JPH059910A - Pc complex truss structure and construction method - Google Patents

Abstract

PURPOSE:To effectively reinforce a structure due to prestress and also provide a very economical PC complex truss structure. CONSTITUTION:A PC truss structure type frame comprises upper and lower PC structured floor plates 3 and 4 and a truss structured web 5. Each of the upper and lower floor plates 3 and 4 and the truss structured web 5 are divided into a plurality of units, and each unit is assembled to the length of a construction block introducing prestress. These construction blocks are installed introducing prestress in order.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a PC composite truss structure applied to bridges and the like and a construction method thereof.

[0002]

2. Description of the Related Art Generally, in a prestressed concrete structure (hereinafter referred to as a PC structure) in which a cross-section force is alternating, such as an extrusion method or a cantilever construction, PC steel materials are arranged on both the upper floor plate and the lower floor plate. It is common to deal with cross-section force.

Although this reinforcing method is a rational method, since the compressive stress due to the prestress is added to the compressive stress due to the bending moment during the installation, in a general PC girder,
It is designed to increase the girder height to reduce the stress due to bending moment, but there is a problem that the main girder weight increases.

Therefore, recently, various studies have been made on the use of high-strength concrete and a method for reducing the weight by a composite structure, but there are various problems as described below for practical use.

Among these, the member size of the web in the conventional PC box girder structure is not determined by the shear strength, etc., but is determined by the arrangement intervals of the PC steel materials and the space for inserting the vibrator at the time of concrete placing. It is generally determined by structural details (see Figures 19 and 20).

Therefore, even if a high-strength concrete having the conventional cross-sectional shape as described above is used, the weight cannot be reduced to the minimum dimension or less in terms of structural details, and thus there is a limit to weight reduction.

As a method for reducing the weight of the PC structure, FIG.
A composite structure with a steel web structure as shown in Fig. 3 has been developed.However, in this structure, a part of the prestress introduced due to the high axial rigidity of the web is constrained by the web and cannot be used effectively. There are challenges. In particular,
When a high-strength concrete is used, the amount of prestress to be introduced tends to increase and the creep coefficient tends to increase, so that not only the loss of prestress due to the restraining force of the web increases but also it is transmitted to the web. Introduced force (loss of press tray) adversely affects unnecessary compression force.

Further, due to the creep and drying shrinkage of the concrete, a large shear shear force is generated at the joint between the steel and the concrete, and when a high strength concrete is used, the shear strength is further increased and not only the concrete is increased. -Experiments have shown that an increase in shear shear force cannot be expected even if the strength of the joint is increased, and it becomes difficult to reinforce the joint structure (gibel structure).

The present invention has been proposed in order to solve the above-mentioned problems of the prior art, and is a lightweight and extremely economical PC composite truss structure that can be effectively reinforced by prestressing. The purpose is to provide a construction method.

[0010]

In order to solve the above-mentioned problems, a PC composite truss structure and a construction method therefor according to the present invention are constructed as follows.

The PS composite truss structure according to the present invention is
It is constructed from upper and lower floor plates of a PC structure and a web of truss structure installed between the upper and lower floor plates, and the web is constructed as a steel structure or a PC structure.

In the construction method, the upper and lower floor plates of the PC structure and the web of the truss structure are divided into a plurality of units so as not to generate static constant force by the introduction of prestress, and each unit is prestressed. As it is being introduced, it is assembled to the length of the construction block, and this construction block is successively erected while introducing prestress.

It is also possible to construct the upper and lower floor plates of the PC structure over the entire length thereof, and to introduce prestress over the entire length thereof, and subsequently construct a truss structure web between the upper and lower floor plates.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an illustrated embodiment. In FIG. 1, reference numeral 1 is a main girder such as a bridge girder constructed by a PC composite truss structure according to the present invention. Is a plurality of main girder units 2 (hereinafter simply referred to as unit 2) in the span direction of the main girder 1,
It is constructed by joining together and introducing a predetermined amount of prestress over its entire length.

Each unit 2 is constructed from upper and lower floor boards 3 and 4 and a web 5, and the upper and lower floor boards 3 and 4 are formed in a rectangular plate shape from a reinforcing bar concrete using a high strength concrete, and are made of concrete. The main girder 1 is multiple PC steel materials 6
Are inserted along the span direction (see FIG. 2).

The PC steel material 6 is inserted in consideration of the number and the position of the PC steel material 6 so as to substantially match the centroid of the cross section of the main girder in order to minimize the static indeterminate force generated by the creep after completion of the main girder. ing.

Further, the PC steel materials 6 are respectively inserted into the concrete in a tensioned state, whereby the upper and lower floor boards 3,
A predetermined amount of prestress is introduced in each of the four.
Further, the PC steel materials 6 and 6 of the adjacent units 2 and 2 are connected by a coupler 7 in a tensioned state (see FIG. 4). Therefore, the upper and lower floor plates of each unit 2,2
Not only are prestresses introduced individually in 3, 4 but also prestress is introduced over the entire length of the main girder.

The web 5 is composed of a vertical member 8 installed on the left and right edges of the upper and lower floor plates 3 and 4 in the width direction, and diagonal members 9 and 9 installed on both sides of the vertical member 8. If necessary, it is constructed from brace members 10,10 which are erected in an X shape between the right and left vertical members 8,8 along the width direction of the upper and lower floor plates 3,4.

The vertical member 8, diagonal member 9 and brace member 10 are
Both are constructed in a rectangular cross section from a reinforcing bar concrete using high strength concrete like the upper and lower floor boards 3 and 4.
In addition, a plurality of PC steel materials 11 are respectively inserted into the concrete of each member in a tensioned state, whereby a predetermined amount of prestress is also introduced into the vertical material 8, the diagonal material 9 and the brace material 10. .

Further, the vertical member 8, the diagonal member 9 and the brace member
Both end portions of 10 are integrally joined to the edge portions of the upper and lower floor boards 3 and 4, and the diagonal members 9 and 9 of the adjacent units 2 and 2 are also joined by a plurality of joining bolts or joining pins 12 and 12, respectively. They are joined (see FIG. 5).

Therefore, the entire main girder 1 is constructed as a truss structure which is structurally extremely advantageous in the span direction and the width direction, and is also constructed as a PS structure using a high strength concrete.

The vertical member 8, the diagonal member 9 and the brace member 10 of the web 5 do not necessarily have to have a reinforced concrete structure but may have a steel structure.

FIGS. 6 and 7 show another embodiment of the unit 2, which is mainly used when the main girder 1 has a relatively small span and the web 5 does not require a large bending rigidity. It is applied.

The details will be described. The web 5 of the unit 2 is divided into upper and lower parts, and the upper and lower parts thereof are respectively made of vertical members on the left and right edges of the upper and lower floor plates 3 and 4 in the width direction. 7 and 2 instead of erection members 8 are constructed by arranging two or more V-shaped web members 13, 13 in parallel (in the embodiment, two V-shaped member members are installed). ).

In the unit 2, the upper and lower V-shaped web members 13, 13 of the web 5 are joined by a plurality of joining bolts or joining pins 12, 12, respectively, and the upper and lower floor plates 3, 4 are joined.
An X-shaped brace material (not shown) is installed between the two in the width direction. Other configurations are
It is almost the same as the unit described above.

As a general rule, the V-shaped web material 13 is H
Although it is composed of steel aggregate such as shaped steel, it is made of high-strength concrete.
In some cases, it may be composed of a PC or a PC concrete (see FIG. 7).

Next, the construction method will be explained step by step.

First, the unit 2 is assembled on the ground, and the units 2 and 2 are connected to each other with a length that can be carried by a crane or the like (see FIG. 3, hereinafter referred to as a construction unit).

To join the units 2 into a construction unit, the end portions of the upper floor plates 3 and 3 of the adjacent units 2, 2 and the end portions of the lower floor plates 4 and 4 and the end portions of the diagonal members 9 and 9 are adjacent to each other. Match each. And P of the upper floor board 3 and the lower floor board 4
C steel materials 6 and 6 are connected by a coupler 7, respectively.
At this time, the prestress is introduced into the connecting portion of the PC steel materials 6 and 6 by tightening the coupler 7 and pulling the PC steel materials 6 and 6 together rather than simply connecting them. The prestress in this case has the same magnitude as the prestress introduced into the PC steel material 6 in the concrete of the upper and lower floor plates 3 and 4.

Further, the diagonal members 9 and 9 are joined by a plurality of joining bolts or joining pins 12 and 12 (see FIG. 5).

Subsequently, an assembly of the units 2 assembled into a predetermined length, that is, the construction unit is referred to as a pier 1
The construction units are joined and bridged by the most suitable construction method between 4,14. The joining of the construction units in such a case is exactly the same as the joining method of the units 2 and 2 described above, and the PC steel materials 6 and 6 of the upper and lower floor boards 3 and 4 are connected by the coupler 7 and the PC steel materials are joined together. Introduced prestress to the connecting part of 6,6
And 9 are multiple multiple bolts or pins 1
Join with 2,12 (see Figures 4,5). Note that Fig. 18 shows a crane erection method using a vent-type support work.

As described above, the prestressing is not applied to the upper and lower floor boards 3 and 4 of the main girder 1 at once over the entire length of the main girder 1, but to the upper and lower floor boards 3 and 4 of the unit 2 individually. , Then, by introducing prestress to the connecting part of the upper and lower floor boards 3 and 4 of the adjacent units 2 and 2, it is possible to prevent the prestress from being restrained by the rigid web. It is possible to effectively utilize approximately 100% of the prestress.

Next, a PS composite truss structure according to another invention will be described with reference to an embodiment (FIGS. 8, 9, 10, 1).
1).

In the figure, reference numeral 15 is P according to the present invention.
Main girder such as bridge girder constructed by S composite truss structure. Main girder 15 connects a plurality of upper and lower floor boards 16 and 17 in the span direction of main girder 15 and introduces prestress over the entire span of the span, and It is constructed by installing a plurality of X-shaped web members 18, 18 on the left and right sides between the upper and lower floor boards 16, 17.

The upper and lower floor boards 16 and 17 have substantially the same structure as the upper and lower floor boards 3 and 4, but have concavo-convex portions 19 and 20 which are fitted to each other at substantially the center of the front and rear abutting portions. Recesses 21, 21 for joining the end portions of the X-shaped web material 18 are formed in the substantially central portions of the left and right edge portions, respectively. The bottom of the recess 21 is formed thicker to increase the rigidity of this portion (see FIG. 11).

The X-shaped web material 18 has substantially the same structure as that of the brace material 10, and the upper and lower ends thereof are joined to the concave portions 21 and 21 of the upper and lower floor plates 16 and 17 by joining bolts 22 and 22.

Next, the construction method will be explained step by step.

First, the upper and lower floor boards 16 and 17 are connected to each other in the span direction of the main girder 14 one by one, and prestress is introduced for each plurality of boards (see FIG. 12). In this case, the floor boards 16 and
Since 17 is not constrained by the web material at all, a necessary amount of prestress can be introduced, and harmful secondary stress due to prestress does not occur.

Subsequently, X-shaped web members 18 and 18 are respectively installed on the left and right sides between the upper and lower floor plates 16 and 17, and
Connect the upper and lower ends to the recesses 21 and 2 of the upper and lower floorboards 16 and 17, respectively.
1 and connect it with the connecting bolts 22 and 22 (Fig.
(See 11, 13, 14).

The X-shaped web material 18 is pre-configured in a factory or the like like the brace material 10. However, in the case of the PS structure, it is not constrained at all, so a necessary amount of prestress can be introduced. In addition, harmful secondary stress due to prestress does not occur.

Thereafter, in the same manner, the above work is alternately repeated over the entire length of the main girder 15 to assemble the entire length of the main girder (see FIGS. 15, 16 and 17).

[0042]

Since the present invention is configured as described above, it has the following effects.

The PS composite truss structure according to the present invention is
Since it is constructed from the upper and lower floor plates of the PS structure and the web of the truss structure, it is possible to suppress the beam formation as much as possible, structurally eliminate waste, and achieve a lightweight and large span structure.

Further, according to the construction method of the present invention, the prestress is not introduced into the upper and lower floor boards at a time over the entire length thereof, but the units are assembled while introducing the prestress. The stress is bound by the stiff web and its effectiveness is not halved. Therefore, approximately 100% of the introduced prestress can be effectively utilized.

[Brief description of drawings]

FIG. 1 is a partial perspective view of a main girder unit (unit).

FIG. 2 is a side view of a main girder.

FIG. 3 is a side view of a unit assembly (construction unit) including a plurality of units.

FIG. 4 is a cross-sectional view of a joint portion of a PC steel material of a floor board.

FIG. 5 is a cross-sectional view of a web joint portion.

FIG. 6 is an exploded side view showing another embodiment of the unit.

FIG. 7 is a cross-sectional view of the joint of the V-shaped web material of the web.

FIG. 8 is a side view of a main girder.

FIG. 9 is a plan view of a main girder.

FIG. 10 is a vertical sectional view of a main girder.

FIG. 11 is an exploded perspective view showing the structure of the joint between the floor plate and the X-shaped web member.

FIG. 12 is a side view showing an example of a method of constructing a main girder.

FIG. 13 is a side view showing an example of a method of constructing a main girder.

FIG. 14 is a side view showing an example of a method of constructing a main girder.

FIG. 15 is a side view showing an example of a method of constructing a main girder.

FIG. 16 is a side view showing an example of a method of constructing a main girder.

FIG. 17 is a side view showing an example of a method of constructing a main girder.

FIG. 18 is a side view showing an example of a method of constructing a main girder.

FIG. 19 is a cross-sectional view of a conventional main girder.

FIG. 20 is a cross-sectional view of a conventional main girder.

FIG. 21 is a cross-sectional view of a conventional main girder.

[Explanation of symbols]

1 ... Main girder, 2 ... Main girder unit (unit), 3 ... Upper floor plate, 4 ... Lower floor plate, 5 ... Web, 6 ... PC steel material, 7 ... Coupler, 8 ... Vertical material, 9 ... Diagonal material, 10 ... Brace Material, 11 ... P
C steel material, 12 ... Joining bolt or joining pin, 13 ... V-shaped web material, 14 ... Pier, 15 ... Main girder, 16 ... Upper floor board, 17 ... Lower floor board, 18 ... X-shaped web material, 19 ... Recessed portion, 20 ... Convex part, 21 ... Recessed part, 22 ... Joining bolt.

Claims (4)

[Claims] 1. A PC composite truss structure constructed by upper and lower floor plates of a PC structure and a truss structure web installed between the upper and lower floor plates. 2. The PC according to claim 1, wherein the web is constructed as a steel structure or a PC structure.
Composite truss structure. 3. The upper and lower floor boards of the PC structure and the web of the truss structure are divided into a plurality of units, respectively, and each unit is prestressed and assembled to the length of the construction block, and the construction block is prestressed. A construction method for a PC composite truss structure, which is characterized by sequentially erection while introducing. 4. A PS composite truss structure characterized in that the upper and lower floor plates of a PC structure are constructed over the entire length thereof, prestress is introduced over the entire length thereof, and subsequently a web of truss structure is constructed between the upper and lower floor plates. Construction method.