How to design steel structure truss reasonably?

1. The influence of the change of truss section size on its internal force

For spatial triangular steel tube truss, the section shape can be determined after the section height, chord width and joint length are determined. With the change of the chord width, the internal force of the chord is basically unchanged, but the deflection of the belly and mid-span is obviously changed.

2. Mechanical characteristics of pipe truss structure

Tube truss is a lattice structure with round rods connected at both ends. The spatial triangular steel tube truss under vertical uniform load shows the mechanical mechanism of shear and chord bending of the belly bar. The section height is the main factor affecting the axial force of the chord.

3. Pipe truss structure calculation

The height of three-dimensional trusses can be 1/12 to 1/16 of the span; The thickness of the arch can be 1/20 ~ 1/30 of the span, and the height of the arch can be 1/3 ~ 1/6 of the span. Chord (main), belly rod (branch) and two belly rod (branch) Angle shall not be less than 30°.

4. Calculation principle

The internal force and displacement of cylindrical truss structure under gravity load and wind load are calculated. In addition, the displacement and internal force under the action of earthquake, temperature change, support settlement, construction and installation load should be calculated according to the specific situation. According to the elastic theory, the finite element method can calculate the internal force and displacement of space bar system.

5. Static calculation

The section design of steel tube truss should be carried out after the calculation of displacement and internal force. If the tube truss section needs to be adjusted, it should be redesigned to meet the design requirements.

6. Seismic calculation

In the case of one-dimensional earthquakes, the effect of multiple earthquakes can be calculated by means of activation decomposition response spectrum.To sum up, this is the design characteristics of steel tube truss structure. In order to ensure the safety and aesthetics of steel tube truss, it is necessary to master the mechanical characteristics of steel tube truss.