KR101898558B1 - Bridge constructing method using girder having center-concentrated tendon - Google Patents

Abstract

The objective of the present invention is to secure cost efficiency by reducing tendon costs while increasing efficiency of a cross section of a girder center portion and increase free stress efficiency by increasing the neutral axis of the girder. The girder having a centralized tendon of the present invention comprises: a girder extending in the transverse direction and having a left side of the girder, a center of the girder, and a right side of the girder; and a tendon passing through the lower portion of the girder in the transverse direction and including a first tendon and a second tendon. The first tendon is disposed on the left side of the girder and in the center of the girder. Moreover, the second tendon is disposed in the center of the girder and on the right side of the girder.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a bridge construction method using a girder having a centralized type tendon,

The present invention relates to a method of manufacturing a bridge using a girder having a centralized type tendon. More particularly, to a girder having a centralized type tendon in which tendons are intensively disposed at the center of a girder, and a method of making a bridge using the girder.

In the bridge field, the girder bridge and the Rahmen bridge are mainly used.

In the girder bridges, the girder which is the superstructure of the bridge is manufactured, and the girder is placed on the bridge substructure (wall, bridge). These girder bridges are advantageous in that they can be constructed easily and economically.

It can be seen as a modification of the ramen disturbed girder bridges. The connection between the bridge overhead structure and the bridge underground structure is poured into concrete and integrated. Since it does not require bridge support and expansion joint, it is convenient to manage the glass and has excellent durability. .

However, girders used in girder bridges or girder bridges are used to reinforce the center of the girders in order to prevent the girders from concentrating on the central part of the girders during the use process. There was a lot of problems.

In order to give pre-stressing to the girders used in girder bridge or ramen bridge, a tendon is arranged on the lower side of the girder, which is generally extended from one end of the girder to the other end .

There is a prior art registration number 1073390 (method of laying the tent, which is registered on October 7, 2011), but this prior art also has a tendon extending from one end of the girder to the other, As shown in Fig.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a girder structure capable of improving cost efficiency by improving the cross- It is an object of the present invention to provide a girder having a centralized type tendon.

Another object of the present invention is to provide a girder which minimizes tensile stress by reducing the compressive force at the time of tensile pulling at the end by embedding (fixing) one end of the tendon in the middle of the girder.

In order to achieve the above object, the present invention provides a girder comprising: a girder which extends in the lateral direction and includes a left side of the girder, a center of the girder and a right side of the girder; And a tendon passing through the lower portion of the girder horizontally and including a first tendon and a second tendon,

The first tendon is disposed on the left side of the girder and the center of the girder, and the second tendon is disposed on the center of the girder and the right side of the girder.

A third tent which is symmetrical with the first tent on a plan view; Wherein the first tendon and the third tendon have a slope inclined in a downward direction of the girder, thereafter a straight portion, and a straight portion in a direction of the center of the girder The inclined portion 26c inclined in the direction of the center of the last girder through the inclined portion inclined in the downward direction of the girder, and then the straight portion, the second inclined portion and the fourth inclined portion, . ≪ / RTI >

The right end of the first tendon and the left end of the third tendon are fixedly embedded in the inside of the girder, and the left and right ends of the first tendon and the second tendon Wherein the girders are provided with four hollow portions along the longitudinal direction and the hollow portions include a lower inclined portion in which the height of the girder is reduced at both side ends thereof, and an upper reinforcing plate made of a metal and an upper reinforcing plate It is preferable that a shear connecting member is provided.

Meanwhile, a method of manufacturing a bridge using a girder having a centralized type tendon according to the present invention includes the steps of: placing the first to fourth tents in a predetermined position and casting concrete to form a girder; Tensioning the first tent of the girder and fixing it on the left side of the girder; Tensioning the second tension of the girder and fixing it to the left side of the girder; Tensioning the third tenter of the girder and fixing it on the right side of the girder; And tensioning the fourth tensen of the girder so as to fix it on the right side of the girder.

A girder having a centralized type tendon and a method of manufacturing a bridge using the same according to the present invention can improve the sectional efficiency of the girder central portion and reduce the cost of the tender to thereby ensure economical efficiency and improve the neutral axis of the girder, And the like.

In addition, by embedding (fixing) the one end of the tendon in the middle of the girder, it is possible to minimize the tensile stress by reducing the compressive force when the tensile is tensioned at the end.

1 is a side view of a girder having a centralized tendon according to the invention;
2 is a plan view of a girder with a centralized tendon according to the invention;
3 is a cross-sectional view taken along lines (a) and (h) in Figs. 1 and 2;
FIG. 4 is an enlarged view of a left portion of the girder 10 in FIG. 1; FIG.
5 is a side view and a cross-sectional view of a girder having a centralized tendon according to another embodiment of the present invention;
FIG. 6 is a side view and a cross-sectional view showing another embodiment in which the intermediate fixing unit is exposed to the outside in FIG. 5; FIG.
Figures 7 to 11B show conditions and results of sensitivity analysis according to the position of the tendon of the centralized tendon according to the present invention.

While the present invention has been described in connection with certain embodiments, it is obvious that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In the drawings, the same reference numerals are used for the same reference numerals, and in particular, the numerals of the tens and the digits of the digits, the digits of the tens, the digits of the digits and the alphabets are the same, Members referred to by reference numerals can be identified as members corresponding to these standards.

In the drawings, the components are expressed by exaggeratingly larger (or thicker) or smaller (or thinner) in size or thickness in consideration of the convenience of understanding, etc. However, It should not be.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the term " comprising " or " consisting of ", or the like, refers to the presence of a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a girder having a centralized type tendon and a method of manufacturing a bridge using the same according to the present invention will be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side view of a girder with a centralized tendon according to the present invention. Referring to FIG. 1, the girder 10 is a substantially rectangular reinforced concrete extending in the left-right direction, and is provided with through-tethers 20 (22, 26) penetrating the lower portion in the left-right direction. The girder 10 has a first boundary 11a and a second boundary 11b formed at approximately 1/3 and 2/3 points in the longitudinal direction of the girder 12, the girder center 14 and the girder right side 16).

The tent (20) includes a first tent (22) and a second tent (26). The first tent 22 is disposed from the left end of the girder 10 to the second boundary 11b, that is, in the region of the left side 12 of the girder and the region of the girder 14. The second tent 26 is disposed in the region from the right end of the girder 10 to the first boundary 11a, i.e., the region of the right side 16 of the girder and the region of the girder 14.

As a result, the first tent 22 and the second tent 26 overlap each other in the region of the center 14 of the girder, and the first tent 22 and the second tent 26 are disposed on the left side 12 and the right side 16, Only the tendon 26 is disposed. 2, which is a plan view, as will be described below, the first tendon 22 and the second tendon 26 are shown as overlapping in the region of the girder center 14 of FIG. 1, And the second tent (26).

After the girder 10 is installed with a bridge such as a girder bridge or a ramen bridge, a load is concentrated near the center of the girder 10. In the conventional girder, the same number of tendons are arranged in all the regions of the girder 10. However, in the girder having the centralized type tendon according to the present invention, since the tendon 20 is concentrated around the center of the girder 10, the load concentrated at the center of the girder 10 can be further reinforced, It is possible to provide an effect of reducing the installation cost of the tent 20.

The first and second tendons 22, 26 extend in the horizontal direction and are provided in the girder 10, but the left and right ends are bent upward. The left end of the first tendon 22 located at both ends of the girder 10 and the right end of the second tendon 26 are also bent upward and the first tendon 22 located at the first boundary 11a And the left end of the second tent 26 located at the second boundary 11b is also provided on the upper side. The right end 22e of the first tenter 22 and the left end 26e of the second tenter 26 become the embedding fixed end to be embedded in the girder 10. [ In the present invention, in the present invention, one end of each tendon is a buried fixed end to be embedded in the girder 10, while the other end is only one end of the girder, and the other end is exposed to the left and right ends of the girder. And is exposed to the outside of the girder 10, so that only one side of each tensile is pulled to give a prestress. Here, only the first and second tendons 22 and 26 will be described with reference to Fig. 1, but the third and fourth tendons 24 and 28 shown in Fig. 2 have the same structure.

At the center of the girder 10, a hollow portion 13 is formed along the longitudinal direction. The hollow portion 13 is a space formed at a central portion to reduce the weight of the girder 10, and a light member such as styrofoam may be filled in the hollow portion. The hollow portion 13 is not formed at the center of the girder 10 and at the first boundary 11a and the second boundary 11b. Therefore, four hollow portions 13 are formed in the girder 10, and the four hollow portions 13 are provided with a lower inclined portion 13a at both side ends of the girder 10, the vertical height of which decreases. The lower inclined portions 13a correspond to bending of both ends of the tendon 20 upward, and provide a space in which the tendons 20 are installed.

2 is a plan view of a girder having a centralized tendon according to the present invention. 2, the planar shape of the girder 10 is rectangular as shown in Fig. 1, and the tent 20 is divided into a second tent 26 and a fourth tent 24 in addition to the first tent 12 and the third tent 24, (28) is additionally shown. The second tendon 26 is vertically symmetrical with the first tent 12 and the fourth tent 28 is vertically symmetrical with the second tent 26 in plan view. The side shapes of the second tent 26 and the fourth tent 28 are the same as those of the first tent 12 and the second tent 26 of Fig.

2 and 3, the tethers 20, 22, 24, 26 and 28 are disposed at positions offset from each other at the both ends of the girder 10, (I.e., end portions). However, the first and third tendons 22, 24 are arranged again at the centered position in the vicinity of the girder center 14, in order to prevent overlap with the second and fourth tendons 26, 28.

Therefore, when viewed from the left side of the plane shape of the first tent, the inclined portion 22a inclined downward, then the straight portion 22b, and the inclined portion inclined toward the center of the girder 10 22c, and including the last rectilinear section 22d. Although the reference numerals are not shown for the third tendon 24, they are symmetrical with respect to the first tendon 22.

When the shape of the third tent 26 is viewed from the right side, an inclined portion 26a inclined downward of the girder 10, and then a straight portion 26b, (26c). Likewise, the fourth tent (38) is not shown, but has the same shape as that of the third tent (26).

Due to the arrangement of the tents 20, four tents 22, 24, 26, and 28 are arranged at regular intervals in the girder center 14, and in the vicinity of the left side 12 and the right side 16 of the girder, The two tensenes 22 and 24 or 26 and 28 are arranged at regular intervals to improve the efficiency of the center section of the girder 10 to provide the optimum prestress to the girder 10. [

3 is a cross-sectional view taken along lines (a) and (h) in Figs. 1 and 2.

3 (a), it is confirmed that the first tent 22 and the third tent 24 are located at the lower center of the left side 12 of the girder. In the conventional tent arrangement method, four tents are disposed at the end portion and two pieces are arranged on the upper side of the girder and two pieces are arranged on the lower side. However, in the girder having the centralized type tendon according to the present invention, Only the tents 22 and 24 are disposed.

Referring to FIG. 3 (b), the hollow portion 13 is shown and two tandems 22 and 24 are arranged on both sides of the lower portion of the left side 12 of the girder. 3 (b), the hollow portion 13 is smaller than the hollow portion 13 of (d) because the lower inclined portion 13a is formed. As a result, it is possible to sufficiently provide a space in which the tendons 22 and 24 are bent upwardly from the end portion of the girder 10.

Referring to FIG. 3 (c), four tenses 22, 24, 26 and 28 are visible, and a second tender 26 and a fourth tender 28 are located at the center, (See Fig. 1). The hollow section 13 is not formed on this partial cross section, in order to fix the embedding fixed end.

Referring to FIGS. 3 (d) and 3 (e), all four tendons 22, 24, 26 and 28 are visible, which corresponds to the girder center 14.

3 (f) corresponds to the second boundary 11b, and FIG. 3 (f) shows a similar arrangement to that of FIG. 3 (c), in which the tendon is changed vertically. The second and fourth tendons 26 and 28 are disposed under the girder 10 and the first and second tendons 22 and 24 are positioned at the center. The first tent 22 and the third tent 24 become embedding fixed ends 22e that are buried and fixed at this position.

FIG. 3 (g) is the same as FIG. 3 (b), but only the tendon is changed to the second and fourth tendons 26 and 28. FIG. 3 (h) is the same as FIG. 3 (a), but only the tendon is changed to the second and fourth tendons 26 and 28.

Referring to FIG. 4, which is an enlarged view of the left part of the girder 10 in FIG. 1, an upper reinforcing plate 30 made of a metal is provided on the girder center 14 of the girder 10. The upper reinforcing plate 30 serves to mount the reinforcing bar 32 on the upper portion of the girder 10 as will be described later, but serves to raise the neutral axis of the girder 10. In other words, the center of the girder 10 is positioned above the center. In the process of reinforcing the girder 10 by the tension of the girder 10 installed at the lower part of the girder 10, It is possible to disperse the prestress acting on the girder 10 during the tensioning process.

On the surface of the upper reinforcing plate (30), a plurality of shear connectors (32) penetrating up and down are provided. The lower portion of the shear connector 32 is embedded in the surface of the girder 10 and the upper portion of the shear connector 32 is projected to the upper portion of the girder 10. The upper part of the shear connection member 32 protruding to the upper part of the girder reinforces the composite of the concrete and the girder 10 when the concrete is laid after the girder is installed.

The method for manufacturing the above-described girder 10 will be described. First, the first to third tendons 22 to 28 are positioned at predetermined positions, and concrete is laid to manufacture a girder. Thereafter, the first tensioner 22 is tensioned and fixed on the left side of the girder, and the second tensioner 24 is tensioned on the left side of the girder. Then, the third tension 26 is tensioned and fixed on the right side of the girder. Finally, the fourth tension 28 is tensioned and fixed on the right side of the girder.

3, the order of tensioning the toe tendons 22, 24, 26 and 28 is to stretch the tendons in the order of left / right inside the girder 10 and left / right order outside the girder 10 Results. In this way, tensile strength is applied to the girder 10 in succession from the inner side to the outer side and alternately between the left and right sides, thereby minimizing the tensile stress acting on the girder 10 and giving the pre-stress.

5 is a side view and a cross-sectional view of a girder having a centralized type tendon according to another embodiment of the present invention, wherein only the left side 12 of the girder to the girder center 14 are shown and the right side of the girder is omitted. 5, the girder is an I-shaped girder 40 rather than a rectangular one. The I-shaped girder 40 has an I-shaped cross section as shown in Fig. 5 and does not have a hollow portion 13 (see Fig. 2).

The technical idea of a girder having a centralized type tendon according to the present invention is also applicable to the I-type girder 40, and the arrangement of the tents 22 and 26 is also the same. However, the embedding fixed end for fixing and fixing the second tent 26 and the fourth tent 28 to the first boundary 11a can not be installed inside the I-shaped girder 40, It is necessary to further form a structure 42 in which a buried fixed end is to be installed.

6, which is a side view and a cross-sectional view showing another embodiment in which the intermediate fusing part is exposed to the outside in FIG. 5, one end of the first to fourth tents 22, 24, 26, 40) are exposed to the outside of the central side. The other end of each of the four tensors 22, 24, 26 and 28 is fixed to the end of the I-shaped girder 40, but one end of the other is not buried in the I- As shown in FIG. As a result, while the tendons are concentrated on the center side of the girder 40, both end portions of the tents 22, 24, 26 and 28 are exposed, so that the prestressing operation is performed by tensioning the tendon.

In the past, techniques for concentrating tendons at the center of the girder have been known. However, one of the sides of the tendon is embedded in the girder. One side of the tendon is fixedly embedded in the girder, and only one end of the tendon exposed to the outside is pulled It was common to apply prestress. However, in this case, stress was concentrated on one side of the tendon, and there was a danger that the tendon would be broken and the end of the tendon embedded in the girder could be dropped. By exposing both ends of the tendon to the outside of the girder while concentrating the tendon at the central portion of the girder, it is possible to prevent the risk of falling off the tendon end in the girder while dispersing the stress to both sides of the tendon.

The Applicant has also studied the length lay ratio of the centralized girders. Sensitivity analysis was performed under the same conditions as FIG. 7 to determine the most efficient intermediate fixation position. Fig. 7 (a) shows the test conditions based on the span of 30 m of span (bridge and bridge, or bridge and bridge), and (b) of 40 m of span. The load applied here was the fixed load on the girder and the bottom plate, and was taken as the uniformly distributed lane load considering the impact factor. The impact of the strand loss and other loads was not taken into account. Fig. 8 is a summary of the materials used in this experiment.

As shown in FIG. 9, the span length (L) was divided into three to six sections. The arrangement of the strand in the longitudinal section is assumed to be linear except for some sections such as the end for the strand stop.

The cross section stresses according to the intermediate fixation positions are shown in a graph and the results are summarized in the table as shown in FIG. 10A when 4-stranded 15.2 mm 17 strands are arranged in a 30-m-long bridge and 15.2 mm 17 strands are arranged in two strands.

As a result of considering the stresses of the girder for each variables of 30m span girder, it was found that the middle settlement of the strand near L / 5 (0.20L) was the most efficient when the girder was arranged linearly. In order to determine the intermediate settlement position of the stranded wire more effectively, further investigation was conducted on 0.22L ~ 0.18L with reference to this result. The result is shown in FIG. 10B. As a result of studying the stresses of the girder for each parameter of 30m span girder, it was found that it is the most efficient to settle the strand at 0.21L when the strand is linearly arranged.

FIGS. 11A and 11B show the same results as above for a bridge having a length of 40 m. The result shows that it is effective to perform an intermediate settlement of the strand at the 0.21L position.

Therefore, it is most effective to middle settle the strand at 0.21L and 0.79L with respect to the length (L) of the landscape.

Meanwhile, in the method of making a bridge using a girder having a centralized type tendon according to the present invention, a reinforcing concrete can be additionally installed after a tent (strand) is fixed. The composition of the reinforced concrete is as follows.

The wax or paraffin may be contained in an amount of 3 to 4% by weight based on 100% by weight of the entire concrete composition. The wax or paraffin has a melting point of 40 to 60 DEG C and serves to lower the production temperature of the cement, to melt the cement with chemical resistance, and to provide the effect of not being volatilized and not deteriorating in quality after curing. When the wax or paraffin is added in an amount of less than 3% by weight, the effect of addition is scarcely added. If the wax or paraffin is added in an amount of more than 4% by weight, the brittleness of the cement increases to easily break.

The styrene thermoplastic elastomer may also be contained in an amount of 1 to 2% by weight. It has a hard segment of polystyrene block in the short term of the sock and a soft segment structure of polybutadiene in the middle. It has a low viscosity when it is dissolved in a mixed solvent and has high elasticity and low temperature durability. The synthetic zeolite powder dispersed in the particulate state exhibits a function of preventing cracking of the waterproof coating film caused by elapsing time and lifting of the waterproof coating caused by lack of low temperature durability during the winter season. The waterproof coating has the advantage of showing additional functions such as soundproofing and sound absorption

And 2.5 to 3.5% by weight of an amine-based curing agent. If the content of the amine-based curing agent is less than 2.5% by weight, the strength and durability may be lowered and the physical properties may be deteriorated. If the content of the amine-based curing agent is more than 3.5% by weight, the viscosity is increased and the workability is deteriorated.

And 1.5 to 3% by weight of an amorphous polyolefin. This amorphous polyolefin (APO) is a strong adhesive material which is obtained by polymerizing olefins such as ethylene and propylene, and lowers the thermal conductivity of cement during the summer season.

Further, it may further contain 0.5 to 0.7% by weight of iron slag. This iron slag is a slag generated when refining steel and scrap iron in an electric furnace to produce steel, preventing plastic deformation of the cement, preventing port holes in pavement roads, and preventing road slippage . When the content of the iron slag is less than 0.5% by weight, the effect thereof is not high. When the content of the iron slag is more than 0.7% by weight, the increase in the effect is insignificant.
(The reinforced concrete composition may further include residual cement and water. The mixing ratio of water and cement can be selected according to the viscosity desired. The implementation of the cement and water composition is well known to those skilled in the art. You can do that.)

It will be apparent to those skilled in the art that various modifications and variations can be made in the invention without departing from the spirit and scope of the invention as defined by the appended claims. And is within the scope of the claims.

10: girder 11a: first boundary
11b: second boundary 12: girder left side
13: hollow portion 13a: lower inclined portion
14: girder center 16: girder right
20: Tennessee 22: First Tennessee
24: 3rd Tendon 26: 2nd Tendon
28: fourth tent 30: upper reinforcement plate
32: shear connection member 40: I-type girder

Claims (2)

The girder left side 12, the girder center 14 and the right side of the girder 12 extend in the left-right direction with respect to the first boundary 11a and the second boundary 11b formed at 0.21L and 0.79L in the direction of the length L, (10) comprising a plurality of projections (16); And
A first tent 22 which penetrates the lower portion of the girder 10 in the left and right direction and which is disposed on the left side 12 and the center 14 of the girder and the right side 16 of the girder, A third tendon 24 that is symmetrical with the first tendon 22 on a top view and a fourth tendon 24 that is symmetrical with the second tendon 26 on a top view, 28; < / RTI >
/ RTI >
The first tent 22 and the third tent 24 are formed by inclining portions 22a inclined downward of the girder 20 and then by a linear portion 22b, Via the inclined portion 22c, including the last straight portion 22d,
The second tender 26 and the fourth tender 28 are inclined by an inclined portion 26a inclined downwardly of the girder 10 and then by a straight portion 26b to be inclined And an inclined portion 26c,
The left and right end portions of the first tenter (22) and the second tenter (26) are bent upward,
The right end 22e of the first tenter 22 and the left end 26e of the third tenter 24 are fixedly embedded in the inside of the girder 10,
Four hollow portions 13 are provided along the longitudinal direction at the center of the girder 10 and the hollow portions 13 include a lower inclined portion 13a whose vertical height is reduced at both side ends of the girder 10 In addition,
The first to fourth tendons 22, 24, 26 and 28 are arranged at positions offset from each other at the both ends of the girder 10 and the first and third tendons 22 and 24, And the second and fourth tendons 26 and 28 are disposed at positions offset from the upper and lower ends of the girder 10 in the vicinity of the center of the girder 14, Respectively,
An upper reinforcing plate 30 made of a metal and a shear connecting member 32 passing through the upper reinforcing plate 30 are provided at the upper center of the girder 10,
The first tender 22 and the third tender 24 have planar shapes that are inclined from the left side to the lower side of the girder 10 and then are straight portions 22b, Through the inclined portion 22c inclined in the direction of the first straight line 22d,
The shape of the second tent 26 and the fourth tent 28 is such that the inclined portion 26a inclined downward from the right side of the girder 10 and then the final girder 10 via the straight portion 26b, And an inclined portion (26c) inclined in the center direction,
One end of each of the first to tenth (22) to the fourth (28) is exposed to the outside of the center side of the girder, and the other end is fixed to the end of the girder (10)
The right end 22e of the first tendon 22 and the left end 26e of the second tendon 26 are buried in the girder 10 so that one end of each tendon is connected to the girder 10 And a center central tendon which is exposed to the outside of the girder 10 and pulls only one side of each of the tensions to give a prestress. According to the method for manufacturing a bridge using a girder having a centralized type tendon,
Placing the first to fourth tendons 22, 24, 26, and 28 in a predetermined position, and then pouring concrete into the girder 10;
Tensioning the first tent (22) of the girder and fixing it to the left side (12) of the girder;
Tensioning the second tenter (26) of the girder and fixing it to the left side (12) of the girder;
Tensioning the third tent (24) of the girder and fixing it to the right side (16) of the girder; And
A step of pulling the fourth tensen (28) of the girder and fixing it to the right side (16) of the girder
Lt; / RTI >
After the step of manufacturing the girder 10,
Wherein the composition contains 3 to 4 wt% of wax or paraffin, 1 to 2 wt% of styrene thermoplastic elastomer, 2.5 to 3.5 wt% of amine curing agent, 1.5 to 3 wt% of amorphous polyolefin and 0.5 to 0.7 wt% of iron slag Further comprising the step of casting the reinforced concrete. delete

Images