CN104060759B - A kind of truss string structure of built-in oblique guy rope - Google Patents

Abstract

The invention discloses a chord truss with built-in oblique cables, which includes an upper chord, a web, a node sleeve, a lower chord, and an oblique cable. The upper chord and the web are connected through welding, and the web The lower end of the lower chord cable is connected to the node casing, and the two ends of the lower chord cable are fixed on the support nodes at both ends after passing through each node casing. The diagonal stay cables are arranged symmetrically, and the lower ends of the diagonal stay cables are fixed on the support nodes Above, the upper end of the oblique stay cable is connected to the fixed node of the upper chord, which can be any one of the upper chord and the web within the span range of the string truss from one-fifth to one-third of the distance from the adjacent support node intersection. In the present invention, a prestressed system that can provide two-way resistance is composed of the lower string cable and the inclined cable, which can adapt to the wind suction load. The present invention also has the advantages of less steel consumption, simple structure, low manufacturing cost, good performance, and easy construction. .

Description

String truss with built-in inclined cables

technical field

The invention belongs to the string-tension truss in the technical field of large-span string-tension roof structures, and in particular relates to a string-tension truss in which oblique cables are arranged inside the body.

Background technique

The tension truss structure was first proposed by Professor M. Saitoh of Nihon University in 1986. This structure is a new type of hybrid roof system different from the traditional structure. The self-balancing hybrid structure composed of cables and intermediate compression struts is also a relatively successful long-span prestressed spatial structure in the development of hybrid structural systems.

The string truss structure is characterized by a simple system, clear force, and various structural forms, giving full play to the advantages of rigid and flexible materials, and it is simple and convenient to manufacture, transport, and construct, so it has been well applied. In recent years, the long-span stringed truss roof structures represented by Shanghai Pudong International Airport Terminal Building, Guangzhou International Convention and Exhibition Center, Harbin International Convention and Exhibition Center, Beijing Agricultural Exhibition Hall, and National Stadium have become my country's landmark buildings.

At present, researchers in this field generally believe that the stress mechanism of the tension truss structure is to apply prestress to the flexible cables of the lower chord to cause the back deflection of the upper chord truss members, so that the final deflection of the structure under load can be reduced. The upper chord truss composed of intermediate compression struts adopts arch beams or truss arches. Under the load, the horizontal thrust of the arch is borne by the lower chord flexible cables to reduce the horizontal thrust of the arch on the support and reduce the horizontal displacement of the sliding support. . The string truss structure can exert the strong tensile performance of high-strength cables, improve the mechanical performance of the overall structure, and make the compression-bending members and tensile members complement each other and work together to achieve self-balancing.

Although this string truss structure in the prior art has many advantages, there are still several relatively big problems: (1) the string truss structure is a kind of wind load sensitive structure, and for modern long-span buildings, generally With the string truss structure of the light roof system, in areas with large wind loads or typhoon areas, under the action of wind suction, the lower string cables may relax or be compressed and quit working, and the self-balancing system does not exist, and the safety degree loss, so it is often necessary to prepare the roof to ensure that the structure does not lose stability and safety under the action of wind suction, so the existing string truss structure is not suitable for the effect of wind suction; (2) the lower chord of the string truss in the prior art The cable ball is formed of cast steel, which requires special processing and is difficult to make into a standard part; (3) The lower part of the string tension truss in the prior art only has the cable ball, and the lower string node should have a device to control the left and right movement of the cable ball during tension, and it must To ensure that the cable ball produces upward displacement, the number of construction auxiliary equipment increases, and the construction is more difficult.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a chord truss with built-in oblique cables, which includes an upper chord 1, a web 2, a node sleeve 3 and a support node 6, and the webs 2 are connected end to end in sequence , its upper end is connected with the upper chord 1 by welding, its lower end is connected with the node casing 3, the support nodes 6 are respectively arranged under the two ends of the string tension truss, and the string tension truss It also includes a two-way anti-force prestressing system. The two-way anti-force prestressing system includes a lower string 4, an upper string fixed node 7 and an oblique stay cable 5, wherein the lower string 4 passes through each node casing 3 in sequence, and its two The ends are respectively fixed on the support nodes 6; the upper chord 1 is respectively provided with one upper chord fixed node 7 near the ends on both sides; It is connected with the two upper chord fixed nodes 7 to form an isosceles triangle.

Further, a fixed pulley 8 for supporting the lower string 4 is installed inside the node sleeve 3 , and the lower string 4 passes through the fixed pulley 8 .

Further, the node sleeve 3 is a spherical structure.

Further, the prestress value criterion of the lower chord cable 4 and the oblique stay cable 5 is: under the action of the load combination F= _Fprestress + _{Fdead load} +( _{Flive load-} Fwind _{suction load} )/2, The vertical deformation of the string truss structure is close to zero.

Further, the upper chord fixed node 7 is the intersection of the upper chord 1 and the web 2, and the distance between the intersection and the adjacent support node 6 is one-fifth to one-third of the chord truss A span distance of one.

Further, the upper chord 1 is in the shape of an inverted V, and the lower chord 4 is in the shape of a V.

Further, the web member 2 is symmetrical with respect to the center line of the string tension truss.

Beneficial effects of the present invention:

1. Performance comparison under wind suction load

The tension truss structure in the prior art requires back-up on the roof to ensure that the structure does not lose stability and safety under negative wind pressure. The burden on the structure is increased during the vertical live load; while the tensioned truss of the present invention is equipped with oblique stay cables, the main function of the oblique stay cables is to prevent excessive back deflection of the structure under the action of wind suction, thereby ensuring that the lower string stay cables In addition, when the structure is subjected to conventional vertical live loads, the oblique stay cables can also provide elastic support for the string truss. Stress system, under the normal vertical live load of the structure, the internal force of the lower string cable increases, providing elastic support for the web, and the internal force of the oblique cable decreases. In other words, the internal force increment of the oblique cable points to the At the upper end, this internal force increment is used to resist the vertically downward live load. The oblique stay cable is equivalent to providing elastic support for the string truss. The upper jacking force of the rod is reduced, and the internal force of the oblique stay cable is increased, which has a good restraint effect on the reverse deformation of the structure.

2. Node structure comparison

In the prior art, the lower chord balls of the string truss are formed of cast steel, which require special processing and are difficult to make into standard parts; while the fixed pulleys of the string truss of the present invention can be made into standard parts, which can be processed by general machinery factories, and the cost is relatively low. Low, simple and easy to construct.

3 Comparison of the difficulty of construction and installation:

The lower part of the string tension truss in the prior art only has cable balls, and the lower chord nodes should be equipped with devices to control the left and right movement of the cable balls during tension, and to ensure the upward displacement of the cable balls, the construction auxiliary equipment increases, and the construction is more difficult; The invented string truss lower string transmits force to the joint casing through the fixed pulley, and then transmits the upper jacking force to the web rod, the friction force is greatly reduced, so that the left and right swing of the lower joint is already small, and the freedom of the upper and lower joints is added. It has been constrained by the quadrangular conical web rod, and there is no need to add auxiliary devices to the lower string node when tensioning the lower string cable, thereby greatly reducing the construction cost.

Therefore, compared with the prior art, the present invention has the advantages of low steel consumption, low cost, good structural stability, and is suitable for wind suction loads.

Description of drawings

Fig. 1 is the structural representation of the string tension truss of a kind of body of the present invention that is provided with oblique stays;

Fig. 2 is a top view of a string tension truss with oblique stay cables arranged in the body of the present invention;

Fig. 3 is a structural schematic diagram of the intersecting connection between the web and the upper chord of the present invention;

Fig. 4 is the A-A sectional view of Fig. 1;

Fig. 5 is the B-B sectional view of Fig. 1;

Fig. 6 is the C-C sectional view of Fig. 1;

Fig. 7 is a schematic diagram of the structure of the lower chord node formed by connecting the web member and the node sleeve of the present invention;

Fig. 8 is a schematic diagram of a string truss roof adopting the present invention.

In the figure: 1-top chord; 2-web rod; 3-node bushing; 4-bottom chord;

detailed description

In order to make the purpose and technical solutions of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiments of the present invention. Apparently, the described embodiments are some, not all, embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Those skilled in the art can understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It should also be understood that terms such as those defined in commonly used dictionaries should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted in an idealized or overly formal sense unless defined as herein Explanation.

The meaning of "and/or" in the present invention means that each exists alone or both exist simultaneously.

The meanings of "inside and outside" in the present invention refer to that relative to the device itself, the direction pointing to the inside of the device is inward, and vice versa, it is not a specific limitation to the device mechanism of the present invention.

The meaning of "left and right" mentioned in the present invention means that when the reader is facing the drawings, the left side of the reader is the left, and the right side of the reader is the right, rather than a specific limitation to the device mechanism of the present invention .

The meaning of "connection" in the present invention may be a direct connection between components or an indirect connection between components through other components.

Fig. 1 is a schematic structural view of a chord truss with oblique cables arranged in the body of the present invention; Fig. 2 is a top view of a string truss with oblique cables arranged in the body of the present invention; Fig. 3 is a web bar and a truss of the present invention Structural schematic diagram of the intersecting connection of the upper chord; Fig. 4 is the A-A sectional view of Fig. 1; Fig. 5 is the B-B sectional view of Fig. 1; Fig. 6 is the C-C sectional view of Fig. 1; Fig. 7 is the web member and the node sleeve of the present invention Schematic diagram of the structure of the lower chord node formed by pipe connection; FIG. 8 is a schematic diagram of the string tension truss roof of the present invention.

As shown in Fig. 1, it is a schematic structural diagram of a string tension truss provided with oblique stay cables in the body of the present invention. The chord truss includes an upper chord 1, a web 2, a node casing 3, a lower chord 4, and an oblique stay cable 5. The upper chord 1 and the web 2 are connected through welding (see Fig. 3 ), and the lower end of the web 2 It is connected with the nodal casing 3 (see Fig. 7), the two ends of the lower chord cable 4 pass through each nodal casing 3 and are respectively fixed on the support nodes 6 at both ends, and the oblique stay cables 5 are arranged symmetrically (see Fig. The lower end of the stay cable 5 is fixed on the support node, and the upper end of the oblique stay cable 5 is connected to the fixed node 7 of the upper chord, which can be one-fifth to one-third of the distance from the adjacent support node 6. Any intersection point between the top chord 1 and the web 2 within the span of the truss.

As shown in Figure 7, the joint casing 3 is a spherical structure, and each joint casing 3 is equipped with a fixed pulley 8 for supporting the lower string 4, and the lower string 4 passes through the fixed pulley 8 (see Figure 5) .

The basic working principle of a string truss with oblique stay cables arranged in the body of the present invention is as follows: the lower string cables 4 and the oblique stay cables 5 have a common structure of "prestress + constant load + (live load - wind suction load)/2" Under the action, the vertical deformation of the structure is close to zero as the criterion to apply prestress, so that the structure can produce an appropriate amount of back deflection under the joint action of "prestress + constant load". The advantage of this criterion is that "prestress + constant load + live load" The total downward displacement of the structure under the joint action is roughly equal to the total upward displacement of the structure under the joint action of "prestress + constant load + wind suction load", which realizes the optimal allocation of resources and achieves the purpose of saving steel; Under the state of "load", the lower string cables 4 and the oblique stay cables 5 form a prestressed system that can provide two-way resistance. The internal force of the cable is reduced, in other words, the internal force increment of the oblique cable is directed to the upper end of the oblique cable. This internal force increment is used to resist the vertical downward live load. The oblique cable is equivalent to providing elastic support for the string truss , under the action of wind suction, the internal force of the lower string cable decreases, that is, the upper force of the original lower string cable on the web bar decreases, and the internal force of the oblique stay cable increases, which has a good restraint effect on the reverse deformation of the structure.

A string tension truss with oblique stay cables arranged inside the body of the present invention can form a space roof as shown in FIG. 8 .

The above is only the embodiment of the present invention, and its description is relatively specific and detailed, but it should not be construed as limiting the patent scope of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims (7)

1. the truss string structure of a built-in oblique guy rope, comprise upper chord (1), web member (2), node sleeve pipe (3) and support node (6), described web member (2) head and the tail connect in turn, its upper end is connected by welding to pass through mutually with described upper chord (1), its lower end is connected with described node sleeve pipe (3), described support node (6) is separately positioned on below the two ends of described truss string structure, it is characterized in that, described truss string structure also comprises two-way drag pre-stress system, described two-way drag pre-stress system comprises last quarter rope (4), stationary nodes of winding up (7) and oblique guy rope (5), wherein, described last quarter rope (4) is in turn through each node sleeve pipe (3), its two ends are separately fixed on described support node (6), described upper chord (1) respectively arranges stationary nodes (7) of winding up described on the position of both side ends, each described support node (6) is connected with stationary nodes (7) of winding up described in two by described oblique guy rope (5), composition isosceles triangle.

2. the truss string structure of a kind of built-in oblique guy rope according to claim 1, it is characterized in that, described node sleeve pipe (3) is built with one for supporting the fixed pulley (8) of described last quarter rope (4), and described last quarter rope (4) is through fixed pulley (8).

3. the truss string structure of a kind of built-in oblique guy rope according to claim 2, it is characterized in that, described node sleeve pipe (3) is ball shape structure.

4. the truss string structure of a kind of built-in oblique guy rope according to claim 3, is characterized in that, described last quarter rope (4) with the prestressing force value criterion of oblique guy rope (5) is: at Load Combination F=F _{prestressing force}+ F _{dead load}+ (F _{live load}-F _{wind inhales load}under the effect of)/2, the vertical deformation of described truss-string-structure is close to zero.

5. a kind of truss string structure of built-in oblique guy rope according to claim 3 or 4, it is characterized in that, the intersection point that described stationary nodes of winding up (7) is described upper chord (1) and web member (2), the distance between described intersection point and adjacent support node (6) is the span length of described truss string structure 1/1 to three/5th.

6. the truss string structure of a kind of built-in oblique guy rope according to claim 5, it is characterized in that, described upper chord (1) is inverted v-shaped, and described last quarter rope (4) is V-shaped.

7. the truss string structure of a kind of built-in oblique guy rope according to claim 6, is characterized in that, described web member (2) is symmetrical about the center line of described truss string structure.