KR200234512Y1 - The preflex composite beam made by unite the hunch concrete represtressing the lower casing concrete - Google Patents

Abstract

This design compensates for the welding residual stress of steel and the compressive stress loss of lower casing concrete due to creep and dry shrinkage of concrete. The method of introducing additional compressive stress into the lower casing concrete by applying upward load by installing branch points such as copper barges is used. However, the free compressing stress can be introduced into the lower casing concrete without any additional material or additional process. The present invention relates to a flex composite beam. To this end, this design applies a force to the center of the composite beam on the ground, not on the alternating or pier, to introduce additional compressive stress to the lower casing concrete, and places hunt and abdominal concrete for introducing additional prestressing under force. After curing, the force is removed to compensate for the reduced compressive stress of the lower casing concrete. According to this design, it is more concise than the conventional manufacturing method and the material usage can be significantly reduced.

Description

The preflex composite beam made by unite the hunch concrete represtressing the lower casing concrete}

The present invention relates to a preflex composite beam using a hunch for introducing additional prestressing, and the conventional techniques include a 're-prestress steel composite beam manufacturing method' (FIG. 2) and a 'simple beam-free using a supporting point. Manufacturing method of the flex composite beam '(FIG. 3).

Figure 2 shows the process of the 're-prestress' of the composite beam as a way to supplement the compressive stress of the lower casing concrete (30) by introducing a compressive stress using a tension PC-PC additionally.

Figure 3 shows the process of 'fabrication method of the simple beam preflex composite beam using the supporting point'. Fig. 3 (a) shows that the lower casing concrete 30 is placed and cured in the state of loading the pre-flection load on the I-type steel, and then mounted between the shifts to install branch points at the center of the ground, and to creep and dry shrinkage of the initial concrete. In order to compensate for the loss of compressive stress caused by the rising point (↑) is a state diagram that introduces the additional compressive stress to the lower casing concrete. Figure 3 (b) shows the process of placing and curing the upper floor plate concrete and the abdominal concrete in a state where the branch point is raised. Figure 3 (c) is a state diagram to remove the branch (↓) after the upper base plate concrete and the like is cured.

As described above, the composite beam of FIGS. 2 and 3 can introduce compressive stress to the lower casing concrete 30 as compared to the conventional preflex composite beam fabrication process manufactured as shown in FIG. It works. However, the process of FIG. 2 composite beam adds tension material to the preflex composite beam, which is not only cumbersome to produce, but also requires additional costs such as tension cost of the tension material. It becomes a complicated structure. In addition, since the composite beam of FIG. 3 is mounted on the alternating or pier, the branch beam should be installed at the center to apply an upward load. You will be restricted from using it. For example, when applied to bridge construction, it disrupts traffic flow in bridge spaces, and in case of rivers, it interferes with flowing traffic. When applied to buildings, parallel work is hindered by the ascending facilities of branches. You will need additional air.

The present invention aims to provide a realistic, practical and economical composite beam in which compressive stress is introduced into the lower casing concrete by using an additional prestressing introduction hunt without the use of additional materials or extra processing to solve the above problems. do.

1 is a conventional preflex composite beam manufacturing process diagram

Figure 2 is a principle diagram for introducing additional compressive stress by prestressing the tension material in the conventional preflex composite beam

Figure 3 is a pre-fabricated composite beam manufacturing process using a conventional branch

Figure 4, Figure 5 is a preflex composite beam and a continuous manufacturing process using the haunch for introducing additional prestressing according to the present invention

Explanation of symbols on the main parts of the drawings

10 is the haunt for introducing additional prestressing

20 is the lower flange

30 is under casing concrete

In order to compensate for the reduction of the compressive stress of the lower casing concrete produced during the production of the preflex composite beam, this design adds additional compressive stress means. The lower casing concrete and the lower casing concrete are placed under upward load so that the additional compressive stress is introduced. A prestressed composite beam constructed as a haunt for introducing additional prestressing to be introduced.

According to this design, the center of the composite beam is applied on the ground, not on the alternating and piers, and after the cross section is expanded, the hunt for introducing additional prestressing (10) and abdominal concrete is poured and cured. Compensating the compressive stress reduction of the lower casing concrete 30 by removing the force, there is no complexity in terms of material and structure compared to the composite beam of Figure 2, the branch point using a copper bar, etc. in the alternating and pier compared to the composite beam of Figure 3 This reduces the risk of additional processes, costs and safety incidents associated with the installation, thus solving the problems of the cited technologies listed above.

This invention will be described in more detail with reference to the accompanying embodiment drawings.

As shown in FIG. 4 (a), the I-type steel is made to rise upward and mounted at both ends. Then, when the loads P1 and P1 are applied within the elastic range as shown in FIG. 4 (b), tension occurs in the lower flange 20 according to the bending force. do. In this state, as shown in Fig. 4 (c) is cast to the lower casing concrete 30 wrapped around the lower flange 20 and cured. Next, as shown in Figure 4 (d) to remove the load P1, P1 and introduce a compressive stress to the lower casing concrete 30 as a restoring force of the I-type steel. At this time, the lower casing concrete 30, the welding residual stress and the creep and dry shrinkage of the concrete acts to reduce the compressive stress of the lower casing concrete 30 by a certain amount. In order to further introduce the reduced compressive stress, load P2 is applied upwards as shown in Fig. 5 (e) on the ground, not on the alternating and pier, to introduce additional compressive stress to the lower casing concrete 30 and to apply the load P2. In the state as shown in Figure 5 (f) additional prestressing introduction hunt 10 and the abdominal concrete is poured. At this time, the additional pre-stressing introduction haunchi 10 acts as a bottom plate concrete when the load P2 is removed, so that the cross section is enlarged and square or trapezoidal or high-strength concrete compared to the existing haunch to sufficiently support the compressive stress. After the haunch 10 for introducing additional prestressing and the abdominal concrete are cured, as shown in FIG. 5 (g), when the upward load P2 is removed (↓), the haunch 10 for introducing additional prestressing is applied to the dead load acting downward. In addition, the compressive stress is introduced in addition to the lower casing concrete (30). Thereafter, as shown in Figure 5 (h) is mounted on the preflex composite beam on the alternating and piers and placing the bottom plate concrete.

As described above, this design can drastically reduce the amount of steel used compared to the conventional prestressed composite beams, and it is very easy to improve the process hassle and structural complexity when compared to the conventional method of introducing additional compressive stress using the tension material. Compared to the method of introducing additional compressive stress by using branch points, it is possible to avoid cost burden, inconvenience, and risk of using lower spaces because of the installation of branch points. It can be effective.

Claims (1)

In order to compensate for the compressive stress reduction of the lower casing concrete produced during the production of the preflex composite beam, an additional means for introducing the compressive stress is added. In order to add additional compressive stress to the concrete and lower casing concrete, the concrete is placed on the haunch and abdomen with the upward load to cure, and then the upward acting force is removed to remove the upward acting force. Prestressed composite beam constructed as a haunch for introducing additional prestressing.