Analysis of jump floor vierendeel space frame

In daily life, if there is a large span of the space frame, the height of the space frame will increase to a certain extent. Therefore, for the large-span structure, the space of the open-web grid layer can be used as a separate building layer. This type of open-web grid is both a structural layer and a building layer. The grid layer has a large span capacity which makes the new structural system have the architectural function of large and small space crossing each other to overcome some architectural limitations of the previous large space standing at the bottom or top of the building, and is especially suitable for large-span, multi-storey and high-rise buildings.

The space frame assembly and implementation of the jump floor vierendeel grid structure is a new space structure system developed from the vierendeel grid structure system. The space frame processing structure system is composed of the vierendeel grid layer and the space frame or space truss supporting the vierendeel grid vertically arranged alternately.

The new spatial structure system is systematically studied from the aspects of its composition, static characteristics and seismic performance. Different structural components make the structure with different mechanical characteristics. Based on the common type of jump floor open web grid structure, we analyzes and studies the internal force distribution and deformation of different types of jump floor open web grid structures such as adding diagonal web members around the grid, unequal spacing of  grids, and space truss as the grid support, under the action of vertical and horizontal loads, and further analyzes the floor slab participation in the work and the application of pre-stress, The change of internal force and deformation of the structure and the conclusion of the processing analysis and calculation of the grid frame provide a theoretical reference for the selection and design of the structure in the engineering design.

In addition, we studies the linear elastic response and the elastic-plastic response of the jump floor vierendeel grid structure under the frequent earthquake and the rare earthquake by using the time-history analysis method. The elastic-plastic response of the structure under the rare earthquake shows that under the conditions of selecting the appropriate section and reinforcement ratio, the structural system processed by the grid frame can meet the design principle of “no collapse in a large earthquake” in the code.

We also supply the analysis results of response spectrum method and time history method are compared in this paper, which can guide the seismic design of this new structural system.

After a detailed study of the mechanical characteristics of the structure under vertical load, we propose a simplified analysis method of the jump floor open-web grid structure based on the flexibility method of the cross beam system considering the shear deformation and the layered method of the multi-story frame under vertical load which greatly improves the simplified method proposed by some scholars in the past. The method has high calculation accuracy and is especially suitable for the preliminary design of the structure. As for the structure of jump floor open web grid, the general concept is that the collapse resistance of the structure system is poor under strong earthquake. Through the analysis of the natural vibration characteristics of different types of jump floor open web grid structures, this paper reveals the influence of the change of grid stiffness and support structure stiffness on the natural vibration frequency and vibration mode of the structure.