Dapeng Town Industrial Park, Tongshan District, Xuzhou City, Jiangsu Province, China
In the installation process of space structures, the aerial bulk method plays an important role in all kinds of construction projects due to its unique adaptability. However, this method requires very high control of the construction process, and many details need extra attention.
1.Pre-construction preparation
(1) Accurate measurement and positioning: before installation, the measurement of the foundation must be accurate. The axis, elevation and positional deviation of the pre-buried parts of the foundation may affect the precision of the net frame installation. It is necessary to use high-precision measuring instruments to carry out comprehensive testing of the foundation to ensure that the indicators meet the design requirements. For example, the elevation deviation of the pre-embedded parts should be controlled within a very small range, otherwise it will lead to poor connection of the net frame rods and affect the overall structural stability.
(2) Material and equipment inspection: the quality of the net frame rods, nodes and auxiliary materials should be strictly checked. The specification, model, length and appearance quality of the rods, node size, processing accuracy, etc., all need to comply with the design and specification standards. At the same time, check the installation of mechanical equipment, such as cranes, welding machines, etc., to ensure that its performance is good, reliable operation, to provide protection for the smooth progress of construction.
2.Rod and node installation
(1) Order and positioning of rods: when bulk installation at high altitude, it is crucial to reasonably arrange the order of installation of rods. Generally from one end of the net frame to the other end, or from the middle to both ends symmetrically. Install the lower chord pole and lower chord node first to form a stable reference plane, and then install the web pole and upper chord pole in turn. During the installation process, use measuring instruments to monitor the position of the bars in real time to ensure their accurate positioning. If the positioning deviation of the rods is too large, the subsequent rods can not be installed smoothly, and even lead to uneven distribution of structural internal force.
(2) Node connection quality: the node is the key part of the net frame structure, and its connection quality directly affects the structural safety. When welding ball nodes, strictly control the welding process parameters to ensure the quality of the weld to avoid defects such as false welding and slag. When installing the bolt ball node, ensure that the bolt tightening degree meets the requirements to prevent loosening. At the same time, carry out the necessary anti-corrosion treatment on the node connection parts to extend the service life of the structure.
3.Precision control during installation
(1) Real-time monitoring and adjustment: real-time monitoring is required during the installation of the net frame. Once the deviation is found to be out of the permissible range, analyse the reasons and take adjustment measures immediately. If the deviation is caused by errors in the production of rods, the rods can be fine-tuned or replaced; if it is due to improper installation sequence, the subsequent installation steps need to be adjusted in time.
(2) Temperature impact response: Temperature changes will cause thermal expansion and contraction of the net frame rods, affecting the installation accuracy. When constructing in high or low temperature environment, the influence of temperature on the length of rods should be considered. Installation can be carried out in the appropriate temperature period, or the length of the rods can be calculated by temperature correction.
4.Safety management
(1) Protection of overhead work: overhead bulk method is mostly overhead work with high safety risk. Construction personnel must be equipped with a full range of personal protective equipment, such as helmets, safety belts, safety shoes, etc., and ensure that they are properly worn and used. At the same time, set up solid safety protection facilities in the operation area, such as safety nets, protective railings, etc., to prevent people from falling and object strikes.
(2) construction equipment safety: lifting equipment, power tools, etc., on the construction site should be regularly checked and maintained to ensure their safe operation. Lifting equipment lifting capacity, lifting height and other parameters to meet the construction requirements, overloading is strictly prohibited. Before the use of power tools, check their insulation properties to prevent electric shock accidents.
5.Quality acceptance
(1) Process acceptance: In the process of net frame installation, stage-by-stage quality acceptance should be carried out. The quality of the installed rods and nodes connection, as well as the overall size and shape of the net frame should be checked, and the quality problems should be found and corrected in time. Such as each completed layer of network frame installation, a comprehensive inspection, qualified and then the next layer of construction.
(2) Completion and acceptance: after the installation is completed, carry out comprehensive completion and acceptance. According to the design documents and relevant norms and standards, the appearance of the net frame quality, geometric dimensions, node connection strength, structural deflection and other testing and evaluation. Only the indicators are in line with the requirements, the net frame can be officially put into use.
