KR100561034B1 - Connecting method for segmental prestressed preflex steel composite beam - Google Patents

Abstract

According to the present invention, the prestressed preflex steel composite beam with the segmented block out is manufactured in the factory, and then integrated at the site, but the secondary prestress is introduced into the steel composite beam lower flange concrete at the time of fixing the tension member, and at the same time, the compressive force is introduced into the segmented portion. The present invention relates to a method for integrating a segmented prestressed preplex rigid composite beam, which can be more reliably integrated. Integrating the prestressed preflex steel composite beam segmented by the present invention in the field can minimize the field work, thereby saving the work air and construction cost, and the difficulty of securing the production place for the production of the steel composite beam between long diameters. It is possible to solve the problem, so it is possible to construct a very economical bridge.

Composite Beam, Segmented, Secondary Prestressing

Description

Connecting method for segmental prestressed preflex steel composite beam}

Figure 1a is a side view and a front view of the I-shaped steel integrated by mechanically connecting (bolt, welding) of the three-segmented steel (I-shaped steel) of the present invention,

Figure 1b is a side view and a front view showing a state in which the pre-flection load (Pf) is applied to the three-segment I-shaped steel,

Figure 1c is a state in which the pre-flection load is applied to the three-segment I-type steel, the tension member is placed in the intermediate steel, and the lower flange concrete is poured and cured after excluding the segment of the type 1 steel. Shown in side and front views,

FIG. 1D shows a side view and a front view showing a state in which the composite beam, in which the primary prestress is introduced, is introduced to the site by removing (releasing) the preflection load Pf.

FIG. 1E illustrates a side view and a front view of a state in which the segmented rigid composite beam is brought into the field and assembled again (bolt or welded) to be integrated;

Figure 1f is a side view and a front view showing a state in which the integrated rigid composite beam is mounted on the bridge lower structure, the upper slab is poured, cured, and the lower flange concrete is connected.

Figure 2a is a side view and a front view showing a state in which the secondary prestress is introduced to the rigid composite beam by tensioning and fixing using a fixing device provided on both ends of the rigid composite beam.

FIG. 2B is a side view and a front view of a state in which an additional tension member is tensioned in the fixing device at both ends of the steel composite beam and additional secondary prestress is introduced in the steel composite beam in FIG.

FIG. 2C illustrates a side view and a front view of the steel composite beam in which the lower flange concrete, except for the segmented portion, is poured and cured in a state in which no tension member is disposed in the intermediate steel as compared to FIG.

2D, 2E, 2F, 2G, 2H, 2I and 2J show side and front views of an example of installing a tension member for introducing secondary prestress to the rigid composite beam of FIG. 2C.

3A, 3B, 3C, 3D, 3E, 3F, 3G, and 3H show side and front views of various installation examples of the fixing device and the tension member of the present invention.

<Explanation of main code of drawing>

100: I type steel 200: Tensile material (including non-bonded PC strand)

300: lower flange concrete 400: steel composite beam

500: bridge upper structure concrete 600: fixing device

The present invention relates to a method of integrating a segmented prestressed preflex rigid composite beam. More specifically, the present invention relates to a method of integrating a segmented prestressed preflex steel composite beam, which is conventionally manufactured after the production of one pre-segmented prestressed preflex steel composite beam in a factory, and then segmented into a site to be integrated again. When the secondary prestress is introduced by the tension member, the secondary prestress is introduced to the lower flange concrete of the steel composite beam, and the compressive force is also introduced to the segment portion, so that the lower flange concrete of the segment portion is reliably integrated. The present invention relates to a method for integrating a prestressed preflex rigid composite beam.

The conventional Preflex Steel Composite Beam related to the present invention is a bridge beam developed in Belgium in the early 1950s, and has a constant load on a type I steel (I type girder) made of high tensile steel sheet or the like. Pf load) to generate the design maximum bending moment in advance, and in the state accompanied with deflection deformation, remove the load (Pf load) previously loaded after placing and curing concrete of a certain section on the lower flange. Compression prestress was introduced into the lower flange concrete in the process of restoring the accompanying deflection deformation, and the mold height was considerably lower than any other bridge construction method such as a PC beam (prestress concrete beam) bridge under constant interval and design load conditions. It has been used in bridge construction because of its advantages such as being able to promote efficient use of it.

However, when the preflex rigid composite beam is designed in a completely prestressing manner for the purpose of not allowing cracking of the lower flange concrete without any other means, the preflex rigid composite beam has a cross section at a constant interval and load conditions. As they become larger and higher in shape, they lose all of the fundamental advantages of the preflex steel composite beam, which inevitably has to be designed and constructed with partial prestressing.

In the case of following the partial prestressing design method, in order to adhere to the fundamental advantage of maintaining a low profile of the prestressed compressive stress introduced into the lower flange concrete, the limited height of the I-shaped steel and thus the limited deflection and return deformation Since it is designed and constructed on the basis of size, a large tensile stress (a large tensile stress that cannot be considered even when designing by partial prestressing) is inevitably generated in the lower flange concrete.

Therefore, adopting the design method by the partial prestressing method and generating excessive tensile stress in the lower flange concrete eventually leads to excessive tensile cracking and deflection of the lower flange concrete, which inevitably causes serious effects on the durability of the steel composite beam. .

Therefore, it is designed and manufactured with full prestressing while maintaining the low profile, which is the advantage of the conventional preflex steel composite beam, and maintaining the economical efficiency, thereby reducing the tensile cracking of the lower flange concrete, resulting in excessive sagging and rapid decrease in fatigue strength. A prestressed preflex composite beam has been developed to prevent

In order to cope with the magnitude of the crack generation moment in the lower flange concrete in the cross section of the conventional preflex rigid composite beam, the lower flange concrete is removed by removing the predetermined load (Pf load) previously loaded after the lower flange concrete curing is finished. After the primary prestress was introduced (after release) into the lower flange concrete, the tension member (non-bonded PC strand) pre-arranged in the lower flange concrete was tensioned and fixed as a fixing device to introduce additional secondary prestress to the lower flange concrete. By increasing the resistance moment inside the composite beam, the design of the composite beam can be designed in a full prestressing manner in which the tensile stress does not occur at all on the lower flange concrete while maintaining the shape of the existing composite beam. .

However, in case of long span, prestressed preflex steel composite beam is connected to a large number of I-type steels in a factory in one factory, and is fabricated and installed in the field as a prestressed preflex steel composite beam that forms one span. Since it requires a large production site near the location of the steel composite beam construction site, a large number of steel composite beam manufacturing equipment should be put in the field, and the one-off material among the input equipment is considerable, which acts as an increase factor of air and construction cost. The necessity of improving the efficiency of prestressed preflex steel composite beams has been raised.

SUMMARY OF THE INVENTION An object of the present invention is to provide a simple bridge or continuous bridge by efficiently introducing secondary prestress into the lower flange concrete not only at the segment but also throughout the composite beam in the field integration work of the segmented prestressed preflex steel composite beam. It is possible to solve the difficulty of securing the production place for the production of the long-span steel composite beam in the bridge construction using the pre-presisted preflex steel composite beam, and to save the bridge construction air and the construction cost by minimizing the effort in the field. It is to provide a way to improve the quality through factory production.

The present invention, in order to achieve the above technical problem, by integrating the I-type steel divided into several segments into one and then applying the preloading load, pour the lower flange concrete to the entire I-type steel except for the segmented portion, After removing the pre-loading load, the steel composite beam in which primary prestress is introduced into the lower flange concrete is manufactured at a factory (or near the site), and the manufactured steel composite beam is separated into several segments, and then the transport vehicle is Bringing it to the site by using it, the composite steel beam is connected to one composite steel beam and integrated.

In this case, the I-type steel formed in the composite beam is integrated by bolting or welding, and in the case of the lower flange concrete including the segmented part, the lower flange concrete is continuously filled by placing concrete (including expanded concrete) or epoxy resin in the segmented part. And the lower flange concrete near both ends of the composite beam (including non-adhesive PC strands), which is pre-positioned at the time of manufacturing at the factory, inside the lower flange concrete of the composite beam formed in the middle of the composite beam. By tensioning or fixing the upper or lower portion, the secondary prestress is introduced not only in the segment portion but also throughout the lower flange concrete, so that the segmented rigid composite beam is efficiently integrated. The factory manufactured steel composite beam is not formed on the flange concrete. After integrating at the lower flange concrete, the tension material may be integrated by installing a tension member to the upper or lower portion of the lower flange concrete exterior or by installing a tension member to cross from the lower flange concrete to the upper, and the method may be appropriately integrated. The bottom flange concrete can be used in combination.)

Accordingly, with reference to the accompanying drawings, the most preferred embodiment which can be easily carried out by the person skilled in the art the method of integrating the segmented prestressed preflex steel composite beam according to the characteristics of the present invention. I explain in detail

The method of integrating the segmented prestressed preflex rigid composite beam of the present invention

Assembling the segmented steel (100a, 100b, 100c) at the factory and then applying a prefraction load (Pf); The tension member 200 is installed to be embedded in the casing concrete around the lower flange of the at least one intermediate steel member 100b except for the segmented steel members 110a and 100c at both ends, or the tension member is not formed in the lower flange concrete in advance. In the non-state state, after forming the lower flange concrete (300a, 300b, 300c) in the steel except for the segment (A) to remove the preflection load to produce a steel composite beam 400 in which the primary prestress is introduced ; Bringing the segmented rigid composite beams (400a, 400b, 400c) into the site and assembling them to form the bridge upper structure concrete and connect the segments; And tensioning the tension member in the rigid composite beam to introduce secondary prestress into the rigid composite beam 400.

Figure 1a shows a side view and a front view of the integrated I-type steel by mechanically connecting (bolt, welding, etc.) of the three-segmented steel (I-type steel) of the present invention.

In factories (or near-site workshops), Type I steels are manufactured to standard lengths and then segmented to be suitable for transport. Although three-segmentation is common, it may be segmented into three or more segments if a long I-shaped steel is required to produce a long composite beam over long spans.

In the present invention, the I-type steel is divided into segmented end steels (100a, 100c) and the middle steel (100b). (All the middle steel except the end steel is regarded as intermediate steel regardless of the number.) The upper and lower flanges can also be manufactured using overlapping plates. This is because in the case of the intermediate steel, since it is the site receiving the most bending moment due to external load, it is preferable to manufacture the upper flange and the lower flange thickly using the overlap plate, which is a kind of reinforcement material, in order to increase the rigidity.

Furthermore, it is preferable to avoid the place where the bending moment acts as large as possible, and the segmented I-type steels are connected to each other by using a mechanical connection device such as bolts and welding. This completes the integrated I-shaped steel 100.

Figure 1b is a side view and a front view showing a state in which the pre-flection load (Pf) is applied to the integrated three-piece I-shaped steel 100.

This is to introduce the prestress to the lower flange concrete, except for the segment, which is described later by using the elastic restoring force of the I-type steel when the preflection load is removed, and its size, loading position, and load recovery are designed for the composite beam. Various changes may be made depending on requirements.

FIG. 1C shows the lower flange concrete 300a in which the tension member 200 is disposed in the intermediate steel 100b in a state in which the pre-flection load is applied to the integrated I-type steel 100 and the segment A of the I-type steel is excluded. , 300b and 300c are placed and cured and the preflection load is removed to show the side and front views of the steel composite beam in which the primary prestress is introduced into the lower flange concrete.

That is, a plurality of tension members (including 200, non-bonded PC strands) are installed around the lower flange of the intermediate steel 100b of the I-shaped steel 100, which is slightly curved due to the preflection load, and the intermediate steel to be poured later. After installation so as to protrude above the end of the lower flange concrete of the composite beam, the concrete is poured and cured in the lower flange of the both ends (300a, 300c) and the intermediate (300b) except for the segment (A) of the I-type steel Lower flange concrete (300a, 300b, 300c) is formed on each of the segmented I-type steel.

When the preflection load is removed, the I-type steel is restored to its original shape by the elastic restoring force of the I-type steel, and the first prestress is introduced into the lower flange concretes 300a, 300b, and 300c. This completes the fabrication of the integrated composite steel beam 400.

Figure 2c is the both ends of the steel (300a, 300c) except for the segment (A) of the I-type steel in the state that no separate tension member 200 is installed in each lower flange concrete (300a, 300b, 300c) of the I-type steel And in the lower flange of the intermediate steel (300b) is shown in a side view and a front view of the integrated steel composite beam 400 in the concrete, the curing state, which is not installed in advance in the intermediate steel, the tension member 200, FIG. 2d, 2e, 2f, 2g, 2h, 2i and 2j is used in the steel composite beam 400 that can be applied when the tension member 200 is installed outside the lower flange concrete.

In other words, there is a difference in the method of fabricating the steel composite beam produced in the factory according to the difference in the method of introducing the second prestress to the lower flange concrete, the segmented steel composite without the pre-installed tensile material in the field After assembling the beam, a tension member is provided on the upper and lower portions of the lower flange concrete at both ends of the rigid composite beam, and is a rigid synthetic beam used when the tension member is fixed after tension using the fixing device provided at both ends.

FIG. 1D is a side view and a front view illustrating a state in which the steel composite beam 400 in which primary prestress is introduced is segmented (separated).

If the mechanical connection (bolt, welding, etc.) of the segment A of the I-type steel that mechanically connects the integrated steel composite beam 400 to each other is removed, the three steel composite beams 400a, 400b and 400c are segmented. This is ready. At this time, the end of the tension member 200 has a merit that it can be rolled up round and very easy to handle.

The process of Figure 1a to 1d is made in the factory, thereby having the advantage of easy quality control in the production of a composite beam, it is possible to prevent the increase of work air and construction costs by the work site composition In addition, it is possible to prevent an increase in construction costs due to installation and dismantling of on-site facilities.

FIG. 1E illustrates a state in which the segmented rigid composite beams 400a, 400b, and 400c are brought back into the field and assembled (bolt or welded), and a side view and a front view thereof, and FIG. 1F illustrates the assembled rigid composite beams 400a. , 400b, 400c) mounted on the bridge undercarriage, such as bridges and shifts, and pour the upper slab 510, the abdominal concrete 520 and the bridge superstructure concrete 500, such as crossbeams, curing, and lower flange concrete ( A side view and a front view show a state in which 300a, 300b, and 300c are connected to each other.

The steel composite beam 400, which is installed on the pedestal of the site and assembled by bolts or welding again, is mounted on the lower structure of bridges such as shifts and piers using a lifting device, and then the upper slab concrete and the abdominal concrete for the steel composite beam And the bridge upper structure concrete 500 including a cross beam and the like is poured and cured. That is, the work of integrating the steel composite beam with the upper structure of the bridge proceeds.

At this time, the I-type steel forming the steel composite beam 400 can be easily integrated by bolt bonding or welding, but the lower flange concrete surrounding the I-type steel is not easy to integrate, so the lower flange concrete is efficiently There is a need for a method for integral connection.

First of all, when the factory is manufactured, concrete and mortar are poured into the segment with the steel composite beam located on both sides of the steel composite beam in which the tension member (including the non-bonded PC strand) is disposed inside the lower flange concrete, Connect each lower flange concrete to each other.

In this case, the secondary prestress, which can prevent the tensile cracking of the lower flange concrete due to the secondary external load such as the live load, is before the state is introduced into each lower flange concrete, the introduction of the secondary prestress is 3 In one embodiment are presented.

FIG. 2A illustrates the first embodiment, in which both ends of the tension member are extended by unrolling the rounded tension member 200 exposed to the lower flange concrete of the intermediate composite beam 400 b. Figure 2 illustrates a case where the secondary prestress is introduced into the lower flange concrete 300 by being fixed after fixing to the fixing device 600 installed on both outer ends or the lower flange concrete upper surface of the steel composite beam in the extended state. At this time, the secondary prestress is introduced to the lower flange concrete of the steel composite beam, and the compressive force can be introduced to the segmented portion, so that the lower flange concrete of the segmented portion can be reliably integrated, and the secondary prestress equivalent to the batch fabrication is made of the rigid composite beam. It can be introduced in.

At this time, it is preferable to tension and fix the tension member after placing the slab and the connecting part, because it is structurally advantageous to the connecting part and the steel composite beam. It is also possible to connect the lower flange concrete before and tension and settle the tension member.

Figure 2b shows a second embodiment as shown in Figure 2a to introduce a second prestress, additionally showing the case where the tension member 200 is further installed in the fixing device 600 installed outside the rigid composite beam and tensioned and fixed In this way, it can be seen that the secondary synthetic prestress can be introduced into the composite synthetic beam in a timely manner, at an introduction amount, or at a different time.

FIG. 2D illustrates a third embodiment. Unlike the composite beam 400 of FIG. 1C, unlike the composite beam 400 of FIG. 1C, the secondary prestress is applied to the composite beam when the tension member is not included in the lower flange concrete. As an example of introducing the tension member 200, the tension member 200 is installed in the fixing device 600 installed on the lower flange concrete at both outer ends of the steel composite beam, and then fixed after tension.

2e is a case where the fixing device is different from FIG. 2d after the tension member 200 is installed in the fixing device 600 installed under the lower flange concrete of the steel composite beam, and then fixed after tension.

FIG. 2F illustrates a case where the tension member 200 is tensioned and fixed to the fixing device 600 installed on the upper and lower lower flange concretes of the outer both ends of the composite beam in parallel with the tension members of FIGS. 2D and 2E.

Figure 2g is a tension material redirection device (610, a kind of saddle) is installed in the lower flange concrete lower portion of the intermediate rigid composite beam (400b) connected and the fixing device is installed on the upper upper flange of the lower flange of both ends of the composite beam In the case, the tension member 200 is installed in the fixing device 600 at both ends via the tension member redirection device and fixed after tension.

FIG. 2h illustrates a case where the tension member 200 is tensioned and fixed to the fixing device 600 installed on the upper and lower lower flange concrete portions of the outer both ends of the composite beam in parallel with the tension member 200 of FIGS. 2d and 2g. will be.

FIG. 2i illustrates a case in which a tension redirection device 610 (a kind of saddle) is installed on the lower flange concrete and the lower flange concrete of the connected intermediate rigid beam 400b, and the fixing device is installed on the lower flange concrete at both ends of the external composite beam. In this case, the tension member 200 is installed in the fixing device 600 at both ends via the tension member redirection device 610 and is fixed after tension.

FIG. 2J shows the tensioner redirection device 610 (a kind of saddle) and the outer both ends of the steel composite beam installed in the lower flange concrete upper and lower portions of the intermediate steel composite beam 400b in parallel with the tension member 200 of FIGS. 2D and 2I. The case where the tension member 200 is fixed after the tension member 200 is fixed by using the fixing device 600 installed on the upper portion of the lower flange concrete is illustrated.

3A-3H show a fixing device 600 used to introduce secondary prestress into the rigid composite beam of FIGS. 2A, 2B, 2D, 2E, 2F, 2G, 2H, 2I, and 2J. ) Shows a specific example according to the installation position,

3a illustrates a case in which the fixing device 600 of the protruding formulation is installed on the upper portion of the lower flange concrete at the outer both ends of the composite beam.

In the case of FIG. 3B, the fixing device 600 of the protruding formulation is installed on the upper side of the lower flange concrete of both the outer ends and the middle of the steel composite beam (which may be fixed after the tension member is re-tensioned in the intermediate protrusion 610). Shown,

3c illustrates a case in which a protruding rectangular fixing device 600 is installed on upper portions of lower flange concretes at both ends of the external composite beam, and a tension member is embedded in a tube such as a sheath tube between the fixing devices.

In the case of Fig. 3d, the horizontal beams at both ends are used as the fixing device 600, and a tension member is embedded in a tube such as a sheath tube between the fixing devices.

3e illustrates a case in which the horizontal beams at both ends are used as the fixing device 600, and additional fixing protrusions are used immediately inside the horizontal beams.

3f illustrates a case in which the horizontal beams at both ends are used as the fixing device 600, and an intermediate protrusion 610 is additionally used right inside the horizontal beam and the upper middle of the lower flange concrete.

3G illustrates a case in which horizontal beams (tapered) at both ends are used as the fixing device 600,

3H illustrates a case in which horizontal beams (tapered) at both ends are used as the fixing device 600, but two middle projections 610 are additionally used in the upper middle of the lower flange concrete.

As such, the secondary prestress can be applied only to the center portion of the span which is subjected to a large stress by controlling the installation position of the fixing device of the tension member, thereby achieving structural and material efficiency.

The prestressed preflex steel composite beam, which was previously manufactured in the field, was segmented and manufactured at the factory, and a method for effectively integrating the segmented steel composite beam by applying secondary prestress using a tension member in the field was provided. It is possible to solve the difficulty of securing the production place for the production of steel composite beams, to minimize the effort in the field, to save air and construction cost, to improve the quality through the factory production, and to apply the secondary prestress. Positioning provides an efficient method of introducing secondary prestresses. In other words, the secondary prestress can be applied only to the middle section of the span that is subjected to high stress by adjusting the installation position of the fixing device of the tension member. have.

Claims (8)

Assembling the segmented steel in the factory and applying a preflection load; Primary prestress was introduced by removing the preflection load after forming the lower flange concrete in the steel except for the segmented portion while the tension member was installed around the lower flange of at least one intermediate steel except for the segmented steel at both ends. Manufacturing a rigid composite beam; Bringing the segmented rigid composite beam into the field and assembling the bridge to form the bridge upper structure concrete and connect the segmented portion; And The tension member is tensioned and fixed in the rigid composite beam to introduce the secondary prestress into the lower flange concrete, and the anchoring member is fixed to both ends of the tension member in the fixing device installed in the middle, including both external ends or both ends of the rigid composite beam. A method of integrating a segmented prestressed preplex rigid composite beam comprising: a step of fixing after tensioning. The non-bonded PC strand according to claim 1, wherein the tension member is a non-bonded PC strand, wherein the non-bonded PC strand installed in the segmented rigid composite beam having the intermediate steel is rolled round with both ends exposed to the outside of the lower flange concrete. A method of integrating a segmented prestressed preflex steel composite beam, characterized in that: delete The rigid composite beam according to claim 1, further comprising a tension member, which is any one of a bonded tendon, a non-bonded tendon, and an unbonded strand, is further tensioned and fixed to a fixing apparatus provided at both ends of the rigid composite beam. A method of incorporating a segmented prestressed preflex steel composite beam further comprising: Assembling the segmented steel in the factory and applying a preflection load; Forming a lower flange concrete in the steel except for the segmented portion, and then removing the preflection load to produce a steel composite beam in which primary prestress is introduced; Bringing the segmented rigid composite beam into the field and assembling the bridge to form the bridge upper structure concrete and connect the segmented portion; Tensile material, which is one of bonded tendons, non-bonded tendons, and non-bonded strands, is tensioned and fixed in the rigid composite beam to introduce secondary prestress into the lower flange concrete, wherein the fixing of the tensile member is performed at both ends or both ends of the outer composite beam. A step of tensioning and fixing the tension member, which is any one of a bonded tendon, a non-bonded tendon, and a non-bonded strand, in a plurality of fixing apparatuses installed in the middle of the segmented prestressed preflex composite beam; Integration method. delete The method of claim 6, wherein the fixing device Method 1 installed on at least one of the upper surface and the lower surface of the lower flange concrete; Method 2 installed across the lower flange concrete upper surface and the lower surface; And The method of claim 1, wherein the method 1 and the method 2 are installed in one of a combination method. The segmented prestressed preplex according to claim 1 or 5, wherein the segmented portion is formed by placing or filling any one of concrete, mortar, and epoxy resin including expanded concrete in the segmented portion. Method of integrating steel composite beams.

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