Saddle-shaped semi-rigid cable net structure
Technical Field
The utility model belongs to the technical field of building engineering, a large-span venue building roof structure is related to, more specifically says and relates to a saddle-shaped semi-rigid cable net structure.
Background
The saddle surface is also called a hyperbolic paraboloid, is a curved surface generated by linear motion, and is provided with two groups of straight generatrixes; from the property of the hyperbolic paraboloid, any two heterogeneous straight generatrices on the curved surface are intersected. When the curved surface is stressed, any one straight bus can be shared by another group of straight buses, the structure is more stable due to interaction, and the hyperbolic paraboloid is used as the structural roof, so that good structural stress performance can be obtained. The saddle-surface roof has a simple and smooth appearance, and can obtain attractive architectural shapes when being used in large-span building structures such as stadiums, and the like, so that the saddle-surface roof is favored by designers and is increasingly applied to practical engineering.
In 1953, the saddle-shaped cable net structure was first adopted in the building of a Releigh gym in north carolina in the united states, which is not only the first suspension cable structure in the world, but also a great attempt to use the saddle surface for roof structures. In recent years, with the rapid development of the spatial structure in China, the saddle-shaped roof is used in a large-span steel structure, and the saddle-shaped roof is diversified in structure form, and is commonly in a cable net structure, a net shell structure, a net rack structure and the like.
The cable net structure is a structural form with the highest utilization rate of saddle-shaped roof covers, saddle-shaped stadium spans adopting the cable net structure in China are mostly concentrated on about 100m at present, and according to the relevant suggested values of the vector-span ratio of the cable net structure in the technical specification of cable structure (JGJ 257-2012): the sag of the bearing cable is 1/10-1/20 of span, the camber of the stabilizing cable is 1/15-1/30 of span, and the saddle cable net structure span ratio in China is mostly arranged in the structure range. The Zhejiang people gym built in 1968 is the first saddle-shaped single-layer cable net structure in China, the horizontal projection of the Zhejiang people gym is an 80m by 60m elliptical plane, the stable cable span ratio is 1/18, and the load bearing cable span ratio is 1/20; the Suzhou Olympic center natatorium built in 2018 is a saddle-shaped single-layer cable net structure with a span of 107m, the stable cable span ratio is 1/38, and the load-bearing cable span ratio is 1/15; the long axis span of the national speed skating hall to be built reaches 198m, the built national speed skating hall becomes a saddle-shaped cable net structure with the largest span in China, the vector-span ratio of the stabilizing cable is 1/28, and the vertical-span ratio of the bearing cable is 1/15.
Grid and latticework structures are also commonly applied to saddle-shaped large span structural roofs. The saddle-shaped latticed shell structure built at present mostly adopts a double-layer latticed shell or a single-layer and double-layer combined latticed shell: the Deyang gymnasium built in 1994 is the first saddle-shaped double-layer steel latticed shell structure in China, the horizontal projection is a diamond shape, a linear side beam is adopted, the span reaches 105m, the vector-span ratio in the stable direction is 1/7.28, and the vertical-span ratio in the bearing direction is 1/6; a saddle-shaped double-layer steel latticed shell roof is adopted in a Chinese petroleum university gym built in 2009, the horizontal projection is oval, the long axis span reaches 142m, the vector-span ratio in the stable direction is 1/6.8, and the vector-span ratio in the bearing direction is 1/13. The integrated gymnasium roof of the Chinese ocean university built in 2009 adopts a saddle-shaped grid structure.
The structural forms commonly used for saddle-shaped roof at present have various characteristics.
The most commonly used cable net structure is a flexible structure, the stress of the structure presents obvious geometric nonlinearity, and the cable net structure has reasonable geometric configuration and structural rigidity after reasonable prestress is applied to the cable, so that the cable net structure becomes a load-bearing structure. Therefore, morphological analysis is required to be carried out when the cable net structure is designed, the process is complex, and a designer needs to have certain mathematical theoretical background and engineering experience. The cable net structure has higher requirements on construction precision, construction errors caused by the processing precision of components and nodes in the construction process can cause deviation of the formed cable net shape and the cable prestress distribution from design values, and even influence on the bearing capacity of the formed cable net structure. Meanwhile, the cable net structure can have the problem of cable clamp slippage due to the fact that cable force difference exists between adjacent cable pieces in the construction process. The cable net structure can generate great tensile force on the edge component, a ring beam with high rigidity needs to be arranged on the boundary to resist the tensile force of the cable, and the requirements on the stress and rigidity of the edge component are high. The sag and the rise of the stabilizing cable of the stressed cable are strictly required by the cable net structure, the smaller the sag and the rise of the stabilizing cable of the stressed cable are, the larger the pretension of the cable required for structure forming is, the higher the requirement on the rigidity of the ring beam is, and the greater the difficulty in design and construction is, so that the cable net structure is not suitable for the flat saddle-shaped roof.
The latticed shell structure and the grid structure are used as common structural forms in a large-span building and have the characteristics of light dead weight, large span and the like. However, considering that the structural layer of the single-layer hyperbolic paraboloid latticed shell is thin, the structure is easy to be subjected to overall instability under the action of strong external force, JGJ7-2010 space grid technical specification recommends that the span of the single-layer hyperbolic paraboloid latticed shell is not more than 60m, the vector-span ratio of a single hyperbolic paraboloid shell is 1/2-1/4 of the span, namely the saddle-shaped roof with a small vector-span ratio is not suitable for adopting a single-layer latticed shell structure. The problem of poor stability of the single-layer reticulated shell is improved to a certain extent by the double-layer reticulated shell, but when the double-layer reticulated shell is used for the saddle-shaped roof, the reticulated shell is required to be ensured to have a certain thickness, and JGJ7-2010 space grid technical regulation suggests that the reticulated shell is 1/20-1/50 of short span in thickness, so that the indoor use space of the building is reduced to a certain extent. The net rack structure has high integral rigidity, but when the net rack structure is used for a hyperbolic paraboloid roof, the net rack structure and the double-layer reticulated shell structure have the problems of uneven grid division, multiple rod piece types and the like caused by irregular structural shapes, and the technical problems are brought to component manufacturing and structural construction.
The beam string structure is a prestress self-balancing structure, the structure form is simple, and the prestress is applied to the lower inhaul cable to generate the internal force and deformation opposite to those under the action of external load on the upper structure, so that the structure obtains better rigidity and stress performance; meanwhile, the beam string structure has the self-balancing characteristic, when the beam string structure is acted by external load, the stress of the structure is a closed loop, the requirement on the supporting condition is not high, and meanwhile, the beam string structure can span a larger span. But stretch a string beam structure and also be a wind sensitive structure, stretch a string beam structure under the effect of wind-suction, the lower part cable internal force reduces, for the condition of avoiding the cable to appear relaxing and withdraw from work, often need additionally to increase cable prestressing force. In addition, the beam string structure belongs to a plane stress system, and an out-of-plane support system is required to be arranged for ensuring the out-of-plane stability of the structure.
SUMMERY OF THE UTILITY MODEL
The utility model discloses a solve the technical problem that exists among the well-known technique and provide a saddle shape semi-rigid cable network structure that can be applicable to large-span venue building roof structure, this structure has good atress performance and higher atress efficiency to the construction degree of difficulty is low.
The utility model discloses a solve the technical scheme that technical problem that exists among the well-known technique took and be: the planar projection of the structure is any one of an ellipse, a circle and a rhombus.
The utility model discloses a solve the technical scheme that technical problem that exists among the well-known technique took and be: a saddle-shaped semi-rigid cable net structure comprises tension string beams arranged in the forward direction of a stress direction, tension string beams arranged in the reverse direction of a stable direction and a boundary ring beam, wherein upper chord rigid members of all the forward tension string beams form a saddle-shaped concave surface, upper chord cables of all the reverse tension string beams form a saddle-shaped convex surface, lower chord cables of all the forward tension string beams and lower chord rigid members of all the reverse tension string beams form a concave elliptic paraboloid, a supporting rod is shared by the forward tension string beams and the reverse tension string beams at the intersection, the upper end of the supporting rod is connected with the upper chord rigid member of the forward tension string beams through a two-way hinge I, the lower end of the supporting rod is connected with the lower chord rigid member of the reverse tension string beams through a two-way hinge II, the lower chord of the forward tension string beams is connected with the lower chord rigid member of the reverse tension string beams, and the upper chords of the reverse tension string beams are connected with the upper chord rigid members of the forward tension string beams, and the upper chord rigid member and the lower chord rigid member of the forward beam string and the upper chord cable and the lower chord rigid member of the reverse beam string are respectively connected with the boundary ring beam through a support.
The planar projection of the structure is any one of an ellipse, a circle and a rhombus.
The upper chord rigid member of the forward beam string, the lower chord rigid member of the reverse beam string and the stay bar are made of any one of a round steel pipe, a square steel pipe and H-shaped steel.
The upper chord stay of the forward beam string and the upper chord stay of the reverse beam string are made of any one of parallel steel wire bundles, steel strands and steel wire ropes.
The utility model has the advantages and positive effects that:
1) the saddle-shaped semi-rigid cable net structure formed by the forward and reverse bidirectional orthogonal arrangement of the beam string structure has good stress performance and higher stress efficiency. When the structure bears downward vertical load, the string beam, the upper rigid member, the lower stay cable and the stay bar are mainly loaded; when the structure is subjected to wind suction, the reverse beam string formed by the lower rigid member, the upper inhaul cable and the stay bar in the stable direction equivalently bears reverse load, and the condition that the lower cable of the common beam string is loose under the wind suction is avoided.
2) The geometric nonlinearity of the beam string structure is not significant, and the saddle-shaped semi-rigid cable net structure formed by positive and negative two-way orthogonal arrangement can determine reasonable prestress distribution through force finding analysis, so that the stress performance is improved, and the limitation that a single cable net structure completely depends on the reasonable prestress distribution to obtain structural rigidity is avoided.
3) After the saddle-shaped semi-rigid cable net structure formed by the forward and reverse two-way orthogonal arrangement of the beam string structure applies prestress to the stay cable, the internal force and displacement of the rigid member can be effectively controlled, and meanwhile, the two-way arrangement of the beam string structure supports each other from the outside, so that the out-of-plane instability of the structure can be effectively limited.
4) The saddle-shaped semi-rigid cable net structure formed by the forward and reverse bidirectional orthogonal arrangement of the beam string structure has stronger overall stability and can be used for saddle-shaped roofs with small rise span ratio and small sag.
5) The number of the rods required to be connected by each non-support node of the saddle-shaped semi-rigid cable net structure formed by the forward and reverse two-way orthogonal arrangement of the beam string structure is less than that of the grid structure, and the problem of large cable force difference of adjacent rods in the cable net structure does not exist, so that the design and installation of the nodes are facilitated.
6) The saddle-shaped semi-rigid cable net structure formed by the forward and reverse two-way orthogonal arrangement of the beam string structure forms a self-balancing structure system in two directions respectively, and cannot generate overlarge thrust or pull force on the support, so that the design of support nodes and a lower supporting structure is facilitated.
7) The saddle-shaped semi-rigid cable net structural rod piece formed by the forward and reverse two-way orthogonal arrangement of the beam string structure is arranged in a concise and orderly manner, the problems of uneven distribution of double-layer net shell structures and grid structure grids and various rod pieces are avoided, and the indoor attractiveness of the building is improved.
Drawings
Fig. 1 is a three-dimensional perspective axial view of the present invention;
FIG. 2 is an axial view of the upper member arrangement of the present invention;
FIG. 3 is a side view of the lower layer member arrangement of the present invention;
fig. 4 is a plan view of the present invention;
FIG. 5 is a schematic view of a single frame in the force-receiving direction of the present invention;
FIG. 6 is a schematic view of a single frame in a stable direction;
fig. 7 is a schematic view of a node on the stay bar of the present invention;
fig. 8 is a schematic view of a lower node of the stay bar of the present invention.
In the figure: 1 is an upper chord rigid member, 2 is a lower chord stay cable, 3 is an upper chord stay cable, 4 is a lower chord rigid member, 5 is a stay rod, 6 is an upper node, 7 is a lower node, 8 is an anchoring node, 9 is a boundary ring beam, 10 is a U-shaped cable clamp, 11-1 is a bidirectional hinge I, 11-2 is a bidirectional hinge II, L1 is a receiving hinge IForce direction span, L2 Steady direction span, s1For stabilizing the spacing of oppositely-tensioned string beams in the direction s2Spacing between beam strings, f, in the direction of the forceltThe sag f of the rigid member on the upper chord of the beam string is positively expanded in the stress directionllAnd the sag of the lower chord cable of the forward-tensioned chord beam in the stress direction is shown, fst is the rise of the upper chord cable of the reverse-tensioned chord beam in the stabilizing direction, and fsl is the sag of the lower chord rigid member of the reverse-tensioned chord beam in the stabilizing direction.
Detailed Description
For further understanding of the contents, features and effects of the present invention, the following embodiments are exemplified in conjunction with the accompanying drawings as follows:
referring to fig. 1 to 6, a saddle-shaped semi-rigid cable net structure includes a beam string disposed in a normal direction of a stress direction, a beam string disposed in a reverse direction of a stable direction, and a boundary ring beam 9.
The upper chord rigid members 1 of all the forward tensioned string beams form a saddle-shaped concave surface, the upper chord guys 3 of all the reverse tensioned string beams form a saddle-shaped convex surface, and the lower chord guys 2 of all the forward tensioned string beams and the lower chord rigid members 4 of all the reverse tensioned string beams form a concave elliptic paraboloid.
At the intersection, the forward beam string and the reverse beam string share one stay bar 5, the upper end of the stay bar 5 is connected with an upper chord rigid member 1 of the forward beam string through a two-way hinge I11-1, the lower end of the stay bar 5 is connected with a lower chord rigid member 4 of the reverse beam string through a two-way hinge II 11-2, a lower chord stay 2 of the forward beam string is connected with the lower chord rigid member 4 of the reverse beam string, and an upper chord stay 3 of the reverse beam string is connected with the upper chord rigid member 1 of the forward beam string.
The lower chord stay 2 of the forward beam can be fixed on the lower chord rigid member 4 of the reverse beam by a U-shaped cable clamp 10, or a cable passing hole is formed in the lower chord rigid member 4, so that the lower chord stay 2 of the forward beam passes through the cable passing hole to realize the connection between the lower chord stay 2 of the forward beam and the lower chord rigid member 4 of the reverse beam, please refer to fig. 7 and 8. Similarly, the connection between the upper chord guy cable 3 of the reverse beam string and the upper chord rigid member 1 of the forward beam string can also adopt the structure.
The upper chord rigid member 1 and the lower chord cable 2 of the forward beam string and the upper chord rigid member 3 and the lower chord rigid member 4 of the reverse beam string are respectively connected with the boundary ring beam 9 through a support.
The planar projection of the saddle-shaped semi-rigid cable net structure can be any one of an ellipse, a circle and a rhombus. The upper chord rigid member 1 of the forward beam string, the lower chord rigid member 4 of the reverse beam string and the stay bar 5 can be made of any one of a round steel pipe, a square steel pipe and H-shaped steel. The lower chord stay 2 of the forward beam string and the upper chord stay 3 of the reverse beam string can be made of any one of parallel steel wire bundles, steel strands and steel wire ropes.
The upper node 6 is the intersection point of the upper chord rigid member 1 in the stress direction, the upper chord stay cable 3 in the stabilizing direction and the stay bar 5. The lower node 7 is the intersection point of the lower chord stay cable 2 in the stress direction, the lower chord rigid member 4 in the stable direction and the stay bar 5.
The saddle-shaped semi-rigid cable network structure described above is described in detail below:
the saddle-shaped semi-rigid cable net structure is formed by orthogonal arrangement of the beam string structure in the positive and negative directions, and is formed by the beam string structure which is placed in the positive direction of the stress direction, the beam string structure which is placed in the inverted stable direction and the boundary ring beam 9. The string beams in the stress direction and the stable direction are orthogonally arranged, the upper string rigid members 1 in the stress direction form saddle-shaped concave surfaces, the upper string guys 3 in the stable direction form saddle-shaped convex surfaces, and the lower layer members of the string beams in the two directions form concave elliptic paraboloids, namely the lower string guys 2 in the stress direction and the lower string rigid members 4 in the stable direction are both arranged in a concave manner. The upper chord rigid member 1, the lower chord stay cable 2 and the stay bar 5 form a forward beam structure in the stress direction, and the lower chord stay cable 2 is prestressed, so that the whole structure can counteract the internal force and deformation when a part bears external force, and the structural performance is improved. The upper chord stay 3, the lower chord rigid member 4 and the stay bar 5 form a reverse beam string structure in the stable direction, and the structure can effectively resist the wind suction effect by stretching the upper chord stay 3, so that the problem that the lower stay fails under the wind suction effect of the common beam string structure is solved.
The upper chord rigid member 1 and the lower chord stay cable 2 in the stress direction, and the upper chord stay cable 3 and the lower chord rigid member 4 in the stabilizing direction are respectively connected with the support through anchoring nodes 8, the anchoring nodes 8 are arranged on the support, the support is arranged on a boundary ring beam 9, and the boundary ring beam 9 is supported on a lower main body structure.
The upper chord rigid member 1 and the lower chord rigid member 4 in the stable direction are bending members, the stay bars 5 are axial stress members, and the section design and the checking calculation are carried out according to the design standard of a steel structure (GB 500017-2017); the section of the lower chord stay rope 2 in the stress direction and the section of the upper chord stay rope 3 in the stable direction are designed and checked according to the technical specification of cable structures (JGJ 257-2012).
The rise height of two directions of the saddle-shaped semi-rigid cable net structure formed by the positive and negative two-way orthogonal arrangement of the beam string structure can be determined according to building appearance and roof elevation, and the cable net structure can be used for a large-span gymnasium building roof structure, the sag and rise height of the common cable net structure are limited, the requirement on the boundary is higher, the problem of complex prestress design and construction tensioning is solved, meanwhile, the defects that the integral stability of a single-layer net shell structure is weaker and cannot be used for a small-rise span ratio roof are overcome, the variety of rod pieces is great when the double-layer net shell and the net rack structure are used for the saddle-shaped roof are avoided, the construction difficulty is high, and the problem that a stay cable is likely to be loosened and withdrawn from work under the strong wind absorption.
Although the preferred embodiments of the present invention have been described with reference to the accompanying drawings, the present invention is not limited to the above-mentioned embodiments, which are only illustrative and not restrictive, and those skilled in the art can make many forms without departing from the spirit and scope of the present invention, which is within the scope of the present invention.