JPH04120331A - Joint construction for steel framed reinforced concrete column - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a joint structure for steel reinforced concrete columns that can save labor and reduce costs.

[Prior art and the problem to be solved by the invention] In the construction of high-rise steel-framed reinforced concrete houses, the floor height is low and the shear-span ratio is small, so the column side materials are of the type that precedes shear failure.

Especially Adhesive Warikka II! (When steel-framed reinforced concrete is subjected to bending or shearing forces, this often causes fractures in which the concrete splits along the main reinforcing bars and steel frames because the concrete is attached to the main reinforcing bars and steel frames.) In order to prevent this bond splitting failure, it is effective to make the cross section of the steel frame as small as possible for columns with a given cross section and increase the thickness of concrete covering the outer periphery of the steel frame, and by doing this, the cost will be reduced by the reduction in the number of steel frames. There is also the advantage of being able to do so.

In the above-mentioned architecture, the joints of steel-framed reinforced concrete columns using cross steel frames have traditionally been constructed by butting the edges of the upper and lower cross steel frames, and applying joint plates that span both steel frames to the flange and web portions of the upper and lower steel frames. The parts are tightened by machine using special high-strength bolts, and the web part cannot be used due to the narrow space.
It is joined by hand-tightening with high-strength bolts.

However, in the current era of labor shortages, manual tightening of high-strength bolts is extremely inefficient, and there has been a demand for streamlining this process.

The present invention has been made in view of the above-mentioned conventional problems and has been made with the objective of achieving this rationalization, and an object of the present invention is to provide a joint structure for steel-framed reinforced concrete columns that can simplify the joining of web portions. There is.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a butt joint of a steel reinforced concrete column using a cross steel frame, in which the flanges of the upper and lower steel frames are bolted together by applying a joint plate that spans both steel frames, and the web part of one steel frame is connected by bolts. It is characterized by a steel reinforced concrete column joint structure in which shear keys are planted and column concrete is cast, and stress is transmitted from the upper steel frame to the lower steel frame via the concrete section within the cross steel core.

[For production]

A shear key is installed in the web part of the upper and lower cross steel frames, and the shear stress of the upper and lower steel frames is transmitted through the concrete inside the cross steel core surrounded by the outer periphery of the cross steel frames. This eliminates the need to connect the joints of the web parts, which were previously bolted together, resulting in significant construction labor savings and cost reductions.

〔Example〕

The present invention will be described in detail below based on an illustrated embodiment.

In Figures 1 and 2, 1 is a steel reinforced concrete column, 2 and 2' are upper and lower steel frames using cross steel frames,
2a, 2a', 2b, 2b' are the flanges and webs of the upper and lower steel frames 2, 2・Both steel frames 2, 2' have their edges abutted, and the flanges 2a, 2a' have both steel frames on their inner and outer surfaces. Apply the joint plate 3 spanning 2° 2', insert the special high-strength bolt 4 into the bolt hole, and mechanically tighten it to join.A sear key 5, 5' is planted. The shear key 5 may be a stud bolt as shown in FIG. 3, or a bolt with a welded plate as shown in FIG. 4. In the figure, 6 and 7 are the main column reinforcements and hoops that were reinforced after the steel frame was assembled, 8 is the column concrete that was poured after the reinforcement was placed, and 9 is the concrete part inside the steel core surrounded by the outer periphery of the cross steel frame, which is similar to the conventional web. This is the concrete part that transmits the shear force of the steel frame instead of the joint plate, and this area does not participate in bond splitting failure.

In the joint structure described above, the shear stress of the upper steel frame 2 is as follows: upper steel web 2b → shear key 5 of the upper steel web → concrete part 9 in the steel core → shear key 5 of the lower steel web
' → is transmitted to the lower steel web 2b'.

That is, the shear stress of the upper steel frame 2 is transmitted to the lower steel frame 2' through the concrete part 9 in the steel core that does not participate in cohesive splitting failure.
Since the adhesion splitting capacity of the reinforced concrete part does not decrease, the relationship of Qu (ultimate shear capacity of the steel reinforced concrete column) = rQsu (adhesion splitting capacity) + Qp (inching capacity of the concrete in the steel core) is It will be established.

Here, if Qp (of the concrete in the steel core) (inching strength) < Qs (shearing strength of the steel web), the fifth
As shown in the figure, the concrete part 9 inside the steel core of the joint part
Insert dowel reinforcing bars 10 to increase the shear strength of the joint.

Further, since the steel frame webs 2b and 2b' are not directly joined, the bending strength of the steel frame decreases, but there is no problem because the joint portion is provided at a position close to the recursion point of the column.

In addition, if high stress is applied to the joint, the steel web 2
The abutting portions of b and 2b' are brought into close contact with each other without leaving a gap to form a metal touch joint.

〔Effect of the invention〕

As explained above, in the butt joint of a steel-framed reinforced concrete column using a cross steel frame, the flanges of the upper and lower steel frames are bolted together by applying joint plates that span both steel frames, and the webs of both steel frames are joined with shear keys. By planting column concrete and placing column concrete, and transmitting stress from the upper steel frame to the lower steel frame through the concrete part within the cross steel core, conventional bolt connections were made by hand tightening through joint plates. This eliminates the need for joint joining of the web parts, resulting in significant labor savings and cost reductions in construction.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional view of a steel reinforced concrete column that employs the joint structure of the present invention, and FIG. 2 is a cross-sectional view taken along the line A-A in FIG. FIG. 3 is an enlarged view of the shear key with the stud bolt, FIG. 4 is an enlarged view of the shear key with the cotter, and FIG. 5 is a plan cross-sectional view of the joint reinforced with dowels. ■...Steel reinforced concrete column, 2,2'...Steel frame,
2a, 2a'-flange, 2b, 2b'-web, 3.
...Joint plate, 4...Bolt, 5...Sea key, 6...
・Resident main frame, 7... Hoop, 8... Pillar concrete, 9
・・Concrete part inside the steel core, 10・・Dowel reinforcement. Diagram

Claims (1)

[Claims] At the butt joint of a steel reinforced concrete column using a cross steel frame, the flanges of the upper and lower steel frames are bolted together using joint plates that span both steel frames, and shear keys are planted in the webs of both steel frames and the column concrete is poured. A joint structure for a steel reinforced concrete column, characterized in that stress is transmitted from an upper steel frame to a lower steel frame via a concrete section within a cross steel core.