Is the space frame more economical than the steel plane truss?
The simple difference is: steel space frame have balls (bolt balls, hollow balls), steel trusses basically do not use balls, and some are useful, such as supports, steel pipes and steel pipes where the connection is not suitable, balls can be used. According to the project, the steel truss is better than the steel mesh frame in terms of stress , and can be used for a span of more than 100 meters; the steel soace frame generally does not exceed a span of 100 meters. When calculating with MST. The plane shape of the space frame is ellipse. The center of the ellipse is the high point. Slopes cannot be circular arcs.
Similar to the slope of a four-sided sloping roof, the upper chord coordinate transformation may be more careful. Of course, the space frame ball nodes at the gutter are not equal to the elevation (two slopes are drained according to the short axis direction):
1. Gradually rise from the short axis end point to the long axis end point along the periphery;
2. But the gutter can still be made of equal height sections;
3. Remember to set the water baffle and the water outlet at a certain distance in the gutter. Otherwise, rainwater is easy to accumulate at the end of the short axis. Cause poor drainage or even overflow.
Of course, the space frame ball nodes at the gutter are not of equal elevation (drainage on the two slopes in the direction of the short axis): In this case, the height of the support of the space frame will be different. It is more troublesome to process and install, and it is better to lay the circle flat. As we all know, space frame is a kind of economical structure suitable for large span because of its bidirectional space force. However, there are many applications of purlins of tube trusses and cold-formed trusses at present. So I wonder that whether the space frame must be more economical than the steel truss?
The space frame is not necessarily more economical than the steel plane truss. I think the reason for not necessarily saving is that the space frame has many structural members and is subjected to a small force. In order to meet the slenderness ratio, a larger member should be used. How to remove some structural rods with little effect is one of the keys to optimizing the amount of steel used in the space frame.
Reduce the amount of space frame structure of steel in addition to pumping rod, I think there is still a key point worth improving, that is, the amount of steel used in the current nodes is very large, reaching about 25%-30%. Therefore, can make some of text on the space frame node design, put forward some more reasonable node connection form, or is a common form of nodes for the current do some improvements, in this way, the amount of steel used in the space frame can be reduced a lot.