KR20120031626A - Web steel pipe truss i-beam and construction method of the same - Google Patents

Abstract

The present invention relates to a beam for a bridge, and more particularly, a web truss steel having an I-shaped cross-section having a web made of steel pipe truss and preferably having an upper and a lower flange made of concrete, which can be preferably applied to a span between 40 and 80 m. As a composite beam, web steel truss that can add compression prestress to the concrete lower flange as the load increases and can be formed into a box or U-shaped cross-section by connecting the upper and lower flanges of adjacent beams to the site-cast concrete. An eye beam and a method of installing the same.
According to a preferred embodiment of the present invention, a concrete upper flange, a steel pipe truss web assembled with a steel pipe in the form of a truss, and a concrete lower flange form an overall I-shaped cross-section, and the concrete lower flange has a prestress of compressive force introduced during beam fabrication. A web steel pipe truss eye beam is provided.

Description

Web Steel Pipe Truss I-beam and construction method of the same}

The present invention relates to a beam for a bridge, and more particularly, a web truss steel having an I-shaped cross-section having a web made of steel pipe truss and preferably having an upper and a lower flange made of concrete. As a composite beam, web steel truss that can add compression prestress to the concrete lower flange as the load increases and can be formed into a box or U-shaped cross-section by connecting the upper and lower flanges of adjacent beams to the site-cast concrete. An eye beam and a method of hypothesis thereof.

Bridges can be classified in various ways depending on the purpose, the location of the bridges, the planar shape of the superstructure, the material, the type of the superstructure, and so on. It can be classified as a cable-stayed bridge.

A girder bridge is a bridge made mainly of girders or beams, and this girder is called a template. The material of the mold is steel, concrete, or a combination of steel and concrete, and the steel mold includes I-beam or H-beam, plate girder, box girder, etc. There is a PSC girder. Composite girder that combines steel and concrete combines to maximize the advantages of the two materials.It combines high strength concrete under the steel girder with preflection load and removes the reflection load to lower flange concrete. Preflex girder with a prestress of compressive force, corrugated steel sheet I-beam or box girder using corrugated steel sheet as a plural member.

The bridge type must take into account many requirements, but the first consideration is the span. Once the bridge type is determined, the bridge type is finally determined by considering the surrounding conditions, constructability and economic feasibility. Except for the box-shaped cross section, the applicable span of the current type I girder is 30 ~ 45m for PSC beams, 30-50m for rigid composites and 30-50m for preflex series, which is limited to the maximum applicable span. There is this. On the other hand, the self-weight of the girder is closely related to the seismic resistance and the lower construction cost. When the entire cross section is made of concrete, the weight of the girder is uneconomical due to the increase in the self-weight and the reduction of the seismic resistance and the increase in the lower construction cost.

It is an object of the present invention to provide a new type of steel composite beam for bridges that can increase the applicable span of girders having an I-shaped cross section, reduce self weight, increase seismic resistance, and reduce down cost.

It is another object of the present invention to provide a steel composite beam for bridges that can be easily pre-stressed after construction in response to an increase in load for each construction stage, and can be easily re-tensioned when the load capacity decreases.

Another object of the present invention is to provide a composite beam for bridges that can increase the applicable span by connecting the upper and lower flanges of adjacent beams by placing and curing concrete in the field after installing the beams.

The web steel pipe truss eye beam according to the preferred embodiment of the present invention is composed of a concrete upper flange, a steel pipe truss web assembled with a truss in the form of a truss, and a concrete lower flange to form an overall cross-sectional shape of I, and a compressive force when the beam is manufactured on the concrete lower flange. It is characterized by the introduction of prestress.

According to another suitable embodiment of the present invention, a concrete diaphragm portion may be formed at both ends of the beam.

According to another suitable embodiment of the present invention, a secondary tension member may be non-attached to the inside of the concrete lower flange in order to introduce additional tension in response to the increase in load for each construction stage in a certain section between both ends of the concrete lower flange. have.

According to another suitable embodiment of the present invention, a third tension member may be non-attached to the inside of the concrete lower flange in order to introduce a further tension in reducing the load capacity in common in the section between both ends of the concrete lower flange.

According to another suitable embodiment of the present invention, the inclined material constituting the steel pipe truss is joined by a connector and synthesized integrally with the lower flange on the concrete, the connector is a rectangular fixing unit formed with a plurality of through-hole insert holes The first and second protrusions may have a columnar shape extending from the upper or lower portion of the fixing unit at a predetermined angle to correspond to the coupling angle of the inclined material.

According to another suitable embodiment of the present invention, the web steel pipe truss eye beam is manufactured on the ground and installed on the alternating or pier, and then the concrete upper flange and the lower flange of the adjacent web steel pipe truss eye beam are connected by cast-in-place concrete. Provided is a method for constructing a web steel pipe truss eye beam, which is constituted by a cross section.

According to another suitable embodiment of the present invention, the web steel pipe truss eye beam is manufactured on the ground and installed on the alternating or pier, and the concrete bottom flange of the adjacent web steel pipe truss eye beam is connected to the cast-in-place concrete to form a U-shaped cross section. A temporary method for constructing a web steel pipe truss eye beam is provided.

According to the present invention, it is possible to increase the applicable span of the girder having an I-type cross section and to reduce its own weight to increase the seismic resistance and reduce the lower construction cost. In addition, it is possible to introduce additional prestress after construction in response to the increase of load for each construction stage, and it is easy to maintain and maintain because it can be re-tensioned when the load capacity decreases. In addition, after the beam is laid, concrete can be cast and cured at the site to connect the upper and lower flanges of adjacent beams, thereby increasing the applicable span without increasing the weight of the construction.

The following drawings, which are attached in this specification, illustrate the preferred embodiments of the present invention, and together with the detailed description thereof, serve to further understand the technical spirit of the present invention. It should not be construed as limited.
Figure 1a is a perspective view showing a web steel tube truss eye beam according to the present invention, Figure 1b is a front view, Figure 2 is a cross-sectional view (a) is a cross-sectional view taken along the line AA of Figure 1 (b) of Figure 1 It is sectional drawing cut along the BB line.
3 is a perspective view showing a connector according to the present invention.
4 is a perspective view showing a web steel tube truss eye beam according to another embodiment of the present invention, Figure 5 is a cross-sectional view (a) is a cross-sectional view taken along the line CC of Figure 4 (b) is a DD line of FIG. Sectional view cut along the side.
Figure 6 is a cross-sectional view showing an example in which the web steel pipe truss eye beam according to the present invention is configured in a box-shaped cross-section using in-cast concrete.
7 is a cross-sectional view showing an example in which the web steel pipe truss eye beam according to the present invention is constructed in a U-shaped cross section using in-situ concrete and a bridge deck is constructed.

In the following the present invention will be described in detail with reference to the embodiments shown in the accompanying drawings, but the embodiments presented are exemplary for a clear understanding of the present invention is not limited thereto.

Figure 1a is a perspective view showing a web steel tube truss eye beam according to the present invention, Figure 1b is a front view, Figure 2 is a cross-sectional view (a) is a cross-sectional view taken along the line AA of Figure 1 (b) of Figure 1 It is sectional drawing cut along the BB line.

1 and 2, the web steel pipe truss eye beam according to the present invention is composed of a concrete upper flange 11, a steel pipe truss web 12 and a concrete lower flange (13). The prestress of compressive force is introduced into the concrete lower flange 13 when the beam is manufactured using the tension member 131 disposed therein as in the conventional PSC beam. That is, the web steel pipe truss eye beam according to the present invention may be referred to as a substitute for a truss composed of structural steel pipes in the I-type PSC beam. Meanwhile, concrete diaphragms 15 may be formed at both ends of the beam to increase the rigidity of the end portion, to facilitate the continuity of the branch portions, and to effectively resist the parent moment acting after the branch portion continuity.

In the present invention, the web member is manufactured in the form of a truss using a structural steel pipe, and a junction (node) is joined using a connector 14 to be described later, and is integrated with the concrete upper flange 11 and the concrete lower flange 13 integrally. The steel pipe truss web 12 has a shape in which two inclined members 121 and 122 are continuously disposed symmetrically with respect to the intercenter line so that the direction of the inclined material goes outward from the top to the bottom of the intercenter. That is, in the warren truss well known in the art, it has the same arrangement form as the arrangement of the inclined material, and if necessary, it is possible to divide the space between the secondary fabric. However, the shape of the steel pipe truss in the present invention is not limited to this, it is possible to arrange the inclined material in the same manner as howe truss or pratt truss well known in the art.

As described above, the beam according to the present invention has a truss structure of the web, which enables long spans of 40 to 80 m and enables low height and reduces the weight of the beam. When it is applied to the cross section bridge between long and low blast furnaces, it is advantageous to secure the communication surface and reduce the self-weight so that the seismic resistance is improved and the lower construction cost is reduced. In addition, because the beam manufacturing process is mainly performed in the factory, the quality is improved, the air is shortened, the manufacturing site is unnecessary, and the workability is excellent. In addition, the prestress is introduced into the lower flange of the concrete to provide excellent stability against cracking.

The gaps of the inclined members 121 and 122 of the steel pipe truss constituting the web member in the beam according to the present invention are joined through the connector 14 and synthesized integrally with the concrete flanges and the lower flanges 11 and 13.

3 is a perspective view showing a connector according to the present invention.

Referring to FIG. 3, the connector 14 includes a fixing unit 141 and first and second protrusions 142a and 142b for joining steel pipes extending from an upper part or a lower part thereof.

The fixing unit 141 is a portion embedded in the concrete upper flange 11 or the concrete lower flange 13 may be a rectangular shape having a predetermined thickness and width, and a plurality of through-hole reinforcement holes 141a are formed. Insertion hole (141a) is to install the through-hole reinforcement (141b) to increase the synthesizing effect of the connector 14 and the concrete upper flange 11 or the connector 14 and the concrete lower flange 13 so that they behave integrally. . The fixing unit 141 may have a thickness that is equal to or smaller than the diameter of the first and second protrusions 142a and 142b, and may form a hollow part therein to reduce weight.

The first and second protrusions 142a and 142b are formed to extend from an upper portion or a lower portion of the fixing unit 141 and have a predetermined angle to correspond to the coupling angles of the inclined members 121 and 122 of the steel pipe truss. The first and second protrusions 142a and 142b have a shape, a diameter, and a length corresponding to the cross-sectional shape of the inclined members 121 and 122 so that one end of the inclined members 121 and 122 can be inserted to a predetermined depth. That is, when the inclined members 121 and 122 are circular steel pipes, the first and second protrusions 142a and 142b may have a cylindrical shape, and when the inclined members 121 and 122 are square steel pipes, the inclined members 121 and 122 may have a square pillar shape. It may have a shape corresponding to the shape of). One end of the inclined members 121 and 122 may be inserted into the first and second protrusions 142a and 142b and joined to each other by bolts or welding. A plurality of screw holes or through holes 1421 may be formed in the first and second protrusions 142a and 142b at regular intervals along the length direction for the bolted joint, respectively. The first and second protrusions 142a and 142b may be configured as solid solid bodies, but may be configured as hollow pipe shapes to reduce weight. When the first and second protrusions 142a and 142b have a hollow pipe shape, the inclined members 121 and 122 may be inserted into the hollows of the first and second protrusions 142a and 142b and joined by bolts or welding. .

The fixing unit 141 and the first and second protrusions 142a and 142b may be integrally formed by casting using steel materials.

The connector 14 configured as described above is inclined members 121 and 122 and the concrete upper flange 11 and the inclined members 121 and 122 and the concrete lower flange 13 in the present invention using a steel pipe as a truss by arranging the steel pipe in a truss shape. Can be used to connect them together. The fixing unit 141 is embedded in the concrete lower flange 13 or the upper flange 11 and functions to allow the inclined members 121 and 122 and the concrete upper flange 11 or the lower flange 13 to be integrally synthesized. Increase the synthesis of wah.

In the beam according to the present invention, a secondary tension member may be disposed to additionally introduce prestress in response to an increase in load for each construction stage, and a third tension member may be disposed to enable retension when the load capacity decreases.

4 is a perspective view showing a web steel tube truss eye beam according to another embodiment of the present invention, Figure 5 is a cross-sectional view (a) is a cross-sectional view taken along the line CC of Figure 4 (b) is a DD line of FIG. Sectional view cut along the side.

As shown in Figure 4 and 5 (a), it is possible to install a sheath tube (not shown) inside the concrete lower flange 13 and to arrange the secondary tension member 132 therein and the secondary tension member 132 ), Additional tension can be introduced in response to an increase in load at each construction stage. That is, the secondary tension member 132 is installed not to be attached to the concrete lower flange 13 to enable post-tensioning. Therefore, any method known in the art may be applied to install the tension member to be non-attached, in addition to installing the sheath tube and disposing the secondary tension member 132 therein. The secondary tension member 132 may introduce tension to the concrete lower flange 13, for example to counteract additional loads acting on the beam after slab concrete placement.

Next, as shown in FIGS. 4 and 5 (b), a sheath tube (not shown) may be installed inside the concrete lower flange 13 and a third tension member 133 may be disposed therein, and the third The tension member 133 may be used to introduce additional tension in response to an increase in load for each construction step. That is, the tertiary tension member 133 is installed so as not to be attached to the concrete lower flange 13 to enable post tensioning like the secondary tension member 132. Therefore, in addition to disposing the sheath tube and disposing the tertiary tension member 133 therein, any method known in the art may be applied. The tertiary tension member 133 may maintain the beam continuously by, for example, straining when the load capacity decreases during common use.

As shown in FIG. 4, fixing blocks 132a and 133a for fixing the secondary tension member 132 and the tertiary tension member 133 are installed to be exposed to the upper surface of the concrete lower flange 13 to facilitate additional tensioning. Make it happen.

On the other hand, in the present invention, by placing the beam in the field after placing the beam, by connecting the upper and lower flanges of the adjacent beam to configure the box-shaped cross-section can increase the applicable span.

Figure 6 is a cross-sectional view showing an example in which the web steel pipe truss eye beam according to the present invention is configured in a box-shaped cross-section using in-cast concrete.

Referring to FIG. 6, a box-shaped cross section may be configured by connecting two upper and lower flanges according to the present invention mounted on a pier 20 by using cast-in-place concrete. Specifically, in order to connect the adjacent concrete upper flange 11 is installed in the concrete upper flange 11 to expose a portion of the upper connection reinforcing bar 111 in advance when the beam is manufactured. Thus, the beam is installed on the top of the bridge 20, the beam is installed on top of the bridge (20), and then cast the upper connection concrete (15), the curing is connected to the adjacent concrete upper flange (11). In the same way, in order to connect the adjacent concrete lower flange 13, the lower connection reinforcing bar 134 is installed inside the concrete lower flange 13 so that a part of the lower connection bar is exposed in advance when the beam is manufactured, and the lower connecting concrete 16 is poured. Curing and connecting the adjacent concrete lower flange (13). At this time, a sheath tube (not shown) is installed inside the lower connection concrete 16 and the tension member 161 is disposed in the sheath tube, and then the lower connection concrete 16 reaches the predetermined strength and then the tension member 161 is removed. By tensioning the prestressing force of the compressive force can be introduced into the lower connecting concrete 16. Thus, in the present invention by connecting the beam to the box-shaped cross-section in the field as compared to manufacturing, transporting, and placing the girders of the box-shaped cross-section it is easy to transport and can significantly reduce the weight of the construction, it is possible to be longer. In addition, there is an advantage that there is no need to construct a bridge deck separately.

7 is a cross-sectional view showing an example in which the web steel pipe truss eye beam according to the present invention is constructed in a U-shaped cross section using in-situ concrete and a bridge deck is constructed.

In the embodiment shown in FIG. 6, a box-shaped cross section was constructed by connecting two upper and lower flanges according to the present invention mounted on a pier 20 by using cast-in-place concrete. On the contrary, in the embodiment shown in FIG. 7, the lower flange 13 is connected using the lower connection concrete 16 that is cast in the same place as the embodiment shown in FIG. 6 to form a U-shaped cross section, and the upper flange 11 The bridge bottom plate 30 is poured.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention . The invention is not limited by the invention as such variations and modifications but only by the claims appended hereto.

11: concrete upper flange
12: steel pipe truss web
121, 122: slope
13: concrete bottom flange
131: tension
132: secondary tension material
133: tertiary tension
14: connector
141: fusing unit
142a: first protrusion
142b: second protrusion

Claims (7)

It consists of a concrete upper flange, a steel pipe truss web assembled in a truss shape, and a concrete lower flange to form an I-shaped cross section overall, and a web steel pipe truss eye beam characterized in that pre-stressing of compressive force is introduced into the concrete lower flange. . The method according to claim 1,
A web steel pipe truss eye beam, characterized in that a concrete diaphragm portion is formed at both ends of the beam. The method according to claim 1,
Web steel tube truss eye beam, characterized in that the secondary tension material is installed in the non-attachment inside the concrete lower flange in order to introduce additional tension in the predetermined section between the both ends of the concrete lower flange in accordance with the increase in load for each construction stage. The method according to claim 1,
Web steel pipe truss eye beam, characterized in that the third tension material is installed in the lower portion of the concrete lower flange in order to introduce additional tension when the load reduction in common load in a certain section between both ends of the concrete lower flange. The method according to claim 1,
The inclined material constituting the steel pipe truss is joined by the connector and synthesized integrally with the concrete flange, the lower flange,
The connector,
A rectangular fixing unit having a plurality of through-hole insertion holes formed therein;
A web steel pipe truss eye beam, characterized in that it comprises a columnar first and second protrusions extending at a predetermined angle to correspond to the coupling angle of the inclined material in the upper or lower portion of the fixing unit. After the web steel pipe truss eye beam according to any one of claims 1 to 5 is manufactured on the ground and installed on the alternating or pier, the concrete upper flange and the lower flange of the adjacent web steel pipe truss eye beam are connected by cast-in-place concrete. The construction method of the web steel pipe truss eye beam, characterized in that the box-shaped cross section. The U-shaped web steel pipe truss eye beam according to any one of claims 1 to 5 is manufactured on the ground and installed on the alternating or pier, and then connected to the concrete bottom flange of the adjacent web steel pipe truss eye beam with cast-in-place concrete to form a U-shape. A temporary method for constructing a web steel pipe truss eye beam, comprising a cross section.

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