KR20020059960A - Precasted Concrete using a Fiber Reinforced Concrete and method for construction - Google Patents

Abstract

PURPOSE: A precast floor panel is provided to enhance tensile strength of the floor panel and creep dry-shrinkage property and after completing a structure, to improve management and repairing thereof by applying fiber reinforced concrete. CONSTITUTION: The floor panel comprises floor panels(30,40) having annular parts(43) of backing reinforced bars; and fiber reinforced concrete inside the panels(30,40). The panels(30,40) have multiple rectangular grooves(34) containing bolt groove at lateral side and stud(36) to be coupled to a girder(32) for supporting the panels(30,40) at lower portion. The bolt groove is provided with a leveling bolt to control horizontal error at connection of the floor panels along length of the bridge. The rectangular groove(34) is introduced by mortar(38) after coupling to the stud(36) to be used as the panels(30,40).

Description

Precasted concrete using a Fiber Reinforced Concrete and method for construction}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bottom plate temporary construction method for constructing a bridge, and more particularly, to a precast floor plate using a fiber reinforced concrete (FRC) and a temporary construction method thereof.

In general, precast prefabricated bridges consist of columns, girders, and precast panels (or decks), which can be used to replace aging bridges, where full-depth precast or precast prestressed concrete bridges can be used to replace aging bridges. These precast elements are structures supported on precast prestressed or reinforced concrete girders as well as steel beams and plate girders.

In the case of installing the precast panel, the method of laying the next panel by placing the crane on the already installed panel for the convenience of the temporary construction method is the most advantageous construction method, but in this case, the weight of the crane is considered separately in the design of the mold. Should be done.

In addition, when the prestress panel is introduced, since the work space of the tension jack is necessary, the installation of the expansion and contraction device causes the work space for tension to be widened after the tensioning.

Figure 1a is a view showing a structure for coupling the PC precast plate used as the bottom plate of the bridge, Figure 1b is a view showing a structure for joining the RC precast plate used as the bottom plate of the bridge, Figure 1c is a bridge The figure which shows the structure which couple | bonds the precast synthetic bottom plate used as the bottom plate of the.

The bridge's bottom plate structure illustrates what kind of precast deck plate is used and what the seams are treated with.

As can be seen in FIG. 1A, the PC precast plate is provided with PC steel 12 therein, and each PC precast plate 10, 20 is treated with a grout 14.

As can be seen in Figure 1b, the RC precast plate is provided with a main reinforcing bar 16 therein, and each RC precast plate 10, 20 is a reinforcing bar 18 coupled to the main reinforcing bar 16 in the joint After the installation is processed to the filling material (22).

As can be seen in Figure 1c, the precast composite bottom plate is provided with a cast reinforcing bar 16 therein, and each of the precast composite bottom plate 10, 20 is a low steel plate 24 and the clasp at the bottom of the joint After installation of 26, the joint is treated with filler 22.

The PC precast plate, RC precast plate, and precast composite floor plate are given the same numerals (10) and (20) to aid in understanding of the drawings.

As mentioned above, the most problematic problem in pre-stressed steel bridges is the loss of prestress and cracking of joints. The bottom plate of all bridges is to solve the cracking problem of joints. Although it is a predecessor problem, when connecting the bottom plate and the other bottom plate in the conventional structure did not solve the above problems.

The present invention to solve the above problems, the present invention improves the tensile strength characteristics and creep dry shrinkage characteristics to improve the connection of the joints and at the same time to improve the strength of the fiber mixed in the precast deck The purpose of the present invention is to provide a precast deck using a fiber-mixed concrete and its temporary construction method, which have advantages in terms of future maintenance and repair after the bridge is completed.

The present invention, in order to achieve the above object, the present invention, the bottom plate of the bridge incorporating fibers in order to strengthen the strength of the bottom plate and to strengthen the dry shrinkage characteristics, the annular portion of the reinforcement reinforcement to the joint portion protrudes outward The parts are interconnected to each other, and the bottom plate and the bottom plate are formed with a rubber sealing tape as a substitute for formwork, and then the filling material is poured to fix the joints. The bottom plate has a square groove penetrating from the top surface to the bottom surface. A plurality of bolt grooves are formed, and studs are installed in the square grooves to couple with the girder, and the nut part of the bolt grooves installed adjacent to the square grooves is coupled with a leveling bolt to adjust the bottom plate while adjusting the horizontal error of the bottom plate. Temporarily fix, remove the leveling bolt after finishing filling of the filler material to the joint of the bottom plate and fill the bolt groove with Fix the sealing tape to both sides of the upper flange of the bottom plate of the girder at the front end connection of the bottom plate, fix the stud to the upper flange, and then finish filling the filling material, and fix the stud to the square groove. After mortar is poured, the girders are pre-fabricated using fiber mixed concrete, in which the bottom plates are connected to each other so as to tension the rails to the tension coupler installed in the lower part to offset the tensile stress of the parental region. Cast floor plate and its construction method are provided.

Figure 1a is a view showing a structure for joining the PC precast plate used as the bottom plate of the bridge, Figure 1b is a view showing a structure for joining the RC precast plate used as the bottom plate of the bridge, Figure 1c is a bottom of the bridge The figure which shows the structure which joins the precast synthetic bottom board used as a board.

Figure 2a is a schematic view showing a state in which the bottom plate using the fiber mixed concrete is installed on the bridge bottom plate of the present invention, Figure 2b is a view showing a state cut part AA of Figure 2a, Figure 2c is a bottom plate of Figure 2b Figure 2 is a view showing the structure of the connection portion, Figure 2d is a view showing a state of connecting the shear connection of the bottom plate of the present invention.

Figure 3a is a plan view of the bottom plate of the present invention, Figure 3b is a cross-sectional view showing a bolt groove and a leveling belt of the bottom plate of the present invention, Figure 3c is a view showing a plate girder of the present invention, Figure 3d is a hypothesis of the bridge of the present invention Drawing for explaining the construction method.

<Brief description of symbols for the main parts of the drawings>

30,40: Sole 32: Girder

34: square groove 35: bolt groove

36: stud 37: leveling bolt

38: mortar 39: nut part

42 spacer 43 annular portion

44: tension coupler 45: upper flange

46: rail 47: sealing tape

49: Filler 50: Metal Fiber

52: cast iron 54: power reinforcing bar

56: filling material 58: plate girders

EMBODIMENT OF THE INVENTION Hereinafter, with reference to an accompanying drawing, the structure and working state of this invention are demonstrated.

FIG. 2A is a view schematically showing a state in which a bottom plate using fiber mixed concrete is installed in a bridge bottom plate of the present invention, and FIG. 2B is a view illustrating a state in which the AA portion of FIG. 2A is cut, and FIG. 2C is a view of FIG. 2B. It is a figure which shows the structure of the connection part of a bottom plate, and FIG. 2D is a figure which shows the state which connects the front end connection part of the bottom plate of this invention.

As can be seen in Figure 2a, the bottom plate 30, 40 of the bridge is used in conjunction with the girder 32, the bottom plate 30, 40 is of the girder 32 through the square groove 34 The upper surface is fixed via the stud 36, the mortar 38 is poured into the square groove 34, the bottom plate 30, 40 and the girder 32 are fixed to each other.

The bottom plate 30, 40 is formed with a groove on the side in the longitudinal direction, the spacer 32 is formed on the upper surface of the girder 32. The girder 32 is provided with a tension coupler 44 at the bottom to couple the rail 46 to give tension to the post.

As it can be seen in Figure 2b and Figure 2c, each of the adjacent bottom plate 30, 40 is provided with a sealing tape 47 on the side of the joint, the bottom plate 30, 40, the main reinforcing bar ( 52) and the reinforcement reinforcement 54, and the bottom plate 30, 40, the joint portion of the expandable fiber mixed concrete in the state in which the annular portion 43 connected to the reinforcement reinforcement 54 and each other facing each other 49 is poured, the metal plate 50 is protruded to the outside in the bottom plate 30, 40 is solidified with the metal fiber 50 mixed therein.

Various kinds of the fiber may be used, and as the fiber material, metal fiber, glass fiber, and carbon fiber are used to enhance tensile strength and dry shrinkage property.

The joint surface except for the surface to which the sealing tape 47 of the bottom plates 30 and 40 is attached is surface treated so that the aggregate surface and the fiber are exposed to improve the adhesion performance by using a water jet after manufacturing the bottom plate. And, the joint spacing is to have a spacing of approximately 30 ~ 50cm.

In the bottom plate (30) 40, a metal fiber (steel fiber) 50 protrudes to the outside of the joint, if the metal plate 50 is placed in the bottom plate 30, 40 about 1.2 ~ 2.5% The fracture energy of fiber-mixed concrete is increased by 20 to 70 times that of ordinary concrete.

The metal fiber 50 has an ultimate strength of about 13.5 kN when a metal fiber having a length of 60 mm and a diameter of 0.8 mm is inserted into a beam of 600 × 150 × 150 mm ³ of 450 mm span about 60 kg / m. Ultimate strength is about twice that of concrete with reinforcing bars (wire mesh). As the content of the metal fiber increases, the ultimate strength greatly increases, the amount of energy dissipation is small even after the ultimate strength is reached, and the energy dissipation rate is also reduced.

Increasing the percentage of the metal fiber 50 not only greatly increases the load-carrying capacity, but also when the crack occurs because the metal fiber catches cracking even when concrete reaches the ultimate strength. It increases the load to be applied up to, and also prevents the progress of the cracks and reduces the gap interval because the metal fiber catches the progress of the cracks even after the cracks in the concrete.

Looking at the creep dry shrinkage characteristics of the concrete containing the metal fiber 50 is as follows.

In general, the creep coefficient of plane concrete generally increases continuously after one year. In the case of concrete with metal fiber, it is fixed at a fixed value after 300 days, especially by adding about 2.0% of metal fiber. Dependent deflection is reduced by 20% and 0.3 ~ 0.75% is reduced by 10%.

The metal fiber connecting the crack and the crack of the concrete suppresses the increase in strain in the tensile region because the creep does not occur even if the stress acts on the concrete, thereby reducing the curvature and deflection in the beam.

Under load conditions above 0.58 P _u , time-dependent deflection of 0.61 to 0.69 of instantaneous deflection occurs, but under the load conditions of 0.98 to 0.77% of time-dependent deflection, metal fiber has high load. This is more effective in controlling time-dependent deflection in the system.

The time-depedent deflection, which occurs for one year under load conditions of 0.58 P _u (approximately 80% until 135 days after loading) is about 0.75 of instantaneous deflection, which is 0.96 and 1.26 after 6 and 9 months in conventional reinforced concrete. The amount is much reduced compared to the occurrence.

The dry shrinkage strain is usually constant 250 days after wet curing, in the case of plane concrete _{sh, u} value is 354.02 (× 10 ^-6) If the member into the metal fibers in the degree or 2.0% 297.52 (× 10 ^-6) comes about.

As can be seen in Figure 2d, the shear connection of the bottom plate 30, 40 is sealed between the bottom-shaped upper flange 45 and the bottom plate 30, 40 formed on top of the girder 32. A tape 51 is coupled, and a stud 36 is fixed to the upper flange 45, and a filling material of non-shrink mortar is attached to the shear connection part sealed by the bottom plates 30 and 40 and the upper flange 45 ( 56) is poured out and finished.

Figure 3a is a plan view of the bottom plate of the present invention, Figure 3b is a cross-sectional view showing a bolt groove and a leveling belt of the bottom plate of the present invention, Figure 3c is a view showing a plate girder of the present invention, Figure 3d is a view of the present invention It is a figure for demonstrating the construction method of a bridge.

As can be seen in Figures 3a and 3b, the bottom plate 30, 40 is formed with a bolt groove 35 on the side formed with a square groove 34, the nut is formed with a screw thread in the bolt groove 35 The part 39 is inherent.

A leveling bolt 37 is coupled to the nut part 39 of the bolt groove 35, and the leveling bolt 37 is capable of adjusting a step between the bottom plates 30 and 40 to a minute portion, and the leveling. The reason for using the bolt 37 can be temporarily fixed by adjusting the height, it is possible to remove the leveling bolt and fill the mortar when the casting is completed.

As can be seen in Figure 3c, the hypothesis method of the present invention schematically illustrates a state using a plate-shaped girders.

In FIG. 3D, the reason for introducing the compressive force in the temporary construction method of the present invention is schematically explained by using the moment diagram of the two-span continuous bridge, and the bottom plate is treated as cracking force due to tension, and prestress is introduced to solve the problem. The compressive force is introduced to the bottom plate and the joint in this part to cancel the tensile stress.

As described above, the bottom plate 30, 40 includes the metal fiber 50, and the tensile strength, dry shrinkage characteristics and creep characteristics are improved due to the connection between the bottom plate using a rail, the existing bridge The strength is much higher than that of the bottom plate.

Effects of the configuration and operation of the present invention described above will be described.

The bottom plate of the bridge containing the metal fiber of the present invention has better applicability of the new bridge than the precast bottom plate having no reinforcing bar portion joints, and it is necessary to set a site casting section separately to absorb construction errors. Almost no, it is also easy to be applied to curved bridges or social bridges, and has the advantage that can be combined with the prestressing method by external steel wire or point forced settlement.

The bottom plate structure of the bridge containing the metal fiber has been shown to exhibit excellent performance in crack control and thereby significantly extend the punching shear fatigue life, which is the main mode of failure of the bottom plate, especially in concrete with shrinkage and creep characteristics. Compared with this, the loss of the introduced axial prestress can be reduced to a considerable level, so that the economic efficiency can be achieved.

In addition, by incorporating fibers into the bottom plate of the bridge, the amount of contracted reinforcement bars (reinforced reinforcement bars) that are reinforced in the axial direction can be used to a minimum, so the details of the reinforcement can be simplified. It is effectively applied to steel box girder bridges, and has an advantageous aspect in terms of maintenance and repair of future bridges.

Claims (3)

In the bottom plate of the bridge, the bottom plate 30, 40 is formed so that the annular portion 43 of the reinforcing bar 41 is protruded outwardly at each joint portion, and the bottom plate 30, 40 In order to enhance the strength and to strengthen the drying shrinkage characteristics, the fiber is mixed inside, the bottom plate 30, 40 is formed with a plurality of square grooves 34 penetrating from the upper surface to the lower surface and the square groove A bolt groove 35 is formed at a side thereof, and the square groove 34 has a stud 36 installed therein, which is coupled with a girder 32 supporting the bottom plate from the bottom thereof, and the bolt groove 35. Leveling bolts (37) are installed therein to control the horizontal error when the bottom plate is connected in the longitudinal direction of the bridge, while the mortar (38) is poured after the studs (36) are coupled to the square groove (34) bridge Precast floor using fiber-mixed concrete, characterized in that used as the bottom plate 30, 40 . The method of claim 1, wherein the fibers to be mixed in the bottom plate is a precast deck construction method using a fiber-mixed concrete, characterized in that the metal fiber, glass fiber and carbon fiber is used. In order to reinforce the strength of the bottom plate and to strengthen the dry shrinkage characteristics, the bottom plate 30, 40 of the bridge incorporating the fiber has a portion where the annular portion 43 of the reinforcing bar 41 protrudes outward from the joint portion. The bottom plate 30 and the bottom plate 40 are interconnected to each other, and a rubber sealing tape 47 is formed as a substitute for formwork, and then a filling material 49 is poured to fix the joints, and the bottom plate 30 In the 40, a plurality of square grooves 34 and bolt grooves 35 penetrating from the upper surface to the lower surface are formed, and the studs 36 are installed in the square groove 34 to be coupled to the girder 32. The leveling bolt 37 is coupled to the nut part 39 of the bolt groove 35 installed adjacent to the square groove 34 to temporarily adjust the bottom plate 30 and 40 while adjusting the horizontal error of the bottom plate. After fixing the filling material to the joints of the bottom plate 30, 40, the leveling bolt 37 is removed and the bolt groove ( The filling material is fixed to the filling material 35, and the sealing tape 47 is fixed to both sides of the upper flange 45 of the convex shape of the girder 32 at the front end connection portions of the bottom plates 30 and 40. The stud 48 is fixed to the 45 and then the filling material 49 is poured into the finish, and the mortar 38 is poured into the square groove 34 after the stud 36 is fixed. The fiber mixing concrete, characterized in that by connecting each of the bottom plate 30, 40 to tension the rail 46 to the tension coupler 44 installed on the bottom to offset the tensile stress of the parental region Precast decking construction method using