JPH0749693B2 - Prefabricated composite girder and composite girder support structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a prefabricated composite girder composed of a steel girder and a prefabricated concrete panel, and a support structure for the prefabricated composite girder.

[Conventional technology and its problems]

Conventionally, prefabricated composite girders that combine steel girders and concrete panels have been used for the floor structure of buildings, roads, multistory parking lots, and other structures. Such a composite girder is required to have a sufficient supporting strength against a load and a fixing structure for firmly connecting a steel girder with different properties to a concrete panel.

However, the conventional prefabricated composite girder has a drawback that it takes a long time to construct because it has a structure in which a gibber is provided on the upper surface of a steel girder and then a concrete panel is placed and connected.

As a solution to such drawbacks, Japanese Patent Publication No. Sho 53-2604
There is a prefabricated composite girder proposed in No. 8 publication. In this composite girder, a large number of dowels are provided on the upper flange of the steel girder, and the joint concrete is filled between the prefabricated concrete panels provided on both sides of the dowel, and the joint concrete and the dowel form the panel. It has a structure in which steel girders are integrally connected.

However, in the above proposed structure, when the composite girder is formed by on-site construction, the joint concrete filled between the panels requires a curing period, which requires a lot of labor and time for construction, resulting in work efficiency. It has the drawback of being bad. Further, since the steel girder and the panel are integrally connected by the joint concrete, it is difficult to disassemble the girder and partially replace it, which is troublesome.

On the other hand, when a load is applied to a simple beam, compressive stress is generated on the upper surface of the deforming beam and tensile stress is generated on the lower surface.
In the composite girder, a concrete panel that is strong against compression is placed on the upper side, and a steel girder that is strong against tension is placed on the lower side to form a beam structure with high rigidity. However, when the composite girder receives a static load and bends downward, and if a fluctuating load is further applied on it, the composite girder bends significantly, causing a positional shift between the steel girder and the concrete panel. There was a drawback that the bond of was easily broken. In particular, floor structures such as roads and multilevel parking lots are subject to static loads and fluctuating loads due to the movement of cars, etc., so the composite girders used have sufficient strength against fluctuating loads. Structure required.

[Object of the Invention]

The present invention is difficult to solve the above-mentioned drawbacks of the conventional structure, and a first object thereof is to firmly bond a steel girder and a panel in a short time without using a dowel or joint concrete, and It is to provide a prefabricated composite girder that can be easily disassembled and partially replaced.

A second object is to provide a support structure for a prefabricated composite girder having a sufficient support strength against a fluctuating load applied together with a static load.

[Means for achieving the purpose]

In order to achieve the above first object, the present invention provides a groove having an inverted V-shaped cross section extending in the length direction of the steel girder on one of the joint surfaces of the steel girder upper surface and the concrete panel, and on the other. A structure is adopted in which a projection that engages with the groove is provided, and a tightening bolt that tightens both the steel girder and the concrete panel is provided along the groove and the projection.

The tightening bolt may be provided only in the vicinity of the support end of the steel girder.

In addition, in order to achieve the second object, in the structure in which both ends of the prefabricated composite girder having the above-described structure are supported, the prefabricated composite girder is supported with the center portion of the prefabricated composite girder bent upward with respect to both ends. It adopted a structure that does.

[Action]

As shown in FIG. 1, when the inverted V-shaped groove a and the protrusion b are engaged with each other and a vertical tightening force F is applied between them, the joint surface between the groove a and the protrusion b is The wedge effect produces a crimping force Fc that is a multiple of the clamping force F. The crimping force Fc is, for example, about 3 times the tightening force F when the V-shaped angle α is 40 degrees, and about 4 times the tightening force F.

By applying the pressure bonding force Fc to the joint surface between the groove a and the protrusion b in this way, a large frictional force is generated on the joint surface, and the positional deviation occurring in the length direction of the groove a between the joint surfaces is prevented. . Further, the positional deviation in the direction perpendicular to the length direction is stopped by the engagement of the groove a and the projection b.

On the other hand, in the composite girder support structure of the present invention, the composite girder is supported in a state of being bent upward in advance, and when a large fluctuating load is applied, the composite girder deforms downward,
The steel girder and concrete panel are set so that appropriate amounts of compression and tension occur. As a result, the composite girder maintains its deformation within a range in which displacement or floating does not occur even when a fluctuating load is applied, and thus there is a margin of deformation with respect to the applied load.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In the embodiment shown in FIGS. 2 to 4, reference numeral 1 is a well-known steel girder made of I-type steel, on the upper surface of the upper flange 1a thereof,
The steel girder 1 is provided with protrusions 2 and 2 having an inverted V-shaped cross section, which extend in the length direction. The protrusions 2 and 2 are arranged parallel to each other and are integrally formed over the entire length of the steel girder 1 in the length direction.

Further, a plurality of bolt insertion holes 3 through which the tightening bolts 6 are inserted are formed on both sides of each of the protrusions 2 and 2.

On the other hand, 4 is a prefabricated concrete panel, and this panel 4 is placed facing each other on both sides of the upper flange 1a of the steel girder 1. On the lower surface near the side edges of the panels 4 and 4,
Corresponding to the protrusions 2 and 2 of the steel girder 1, an inverted V-shaped groove 5 that engages with the protrusions 2 and 2 is formed. Also, the grooves 5, 5
A nut 7 for screwing the tightening bolt 6 is embedded in both sides of the steel girder corresponding to the bolt insertion hole 3 of the steel girder 1.

As shown in FIG. 2, the prefabricated composite girder having the above-described structure has concrete panels 4 and 4 mounted on both sides of the upper flange 1a of the steel girder 1 with the grooves 5 and the projections 2 formed thereon.
The tightening bolt 6 inserted through the insertion hole 3 is screwed into the nut 7, and the panel 4 and the steel girder 1 are tightened to form. Due to the tightening of the tightening bolt 6, a large crimping force is generated on the joint surface between the groove 5 and the protrusion 2 due to the wedge effect as described in the section of action, and therefore, the frictional force acting on the joint surface causes the horizontal direction. Is prevented from being displaced, and a stable connection state between the steel girder 1 and the panel 4 can be obtained.

FIG. 5 shows another embodiment. In this structure, an inverted V-shaped projection 11 is provided at the center of the upper surface of the steel girder 10. Also, on the sides of the panels 12, 12, overlapping each other
Overhangs 13 and 14 having the same thickness as that of 12 are provided, and an upper and lower surface of one of the overhangs 13 has an inverted V-shaped projection 15 and a groove extending in the length direction of the steel girder 10, respectively. 16 is formed, and an inverted V-shaped groove 17 is formed on the lower surface of the other protruding portion 14.

Further, on one side of the panel 12 and the upper flange 10a of the steel girder 10, a plurality of bolt insertion holes 19 and 20 are formed along each protrusion and groove.

In the above structure, the protrusions 13 and 14 of the panels 12 and 12 are provided on the upper flange 10a of the steel girder 10, the protrusions 11 and 15 and the grooves 16 and 17 respectively.
Are engaged and overlapped with each other, and the panel 12 and the steel girder 10 are tightened and fixed by the tightening bolts 18 and nuts 21 attached to the insertion holes 19 and 20.

On the other hand, FIG. 6 shows an embodiment of a composite girder support structure. This support structure supports both ends of the steel girder 1 of the prefabricated composite girder A described in FIG. 2 between the struts 22 and 22, and pushes up the central part of the lower surface of the steel girder 1 with the support work 23 to synthesize it. The center part of the girder A is supported in a state of being bent upward.

The bending size of the composite girder A is such that when the fluctuating load is applied together with the static load, the composite girder A bends downward, and the tensile and compressive stress generated in the concrete panel 4 and the steel girder 1 are within an appropriate range. It is set to enter.

By the way, in the support structure shown in FIG. 6, the spacing between the tightening bolts 6 of the composite girder A is small in the vicinity of the supporting end portion of the support column 22 and is large in the central portion. This is because when the double-structured composite girder A is bent, the panel 4 for the steel girder 1
Since the displacement amount of is small in the central part and is largest in the supporting end part, the panel 4 and the steel girder 1 at the supporting end part with large displacement amount are
This is based on the reason that if the girders are securely fixed so that they do not move, it is possible to prevent the displacement of the girders as a whole.

For this reason, if the amount of deformation of the composite girder with respect to the applied load can be suppressed within a range that is relatively smaller than the allowable value, fix only the both ends of the composite girder with the tightening bolts, and omit the tightening bolt in the central part. You can also In this case, depending on the distribution of the tightening bolts, the projections 2 and the grooves 5 on the panel 4 and the steel girder 1 may be provided only in the vicinity of the support end of the composite girder A.

In addition, in the above-described embodiment, the structure in which the protrusion is provided in the steel girder and the groove is provided in the panel is shown, but this arrangement may be reversed.

Further, the protrusion and the groove do not have to be continuous in the length direction of the steel girder as in the embodiment, and may be provided in a discontinuous state along the length direction.

Furthermore, the projections and grooves do not have to be formed integrally with the steel girder or the panel, and may have a structure in which, for example, an engaging member having the projections or grooves is detachably mounted.

〔The invention's effect〕

As described above, the composite girder of the present invention is provided with a groove and a protrusion that engage with each other between the steel girder and the panel, and a wedge effect is generated between the groove and the protrusion, so that a large crimping force is applied to the joint surface. As a result, the positional deviation between the steel girder and the panel can be effectively prevented. Therefore, there is no need to use a dowel or joint concrete, and the curing of the concrete is not required, so that there is an effect that work efficiency can be greatly improved. Further, since the panel and the steel girders are mechanically connected by the tightening bolts, there is an advantage that the girders can be easily disassembled and partially replaced.

Further, according to the composite girder support structure of the present invention, by applying a preload to the composite girder in a direction opposite to the load direction, the composite girder can be kept in a high rigidity state even when a fluctuating load is applied, It is possible to provide an optimal support structure for a floor structure such as a road or a multistory parking lot.

[Brief description of drawings]

FIG. 1 is a schematic view showing the operation of the present invention, FIG. 2 is a vertical sectional front view showing an embodiment of a prefabricated composite girder, FIG. 3 is a perspective view showing a steel girder of the same, and FIG. 4 is a concrete panel of the same. FIG. 5 is a vertical sectional front view showing another embodiment, and FIG. 6 is a side view showing an embodiment of the composite girder support structure. 1, 10 ... Steel girder, 2,11,15 ... Protrusion, 4,12 ... Concrete panel 5,16,17 ... Groove, 6,18 ... Tightening bolt, 7,21 ... Nut, 22 …… Posts, 23 …… Supporting work, A …… Prefabricated composite girder.

Claims (3)

[Claims] 1. A prefabricated composite girder for supporting and supporting a prefabricated concrete panel on the upper surface of a steel girder, wherein one of the joining surfaces of the upper surface of the steel girder and the concrete panel has a cross-section reverse to the longitudinal direction of the steel girder. A prefabricated composite, characterized in that a V-shaped groove is provided, a protrusion engaging with the groove is provided on the other side, and a fastening bolt for fastening both is provided between the steel girder and the concrete panel along the groove and the protrusion. digit. 2. The prefabricated composite girder according to claim 1, wherein the tightening bolt is provided only in the vicinity of the support end of the steel girder. 3. A prefabricated composite girder supporting structure for supporting both ends of the prefabricated composite girder according to claim 1 or 2, wherein the prefabricated composite girder is bent upward with respect to a central portion of the prefabricated composite girder. Prefabricated composite girder support structure characterized by supporting the girder.