The document discusses different types of space frame structures. It describes a square cone welded ball space frame being used for the roof of a large warehouse that is part of the Three Gorges Project in China. The space frame structure helps support the large roof load and participates in the overall structure of the warehouse. It then examines various forms of space frame structures including double-layer, multi-layer, planar quilting systems, quadrangular pyramid systems, and triangular cone systems. Each type is defined and its characteristics and suitable applications are outlined.
3. 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.
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10. 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
11. 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
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13. 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.
14. 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
15. (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.
16. 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.
18. (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.
22. (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.
24. 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.
25. (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.
27. (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. .
29. (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
31. (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.
33. (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.
35. (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.
37. (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.
39. (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.