JPS5817052Y2 - reinforced concrete column - Google Patents

Description

[Detailed description of the invention] This invention relates to a reinforced concrete column using steel fiber concrete.

High-rise buildings constructed of reinforced concrete have a large self-weight, and in order to plan for a building with sufficient toughness, high-strength concrete and high-strength, large-diameter reinforcing bars must be used.

In addition, it is desirable to reduce the cross-sectional dimensions of columns and other members in order to effectively utilize the plan. The column will be subjected to a large amount of tensile stress.

Generally, it is said that the toughness of the member cannot be expected when the axial compressive stress is one-third or more of the compressive strength of concrete, but members with reinforcement structures that combine square hoops and spiral reinforcements are made of high-strength ordinary concrete. and two-thirds of the compressive strength
Tests have shown that level 1 is sufficiently earthquake resistant.

However, if the building is higher-rise and the span of the beam is larger, it is necessary to use a material that has even higher concrete strength and is resistant to adhesion and tension.

This invention was devised to meet the above requirements, and its details will be explained below with reference to illustrated embodiments.

Figure 1 shows a cross section of the reinforced concrete column of this invention. ...... are arranged around the rectangular column cross section, and the column main reinforcements 1, 1 at the corners
, . . . are connected by square hoop reinforcements 2 as shear reinforcing reinforcements, and other column main reinforcements 1゜1, .
The spiral reinforcement 3 is used as a restraining reinforcing bar in the substantially circular part surrounded by 1, that is, the core of the cross section of the frame structure.

The parts where these column main reinforcement reinforcements 2 and spiral reinforcements 3 are arranged are made into an RC structure in which ordinary concrete 4 is poured, and the concrete at the core of the cross section of the frame is restrained by the spiral reinforcements 3 as restraining reinforcements. has a 5FRC (Steel Fiber Reinforced Concrete 5) structure with steel ivar mixed in.

By the way, when manufacturing the above columns, hollow precast reinforced concrete members were manufactured using ordinary concrete 4,
Concrete mixed with steel fibers can be poured into the central hollow part on site.

Another method is to prepare a precast concrete member mixed with steel fibers in advance, insert the precast concrete member into the spiral reinforcement 3 when assembling the reinforcing bars, and then pour ordinary concrete 4 around it on-site. You can also do it.

Figure 2 shows the load and deformation of a column with an acting axial force of N''140 tOn, and when the square hoop reinforcement 2 and spiral reinforcement 3 described above are combined and ordinary concrete is used for the entire cross section, CB l m B 2 ) and When concrete (concrete) K steel fiber at the core of the cross section of the cross section is made by S people, (AI
, A2. A3) is shown.

The band muscle mass Pw (volume ratio) of the square hoop muscle 2 and spiral muscle 3 is A1 s A2 s A3 and B 1 vc, respectively, P,, = 0.9q/), and for B2, Pw = This is section 1.2.

Further, the mixed amount (weight ratio) of steel fibers in A 1 s A2 s A3 is 2.0 ratio for A1, 1.5 ratio for A2, and 1.0 ratio for A3.

In addition, 2.0% steel fiber is added to the concrete.
If it is mixed in more than 1.0% (by weight), the workability will be poor as the steel fibers will get tangled and cannot be mixed evenly, and if it is mixed in less than 1.0%, no effect can be expected.

As is clear from the graph showing the actual results above, in the case of the reinforced concrete column of this invention (A1゜A2.A3), the same amount of stirrup Pw = 0.9qI) (volume %) and B2, which has the amount of tie reinforcement increased to Pw = 1.2%, it can be seen that the yield strength has increased by about 30% and that it can be expected to have sufficient tenacity during large deformations.

Therefore, the pillars of this invention can be made smaller in shear than ordinary ones, making it possible to construct taller buildings with the same dimensions as ordinary buildings.

In particular, by using steel fiber reinforced concrete with excellent toughness and bending tensile strength for the parts restrained by restraining reinforcing bars such as spiral reinforcement, it is possible to withstand the restraining force even in the event of an earthquake. As a whole, a synergistic effect can be obtained by fully utilizing the restraining effect of the restraining reinforcing bars.

Conversely, if the concrete in the part to be restrained is not reinforced, it will not be able to absorb the restraining force, and sufficient earthquake resistance will be obtained. Since there are no obstacles during installation, even pouring can be performed.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a column according to this invention, and FIG. 2 is a graph showing experimental results. 1... Column main reinforcement, 2... Hoop reinforcement, 3... Spiral reinforcement, 4... Concrete, 5... Steel fiber reinforced concrete.

Claims (1)

[Scope of utility model registration request] Column main reinforcements are connected with shear reinforcing bars, restraint reinforcing bars are arranged so as to surround the cross-sectional core of the cross-section, and steel fibers are mixed into the concrete of the cross-section core of the cross-section. reinforced concrete columns.