How to define the structural system of the upper part of the bottom steel frame
Here, it is necessary to supplement the longitudinal steel beams that are arranged in the frame, as well as the necessary components, which have not been arranged. Finally, the floor and the load. Floor and roof panels can be set according to the actual needs of the elastic plate or rigid plate. Generally speaking, we do not consider the role of the floor on the steel beam, it is recommended not to consider the stiffness outside the surface, you can choose the rigid plate or elastic membrane. If you want to consider the role of the floor on the steel beam, the use of steel and concrete composite beam will be better. The roof plate is usually made of colored profiled steel plate, when the structure is calculated without considering the stiffness of the plate. Therefore, the thickness of the 0 plate can be used to guide the load, while the component will not provide additional stiffness. But this is a problem, the top stiffness is much smaller relative to the lower frame, vibration modes and translational or reverse calculation results will be relatively worse, individuals that can be set to a smaller slab thickness, such as 10 thick, limited considering roof panels in the plane
Modeling method: it is recommended to use the "portal frame three-dimensional design" model, the model established in the face of each frame, the lower frame can be set up directly by the grid or mezzanine. After the completion of the building will be built into the tie rod (vertical frame beam can be tied to the input), the longitudinal beam is not built. Roof horizontal support, inter column support can be modeled in this.
(PS: regarding the specification and selection of structure types, characteristics and structure as well as the earthquake was not simply that, according to the above statement set must be correct, need further discussion.)Framework modeling: frame "to 3D model and load model, input directory is still just entered, can see the program automatically generates each standard layer on top of the roof also automatically set the" node on high". This is why I suggest to use the portal frame modeling, which can skew and variable cross-section beam generating top-level conveniently.
Design method: after the completion of three-dimensional modeling, loading and calculation, according to the design results to adjust the cross-section to the appropriate cross-section. Each elevation should be designed until all the facades are completed. The parameter is set inside, the design specification should choose "steel structure" specification, structure type can choose "structure of gabled frames" (if only the local sandwich it) or "multi-layer steel structure workshop" (if there are many layers of it). The roof beam is suggested to be checked by the door gauge and the bending member is checked.
