Space truss structure

he space frame structure is a spatial dumpling connecting rod structure, which is a spatial high-order statically indeterminate structure system with good mechanical performance.
advantage:
Space structure, less steel consumption, economical;
Wide application range and strong adaptability;
The overall rigidity is large, the stability is good, the shock resistance is good, and the safety reserve is high
Flexible shape, convenient layout, beautiful and lightweight
Industrial production
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1. Type of Space Frame structure

2. The Three Gorges Project is a magnificent project spanning the century. Its warehouse has a total length of 642.7m and a width of 39.0m. There are two 1200T bridge cranes and two 125T small bridge cranes in the workshop. The roof load is relatively large. The roof adopts a square cone welded ball space frame . The frame structure and the space frame structure are supported on the upstream and downstream wall structures. The space frame structure participates in the overall function of the warehouse structure, and the load combination is very complicated.

3. 一 . The form and selection of space frame 1. The characteristics of the space frame 2. The form of the space frame structure 3. Selection of space frame structure

4. 1. The characteristics of the space frame The space frame structure is a spatial dumpling connecting rod structure, which is a spatial high-order statically indeterminate structure system with good mechanical performance. advantage: Space structure, less steel consumption, economical; Wide application range and strong adaptability; The overall rigidity is large, the stability is good, the shock resistance is good, and the safety reserve is high Flexible shape, convenient layout, beautiful and lightweight Industrial production

5. 2. The form of the space frame structure 1. The space frame structure is divided into double-layer space frame and multi-layer (three-layer) space frame according to the number of layers. 2. The double-layer space frame is composed of the upper mystical layer, the abdominal poles, and the lower mystical layer. 3. The three-layer space frame is composed of upper, middle, lower, upper and lower abdomen layers.

6. Double-layer space frame form 1. Plane quilting system 1 Two-way orthogonal placement 2. Two-way orthogonal oblique placement 3. Two-way oblique intersecting oblique placement 4. Three-way space frame 2. Quadrangular pyramid system 1. Positive quadrangular pyramid system 2. Positive discharge quadrangular pyramid system 3. Unidirectional polyline space frame 4. Oblique quadrangular pyramid system 5. Checkerboard quadrangular pyramid space frame 6. Star quadrangular pyramid 3. Triangular cone system 1. Triangular cone space frame 2. Evacuate triangular cone space frame 3. Honeycomb triangular cone space frame

7. (1), two-way orthogonal positive-laying space frame The two-direction orthogonal right-laying is formed by the vertical crossing of two-direction plane trusses. When applied in a rectangular building plan, the two-way quilting is perpendicular to the boundary (parallel) The number of space frame in the two directions should be arranged in an even number. If it is an odd number, the internodes in the middle of the quilt should be made into cross webs. Because the space frame composed of the upper and lower chords of the space frame is rectangular, the webs are in the plane of the upper and lower chords, which is geometrically variable.

8. The force of the two-way orthogonal orthographic space frame is similar to the two-way equal-rigidity cross beam, which varies with the plane size and supporting conditions. For peripheral support, the closer the plane size is to the square, the closer the internal forces of the quilting rods in the two directions, and the more significant the spatial effect. But with the increase of the side length ratio, the one-way force transmission effect increases obviously. For the point-supported space frame, the internal force of the rod near the support and the rod of the main quilt is larger, and the internal force of the rods in other parts is small, and the difference between the two is large.

9. Two-way Orthogonal Space Frame

10. (2) Two-way orthogonal diagonally placed space frame The two-way orthogonal diagonal space frame is formed by the vertical cross of the two-way flat quilting frame. When applied in the rectangular building plan, the angle between the two-way frame and the boundary is 45 degrees. It can be understood as a two-way orthogonal orthographic space frame that rotates at an angle of 45 degrees when it is placed on the building plane. The span of the two directions of the two-way orthogonal diagonal space frame frame is different, the number of nodes is more or less, and the short bracket near the corner is more rigid, and it supports the long quilt perpendicular to it. Reducing the force on the mid-span chord of the long quilted frame is beneficial to the force on the space frame frame.

11. Two-way orthogonal diagonally placed space frame

12. (3) 、两向斜交斜放网架 两向斜交斜放网架是由两个方向绗架相交 α 角交叉而成 , 形成棱形网格。适用于两个方向网格尺寸不同 , 而要求弦杆长度相等。 这类网架节点构造较复杂 , 受力性能欠佳 , 因此 , 只是在建筑上有特殊要求时才考虑选用

13. Two synchro diagonally placed space frame Three-way space frame

14. (4) Three-way space frame The three-way space frame is composed of three quilting frames intersecting each other at an angle of 60 degrees. The space frames of the upper and lower chord planes of this type of space frame are regular triangles, which are geometrically invariant, with large spatial rigidity, good force performance, and the support force is relatively uniform, but the members that meet at a node can reach as many as 13 The root and node structure is more complicated, and welded hollow sphere nodes should be used. Three-way space frames are suitable for larger spans (greater than 60 meters), and the building planes are triangles, hexagons, polygons and circles. When used for circular planes, some non-triangular space frames will appear around them.

15. (5), forward quadrangular pyramid system Basic unit of quadrangular pyramid system Square pyramid space frame

16. The quadrangular pyramid space frame frame is composed of inverted quadrangular pyramids, the four sides of the cone bottom are the upper chords of the space frame, the cone edges are the webs, and the tops of the cones are connected to form the lower chord. When the building plane is rectangular, the upper and lower chords are parallel (perpendicular) to the boundary. The upper and lower nodes are respectively connected with 8 rods, and the node structure is relatively uniform. If the dimensions of the two directions of the space frame are equal, the angle between the web rod and the lower chord plane is 45 degrees, h=0.7s (h is the height of the space frame, s is the space frame size), and the lengths of the upper and lower chords and the web rod are equal, so that the rod Piece standardization. The space rigidity of the square pyramid space frame frame is larger than that of other types of square pyramid space frame frame and two-way space frame frame, and the amount of steel used may be slightly higher. This kind of space frame is widely used at home and abroad due to standardization of rods and unified nodes, which is convenient for factory production.

17. (6), the quadrangular pyramid space frame is being discharged and evacuated The positive discharge and evacuated quadrangular pyramid space frame is based on the positive quadrangular pyramid space frame, and some of the web and lower chords in the quadrangular pyramid units are appropriately removed, so that the space frame size of the bottom chord is twice as large as the space frame size of the top chord. The number of rods of this kind of space frame is small, the total number of web rods is about 3/4 of the total number of the web rods of the quadrangular pyramid space frame frame, and the lower chord is reduced by about 1/2, so the structure is simple and the economic effect is better. As the surrounding space frames are not suitable for drawing rods, the number of space frames in the two directions should be odd. If h=0.7s, the lengths of the upper and lower chords and webs are equal. The force of this kind of space frame is similar to that of the orthogonal cross beam system, and the stiffness is weaker than that of a quadrangular pyramid.

18. Positively placed quadrangular cone evacuated space frame

19. (7), one-way broken line space frame The one-way broken-line space frame is a space frame made up of a quadrangular pyramid space frame without the vertical upper and lower chords, and a circle of longitudinal upper chords is reserved around it, which is suitable for peripheral support. The quadrangular pyramid space frame is placed in the front, and it is used when the aspect ratio is greater than 3 in the case of peripheral support. The unidirectional broken-line space frame is in a state of unidirectional force, and the force is transmitted by a V-shaped truss. It is more rigid than a simple plane truss, and no support system is required. All members are stressed members. .

20. One-way polyline space frame

21. (8). Place the quadrangular pyramid space frame diagonally The diagonally placed quadrangular pyramid space frame is also composed of inverted quadrangular pyramids. The upper chord space frame is placed orthogonally, and the bottom chord space frame is placed orthogonally; that is, the bottom chord is perpendicular (or parallel) to the boundary, and the top chord is at 45 degrees to the boundary. Angle. The length of the upper chord of this kind of space frame is equal to 0.7 times the length of the lower chord. In the case of peripheral support, the upper chord is compressed and the lower chord is tensioned. The space frame reflects the tension of the long rod and the compression of the short rod, so the force of the rods is reasonable. In addition, there are relatively few members that meet at the nodes (6 upper chord nodes and 8 lower chord nodes). When the height of the space frame is half the length of the lower chord, the upper chord and the diagonal web are the same length. This kind of space frame is suitable for surrounding support, with simple node structure, reasonable force on rods, and less steel consumption. It is also a form that is widely used in domestic engineering.

22. Inclined quadrangular pyramid space frame

23. (9). Checkerboard-shaped quadrangular pyramid space frame The checkerboard-shaped quadrangular pyramid space frame is named because its shape is similar to that of a chess board. On the basis of the quadrangular pyramid, except for the surrounding quadrangular pyramid, the middle quadrangular pyramid is emptied, the lower chord is placed orthogonally, the upper chord is orthogonally placed, and the lower chord is at an angle of 45 degrees with the boundary, and the upper chord is placed at an angle of 45 degrees. The rod is perpendicular (or parallel) to the boundary. It can also be understood as the diagonally placed quadrangular pyramid net frame rotated 45 degrees around the vertical axis. This kind of space frame also has the advantages of short upper chord and lower chord length, and there are few intersecting rods on the nodes, and the roof panel has a single specification, which is suitable for peripheral support.

24. Checkerboard-shaped quadrangular pyramid space frame

25. (10). Star-shaped quadrangular pyramid space frame The star-shaped quadrangular pyramid space frame is made up of two inverted triangular small trusses crossing each other. The bottom side of the two small quilts constitute the upper chord of the space frame, the upper chord is placed orthogonally and diagonally, the vertices of each unit are connected to form the bottom chord, and the bottom chord is placed orthogonally. The upper chords are in the same plane. This kind of space frame also has the characteristics of short upper chord and lower chord length, and the force of the rods is reasonable. When the height of the space frame is equal to the length of the upper chord, the upper chord is the same length as the vertical rod, and the oblique web is the same length as the lower chord. This kind of space frame is suitable for peripheral support.

26. Star-shaped quadrangular pyramid space frame

27. (11). Triangular cone space frame The triangular pyramid system space frame is composed of inverted triangular pyramids. The basic unit is a triangular cone. The triangular pyramid space frame is composed of inverted triangular pyramids. Both the upper and lower chord planes are equilateral triangle meshes. The vertex of the lower chord triangle is on the centroid projection line of the upper mystic triangle mesh. The force of the triangular space frame is uniform. If the height of the space frame is [2/3] ½ times the space frame size, the upper and lower chords and web members of the space frame are of equal length. The number of intersecting rods at the upper and lower chord nodes are both 9, and the node structure types are uniform. Triangular cone space frame is generally suitable for large and medium-span buildings and heavy roof buildings. It is most suitable when the building plan is triangular, hexagonal or circular.

28. Triangular cone space frame

29. (12). Evacuate the triangular cone space frame The evacuated triangular pyramid space frame is based on the triangular pyramid space frame, and some of the webs and lower chords in the triangular cones are appropriately removed, so that the upper chord mesh is still triangles, and the lower chord mesh is a combination of triangles and hexagons or all six. For the combination of polygonal shapes, the rule of taper tapping in the former is: none of the space frames along the periphery of the space frame will taper, and the inside will be separated from the second circle along three directions to extract a triangular cone. There is a hatched part in the figure. To remove the mesh of the cone. The latter starts from the surrounding space frame, and draws one at two intervals along three directions. The hatched part in the figure is the space frame with the cone removed. The evacuated triangular pyramid space frame has many rods removed, and the overall rigidity is not as good as the dipyramidal space frame. It is suitable for small and medium-span triangular, hexagonal and circular building planes.

30. Evacuate the triangular cone space frame

31. (13). Honeycomb space frame The honeycomb triangular pyramid space frame is composed of inverted triangular pyramids arranged according to a certain rule. The upper chord space frame is triangular and hexagonal, and the lower chord space frame is hexagonal. The upper chord of this kind of space frame is shorter, the lower chord is longer, and the force is reasonable. Each node only converges with 6 rods, the node structure is unified, and the amount of steel used is less. The honeycomb triangular pyramid space frame frame itself is geometrically variable. It needs to rely on the horizontal restraint of the support to ensure that its geometry remains unchanged. Attention should be paid to the construction and installation. The analysis shows that the internal forces of the lower chord and web members and the vertical reaction force of the support can be obtained from the static balance condition, and the internal force of the upper chord is determined according to the horizontal restraint of the support. This kind of space frame is suitable for surrounding small and medium span roofs.

32. Honeycomb space frame