KR100310301B1 - Leaf-restrest box girder composite bridge - Google Patents

Abstract

The present invention, unlike the conventional I girder composite type, by manufacturing a box girder composite type having an upward force due to the preflex, overcomes the shortcomings of short span, orthogonal, high-speed railway passing the disadvantages of the conventional I girder composite type A new concept of prestressed rigid composite box girder bridges that resists hard, bridge, high speed and heavy vehicle loads.

The present invention is composed of a box-shaped steel girder formed of a steel plate in which the upper flange is synthesized in the span of the slab, and the lower flange is installed over the entire length of the lower flange of the steel girder. By constructing a closed cross-section is connected to the torsional stiffness by 37 times to solve the problem of low rigidity, instability of the existing bridge. In addition, if required by the site requirements, the prestressing method can be applied in addition to the prestressing method for compressing the lower concrete by the preflex, and the torsional rigidity and the bending rigidity can be increased because the cross-sectional shape is in the form of a box.

Description

Lift List Box Girder Composite Bridge (THE COMPOSITE BRIDGE OF REPRESTRESSED PREFLEX BOX GIRDER)

The present invention is different from the conventional represtressed preflex (hereinafter referred to as "RPF") I girder composite girder I girder which is a structural unit of the box girder composite type as a structural unit The present invention relates to a girder composite bridge and a construction method thereof, and more particularly, to a leaf restraint box girder composite bridge having economical stability, construction and construction in a two- and three-room box girder.

In general, in composite bridges, the stresses on steel beams and deck concrete under the specified loading conditions must satisfy the conditions below the allowable stress. In this case, there is no problem in a simple beam, but a negative bending moment due to dead or live load acts on the point portion of the continuous beam to generate tensile stress. In order to process the tensile stress generated in the bottom plate concrete, it is necessary to introduce the prestress due to the rising or falling method of the point portion, the tension of the PC steel bar, etc., and thus the design and construction tend to be complicated.

In general, the design of continuous composite bridges such as two span bridges and three span bridges is regarded as composite in the range of (+) bending moment and non-synthesis in the range of (-) bending moment. I design it. At this time, the tensile stress is generated in the concrete deck of the (-) bending moment portion, which causes cracks in the concrete deck. In order to prevent this, in the conventional composite bridge design and construction as described above, in order to suppress the crack progression, the prestressing by the tension material is added to the axial direction of the concrete deck plate portion to allow the tensile stress acting on the concrete deck. It can be controlled within.

Here, the RPF I-gerger composite type is reinforced concrete slab 101 having a constant effective width as shown in Figure 1, and the steel girder 102, the upper flange is synthesized and supported on the slab 101, It is composed of a lower flange concrete 103 and the abdominal Ron concrete 104 installed in the lower flange and the upright beam of the steel girders 102, and tendons 105 installed in the lower flange concrete 103, The type I steel girder and the PC strand supporting the slab are made of a non-bonded state, and the tension of the lower flange concrete is suppressed by retensioning using non-bonding tendons to the lower flange concrete of the preflex bridge. One bridge.

The structure is low in shape and ensures stability during use due to the maximum load during construction, and can suppress the occurrence of concrete cracks in the lower flange, while the significant construction density and reinforcement of the lateral support device under the preflex load There is a problem that can not be applied to the installation of long sections, bridges, curved bridges because it is required, because vibration is generated. In addition, stress on the lower concrete is applied.

Preplex composite type is a bridge that combines type I girder with reinforced concrete. Compression prestress is introduced to concrete surrounding steel tensile flanges in advance to offset tensile stress caused by dead and live loads. While the structure has an advantage of low mold height, there is a great cracking in the lower flange concrete of the currently constructed bridge, so the maintenance cost according to the crack repair and reinforcement is increased, and the construction process density is required under the preflex load. .

As described above, the preflex bridge and the RPF composite bridge can cause lateral buckling if precision construction is not performed, and the lack of torsional rigidity implies a problem of causing vibration for bridges, curved bridges, long bridges, and high-speed loads. have.

Meanwhile, the P.C I beam bridge is a structure in which a P.C strand is bonded to a reinforced concrete slab, and is a post tension bridge that reduces the moment of the constant moment section by using the PC steel wire and the steel bar. This structure has relatively high crack safety factor, suitable for about 20m ~ 30m span, low construction cost, and simple construction, while high mold height, and can be conducted before and after installation and continuous maintenance. There is a problem in that it is disadvantageous in travelability and in seismic design.

PC box type combines PC strand with non-bonded reinforced concrete slab. It is manufactured as a box to increase cross-sectional stiffness, and after PC strand is properly arranged, it is applied by post tensioning and according to construction method, FSM, FCM, ILM It is a bridge that is hypothesized by the MSS. This structure has a low mold height and has the advantage of suppressing the occurrence of cracks in the lower flange concrete, but is prone to cracking in the prestressed anchorage, disadvantageous installation of curved bridges, complicated construction relationships, and long construction periods. There was this.

Steel box girder bridge is a structure where concrete slab is combined with steel girder. It is mainly used for long bridges due to its rigidity. The proper span has a length of 50m in simple beams and 60m in continuous beams. This structure is of high quality, easy to install, good aesthetics, and suitable for curved bridges and social bridges, while high in construction, corrosion, and excessive maintenance costs. There is a problem that the top plate crack occurs due to excessive deflection.

Accordingly, the present invention has been made in order to solve the above-mentioned problems, the pre-stressing by the preflex is introduced into the box-girder or the T-girder connecting at least one of the upper and lower flanges in a continuous form, and the concrete slab and Its purpose is to provide a resilient composite bridge that can be applied to long span bridges, continuous bridges, bridges, high-speed railway bridges, etc., by increasing the flexural and torsional stiffness after the completion, and preventing lateral buckling.

In addition, the present invention provides a resistant girder composite bridge for adding prestressing by tension material in the axial direction to the prestressing method for compressing the lower concrete by the preflex in the field condition or when the cross section is insufficient. There is another purpose.

It is another object of the present invention to provide an economical and stable leafyrest girder composite bridge.

1 is a cross-sectional view showing the configuration of a releasant restraint type I girder composite bridge according to the prior art.

2a to 2g is a construction flowchart of the releasant box girder composite bridge according to the present invention.

Figure 3 is a basic cross-sectional view showing the configuration of one embodiment of a composite bridge of a leaf restraint box girder according to the present invention.

Figure 4 is a two-section basic cross-sectional view showing the application state of the leaf restraint box girder according to the present invention.

Figure 5 is a two-threaded basic cross-sectional view showing an application state of the leafrest box girder according to the present invention.

Figure 6 is a three-section basic cross-sectional view showing the application state of the leaf restraint box girder according to the present invention.

7 is a first modified exemplary view of a leaf restraint box girder composite bridge according to the present invention.

8 is a second modified exemplary view of a leaf restraint box girder composite bridge according to the present invention;

9 is a third modified exemplary view of a leafrest box girder composite bridge according to the present invention;

Figure 10a is a fourth modified example of the leaf restraint box girder composite bridge according to the present invention.

10b is a fifth modified example of the leafrest box girder composite bridge according to the present invention;

11 is a sixth modification of the leaf restraint box girder composite bridge according to the present invention.

12 is a seventh modified view of a leaf restraint box girder composite bridge according to the present invention;

13a to 13d is a configuration diagram of the RP-BOX girder composite type having a steel girder or steel plate-shaped cross section of the maximum moment generating point in the axial direction in the leafrest box girder composite bridge according to the present invention.

* Explanation of symbols for main parts of the drawings

1: reinforced concrete slab 2: steel girder

3: box concrete 4: load balancing concrete

5, 5 ': tendon 6: reinforcement

7: torsion reinforcing member 8: cross-section reinforcing steel sheet

9: single reinforcing material 12: deck plate

The present invention to achieve the above object, the reinforced concrete slab having a predetermined width; It is installed and supported every predetermined span of the slab, the upper flange is synthesized in each of the slab span, the lower flange is formed of one of a continuous steel frame or steel sheet to form a box shape, the steel frame or steel sheet One or more steel girders loaded with a vertically downward preflex load; And it is provided over the entire length of the lower flange of the steel girder to provide a relief rest box girder composite bridge comprising a box concrete for supporting the steel girder.

In addition, the present invention is a reinforced concrete slab having a predetermined width; A doe steel girder installed and supported at every predetermined span of the slab, the upper flange of which is synthesized in the respective slab spans, and a single reinforcing material is installed on the lower flange to form a box shape; Sectional force reinforcing plate continuously installed on the upper flange of the steel girder; A tendon installed to prestress the slab; And a box concrete supporting the steel girder and installed over the entire length of the upright beam and the lower flange of the steel girder, thereby providing a leafrest box girder composite bridge for treating a continuous bridge parent section.

In order to prevent the lower part of the existing I-type girder composite type bridge from being separated and deteriorating stability and stiffness, the present invention having the characteristic configuration as described above has a closed section connected to the lower part as shown in FIGS. In addition, the torsional stiffness was increased by more than 37 times to solve the problem of low rigidity and instability of the existing bridge. If required by each site requirement, prestressing by tension material may be applied in addition to the prestressing method of compressing the lower concrete by the preflex.

Hereinafter, with reference to the accompanying drawings of Figure 2 will be described an embodiment of the present invention;

Leafrest box girder composite bridge according to the present invention is implemented to have sufficient torsional rigidity and stability, the present invention is mainly applied to long bridges, bridges, continuous bridges, high-speed railway bridges, the structure is as follows.

Bridge of the present invention is a reinforced concrete slab (1) having a predetermined width as shown in Figure 3; It is installed and supported at every predetermined span of the slab, and the upper flange 2a is synthesized in the span of each slab 1, and the lower flange 2b is integrally formed in the horizontal beam-shaped steel frame or the axial direction. One or more steel girders (2) formed in one of the plate-shaped steel plates to form a box shape, and having a vertical downward preflex load on the steel frame or steel plate; It is composed of a box concrete (3) installed over the entire length of the lower flange (2a) of the steel girder (2) to support the steel girder (2).

Here, the steel girder 2 has an I-shaped cross section, and is divided into a plurality of threads or a plurality of boxes depending on the width of the bridge. For example, when the bridge width is 13m or less, the steel girder 2 is composed of one chamber (shown in FIG. 3), two chambers in 13-18m (shown in FIG. 5), and two weeks (twin) in 18-25m. box) (shown in FIG. 4) is preferable.

In addition, the lower flange 2b has a structure in which only a vertical downward preflex load is loaded, but prestressing may be applied in the axial direction.

The box concrete (3) may be divided into a lower flange concrete (3a), the abdominal concrete (3b), in the present embodiment, the abdominal concrete (3b) on the outer peripheral surface of the upright beam of the steel girder (2) to a predetermined thickness It is installed structure. In this structure, painting work to prevent corrosion on the inner surface of the upright beam of the steel girder 2 should be performed.

In the present embodiment, the structure in which the abdominal concrete is poured only on the outer circumferential surface of the upright beam of the steel girder 2 is not limited thereto, and the inner concrete 3b ′ shown in phantom in FIG. 3 is steel girder 2. In the upright beam inside) can also be cast to a predetermined thickness, at this time, the painting work of the steel girder (2) is not necessary. In addition, when considering the internal workability, the abdominal concrete 3b may not be installed on the upright beam of the steel girder 2.

A lower flange concrete 4 having a thickness of about 20 to 40 cm is installed on the upper portion of the lower flange 2b of the steel girder 2, and the most preferable concrete thickness is 30 cm.

A plurality of tendons 5 are installed in the inside of the box concrete 3 to apply prestress to the box concrete 3, and the tendons 5 are also disposed on the abdominal concrete 3b installed on the outer circumferential surface of the upright beam of the steel girder 2 at regular intervals. The prestressing tendon 5 can be changed in number and position according to the cross-sectional force by installing and applying prestress.

Referring to the modified structure of the basic cross-section of the present invention configured as described above are as follows.

The bridge shown in Fig. 3 shows a one-chamber girder composite bridge with one box concrete 3, and is mainly used for bridges having a small distance (13 m or less).

The bridge shown in Fig. 4 shows a basic section of a two-mold type, showing a structure in which two girders 2 are connected by box concrete 3 in succession, and have a bridge having a width of 18 to 25 m in general. Mainly applies to

The bridge shown in Fig. 5 is a two-sided cross-sectional structure in which an intermediate girder 2 'is installed on one box concrete 3, and the bridge is mainly used for a bridge of 13 to 18 m, and in the two-sided cross-sectional structure, Abdominal concrete 3b is not installed on the upright beams of the intermediate girders 2 '. The two-threaded basic cross section is more stable compared to the two main cross section.

The bridge shown in FIG. 6 shows a basic section of a three columnar shape, showing a structure in which two girders 2 are connected by box concrete 3 in succession. This is usually applied to bridges with a width of more than 25m and is mainly used for socializing.

On the other hand, when the cross-sectional force of the lower flange is insufficient, as shown in Figure 7, the reinforcing material 6 is mounted to the lower flange (2b) of the portion that meets the upright beam of the steel girder (2), the reinforcing material (6) Box concrete (3) in which the lower flange (2b) included is installed to reinforce the cross-sectional force. Moreover, the abdominal concrete 3b provided in the upright beam of the said steel girder 2 has a structure in which the tendon 5 is not provided.

When the torsional rigidity of the box concrete cross section is insufficient, as shown in FIG. 8, the reinforcement 6 is mounted on the lower flange 2b of the site where the steel girder 2 meets the upright beam. Box concrete 3 having a lower flange 2b included therein is installed to reinforce the cross-sectional force. In addition, a torsion reinforcement member 7 is installed in the inner box space of the steel girder 2 in an X-shape to install the box concrete. The torsional rigidity of the box section is reinforced by supporting (3) and the steel girder (2).

If the cross-sectional force of the upper and lower flanges 2a and 2b of the steel girder 2 is not appropriate, as shown in FIG. 9, the cross-sectional force reinforcement continues over the entire length of the upper flange 2a of the steel girder 2 as shown in FIG. The steel plate 8 is provided to reinforce the cross-sectional force of the upper flange 2a. At this time, like the tendons 5 installed in the lower flange concrete 3a, the tendons 5 'are installed in the upper reinforcing slab 1 to facilitate load distribution. However, tendons 5 are not installed in the abdominal concrete 3b.

Meanwhile, modifications of the present invention will be described with reference to FIGS. 10 to 12.

In the modified example of the present invention, as shown in Fig. 10a, the upper surface of the upper flange (2a) of the steel girder (2) is provided with a sectional reinforcing steel sheet (8) continuous over the entire length, the lower flange (2b) A single reinforcement (9) is installed in each area where the beam meets the upper and lower flanges (2a, 2b) when there is a margin in the cross-sectional force of the upper, lower tension reinforcement, so the box concrete (3) tendon (5) The box girder structure is removed.

The preflex box girder composite type shown in FIG. 10B is composed of a single flange, not a steel plate, in which the lower flange 2b of the steel girder 2 is a continuous steel plate, and no tendons are added to the single lower flange 2b. It has a structure in which the box concrete 3 is provided.

The box girder of FIG. 11 is formed of a steel plate in which the upper flange 2a of the steel girder 2 is continuous, and the lower flange 2b is provided with a continuous steel plate over the entire length, and meets the upright beam of the steel girder. The reinforcing material 6 is provided in the lower flange 2b. In addition, in order to improve the internal workability, the concrete is poured into only the lower flange 2b of the steel girder 2 without installing abdominal concrete on the upright beam of the steel girder 2.

The structure of the box girder of FIG. 12 is a box girder installed at a section in which a parent bridge of a continuous bridge acts. Looking at the configuration thereof, the cross-sectional force that is continuous over the entire length of the upper flange 2a of the steel girder 2 is as follows. The reinforcing steel plate 8 is installed, and tendons 5 'are installed in the reinforced concrete slab 1. The lower flange 2b is formed of a single flange instead of a continuous steel plate, and a single lower flange 2b is provided with a reinforcing material 6 and a lower tendon 5 is not added to the lower flange concrete 3. This makes it easy to distribute the load in a continuous bridge.

On the other hand, in the box girder composite bridge structure of the present invention as described above, as the axial configuration of the upper or lower steel, as shown in Figure 13a to Figure 13d, respectively, using a steel sheet, a steel plate / frame, a steel sheet or a deck plate Can be installed economically.

That is, the steel girder 2 shown in FIG. 13A shows an example in which the lower flange 2b is made of one steel plate, which is most excellent in torsional rigidity and stability.

The steel girder 2 shown in FIG. 13B forms a through hole 11 at predetermined intervals in the longitudinal direction in the center of the lower flange 2b formed of steel sheet, and a steel frame or deck plate in the through passage 11. The example in which (12) is properly installed is shown.

The steel girder shown in FIG. 13C forms a through hole 11 in the longitudinal direction in the center portion of the lower flange 2b formed of steel sheet, and the steel frame or deck plate 12 is formed only in the center portion of the through hole 11. It shows an example of installation.

The steel girder shown in FIG. 13D is an example in which holes are formed in two central portions of the lower flange 2b formed of steel sheet, showing the most economical structure.

The structure of the steel girder shown in Figs. 13A to 13D is a structure that can sequentially reduce the manufacturing cost, these structures can be adapted to the appropriate bridge in consideration of economics and construction.

Next, the construction method of the present invention will be described.

First, as shown in FIG. 2a, the steel sheet 2b is attached to the lower portion of the T-shaped steel girder 2 to produce a box girder, and after the formwork is installed, the steel wire and the vinyl tube are placed at the lower flange concrete 3a placing position. Install tension material using the back. And camber management is performed.

After performing the step, as shown in Figure 2b by using a hydraulic device or the like to load the preflex load on the steel girder, the concrete is poured into the formwork to steam curing. At this time, the safety load and deformation of the buckling are measured, and the steam curing temperature is managed.

After the step, after removing the preflex load as shown in FIG. 2C, the introduced concrete stress is examined, and as shown in FIG. 2D, the work is tensioned by using a tension member pre-installed in the concrete placing process in the formwork. Manage tension after doing this.

Next, as shown in FIG. 2E, the reinforcement box girder composite bridge is completed by placing the concrete after placing the upper reinforcing bar, and performing abdominal concrete quality control.

Figure 2f shows a live load on the composite bridge completed construction.

The present invention described above is not limited to the above-described embodiments and drawings, and various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be apparent to those who have

As described above, according to the present invention, the steel beams synthesized in the concrete slab in the steel composite continuous bridge has a box structure to increase longitudinal, transverse bending stiffness and torsional stiffness compared to conventional girder bridges, Compared with steel, it is economical for PC box girder bridge.

In addition to the increase in the torsional rigidity of the box structure, the stability and wind resistance / shockproof stability due to the increase in the bending / lateral stiffness are increased, thereby improving the performance and durability of the bridge. In addition, the energy saving due to the vertical upward force of the preflex type bridge and the cracking are controlled by tensioning within the allowable stress of the concrete slab by the steel and the tensioning material by the welding of high strength bolts and the tensioning material at the connection site of the continuous bridge. It has the effect of increasing the connection effect by the composite effect of the concrete part.

Claims (17)

Reinforced concrete slabs with a predetermined width; It is installed and supported every predetermined span of the slab, the upper flange is synthesized in each of the slab span, at least one of the upper and lower flanges is formed of one of the continuous steel frame or steel sheet to form a box shape, One or more steel girders loaded with a vertical or downward preflex load on the steel frying or steel sheet; And Box concrete is installed on the lower flange of the steel girder to support the steel girder Leafrest box girder composite bridge comprising a. The method of claim 1, The lower flange concrete is installed in a predetermined thickness on the lower flange of the steel girder is further included, the lower flange is characterized in that the restraint box girder composite bridge is further prestressed in the axial direction. The method of claim 2, Leafless, characterized in that the lower flange concrete thickness is 20 ~ 40cm Trestle box girder composite bridge. The method of claim 1, And the box-shaped steel girder is continuously installed to have a predetermined number of molds in the bridge width. The method of claim 1, And at least one intermediate girder is provided for dividing the inside of the box-shaped steel girder so as to have a predetermined number of actual shapes. The method according to any one of claims 1 to 5, The box concrete further comprises a plurality of tendons installed to apply prestress therein. The method according to any one of claims 1 to 5, And a reinforcing box girder composite bridge further comprising a reinforcing member installed at an upper portion thereof to reinforce the cross-sectional force of the lower flange of the steel girder. The method of claim 7, wherein And a reinforcing box girder composite bridge further comprising a reinforcing member installed in an inner space of the box section to reinforce the torsional rigidity of the steel girder. The method of claim 1, Leafrest box girder composite bridge further comprising a continuous steel plate continuously installed on the upper flange of the steel girder to increase its cross-sectional force The method of claim 9, A leafrest box girder composite bridge further comprising tendons embedded in the slab and the box concrete. The method of claim 1, The upper flange of the steel girder is formed of a continuous steel plate, the box restraint box girder composite bridge, characterized in that the box concrete is poured only on the lower flange of the steel girder to improve the internal workability. The method of claim 1, Reinforced box girder composite bridge, characterized in that the abdominal concrete of a predetermined thickness is further placed on the inner circumferential surface of the steel girders. The method of claim 1, And a through-hole formed in the center of the lower flange of the steel girder at predetermined intervals in the longitudinal direction. The method of claim 13, A composite leaf restraint box girder bridge in which any one of a steel frame and a deck plate is installed at predetermined portions of the plurality of through holes formed in the lower flange. The method of claim 13, A composite leaf restraint box girder bridge in which any one of a steel frame and a deck plate is installed at a central portion of a plurality of through holes formed in the lower flange. The method of claim 1, And at least one portion of the upper or lower concrete of the steel girder is prestressed by an external preflex load. Reinforced concrete slabs with a predetermined width; One or more steel girders installed and supported at predetermined intervals of the slab, the upper flanges of which are synthesized in the respective slab spans, and having a single reinforcement installed on the lower flanges to form a box shape; Sectional force reinforcing plate continuously installed on the upper flange of the steel girder; A tendon installed to prestress the slab; And Box concrete which is installed over the upright beam and the lower flange of the steel girder to support the steel girder Leafrest box girder composite bridge comprising a.