Title
Configuration
Geometrical characteristic
Stiffness characteristic
Force characteristic
construction
Two - way orthogonal space frames
It consists of the intersection of two plane trusses parallel to the direction of the building boundary. The intersection angle of the trusses in each direction is 90 degrees, that is, the upper and lower chords are placed positively
The lengths of the upper and lower chords are equal, and the upper and lower chords and the webs are located in the same vertical plane, and there is a common vertical rod at the intersection of the plane trusses in each direction
The basic unit is geometrically variable. In order to increase its spatial rigidity and effectively transmit horizontal loads, additional inclined rods should be set along the upper (lower) chord plane of the support perimeter of the
It is greatly affected by the plane size and support conditions. The peripheral support is close to a square plane, the force is uniform, and the internal force of the rod is not very different. With the increase of the side length ratio, the one-way force characteristic is obvious
There are few types of rods, which can be assembled into a plane truss first, and then assembled together, which is more conducive to construction
Two orthogonal diagonal space frame
It consists of the intersection of two plane trusses parallel to the direction of the building boundary. The intersection angle of the trusses in each direction is 90 degrees, that is, the upper and lower chords are placed in the positive direction. Just turn it 45 degrees when it is placed on the building plane, that is, the upper and lower chords are inclined
The lengths of the upper and lower chords are equal, and the upper and lower chords and the webs are located in the same vertical plane, and there is a common vertical rod at the intersection of the plane trusses in each direction
Since the is of the same height, the rigidity of the truss at the corner ends is relatively large, and it has a certain elastic support for the long truss perpendicular to it, thereby reducing the bending moment in the middle of the truss, and the stiffness is higher than that of the two-way orthogonal .
When the plane is rectangular, the force is relatively uniform, and the supports at the four corners of the frame generate upward pulling force; in order to reduce the pulling force, it can be designed without corner columns
There are few types of rods, which can be assembled into a plane truss first, and then assembled together, which is more conducive to construction
Three-way space
It is composed of the intersection of plane trusses in three directions, and the intersection angle is 60 degrees, that is, the upper and lower chords have positive and oblique placement.
The lengths of the upper and lower chords are equal, and the upper and lower chords and the webs are located in the same vertical plane. There is a common vertical at the intersection of the plane trusses in each direction. The is generally an equilateral triangle
The basic unit is geometrically unchanged, and the span, number of internodes and stiffness of the truss in each direction are different, and the spatial stiffness of the entire is greater than that of the two-directional . Suitable for large-span projects
All rods are force-bearing rods, which can evenly transmit the force to the support system, and have good force-bearing performance.
Complex node structure (up to one node meeting 13 members); when used for circular planes, there are irregular s around
One-way folded broken line (folded plate )
It is formed by a series of plane trusses obliquely intersecting each other into a V shape, that is, the upper and lower chords are placed in the positive direction, and it can also be regarded as a positive quadrangular pyramid without the upper and lower chords.
The lengths of the upper and lower chords are equal, and the upper and lower chords and the webs are located in the same vertical plane, and there is a common vertical rod at the intersection of the plane trusses in each direction
The rigidity is higher than that of a simple plane truss, and there is no need to arrange a support system. In order to strengthen its spatial rigidity, some upper chord members should be added around it.
Only the upper and lower chords in the span direction are in a one-way force status
Fewer pipe types
Checkerboard quadrangular pyramid
It is formed by turning the inclined quadrangular pyramid (see below) at an angle of 45 degrees, that is, the upper chord is placed upright, and the lower chord is placed obliquely.
The upper chord is orthogonally placed, the lower chord is orthogonally placed obliquely, and the projections of the centroids of the upper and lower chords are coincident
The space rigidity is smaller than that of the quadrangular pyramid . When the periphery is arranged as a full cone, the rigidity is better.
This kind of frame has short upper chords under compression and long lower chords under tension, which can give full play to the function of the cross-section of the rods, and the force is reasonable.
There are few connecting rods at the nodes, 6 at the upper chord node and 8 at the lower chord node, and the node structure is simple
Diagonal square pyramid
The unit is composed of inverted quadrangular pyramids, but connected by the corners of the bottom sides of the inverted quadrangular pyramids, that is, the upper chord is placed obliquely, and the lower chord is placed upright.
The upper chord is orthogonally slanted, while the lower chord is parallel to the boundary
The space rigidity is smaller than that of the square pyramid
This kind of frame has short upper chords under compression and long lower chords under tension, which can give full play to the function of the cross-section of the rods, and the force is reasonable.
There are few nodes members, 6 at the upper chord node and 8 at the lower chord node, and the structure is simple
Honeycomb triangular cone
Connect the bottom angle of the inverted triangular pyramid to the corner to form the upper chord of the , and connect the top of the cone with a rod to form the lower chord of the .
The upper chord plane is a regular arrangement of triangles and hexagons, the lower chord is a single hexagon, and the oblique web and the lower chord are located in the same plane
The space rigidity is smaller than that of the square pyramid
This kind of frame has short upper chords under compression and long lower chords under tension, which can give full play to the function of the cross-section of the rods, and the force is reasonable.
In the common form of , the number of members and nodes is small. However, the triangular and hexagonal mesh of the upper chord plane increases the specification of the roof panel