WO2013157732A1

WO2013157732A1 - The composite girder having web members with various patterns

Info

Publication number: WO2013157732A1
Application number: PCT/KR2013/001464
Authority: WO
Inventors: 원대연
Original assignee: Won Dae-Yon
Priority date: 2012-04-15
Filing date: 2013-02-25
Publication date: 2013-10-24
Also published as: JP6010215B2; JP2015514172A; CN104246074B; KR20120054578A; CN104246074A; KR101406938B1

Abstract

The present invention relates to the development of a composite girder, comprising steel web members, a concrete lower cord member and a concrete upper floor plate. Conventional composite truss girders having a concrete lower cord member have problems to be solved such as the generation of localized large sectional force in a connection system section due to the use of a firmly coupled connection system, and problems caused by mounting a partition wall in a middle support, or the like. The present invention uses various patterns for web members instead of a conventional triangular truss structure so as to smoothly transfer force between members and to develop a composite girder bridge for converting the structure type of a main girder from a truss structure to a beam structure according to a main construction step. To this end, the composite girder of the present invention comprises: a framed structure made from a steel material of which the structural behavior is similar to a truss; a concrete lower cord member for completely surrounding the lower steel material of the framed structure; a concrete web member for filling a part of a web space of the framed structure; and a concrete floor plate coupled to the upper cord member of the framed structure. The composite girder of the present invention can appropriately utilize the advantages of the truss structure and the beam structure and the advantages of the steel material and the concrete according to construction conditions and construction steps.

Description

Compound girders with various patterns

In the present invention, a skeleton structure composed only of steel is first manufactured in a factory and transported to a construction site, and then a composite girder structure that resists external loads by being integrated with a concrete member and a shear connector at a work site or a pier, After manufacturing the tubular or rolled steel by bending processing using high-frequency heating, a unit member of a predetermined shape is manufactured, and then, the unit members are joined through a connecting plate to form a member having a variety of shapes. Combine the longitudinal beam members to the lower part to make the skeleton structure of the steel, and then join the longitudinal beam members attached to the lower part of the skeleton structure with the concrete member of the predetermined shape, and fill the hollow hollow member with concrete Make a housing consisting of a composite cross section, the structural behavior of which is then attached to the upper part of the skeleton structure The longitudinal beam members and to join the upper concrete floor plates relates to the development of a composite girder as main features.

The present application is filed while claiming priority based on the Republic of Korea Patent Application No. 10-2012-0038850, the contents described in the application specification of the Republic of Korea Patent Application No. 10-2012-0038850 is included herein.

Conventional dwellers have a tucked structure with the abdominal wall closed or a triangular perforated space. The main difference between the two types of structure is that the housing girder, which has a cladding structure, resists the external force in the vertical direction through the shear force of the abdominal member, and the housing girder, which has a truss structure, resists the axial force of the sand.

In the case where the housing sheath has a filling structure, it is preferable to change the thickness or height of the abdominal member according to the change of the shear force in terms of material use. The countermeasure for varying the thickness of the abdominal member according to the magnitude of the shear force may be used properly when the abdominal member is made of steel sheet. There is a problem that is not determined.

In addition, when the abdomen is made of concrete, the thickness of the abdominal member is generally determined based on the maximum shear force. Consequently, the abdominal member always has a margin of resistance against the shear force, and the self-weight increases more than necessary. Brings about.

In order to prevent the girder weight from increasing due to the excessive use of the abdominal member, it is effective to reduce the height of the housing, but the problem is that the height of the housing is not determined by the shear force, but the magnitude and deflection of the bending moment in the housing. It is mainly determined by such constraints. The most efficient way to increase the housing girder's resistance to bending moments and deflections is to increase the housing girder's height, but increasing the housing girder's height increases the surplus of the resistance to shear forces, thereby increasing unnecessary self-weight and This results in increased bending moments.

In addition, in the continuous beam structure, the shear force increases and the magnitude of the bending moment also increases, so the method of responding to the change in shear force by changing the height of the housing can be partially applied, but in the simple beam structure, the shear force and the bending moment Since changes tend to be inconsistent or opposite, the reduction in shear force does not reduce the height of the dwelling.

On the other hand, when the abdomen is a truss structure, the vertical load that causes the shear force in the filling structure is transmitted to the axial force of the yarn, so that the cross-sectional specifications of each yarn can be changed according to the size of the shear force. It can fundamentally solve the problem. The most effective way to reduce the weight of the house is to use the truss structure type with excellent structural efficiency while using steel with good material efficiency. The type of truss structure is different in appearance and name depending on the shape of the abdominal member. The best type of structural characteristics and material efficiency is the warren truss structure in which alternating materials are subjected to compressive and tensile forces.

The warren truss structure transfers the vertical loads to the point through the shortest path, and is used for composite truss girders using concrete in truss chords because of its excellent resistance to external horizontal loads such as prestressing forces. have. In other words, the axial force acting on the adjacent sand is converted from compressive force to tensile force at the lower gap where it meets the concrete lower chord. In this process, the horizontal force is transmitted to the concrete lower chord. At this time, when the center axis of adjacent sand material and the center axis of the concrete lower chord do not coincide at one point, a large shear force and an eccentric moment are acting in the gap section. In order to ensure that the concrete lower chord can withstand these forces safely, connect the two materials. The use of PS steel for reinforcement of the gap point using embedded steel and reinforcement of appropriate shape and introduction of pre-compression force in concrete lower chord.

As mentioned earlier, the beam-type housing girders are made in most cases so that the abdominal portion, which resists shear forces, is made to have a greater resistance than the actually acting vertical force, resulting in an increase in the amount of unneeded girders. . The longer the span length, the greater the proportion of the cross-sectional force due to the girder weight. Therefore, in order to reduce the construction cost and construction cost more efficiently, it is necessary to reduce the girder weight by optimizing the shape of the member.

On the other hand, the use of the truss structure in the abdomen is a very effective countermeasure for reducing the weight, but due to the following specificity of the truss structure type, special care is required in design and construction. In the triangular truss structure with the combination of straight members, the direction of sudden force change is made between the connected members in all the intervals. The closer to the point, the greater the axial force acting on the sand, and the greater the magnitude of the local shear force at the critical point. However, the yarn axial force increases at the point of the outermost span of the simple support structure or the continuous support structure, but the magnitude of the axial force due to the bending moment occurring in the phase current decreases rapidly as the point approaches the point. In other words, there is a problem in the thickness difference between the serious members that the steel sheet thickness of the phase current is thin while the steel sheet thickness of the sand material in this section, and to prevent the smooth transfer of force and local shear deformation of the phase current. To this end, the use of additional stiffening plates is inevitable.

In the truss structure, forces having different directions of action intersect each other at the intersecting points of the upper and lower chords that resist the axial force and the bending moments, and these forces intersect each other along the central axis of each member. Careful attention must be paid to the design to ensure that the points at one point correspond. In the conventional steel truss structure, a very large gusset plate is additionally attached to the gap point section so that the action forces of the truss constituent members connected to each other meet at one point within each other.

However, in the case of composite truss girder bridges using steel pipes in the composite material and having a low chord of concrete, various problems of using exposed large gusset plates, maintenance problems due to corrosion of concrete and steel contact surfaces, and relative Due to problems such as aesthetic damage due to low girder height, the steel defect point structure that is embedded in the concrete current is mainly used. In this case, the axial force acting on the adjacent sand is transmitted directly or indirectly through the concrete current. . In this process, the vertical component of the axial force acting on the sand and the local bending moment due to the stiffening process are generated at the critical point, and special care must be taken to ensure that the forces do not cause harmful cracking in the concrete undercarriage. .

On the other hand, the longer the span, the greater the difference in the absolute magnitude of the axial force acting on the yarn according to the position, and accordingly, the specifications of the yarn and the critical point to be used should be varied. However, the use of too many types of sand and gaps to avoid design and fabrication simplification often results in the use of more steel than is necessary for calculations.

In order to solve the problem of unnecessarily increasing steel usage due to the remarkable cross-sectional force difference between the members of the truss, there is a method of applying the double warren truss structure that overlaps the warren truss with the truss' counter-thickness interval. The number of critical points that require maintenance is rather doubled, and it is not used well except in very special cases due to problems such as intersecting the intersecting sections, dismantling the spots in the middle piers, and poor visibility. Do not.

In addition, one of the issues that arise when applying a composite truss girder with a concrete lower chord in a continuous structure is a phenomenon in which a very large bending moment occurs in the concrete lower chord due to the local flexural strain restriction at the mid-point. This is caused by the fact that the concrete lower chords are connected to the continuous beam members with flexural stiffness in the gap section, unlike the ideal truss behavior in which all the member elements constituting the truss are pinned together at each other.

In order to solve the above problems, unlike conventional steel truss bridges, in the composite truss girder bridges, a concrete bulkhead having a very high rigidity is additionally installed at each intermediate point over one or three or more striking points of the truss to generate local concrete under current. Although it is intended to resist the bending moment, the cost increase due to the bulkhead installation, the capacity increase of the use base due to the increase of its own weight, and the increase of the specification of the lower support structure are accompanied separately.

As described above, the conventional composite truss girder having a concrete lower chord exhibits the structural behavior of the truss in the overall force flow, so that the original purpose of self-weight reduction can be achieved, Additional challenges such as inconsistency in the tendency of cross-sectional force generation, limitations in the use of various materials and gap specifications, generation of large local cross-sectional forces in the gap section due to the use of steel defect points, and problems due to the installation of intermediate point bulkheads Have.

In the present invention, in order to solve the problems of the above-described composite truss girder, instead of the conventional triangular truss structure, various types of patterns that can transmit a smooth force between the members are used in the abdominal member, the housing according to the main construction stage To develop a composite girder bridge that converts the structural form of a truss structure into a beam structure.

In order to achieve the above object, the composite girder of the present invention is a frame structure made of steel having a structural behavior similar to truss, concrete completely surrounding the lower steel of the skeleton structure, concrete filling a part of the abdominal space of the skeleton structure The abdominal member and the concrete base plate are combined with the phase current of the skeleton structure.

At this time, as a skeleton structure of steel, a member having a circular or semi-circular shape is used for the abdominal member instead of the conventional truss structure in which a pair of straight yarns alternates with a constant inclination angle where the pair of straight yarns meets the upper or lower chords. This creates a load path in which the vertical force applied to the abdominal member is transmitted directly to the adjacent abdominal member without passing through the upper and lower chords. By allowing the axial force directions of the to be parallel or perpendicular to each other, the force is transmitted between the members by direct shear in which the force is transmitted in the shortest distance.

In the abdominal member of steel frame structure, the vertical force can be transmitted through the direct coupling between the abdominal members through the use of a heart-shaped member. By placing them side by side, the transfer of force between the abdominal member and the lower chord can be such that the intersection angle between the members is about 70 degrees, so that the gap size is greatly reduced compared to the conventional truss structure. In addition, since the length of the portion in which the linear axial member is formed is significantly shortened, the resistance to buckling under compressive force is greatly improved, and the inclination angle of the yarn can be steeped while maintaining the same gap point. The specification is reduced. Here it is. By overlapping the abdominal member and the phase chord over almost all of the gap points, a portion of the vertical force can be transmitted through the shear resistance of the phase current and the abdominal part.

Further, when the rhombic member is continuously arranged in the abdominal member of the skeleton structure, the same structural behavior as that of dispersing the axial force acting on the abdominal member, as in the conventional double warren truss, can be secured. In addition, the vertical force generated in the abdominal member is transmitted through the direct shear between the abdominal members without passing through the upper and lower chords, and the horizontal force generated by the direction change of the axial force acting on the abdominal member is also in the form of the direct current and the lower chord. Can deliver at present.

Apart from changing the shape of the abdominal member described above to reduce the magnitude of the force acting on the gap point, another main object of the present invention is to convert the structural form of the housing girder from the similar truss structure to the beam structure according to the construction stage. The method is to produce a light weight composite girder that can support the vertical force acting on the housing girder not only by the axial resistance of the abdominal member but also by the shear resistance of the abdominal member, the upper chord, the lower chord and the joint reinforcement plate. In other words, the truss-like structural behavior is to be the dominant structure in the step of forming a dweller using the skeleton structure of steel, which is the basic skeleton of the dweller, and the dwelling step is combined with the upper floor concrete and the dwelling is in common. Let the beam represent the structural behavior of the beam.

Comparing the composite girder according to the present invention by the weight of each constituent member, the skeletal structure of the steel is 15%, the concrete lower chord 30% and the concrete top plate 55% of the total weight, respectively, to be used in the bridge structure In this case, the additional fixed load such as curb and pavement and the moving load of the vehicle are about 30% of the composite girder. That is, the vertical force up to the stage where the concrete undercarriage is formed is about 35% of the total size, and the vertical force applied to the housing after the common stage is about 65%, and the vertical force through the shear resistance of the housing If the structure can share the size of the abdominal member can be reduced, and as a result it is possible to greatly reduce the size of the gap installed in the place where the abdominal member and the upper or lower chord meet.

In order to achieve the above object, the composite girder according to the present invention fills the remaining space, except the space surrounded by only the abdominal member of the openings installed in the abdomen with a thin reinforced concrete structure of about 150mm thickness to exhibit the same structural behavior as the beam .

1 is a plan view of a unit member for manufacturing the abdominal member according to the present invention.

Figure 2 is a cross-sectional view of the member used for manufacturing the unit member according to the present invention.

Figure 3 is a schematic view of the apparatus for bending the unit member according to the present invention.

Figure 4 is a shape of the steel skeleton structure according to the present invention.

5 is a flow chart of the inter-member force of the steel frame structure according to the present invention.

Figure 6 is an illustration of a steel skeleton structure that can be produced in combination between unit members according to the present invention.

Figure 7 is a composite girder construction sequence according to a first embodiment of the present invention.

8 is a composite girder construction sequence according to a second embodiment of the present invention.

Figure 9 is a composite girder construction sequence according to a third embodiment of the present invention.

1: Circular unit member for manufacturing abdominal member

2: heart-shaped unit member for manufacturing the abdominal member

3: inequality unit member for manufacturing abdominal member

4: Semi-circular unit member for manufacturing abdominal member

5: Fixed clamp for bending the unit member

6: high frequency heating device 7: fixed roller

8: Upper current of steel skeleton structure 9: Lower current of steel skeleton structure

10 unit connection plate 11 point reinforcement plate

12: unit member lower connecting plate 13: shear connector

14: concrete lower current 15: concrete top plate

16: abdominal concrete 17: high-strength PS steel

Hereinafter, with reference to the accompanying drawings showing an embodiment in order to explain the contents of the present invention in detail.

Figure 1 shows the shape of the unit member used for manufacturing the abdominal member according to the present invention. As shown in Figure 1, the composite member of the composite girder according to the present invention has the shape of a circle (1), a heart (2), an inequality (3), and a semicircle (4) bent to a predetermined radius (R) It is manufactured to have various patterns at regular intervals using unit members.

Figure 2 shows the cross-sectional shape used in the unit member according to the present invention, the cross-section of the circular steel pipe, square tube or rolled steel (H-shaped steel, c-shaped steel) that can be minimized the change in material properties according to bending process Is done.

Figure 3 shows an overview of the device for manufacturing a unit member according to the present invention. As shown in FIG. 3, the fixing clamp 5 is attached to maintain the constant radius at the beginning of the curve, and then the linear member passes the high frequency heating device 6 in front of the fixing roller 7. It is bent to have a predetermined radius (R). In other words, by performing bending processing through high-temperature high-frequency heating, it is possible to minimize the damage to the material properties of the steel material, it is possible to reduce the radius of the curve more than two times compared to cold processing at room temperature.

Figure 4 shows the shape of the steel skeleton structure that can be implemented using a unit member according to the present invention. A similar truss structure that can be implemented using the unit member according to the present invention can be largely divided into four basic shapes.

First, the circular unit member 1 is connected to each other through welding of the connecting plate 10 to form the abdominal member, and then the upper chord 8 and the lower chord 9 are welded to the upper and lower portions of the abdominal member, respectively. A steel skeleton structure having a circular opening in the abdomen is produced by attaching the abdominal reinforcing plate 11 to both ends of the skeleton to form a skeleton structure (Fig. 4 (a)).

The steel frame structure having a heart-shaped opening in the abdomen forms the abdominal member by connecting the curved portions of the heart-shaped unit member 2 through the welding of the connecting plate 10 to form an abdominal member. The upper chord 8 is welded along the horizontal straight section, and the lower part of the abdominal member is welded to each other by welding the reinforcement plate 12 and the lower chord 9 welded together to close the heart-shaped unit member 2. It is produced (Fig. 4 (b)).

The steel skeleton structure having a rhombic pattern opening in the abdomen is arranged with the curved portions of the unit member 3 of the inequality shape facing each other and then connected to each other by welding of the connecting plate 10 to form a abdominal member. It is produced by welding the upper chord 8 and the lower chord 9 to the upper and lower portions of the abdominal member, respectively (Fig. 4 (c)).

Steel frame structure having semicircular pattern openings on the abdomen is formed by connecting the lower ends of the semicircular unit members 4 through welding to form abdominal members, and then, respectively, the upper chords 8 and the upper and lower portions of the abdominal members, respectively. It is produced by welding the lower chord 9 (Fig. 4 (d)).

Figure 5 shows a flow chart of the inter-member force of the steel skeleton structure according to the present invention. As shown in Fig. 5 (a), when the circular unit member is used for the abdominal member, the vertical force due to external load acts as a shear force at the position where the abdominal member meets the upper chord and the lower chord, and the abdominal members meet each other. In the center, the direction of the force is switched by the axial force in the vertical direction, and the behavior of the unit member to rotate toward the smaller vertical force due to the difference in the vertical axial force (V1, V2) applied to the connection point between the front and rear of the unit member. In order to restrain this rotational behavior, compressive forces C1 and C2 are generated in the upper chord and tensile forces T1 and T2 in the lower chord, respectively. That is, in the conventional truss structure, all the vertical force is transmitted only by the straight yarn axial force, but in the skeleton structure having a circular abdominal structure according to the present invention, the structure resists the vertical force through a circular structure having excellent structural resistance of high order irregularity. Has characteristics.

As shown in Fig. 5 (b), when the heart-shaped unit member is used for the abdominal member, a triangular truss structure is formed on the upper and lower chords with respect to the connection point between the unit members, and as a result, the unit member The vertical force (V1, V2) applied to the connection point is divided into two truss structures located at the upper and lower sides, and the vertical force is generated by the vertical force component transmitted to the upper truss. Tensile forces (T1, T2) are generated in the lower chord by the force component, respectively. In the conventional truss structure, the axial force acting on the sand is always kept constant in size and direction over the entire length of the member. Although the phenomenon of concentrating only on the gap point occurred, in the skeleton structure having a heart-shaped abdomen structure according to the present invention, the magnitude and direction of the force acting on one abdominal member can be changed differently according to the position of the gap point that meets the present. Reduces the absolute magnitude of the vertical force acting on it. In addition, the connection point between the abdominal members where the vertical force is concentrated is placed between the upper and lower chords so that a part of the vertical force can be shared through the shear resistance of the upper and lower chords.

As shown in Fig. 5 (c), when a lozenge-shaped abdominal member is constructed by using an inequality unit member, two triangular truss structures having the same specifications as the upper and lower chords are formed on the basis of the connection point between the abdominal members. As a result, the vertical force (V1, V2) applied to the connection point of the unit member is equally distributed between the two truss structures located at the top and bottom, and the compressive force (C1, C2) at the present time due to the vertical force component transmitted to the upper truss. ), And the tension force (T1, T2) is generated in the lower chord due to the vertical force component shearing the lower truss. That is, the skeleton structure having the abdominal structure of the lozenge shape according to the present invention exhibits the same structural behavior as the conventional double warren truss structure.

On the other hand, as shown in Fig. 5 (d), in the case of having a semicircular abdominal member, the vertical load acting on the upper chord acts as a concentrated load at the position where the upper chord and the abdominal member meet, and this concentrated load acts as an arch of the abdominal member. The horizontal force and the vertical reaction force are converted at the position where the abdominal member and the lower chord meet, and the horizontal force causes tension (T1, T2) at the lower chord, and the vertical reaction force is applied to the adjacent abdominal cavity through the direct shear between the abdominal members. Delivered. On the other hand, the vertical load acting on the lower chord is transmitted to the point through the bending resistance of the lower chord, which acts as a continuous beam structure with the end of the abdominal member of the semicircle as the point. Is passed toward the vertex of. The vertical force is converted into horizontal force and shear force at the apex of the semicircle, respectively, and the horizontal force causes the compressive force (C1, C2) of the phase current, and the shear force (V1, V2) is applied to the end of the opposite abdomen through the arch action of the abdominal member Delivered.

Figure 6 shows the shape of the steel skeleton structure having a patterned abdominal member made by combining two or more unit members of the same or different shape according to the present invention.

First, as shown in Fig. 6 (a), the circular unit member 1 is circular by using an unequal unit member 3 having an internal angle at right angles to the abdominal member connected to each other through the connecting plate 10. By further connecting the unit member 1 through the upper chord 8 and the lower chord 9, the shear force and the moment generated in the circular abdominal member 1 are greatly reduced, and the upper chord and the lower chord The effect of dispersing the vertical load currently applied can be obtained.

Another method to reduce the shear force and the moment generated in the circular unit member 1 is a pair of inequality arc-shaped unit members 3 having a right angled inner shell is welded inside the circular unit member 1 so that the abdominal member It is made to be shaped like a wheel of an automobile (Fig. 6 (b)).

In addition, as shown in Fig. 6 (c), the pair of heart-shaped unit members 2 face each other with respect to the horizontal line, and then the connecting plate 10 is welded to have a butterfly-shaped pattern having a butterfly pattern. Steel skeleton can be made.

On the other hand, the steel frame structure having the semicircular abdominal member has the advantage of securing the widest area of opening compared to the abdominal member having other patterns when the abdominal member height is the same. The disadvantage is that the size of the moment is significantly larger than other types. In order to compensate for these disadvantages, as shown in FIG. 6 (d), the upper chord 8 and the lower chord are added by adding two inequality-shaped unit members 3 having different sizes inside and outside the semicircular member 4. When a new load transfer path connected to (9) is generated, the shear force and bending moment magnitude generated in the semicircular member can be significantly reduced, and the bending moments generated in the upper chord and the lower chord are greatly reduced.

Figure 7 shows a composite girder construction sequence according to a first embodiment of the present invention. Composite girder according to the present invention can be manufactured using only the steel skeleton structure consisting of only the abdominal member when the construction method including the self-weight before the girder is supported by a separate support facility is applied. First, as shown in Fig. 7 (a), the connecting member 4 having the shear connector 13 is connected through the connecting plate 12 to be bonded with concrete, and then shown in Fig. 7 (b). As shown, the abdominal member 4 is coupled with the concrete lower chord 14 and the concrete upper base plate 15, and the space between the concrete upper base plate 15 and the abdominal member 4 is filled with the abdominal concrete 16. To make a composite girder that performs the structural behavior of the beam. At this time, the concrete lower chord due to the external load is introduced by using the high-strength PS steel material 17 embedded in the concrete, the preceding compression force (P) is introduced.

8 shows a construction procedure of a composite girder according to a second preferred embodiment of the present invention. The composite girder according to the present invention may be manufactured using only a steel skeleton structure composed of only the abdominal member and the upper chord when the composite girder has a temporary condition in which the bulkhead can be placed by a crane before synthesis. First, as shown in FIG. 8 (a), the connecting

plates

10 and 12 are welded to the unit member 2 of a predetermined shape to form a plurality of members, and a shear connecting member (c) is used to couple the members to the concrete floor plate. 13) weld the upper chord (longitudinal beam, 8) of the steel material and the abdominal member to produce a steel skeleton structure. Next, as shown in FIG. 8 (b), the concrete lower chord 14 which introduces the precompression force P using the high-strength PS steel 17 embedded therein in the ground space separately formed therein. Combining the abdominal concrete (16) to produce a composite girder. Then, the manufactured housing girders are mounted on the pier or pillar using a crane, and the mounted housing girders and the concrete upper plate 15 are synthesized to complete the composite girders (FIG. 8 (c)).

9 shows a construction procedure of a composite girder according to a third preferred embodiment of the present invention. The composite girder according to the present invention has a long span or difficult to use large cranes, and if it is not possible to install it in the construction sequence as shown in FIG. And all of the lower chords are to be provided. First, as shown in FIG. 9 (a), the connecting plate 10 is welded to a predetermined shape of the unit member 1 to form a plurality of members, and the shear connecting member 13 for the coupling between the member and the concrete bottom plate. Top chord (long beam, 8) and bottom chord (long beam, 9) are welded to the abdominal member, respectively, to fabricate the steel skeleton structure. Next, as shown in FIG. 10 (b), the steel frame structure is mounted on a pier or column using a crane, coupled to the concrete lower chord 14, and the high-strength PS steel 17 embedded in the concrete lower chord 14. Introduce the preceding compression force (P) using. Then, as shown in FIG. 10 (c), the upper chord 9 of the steel frame structure and the concrete upper plate 15 are synthesized, and the abdominal member 1 of the steel frame structure, the concrete lower chord and the concrete upper floor are synthesized. Filling the empty space surrounded by the plate with the abdominal concrete (16) to complete the composite girder.

Embodiments according to the present invention described above may be modified in various forms, the scope of the present invention should not be construed as being limited to the embodiments described above. In addition, the terms used to describe the embodiments of the present invention are used for the purpose of describing the present invention and are not used to limit the scope of the present invention as defined in the claims or the claims.

The main effects of the composite girder according to the present invention are as follows.

First, it is possible to simplify the gap structure where the abdominal member and the upper chord or lower chord meet each other, thereby greatly improving workability and maintainability.

Secondly, the absolute magnitude of the axial force applied to the abdominal member is reduced, so that the specification of the abdominal member used even when used in the structure of the long span can be 2 to 3 or less, so that the product can be easily purchased and the production efficiency of the steel member is also improved. .

Third, by having a pattern of various shapes in the abdominal space it is possible to build a composite girder structure excellent in aesthetics to feel a new sense.

Fourthly, the advantages of truss structure and beam structure, and the advantages of steel and concrete can be properly combined according to the construction conditions and construction stages, thus enabling the construction of a composite girder structure that satisfies the economics and the constructability at the same time.

Claims

It has a skeleton structure of steel having a double member formed by connecting the steel members of a predetermined shape side by side through the bending process,

The lower part of the skeleton structure is coupled with the concrete lower chord introduced by the preceding compression force, the upper part of the skeleton structure is coupled with the concrete upper plate, the abdominal member and the concrete lower chord of the skeleton structure, and the abdominal member of the skeleton structure and Each abdominal space surrounded by a concrete top plate is filled with concrete, and finally a composite girder characterized in that the structural behavior as a beam (beam).
The method of claim 1,

The composite girder, characterized in that the steel member has a continuous pattern formed of only the unit member of the same shape made of circular or heart-shaped or inequality or semi-circular shape.
The method of claim 1,

The composite girder, characterized in that the steel member has a continuous pattern formed by combining the unit members made of at least two of the circular, heart-shaped, inequality arc-shaped, and semi-circular shape.
The method of claim 1,

Composite steel girder, characterized in that the steel frame structure is composed of only a plurality of members formed of unit members manufactured in the shape of a circle or heart or inequality or semicircle.
The method of claim 1,

The steel frame structure is provided with a longitudinal member on the upper part of the abdominal member formed of unit members made of circular or heart-shaped or inequality or semi-circular shape, and a longitudinal beam welded with a shear connector for the composite behavior with the concrete deck. The composite girder characterized by the above.
The method of claim 1,

The steel frame structure is provided with a longitudinal beam on the upper and lower portions of the abdominal member, in which a longitudinal connecting member for welding the composite member and the concrete member formed of unit members manufactured in a circular or heart shape or an inequality or semi-circular shape is welded. Composite girders characterized in that to independently resist the external load.