JPH03279536A - Stretched chord beam process for large span constructed frame body - Google Patents

Abstract

PURPOSE:To make the introduction of prestress without deforming the central part of the ridge of a roof by spanning a stretching member between the lower end of a space truss formed on the central part of the ridge and bearing parts on both the ends of the ridge in a large span constructed frame body, and stretching the above member. CONSTITUTION:Many single members are assembled, and an upper and a lower chord member 2..., 3... are arranged in a nearly doglegged shape centering around the ridge of a roof to form a large span constructed frame body 1. Bearing parts on both ends of the constructed frame body 1 are fixed on lower constructing bodies 10, 10 so as to be laterally movable in the direction of the span. Plural bundle materials 4 are hung down from the central part of the ridge to form plural inverse square pyramid-shaped space trusses (a), whose lower end parts are continuously connected through tying materials 8, 8 in a ridge direction. Stretching members 23, 23 are continuously spanned between the bearing parts on both the ends of the frame body and the lower ends of the space trusses (a), and stretched to introduce prestress in the direction of the span into the constructed frame body 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a strung beam construction method comprising a combination of a truss beam and tendons.

[Conventional technology]

In recent years, the string beam construction method, which is suitable for large span bridges and involves passing tension members along the span direction of parallel chord truss, chevron truss, or arch truss, and introducing prestress to the entire truss by pulling the tension members, has been attracting attention. .

According to this type of construction method, part of the load can be borne by the tendons, so the stress in the lower chord member can be significantly reduced, and the cross section and beam size of the lower chord member can therefore be significantly reduced. At the same time, it is also possible to easily correct the deflection at the center of the beam that is unavoidable in large-span structures.

By the way, in the conventional tensioned beam construction method, since the beams are all straight in plan view, prestressing can be introduced relatively easily.

[Problem to be solved by the invention]

However, recently, large-span buildings with novel shapes, such as those seen at expositions, have been frequently constructed.

For this reason, truss beams with various shapes, not just mountain-shaped or arch-shaped, are now being used.

For example, like the truss beam of the present application, a truss beam may be used that has a mountain shape and has an upper chord member and a lower chord member arranged in a “<” shape in the span direction when viewed from above.

Even if an attempt was made to introduce prestress into such a truss beam in the span direction using the conventional strung beam construction method, the ridge of the truss would be deformed, making it impossible to construct a strung beam.

This invention was proposed in view of these circumstances.
The purpose of the present invention is to provide a strung beam construction method that can introduce press stress even into a large span frame in which the upper chord members and lower chord members are arranged in the shape of a "<" when viewed from above in the span direction. be.

[Means to solve problems]

This invention arranges many single members in a three-dimensional and systematic manner, and when the upper and lower chord members of the single members are viewed planarly, approximately “<” is formed in the span direction centering on the ridge. This relates to a tensioned beam construction method for large-span bridge structures that introduces prestress in the span direction to a large-span frame structure constructed by arranging the structure in a shape of a bend. The support part is fixed on top of the lower structure so that it can be moved laterally in the span direction, and a plurality of bundles are suspended in the center of the ridge of the large span frame structure, and the bundles are used to move the center of the ridge. A plurality of three-dimensional trusses in the shape of an inverted quadrangular pyramid are constructed on the lower side at regular intervals in the column direction, and the lower ends of the three-dimensional trusses are continuously connected in the column direction by a plurality of connecting members, and both ends are connected continuously in the column direction. By continuously spanning the tension material between the support part and the lower end of the three-dimensional truss, tensioning the tension material, and fixing both ends and the intermediate part to the left and right ends of the support part and the lower end of the three-dimensional truss, respectively. The above objective is achieved by introducing prestress into the large span crosslinked body in the span direction.

〔Example〕

The present invention will be described below based on an illustrated embodiment.

The large span frame structure 1 is constructed by three-dimensionally and systematically arranging many single members made of steel pipes, etc., and the entire bridge constitutes a three-dimensional truss structure.

Further, the large-span bridge 1 has a protruding shape with a ridge at the center when viewed from the side.

Also, among the many single members that make up the large-span bridge structure 1, the top chord member 2 at the center of the structure. ...and lower chord material 3. are arranged continuously in a substantially straight line in the span direction when viewed from above,
From this, upper chord members 2, ... and lower chord members 3 on both sides. ...
are arranged continuously in a substantially ``<'' shape in the span direction around the ridge.

A plurality of bundle members 4, 4 are hung below the central part of the ridge of the large span frame structure 1, and bundles 4, 4 are installed below the approximately intermediate part between the central part of the ridge and the supporting parts at both ends. Each material 5.5 is vertically installed.

The bundle members 4 and 5 are suspended from the respective contact points of the lower chord member 3 and the diagonal member 6, and the lower ends of the bundle members 4 and 4 are connected to each other by a ball joint 7, and as a result, Under the central part of the ridge, three-dimensional trusses a each having an inverted quadrangular pyramid shape and consisting of four bundle members 4 are arranged at regular intervals in the longitudinal direction of the large span frame structure 1.

Further, the lower end portions of each three-dimensional truss a, . . . are connected continuously in the column direction by connecting ball joints 7°7 with connecting members 8, respectively.

Therefore, since the ridge of the large span frame structure 1 constitutes a rigid contact point, it will not deform at all even if prestress is introduced in the span direction.

Supports 9, 9 are installed at the support portions at both left and right ends of the large span frame structure 1.
are installed at regular intervals in the column direction.

The large-span bridge body 1 configured in this manner is bridged over and fixed to a lower structure 10.10 such as a column or a beam.

A base metal fitting 11 is installed at the upper end of the lower structure 10.10, and the supports 9.9 at both ends of the large span frame structure 1 are installed and fixed on the base metal fitting 11, respectively.

Note that sliding members 12 and 12 made of Teflon or the like are interposed between the support body 9 and the base metal fitting 11, so that the support body 9 can be easily moved laterally before being fixed.

The base metal fitting 1 is constructed by protruding a plurality of legs 14, 14 from the underside of the base plate 13.

The base plate 13 is formed into a rectangular plate shape of a predetermined size, and a plurality of joining holes 15, 15 are bored in the center and peripheral parts.

The joining holes 15.15 are formed in the shape of elongated holes in the span direction of the large span bridge 1.

The legs 14.14 are formed in a substantially groove-like cross section that opens directly upward;
It is integrally welded and fixed substantially parallel to the lower side of the base plate 13.

The base metal fitting 11 configured in this way is a lower structure lO.
Only the legs 14 and 14 are buried in concrete, and the base plate 13 is placed between the upper end of the lower structure and the road surface.

The bottom of the leg 14.14 is connected to a plurality of anchor bolts 16 embedded in the concrete of the lower structure 10 in advance.
are integrally fixed by a plurality of fixing nuts 17.17.

The support 9 has a plurality of vertical plates 19.19 welded and fixed on the horizontal plate 18, and the vertical plates 19.1
It is constructed by welding and fixing the ball joint 7 on top of the ball joint 9.

A plurality of bonding holes 21.21 are provided approximately at the center and around the periphery of the horizontal plate 18, and are connected to bonding holes 15.15 of the base plate 13.
Corresponding to the above, the hole is formed in the shape of an elongated long hole in the span direction of the large span bridge 1.

Joint bolts 22 are fastened to the corresponding joint holes 15 and 17, and the support body 9 is fixed onto the base metal fitting 11 by the plurality of joint bolts 22.

With this configuration, the left and right support bodies 9, 9 are fixed on the base metal fittings 11.11, so that when the large span frame structure 1 is fixed to the lower structure 1010, the large span frame structure 1 is fixed to the lower structure 1010. Its position can be adjusted by appropriately moving it in the span direction.

In such a case, since both the joining holes 15 and 17 are long holes, the large span cross-linked body 1 can be moved largely relative to the diameters of the joint holes 15 and 17, and the large span cross-linked body l
It is possible to correct large positional deviations.

Tensile members 23 made of PC steel wire or the like are stretched along the span direction between the left and right supports 9, 9 of the large span frame structure 1, the bundle members 5, and the ball joint 7 at the lower end of the three-dimensional truss a.

The middle part of the tension material 23 is tensioned and fixed to the fixing hole 24 of the ball joint 7 at the lower end of the bundle material 5 and the three-dimensional truss a by the fixing fitting 20, and the left and right end parts are fixed to the fixing hole 24 of the ball joint 7 of the left and right supports 9, 9. 24 with a fixing metal fitting 20.

Before the tension material 23 is fixed at both ends, it is pulled from both ends by a hydraulic jack or the like, thereby introducing a predetermined amount of prestress into the large span frame structure 1 in the span direction.

The tension members 23 are installed at regular intervals in the longitudinal direction of the large span frame structure 1.

In such a configuration, a method of introducing prestress into the large span frame structure l will be explained.

The left and right supports 9, 9 of the large span frame structure 1 are attached to the base metal fittings 11.
．． 11, the tension members 23 are pulled from both ends with a hydraulic jack or the like to introduce a prestress of a predetermined amount into the large span frame structure l in its span direction.

Subsequently, both ends of the tension material 23 are fixed in the fixing holes 24 of the ball joint 7 of the support body 9 by the fixing fittings 20.

Further, the intermediate portion of the tension material 23 is also fixed in the fixing hole 24 of the bundle material 5 and the ball joint 7 at the lower end of the three-dimensional truss by a fixing metal fitting.

Subsequently, the left and right supports 9.9 are positioned on the base metal fitting 1111 and then integrally fixed.

In addition, if we decide to fix the left and right supports 9, 9 after introducing prestress to the large span frame structure 1, the central part of the ridge will rise slightly when prestress is introduced to the large span frame structure 1, and as a result, This is to absorb the position of the support bodies 9.9 at both left and right ends, which shift inward.

〔Effect of the invention〕

Since the present invention has the above configuration, it has the following effects.

■ Multiple bundles are hung vertically at the center of the ridge, and these multiple bundles form a three-dimensional truss in the shape of an inverted quadrangular pyramid at regular intervals in the direction of the girder at the bottom of the center of the ridge. In addition, since the lower ends of the three-dimensional truss are continuously connected in the girder direction by connecting materials, the central part of the ridge forms a rigid contact point,
Even if prestress is introduced in the span direction, the central part of the ridge will not deform.

Therefore, even if the upper and lower chord members of a large-span frame structure are bent in the span direction with the ridge at the center when viewed from above, the tension members will Prestressing can be introduced in the span direction of the frame.

In addition, since the upper chord member and the lower chord member are arranged in a substantially “<” shape in the span direction with the ridge as the center when viewed from above, prestress can be introduced in the span direction. Therefore, prestress can be introduced in the column direction at the same time.

■ In addition, since the supports at both left and right ends of the large-span bridge are fixed on the base metal fittings of the lower structure so that they can move in the span direction, it is possible to It can easily absorb misalignment and misalignment of the support part during construction and reliably fix it in a predetermined position.

[Brief explanation of drawings]

Figures 1 to 8 show embodiments of the present invention; therefore, Figure 1 is a partial plan view of the large span frame structure, Figure 2 is a schematic perspective view thereof, and Figure 3 is similar to Figure 2. Fig. 4 is an enlarged view of part A in Fig. 2, Fig. 5 is an enlarged side view of the left and right end support portions of the large span frame structure, Fig. 6 is a longitudinal sectional view thereof,
FIG. 7 is a plan view thereof, and FIG. 8 is an enlarged view of section C in FIG. 2. DESCRIPTION OF SYMBOLS 1... Large span frame structure, 2... Upper chord member, 3... Lower chord member, 4, 5... Bundle member, 6... Diagonal member, 7... Ball joint, 8... Connecting material, 9... Supporting body, 10... Lower structure, 11... Base metal fitting, 12... Sliding member,
13...Base plate, 14...Legs, 15...
Joining hole, 16...Anchor bolt, 17...Fixing nut, 18...Horizontal plate, 19...Vertical plate, 20...Fixing metal fitting, 21...Joining hole, 22...
・Joining bolt, 23...Tension material, 24...Fixing hole. Figure 1 Figure

Claims (1)

[Claims] (1) A large number of single members are arranged three-dimensionally and systematically, and when the upper and lower chord members of the single members are viewed planarly, approximately ``ku'' is placed in the span direction centering on the ridge. This is a tensioned beam construction method for large-span frames that introduces prestress in the span direction to a large-span frame that is constructed by arranging it in a bent shape, and the support at both ends of the large-span frame The lower structure is fixed so that it can move laterally in the span direction, and multiple bundles are hung vertically at the center of the ridge of the large-span frame structure, and the bundles extend under the center of the ridge. A plurality of three-dimensional trusses each having an inverted quadrangular pyramid shape are constructed at regular intervals in the girder direction, and the lower ends of the three-dimensional trusses are continuously connected in the girder direction by a plurality of connecting members, and both ends are supported. By continuously spanning the tension material between the section and the lower end of the three-dimensional truss, tensioning the tension material, and fixing both ends and the middle part to the supporting parts at both left and right ends and the lower end of the three-dimensional truss, a large A tensioned beam construction method for large span frame structures, which is characterized by introducing prestress into the span structure in the span direction.