KR101337330B1 - Psc beam with optimized web, manufacturing method and bridge construction method using the same - Google Patents

Abstract

The present invention relates to a prestressed concrete (PSC) I-beam which is cost-efficient by having an optimized web, the maximized confinement of a lower flange, and maximized cross-sectional efficiency; a manufacturing method for the same; and a bridge construction method using the same. The PSC I-beam includes one part which is extended from the end of the beam and has a narrowest where a tendon passes through; and the other part which is extended from one part and has a narrower web than the narrowest web of one part where the lower flange is arranged.

Description

PSC beam with optimized abdominal cross section, fabrication method and bridge construction method using the same {PSC BEAM WITH OPTIMIZED WEB, MANUFACTURING METHOD AND BRIDGE CONSTRUCTION METHOD USING THE SAME}

The present invention relates to a PSC beam with optimized abdominal cross section, a fabrication method thereof, and a bridge construction method using the same. More specifically, the present invention relates to a more economical PSC beam that maximizes the cross-sectional efficiency of the PSC beam by optimizing the abdominal cross section of the PSC beam of the I-type cross section and maximizing the confinement effect of the lower flange, and a method of fabricating the same and a bridge construction method using the same. .

In general, recently constructed concrete bridges are constructed using prestressed concrete beams (hereinafter referred to simply as "PSC beams"). In the bridge construction method as described above, after manufacturing the PSC beam on the ground, and transported to the construction site to mount both ends of the PSC beam 10 on the alternating or pier 30 as shown in Figure 1a, and then cross beam (not shown) It is a method of forming and constructing bridges by laying slab concrete and constructing floor plates 20 (slabs).

Conventionally, the conventional PSC beam 10 required for the above method is manufactured to extend along the axial direction while maintaining an I-shaped cross section.

Looking at the manufacturing process of the PSC beam 10, after installing the reinforcing bar assembly and the tension member (PC steel strand 50) as shown in Figure 1b in the formwork installed on the workbench, the concrete is placed and cured in the formwork, and the formwork is dismantled. To produce the PSC beam 10.

In this case, it can be seen that the tension member 50 is arranged in a parabolic form based on the center portion as shown in FIG. 1B over the entire length of the PSC beam 10.

Since the size of the bending moment due to the load is not large at both ends of the PSC beam 10, and the manufacturing method by the post tension method is required, a space for installing the fixing device 40 is required, as shown in FIG. 1A. It can be seen that both ends of the) to be formed in the shape of a rectangular sphere (square box).

However, in the case of manufacturing the PSC beam 10 by the pretension method, even if the tension member is arranged in a straight or inclined section-linear section-slope section through both ends and the center portion, the fixing device is installed at both ends of the PSC beam 10. Since there is no need, both ends of the PSC beam 10 may be formed in the shape of a square sphere (square box), but it may be seen that the square sphere is formed in a small cross section in comparison with FIG. 1C.

Thus, when the pretension type PSC beam 10 has the same cross-sectional stiffness, it can be manufactured slimmer compared to the post tension PSC beam 10, and the aesthetics can be enhanced and the self-weight can be reduced. There is an advantage.

However, the pretension method has a disadvantage in that a separate dedicated manufacturing facility is separately required, and thus, in practice, the post tension PSC beam 10 is frequently used.

Therefore, if the cross-section stiffness can be secured to the maximum in the PSC beam 10 while the cross-sectional efficiency can be increased, more economical manufacturing of the PSC beam 10 and a bridge construction using the same can be seen.

Accordingly, the present invention is more economical PSC beam production and bridge construction method by securing a sufficient cross-sectional stiffness while having a more efficient abdominal cross-section regardless of the tension material and fixing device in the pre-tension or post-tension PSC girder The task is to solve the provision.

The present invention to achieve the above technical problem

First, the change of the abdominal cross-section in the PSC beam of I-type cross-section cancels out the effect of the change of the self-weight and the change of the cross-sectional stiffness. To make sure that the width of the abdomen can be structurally reduced to the maximum,

Second, the width of the abdomen should be minimized in the section where the tension member is installed (end and general section), so the width of the abdomen should be minimized in the section where the tension member passes through the abdomen (regular section) in the PSC beam. In the section where the tension material does not pass through the abdomen (abdominal cross section minimization section), the width of the abdomen is smaller than the width of the abdomen to be secured as described above. Thus, in the present invention, the abdomen is formed in the shape of the cross section at the connection between the end section and the general section and the connection section between the general section and the abdominal section minimization section.

Third, if the width of the abdomen is minimized in the form of a cross section, the self-weight of the PSC beam may be reduced while buckling may occur in the abdomen where the width is reduced. Therefore, the present invention is to install a reinforcement for preventing abdominal buckling to prevent the abdominal buckling in addition to the horizontal beam installation finishing portion.

Thus, the abdominal buckling reinforcement is intended to reinforce the abdomen, unlike the horizontal beam installation finish is to be limited to only the outer side of the abdomen.

Fourth, the tension material of the PSC beam is disposed only in the lower flange in the section where the tension material does not pass through the abdomen (abdominal cross section minimization section). As a result of the compression prestress caused by tension and fixation of the tension member, the lower portion of the neutral axis of the PSC beam receives the compressive stress. If the magnitude of such compressive stress can be increased in the same cross-sectional size, the cross-sectional stiffness of the PSC beam according to the present invention becomes even more effective even if the width of the abdomen is reduced to the cross-sectional shape.

Accordingly, the present invention is to reinforce the lateral restrained reinforcing bar closed by wrapping the tension member in the section to surround the tension member disposed on the lower flange to have the effect of restraining the lower flange of the lower neutral shaft.

As a result, the present invention allows to reduce the self-weight of the PSC beam, thereby maximizing the cross-sectional efficiency of the PSC beam by improving the concrete compressive resistance ability by the confine effect of the neutral axis lower.

To this end,

A PSC beam having an end section L1, a general section L2, and an abdominal cross section minimization section L3, divided according to the tension member arrangement form over the entire extension length (L = L1 + L2 + L3),

The end section L1 is a section in which fixing devices are installed on both end faces of the PSC beam 100, and the tension member is formed in a rectangular sphere shape in order to secure a fixing device installation space through the abdomen throughout the cross section. ,

The general section (L2) is a section that is continuous with the end section (L1) is formed in the cross section through the tension material in the abdomen having a minimum width (b),

The abdominal cross-sectional minimization section L3 is a section continuous with the general section L2 and has an abdominal width b1, b> b1 smaller than the minimum width b of the abdomen, and a tension member is disposed only on the lower flange of the PSC beam. Formed in cross section,

The minimum width (b) of the abdomen is a concrete covering, the diameter of the reinforcing bar, the minimum abdomen width that can be installed in the tension material, the end section (L1) and the normal section (L2) and the normal section (L2) and the abdominal cross-section minimum section ( The connecting part of L3) is formed so that the width of the abdomen is different from each other to form a cross section,

In the abdominal cross-sectional minimization section, a tension member is disposed only on the lower flange of the PSC beam, and the abdominal cross section is arranged to relieve a plurality of transverse restrained bars that are closed to surround the disposed tension member in the longitudinal direction of the abdominal cross-section (L3) to reinforce the PSC beam in the longitudinal direction. To provide an optimized PSC beam, a fabrication method thereof, and a bridge construction method using the same.

Also preferably,

The abdomen buckling reinforcement is further formed on the PSC beam abdomen of the abdominal cross section minimization section (L3), and the abdominal buckling reinforcement is installed to prevent buckling of the abdomen separately from the crossbeam finishing part for installing the crossbeam. The present invention provides an optimized PSC beam to be formed only at both sides of the abdomen, and a fabrication method thereof and a bridge construction method using the same.

According to the present invention by optimizing the cross section of the PSC beam it is possible to provide a PSC beam having a cross-sectional force that can effectively respond to the member force. In addition, it is possible to prevent the buckling of the PSC beam by optimizing the abdominal width and to maximize the effect of prestress introduced by the efficient placement of the tension material.

1A is a constructional view of a conventional PSC beam,
Figure 1b is a layout of the tension material of the conventional PSC beam,
Figure 1c is a cross-sectional view and cut perspective view of a conventional PSC beam,
Figure 2a is a perspective view of a PSC beam configuration optimized the abdominal cross section of the present invention,
2B is a cross-sectional view of FIG. 2A of the present invention;
Figure 2c is a partial cross-sectional view of the PSC beam optimizing the abdominal cross section of the present invention,
3A and 3B are front and cross-sectional views of the PSC beam with optimized abdominal cross section,
Figure 3c is a rear view of the conventional transverse restraint bar.
4 is a perspective view of a bridge constructed using a PSC beam with optimized abdominal cross section of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

PSC Beam Construction Diagram Optimizing Abdominal Section of the Present Invention

First, assuming that the cross section of the PSC beam is a rectangular cross section whose height (h) and width (b) are defined, and that the same cross section is constant over the entire length,

When a load (P, tension force) is applied to such a PSC beam, the stress acting on an arbitrary cross section (A = b × h) is as follows.

(1)

(One)

Where +: compressive stress,-: tensile stress

f: stress (bending stress)

P: tension

A: Cross-sectional area

e: eccentric distance of P with respect to the neutral axis

I: Cross Section Second Moment

y: maximum cross-sectional distance from neutral axis (h / 2)

M: bending moment due to vertical load

If the above formula (1) is summarized based on the following formula (2),

(2)

(2)

이 되고

Become this

In summary,

(3)

(3)

             ① ②

.

That is, looking at the term ② for the stress introduced by the PSC beam self-weight of equation (3), it can be confirmed that the width b does not affect the stress change due to the increase in the cross-sectional stiffness of the beam.

In addition, looking at ① for the stress introduced into the beam by the tension force in the equation (3), it can be seen that as the width b increases, the stress introduced is rather reduced.

After all, in the above ① and ②

It can be seen that the increase of the width b increases the magnetic weight of the beam, but does not affect the stress introduced by the increase in the magnetic weight and the cross-sectional stiffness, but rather reduces the stress introduced by the tension member.

Therefore, the smaller the width b in the rectangular cross-section is, the more the stress introduced by the tension force increases. Therefore, in the I-shaped PSC girder, the minimization of the abdomen (web) has the same effect as increasing the cross-sectional stiffness of the PSC beam. Able to know.

In consideration of the various cross-sectional shapes of the PSC beam, there may be limitations (eg, the width of the upper flange cannot be changed because of the limitation of the bridge width in the case of the box-type PSC beam), but the I-type PSC beam, the box-type PSC beam, etc. In all the PSC beams in which the abdomen is formed, it can be seen that the decrease in the width of the abdomen and the width of the upper and lower flanges increase the cross-sectional stiffness of the PSC beam.

In particular, in the type I PSC beam, when the width of the abdomen is increased by 20% and the case when the width of the abdomen is reduced by 25% based on the width of 200 mm of the abdomen of the rectangular cross section, the change of stress according to the construction steps is as described above.

In other words, when the abdominal width was reduced by 25% in the PSC beam manufacturing step, the introduction stress improvement effect was 10% .In the case of the PSC beam which reduced the abdominal width by 25%, it was 39% in the post-construction use phase. It can be seen that the corresponding stress improvement effect occurs.

As a result, the present invention adopts a method of obtaining an effect such as increasing the cross-sectional stiffness of the PSC beam by reducing the width of the abdomen to the minimum in the PSC beam.

First, as the I-girder, the abdomen of the PSC beam is limited to reduce the width b of the abdomen.

For example, the width (b) of the abdomen in which the left and right sheaths, the left and right vertical rebar diameters, the left and right horizontal rebar diameters, and the sheath (tube) diameter for passing the tension member or the stranded line should be at least secured as shown in FIG. Is the minimum width (b) of.

Assuming that the minimum width (b) of the abdomen, the present invention

A PSC beam having an end section L1, a general section L2, and an abdominal cross-section minimization section L3, divided according to the tension member arrangement form over an entire extension length L,

First, the general section (L2), which is the abdominal section in which the tension member is disposed, ensures the minimum width (b) as above.

Second, the abdominal cross-sectional minimization section L3, which is an abdominal section in which the tension member is not disposed, is formed such that the width of the abdomen is smaller than the minimum width b1 <b as shown in FIG. 2B.

Thus, the width of the abdomen of the present invention is formed in the cross-sectional shape as shown in Figure 2a and 2c with the boundary between the abdominal section where the tension member 110 is disposed and the tension member is not disposed over the entire length of the PSC beam. .

That is, the minimum width (b) of the abdomen is the minimum width of the abdomen that can be installed in the concrete cover, the diameter of the reinforcing bar, the tension material, the end section (L1) and the general section (L2) is a conventional cross section, general section (L2) And the abdominal cross-section minimizing section (L3) of the width of the abdomen is different from each other to be formed as a side cross section of the present invention.

At this time, in order for the upward stress due to the stress introduced into the PSC beam lower flange of the present invention to be transferred from the lower flange to the upper flange, the abdomen needs a certain thickness or more, and the buckling due to the compressive stress occurs due to the reduced abdomen width. Can be. Therefore

Third, the present invention is to form the abdominal buckling reinforcement 130 in the abdomen to solve this. This abdominal buckling reinforcement is to be installed to prevent the buckling of the abdomen unlike the cross beam finishing portion for the horizontal beam installation in the conventional PSC beam, unlike the conventional crossbeams as shown in Figures 2a and 2c to be formed of concrete only on both sides of the abdomen do. Of course, the cross beam finishing portion for the conventional cross beam installation is installed to be connected to the upper, lower flange to distribute the load transmitted from the cross beam.

Fourth, the present invention has a structure in which the tension member cannot be disposed in the abdomen except for both end portions of the PSC beam because the width of the abdomen is reduced. Therefore, the tension member is formed in the extension length of the entire PSC beam is located only within the lower flange.

Therefore, in the abdominal section where the tension member is not disposed because the tension member is concentrated on the lower flange, the compressive stress due to the tension stress is increased in the lower flange, and in order to further enhance the concrete compressive resistance performance according to the effect. As shown in FIG. 2B, the closed transverse restraint bar 120 surrounding the tension member 110 inside the lower flange is disposed.

In general, in order to arrange the tension member in the PSC beam, the lower flange of the PSC beam has been applied to the upper part of the reinforcing bar which is reinforced to the part where the lower flange and the abdomen are connected. This is because the longer the span of the bridge, the longer the steel wire is placed in the abdomen, the longer the section is, the ease of installation of the tension material and the upper portion of the reinforcing bar was formed in an open shape so that the concrete to be poured is not blocked at the connection between the abdomen and the lower flange.

However, the present invention reduces the width of the abdomen in order to improve the efficiency of the cross-section, the longer the section is not placed tension tension, even if the reinforcement transversely constricted reinforcing bar is not the same problem does not occur as above constrain the lower flange By improving the concrete compressive resistance against the concentrated stress, the same effect as the cross-sectional stiffness is further increased.

After all, the present invention

In the PSC beam, the width of the abdomen is minimized based on the marginal width of the abdomen except for the section in which the tension is arranged in the abdomen according to the arrangement of the tension material.

In the abdominal section in which the tension member is not disposed, the lower flange has a technical feature to reinforce the closed transverse restraint bars.

[PSC beam 100 optimizing abdominal cross section of the present invention]

3A and 3B show front and partial cross-sectional views of the PSC beam 100 optimizing the abdominal cross section of the present invention.

First, FIGS. 3A and 3B are both symmetrical with respect to the center portion of the PSC beam 100, so that the cross-sectional shape of the left side and the arrangement of the tension member 110 are illustrated.

That is, it is divided into the end section L1, the general section L2, and the abdominal cross section minimization section L3 of the PSC beam.

First, the end section L1 is a section in which fixing devices are installed on both end faces of the PSC beam, and the tension member 110 passes through the abdomen throughout the cross section. It can be seen that formed.

It can be seen that the general section L2 is a section which is continuous with the end section L1 and is formed in an I-type cross section as a section through which tension material passes through the abdomen without a fixing device installed.

It can be seen that the general section (L2) is formed in a more extended length in comparison with FIG. 3b in the case of Figure 3a, which is only a classification according to the arrangement of the tension member (110).

Accordingly, it can be seen that the end section L1 and the general section L2 have a tapered shape in which the width of the abdomen is changed because the width of the abdomen is different.

Abdominal cross-section minimizing section (L3) is a section in which the tension member 110 is disposed only on the lower flange of the PSC beam while having a width smaller than the minimum width (b) of the abdomen as described above, this abdominal cross-section minimizing section (L3) is In the case of Figure 3b it can be seen that much longer than in comparison with Figure 3a and thus the shape according to Figure 3b can be seen that corresponds to the method of maximizing the effect of the present invention.

In the abdominal cross-section minimization section (L3), the tension member 110 is disposed only on the lower flange, so that the transverse restrained reinforcement 120 is closed to surround the tension member.

In general, the closed transverse constrained reinforcing bar 120 is generally manufactured in the form of an open upper part as shown in FIG. 3C, because it is not easy to arrange the tension member when it is combined. However, in the abdominal cross-sectional minimization section of the present invention, since the tension member is not disposed in the abdomen, the closed transverse restraint steel 120 is used.

This can maximize the compressive stress introduced into the lower flange by the confinement effect of the lower flange.

As a result, in the abdominal cross-section minimizing section (L3) and the general section (L2), it can be seen that the width of the abdomen is changed again so that the cross-sectional section is also formed.

As a result, the PSC beam 100 according to the present invention extends the abdominal cross section minimizing section L3 through the longitudinal direction to form the width of the abdomen as a cross section in a section excluding both ends of the PSC beam, and minimizes the abdominal cross section. It can be seen that the tension member 110 is disposed only in the lower flange (L3), and the transverse constrained reinforcing bar 120 is disposed in the lower flange.

Furthermore, the PSC beam of the present invention is formed in the abdomen buckling reinforcement 130 to the abdomen, which is formed only on both sides of the abdomen, unlike the conventional crossbeam. Of course, the horizontal beam finishing portion for the conventional horizontal beam installation is installed to be connected to the upper, lower flanges in order to distribute the load transmitted from the cross beam.

[Method for Producing PSC Beam 100 with Optimized Abdominal Cross Section]

If the manufacturing method is described based on the post-tension method,

First, the formwork for manufacturing the PSC beam is installed on the workbench, and in particular, the width of the abdomen is an end section (L1) at both ends of the PSC beam so as to secure a space for fixing the fixing device for the tension member. At (L2), the minimum width (b) of the abdomen is secured, and at the abdominal cross-section minimum section (L3), the abdomen width (b1) smaller than the minimum width is produced. Furthermore, to form a form to be formed in the abdomen buckling reinforcement 130 to the abdomen, and also to have a form of form for forming a cross beam finish for conventional crossbeam installation.

Next, the internal reinforcing bar assembly is disposed inside the formwork, and in particular, the abdominal cross-section minimizing section (L3) has a confined transverse constrained reinforcement 120 in the longitudinal direction so that a plurality of intervals are arranged at a predetermined interval (CONFINE). EFFECT).

Next, the tension member 110 is disposed inside the formwork. The tension member 110 is generally disposed in a parabolic shape or in a straight shape, but in particular, the tension member 110 is disposed only in the lower flange inside the closed transverse restraint rod 120 in the abdominal cross-sectional minimization section. Will be done.

Next, after pouring concrete into the formwork and curing, the formwork is demolded, and the tension material is fixed to the fixing device after the tension, so that compression prestress is introduced.

Furthermore, the pretension method will explain

First, the formwork for manufacturing PSC beam is installed on the fabrication table for pretension, and the formwork of the form of the abdomen has a width of the abdomen (L1) at both ends of the PSC beam so as to secure a space for fixing the tension fixing device. In general section (L2) to ensure the minimum width (b) of the abdomen, in the abdominal cross-section minimizing section is to be manufactured to have a smaller abdomen width (b1) than the minimum width, the pretension tension material Is placed on the workbench first to strain it. These tension members are placed in a straight line.

Also to produce a formwork so that the abdominal buckling reinforcement 130 is formed in the abdomen, and also to have a form of formwork for forming a crossbeam finish for conventional crossbeam installation.

Next, the inner reinforcing bar assembly is disposed inside the formwork, and in particular, the abdominal cross-section minimizing section has a confined transverse constrained reinforcement 120 in a longitudinal direction so that a plurality of intervals are arranged to have a confinement effect. Is the same.

Next, in the abdominal cross-sectional minimization section (L3), the tension member 110 is disposed only on the lower flange inside the closed transverse restraint bar 120.

Next, after the concrete is poured into the formwork and cured, the formwork is demoulded and the tension material is cut to allow compression prestress to be introduced.

[Bridge Construction Method Using PSC Beam with Optimized Abdominal Section]

As described above, the construction method will produce the PSC beam of the present invention at a manufacturing site as described above. The PSC beam is formed in the shape of the cross section of the abdomen in the general section (L2) and the abdominal cross section minimizing section (L3) as shown in Figure 3b, and further, the abdominal buckling reinforcement 130 is formed in the abdomen It can be seen that the present invention will be described with reference to FIG. 4.

Next, the fabricated PSC beam 100 optimized for the abdominal cross-section of the present invention is mounted by using a bridge support, that is, a bridge substructure, that is, between alternations and alternations or between alternations and piers, piers and piers.

Next, the cross beams are connected to both ends of the cross beam finishing portions formed in the PSC beam 100 so as to constrain the girders in the transverse direction.

Next, the slab 200 is installed on the PSC beam 100 to complete the bridge construction using the PSC beam in which the abdominal cross section of the present invention is optimized.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

100: PSC beam with optimized abdominal cross section
110: tension material
120: closed transverse constrained bar
130: abdominal buckling reinforcement
200: slab
L1: end section
L2: General Section
L3: Abdominal section minimization section

Claims (7)

A PSC beam having an end section L1, a general section L2, and an abdominal cross section minimization section L3, divided according to the tension member arrangement form over the entire extension length (L = L1 + L2 + L3),
The end section L1 is a section in which fixing devices are installed on both end surfaces of the PSC beam 100, and the tension member 110 passes through the abdomen over the entire cross section and has a rectangular spherical shape in order to secure a fixing device installation space. Formed into
The general section (L2) is a section that is continuous with the end section (L1) is formed in the cross section through the tension material in the abdomen having a minimum width (b),
The abdominal cross-sectional minimization section L3 is a section continuous with the general section L2 and has an abdominal width b1, b> b1 smaller than the minimum width b of the abdomen and is a tension member only in the lower flange of the PSC beam 100. Is formed into a cross section in which 110 is disposed,
The minimum width (b) of the abdomen is a concrete covering, the diameter of the reinforcing bar, the minimum abdomen width that can be installed in the tension material, the end section (L1) and the normal section (L2) and the normal section (L2) and the abdominal cross-section minimum section ( The connecting part of L3) is formed so that the width of the abdomen is different from each other to form a cross section,
In the abdominal cross-sectional minimization section, a tension member is disposed only in the lower flange of the PSC beam, and a plurality of lateral restrained reinforcement rods 120 are disposed in the abdominal cross-section minimization section L3 in the longitudinal direction of the PSC beam to surround the disposed tension member 110. PSC beam with optimized abdominal cross section, characterized in that the reinforcement spaced apart. The method of claim 1,
The abdomen buckling reinforcement member 130 is further formed on the PSC beam abdomen of the abdominal cross-section minimization section L3, wherein the abdominal buckling reinforcement member 130 is to prevent buckling of the abdomen separately from the cross beam finishing part for installing the cross beam. A PSC beam with optimized abdominal cross section, characterized in that formed so as to be formed only on both sides of the abdomen of the PSC beam. A method for manufacturing a PSC beam having an end section (L1), a general section (L2), and an abdominal cross-section minimization section (L3), which are divided according to the tension member arrangement form over the entire extension length (L = L1 + L2 + L3). The width of the end portion (L1) of both ends of the PSC beam to secure the space for fixing the tension fixing device, the general section (L2) to ensure the minimum width (b) of the abdomen, minimize the abdominal cross section In the section L3, the abdomen width b1 may be smaller than the minimum width b, and the abdominal buckling reinforcement 130 may be formed in the abdomen sectional minimization section L3 at the abdomen of the PSC beam. In addition to the formwork to form a crossbeam finish for the crossbeam installation on the workbench,
The abdominal cross-section minimizing section (L3) inside the formwork so that a plurality of closed transverse restrained reinforcing bars 120 are arranged at regular intervals in the longitudinal direction,
If the cured after pouring concrete into the formwork, including the step of demolding the formwork,
In the abdominal cross-sectional minimization section in the formwork PSC beam manufacturing method of the abdominal cross section, characterized in that the tension member 110 is arranged only in the lower flange inside the closed transverse constrained reinforcement (120). The method of claim 3, wherein
The minimum width (b) of the abdomen is a concrete covering, the diameter of the reinforcing bar, the minimum abdomen width that can be installed in the tension material, the end section (L1) and the normal section (L2) and the normal section (L2) and the abdominal cross-section minimum section ( The connection part of L3) has an optimized width of the abdominal cross section, characterized in that the width of the abdomen is different from each other to form a cross-section. A PSC beam having an end section L1, a general section L2, and an abdominal cross-section minimization section L3, divided according to the tension member arrangement form over an entire extension length (L = L1 + L2 + L3), wherein the end section ( L1) is a section in which fixing devices are installed at both end faces of the PSC beam, and the tension member is formed in a rectangular spherical cross section to secure a fixing device installation space through the abdomen throughout the cross section, and the general section (L2). Is a section continuous to the end section and formed of an I-shaped section through which a tension material passes through the abdomen having a minimum width, and the abdominal cross section minimizing section L3 is a section continuous to the general section and is smaller than the minimum width b of the abdomen. It has a small abdomen width (b1) and is formed of an I-shaped cross section in which the tension member is disposed only in the lower flange, the minimum width (b) of the abdomen is a concrete covering, the diameter of the reinforcing bar, the minimum abdominal width that can be installed of the tension member, the end phrase PSC beam 100 optimized for the abdominal cross-section so that the connection between the liver L1 and the general section L2 and the general section L2 and the abdominal cross-section minimization section L3 is formed with a different cross-section of the abdomen. To produce
Mounting the PSC beam 100 optimized the abdominal cross section to the bridge substructure,
And forming a slab on the upper part of the PSC beam having optimized abdominal cross section. 6. The method of claim 5,
In the abdominal cross-section minimization section (L3), the tension member is disposed only on the lower flange of the PSC beam, and a plurality of closed constrained reinforcement bars 120 are enclosed to surround the disposed tension member 110 in the longitudinal direction of the abdominal cross-section. Bridge construction method using the PSC beam with optimized abdominal cross section, characterized in that the reinforcement spaced apart. The method according to claim 5 or 6,
The abdomen buckling reinforcement member 130 is further formed on the PSC beam abdomen of the abdominal cross-section minimization section L3, wherein the abdominal buckling reinforcement member 130 is to prevent buckling of the abdomen separately from the cross beam finishing part for installing the cross beam. The bridge construction method using the PSC beam with optimized abdominal cross section, characterized in that formed so as to be formed only on both sides of the abdomen of the PSC beam.

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