KR20030042267A - method for manufacturing prestressed composite beam by division mode - Google Patents

Abstract

PURPOSE: A manufacturing method of a prestressed composite beam is provided to have a good command of chamber for a joint and to place compressive force evenly. CONSTITUTION: The manufacturing method of a prestressed composite beam comprises the steps of: chambering a spot to be divided using a unified steel beam according to a plan of a prestressed beam in a factory; adding preflexion load on the chambered steel beam; at the state of adding preflexion load, placing and curing lower casing concrete on a spot excluding a split line out of a lower flange of a steel beam; after curing the lower casing concrete surface, removing preflexion load and cutting off a part where lower casing concrete isn't placed into many members; lining up each member on a temporary support in a job site, and fixing a joint of each member to the ground by a wire rope; lifting up the temporary support to be chambered, then placing and curing joint casing concrete(8) on a joint of each member; after curing the joint casing concrete(8), descending the temporary support slowly and adding compressive force on joint concrete.

Description

Method for manufacturing prestressed composite beam by division mode

The present invention relates to a new method of fabricating a prestressed composite beam.

Conventional member split type prestressed composite beams are manufactured only in the factory due to problems in transportation, and transported to the bridge construction site, welded the members in a widely secured workshop, and finished with prestressed composite beams on the production platform. Construction has been carried out in the order of placing concrete on top of the bridge using cranes and then placing concrete on the upper deck.

Bridge construction sites require a workshop for the production of wide prestressed composite beams of at least 3000 m2. In addition, the prestressed composite beam production workshop on the site should be wide and flat, and the welding of the beams should be less influenced by wind and closer to the bridge construction site on the street. In order to meet these conditions, the cost is enormous, and on-site member welding is difficult to control quality.

Conventional member splitting type prestressed composite beam steel, that is, the member is divided into three or four pieces of steel having a required length as illustrated in FIG. 1 to form a plurality of members, and the connecting portion of each member is welded or a connecting plate and a high tension bolt. After the connection is made, the compressive force is introduced by a method such as bending load. The connection part of each member gives a contact acute angle in consideration of the deformation of the steel by the preflection load.

The joints of each member are raised to apply the deflection load to the manufactured steels so that the steels are bent. In this state, as shown in FIG. 2, the lower casing concrete is poured into the lower flange of the steel, and when the lower casing concrete is cured, the preflection load is gradually removed.

However, this method is difficult to precisely control the amount of rise to the connection part of each member, and it is difficult to introduce even compressive force due to the sudden bending at the connection part when loading the bending load.

Accordingly, an object of the present invention is to provide a prestressed composite beam that promotes the accuracy of the rising amount of the connecting portion of the members, evenly compressive force, and can be easily assembled and constructed regardless of the occupational footprint of the bridge construction site. It is.

The present invention minimizes the errors that may occur in processes such as rising amount and bending load by making a steel mold with a single steel without a member between parts in a factory.

In addition, after the curing of the lower casing concrete except for the portion divided from the lower flange in the state of the pre-flection load is loaded on the single-type steel, the portion of the lower casing concrete is not poured in the state where the removal of the flexion load is removed By introducing a compressive force, an even compressive force is introduced.

Then, each member is transported to the bridge construction site, placed on the temporary support, and the compressive force is introduced, and the joint casing concrete is poured into the lower flange of the connection to cure, and then the temporary support is gradually removed to introduce the compressive force to the connecting casing concrete. It is characterized by obtaining a prestressed composite beam exhibiting perfect capability.

1 is a front view of a conventional prestressed composite beam illustrating the site under preflection load;

2 is an exploded view of the member of FIG.

3 is a front view of a steel for prestressed composite beams providing the sheath of the present invention

4 is a front view of a state in which a preflection load is applied;

5 is a front view in the case where the lower casing concrete is poured on the lower flange while the preflection load is applied;

Figure 6 is released by removing the bending load after curing the lower casing concrete

Front view of the prestressed composite beam member divided into prestressed beams

7 is a front view of the prestressed composite beam assembled while supporting the prestressed composite beam member as a temporary support at a bridge construction site;

8 is fixed to the ground by the fixing device to the assembled prestressed composite beam

Front view of the condition

9 is a front view in the case where the connection concrete is poured into the connection portion of the prestressed composite beam

10 is a front view of a state where the temporary support is removed

11 is a state diagram in which the prestressed composite beam is installed on a piers;

12 is a state diagram in which the top concrete and the abdominal concrete of the prestressed composite beam

<Explanation of symbols for the main parts of the drawings>

1: Steel type 1a, a ', b: member

2: rising 3: preflection load

4: lower flange 5: lower casing concrete

6: temporary support 7: steel

8: connection concrete

In FIG. 3, the rigid 1 is unitary as designed and gives a predetermined rise 2 to the point to be split at the plant.

In FIG. 4, the rise 2 is bent downward by applying a preflection load 3 to a given rigid 1.

In FIG. 5, the lower casing concrete 5 is poured in the part except the dividing line part of the lower flange 4 of the steel mold 1 in the state which the preflection load 5 was loaded. Then, when the lower casing concrete 5 is cured, the preflection load 5 is gradually removed.

In Figure 6, the lower casing concrete (5) is cut to the portion (6) is not poured, divided into a plurality of members (1a, 1b, 1a ') and transported to the bridge construction site.

In Fig. 7, each member 1a, 1b, 1a 'is placed in a row on a temporary support 6 such as a hydraulic jack at a bridge construction site.

In Fig. 8, the connecting portions of the respective members 1a, 1b, 1a 'are fixed to the ground with steel materials such as wire ropes.

In Fig. 9, after raising the temporary support 6 in this state, the high-strength concrete is poured into each connection portion to cure the connection casing concrete 8.

In FIG. 10, when curing of the connection casing concrete 8 is completed, the temporary support 6 is slowly lowered to introduce a compressive force to the connection concrete 8. Then remove the temporary support (6) and the steel (7).

In FIG. 11, the prestressed composite beam 9 completed by assembly in this order is hypothesized on the top of the piers 10, and as shown in FIG. 12, the top concrete 12 is formed on the upper flange 11, and the abdominal concrete ( Construct the bridge by pouring 13).

The member split type prestressed composite beam of the present invention as described above is capable of accurately using the amount of rise to the member joint by dividing after curing the lower casing concrete by loading and preflection load on the monolithic steel, and also compressive force. It can be introduced evenly.

In addition, it is possible to reduce the burden and cost burden because it occupies the occupied area when the concrete is connected and cured by removing the temporary support while completing the transportation by assembling the bridge construction site and raising it with temporary support. .

Claims (1)

Giving a predetermined rise to a point to be divided, using a steel unit which is unified according to the design length of the prestressed beam in the factory; Applying a preflection load to the steel given the rise; Placing and curing curing of the lower casing concrete at a portion other than the dividing line portion of the lower flange of the steel under the pre-loading load; Removing the preflection load after the lower casing concrete is cured and cutting a portion of the lower casing concrete in which the lower casing concrete is not poured and dividing it into a plurality of members; Placing each member in a row on a temporary support at a bridge construction site and fixing the connection portion of each member to the ground with steel such as a wire rope; Raising the temporary support and pouring the casing concrete at the connection part of each member to cure; Connection casing After curing the concrete, the temporary supporting beam is gradually lowered to introduce a compressive force to the connection concrete.