Steel structure high-altitude bulk installation

At present, the high-altitude loose assembly method is one of the most commonly used construction and installation methods for space steel structures. According to the loose assembly components, it is mainly divided into the high-altitude bulk flow installation method and the high-altitude block flow installation method. The installation process of the high-altitude component flow installation method is: flow installation from bottom to top, and the stability of the hoisted structure must be ensured. The main advantages of the high-altitude component flow installation method:

(1) The installation has a wide range of applications;

(2) The lifting of the component does not require large lifting equipment, and the requirements for lifting equipment are low;

(3) The installation cost is low.

Of course, the piece-by-piece hoisting of parts also has obvious disadvantages:

(1) a large amount of high-altitude operations;

(2) a long construction period.

The high-altitude block-flowing installation method is the most commonly used construction and installation method for towering structures. This method mainly uses hoisting machinery to lift and install each installation block (or segment or section) block by block, and has strict requirements on the bearing capacity and stability of the incomplete structure of the lower part. The main advantages of the high-altitude block-flow installation method:

(1) The amount of high-altitude work during the construction process is small;

(2) The construction and installation quality is easy to control;

(3) The construction and installation period is short.

Main disadvantages:

(1) The lifting capacity of the lifting equipment is relatively large during installation, and the equipment cost is relatively high;

(2) The transportation cost of the hoisting block is high;

The high-altitude loose assembly method is based on the design drawings, and the structural rods and nodes are directly assembled into a whole at the design position. According to the different units of the scattered assembly, it can be divided into two types: the full-house scaffolding method and the cantilever method. The full-house scaffolding method is mainly It is used for the hoisting of individual parts, such as the hoisting and splicing of a single beam or column. The cantilever method is mainly used for the hoisting of scattered small units. For example, the cantilever end of the truss structure is often installed by the cantilever method. These two methods all need to set up a large number of scaffolding supports, which have low requirements for lifting equipment, but high requirements for the construction site. In general, the high-altitude loose assembly method is suitable for the hoisting construction of various types of space frames, reticulated shells or trusses. Generally, the positioning of each member is precisely controlled through the design coordinates of the nodes. Therefore, during the entire assembly process, the key Coordinate control of nodes is particularly important.

Space steel structure can be divided into flexible space steel structure system and rigid space steel structure system, both of which can be constructed by high-altitude loose-fitting method. The heavy steel structure system is usually constructed in the way of “segmented hoisting and high-altitude splicing”, while the construction of the light steel structure system is generally assembled into hoisting blocks of reasonable size for hoisting construction. At present, the development trend of space steel structure is flexible space steel structure system. The key points of high-altitude scattered construction of flexible space steel structure are as follows:

(1) choose a reasonable high-altitude scattered construction sequence to reduce the accumulation of installation errors;

(2) adopt the cantilever method for construction, The cantilever structure can gradually expand inward or outward;

(3) The position of the support point on the temporary support structure is generally set at the node of the lower chord of the space frame;

(4) In the process of removing the support, it is necessary to prevent individual support points from being concentrated , the temporary support is unloaded proportionally by partition and stage by stage to ensure the safety of the main structure. In the process of unbracing, it is necessary to prevent the instability of the steel structure, and strengthen the most prone to instability to ensure the safety of unbracing. The steel structure of the main building of Ziyang Museum belongs to the category of rigid space steel structure. Most of the steel frame columns weigh more than ten tons, which increases the difficulty of high-altitude bulk construction.