane’s boom length should be drawn, specifying the safe clearance distance from high-voltage lines. This safety distance must comply with the requirements outlined in the "Safety Technical Code for the Use of Construction Machinery" (JGJ 130-2001). If the required clearance cannot be met, it is advisable to request the power supply department to conduct an inspection and provide a written document, followed by the implementation of specialized vertical and horizontal isolation measures. Furthermore, the tower crane must maintain appropriate safety distances from nearby buildings, and it should also be checked whether sufficient space has been reserved for dismantling operations.

Interference may occur between tower cranes in a group engineering project. Therefore, each crane’s horizontal coordinates, elevation, and independent height should be clearly marked on the general layout plan for easy inspection and adjustment. If adjusting the horizontal position or installation height proves impossible, ground anchors and limiters can be added. In cases of severe interference, the installation unit may be required to implement special measures, such as shortening the crane’s jib and reducing the counterweight accordingly. Additionally, care must be taken to ensure that the tower crane foundations do not intersect with existing utility pipes, trenches, or drainage systems. The foundation elevation should also be set lower than the planned future road surface—or sufficient soil depth must be reserved for landscaping and greenbelt embankments.

2. The instruction manual must match the actual product. Key review points include verifying whether the base drawings align with both the manual and the physical item, checking for any errors or omissions in the base drawings, and ensuring that the foundation’s load-bearing capacity, foundation type, reinforcement details, and concrete grade are all correctly specified. Additionally, confirm that the size, embedment depth, and exposed height of anchor bolts are appropriate, and verify the presence of any lightning protection and grounding systems. If necessary, request submission of the lifting performance chart for reference during load testing.

3. The key focus of the inspection certificate review is the manufacturing date and factory serial number. New tower cranes must undergo load testing, while tower cranes that have been in use for 4 years require a major overhaul. For tower cranes nearing 8 years of service, manufacturers must provide documented proof extending their usage beyond the standard limit. Additionally, verify that the factory serial number matches the actual unit and other relevant documentation.

4. Pre-Signature Inspection: Before signing, ensure that all foundational construction documents—such as excavation inspection records, concealed reinforcement inspection forms, concrete mix designs, pouring permits, concrete placement logs, and inspection request forms—are fully signed, accurately reflect the actual conditions, and comply with the supervision procedures. Pay special attention to verifying whether both parties have properly signed and stamped the tower crane foundation acceptance form during its handover.