Construction Control Technology of Long Span Space Steel Structure

In recent years, with the deepening and increasing development of reform and opening up, steel structure has become a new building systems which are being used more and more widely. Long span steel structures are mainly used in public buildings, such as theaters, great halls, concert halls, exhibition halls, stadiums, airports, etc. Large span steel structures can also be used in industrial buildings, such as the general assembly workshop of an aircraft manufacturing plant. The large span steel structures mainly work under self-weight loads. The main contradiction is to reduce the weight of the structure itself, so it is most suitable to use large span steel structures. 

1.Characteristics of Construction Activities of Long Span Space Steel Structure

1)Structural styles are increasingly rich

The current space steel structure building is more complex and advanced than the traditional single frame building structure. The Bird’s Nest is a typical representative building. It is built with a complex space truss structure. In order to meet the needs of large scale comprehensive buildings, the actual span of the space steel structure far exceeds the requirements that traditional building forms can meet. It is primarily constructed from high-strength steel components.

2) Wide application of modern prestressing technology

Prestressing technology plays a very important role in stabilizing long span building structures, and at the same time has very important significance for the overall shape of the tension and the cable dome. So far the world’s largest two-way tension beam steel building structure is the National Stadium, and prestressing technology has played a significant role in its construction. In addition, most of the steel structure buildings also cooperate with other ecological imitation technologies in order to achieve good appearance characteristics, and adopt various styles of node design methods.

2.Construction and installation technology of long span steel structure

At present, there are many methods for the construction of long span steel structures, and each method has its own different characteristics and adaptable steel structures. During installation, it is necessary to comprehensively assess the structural system of the steel structure, construction conditions and daily methods used on the urban surface, which can be summarized into four categories: high-altitude bulk installation, strip installation, overall installation, and sliding installation. Each method is different. The characteristics are introduced as follows:

1)High-altitude bulk There are two main types of high-altitude bulk: the full bracket method and the cantilever method. It is mainly to install the parts or small components directly on the design position. The full bracket method is mainly to install parts, while the cantilever method is mainly small puzzle pieces. Since the installation components are mainly spliced and installed at high altitudes, a large amount of support materials and equipment are required during the construction process. Large scale cantilevered space steel structures are generally installed by high-altitude splicing. A few points should be paid attention to during the construction process of high-altitude bulk: the appropriate assembly sequence should be determined according to the different building structures of the steel structure, and the cumulative error of the building components should be minimized during the assembly process ; in order to ensure the building quality of the steel structure Test and adjust the built structure ; the cantilever method must ensure the stability and rigidity of the unit due to the installation of small units at high altitudes; due to the construction hiding at high altitudes, the safety of the main construction personnel and construction operations must be guaranteed question.

2)Strip (block) installation

Strip installation refers to dividing the steel structure into strips or blocks, hoisting it to a high-altitude position by lifting equipment, and then installing it as a whole. In order to ensure the quality of the project, the strip or block elements are first installed or welded on the ground.. This installation method requires that the components must meet a certain rigidity to ensure that their own geometric dimensions remain unchanged. The following points should be paid attention to during the construction process of the strip-shaped installation : when hoisting, the hoisting elements should be combined with the lifting capacity of the lifting equipment. When hoisting strip-shaped elements, the force state is approximately a plane structure. Installation accuracy error requires a reasonable arrangement of the location and quantity of lifting equipment, and generally adopts the assembly method for size control. When increasing the height of the supporting tire frame to ensure the arching of the steel structure, it is necessary to pay attention to the influence of the wrong side of the interface position on the butt joint of the structure.

3)Overall lift (jack lift)

The overall construction installation method is first to install the steel structure on the ground, and then use the lifting equipment to lift the steel structure to the construction position. There are mainly three methods: overall lifting, overall lifting, and overall hoisting. The main difference between the overall lifting and the overall lifting is that the position of the lifting equipment is different. When the steel structure is lifted as a whole, the lifting equipment is above the construction position of the steel structure, while the overall lifting is to use a jack to lift the steel structure to the bottom of the steel structure.. The overall installation of steel structures reduces high-altitude operations, reduces the construction safety risks of construction personnel, and also reduces construction costs, which can save construction time and greatly improve construction efficiency. When using the overall construction, the following points should be paid attention to: the placement error of the steel structure construction position during construction should not be too large; the deformation and position change of the overall frame of the steel structure; the difference in the lifting points and the interaction of the forces during the construction process; The number and location of points.

4)Sliding installation

Sliding installation is an installation method that slides the striped steel structure units to the setting position through the pre-set slide rails. Generally, it is carried out through overhead work and can be constructed in parallel with other steel structures in three dimensions. This installation The method can also greatly shorten the construction period and improve the construction efficiency. At the same time, this construction method does not need to use a large number of lifting equipment, and also reduces the cost of steel structure construction.

3.Matters needing attention in the construction control of long span steel structures

Our research on the construction mechanics of long span steel structures still needs continuous exploration; most of the theories are only limited to the experimental stage, and have not really matured in application, so it is difficult to have a breakthrough guiding role in construction. The research is limited to the following aspects: the design, construction and construction integration of long span steel structures I have experienced is relatively low, although there are many design theories of long span steel structures that have been widely used in long span steel structures at home and abroad. However, the advantages of some related design software are only reflected in the design of steel structures, and there is still a lack of necessary theoretical support for construction. Secondly, the current theory of construction mechanics cannot be used for theoretical analysis of the construction of steel structures. Most of the construction of large span steel structures is still limited to experience, lacking scientific verification of construction mechanics, construction risk prediction and risk control. Poor ability and above should be the trend of steel structure construction technology development and research in the future.