JP2011102500A - Trussed string beam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce bending moment caused by bearing a vertical load to reduce the cross sections and mass of both chord members while improving the bending rigidity of a trussed string beam including upper chord members, a lower chord member and strut members laid between both chord members, as basic components. <P>SOLUTION: The trussed string beam 1 includes two upper chord members 2, 2 parallel in the width direction; one lower chord member 3 facing both upper chord members 2, 2; and a plurality of strut members 4 laid between the two upper chord members 2, 2 and the lower chord member 3 at spaces in the length direction of the upper chord members 2, 2 and lower chord member 3 to constitute a space truss. Tie members 5 are laid between the two upper chord members 2, and the length direction end of the lower chord member 3 is directly or indirectly connected to the length direction ends of the upper chord members 2, 2 to complete the trussed string beam 1 as a beam. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a truss tension string beam having an upper chord member, a lower chord member, and a bundle member constructed between both chord members as basic constituent elements.

  A truss-type string string beam (truss beam) in which upper chord material and lower chord material are connected by diagonal material (lattice material) or bundle material is arranged in multiple rows at intervals in the direction of the structure. Construct a roof frame. The tension string beam is stabilized in a state in which the tension is maintained by the tension material that is stretched in the span direction bearing the weight of the lower string material in the span direction due to its own weight.

  In the whole roof frame, the tension material stretched between both ends of the stringed beam resists the tension that acts on both ends of the stringed beam by its own weight (vertical load) and tries to increase the distance between both ends, and bears the tension. By doing so, the tension of the tendon and the self-weight (vertical load) of the truss beam are balanced (see Patent Document 1). The tension material may be pre-tensioned in order to cancel the tension due to the weight of the string string.

  However, even if the weight of the roof frame and the tension of the tension material are balanced when the roof frame is installed in the lower structure, the equilibrium state is lost when either the weight of the roof frame or the tension of the tension material is won. Since it is easy to break, the roof frame is likely to vibrate in the vertical direction (vertical direction). For this reason, in order to suppress the vibration of the roof frame, it is necessary to provide the truss beam itself with a rigidity that is not easily deformed by the tension of the tension member (see Patent Document 2). ).

  In Patent Document 2, the truss beams of the upper truss material, the lower chord material, and the diagonal truss constructed between the two chord materials are juxtaposed in the row direction, and the adjacent truss beams in the direction of the row line are connected to each other by a connecting material. This ensures the integrity in the column direction. For the tension introduced into the tension member stretched in the span direction, four bundle members 4 constituting a three-dimensional truss having a quadrangular pyramid shape are arranged under the peak portion (top portion) of the truss beam. Therefore, the rigidity in the vicinity of the truss beam crest is secured, and deformation of the truss beam crest in the span direction due to tension is prevented.

JP-A-61-78934 (Claim 1, FIGS. 1 to 3) JP-A-3-279536 (Claim 1, page 2, lower right column, line 7 to page 3, upper left column, line 3, FIGS. 2 to 4)

  In Patent Document 2, a bundle member 5 constituting a truss is also arranged at an intermediate portion between the truss beam crest and both ends in the span direction, but this truss is composed of only two bundle members 5 arranged in the direction of the beam. Since it is a configured flat truss and does not constitute a three-dimensional truss, it is not a means for ensuring the rigidity in the span direction in the vicinity of the arrangement position of the bundle 5.

  The bundle member 5 located at the intermediate portion in the span direction other than the peak portion passes through the lower end of the bundle member 4 at the truss beam peak portion, and is applied to the intermediate portion in the span direction in order to apply tension to the tension member stretched between the two end portions in the span direction. It is only placed and pushing down the tendon.

  From this, when the tension material moves relative to the truss beam in the span direction (displaces), it tries to fall over the truss beam and does not become a resistance element against bending deformation. There is no room to contribute to granting. Therefore, the bundle 5 (planar truss) does not function as a fulcrum for receiving a reaction force from the lower structure when the roof frame is supported by the lower structure.

  The truss beams are directly supported by the lower structure at the positions of the two kinds of bundles 4 and 5, and are supported at five points in appearance. Since it is not substantially supported by the lower structure at the position, the fulcrum in the span direction is the three-dimensional truss (bundle material 4) in the mountain portion on the tension material, and the three points of both ends and the center.

  Therefore, in the case of Patent Document 2, the reaction force when the truss beam bears its own weight and an overload (vertical load) is only received at the three points of the span direction both ends and the center part. A bending moment is generated, and the maximum value appears at an intermediate position between both ends and the center. Since a bending moment is generated in the middle part between the ends and the center of the truss beam, the truss beam itself must have sufficient bending strength to resist this bending moment. As a result, the cross-section of the structural member of the beam increases, resulting in an increase in mass.

  From the above background, the present invention improves the bending rigidity of the truss beam composed of the upper chord material and the lower chord material, reduces the bending moment due to bearing a vertical load, and can reduce the cross section and mass of the constituent material. A truss tension string beam is proposed.

The truss string beam according to the first aspect of the present invention includes two upper chord members arranged in parallel in the width direction, one lower chord member facing both upper chord members, and a distance in the length direction of the upper chord member and the lower chord member. Is provided between the two upper chord members and the lower chord member, and a plurality of bundle members constituting a three-dimensional truss,
A bridging member is laid between the two upper chord members, and the end portion in the length direction of the lower chord member is directly or indirectly connected to the end portion in the length direction of the upper chord member to complete the beam. Is a constituent requirement.

  The truss string beam is tensioned to the lower string material at least in use (the lower string material becomes a string string), so that it maintains its form as a “string string” and possesses the ability to maintain its own form. This means that the string string is completed as a beam. “At least” means that in addition to the case where tension is introduced as a result of the truss tension string beam bearing its own weight (vertical load), tension may be applied in advance (in advance). Since tension is applied to the lower chord material, a steel reinforced member such as a shape steel having a high resistance to tension, a steel material such as PC steel, and fiber reinforced plastic are used for the lower chord material.

  The fact that the end portion of the lower chord material in the length direction is directly connected to the end portion of the upper chord material in the length direction means, for example, that the end portions of the upper chord material arranged in parallel approach each other and are connected (joined). The end portion of the lower chord material is connected (joined) to (Fig. 1- (b)). Indirectly connected means that, for example, the end portion of the lower chord material is connected (joined) to the connecting material that is installed between the end portions of the upper chord material that are juxtaposed and connected (joined) to both sides (see FIG. 1- (a)).

  When the truss tension string beam is in use, the tension to the lower chord material is preliminarily applied (pre-tension) and is supported by the lower structure at both ends in the length direction (span direction) and bears its own weight (vertical load) When this occurs, the lower chord material tends to extend in the length direction by its own weight, and may be given naturally. In either case, the truss string beam will show the ability to bear the vertical load including its own weight and the ability to maintain the form that does not cause bending deformation when the vertical load is loaded, by introducing tension into the lower chord material in the state of use. .

  When the truss string beam bears a vertical load including its own weight, the truss string beam tries to expand in the direction in which the distance between both ends in the length direction increases on the lower end side of the truss string beam, and a tensile force acts on the lower string material. When a tensile force is applied to the lower chord material, the length of the upper chord material in the lengthwise direction tends to be pulled toward the inside (longitudinal center side) on the lower end side of the cross section. The vertical load and the tensile force applied to the lower chord material are offset, and the truss string beam retains the resistance against the vertical load.

  Truss string beams consist of two upper chord members that are parallel in the width direction, and one lower chord member that faces the lower side of both upper chord members when the truss string beam is installed. The two upper chord members are constructed between the upper chord members and are integrated (unified) by a connecting member connected to the upper chord members. Two upper chord members and one lower chord member are installed between the upper chord members and the lower chord member, and are integrated by a bundle member connected to both.

  Bundling materials are arranged in multiple locations at intervals in the length direction of the truss tension string beam, attached to each placement location, and a plurality of bundling materials are combined to form a three-dimensional truss between the upper chord material and the lower chord material It will be erected. One end (upper end) of the plurality of bundle members is connected to a connection (connection) point between the upper chord member and the connecting member, and the other end (lower end) is gathered and connected to the lower chord member.

  Since the connecting material is constructed so as to straddle between the two upper chord members, two bundle members are arranged in the width direction of the truss tension chord beam. Also, since the bundle members are attached to each arrangement place and combined so as to form a three-dimensional truss, a plurality of bundle members are arranged in the length direction of the truss tension string beam. A number of tie members are attached to each location of the bundle material, spaced apart in the length direction of the truss tension string beam, and multiple bundle materials are arranged in the width direction of the truss string beam × multiple pieces in the length direction. A three-dimensional truss will be constructed.

  For example, in the case where two connecting members are arranged at intervals in the length direction of the truss tension string beam at each arrangement position of a bundle member (three-dimensional truss), the three-dimensional truss has four bundles of 2 × 2. It will be composed of materials. In this case, two connecting members are attached to each forming position of the three-dimensional truss constituting the three-dimensional truss (arrangement position of the bundle material) and spaced in the longitudinal direction of the upper chord member between the upper chord members arranged in parallel. In addition to being installed, one end (upper end) of the bundle material is connected to the connection point between each connecting material and the upper chord material, and the other end (lower end) of the plurality of bundle materials is gathered and connected to the lower chord material, A solid truss is constituted by these four bundle members (claim 2).

  As shown in Fig. 1- (a), the end part of the truss string beam is connected to the upper chord material with the upper chord material in parallel, and the lower chord material is connected (connected) to the joint material. When the lower chord material is indirectly connected to the upper chord material, the upper chord members arranged in parallel are connected to each other toward the end side as shown in FIG. In some cases, the end portion of the lower chord material is connected (connected) to the connecting portion (the lower chord material is directly connected to the upper chord material). In either case, the end of the lower chord material is connected to the end of the upper chord material, so that the truss tension string beam is completed, and handling (transportation), lifting, and installation to the lower structure in the completed state are performed in units of the truss string beam. Is called.

  As a result of increasing the number of fulcrum points for vertical loads including its own weight, a set of bundles that make up a three-dimensional truss are arranged at multiple locations at intervals in the length direction of the truss string beam. Are distributed over the entire length of the truss chord beam, so that the maximum value of the bending moment generated between the fulcrums can be reduced as shown in FIGS.

  Fig. 6 shows a conventional stringed beam composed of a straight upper chord material and lower chord material, and a bundle material laid between the two chord members at an interval in the length direction, and the stringed beam has a vertical load (self-weight). Bending moment distribution when receiving In this tension string beam, six bundle members are arranged between the upper chord member and the lower chord member in a state where a three-dimensional truss is not formed, and is erected vertically on both chord members.

  As shown here, the bending moment generated in the upper chord material has maximum values at three locations in the center in the length direction (span direction) and the bundle material position near the end, and the bending moment at the bundle material position becomes the maximum value. I understand that There is a tendency for the maximum value per location to increase due to the small number of locations where the maximum value appears.

  On the other hand, the truss of the present invention shown in FIG. 5 is composed of straight upper chord material and lower chord material as in FIG. 6, and bundle members constituting a three-dimensional truss are arranged at six positions spaced in the length direction. In the stringed beam, it can be seen that the number of maximum values of the bending moment appears more than in the case of FIG. 6, and the maximum value of the bending moment is smaller than in the case of FIG.

  Specifically, in comparison with FIG. 6, the bending moment at the position of the bundle member near the end in the length direction where the maximum value of the bending moment appears in FIG. It is about 40% or less of half the maximum value of the bending moment appearing at the bundle material position near the direction end. In addition, the bending moment at the central portion of the truss string beam in FIG. 5 is about 2-3% of the bending moment at the same position in FIG.

  FIG. 4- (b) shows the distribution of the bending moment in the truss chord beam that curves upward as shown in FIG. 4 (a), but unlike the linear case shown in FIG. As a significant effect, it can be seen that the bending moment reduction effect appears.

  By reducing the maximum value of the bending moment generated in the length direction of the truss tension string beam, it is possible to reduce the cross section of the upper chord material and the lower chord material, which are the basic components of the truss string beam, and to reduce the mass of each. Thus, it becomes possible to reduce the weight of the entire truss string beam.

  In addition, since multiple pairs of bundle members that make up a three-dimensional truss are distributed in the longitudinal direction of the truss tension string beam, the resistance to bending moment increases, so the bending rigidity of the truss tension string beam increases and the bending moment increases. The effect of reducing bending deformation due to is also improved.

  A three-dimensional truss is composed of part of the upper chord that is divided in the length direction of the upper chord in addition to the connecting material that connects the upper chord in parallel with four or more bundle members. Therefore, the effect of improving the bending rigidity of the upper chord material itself can also be obtained.

  Specifically, a space in the length direction of the upper chord material is secured between the upper ends of a plurality of bundle members arranged at each formation position of the three-dimensional truss, so that the truss tension chord beam can be viewed in the width direction (from the side). When this occurs, a part of the upper chord member and the two bundle members form a triangle (truss) as shown in FIG. This triangle contributes to improving the bending rigidity of the truss tension string beam, because the two bundle members have a bending moment acting on the upper chord member due to the horizontal force in the span direction acting on the lower end of the bundle member.

  As a result of increasing the number of fulcrum points for vertical loads including its own weight, a set of bundles that make up a three-dimensional truss are arranged at multiple locations at intervals in the length direction of the truss string beam. However, the maximum value of the bending moment generated between the fulcrums can be reduced.

  By reducing the maximum value of the bending moment generated in the length direction of the truss tension string beam, it is possible to reduce the cross section of the upper chord material and the lower chord material, which are the basic components of the truss string beam, and to reduce the mass. The overall weight of the string string can be reduced.

(A) is the perspective view which showed the structural example of the truss tension string beam of this invention, (b) is the perspective view which showed the modification of the edge part part of the truss tension string beam shown to (a). FIG. 1A is a side view of FIG. 1A, and FIG. 1B is a plan view of FIG. It is an enlarged view of the formation position part of the solid truss in FIG. (A) is a side view showing the truss string beam shown in FIG. 1-a as a model, and (b) is a distribution of bending moment generated in the upper chord material when the truss string beam of (a) bears a vertical load. FIG. It is a bending moment diagram showing a bending moment distribution generated in the upper chord material when a straight truss string beam of the present invention in which the upper chord material and the lower chord material are not convexly curved upward bears a vertical load. It is a bending moment figure which showed the bending moment distribution which arises in the upper chord material when a linear conventional truss tension string beam bears a vertical load. (A) is the elevation which showed the example of the structure using the truss tension string beam of this invention, (b) is the top view which extracted the truss tension string beam part of (a). 7A is a sectional view taken along the line xx of FIG. 7B, FIG. 7B is a top view of FIG. 7A, a sectional view taken along the line zz, and FIG. 7C is a sectional view taken along the line yy of FIG. Sectional drawing, (d) is a perspective view showing the relationship between the lower joining plate and the lower chord material for joining the lower ends of the four bundle members.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  1- (a) and (b) show two upper chord members 2 and 2 arranged in parallel in the width direction, one lower chord member 3 facing both upper chord members 2 and 2, upper chord members 2, 2 and lower chord Two upper chord members are provided between the two upper chord members 2, 2 and the lower chord member 3 at intervals in the length direction of the member 3, and a plurality of bundle members 4 constituting a three-dimensional truss. A connecting member 5 is erected between two and two, and the end of the lower chord member 3 in the length direction is directly or indirectly connected to the end of the upper chord member 2 and 2 in the length direction to complete the beam. The example of a structure of the truss tension string beam 1 is shown.

  As shown in FIG. 1- (a), a plurality of “three-dimensional truss formation positions” are arranged at intervals in the length direction of the truss stringed beam 1, and a plurality of bundles 4 are formed in units of “three-dimensional truss formation positions”. Is placed. Between the upper chord members 2 and 2 of the “three-dimensional truss formation position”, at least two connecting members 5 and 5 are laid in the length direction of the truss tension string beam 1, and the upper chord member 2 is located at both ends of the connecting members 5 and 5. The upper end of the bundle member 4 is connected (connected) to the connection point between the three-dimensional truss and at least four bundle members 4.

  In FIG. 1- (a), when the H-shaped steel is used for the connecting material 5, the strong axis direction is directed to the vertical direction or the normal direction of the curve described later, which is formed entirely by the upper chord material 2. However, the connecting material 5 also serves to constrain the relative movement in the axial direction between the two upper chord members 2, 2 in parallel (to prevent displacement), so that the direction in which the relative movement occurs between the upper chord members 2, 2, Alternatively, it may be appropriate to orient the strong axis direction in the horizontal direction and the weak axis direction in the vertical direction or the like.

  As shown in FIGS. 1 to 3, a set of four or more bundle members 4 constituting the three-dimensional truss is arranged at a plurality of positions at intervals in the length direction of the truss tension string beam 1 (upper chord material 2). In the drawing, a case where three solid trusses having two connecting members 5 and 5 arranged in parallel in the length direction are arranged in six places in the length direction of the truss tension string 1 is shown. The number of three-dimensional trusses is arbitrary.

  The two upper chord members 2 and 2 are basically arranged in parallel with each other in a section including a plurality of three-dimensional truss formation positions formed of a plurality of bundle members 4. The connecting members 5, 5 parallel to each other in the length direction of 2 are installed between the upper chord members 2, 2 and connected to both. When the connecting members 5 and 5 are installed in parallel in units of “formation position of the three-dimensional truss”, the two upper chord members 2 and 2 are integrated (unified), and the interval is maintained over the entire length.

  The lower ends of the plurality of bundle members 4 arranged at the “formation position of the three-dimensional truss” are connected (coupled or joined) to the lower chord member 3 in a state of being gathered at one point. By connecting (connecting) the lower ends of the plurality of bundle members 4 to the lower chord member 3, the two upper chord members 2, 2 and the lower chord member 3 are integrated (unified), and the truss tension string beam 1 is configured. Is done.

  Two or more connecting members 5, 5 arranged in parallel in the length direction of the truss tension string beam 1 are arranged at the “formation position of the three-dimensional truss”, and are connected to connection points (connection points) between the connecting members 5 and the upper chord material 2. Since the upper ends of the bundle members 4 are connected (linked), the three-dimensional truss has at least four bundle members 4 and at least two connecting members 5 arranged in parallel in the length direction of the upper chord member 2 as shown in FIG. 5 and a part of the upper chord material 2, 2 defined by the two connecting members 5, 5, are formed in a quadrangular pyramid shape. The two upper chord members 2, 2 that are integrated (unified) in a plane composed of a part of the two connecting members 5, 5 and two upper chord members 2, 2 forming a quadrangle. A brace may be installed to ensure the property (shear rigidity).

  Since the bundle member 4 constitutes a three-dimensional truss, both ends thereof are pin-joined to the upper chord member 2 or the connecting portion of the upper chord member 2 and the connecting member 5 and the lower chord member 3, respectively. It is sufficient to connect (pin joint) between the material 2 and between the bundle material 4 and the lower chord material 3 so that a bending moment is not transmitted.

  The two upper chord members 2, 2 are linearly formed over the entire length as shown in FIG. 5, and are curved or bent upwardly as shown in FIGS. 1 and 2- (a). In some cases, the lower chord material 3 may be linearly formed over the entire length, or may be curved or bent upwardly as a whole.

  When the upper chord material 2 has a generally convex shape, the upper chord material 2 is uniformly curved, and at least two connecting members 5 installed at the formation position of the three-dimensional truss as shown in the figure. In some cases, an angle is given between the axes of the upper chord material 2 in the section divided by 5 and the other sections, resulting in a polygonal shape. When the angle of the axis of the upper chord member 2 is angled between the section of the three-dimensional truss divided by the two connecting members 5 and 5 and the other sections, the lower chord member 3 is similarly “the formation position of the three-dimensional truss”, that is, An angle is formed between the axes of the lower chord members 3 across the position of the point where the lower ends of the bundles 4 are connected.

  When there is an angle between the axis of the upper chord material 2 and the axis of the lower chord material 3 across the connection point with the bundle material 4, the upper chord material 2 and the lower chord material 3 are section units in which the respective angles are attached, that is, the bundle material 4 Although the upper chord material constituting material and the lower chord material constituting material are constructed between the upper end portions and the lower end portion units, they may be connected to the upper end portion and the lower end portion of the bundle material 4, but the upper chord material 2 and the lower chord material 3 are continuous. Although it is a single member, it may be formed in advance in a shape bent at the position of the bundle 4.

  FIG. 4- (a) shows that the upper chord member 2 is composed of a single member that is bent while being partially bent at the upper end position of the bundle member 4 (the position where the three-dimensional truss is formed), and the lower chord member 3 is the bundle member. 4 is divided into lower chord material constituting materials in units between lower end portions (three-dimensional truss formation positions), and the divided lower chord material constituting materials are installed between the lower end portions of the bundle material 4, and the end portions thereof are bundles of a plurality of bundles. The case where it pin-joins to the lower end part of the material 4 is shown.

  When the two upper chord members 2 and 2 are parallel to each other over the entire length as shown in FIGS. A material 5 is installed and connected to both sides. In this case, both ends in the length direction of the lower chord material 3 are connected (joined) to intermediate portions of the connecting members 5 and 5 that are spanned between both ends in the length direction of the upper chord material 2, 2, thereby lower string The material 3 is indirectly connected to the upper chord material 2. The lower chord member 3 is connected to the connecting members 5 and 5 so that the two upper chord members 2, 2 and one lower chord member 3 are closed, and the bending rigidity and torsional rigidity of the truss tension string beam 1 are ensured.

  The end portions in the length direction of the upper chord members 2 and 2 that are juxtaposed may be connected (joined) to each other as shown in FIG. 1- (b). In this case, the upper chord members 2, 2 are connected (joined) to each other by gradually approaching from the forming position of the solid truss located near the end of the truss tensioned string beam 1 to the end. The lower chord material 3 is directly connected to the upper chord material 2 by connecting (joining) the lower chord material 3 to the ends of the two upper chord materials 2 and 2 connected to each other. The two upper chord members 2, 2 and one lower chord member 3 are assembled and connected (joined) at one point, so that the end portion of the truss tension chord beam 1 is closed.

  FIG. 7 shows a construction example (use example) of the truss string string 1. As shown in FIG. 7, a plurality of truss string beams 1 are arranged in the width direction and connected to each other directly or via a horizontal member 10 erected in the direction of the row such as a purlin, thereby forming a roof structure as an upper structure. When formed and used, the structure is configured by being supported by the walls and girders of the lower structure 20 at both ends in the length direction (span direction).

  When the truss chord beam 1 is placed in a use state as shown in FIG. 7, when the upper chord member 2 bears a vertical load, the lower chord member 3 bears a tensile force, so that the entire truss chord beam 1 moves downward vertically. Restrains the drooping. When the truss string beam 1 receives a vertical load, the lower chord member 3 mainly bears a tensile force, and therefore, the lower chord member 3 is made of a material such as a steel material having resistance to the tensile force. Since the lower chord material 3 bears a tensile force at least in use, it functions as a string. In some cases, the lower chord member 3 is installed between both ends of the upper chord member 2 in a state in which tension is applied in advance.

  Since the upper chord material 2 receives a reaction force at both ends in the length direction and the position of the solid truss (a plurality of bundle members 4), it bears a compressive force and a tensile force (bending moment). A material such as a steel material having a resistance capability against the above, or a composite material of a steel material and others is used.

  Specific examples of joining the bundle material 4 with the upper chord material 2 and the lower chord material 3 are shown in FIGS. 8- (a) to (d). Here, the case where an H-shaped steel continuous in the length direction is used as the upper chord material 2 and two plates which are continuous in the length direction are used as the lower chord material 3 is shown, but the upper chord material 2 and the lower chord material 3 are shown. Each of the cross-sectional shapes in the case of using the shape steel is arbitrary, and can be freely determined in relation to the bundle 4 to be joined.

  The overall shape of the upper chord member 2 and the lower chord member 3 is curved so as to draw an upwardly convex curve from one side in the length direction (span direction) to the center side. 8A is a cross-sectional view taken along line xx of FIG. 7B, FIG. 8B is a top view of FIG. 7A (cross section taken along the line zz), and FIG. The side surface of the y-line is shown. (D) shows the relationship between the lower chord member 3 and the lower joining plate 7 for joining the lower ends of the four bundle members 4 to the lower chord member 3.

  The upper end portion of the bundle material 4 and the upper chord material 2 may be joined to such an extent that no bending moment is transmitted between them, and the joining method is arbitrary, but in FIG. The upper ends of the four bundle members 4 to be joined at different positions are cut in parallel to the surface of the lower flange of the upper chord member 2 and the upper joining plate 6 is welded to the end face. It is bolted or welded over the lower flange. One flat plate is used for the upper bonding plate 6.

  The joining method of the lower end of the bundle material 4 and the lower chord material 3 is arbitrary as long as the bending moment is not transmitted between the two, but in FIGS. A lower joining plate 7 is arranged in a plane and cross shape at the lower end position of the four bundle members 4 to be joined, and the upper surface of the gusset plate 9 of the lower chord member 3 is arranged at the lower end of the four lower joining plates 7. The receiving plate 8 is welded to the top. The lower surface of the receiving plate 8 is welded with a gusset plate 9 for being directly joined to the lower chord member 3 by bolt joining or welding. Although the receiving plate 8 is formed in a disc shape in FIG. 8, the planar shape of the receiving plate 8 is arbitrary.

  Since the four lower joining plates 7 are combined in a plane and cross shape at the lower end position of the four bundle members 4, the lower ends of the four bundle members 4 are parallel to the surface of the lower joining plate 7. It cut | disconnects and the cut surface is welded to both in the state which straddled two adjacent lower joining plates 7 and 7. FIG.

  FIG. 8 also shows (d) that the gusset plate 9 welded to the lower surface of the receiving plate 8 to which the lower end of the lower joining plate 7 is welded is joined to the gusset plate 9 with the lower chord material 3 sandwiched therebetween. Thus, the lower chord material 3 is composed of two plates as the lower chord material constituting material 31. As shown in FIG. 8, when the gusset plate 9 is joined to the lower surface of the lower joining plate 7 assembled in a cross shape via the receiving plate 8, the lower chord material constituting member 31 is an angle steel, a channel steel, a steel bar, etc. In FIG. 8, a plate is used as the lower chord material constituting material 31 in order to reduce the weight of the lower chord material 3.

  In the drawing, as described above, a three-dimensional truss comprising two connecting members 5 and 5 as a set is connected to two connecting members 5 and 5, and a total of four bundle members 4 connected to both ends of each connecting member 5. The two upper chord members 2 defined at both ends of the connecting members 5 and 5 are formed in a quadrangular pyramid shape. By forming a three-dimensional truss in the form of a quadrangular pyramid from two bundle members 4 and 4 arranged in parallel in the length direction and the width direction of the truss tension string beam 1 in units of “three-dimensional truss formation position”, the lower chord material 3 For the horizontal chord in the length direction of the lower chord member 3 acting on the lower end of the bundle member 4, the two bundle members 4, 4 juxtaposed in that direction exert a bending moment on the upper chord member 2, 2. Therefore, the three-dimensional truss functions to impart bending rigidity to the truss tension string beam 1.

  For the horizontal load in the width direction of the lower chord 3 acting on the lower end of the bundle 4 from the lower chord 3, the two bundles 4, 4 juxtaposed in the direction twist to the upper chords 2, 2. In order to apply a moment, the three-dimensional truss functions to impart torsional rigidity to the truss tension string beam 1.

  FIG. 7 shows an example in which a combination of a plurality of trussed string beams 1 is used as a roof frame covering a large space such as a gymnasium. The roof frame is constructed by laying a horizontal member 10 such as a purlin member at the position of the upper chord member 2 between a plurality of truss string members 1 and 1 arranged in parallel in the direction of the beam and connecting the truss string members 1 and 1 to each other by the horizontal member 10. Composed. As shown in FIG. 8, a roofing material 11 such as a deck plate is laid on the upper chord material 2 of the plurality of trussed string beams 1 to constitute a roof frame. Although not shown, in some cases, a lower connecting material parallel to the horizontal material 10 is installed at the position of the lower chord material 3, and the truss tension string beams 1 and 1 may be connected also by the lower connecting material.

  In order to ensure the horizontal rigidity (in-plane rigidity) of the roof frame between the truss tension string beams 1 and 1 arranged in parallel in the width direction, a horizontal brace 12 is installed as shown in FIG. The truss tension string beams 1 and 1 are also connected to each other.

1 ... Truss string beam,
2 ... Upper chord material, 3 ... Lower chord material, 31 ... Lower chord material component,
4 ... Bundles, 5 ... Binders,
6 ... Upper joining plate, 7 ... Lower joining plate,
8 ... receiving plate, 9 ... gusset plate,
10 …… Horizontal material,
11 …… Roofing material,
12 …… Horizontal brace,
20: Substructure.

Claims (2)

Two upper chord members arranged in parallel in the width direction, one lower chord member facing both upper chord members, and the two upper chord members and the lower chord spaced apart in the length direction of the upper chord member and the lower chord member A plurality of bundles that are erected between the materials and constitute a three-dimensional truss,
A bridging member is laid between the two upper chord members, and the end portion in the length direction of the lower chord member is directly or indirectly connected to the end portion in the length direction of the upper chord member to complete the beam. Truss string beam, which is characterized by Two connecting members are installed between the upper chord members arranged in parallel at the respective formation positions of the three-dimensional truss and spaced in the longitudinal direction of the upper chord member, and each connecting member and the upper chord member One end of the bundle material is connected to the connection point, and the other ends of the plurality of bundle materials are gathered and connected to the lower chord material, and a solid truss is constituted by the four bundle materials. The truss tension string beam according to claim 1.

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