Abstract:
A floating latticework is suitable for a latticework, a truss-frame structure and a net-shell structure over water. The floating latticework is the combination of a latticework ( 1 ) and a floating structure ( 2 ), or members of the latticework ( 1 ) in themselves are able to float. The floating structure ( 2 ) makes the latticework ( 1 ) floated over water, the surface of upper chords of which is in form of a platy structure or covered and fixed with a platy structure, as a plane used for loading. There is an advantage that the space-structure floating body is less influenced by wind and wave, which go through its space. A ship structure and a cofferdam structure are parallel solutions with the above solution. Their skeletons are net-shell structure, wherein they are provided with high structural strength.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a spatial lattice structure, and more particularly to a grid structure, a lattice truss structure, and a reticulated shell structure for use above water. 
         [0003]    2. Related Art 
         [0004]    It is well known that spatial lattice structures include grid structures, lattice truss structures, and reticulated shell structures, which have been widely applied to various places such as gas stations, stadiums, large plants, and warehouses to serve as roof surfaces. The grid structures, lattice truss structures, and reticulated shell structures are assembled by special rod members and joints manufactured in factories through mass production and supported by a plurality of upright posts made of concrete or steel structures fixed on the ground. A grid structure, lattice truss structure, or reticulated shell structure is fixedly connected to supporting posts at some joints of a lower chord, which can form a large building structure by covering flashing boards on an upper chord surface thereof. The spatial lattice structure has advantages of a high structural rigidity, applicable to a long-span space, a light weight, a short construction term, a low cost, and a high degree of industrialization. However, the current spatial lattice structures with the spaces provided there-below being utilized can only be applied on the ground, instead of being applied over water. 
       SUMMARY OF THE INVENTION 
       [0005]    Accordingly, the present invention is directed to a floating latticework, which is used as a floating supporting structure above water. 
         [0006]    In order to achieve the above objective, the present invention provides a variety of floating latticework as follows. 
         [0007]    1. A floating latticework is provided, which is formed by a lattice structure and at least one floating structure. Both the lattice structure and the floating structure share the same importance. The lattice structure and the floating structure may be combined together in two manners. In one manner, the lattice structure is disposed on and fixedly connected to one or more uniformly-distributed floating structures, and alternatively, members of the lattice structure are respectively combined with and fixedly connected to a plurality of floating structures. In the other manner, if the lattice structure is designed in a suspending state, all the members constituting the lattice structure are respectively combined with and fixedly connected to the floating structures, and if the lattice structure is designed in a floating or semi-submerged state, the members of the lattice structure that are submerged or semi-submerged in water are respectively combined with and fixedly connected to the floating structures. The above two combination manners aim at utilizing the buoyant forces of the floating structures to enable the lattice structure to float above water as in the former manner or to enable the lattice structure to maintain the floating, semi-submerged, or suspending state in water as in the latter manner. The combination means that the members of the lattice structure contact with and lean against the floating structures. 
         [0008]    2. The lattice structure combined with the floating structures is a grid structure or a lattice truss structure. 
         [0009]    3. When it is selected that the lattice structure is a grid structure or a lattice truss structure disposed on and fixedly connected to a floating structure, the floating structure is a a          -shaped floating structure. The term          -shaped” refers to a physical configuration of the floating structure as a          shaped hollowed lattice structure. Lower chord joints of the grid structure or the lattice truss structure correspond to joints of the          shaped floating structure. Joints of a          -shape configuration refer to crossing points where the lattices are crossed with each other. 
         [0010]    4. A skeleton of the          -shaped floating structure is a hollowed grid structure or a hollowed lattice truss structure. 
         [0011]    5. When it is selected that the lattice structure is a grid structure or a lattice truss structure disposed on and fixedly connected to a plurality of floating structures, the floating structures are distributed at positions of lower chord joints of the grid structure or the lattice truss structure. 
         [0012]    6. The above floating structures are columnar floating structures with axes thereof perpendicular to a horizontal plane. 
         [0013]    7. The columnar floating structures are provided with a plurality of beckets at bottoms thereof and the beckets are respectively tied with ropes, so as to connect to lower chord members of the lattice structure in an inclined manner, and thus, the bottoms of the columnar floating structures underwater are positioned to be perpendicular to the horizontal plane and do not swing along with waves. 
         [0014]    8. When it is selected that the lattice structure is a grid structure or a lattice truss structure, the floating latticework includes a plurality of floating structures, and members of the lattice structure are respectively combined with and fixedly connected to the floating structures, at least one kind of members selected from a group consisting of web members, lower chord rods, and lower chord joints of the grid structure or the lattice truss structure is combined with and fixedly connected to the floating structures. 
         [0015]    9. The combining process is implemented by a wrapping motion. The floating structures wrap around at least one kind of members selected from a group consisting of the web members, the lower chord rods, and the lower chord joints of the grid structure or the lattice truss structure, so as to enable the members and the lattice structure assembled thereby to have a buoyant force, so that the lattice structure further becomes a floating structure. 
         [0016]    10. When it is selected that at least one kind of rod members selected from the web members and the lower chord rods of the grid structure or the lattice truss structure is combined with the floating structures, the floating structures are hollow columnar floating members with a cross sections at hollow portions thereof the same as that of the selected rod members. The hollow columnar floating members are sleeved on the at least one kind of rod members selected from the web members and the lower chord rods before assembling the members of the lattice structure. 
         [0017]    11. When it is selected that at least one kind of rod members selected from the web members and the lower chord rods of the grid structure or the lattice truss structure is combined with the floating structures, each of the floating structures is a hollow columnar floating structure formed by combining two half shells together. When the two half shells are combined together, a cross-sectional shape at a hollow portion of the hollow columnar floating structure is the same as that of the selected rod members. During assembly, each two half shells are separated first and then jointly wrap around at least one rod member selected from the web member and the lower chord rod. The two half shells are connected in a hinged manner or bound together by a strip. 
         [0018]    12. In the floating latticework according to claim  1 , the lattice structure may be a reticulated shell structure. 
         [0019]    13. The reticulated shell structure is a domed reticulated shell structure disposed on and fixedly connected to a flat-plate-shaped floating structure or an annular floating structure. 
         [0020]    14. Another floating latticework is provided, which includes a grid structure or a lattice truss structure formed by rod members and joint members. An upper chord surface, a lower chord surface, and four side faces of the grid structure or the lattice truss structure are covered with and fixedly connected to plate-shaped steel structures. The plate-shaped steel structures covering the lower chord surface and the four side faces are seal-welded. A space formed by the plate-shaped steel structures for enclosing the grid structure or the lattice truss structure is watertight, that is, the whole structure covered by plates is watertight. In this manner, a watertight floating spatial grid structure or a watertight floating spatial lattice truss structure is formed. 
         [0021]    15. Each of the plate-shaped steel structures may be a relatively small grid structure or lattice truss structure with one chord surface thereof covered with and fixedly connected to a steel plate, or may be a relatively small grid structure or lattice truss structure with a steel plate serving as one chord surface thereof. The term “relatively small” means that a lattice specification of the grid structure or the lattice truss structure constituting the plate-shaped steel structure is smaller or much smaller than that of the grid structure or the lattice truss structure covered by the plate-shaped steel structure. 
         [0022]    16. Another floating latticework is provided, which includes a lattice structure assembled by members. Some or all of the members of the lattice structure are floating members in such a specification that a ratio of a sum of a self weight and a maximum load capacity of the lattice structure to a total volume of the members is smaller than 9800 N/m 3 . The lattice structure partially assembled by or completely assembled by the floating members is a floating latticework, which can submerge, float, or suspend in water. 
         [0023]    17. The floating latticework assembled by the floating members is a floating grid structure or a floating lattice truss structure. 
         [0024]    18. At least one kind of members selected from a group consisting of web members, lower chord joints, and lower chord rods of the floating grid structure or the floating lattice truss structure is floating members. 
         [0025]    19. When it is selected that the lower chord joints of the floating grid structure or the floating lattice truss structure are floating members and provided with devices for connecting to rod members, the lower chord joints are variants and are floating members protruding underwater from the floating grid structure or the floating lattice truss structure assembled thereby. The configuration of variants aims at increasing the volume of the lower chord joints and thus increasing the buoyant force. 
         [0026]    20. When it is selected that, in the floating grid structure or the floating lattice truss structure, the web members are all arranged in an inclined manner and the lower chord joints are floating members, the lower chord joints are provided with devices for connecting to rod members, and the lower chord joints are variants, which may be floating members with upper portions thereof in a vertical columnar shape and lower portions thereof protruding underwater from the grid structure or the lattice truss structure assembled thereby. 
         [0027]    21. When it is selected that the floating grid structure or the floating lattice truss structure includes web members perpendicular to a horizontal plane, and both the lower chord joints and the web members perpendicular to the horizontal plane are floating members, the lower chord joints and the web members are connected integrally and assembled into floating members protruding underwater from the floating grid structure or the floating lattice truss structure assembled thereby. 
         [0028]    22. In the floating latticework according to any one of claims  18 - 21 , the floating members are provided with devices for connecting to joints or rod members. Main bodies of the floating members are watertight hollow shell structures. As for floating rod members, main bodies thereof are watertight hollow columnar structures; as for floating joints, main bodies thereof are watertight hollow spherical structures; and as for floating variants, main bodies thereof are variant hollow structures. Shell walls of such three kinds of watertight hollow shell structures are steel plates, rigidly-covered double-layer reticulated shell structures, or reinforcing bar grid structures filled with foamed plastics therein and coated with cement grouts externally. 
         [0029]    23. When it is selected that at least one kind of rod members selected from the web members and the lower chord rods of the floating grid structure or the floating lattice truss structure is floating members and provided with devices at two ends thereof for connecting to joints, main bodies of the floating members are three-dimensional truss structures with foamed plastic floaters filled therein. 
         [0030]    24. A lower chord surface of the floating grid structure or the floating lattice truss structure is a flat-plate-shaped floating structure or a          shaped floating structure. 
         [0031]    25. The lower chord joints of the floating grid structure or the floating lattice truss structure are fixedly connected to floating structures, so as to increase the buoyant forces. 
         [0032]    26. A floating latticework is provided, which includes a grid structure or a lattice truss structure. The grid structure or the lattice truss structure is filled with foamed plastics therein. 
         [0033]    27. In the floating latticework according to any one of claims  2 - 11 ,  17 - 21 , and  23 - 26 , an upper chord surface of any one of the grid structure, the floating grid structure, the lattice truss structure, and the floating lattice truss structure is a plate-shaped structure. 
         [0034]    28. The plate-shaped structure is a plate-shaped grid structure or a plate-shaped lattice truss structure with a small lattice specification. That is, small plate-shaped grid structures or plate-shaped lattice truss structures are used as an upper chord surface of a large floating grid structure or floating lattice truss structure. 
         [0035]    29. In the floating latticework according to any one of claims  2 - 11 ,  17 - 21 , and  23 - 26 , the grid structure, the floating grid structure, the lattice truss structure, and the floating lattice truss structure are respectively a hollowed grid structure, a hollowed floating grid structure, a hollowed lattice truss structure, and a hollowed floating lattice truss structure. 
         [0036]    30. Another floating latticework is provided, which mainly includes a frame structure. The frame structure is a floating frame structure in such a specification that a ratio of a sum of a self weight and a maximum load capacity thereof to a volume thereof is smaller than 9800 N/m 3 . 
         [0037]    31. Upright posts and crossbeams of the floating frame structure are formed by three-dimensional truss structures externally covered with and welded to steel plate structures, so that the upright posts and the crossbeams covered with and welded to steel plates are watertight when being submerged or semi-submerged in water. Alternatively, the three-dimensional truss structures are filled with foamed plastic floaters therein. 
         [0038]    32. A floating latticework is provided, which includes a plurality of columnar floating structures. End faces and side faces of the columnar floating structures are fixedly connected to each other, so as to form a          shaped floating structure or a floating frame structure. 
         [0039]    33. A use of the floating latticework according to any one of claims  2 - 11 ,  14 - 15 ,  17 - 21 ,  23 - 26 , and  30 - 32  is provided. If an upper chord surface or an upper plane of the floating latticework is a plate-shaped structure, the upper chord surface or the upper plane is used as a supporting surface, and otherwise, the upper chord surface or the upper plane is covered with and fixedly connected to a plate-shaped structure to serve as a supporting surface. The floating latticework is adapted to serve as a supporting structure for offshore floating projects such as water transportation, offshore buildings, offshore plants, offshore floating platforms, offshore drilling platforms, offshore airports, floating wharfs, artificial islands, and floating cities. 
         [0040]    34. A use of the floating latticework according to any one of claims  2 - 11 ,  14 - 15 ,  17 - 21 ,  23 - 26 , and  30 - 32  is provided. If an upper chord surface or an upper plane of the floating latticework is a plate-shaped structure, the upper chord surface or the upper plane is used as a supporting surface, and otherwise, the upper chord surface or the upper plane is covered with and fixedly connected to a plate-shaped structure to serve as a supporting surface. Upright post support structures are fixedly connected on the supporting surface. Vertical planes formed by a plurality of upright posts to serve as wall surfaces are covered with and fixedly connected to plate-shaped structures to serve as wall bodies. The upright post support structures are covered with and fixedly connected to a grid structure, a lattice truss structure, or a reticulated shell structure there-above. The grid structure, the lattice truss structure, or the reticulated shell structure is covered with and fixedly connected to a plate-shaped structure, so as to form a living space above water. 
         [0041]    35. A use of the floating latticework according to any one of claims  2 - 11 ,  17 - 21 , and  23 - 26  is provided, in which the floating latticework is adapted to serve as a supporting structure for a floating bridge. An upper chord surface of the floating latticework is covered with and fixedly connected to a bridge deck. A plane axis of the floating latticework is consistent with that of the bridge deck. The floating latticework is provided with positioning ropes connected to underwater bollards or caissons at two axial sides thereof, so as to form a floating bridge. 
         [0042]    36. In the use of the floating latticework according to claim  35 , the floating latticework is used as a supporting structure for a floating bridge, and a planar shape of the floating latticework is          shaped or          -shaped. 
         [0043]    37. A use of the floating latticework according to claim  1  is provided, in which the lattice structure is a double-layer or multi-layer arched cylindrical-surface reticulated shell structure, and the floating latticework is adapted to serve as a supporting structure for a floating bridge. Two ends of the arched cylindrical-surface reticulated shell structure are respectively fixed to two floating structures. An upper chord surface of the arched cylindrical-surface reticulated shell structure is covered with and fixedly connected to a bridge deck, thereby forming a floating bridge or a portion of a long-span floating bridge for ships to pass below an arched portion thereof. 
         [0044]    38. A use of the floating latticework according to claim  16  is provided, in which the lattice structure is a double-layer or multi-layer columnar reticulated shell structure that floats above water with an axis thereof being horizontal, and the floating latticework is adapted to serve as a supporting structure for a floating bridge. The columnar reticulated shell structure itself is a floating structure. An upper chord surface of the columnar reticulated shell structure is disposed with and fixedly connected to a bridge deck. The columnar reticulated shell structure is provided with positioning ropes connected to underwater bollards or caissons at two axial sides thereof. The two axial sides of the columnar reticulated shell structure are fixedly connected to balance wings for preventing the reticulated shell structure from swinging left and right along with waves, so as to form a floating bridge. 
         [0045]    39. A use of the floating latticework according to claim  14  or  15  is provided, in which the floating latticework is adapted to serve as a box-shaped or flat-plate-shaped floating structure, or as a main body structure of a liquid cargo ship. 
         [0046]    40. A floating reticulated shell structure is provided, which includes a single-layer, double-layer, or multi-layer spherical, box-shaped, columnar, or heterotypic hollow reticulated shell formed by rod members and joints. Peripheral members of the reticulated shell are covered with and fixedly connected to plate-shaped structures to form a rigidly-covered single-layer, double-layer, or multi-layer reticulated shell structure. A space enclosed by the rigidly-covered reticulated shell structure is watertight. The reticulated shell structure is applied above water to serve as a watertight and rigidly-covered spherical floating reticulated shell structure, box-shaped floating reticulated shell structure, columnar floating reticulated shell structure, or heterotypic hollow floating reticulated shell structure. 
         [0047]    41. In the floating reticulated shell structure according to claim  40 , the reticulated shell is a watertight and rigidly-covered columnar double-layer or multi-layer reticulated shell structure with an axis thereof parallel to a horizontal plane, and two axial sides of the watertight and rigidly-covered columnar double-layer or multi-layer reticulated shell structure are fixedly connected to balance wings for preventing the reticulated shell structure from swinging left and right along with waves. 
         [0048]    42. A floating reticulated shell structure is provided, which includes a single-layer, double-layer, or multi-layer reticulated shell formed by rod members and joints. Peripheral members of the reticulated shell are covered with and fixedly connected to plate-shaped structures to form a rigidly-covered single-layer, double-layer, or multi-layer reticulated shell structure. The reticulated shell structure is a ship-shaped reticulated shell structure. The rigidly-covered reticulated shell structure is watertight. The reticulated shell structure is applied above water to serve as a watertight and rigidly-covered ship-shaped floating reticulated shell structure. 
         [0049]    43. A ship body structure is provided, which includes side and bottom skeletons. The side and bottom skeletons are double-layer or multi-layer reticulated shell structures. 
         [0050]    44. A ship body structure is provided, which includes side and bottom skeletons, bulkhead skeletons, and deck skeletons. The side and bottom skeletons are double-layer or multi-layer reticulated shell structures. Both the bulkhead skeletons and the deck skeletons are grid structures or lattice truss structures, or only the bulkhead skeletons are a grid structure or a lattice truss structure. 
         [0051]    45. A floating reticulated shell structure is provided, which includes a spherical, columnar, ship-shaped, double-layer, or multi-layer reticulated shell structure. The reticulated shell structure is filled with foamed plastics in a space between internal and external members thereof. 
         [0052]    46. A cofferdam structure is provided, which includes skeleton structures covered with steel plates in a watertight manner. An axis of the cofferdam structure is perpendicular to a horizontal plane. A horizontal cross section of the cofferdam structure is a circular, elliptic, rectangular, or square-shaped closed line. The cofferdam structure is optionally provided with horizontal pressure support structures therein. The skeleton structures are formed by a columnar reticulated shell structure with an axis thereof perpendicular to the horizontal plane. 
         [0053]    47. Another cofferdam structure is provided, which includes skeleton structures covered with steel plates in a watertight manner. An axis of the cofferdam structure is perpendicular to a horizontal plane. A horizontal cross section of the cofferdam structure is rectangular or square-shaped. The cofferdam structure is optionally provided with horizontal pressure support structures therein. The skeleton structures at four sides of the cofferdam structure are formed by a grid structure or a lattice truss structure with a chord surface thereof perpendicular to the horizontal plane. 
         [0054]    48. A cofferdam structure is provided, which includes skeleton structures covered with steel plates in a watertight manner. An axis of the cofferdam structure is perpendicular to a horizontal plane. A horizontal cross section of the cofferdam structure is rectangular or square-shaped in the middle and semicircular-shaped at two ends thereof. The cofferdam structure is optionally provided with horizontal pressure support structures perpendicular to and supporting two straight-edge surfaces. The skeleton structures at the two straight-edge surfaces of the cofferdam structure are grid structures or lattice truss structures with chord surfaces thereof perpendicular to the horizontal plane. Semicircular cylindrical-surface skeleton structures at two ends of the cofferdam structure are semicircular cylindrical-shaped double-layer or multi-layer reticulated shell structures. The number of layers of each reticulated shell structure corresponds to that of the grid structure or the lattice truss structure. When the grid structure or the lattice truss structure is a double-layer structure, the number of layers of the reticulated shell structure is three. Other cases can be deduced similarly. 
         [0055]    49. A method for manufacturing and mounting the cofferdam structure according to claims  46 - 48  is provided. The method includes the following steps: mounting skeletons of a cofferdam structure on a platform; covering steel plates around the skeletons; optionally providing horizontal pressure support structures in the cofferdam structure; excavating earth from a ground surface underwater in a water area under construction, such that the ground surface underwater is recessed; sinking and mounting the cofferdam structure in position; inserting the steel plates at a periphery of a bottom end of the cofferdam structure deep into the ground surface underwater; filling an underwater concrete or other sealing materials outside the cofferdam structure at the ground surface underwater; and withdrawing water from the cofferdam structure. A cofferdam space enclosed by the steel plates is watertight. The platform is located in the water area under construction and is a floating platform positioned in the water area under construction by positioning ropes. The platform is provided with a hollowed structure at a center thereof and a horizontal surface of the hollowed structure is similar to and slightly larger than a horizontal cross section of the cofferdam structure. A temporary platform is built at the hollowed structure, and the skeletons of the cofferdam structure are assembled on the temporary platform by prefabricated members. The skeletons of the cofferdam structure are columnar reticulated shell structures with axes thereof perpendicular to a horizontal plane. As for a large or very large cofferdam structure with a rectangular or square-shaped cross section, skeletons at four sides thereof are formed by a grid structure or a lattice truss structure with a chord surface thereof perpendicular to the horizontal plane. As for a cofferdam structure with a horizontal cross section being rectangular or square-shaped in the middle and semicircular-shaped at two ends thereof, skeletons at two straight-edge surfaces of the cofferdam structure are formed by grid structures or lattice truss structures with chord surfaces thereof perpendicular to the horizontal plane, semicircular cylindrical-surface skeletons at two ends of the cofferdam structure are formed by semicircular cylindrical-surface double-layer or multi-layer reticulated shell structures, and the number of layers of each reticulated shell structure corresponds to that of the grid structure or the lattice truss structure. If the horizontal pressure support structures are required, the horizontal pressure support structures are grid structures or lattice truss structures with chord surfaces thereof perpendicular to the horizontal plane. In the step of covering steel plates around the skeletons, an assembling process is carried out from the periphery of the bottom end of the cofferdam structure and gradually proceeds upward along side faces of the cofferdam structure. As the mounting height increases, a plurality of ropes is fastened to the bottom end of the cofferdam structure and the other ends of the ropes are fastened to the platform. The temporary platform is dismantled, such that the cofferdam structure falls into the hollowed structure at the center of the platform. By adopting a step-by-step sinking manner, the cofferdam structure is sunk to a height convenient for a person to perform the assembling process while standing on the floating platform. When the cofferdam structure reaches a predetermined height, the cofferdam structure is sunk and mounted in position. 
         [0056]    50. A method for manufacturing and mounting the cofferdam structure according to claims  46 - 48  is provided. The method includes the following steps: mounting skeletons of a cofferdam structure on a platform; covering steel plates around the skeletons; optionally providing horizontal pressure support structures in the cofferdam structure; excavating earth from a ground surface underwater in a water area under construction, such that the ground surface underwater is recessed; sinking and mounting the cofferdam structure in position; inserting the steel plates at a periphery of a bottom end of the cofferdam structure deep into the ground surface underwater; filling an underwater concrete or other sealing materials outside the cofferdam structure at the ground surface underwater; and withdrawing water from the cofferdam structure. A cofferdam space enclosed by the steel plates is watertight. The platform is located in the water area under construction and is formed by a central platform and a peripheral platform surrounding the central platform. Both the central platform and the peripheral platform are floating platforms. The platform is positioned in the water area under construction by positioning ropes. A horizontal surface of the central platform is similar to and slightly larger than a horizontal cross section of the cofferdam structure. The central platform is movably connected to the peripheral platform such that the central platform and the peripheral platform are capable of moving up and down relative to each other. Before an assembling process, the central platform is slightly higher than the peripheral platform or is coplanar with the peripheral platform. A buoyant force of the floating central platform is adjusted by filling water therein. The skeletons of the cofferdam structure are assembled on the central platform by prefabricated members. The skeletons of the cofferdam structure are columnar reticulated shell structures with axes thereof perpendicular to a horizontal plane. As for a large or very large cofferdam structure with a rectangular or square-shaped cross section, skeletons at four sides thereof are formed by a grid structure or lattice truss structure with a chord surface thereof perpendicular to the horizontal plane. As for a cofferdam structure with a horizontal cross section being rectangular or square-shaped in the middle and semicircular-shaped at two ends thereof, skeletons at two straight-edge surfaces of the cofferdam structure are formed by grid structures or lattice truss structures with chord surfaces thereof perpendicular to the horizontal plane, semicircular cylindrical-surface skeletons at two ends of the cofferdam structure are formed by semicircular cylindrical-surface double-layer or multi-layer reticulated shell structures, and the number of layers of each reticulated shell structure corresponds to that of the grid structure or the lattice truss structure. If the horizontal pressure support structures are required, the horizontal pressure support structures are grid structures or lattice truss structures with chord surfaces thereof perpendicular to the horizontal plane. The assembling process is carried out from a bottom of the cofferdam structure and gradually proceeds upwards along side faces of the cofferdam structure, and prefabricated steel plates for covering reticulated shells are mounted at the bottom and side faces of the cofferdam structure, and a cofferdam space enclosed by the mounted steel plates is watertight. When the cofferdam structure is assembled to such a height that the cofferdam structure is capable of floating above water alone, the floating central platform is sunk by filling water therein, then separated from the bottom of the cofferdam structure, and then removed. As the assembling process of the cofferdam structure continues and the height of the cofferdam structure increases, by means of filling water into the cofferdam structure, the cofferdam structure is sunk to a height convenient for a person to perform the assembling process while standing on the peripheral platform. When the cofferdam structure reaches a predetermined height, the cofferdam structure is filled up with water and thus sunk and mounted in position. A sealing material is filled outside the cofferdam structure at the ground surface underwater. Structures in the bottom of the cofferdam structure are removed after the water is withdrawn from the cofferdam structure. 
         [0057]    51. A covering plate used in the floating reticulated shell structure, ship body structure, or cofferdam structure according to claims  40 - 44  and  46 - 48 , is provided, which is adapted to cover and be fixedly connected to a peripheral member of a reticulated shell, or adapted to cover and be fixedly connected to a          -shaped lattice structure that is formed by rod members and joints and is fixedly connected to the peripheral member of the reticulated shell with joints thereof corresponding to joints of the reticulated shell. A length and a width of the covering plate are equal to or integral multiples of that of a lattice. The covering plate is flat-plate-shaped or arched curve-shaped. The covering plate is fixedly connected to the peripheral member of the reticulated shell or the          -shaped lattice structure by seal-welding, or is fixedly connected to the peripheral member of the reticulated shell or the          shaped lattice structure by bolts and then a sealing ring is additionally disposed between the covering plate and the peripheral member of the reticulated shell or the          -shaped lattice structure. 
         [0058]    The beneficial effects of the present invention lie in that, through being combined with the floating structure, the lattice structure is capable of being applied above water, and thus has a wider application range. With the same material consumption, a grid structure, a reticulated shell structure, and a lattice truss structure can cover a relatively large water surface and counteract the influence on the floating structure caused by waves, since they are spatial structures and have advantages of a long span, light weight, and high degree of industrialization. In addition, since the grid structure, the reticulated shell structure, and the lattice truss structure have a sufficient rigidity, a floating latticework serving as the floating structure can effectively overcome the torsional moment effect on the floating structure caused by the waves. When the grid structure or the lattice truss structure is disposed on a plurality of floating structures, or members of the grid structure or the lattice truss structure are respectively combined with floating structures, or the members themselves are floating structures, since the grid structure or the lattice truss structure are spatial structures, various winds and waves pass through the space thereof, which greatly reduces the influence caused by the waves. In addition, since a plurality of floating structures is distributed at lower chord joints, or floating members constituting the lattice structure are uniformly-distributed to form a plurality of “small water surface profiles” on the water surface and they are uniformly-distributed at wave peaks and valleys below a large covering surface, the increase and decrease of buoyant forces at different positions of the floating structures caused by fluctuation of the waves are counteracted naturally. Therefore, the floating grid structure or lattice truss structure is a fairly stable structure. 
         [0059]    As compared with the prior art, the present invention exploits a new use of the grid structure, reticulated shell structure, or lattice truss structure. Instead of utilizing a space covered below the structure, the present invention aims at enabling the structure to float above water to form a novel floating structure, in which the structure of the present invention has a spatial structure, a stable buoyant force, a desirable rigidity, and is easily assembled to form a very large structure, and when a plate-shaped structure is covered on an upper plane of the structure, the structure of the present invention is used to support objects. 
         [0060]    Due to the characteristics of the lattice structure itself, in the present invention, the lattice structure is combined with the floating structure, and members of the lattice structure are floating structures, which belong to a breakthrough from the conventional thinking habits. In the conventional thinking habits, the design philosophy of modern floating structures comes from conventional ship structures. Particularly, a ship structure is a single integral watertight hollow structure, which contacts the water surface in the form of a single closed curve. Such a structure has been used for a long time. What&#39;s more, all structural designs of floating structures including very large floating structures (VLFSs) adopt such a conventional single integral structure with a single “water surface profile”. For example, an offshore floating airport built for the United States by Japan is assembled by six box-shaped floaters, in which each box-shaped floater is 60 m long, 30 m wide, and 3 m high. A “water surface profile” of the offshore floating airport is still a single closed curve. When a wavelength of a wave is larger than a major axis or a minor axis of the “water surface profile”, the floating structures swing along with the wave, which is a problem of the floating structure that has not been solved for such a long time due to the influence of the conventional ship structures. 
         [0061]    As a single integral watertight hollow structure, a ship structure further has another fatal defect. Once the integral watertight hollow structure is damaged, the ship sinks due to water leakage. In contrast, since a floating latticework is a spatial structure, there is no water leakage problem when it floats above water. Especially when a grid structure or a lattice truss structure is supported by many uniformly-distributed light-weight solid floaters made of, for example, foamed plastics, or when the grid structure or the lattice truss structure itself is a floating structure, the floating latticework does not sink as long as it is not overloaded. 
         [0062]    The floating latticework of the present invention is a floating spatial structure, which is a breakthrough from the prior art that a ship is a single integral watertight hollow structure. Due to the characteristics of the lattice structure, the floating latticework has many advantages as described above when serving as a floating structure. These advantages just can meet the requirements of building VLFSs such as offshore buildings, offshore plants, offshore floating platforms, offshore drilling platforms, floating bridges, offshore airports, artificial islands, and floating cities. 
         [0063]    With the same material consumption, the hollowed grid structure or lattice truss structure enables the floating latticework to cover a relative large water surface. 
         [0064]    The floating latticework and floating reticulated shell structure make full use of the sufficient rigidity of the lattice structure. A grid structure or a lattice truss structure is used as skeletons of a box-shaped, flat-plate-shaped, or flat-plate-shaped VLFS, or a liquid cargo ship. A reticulated shell structure is used as skeletons of a ship body structure and a cofferdam structure to achieve a high rigidity and strength. Especially for very large ships and vary large cofferdam structures, the sufficient rigidity of the reticulated shell structure can be sufficiently utilized, thus enabling the very large ships to overcome the torsional moment effect on the ship body caused by the waves and enabling the very large cofferdam structure to overcome the huge water pressure underwater. 
         [0065]    Since the lattice structure is an assembly structure with a high industrialization degree, when using the floating latticework as a floating structure and using a double-layer reticulated shell structure as a ship body structure, it can improve the industrialization degree of floating structures and ships and further accelerate the shipbuilding process. Moreover, the difficulty for manufacturing very large ships can be reduced, thereby making the manufacturing of VLFSs become much easier. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0066]    The present invention will become more fully understood from the detailed descriptions given herein below for illustration only, and thus are not limitative of the present invention. 
           [0067]    The floating latticework is mainly characterized by a combination of a lattice structure and a floating structure and can be easily understood by those of ordinary skills about the lattice technology and floating technology, so that most of the implementations of the present invention are described through words and only a portion of the implementations are illustrated with reference to the drawings. In the drawings, the devices for connecting rod members to joints of the lattice structure and for fixedly connecting the lattice structure to the floating structure are well known to those skilled in the lattice technology and floating technology, and thus are merely described through words, and the details thereof are omitted. 
           [0068]      FIG. 1  is an elevation view and a top view of a grid structure disposed on and combined with a plurality of uniformly-distributed floating structures; 
           [0069]      FIG. 2  is a schematic view of a domed reticulated shell structure disposed on and combined with a floating structure formed by a grid structure; 
           [0070]      FIG. 3  is a schematic view of rod members of a lattice structure combined with and fixedly connected to floating structures; 
           [0071]      FIG. 4  is a schematic view of a rod member of a lattice structure wrapped by a coiled foamed plastic; 
           [0072]      FIG. 5  is a schematic view of a lower chord joint of a grid structure wrapped by a foamed plastic; 
           [0073]      FIG. 6  is a schematic view of rod members and joints of a lattice structure respectively combined with and fixedly connected to floating structures; 
           [0074]      FIG. 7  is a three-dimensional view of a          shaped floating structure and a partial schematic view of a skeleton structure thereof; 
           [0075]      FIG. 8  is a schematic view of a connecting piece for fixedly connecting a cylindrical foamed plastic floater to joints of a grid structure or a lattice truss structure; 
           [0076]      FIG. 9  is a cross-sectional view of a hollow columnar floating member disposed with a watertight steel plate structure and sleeved on a rod member of a lattice structure; 
           [0077]      FIG. 10  is a cross-sectional view of a hollow columnar floating member formed by foamed plastics and sleeved on a rod member of a lattice structure; 
           [0078]      FIG. 11  is a schematic three-dimensional view of two half shells of a hollow columnar floating member for jointly wrapping a rod member of a lattice structure; 
           [0079]      FIG. 12  is a schematic assembled view of a domed reticulated shell structure disposed on and combined with an annular floating structure; 
           [0080]      FIG. 13  is a schematic three-dimensional view of a flat-plate-shaped floating structure formed by covering and seal-welding steel plates on outer surfaces of a grid structure or a lattice truss structure; 
           [0081]      FIG. 14  is a schematic view of a floating grid structure; 
           [0082]      FIG. 15  is a schematic view of a floating cylindrical-surface reticulated shell structure; 
           [0083]      FIG. 16  is a schematic cross-sectional view of a floating cylindrical structure; 
           [0084]      FIG. 17  is a schematic view of a floating grid structure or a floating lattice truss structure, in which lower chord joints are floating members; 
           [0085]      FIG. 18  is a schematic view of a floating grid structure or a floating lattice truss structure, in which web members are all arranged in an inclined manner and lower chord joints are floating members; 
           [0086]      FIG. 19  is a schematic view of a floating grid structure or a floating lattice truss structure, in which vertical web members and lower chord joints are floating members; 
           [0087]      FIG. 20  is a schematic view and a cross-sectional view of a floating grid structure or a floating lattice truss structure, in which main bodies of rod members are three-dimensional truss structures with foamed plastic floaters filled therein; 
           [0088]      FIG. 21  is a schematic view of a floating grid structure or a floating lattice truss structure, in which lower chord joints are fixedly connected to floating structures; 
           [0089]      FIG. 22  is a schematic view of a grid structure or a lattice truss structure with foamed plastics filled therein; 
           [0090]      FIG. 23  is a three-dimensional view of a floating frame structure and a partial schematic view of a skeleton thereof formed by a truss structure; 
           [0091]      FIG. 24  is a schematic plan view of a          -shaped floating structure formed by fixedly connecting end faces and side faces of a plurality of columnar floating structures to each other; 
           [0092]      FIG. 25  is a schematic view of a living space above water formed by using a floating grid structure as a supporting structure and covering a grid structure thereon; 
           [0093]      FIG. 26  is a cross-sectional view of a floating bridge using a floating grid structure as a supporting structure thereof; 
           [0094]      FIG. 27  is a top view of a floating bridge using a floating grid structure as a supporting structure thereof; 
           [0095]      FIG. 28  is a top view of a floating bridge using a          -shaped floating grid structure as a supporting structure thereof; 
           [0096]      FIG. 29  is a top view of a floating bridge using a          -shaped floating grid structure as a supporting structure thereof; 
           [0097]      FIG. 30  is a schematic view of a floating bridge using a double-layer arched cylindrical-surface reticulated shell structure disposed on and combined with floating structures to serve as a supporting structure thereof; 
           [0098]      FIG. 31  is a cross-sectional view and a top view of a floating bridge using a double-layer columnar floating reticulated shell structure as a supporting structure thereof; 
           [0099]      FIG. 32  is a schematic three-dimensional view of a ship-shaped reticulated shell structure or ship-body skeletons formed by a reticulated shell structure; 
           [0100]      FIG. 33  is a schematic view of a spherical reticulated shell structure with foamed plastics filled in a space between internal and external members thereof; 
           [0101]      FIG. 34  is a schematic view of a columnar reticulated shell structure with foamed plastics filled in a space between internal and external members thereof; 
           [0102]      FIG. 35  is a schematic view of a ship-shaped reticulated shell structure with foamed plastics filled in a space between internal and external members thereof; 
           [0103]      FIG. 36  is a schematic three-dimensional view of a cofferdam structure with a circular-shaped cross section and with skeletons formed by a reticulated shell structure; 
           [0104]      FIG. 37  is a schematic three-dimensional view of a cofferdam structure with an elliptical-shaped cross section and with skeletons formed by a reticulated shell structure; 
           [0105]      FIG. 38  is a plan view of a cofferdam structure with a rectangular-shaped cross section and with skeletons at four sides thereof formed by grid structures; and 
           [0106]      FIG. 39  is a schematic view of a cofferdam structure with a cross section being rectangular in the middle and semicircular-shaped at two ends thereof, in which skeletons at two long sides thereof are formed by grid structures, and skeletons at two ends thereof are formed by reticulated shell structures. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0107]    1. A floating latticework is provided, which is formed by a lattice structure and at least one floating structure. The lattice structure includes a grid structure, a lattice truss structure, and a reticulated shell structure. The grid structure includes various grid structures, such as an ortho-laid quadrangular pyramid grid, a three-way grid, a hollowed triangular pyramid grid, a thickening grid, a single-layer grid, and a double-layer grid. The lattice truss structure is not a common three-dimensional truss structure, but a special and regular lattice truss structure among the three-dimensional truss structures, and includes various lattice truss structures, such as a thickening lattice truss structure, a double-layer lattice truss structure, and a hollowed lattice truss structure. The reticulated shell structure includes, for example, a three-way cylindrical-surface double-layer reticulated shell, a cylindrical or square-columnar double-layer reticulated shell, and a rigidly-covered arched and domed reticulated shell. The floating structure mainly functions to provide a buoyant force, and it may be of a variety of types, as long as it can provide a sufficient buoyant force, such as a buoyant box, a floating drum, a ball float, a foamed plastic floater wrapped with glass fiber reinforced plastics (GFRP) (it should be noted that: any foamed plastic floater mentioned below is externally wrapped with the GFRP). The lattice structure aims at providing a structure, and the floating structure aims at providing a buoyant force. Any forms of the grid structure, the lattice truss structure, or the reticulated shell structure can be combined with the floating structure to form a floating latticework. The lattice structure and the floating structure share the same importance. The lattice structure and the floating structure can be combined in two ways. 
         [0108]    In a first manner, the lattice structure is disposed on one or more uniformly-distributed floating structures and fixedly connected to steel plates on the floating structures by welding or by bolts. This combining manner is the same as that of an ordinary lattice structure when being supported on upright posts. Particularly, the floating latticework is supported on the floating structure, and is connected to the floating structures in the same manner as that of fixedly connecting the ordinary lattice structure to the supporting structure (it should be noted that, all the configurations of “being disposed on and fixedly connected to the floating structure” mentioned below are achieved in the above manner, and the configurations of “being fixedly connected” mentioned below are all achieved by welding or by bolts). Among the lattice structures, both the grid structure and the lattice truss structure are plate-shaped spatial structures, except that the cross sections of rod members thereof and structures of joints thereof are different from each other. Herein, since the grid structure and the lattice truss structure are combined with the floating structure based on the same principles and their implementation manners are substantially the same, the grid structure and the lattice truss structure are illustrated together by taking the grid structure as an example, and the accompanying drawings also take the grid structure as an example. Persons skilled in the art can easily know the implementation manners of the lattice truss structure based on that of the grid structure. For example, when the grid structure is replaced by the lattice truss structure, circular joint members are replaced by joints welded by steel plates, and the combining process is replaced by fixedly connecting by bolts or by welding. The reticulated shell structure is combined with the floating structure based on the same principles as that of the grid structure, and the implementation manners of the reticulated shell structure are substantially the same as that of the grid structure. However, since the reticulated shell structure and the grid structure have different spatial structures, they are illustrated separately. 
         [0109]    A grid structure or a lattice truss structure is disposed on one or more uniformly-distributed floating structures and fixedly connected to steel plates on the floating structures at lower chord joints thereof. When there is one floating structure, the floating structure may be a flat-plate-shaped or          -shaped floating structure. When there is a plurality of floating structures, the floating structures may be spherical floaters, buoyant boxes, hollow columnar floating drums, or foamed plastic floaters, and may be uniformly distributed at positions of lower chord joints of the grid structure or the lattice truss structure. Referring to  FIG. 1 , a grid structure  1  is disposed on and fixedly connected to a plurality of columnar or hollow columnar floating structures  2  ( FIG. 1  is also an accompanying drawing for claims  6 - 7  that are illustrated below). 
         [0110]    Among the reticulated shell structures, an arched transparent rigidly-covered double-layer reticulated shell structure such as a spherical domed reticulated shell is most preferred to be combined with the floating structure, and meanwhile, a columnar double-layer reticulated shell is less preferred. Referring to  FIG. 2 , a transparent rigidly-covered double-layer spherical domed reticulated shell  1  is disposed on and combined with a flat-plate-shaped very large floating structure (VLFS)  2 . The flat-plate-shaped VLFS  2  is a floating grid structure. Peripheral joints at the lowest points of the domed reticulated shell  1  are fixedly connected to the floating structure ( FIG. 2  is also an accompanying drawing of claim  13 ). A space between the domed reticulated shell structure and the flat-plate-shaped VLFS is used as a living or operating space above water. When it is selected that there is a plurality of floating structures such as a plurality of buoyant boxes, ball floats, or floating drums, the floating structures are distributed at and fixedly connected to the peripheral joints of the reticulated shell. Referring to  FIG. 30 , a double-layer cylindrical-surface reticulated shell structure  1  is disposed on and fixedly connected to two floating structures  2  ( FIG. 30  is a schematic view of a floating double-layer cylindrical-surface reticulated shell structure used as a supporting structure for a floating bridge). 
         [0111]    In a second manner of combining the lattice structure with the floating structure, there is a plurality of floating structures. When the lattice structure is under a maximum design load, members that are submerged or semi-submerged in water are combined with and fixedly connected to the floating structures. For example, when a grid structure, a lattice truss structure, or a reticulated shell structure is under a maximum load, rod members and joint members that are submerged or semi-submerged in water are combined with and fixedly connected to the floating structures. The maximum load refers to a self weight plus a maximum load capacity, and furthermore, the self weight and an additional load caused by wind, rain, and snow are not counted into the load capacity of an arched reticulated shell structure. The rod members and the joint members may be combined with the floating structures in different manners. Referring to  FIG. 3 , the floating structures  3  are connected to the rod members  1  of the lattice structure by binding. Referring to  FIG. 4 , a coiled foamed plastic floater  3  is used to wrap around a rod member  1 . Referring to  FIG. 5 , a coiled foamed plastic floater  3  is used to wrap around a joint  2 . Referring to  FIG. 6 , coiled foamed plastic floaters  3  are used to wrap around rod members  1 , and meanwhile a joint  2  is fixedly connected to a columnar floater  4 . The above manner of fixedly connecting the joint  2  to the columnar floater  4  is similar to the first manner of combination. If the lattice structure is designed as a suspending state, all the members constituting the lattice structure may be combined with and fixedly connected to the floating structures. If the lattice structure is designed as a floating or semi-submerged state, a part of the members, i.e., the members that are submerged or semi-submerged in water under the maximum load, are combined with and fixedly connected to the floating structures. Among the members that are located above the water surface, only some of them are required to be combined with the floating structures in consideration of the safety factor, and the rest does not need to be combined with the floating structures. For a grid structure or a lattice truss structure, web members, lower chord rods, and lower chord joints may be designed to be submerged or semi-submerged in water. For an arched reticulated shell structure, members at a lower end portion of the reticulated shell structure may be designed to be submerged in water. Some or all of the members that are designed to be submerged or semi-submerged in water are respectively combined with the floating structures. For the grid structure or the lattice truss structure, at least one kind of members selected from a group consisting of the web members, the lower chord rods, and the lower chord joints are respectively combined with the floating structures, which is determined depending upon a magnitude of a required buoyant force and a size of the floating structures. 
         [0112]    The members at a lower peripheral portion of the spherical domed reticulated shell designed to be submerged in water are all combined with and fixedly connected to the floating structures in a manner as shown in  FIG. 3 ,  4 ,  5 , or  6 . A space formed between such a floating reticulated shell structure and the water surface is used as a seaside resort, a water amusement park, or an offshore operating space for protection against sunlight, wind, and rain. When a cylindrical or square-columnar double-layer reticulated shell is combined with a floating structure, for example, as for a cylindrical or square-columnar double-layer reticulated shell with an axis thereof being parallel to the horizontal plane, members thereof that are submerged in water may also be respectively combined with and fixedly connected to the floating structures in a manner shown in  FIG. 3 ,  4 ,  5 , or  6 . The cylindrical or square-columnar double-layer reticulated shell horizontally floats above water, and may serve as a supporting structure for an above-water passage. 
         [0113]    The above two manners can be used together. That is to say, if the lattice structure cannot be floated after implementing according to the above first manner, the second manner of combination can be used at the same time. 
         [0114]    The two manners of combining the lattice structure with the floating structure are illustrated in further detail in the implementations of claims  3 - 15 . The two manners of combination aim at utilizing the buoyant forces of the floating structures to enable the lattice structure to float above water or to maintain one of the floating, semi-submerged, and suspending states. 
         [0115]    2. When it is selected that the lattice structure is a grid structure or a lattice truss structure, the grid structure includes various grid structures, such as an ortho-laid quadrangular pyramid grid, a two-way orthogonal obliquely-placed quadrangular pyramid grid, a three-way grid, a hollowed triangular pyramid grid, a thickening grid, and a double-layer grid. The lattice truss structure includes various lattice truss structures, such as a thickening lattice truss structure and a double-layer lattice truss structure (the illustrations in this paragraph have already been given hereinabove; however, since there are 51 claims, the illustrations are given herein again for the purpose of making demonstrations one by one corresponding to each claim, so does the content below). 
         [0116]    3. When it is selected that the lattice structure is a grid structure or a lattice truss structure disposed on and fixedly connected to a floating structure, the floating structure is a          -shaped floating structure. The term          shaped” refers to a physical configuration of the floating structure as a          -shaped hollowed lattice structure. Referring to  FIG. 7 , a watertight          -shaped shell cavity is welded by steel plates. The lattice size of the          -shaped structure is equal to or integral multiples (for 2-4 times) of that of the grid structure or the lattice truss structure. Lower chord joints of the grid structure or the lattice truss structure correspond to joints of the          -shaped floating structure, and the grid structure or the lattice truss structure is fixedly connected to the          -shaped floating structure at the joints. Joints of a          shape configuration refer to crossing points where the lattices are crossed with each other. As for a small lattice truss structure, no special joint members are provided. In this case, the joints refer to meeting points of truss rods, and the lower chord joints of the lattice truss structure refer to meeting points of lower chord rods. 
         [0117]    4. A skeleton of the          -shaped floating structure is a hollowed grid structure or a hollowed lattice truss structure. The grid structure or the lattice truss structure, except for hollowed portions thereof, is covered with and welded to steel plates to form a          -shaped structure. The steel plates are seal-welded, and a space covered by the steel plates for enclosing the grid structure or the lattice truss structure is watertight. When a ratio of a width to a height of a cross section of the          shaped structure is smaller than 3, that is, a/b&lt;3, the skeleton is preferably a hollowed lattice truss structure as shown by a partial cross-sectional view of  FIG. 7 . When a/b&gt;3, a hollowed grid structure is preferably used. 
         [0118]    5. Referring to  FIG. 1 , when it is selected that the lattice structure is a grid structure or a lattice truss structure and a plurality of floating structures  2  is uniformly distributed at lower chord joints of the grid structure or the lattice truss structure  1 , one floating structure is disposed at one joint, or one floating structure is disposed at every two or more than two joints. Each floating structure is preferably disposed at one joint. 
         [0119]    6. Such a floating structure may be a hollow ball float, buoyant box, and columnar floating drum with a steel plate structure, and may also be a spherical, cubic, cylindrical, or square-columnar floater made of foamed plastics, among which a cylindrical foamed plastic floater is preferred. When a cylindrical foamed plastic floater is used, since the GFRP wrapping around the foamed plastic floater is not firmly connected to members of the lattice structure, a connecting piece as shown in  FIG. 8  needs to be fabricated, in which a plurality of reinforcing bars  2  is welded to a steel plate  1  and a steel ring  3 . When it is intended to wrap the GFRP around the foamed plastics, the connecting piece is sleeved on the cylindrical foamed plastic floater, and the reinforcing bars and the steel ring are used to wrap and fixed within the GFRP. If the foamed plastic floater is spherical or box-shaped, shapes of the reinforcing bars  2  and the steel ring  3  of the connecting piece shall match with the spherical or box-shaped floater. 
         [0120]    7. Referring to  FIG. 1 , since the columnar floating structures are fixedly connected to the lattice structure at top portions thereof, the bottoms thereof may swing along with waves, and thus, the bottoms of the columnar floating structures are respectively provided with beckets  4  for tying with fastening ropes or reinforcing bars. Three to four ropes or reinforcing bars  3  are fastened to the beckets and the lower chord joints of the lattice structure in an inclined radial manner, so as to position the bottoms of the columnar floating structures. 
         [0121]    8. When it is selected that the lattice structure is a grid structure or a lattice truss structure, the floating latticework includes a plurality of floating structures such as a plurality of foamed plastic floaters, coiled polystyrene foam plastics, and steel-structure cylindrical floating drums provided with a plurality of beckets for tying with fastening ropes or reinforcing bars, and members of the lattice structure are respectively combined with and fixedly connected to the floating structures, at least one kind of members selected from a group consisting of web members, lower chord rods, and lower chord joints of the grid structure or the lattice truss structure is combined with and fixedly connected to the floating structures. The combining process may be implemented in any manner, for example, referring to  FIG. 3 ,  4 ,  5 , or  6 , the floating structures may be bound to the members, wrap around the members, or fixedly connected to the members, as long as the floating structures are connected to the members to enable the members and the lattice structure assembled thereby to have a buoyant force and to enable the lattice structure to become a floating structure. When the floater is a cylindrical floating drum as shown in  FIG. 6 , an upper portion of the floating drum is fixedly connected to a joint, and the bottom of the floating drum is welded with a plurality of beckets  5  for tying with ropes  6 , such that the bottom of the floating drum is fixed as shown in  FIG. 1 . When the lattice structure floats above water, the steel members constituting the lattice structure may rust, so the steel members need to be sprayed with a protective layer, for example, sprayed with plastics. 
         [0122]    9. Referring to  FIGS. 4 and 5 , the floating structure may be combined with the members of the lattice structure by wrapping. The floating structures  3  are used to wrap around at least one kind of members selected from a group consisting of the web members, the lower chord rods, and the lower chord joints of the grid structure or the lattice truss structure. The floating structures used to wrap around the members of the grid structure or the lattice truss structure may be foamed plastic floaters. Referring to  FIG. 4 , a coiled foamed plastic  3  wraps around a rod member  1 , and meanwhile it is bound by a plurality of ropes. Referring to  FIG. 5 , a foamed plastic floater  3  partially wraps around a lower chord joint  2  of the grid structure, and a plurality of ropes fixed on the foamed plastic floater  3  is fastened to lower chord rods  1 , such that the floater is fixedly attached to the lower chord joint  2  and the lower chord rods  1 . When the GFRP is used to wrap the foamed plastic floater  3 , the ropes are used to wrap and fixed in the GFRP. 
         [0123]    10. Referring to  FIGS. 9 and 10 , the floating structure for wrapping around a rod member  1  of the grid structure or the lattice truss structure may also be a hollow cylindrical or square-columnar floating member  2 . The hollow cylindrical floating member may adopt a watertight steel plate structure  2  as shown in  FIG. 9 , or a hollow columnar floating member  2  made of foamed plastics as shown in  FIG. 10 , which has a cross section at a hollow portion thereof the same as that of the rod member. As for the grid structure, the cross section at the hollow portion is circular. As for the lattice truss structure, if truss rods are angle steels, the cross section at the hollow portion is an angle steel cross section. In the figure, a circular cross section at the hollow portion is taken as an example. The hollow columnar floating members are sleeved on at least one kind of rod members selected from the web members and the lower chord rods before assembling the members of the lattice structure. Two ends of the hollow columnar floating member  2  are respectively provided with a bolt  3  for fixing. 
         [0124]    11. When it is selected that at least one kind of rod members selected from the web members and the lower chord rods of the grid structure or the lattice truss structure is combined with the floating structures, as shown in  FIG. 11 , each of the floating structures is a hollow columnar floating structure formed by combining two half shells  2  together. A cross-sectional shape at a hollow portion of the hollow columnar floating structure is the same as that of the selected rod member  1  when the two half shells are combined together. As for the grid structure, the cross section at the hollow portion is circular. As for the lattice truss structure, if truss rods are square tubes, the cross section at the hollow portion is square. In the figure, a circular cross section at the hollow portion is taken as an example. During assembly, each two half shells  2  are separated first and then jointly wrap around at least one rod member selected from the web member and the lower chord rod. The two half shells  2  are connected to each other by three to four hinges at two sides of a junction plane there-between, in which bolts  4  may be used as shafts of the hinges. Before assembly, the bolt  4  at one side is removed to separate the two half shells  2  from each other at one side, and then the bolt  4  is inserted again and screwed with a nut after the two half shells jointly wrap around the selected rod member  1 . The half shells  2  may have watertight steel plate structures. If the floating members  2  are made of foamed plastics, the two half shells may be bound together by steel wires or ropes. 
         [0125]    12. In the floating latticework according to claim  1 , the lattice structure is a reticulated shell structure, such as a three-way cylindrical-surface reticulated shell, a double-layer cylindrical-surface reticulated shell, a cylindrical or square-columnar double-layer reticulated shell, and a transparent rigidly-covered arched and domed reticulated shell. 
         [0126]    13. Referring to  FIG. 2 , the reticulated shell structure is a transparent rigidly-covered domed double-layer reticulated shell structure  1 , which is disposed on and fixedly connected to a flat-plate-shaped floating structure  2 . The flat-plate-shaped floating structure is a combination of a grid structure or a lattice truss structure with floating structures, in which the combining process is achieved as that described in claims  5 - 11 . The flat-plate-shaped floating structure may also be a floating grid structure with members thereof as floating members. Since the weight of the domed double-layer reticulated shell structure is mainly focused on a periphery of the flat-plate-shaped floating structure, a plurality of floaters  3  is additionally provided below the periphery of the flat-plate-shaped floating structure to balance the weight of the domed double-layer reticulated shell structure borne by the periphery of the flat-plate-shaped floating structure. A space formed between the domed double-layer reticulated shell structure and the flat-plate-shaped floating structure is used as a living or operating space. Referring to  FIG. 12 , a transparent rigidly-covered domed double-layer reticulated shell structure  1  is disposed on and fixedly connected to an annular floating structure  2 . The annular floating structure is formed by combining an annular grid structure with floaters according to a manner described in claims  5 - 11 . The annular floating structure may also be an annular truss structure or an annular cylindrical-surface reticulated shell structure with foamed plastic floaters filled in a space between internal and external members thereof. A space formed between the domed double-layer reticulated shell structure and the water surface is used as a seaside resort, a water amusement park, or an offshore operating space for protecting against sunlight, wind, and rain. 
         [0127]    14. Referring to  FIG. 13 , another floating latticework is provided, which includes a grid structure or a lattice truss structure  1  formed by rod members and joint members. An upper chord surface, a lower chord surface, and four side faces of the grid structure or the lattice truss structure  1  are covered with and fixedly connected to plate-shaped steel structures  2 . The plate-shaped steel structures may be steel plates, or steel plates welded with vertical and horizontal ribs, similar to a shipside of a ship. The steel plates covering the lower chord surface and the four side faces are seal-welded. A space formed by the steel plates for enclosing the grid structure or the lattice truss structure is watertight, that is, the whole steel plates used for covering are watertight. In this manner, a watertight floating spatial grid structure or a watertight floating spatial lattice truss structure is formed. 
         [0128]    15. Each of the plate-shaped steel structures may be a grid structure or lattice truss structure with one chord surface thereof covered with and fixedly connected to a steel plate, or may be a grid structure or lattice truss structure with a steel plate as one chord surface thereof. The lattice specification of the grid structure or the lattice truss structure constituting the plate-shaped steel structure is relatively smaller than that of the grid structure or the lattice truss structure covered by the plate-shaped steel structure, and a ratio there-between is 1/N, N&gt;2, and N is preferably 7, 8, or 9. 
         [0129]    16. Another floating latticework is provided, which includes a lattice structure assembled by members. The lattice structure includes a grid structure, a lattice truss structure, and a reticulated shell structure. The grid structure includes various grid structures, such as an ortho-laid quadrangular pyramid grid, a chessboard-shaped quadrangular pyramid grid, a three-way grid, a hollowed triangular pyramid grid, a thickening grid, a single-layer grid, and a double-layer grid. The lattice truss structure is not a common three-dimensional truss structure, but a special and regular lattice truss structure among the three-dimensional truss structures, and includes a single-layer or double-layer, uniform-thickness or thickening lattice truss structure, and a hollowed lattice truss structure. The reticulated shell structure includes, for example, a three-way cylindrical-surface double-layer reticulated shell, a spherical reticulated shell, a cylindrical or square-columnar double-layer reticulated shell, and a thickening reticulated shell. When the lattice structure is under the maximum design load, some or all of the members thereof are light-weight and large-volume members with such a high water displacement that a ratio of a sum of a self weight and a maximum load capacity of the lattice structure to a total volume of the members is smaller than 9800 N/m 3 . That is, these members are floating members. If some of the members are floating members, members that are submerged or semi-submerged in water are floating members. The lattice structure partially assembled by or completely assembled by floating members is a floating latticework. All the grid structures, lattice truss structures, or reticulated shell structures may also become a floating latticework, as long as members thereof are floating members with sufficient high buoyant forces. The maximum load refers to a self weight plus a maximum load capacity of the lattice structure, and furthermore, as for an arched reticulated shell structure, the self weight and an additional load caused by wind, rain, and snow are not counted into the load capacity of the arched reticulated shell structure.  FIG. 14  shows a floating grid structure.  FIG. 15  shows a floating cylindrical-surface reticulated shell structure.  FIG. 16  shows a floating cylindrical reticulated shell structure. Undoubtedly, regardless of the grid structure, the lattice truss structure, or the reticulated shell structure, the floating members thereof means that members of the lattice structure that are designed to be submerged or semi-submerged in water are floating members (among the members that are located above water surface, only some of them are floating members in consideration of the safety factor, and the rest does not need to be floating members). For example, as for a grid structure or a lattice truss structure, web members, lower chord rods, and lower chord joints may be designed as members that are submerged or semi-submerged in water. As for an arched reticulated shell structure, members at a lower end portion of the reticulated shell structure may be designed as members that are submerged in water. Some or all of the members that are designed to be submerged or semi-submerged in water may be floating members. As for the grid structure or the lattice truss structure, at least one kind of members selected from a group consisting of the web members, the lower chord rods, and the lower chord joints may be floating members, which is determined depending upon a magnitude of a required buoyant force. A process of making a member into a floating member is described as follows. A floating rod member may take a large-diameter watertight hollow columnar structure or a three-dimensional truss structure with foamed plastic floaters filled therein as a main body structure, except for connecting devices at two ends thereof. A joint member may take a large-diameter watertight hollow spherical structure, a watertight hollow cubic structure, or a watertight hollow variant structure as a main body structure to increase the water displacement, except for devices thereon for connecting to the rod members. The large-diameter watertight hollow spherical structure and the watertight hollow variant structure are suitable for being used as a main body structure for a floating joint member of a floating grid structure, and the connecting devices thereon are grid joint connecting devices. The large-diameter watertight hollow spherical structure and the watertight hollow cubic structure are suitable for being used as a main body structure for a floating joint of a floating lattice truss structure, and connecting devices thereon are lattice truss joint connecting devices. Shell walls of the watertight hollow columnar structure, the watertight hollow spherical structure, and the watertight hollow variant structure are steel plates, double-layer reticulated shell structures rigidly covered by GFRP or steel plates, or reinforcing bar grid structures filled with foamed plastics therein and coated with cement grouts externally. The lattice structure partially assembled by or completely assembled by the floating members is a floating latticework, which can maintain a semi-submerging, floating, or suspending state in water. Both the floating rod members of the floating grid structure and that of the floating lattice truss structure may be circular or square-shaped hollow columns. However, as for the floating grid structure, the connecting devices at two ends thereof are connecting devices for the grid rod member, and as for the floating lattice truss structure, the connecting devices are connecting devices for the lattice truss. Structures of the rod members and the joint members are large in size, but structures of the connecting devices thereon and the connection manners thereof are the same as a common grid structure or lattice truss structure, but merely the structural size is enlarged accordingly. 
         [0130]    17. The structure assembled by the floating members is a grid structure or a lattice truss structure. The grid structure includes various grid structures, such as a star-shaped quadrangular pyramid grid, an obliquely-placed quadrangular pyramid grid, a honeycomb-shaped triangular pyramid grid, a two-way orthogonal obliquely-placed grid, a thickening grid, a single-layer grid, and a double-layer grid. The lattice truss structure is not a common three-dimensional truss structure, but a special and regular lattice truss structure among the three-dimensional truss structures, and includes a single-layer or double-layer, uniform-thickness or thickening lattice truss structure, and a hollowed lattice truss structure. Rod members and joint members of the grid structure or the lattice truss structure that are submerged or semi-submerged in water are light-weight and large-volume members with such a high water displacement that a ratio of a sum of a self weight and a load capacity of the lattice structure to a total volume of the members is smaller than 9800 N/m 3 . The grid structure or the lattice truss structure assembled by the floating members is a floating grid structure or a floating lattice truss structure, as shown in  FIG. 14 . 
         [0131]    18. At least one kind of members selected from a group consisting of lower chord joints, lower chord rods, and web members of the floating grid structure or the floating lattice truss structure is floating members. 
         [0132]    19. Referring to  FIG. 17 , when it is selected that the lower chord joints of the floating grid structure or the floating lattice truss structure are floating members, the floating members are provided with connecting devices  3  thereon for connecting to the lower chord rods  1  and the web members  4 . The connecting devices  3  are grid joint connecting devices as for the grid structure and are lattice truss joint connecting devices as for the lattice truss structure. Such connecting devices are the same as that of a common lattice structure, which thus are not illustrated in detail below and are further omitted in the figure. The lower chord joints may be variants  2  that are floating members protruding underwater from the floating grid structure or the floating lattice truss structure assembled thereby, which may be circular truncated cone-shaped, cylindrical-shaped, or cone-shaped. The extent and volume for the floating members to protrude underwater are determined depending upon such a criteria that the water displacement thereof can provide a sufficient buoyant force to the grid structure or the lattice truss structure, thereby enabling the grid structure or the lattice truss structure to maintain a semi-submerged, floating, or suspending state in water. 
         [0133]    20. Referring to  FIG. 18 , when it is selected that in the floating grid structure or the floating lattice truss structure, the web members are all arranged in an inclined manner and the lower chord joints are floating members, the lower chord joints are variants  2  provided with connecting devices  3  at a waist portion thereof for connecting to the lower chord rods  1  and the web members  4 . The variants may also be floating members  2  with upper portions thereof perpendicular to the water surface being cylindrical-shaped and lower portions thereof protruding underwater from the grid structure or the lattice truss structure assembled thereby. The portions protruding underwater may be cylindrical-shaped or circular truncated cone-shaped. 
         [0134]    21. Referring to  FIG. 19 , when it is selected that the floating grid structure or the floating lattice truss structure includes web members perpendicular to a horizontal plane, and the lower chord joints and the web members perpendicular to the horizontal plane are both floating members, the lower chord joints and the web members perpendicular to the horizontal plane are connected integrally and provided with connecting devices  3  for connecting to the lower chord rods  1  and the web members  4  as well as connecting devices  5  for connecting to upper chord joints. The diameter and length of the web members perpendicular to the horizontal plane are larger than that of the original web members. The lower chord joints and the web members perpendicular to the horizontal plane are assembled into floating members  2  protruding underwater from the floating grid structure or the floating lattice truss structure assembled thereby. The portions protruding underwater may be cylindrical-shaped or circular truncated cone-shaped. 
         [0135]    22. In the floating latticework according to any one of claims  18 - 21 , the floating members are provided with devices for connecting to the joints or rod members. The connecting devices are grid joint connecting devices as for the grid structure, and they are lattice truss joint connecting devices as for the lattice truss structure. Main bodies of the floating members are watertight hollow shell structures. As for floating rod members, main bodies thereof are watertight hollow cylindrical or square-columnar structures; as for floating joints, main bodies thereof are watertight hollow spherical structures; and as for floating variants, main bodies thereof are watertight hollow variant structures. Shell walls of the watertight hollow columnar structures, the watertight hollow spherical structures, and the watertight hollow variant structures are steel plates, double-layer reticulated shell structures rigidly covered by steel plates, or reinforcing bar grid structures filled with foamed plastics therein and coated with cement grouts externally. Shell walls formed by such three structures are all watertight. If the walls are steel plates, they are welded with vertical and horizontal ribs on inner sides. Such three structures are provided with steel structures at the devices for connecting to the joints for the purpose of reinforcement, so as to bear the compressive force and pulling force from the rod members. 
         [0136]    23. Referring to  FIG. 20 , when it is selected that at least one kind of rod members selected from the web members and the lower chord rods of the floating grid structure or the floating lattice truss structure is floating members, the floating members are provided with devices  3  at two ends thereof for connecting to the joints, and main bodies thereof may be three-dimensional truss structures  1  with a triangular, square, or rectangular-shaped cross section (A three-dimensional truss structure with a square-shaped cross section is taken as an example in the figure) and filled with foamed plastic floaters  2  therein, in which the cross section is preferably square or rectangular-shaped. The cross section of the lower chord rods is preferably rectangular-shaped, and the cross section of the web members is preferably square-shaped. The foamed plastic floater is configured as one block, has the same cross-sectional shape as that of the three-dimensional truss structure, and is filled into the space within the truss structure when the three-dimensional truss structure is mounted. 
         [0137]    24. When it is selected that the floating grid structure or the floating lattice truss structure has no lower chord rods, the entire lower chord surface of the floating grid structure or the floating lattice truss structure is a flat-plate-shaped floating structure or a          shaped floating structure. The flat-plate-shaped floating structure or the          shaped floating structure may be a watertight hollow steel plate structure with a skeleton thereof as a grid structure or a hollowed lattice truss structure, and may also be formed by assembling steel-structure buoyant box modules together. 
         [0138]    25. Referring to  FIG. 21 , the lower chord joints of the floating grid structure or the floating lattice truss structure are fixedly connected to floating structures  2 . The floating structure  2  may be a hollow ball float, buoyant box, and columnar floating drum with a steel plate structure, and may also be a spherical, cubic, cylindrical, or square-columnar floater made of foamed plastics, among which a cylindrical floater is preferred. The floating structures are located below the joints. It aims at increasing the buoyant force to fixedly connect the joints to the floating structures. 
         [0139]    26. Referring to  FIG. 22 , a floating latticework is provided, which includes a grid structure or a lattice truss structure. The grid structure or the lattice truss structure is filled with foamed plastics  2  therein. An upper chord surface of the lattice structure or the lattice truss structure  1  is a plate-shaped structure or is covered with a plate-shaped structure. The plate-shaped structure is a steel plate structure, or a reinforcing bar grid structure filled with foamed plastics therein and coated with cement grouts externally. There are two manners for filling the foamed plastics. In one manner, the foamed plastics are cut into long columns with a triangular-shaped cross section (as for the lattice truss structure, the cross section thereof is square or rectangular-shaped), and then filled into the spaces of the grid structure. In the other manner, plate-shaped foamed plastics with a thickness smaller than the height of the grid structure or the lattice truss structure for two rod diameters is obtained. Inclined holes are drilled in the plate-shaped foamed plastics for mounting the web members. Alternatively, the web members are directly penetrated through the foamed plastics, so as to be mounted. When the grid structure or the lattice truss structure is mounted, the plate-shaped foamed plastics are clamped therein and mounted. After the foamed plastics have been filled, the lower chord surface and the four sides of the grid structure or the lattice truss structure are wrapped with the GFRP. Alternatively, the foamed plastics are wrapped with the GFRP before filling. 
         [0140]    27. In the floating latticework according to any one of claims  2 - 11 ,  17 - 21 , and  23 - 26 , an upper chord surface of any one of the grid structure, the floating grid structure, the lattice truss structure, and the floating lattice truss structure is a plate-shaped structure. The plate-shaped structure may be a reinforced concrete plate, or a steel plate welded with vertical and horizontal ribs, similar to a deck or a shipside of a ship. 
         [0141]    28. The plate-shaped structure may also be a plate-shaped star-shaped quadrangular pyramid grid, an obliquely-placed quadrangular pyramid grid, a honeycomb-shaped triangular pyramid grid structure, or a plate-shaped lattice truss structure. The lattice specification of the plate-shaped structure is 1/N (N&gt;2, and N is preferably 7, 8, or 9) of that of the grid structure, the floating grid structure, the lattice truss structure, or the floating lattice truss structure covered by the plate-shaped structure. An upper chord surface of the plate-shaped grid structure or plate-shaped lattice truss structure is a steel plate structure. 
         [0142]    29. In the floating latticework according to any one of claims  2 - 11 ,  17 - 21 , and  23 - 26 , the grid structure, the floating grid structure, the lattice truss structure, and the floating lattice truss structure are respectively a hollowed grid structure, a hollowed floating grid structure, a hollowed lattice truss structure, and a hollowed floating lattice truss structure. A hollowed structure may be regularly or irregularly hollowed out. The hollowing process aims at covering a larger water surface with the same material consumption. 
         [0143]    30. Another floating latticework is provided, which mainly includes a frame structure. An integral frame structure formed by watertight hollow columns welded by steel plates or cast by the reinforced concrete may be used. If the watertight hollow columns are welded by steel plates, the steel plates may be welded with vertical and horizontal ribs on inner sides. Such a frame structure is a floating frame structure in such a specification that a ratio of a sum of a self weight and a load capacity thereof to a volume thereof is smaller than 9800 N/m 3 , as shown in  FIG. 23 . 
         [0144]    31. Referring to the partial cross-sectional view of  FIG. 23 , the floating frame structure may also be designed as follows. Upright posts and crossbeams of the floating frame structure are formed by a three-dimensional truss structure  1  with a square or rectangular-shaped cross section. The three-dimensional truss structure is externally covered with and welded to steel plate structures  2 , such that the upright posts and the crossbeams covered with and welded to steel plates are watertight when being submerged in water. Alternatively, the three-dimensional truss structure is filled with foamed plastic floaters therein. Referring to  FIG. 20 , it shows a main body of a rod member, and in this case, the foamed plastic floaters are filled into the space within the truss structure when the three-dimensional truss structure is mounted. 
         [0145]    32. Another floating latticework is provided, which includes a plurality of columnar floating structures with square or rectangular-shaped cross sections. The columnar floating structures are watertight hollow structures welded by steel plates, and the steel plates may be welded with vertical and horizontal ribs on inner sides. Alternatively, the columnar floating structures are watertight hollow structures cast by the reinforced concrete. Alternatively, the columnar floating structures are three-dimensional truss structures with a rectangular-shaped cross section and filled with foamed plastic floaters, in which the three-dimensional truss structures are externally sprayed with plastics or wrapped with the GFRP. Two end faces and two or three side faces of each columnar floating structure are provided with a plurality of connecting pieces. The connecting pieces are steel plates. When they are connected by welding, the welding process is performed at the steel plates. When they are fixedly connected by bolts, corresponding holes and bolt holes are provided on the steel plates. End faces and side faces of the columnar floating structures are fixedly connected to each other to form a          -shaped floating lattice structure or a floating frame structure that can float above water. When it is intended to form a          -shaped floating lattice structure, the connecting pieces on two side faces are respectively located at two ends of each side face or at the center of each side face. The columnar floating structures may be connected with each other in two manners. In the first manner, when the connecting pieces on the side faces are respectively located at the two ends of each side face, the columnar floating structures are connected to form a          shaped floating lattice structure, and a lattice specification for the          -shaped floating lattice structure is approximately equal to a length of the columnar floating structures. In the second manner, when the connecting pieces on the side faces are respectively located at the center of each side face, the columnar floating structures  1  are connected in a manner shown in  FIG. 24  to form a          -shaped floating lattice structure, and a lattice specification for the          -shaped floating lattice structure is ½ of the length of the columnar floating structures. The connection rigidity of the second manner is greater than that of the first manner. When it is intended to form a floating frame structure, the connecting pieces on three side faces are respectively located at the center of each side face, and the columnar floating structures are assembled in the second manner to form a          -shaped floating structure or construct an integral          -shaped floating structure. Then, floating columnar upright posts are fixedly connected at joints of the          -shaped floating structure. Then,          -shaped structures are fixedly connected to the upright posts and assembled in the second manner to serve as crossbeams, thereby forming a floating frame structure. Alternatively, an integral crossbeam structure is formed above the upright posts by a three-dimensional truss structure and fixedly connected to the upright posts, thereby forming a floating frame structure. 
         [0146]    33. A use of the floating latticework according to any one of claims  2 - 11 ,  14 - 15 ,  17 - 21 ,  23 - 26 , and  30 - 32  is provided. If an upper chord surface or an upper plane of the floating latticework is a plate-shaped structure, the upper chord surface or the upper plane is used as a supporting surface, and otherwise, the upper chord surface or the upper plane is covered with and fixedly connected to a steel plate structure or a reinforced concrete plate structure to serve as a supporting surface. The floating latticework is adapted to serve as a floating supporting structure for offshore floating projects such as water transportation, offshore buildings, offshore plants, offshore floating platforms, offshore drilling platforms, offshore airports, floating wharfs, artificial islands, and floating cities. Claims  14 - 15  and  26  are suitable for being used as a supporting structure for the water transportation. Claims  8 - 11 ,  14 - 15 , and  26  are suitable for being used as a floating platform. Claims  17 - 21  and  23 - 25  are suitable for being used as a supporting structure for offshore airports. The multi-layer (for example, four-layer or five-layer) floating grid structure in claim  17  is suitable for being used as the floating wharf. Claims  2 - 7 ,  17 - 21 ,  23 - 25 , and  31 - 33  are suitable for being used as a supporting structure for artificial islands and floating cities. 
         [0147]    34. Referring to  FIG. 25 , a use of the floating latticework according to any one of claims  2 - 11 ,  14 - 15 ,  17 - 21 ,  23 - 26 , and  30 - 32  is provided. A floating grid structure  2  is taken as an example in the figure. If an upper chord surface or an upper plane of the floating grid structure  2  is a plate-shaped structure, the upper chord surface or the upper plane is used as a supporting surface, and otherwise, the upper chord surface or the upper plane is covered with and fixedly connected to a steel plate structure or a reinforced concrete plate structure to serve as a supporting surface. Square steel tubes, round steel tubes, or three-dimensional trusses are fixedly connected on the supporting surface to serve as upright post support structures  1 . Truss structures are taken as an example in the figure. Vertical planes formed by a plurality of upright posts to serve as wall surfaces are covered with and fixedly connected to glass plates or colored steel plates to serve as wall bodies. The upright post support structures  1  are covered with and fixedly connected to an ortho-laid quadrangular pyramid grid, a chessboard-shaped quadrangular pyramid grid, a three-way grid structure, a lattice truss structure, or a cylindrical-surface reticulated shell structure  3  there-above. A grid structure is taken as an example in the figure. The grid structure, the lattice truss structure, or the cylindrical-surface reticulated shell structure is covered with and fixedly connected to GFRP roofing slates, colored steel roofing slates, or transparent plastic plates by bolts to serve as a roof, thereby forming a living space above water. Buildings formed by light steel structures may be built within this living space. 
         [0148]    35. A use of the floating latticework according to any one of claims  2 - 11 ,  17 - 21 , and  23 - 26 , adapted to serve as a supporting structure for a floating bridge, is provided. A grid structure is taken as an example in  FIGS. 26 and 27 . Referring to  FIGS. 26 and 27 , an upper chord surface of a floating grid structure  2  is covered with and fixedly connected to a bridge deck  1 . A plane axis of the floating grid structure  2  is consistent with that of the bridge deck  1 . The bridge deck  1  is supported by and fixedly connected to upper chord joints of the floating grid structure. Positioning ropes  3  connected to underwater bollards or caissons  4  (caissons are taken as an example in the figure) are provided at two axial sides of the floating grid structure  2 . A plurality of positioning ropes and underwater bollards or caissons may be provided, and the specific number thereof is determined in such a way that the floating bridge can overcome the maximum winds and waves in the water area where it is located.  FIG. 27  is a top view of a floating bridge. When being used as a supporting structure for a floating bridge, the floating grid structure or the floating lattice truss structure may adopt a thickening structure, which is thickened at the part covered by the bridge deck to increase the buoyant force and balance the load of the bridge. Such a floating bridge is applicable to straits. 
         [0149]    36. In the use of the floating latticework according to claim  35 , the floating latticework is adapted to serve as a supporting structure for a floating bridge, in which a planar shape of the floating latticework is          shaped or          shaped as shown in  FIGS. 28 and 29 . The          shaped or          shaped structure mainly aims at enlarging the covering surface of the floating latticework, so as to minimize the impacts caused by the waves. 
         [0150]    37. Referring to  FIG. 30 , a use of the floating latticework according to claim  1  is provided, in which a lattice structure is a double-layer or multi-layer arched cylindrical-surface reticulated shell structure, and the floating latticework is adapted to serve as a supporting structure for a floating bridge. The arched cylindrical-surface reticulated shell structure is preferably a double-layer or three-layer structure. A double-layer arched cylindrical-surface reticulated shell structure is taken as an example in the figure. Two ends of an arched cylindrical-surface reticulated shell structure  1  are respectively fixed to two floating structures  2 . The floating structures may be box-shaped or columnar floating structures with rectangular-shaped cross sections. The length of the columnar floating structures is larger than the width of the bridge, for example, it is three times as long as the width of the bridge, so as to balance the bridge. An upper chord surface of the arched cylindrical-surface reticulated shell structure is covered with and fixedly connected to a bridge deck  3 , and the bridge deck  3  is supported by and fixedly connected to upper chord joints of the arched cylindrical-surface reticulated shell structure, thereby forming a floating bridge or a portion of a long-span floating bridge for ships to pass below an arched portion thereof. When being used as a portion of a long-span floating bridge, and the long-span floating bridge is formed by taking the floating latticework according to claim  35  as a supporting structure, an arched cylindrical-surface reticulated shell structure is directly supported on a floating grid structure or a floating lattice truss structure. In this case, the grid structures or the lattice truss structures at supporting positions are thickening grid structures or thickening lattice truss structures. The arched cylindrical-surface reticulated shell structure is supported by upper chord joints of the thickening grid structures or the thickening lattice truss structures. Among two ends of the arched cylindrical-surface reticulated shell structure at the supporting positions, one is fixedly connected, and the other is movably connected, so as to provide a horizontal displacement between the two structures. 
         [0151]    38. Referring to  FIG. 31 , a use of the floating latticework according to claim  16  is provided, in which a lattice structure is a double-layer or multi-layer columnar reticulated shell structure, and the floating latticework is adapted to serve as a supporting structure for a floating bridge. The columnar reticulated shell structure floats above water with an axis thereof being horizontal. A cross section of the columnar reticulated shell structure is circular, square, rectangular, or trapezoidal, among which rectangular and trapezoidal are preferred. A rectangular-shaped cross section with long sides thereof perpendicular to the water surface is taken as an example in the figure. The columnar reticulated shell structure may be a double-layer, three-layer, or four-layer structure, and a double-layer structure or a three-layer structure is preferred. A columnar double-layer reticulated shell structure is taken as an example in the figure. A double-layer reticulated shell structure  1  itself is a floating structure. When serving as a supporting structure for a floating bridge, an upper chord surface of the columnar double-layer reticulated shell structure  1  is disposed with and fixedly connected to a bridge deck  2 , and the bridge deck  2  is supported by and fixedly connected to upper chord joints of the reticulated shell structure  1 . The floating reticulated shell structure is provided with positioning ropes  4  connected to underwater bollards or caissons  3  (caissons are taken as an example in the figure) at two axial sides thereof. There may be a plurality of positioning ropes, underwater bollards, or caissons. The two axial sides of the floating reticulated shell structure are fixedly connected to balance wings  5  for preventing the reticulated shell structure from swaying left and right along with waves. The balance wings may adopt a balance wing structure of an aircraft carrier. A plurality of steel plates is fixedly connected to left and right sides at the bottom of the columnar reticulated shell structure. The steel plates are parallel to the water surface and welded with vertical and horizontal ribs thereon. The balance wings may also adopt truss structures as shown in  FIG. 5 . Each of the balance wings  5  is fixedly connected to a plurality of floaters  6  therebelow and the balance wings  5  are fastened to each other by ropes  7 . Each of the balance wings  5  may be configured above, at the center of, or below the side faces of the columnar reticulated shell structure, and each position has the specific advantages. Each of the balance wings  5  is most preferably configured at the center of the side faces of the columnar reticulated shell structure. Such a floating bridge is preferably applicable to interior rivers. 
         [0152]    39. A use of the floating latticework according to claim  14  or  15  is provided, in which the floating latticework is adapted to serve as a box-shaped or flat-plate-shaped floating structure, or as a main body structure of a liquid cargo ship such as an oil tanker. When being used as a main body structure of an oil tanker, the planar shape of the grid structure or the lattice truss structure is the same as that of the oil tanker. A covering plate thereof is as described in claim  15 . 
         [0153]    40. A floating reticulated shell structure is provided, which includes a single-layer, double-layer, or multi-layer spherical, box-shaped, columnar, or heterotypic hollow reticulated shell formed by rod members and joints. A cross section of the columnar reticulated shell structure is circular, square, rectangular, or trapezoidal, and two ends of the columnar reticulated shell structure are watertight. Peripheral members of the reticulated shell are covered with and welded to steel plates or fixedly connected to steel plates or GFRP plates by bolts, so as to form a rigidly-covered single-layer, double-layer, or multi-layer reticulated shell structure. A double-layer reticulated shell structure is most preferred. The double-layer reticulated shell structure suitably adopts a double-layer thickening reticulated shell, which is thickened at a position for bearing the largest force. The steel plates are seal-welded. If the GFRP or steel plates are fixedly connected by bolts, sealant or sealing rings are additionally disposed between the plates and the members, such that a space enclosed by the rigidly-covered reticulated shell structure is watertight. The reticulated shell structure is applied above water to serve as a watertight and rigidly-covered spherical floating reticulated shell structure, box-shaped floating reticulated shell structure, columnar floating reticulated shell structure, or heterotypic hollow floating reticulated shell structure. 
         [0154]    41. The reticulated shell is a watertight and rigidly-covered columnar double-layer or multi-layer reticulated shell structure. A cross section of the columnar reticulated shell structure is circular, square, rectangular, or trapezoidal. Long sides of the rectangular-shaped cross section are perpendicular to the water surface. An axis of the columnar reticulated shell structure is parallel to the water surface, and two axial sides of the columnar reticulated shell structure are fixedly connected to balance wings for preventing the floating reticulated shell structure from swinging back and forth along with waves. The balance wings are the same as that described in claim  38 . 
         [0155]    42. A floating reticulated shell structure is provided, which includes a single-layer, double-layer, or multi-layer reticulated shell formed by rod members and joints. Peripheral members of the reticulated shell are covered with and welded to steel plates to form a rigidly-covered single-layer, double-layer, or multi-layer reticulated shell structure. The reticulated shell structure is a ship-shaped reticulated shell structure. Referring to  FIG. 32 , a ship-shaped double-layer thickening reticulated shell structure thickened at the bottom thereof is preferred. Steel plates  1  are seal-welded, such that the ship-shaped reticulated shell structure  2  enclosed by the steel plates  1  is watertight. The reticulated shell structure is applied above water to serve as a watertight and rigidly-covered ship-shaped floating reticulated shell structure. 
         [0156]    43. A ship body structure is provided, which includes side and bottom skeletons. The side and bottom skeletons are double-layer or multi-layer ship-shaped reticulated shell structures. For an ordinary ship, a double-layer thickening reticulated shell structure that is thickened at the bottom of the ship is most preferred. For a large or very large ship, a three-layer reticulated shell structure is preferred. Alternatively, side skeletons are formed by a double-layer reticulated shell structure, and bottom skeletons are formed by a three-layer reticulated shell structure. Skeletons that need to be connected to the reticulated shell structure such as bulkhead skeletons and deck skeletons are all fixedly connected at joints of the reticulated shell structure. Inner bottom plates or side plates within the ship are fixedly connected to internal members of the reticulated shell structure. 
         [0157]    44. A ship body structure is provided, which includes side and bottom skeletons, bulkhead skeletons, and deck skeletons. The side and bottom skeletons are double-layer or multi-layer reticulated shell structures. Referring to  FIG. 32 , the bulkhead skeletons  3  are formed by an ortho-laid quadrangular pyramid grid, an obliquely-placed quadrangular pyramid grid, a three-way grid, or a lattice truss structure. Alternatively, both the bulkhead skeletons and the deck skeletons are formed by grid structures or lattice truss structures. The lattice specification of the grid structure or the lattice truss structure used as the deck skeletons is relatively small. The grid structures or the lattice truss structures used as the bulkhead skeletons and the deck skeletons as well as the reticulated shell structures used as the side and bottom skeletons are fixedly connected to each other at joints thereof. Inner bottom plates are welded to internal members of the reticulated shell structure. Alternatively, the inner bottom plates are fixedly connected to the internal members of the reticulated shell structure by bolts, and meanwhile, sealant or sealing rings are additionally disposed between the inner bottom plates and the internal members of the reticulated shell structure. 
         [0158]    45. A floating reticulated shell structure is provided, which includes a spherical, columnar, or ship-shaped, double-layer or multi-layer reticulated shell structure. The reticulated shell structure is filled with foamed plastics in a space between internal and external members thereof. Referring to  FIG. 33 , a spherical double-layer reticulated shell structure  1  is filled with foamed plastics  2  therein. Referring to  FIG. 34 , a columnar double-layer reticulated shell structure  1  is filled with foamed plastics  2  therein. Referring to  FIG. 35 , a ship-shaped reticulated shell structure  1  is filled with foamed plastics  2  therein. The foamed plastics may be filled through the manners as described in the detailed descriptions of claim  26 . For the columnar double-layer reticulated shell structure, the first filling manner may be used, in which the foamed plastics are cut into long columns with a triangular-shaped cross section, and then filled into the spaces of the reticulated shell structure. For the spherical or ship-shaped reticulated shell structure, the second filling manner may be used, in which plate-shaped foamed plastics are obtained, and then cut into curved foamed plastic plates that match with a partial curved surface of the spherical or ship-shaped reticulated shell structure and have a thickness smaller than that of the reticulated shell structure for two rod diameters. Inclined holes are drilled in the curved foamed plastic plates for mounting the web members. Alternatively, the web members are directly penetrated through the curved foamed plastic plates. When the reticulated shell structure is mounted, the curved foamed plastics are clamped and mounted therein. After the foamed plastics have been filled, the spherical or columnar reticulated shell structure is externally wrapped with the GFRP, or the ship-shaped reticulated shell structure is externally mounted with steel plates. 
         [0159]    46. Referring to  FIGS. 36 and 37 , a cofferdam structure is provided, which includes skeleton structures  1  and steel plates  2  watertightly covered around the skeleton structures  1 . An axis of the cofferdam structure is perpendicular to a horizontal plane. A horizontal cross section of the cofferdam structure is a circular, elliptic, rectangular, or square-shaped closed line. The cofferdam structure is optionally provided with horizontal pressure support structures therein. The surrounding skeleton structures  1  of the cofferdam structure are formed by a columnar double-layer reticulated shell structure with an axis thereof perpendicular to the horizontal plane. The columnar double-layer reticulated shell structure has a cross-sectional shape the same as that of the cofferdam structure. The term “columnar” means that a diameter or a major axis of the cross section of the cofferdam structure is generally smaller than the depth of the cofferdam structure, so that the cofferdam structure seems like a column, and the double-layer reticulated shell structure also seems like a column in shape. Although a large or very large cofferdam structure with a diameter larger than a depth thereof does not seem like a column in shape, it is still a reticulated shell structure and follows the same configuring principle, which also falls within the scope of the present invention. Since the cofferdam structure is subject to a small water pressure at an external upper portion thereof and subject to a large water pressure at an external lower portion thereof, the thickness of the skeleton structures for the reticulated shell structure and diameters of the rod members and joints are small at the upper portion and large at the lower portion. 
         [0160]    47. Another cofferdam structure is provided, which includes skeleton structures and steel plates for covering around the skeleton structures in a watertight manner. An axis of the cofferdam structure is perpendicular to a horizontal plane. A horizontal cross section of the cofferdam structure is rectangular or square-shaped. The cofferdam structure is optionally provided with horizontal pressure support structures therein.  FIG. 38  shows a cofferdam structure with a rectangular-shaped cross section. The surrounding skeleton structures  1  of the cofferdam structure are formed by an ortho-laid quadrangular pyramid grid, obliquely-placed quadrangular pyramid grid, three-way grid, or lattice truss structure with a chord surface thereof perpendicular to the horizontal plane. The horizontal pressure support structures  3  may be quadrangular pyramid grids, three-way grids, hollowed triangular pyramid grid structures, or lattice truss structures with chord surfaces thereof perpendicular to the horizontal plane. The horizontal pressure support structures are also perpendicular to the grid structure or the lattice truss structure serving as the skeletons supported thereby, and are fixedly connected to the grid structure or the lattice truss structure at joints thereof. 
         [0161]    48. Referring to  FIG. 39 , a cofferdam structure is provided, which includes skeleton structures and steel plates  2  for covering around the skeleton structures in a watertight manner. An axis of the cofferdam structure is perpendicular to a horizontal plane. A horizontal cross section of the cofferdam structure is rectangular or square-shaped in the middle and semicircular-shaped at two ends thereof. The cofferdam structure is optionally provided with horizontal pressure support structures therein. The horizontal pressure support structures are perpendicular to and support two straight-edge surfaces. The skeleton structures  1  at the two straight-edge surfaces of the cofferdam structure are formed by ortho-laid quadrangular pyramid grids, obliquely-placed quadrangular pyramid grids, three-way grids, or lattice truss structures with chord surfaces thereof perpendicular to the horizontal plane. Semicircular cylindrical-surface skeleton structures at two ends of the cofferdam structure are formed by semicircular cylindrical-surface double-layer or multi-layer reticulated shell structures. The number of layers of each reticulated shell structure corresponds to that of the grid structure or the lattice truss structure. When the grid structure or the lattice truss structure is a double-layer structure, the number of layers of the reticulated shell structure is three. The horizontal pressure support structures  3  may be ortho-laid quadrangular pyramid grids, three-way grids, hollowed triangular pyramid grid structures, or lattice truss structures with chord surfaces thereof perpendicular to the horizontal plane. The horizontal pressure support structures  3  are also perpendicular to the grid structures or the lattice truss structures serving as the skeletons supported thereby, and are fixedly connected to the grid structures or the lattice truss structures at joints thereof. 
         [0162]    49. A method for manufacturing and mounting the cofferdam structure according to claims  46 - 48  is provided. The method includes the following steps: mounting skeletons of a cofferdam structure on a platform; covering steel plates around the skeletons; optionally providing horizontal pressure support structures in the cofferdam structure; excavating earth from a ground surface underwater in a water area under construction, such that the ground surface underwater is recessed; sinking and mounting the cofferdam structure in position; inserting the steel plates at a periphery of a bottom end of the cofferdam structure deep into the ground surface underwater; filling an underwater concrete or other sealing materials outside the cofferdam structure at the ground surface underwater; and withdrawing water from the cofferdam structure. A cofferdam space enclosed by the steel plates is watertight. The platform is located in the water area under construction and is a floating platform formed by steel structure buoyant boxes or foamed plastics. The platform is positioned in the water area under construction by positioning ropes. The floating platform is provided with a hollowed structure at a center thereof, such that a horizontal surface of the hollowed portion is similar to and slightly larger than a horizontal cross section of the cofferdam structure. A temporary platform is built at the hollowed structure, and the skeletons of the cofferdam structure are assembled on the temporary platform by prefabricated rod members and joint members. The skeletons of the cofferdam structure are columnar double-layer reticulated shell structures with axes thereof perpendicular to a horizontal plane. As for a large or very large cofferdam structure with a rectangular or square-shaped cross section, skeletons at four sides thereof may be formed by an ortho-laid quadrangular pyramid grid, three-way grid, hollowed triangular pyramid grid structure, or lattice truss structure with a chord surface thereof perpendicular to the horizontal plane. As for a cofferdam structure with a horizontal cross section being rectangular or square-shaped in the middle and semicircular-shaped at two ends thereof, skeletons at two straight-edge surfaces of the cofferdam structure are formed by ortho-laid quadrangular pyramid grids, obliquely-placed quadrangular pyramid grids, three-way grids, or lattice truss structures with chord surfaces thereof perpendicular to the horizontal plane, and semicircular cylindrical-surface skeletons at two ends of the cofferdam structure are formed by semicircular cylindrical-surface double-layer reticulated shell structures. If the horizontal pressure support structures are required, the horizontal pressure support structures are ortho-laid quadrangular pyramid grids, three-way grids, hollowed triangular pyramid grid structures, or lattice truss structures with chord surfaces thereof perpendicular to the horizontal plane. In the step of covering the steel plates around the skeletons, the assembling process is carried out from the periphery of the bottom end of the cofferdam structure and gradually proceeds upwards along side faces of the cofferdam structure. As the mounting height increases, a plurality of ropes is fastened to the bottom end of the cofferdam structure and the other ends of the ropes are fastened to the platform. Then, the temporary platform is dismantled, such that the cofferdam structure falls into the hollowed structure at the center of the platform. By adopting a step-by-step sinking manner, the cofferdam structure is sunk to a height convenient for a person to perform the assembling process while standing on the floating platform. When the cofferdam structure reaches a predetermined height, the cofferdam structure is sunk and mounted in position. 
         [0163]    50. A method for manufacturing and mounting a cofferdam structure according to claims  46 - 48  is provided. The method includes the following steps: mounting skeletons of a cofferdam structure on a platform; covering steel plates around the skeletons; optionally providing horizontal pressure support structures in the cofferdam structure; excavating earth from a ground surface underwater in a water area under construction, such that the ground surface underwater is recessed; sinking and mounting the cofferdam structure in position; inserting the steel plates at a periphery of a bottom end of the cofferdam structure deep into the ground surface underwater; filling an underwater concrete or other sealing materials outside the cofferdam structure at the ground surface underwater; and withdrawing water from the cofferdam structure. A cofferdam space enclosed by the steel plates is watertight. The platform is located in the water area under construction and is formed by a central platform and a peripheral platform surrounding the central platform. The central platform is a floating platform formed by steel structure buoyant boxes, and the peripheral platform is a floating platform formed by steel structure buoyant boxes or foamed plastics. The platform is positioned in the water area under construction by positioning ropes. A horizontal surface of the central platform is similar to and slightly larger than a horizontal cross section of the cofferdam structure. The central platform is movably connected to the peripheral platform, such that the central platform and the peripheral platform are capable of moving up and down relative to each other. Before an assembling process, the central platform is slightly higher than the peripheral platform or is coplanar with the peripheral platform. A buoyant force of the floating central platform is adjusted by filling water therein. The skeletons of the cofferdam structure are assembled on the central platform by prefabricated rod members and joint members. The skeletons of the cofferdam structure are columnar double-layer reticulated shell structures with axes thereof perpendicular to a horizontal plane. As for a large or very large cofferdam structure with a rectangular or square-shaped cross section, skeletons at four sides thereof are formed by a quadrangular pyramid grid, three-way grid, hollowed triangular pyramid grid structure, or lattice truss structure with a chord surface thereof perpendicular to the horizontal plane. As for a cofferdam structure with a horizontal cross section being rectangular or square-shaped in the middle and semicircular-shaped at two ends thereof, skeletons at two straight-edge surfaces of the cofferdam structure are formed by ortho-laid quadrangular pyramid grids, obliquely-placed quadrangular pyramid grids, three-way grids, or lattice truss structures with chord surfaces thereof perpendicular to the horizontal plane, and semicircular cylindrical-surface skeletons at two ends of the cofferdam structure are formed by semicircular cylindrical-surface double-layer reticulated shell structures. If the horizontal pressure support structures are required, the horizontal pressure support structures are also ortho-laid quadrangular pyramid grids, three-way grids, hollowed triangular pyramid grid structures, or lattice truss structures with chord surfaces thereof perpendicular to the horizontal plane. The assembling process is carried out from a bottom of the cofferdam structure and gradually proceeds upwards along side faces of the cofferdam structure, and prefabricated steel plates for covering the reticulated shells are mounted at the bottom and side faces of the cofferdam structure, and a cofferdam space enclosed by the mounted steel plates is watertight. When the cofferdam structure is assembled to such a height that the cofferdam structure is capable of floating above water alone, the floating central platform is sunk by filling water therein, thus separated from the bottom of the cofferdam structure, and then removed. As the assembling process of the cofferdam structure continues and the height of the cofferdam structure increases, by means of filling water into the cofferdam structure, the cofferdam structure is sunk to a height convenient for a person to perform the assembling process while standing on the peripheral platform. When the cofferdam structure reaches a predetermined height, the cofferdam structure is filled up with water and thus sunk and mounted in position. A sealing material is filled outside the cofferdam structure at the ground surface underwater. After water is withdrawn from the cofferdam structure, structures in the bottom of the cofferdam structure are removed. 
         [0164]    51. A covering plate used in the floating reticulated shell structure, ship body structure, or cofferdam structure according to claims  40 - 44  and  46 - 48  is provided. The covering plate is a steel plate adapted to cover and be fixedly connected to a peripheral member of a reticulated shell, or adapted to cover and be fixedly connected to a          -shaped lattice structure that is formed by welding square tubes and is fixedly connected to the peripheral member of the reticulated shell with joints thereof corresponding to joints of the reticulated shell. The covering plates are prefabricated, a length and a width of the covering plates are equal to or integral multiples (for 2-3 times) of that of a lattice, and covering plates are flat-plate-shaped or curve-shaped. When the covering plate is a steel plate, it is connected to the peripheral member of the reticulated shell or the          -shaped lattice structure by seal-welding, or is fixedly connected to the peripheral member of the reticulated shell or the          -shaped lattice structure by bolts, and meanwhile a rubber sealing ring and a sealant is additionally disposed between the covering plate and the peripheral member of the reticulated shell or the          shaped lattice structure. When being fixedly connected by bolts, the covering plate may also adopt a high-strength GFRP plate.