JPH0765381B2 - Beams with reinforced concrete ends and steel frames in the center - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a beam of a structure.

(Prior Art) In the Japanese Patent Application Laid-Open No. 61-233147, the present applicant consists of a central steel frame part and an end reinforced concrete part, and a steel frame of the central steel part is embedded in a part of the end reinforced concrete part. ,
By integrating both, the self-weight can be reduced compared to the conventional reinforced concrete beam, a long span beam can be constructed with a small beam construction, the degree of processing to secure the erection accuracy is significantly reduced, and the central steel frame and The rigidity of the beam can be adjusted by appropriately combining the cross-section of the end reinforced concrete part and the proportion occupied in the material axis direction, and when the horizontal force acts on the building by adjusting the strength of both parts. We proposed a beam in which the end of the central steel frame is yielded so that a structure with excellent toughness is constructed.

(Problems to be Solved by the Invention) The present invention uses a joining method different from the above-mentioned conventional technique to pull out the main bar of the end reinforced concrete part in which the central steel frame part is embedded and to break the concrete around the steel frame and the main bar. The purpose is to provide a beam that can be prevented from being reinforced concrete at the end and steel at the center.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the beam according to the present invention is such that a part of the main bar of the reinforced concrete part is welded to a steel frame embedded in the part and the other part is screwed. With a reinforcing bar, tightening the ends of the threaded rebar through the fixing plate and nuts on both sides of the steel frame part in the end face of the reinforced concrete part, and reinforcing bars around the steel frame and the main bar embedded in the reinforced concrete part. Alternatively, it is configured by surrounding a spiral PC steel material, and arranging the reinforcing bar or spiral PC steel material more densely than an intermediate portion at both ends of an embedded portion of the steel frame with respect to the reinforced concrete portion.

(Operation) In the beam according to the present invention, as described above, since a part of the main bar of the end reinforced concrete part is welded to the steel frame embedded in the part, extraction of the steel frame from the concrete part is prevented. The other part of the main bar is formed into a threaded reinforcing bar, and the ends of the main bar are tightened through fixing plates and nuts on both sides of the steel frame at the end face of the reinforced concrete part, so that the splitting of concrete around the main bar is performed. Is also prevented, and the spiral PC steel material is arranged over the main bar and the steel frame embedded portion, and the spiral PC steel material is arranged more densely than the middle portion at both ends of the reinforced concrete embedded portion in the steel frame. , The force is sufficiently transmitted from the steel frame part embedded in the reinforced concrete part at both ends to the reinforced concrete part, and the concrete Of destruction can be prevented.

(Examples) The present invention will be described below with reference to illustrated examples.

(A) is a central steel frame part made of H-shaped steel, the steel frame (1) of the same part is embedded in a part of the end reinforced concrete part (B), and both are integrated to form a beam. In the figure, (C) is a column made of reinforced concrete.

A part of the main bar (1) of the end reinforced concrete part (B) is welded to the flange of the embedded part (A ′) of the central steel frame part (A) in the part (B), and the other part is screwed. Reinforcing bars (1 ') are formed on both sides of the embedded portion (A') of the central steel frame portion (A), and end reinforced concrete portions (B)
The fixing plate (2) is fitted to the end threaded portion (1'a) passing through the nut, and the nut (3) is screwed and tightened.

Further, two sets of reinforcing bars or high bars are provided around the embedded portion (A ′) for the end reinforced concrete portion (B) in the central steel frame portion (A) and the main reinforcement (1) (1 ′) of the reinforced concrete portion (B). The strength-deformed spiral PC steel materials (4) are surrounded so as to be intertwined with each other. Thus, the reinforcing bar or spiral PC steel material (4) is arranged more densely than the intermediate part at both ends of the embedded part (A ') of the central steel frame part (A).

In the illustrated embodiment, as described above, the main bar (1) of the end reinforced concrete part (B) is welded to the flange of the embedded part (A ') of the central steel part (A) with respect to the part (B). This prevents the buried portion (A ′) from being pulled out from the reinforced concrete portion (B) at the end, and the main reinforcement (1 ′) of the portion (B) is located at the central steel frame portion (A) with respect to the portion (B). Since it penetrates to the end of the embedding part (A '), the reinforcing bar or spiral high-strength deformed PC steel bar (4) can be arranged over the entire length of the embedding part of the steel frame, and thus the central steel frame. The burying length of the part (A) with respect to the end reinforced concrete part (B) can be shortened.

Moreover, the main bar (1 ') is composed of a threaded rebar,
The fixing plate (2) is fitted to the end screw part (1a) penetrating the end reinforced concrete part (B), and the nut (3) is screwed and tightened, so that the adhesive cracking of concrete around the main bar is prevented. It can be prevented and there is no need to bend the ends of the main bars. The fireproof coating on the exposed portion of the steel material from the concrete can be performed at the same time as the fireproof coating on the steel frame, so the number of construction steps does not increase.

Further, two sets of reinforcing bars or high strength deformed PC spiral steel materials (4) are entwined with each other continuously over the entire length of the end reinforced concrete part (B) and the embedded part (A ') of the central steel frame part (A). Since the main bars are arranged so as to surround the main bars, the force is sufficiently transmitted from the steel frame portion to the reinforced concrete portion in the steel frame embedded portion (A '), and the destruction of concrete at this portion is prevented.

Further, since the reinforcing bar or the PC spiral steel material (4) is densely arranged at both ends of the steel-frame-embedded part (A ') where stress is most concentrated, destruction of concrete in the part is surely prevented. Is.

Next, test examples of the present invention will be described.

FIGS. 5 to 7 show the test piece (P), which is shown with a half size of the actual product, and the dimensions are expressed in mm.

The steel frame is 300 × 100 × 9 × 12 (mm) H-shaped steel, the main bar is 12 steel plates with a diameter of 19 mm, the spiral bar is a high-strength steel bar with a diameter of 7.4 mm, and the concrete is four-round strength Fc = 450 kg /
It was cm ² .

Thus, a test body was integrally produced in which the base (R) in which the vinyl chloride pipe (Q) was embedded was integrally provided on the base of the end reinforced concrete of the specimen (P), and the vinyl chloride pipe (Q) was manufactured. It is fixed to the reaction force floor (T) through the inserted anchor bolts (S), and the ball seats (U) provided on both side flanges of the steel frame portion of the test body are mounted on the reaction force floor (T) on both sides of the test body. As a result of performing a test by pressurizing with a horizontal jack (W) mounted on the fixed horizontal reaction force frame (V) (see FIG. 10 and FIG.
The load deformation curve as shown in Fig. 12 was obtained.

This load-deformation curve is similar to the bending-yield curve of the rebar of a beam of a general reinforced concrete structure, and because the embedded part of the central steel frame part at the end reinforced concrete part is not broken, it is excellent in deformability and can be repeatedly loaded. It has a proof stress.

(Effect of the invention) As described above, the end portion according to the present invention is made of reinforced concrete,
In a beam with a steel structure in the center, part of the main reinforcement of the reinforced concrete part was welded to the steel frame embedded in the same part, preventing extraction of the embedded part of the steel frame to the reinforced concrete part from the same concrete part. In addition, the other part of the main bar is composed of a threaded reinforcing bar, and is tightened via fixing plates and nuts on both sides of the steel frame part at the end face of the reinforced concrete part, thereby causing the adhesive split fracture of the concrete around the main bar. Since the threaded reinforcing bar penetrates to the end of the embedded part of the steel frame in the reinforced concrete part, the reinforcing bar in the reinforced concrete part or spiral PC steel material can be laid out over the entire length of the embedded part of the steel frame, and therefore the steel frame The burying length of the reinforced concrete part can be shortened, and the PC
Coupled with the fact that the spiral steel material is reinforced more densely than the middle portion at both ends of the embedded portion of the reinforced concrete portion of the steel frame where stress is concentrated, the force transmission from the steel portion to the reinforced concrete portion is sufficiently performed.

As described above, according to the present invention, it is possible to prevent the destruction of the central steel frame portion of the reinforced concrete at the end portion in the embedded portion.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a beam having a reinforced concrete structure at the ends and a steel frame structure at the center according to the present invention, FIG. 2 is a cross-sectional plan view thereof, and FIG. 3 is a longitudinal side view thereof. Fig. 4 is a longitudinal sectional view of a structure using the beam, Fig. 5 and Fig. 6 are the same as Fig. 7, and Fig. 7 is a transverse plan view of the test piece and a longitudinal sectional view is the longitudinal sectional side view. Fig. 8 is the test. Front view of the body, Figure 9 is its side view,
FIG. 10 is a front view of the test apparatus for the test body, FIG. 11 is a plan view thereof, and FIG. 12 is a load deformation curve obtained by the test. (A) …… Central steel frame (A ′) …… Embedded part of the central steel frame (B) …… End reinforced concrete part (1) (1 ′) …… Main bar, (1′a) …… Screw part ( 2) …… Fusing plate, (3) …… Nut (4) …… Reinforcing bar or high-strength deformed spiral PC steel

Claims (1)

[Claims] 1. A beam comprising a central steel frame portion and end reinforced concrete portions, wherein the steel frame of the central steel frame portion is embedded in a part of the end reinforced concrete portion to integrate the two, and one of the main reinforcements of the reinforced concrete portion is Weld the part to the steel frame embedded in the same part, and make the other part a threaded rebar, the ends of the threaded rebar through the fixing plate and nuts on both sides of the steel frame part in the end face of the reinforced concrete part. Along with tightening, surround the steel frame and the main bar embedded in the reinforced concrete part around the reinforcing bar or spiral PC steel material, the both ends of the embedded part to the reinforced concrete part in the steel frame are denser than the middle part of the reinforcing bar or spiral PC A beam made of reinforced concrete at the end and steel frame at the center, which is characterized by arranging steel materials.