What regulations should be complied with when lifting or jacking the space frame structure

 When lifting or jacking the space frame structure, the following requirements should be met:

The construction shall be carried out in accordance with the regulations of the construction organization design.

Steel pipe welders on the construction site shall pass the all-position welding procedure qualification and welder examination of the welded ball joints and steel pipe connections before they can participate in the construction.

The hoisting method should be determined comprehensively according to the stress and structural characteristics of the space frame, under the requirements of quality and schedule, and combined with the local construction technical conditions.

 

The selection of the position and number of lifting points for the hoisting of the grid shall comply with the following requirements:

It should be consistent with the force condition when the space frame structure is in use or the members must meet the force requirements after checking;

The reaction force at the lifting point should be less than the load capacity of the lifting equipment;

The load of each lifting equipment should be close.

After the hoisting method is selected, the reaction force of the hoisting point, the internal force and deflection of the members, the stability of the supporting column and the horizontal thrust of the space frame under wind load should be checked separately during the construction phase of the space frame, and reinforcement measures should be taken if necessary. .

All welds of the welded joint space frame shall be visually inspected and recorded. For the butt welds of the tie rods and balls of the large and medium-span steel pipe space frame, non-destructive inspection shall be conducted, and the number of samples shall not be less than 20% of the total number of welds. The quality standards shall comply with the current national standard "Code for Acceptance of Steel Structure Engineering Construction Quality" 》(GB50205) the requirements for level 2 welds.

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The benefits of steel structure design for the present and the future

 The benefits of steel structure design can be seen from both the present and the future. The advantage of steel structure design for the present is that it can spend less cost to get the maximum value. Because the steel structure design is generally used in social public buildings. The large-scale use of steel structure design is equivalent to saving money for the country, and it is also a way to enhance the country's comprehensive national strength. After all, the money saved is a lot. The money can then be used for other infrastructure construction. Of course, saving money is only one of the many benefits of steel structure design for contemporary times.

The advantage of steel structure design for the future is that it allows future generations to see the crystallization of our wisdom. This is just like the situation where we sincerely sigh after seeing many things left over from history. The younger generations will invent many other new things, but they will still be proud of the design of the steel structure built by their ancestors. No matter how the future develops, the emergence of steel structure design is an advancement in society and productivity. The thoughts and concepts of these steel structure designs are worthy of scrutiny and have been verified by history. Therefore, steel structure design is a real wealth for people in the future.

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Introduction and installation of interval space frame structures

     The interval space frame structure is a new type of space structure system developed form the open-web space frame structure system. The structure system is composed of the open-web space frame layer and the space frame or space truss supporting the open-web space frame vertically arranged alternately. When the span of the space frame structure is large, the height of the space frame is increased accordingly. Therefore, for a large-span structure, the space of the open-web space frame layer can be used as a separate building layer. This kind of open-web space frame in not only a structural layer but also a building layer, but also has a large spanning ability. This make the new structural system have the architectural function of large and small spaces intersecting each other, which overcomes the previous large space standing at the bottom or top of the building. Some architecture limitations are particularly suitable for large span high-rise buildings.

The composition of different structures makes the structure have different stress characteristics. Based on the ordinary interval space frame structure, we analyzed and studied the addition of oblique webs around the grid, the unequal spacing of the grid grid, and the support of the grid as the space. The internal force distribution and deformation of different types of interval space frame structures such as trusses under vertical and horizontal loads. At the same time, the internal force and deformation changes of the structure when the floor is involved in work and prestressing are further analyzed, and the conclusions of the analysis and calculations It provides a theoretical reference for the selection and design of the structure in engineering design.

After studying the force characteristics of the structure under the vertical load in detail, based on the flexibility method of the cross beam system considering the shear deformation and the layering method of the multi-layer frame under the vertical load, interval vierendeel grid structures method is proposed. The simplified analysis method of the open-web grid structure has made a great improvement to the simplified method proposed by some scholars in the past. This method has higher calculation accuracy and is especially suitable for the preliminary design of the structure.

For interval space frame structures, the usual concept is that the structural system has poor collapse resistance under strong earthquakes. Through the analysis of the natural vibration characteristics of different types ofinterval space frame structures, the stiffness of the space frame and the rigidity of the supporting structure are revealed The impact of the change of the structure on the natural frequency and mode shape of the structure. The response spectrum method has studied the seismic performance of the structure under three-dimensional one-dimensional excitation and simultaneous excitation in the three directions of the earthquake. The internal force and deformation of the structure under the action of the earthquake are obtained, and the response spectrum method is used for seismic design. Type interception order. Time history analysis method is used to study the linear elastic response of jump-story grid structure under frequent earthquakes and the elastoplastic response under rare earthquakes. The elasto-plastic response of the structure under rare earthquakes shows that the structural system can meet the design principle of “no collapse in large earthquakes” under the conditions of selecting appropriate cross-sections and reinforcement ratios. The analysis results of the response spectrum method and the time history method are compared, which can guide the seismic design of this new type of structural system.