JPS59173470A - Brace structure and earthquake-proof wall having brace mounted therein - 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 The present invention provides a method for installing a column or beam of a steel frame structure, or a column or beam of a reinforced concrete structure, a steel reinforced concrete structure, or a precast reinforced concrete structure (hereinafter collectively referred to as a "concrete column or beam") between nodes. The yield stress l/ By applying an initial tension of about 2 or more with the necessary surplus strength until the yield stress, it has high yield strength and excellent toughness.
To provide an economical, easy-to-construct, and rational frame that does not cause buckling of places or damage to shear walls even when subjected to large horizontal loads due to earthquakes, typhoons, etc.

To deal with horizontal loads caused by earthquakes, wind, etc., it is effective to provide places A, O, and BD between the nodes of columns AD, Be, beam AB, and 2 ko, as shown in Figure 1 (Q). However, in general, steel places such as shaped steel, steel bars, and steel strips have a smaller cross section and a higher slenderness ratio than columns and beams, so
As shown in Figure (b), when the frame receives a horizontal load Pi, the contraction-side place m buckles immediately against the compressive load and becomes ineffective. Therefore, this is not the case unless a section steel or steel pipe with a large cross section is used for the place. Generally, the structural calculation is carried out by ignoring the total proof stress of the place kO on the contraction side and assuming that only the tensile force of the place 2 on the extension side is valid, and the cross section of the place etc. is determined and designed so that the tensile force is below -:p10osθ. It is being said. However, since horizontal loads caused by earthquakes and wind are dynamic loads that are applied repeatedly in positive and negative directions, tensile and compressive loads are applied to the place repeatedly, alternating with each other. If local deformation occurs, the strength of the structure against repeated horizontal loads will drop sharply, as shown in the history curve showing the relationship between load P and displacement δ in Figure 1 (0). That will happen. The so-called ``restoring force characteristics'' are poor, making it difficult to absorb earthquake energy effectively, and the ``toughness'' of the building is low. Furthermore, as mentioned above, only one bushing on one side is effective, so the rigidity of the frame is low, and the building is susceptible to shaking due to earthquakes, wind, etc.

Furthermore, the structure in which this steel place is built into a concrete earthquake-resistant ffl has exactly the same drawbacks as above, and also has the following drawbacks. In other words, (a) Concrete is harder and more brittle than steel, so although it has high initial usability, even slight deformation causes cracks to occur and reaches the maximum yield strength.If the deformation progresses further, the cracks expand and the yield strength rapidly decreases. decreases. Compared to that, steel walls have much lower rigidity, so the concrete shear wall will develop large cracks and collapse before it reaches a sufficient amount of deformation to fully demonstrate its tensile strength.

Also, when the steel place buckles due to compressive force, the force that tries to protrude out of the ivy frame structure works, pushing out the cover concrete and causing it to fall off.

The present invention has been devised to eliminate all of the above-mentioned drawbacks, and the first invention will be described in detail below with reference to schematic drawings.

Figure 2 (a) is a graph showing the relationship between tensile stress T and strain (elongation) ε of Wi-made place material;
), both places have a yield stress of 1 of Ty.
An initial tension T6+, which leaves the necessary surplus force up to the yield stress T, is applied at approximately /2' or more.

That is, due to this initial tension, the columns AD, lIC- and the beam E
- are T'i, , sinθ and T, respectively. COSθ
A compressive axial force of If this frame receives a horizontal load p'l, as shown in Fig. 2(b), the tensile force at the extension side place BD increases to 'p, -To+ΔT, whereas the tensile force at the contraction side place station - increases. decreases to T
2-T3-ΔT. The increase/decrease in this tensile force is ΔT-2
×oo8θ 1/2 of the above T-P/co day θ;
h, not only the increase in the tensile force of the extension side place... but also the decrease in the tension of the contraction side place m, T, will increase the horizontal strength of the frame as if the compression place were stretching and resisting by ΔT. Therefore, if we list the features of this frame, we can see that: 1) Both places work equally effectively, so economical design is possible, and the rigidity of the frame is similar to that shown in Figure 1. This is 21 times the case, and the shaking of buildings caused by earthquakes and typhoons is halved.

2) For earthquakes and typhoon loads that would normally occur,
Tensile force of l place TI1. Surrendered all T2 9 months; 7
14. Yo.

ΔT≦Tb j! IJchiT2; -Tmu・-ΔT
By designing so that ≧0, no compressive force is applied to the contraction side place, and buckling does not occur.

6) On the other hand, the tensile force T1°L on the extension side place correction may exceed the yield stress T) at the above maximum load; it may exceed -i and enter the plastic deformation region slightly, but even in that case, the yield stress or higher will be maintained. If the external force is removed, the yield strength will not decrease, and will return to its original state with a residual strain (elongation of the place) corresponding to the plastic deformation, as shown by the line ah in Figure 2. This residual strain is very slight, and it is not enough to affect other parts, but if you retighten only this stretched part, it will be completely restored to its original state with initial tension, and that work is easy. Can be done.

4) The history curve showing the relationship between the load P and displacement δ on the structure due to repeated horizontal loads has a spindle shape as shown in Figure 2 (0).
1. It can be seen that it can effectively absorb earthquake energy and has excellent restoring force characteristics.

5) By using a place frame, the building will not sway even in the event of an earthquake or typhoon that is normally considered, and will maintain a comfortable living environment, even if an unprecedented earthquake occurs. Since the place does not undergo compression buckling and has a restoring force, it does not leave any damage to the building, ensuring safety and reducing repair costs. And since all the places work effectively, it is durable, economical, and easy to construct.

6) It is an earthquake-resistant and wind-resistant structure that can be used in a wide range of applications, from super high-rise buildings to general, medium-rise buildings.

7) Since no compressive force is applied to this place, its cross-sectional shape can be freely chosen as long as it has the necessary cross-sectional area to withstand the tensile force, and any steel material can be used. Materials other than steel may be used if available, but among them, PC steel and Pam twisted steel (:P
C! cables) are considered to be optimal from a structural point of view, fit well in the design, and are economical and easy to use.

As an example, Fig. 3 shows a joint between a PC steel bale place and a steel column/beam.

8) The above describes the case where a small number of races are arranged in an X-shape within a unit frame of columns and beams as the most basic form, but since actual buildings will have multiple layers and multiple spans, Figure 5 (C) and As shown in the frame diagram 5 in FIG. 6, the places can be arranged so as to connect the nodes of the columns and beams through two layers or two spans or more multi-layers or multi-spans.

The second invention is one in which this steel place is built into a shear wall made of reinforced concrete or precast reinforced concrete, and is basically the same as the first invention. Since it has all the structural features, I will omit the explanation of these points completely, but by working with concrete shear walls, the following synergistic effects can be achieved. 1) Introducing initial tension to the steel place. By,
Concrete - Prestress is applied to the shear wall and concrete columns and beams in both vertical and horizontal directions within the frame, and the concrete shear wall is strongly tightened from all four circumferences, so even if the frame is subjected to shearing force, tensile or bending load. When cracks occur in the concrete, the shear resistance of the concrete shear wall increases in proportion to the compressive force.

2) The restraint delays and reduces the occurrence of cracks in concrete, and in the process of interstory deformation, it is possible to delay the time at which the concrete shear wall exerts its maximum bearing capacity and bring it closer to the point at which the steel place reaches its yield load. Note that the maximum strength of both can be synergized well.

3) Even after the concrete shear wall has reached its maximum strength, strong restraint from all four circumferences will prevent a sudden drop in strength due to the expansion of cracks and the peeling and collapse of the cracked parts. Because it does not allow it to grow,
◇ 5) Concrete shear wall structures surrounded by these columns and beams will not be damaged due to extrusion of the prisms and races caused by compression buckling and the concrete will not be pushed out of the plane. Improved performance can be seen as equivalent to the difference between prestressed reinforced concrete structures and regular reinforced concrete structures, from preventing and reducing cracks, increasing the shear strength and bending strength of the structure, to improving toughness and ultimate strength. A wide range of improvements can be expected.

6) The type, cross-sectional shape, and material of the place are free as mentioned above, but in order to incorporate it into concrete columns/beams and earthquake-resistant walls, it is necessary to attach and insulate high-g 4 degree steel PC steel shells and PC chain strands. A suitable method is to bury an unbonded tendon covered with concrete and then tension it after the required strength is achieved after pouring concrete to introduce tensile force into the place.

7) As mentioned above, in addition to the X-shaped arrangement of columns and beams within a unit frame, places can also be arranged in multiple layers or through multiple spans, but in the case of shear walls, the terminals of built-in places are not necessarily It is not necessary to connect to the nodes of the columns and beams; for example, a summer arrangement that connects the midpoint of the column height and the beam span as shown in Figure 4 C6) is effective. The reason for this is that when a concrete shear wall cracks and fails due to a large horizontal shear force, the surrounding columns and beams are generally pushed from the inner shear wall and bend outward, but inside the columns and beams If you connect the points with a place and apply strong tension, you will not only restrain the deformation of the columns and beams, but you will also introduce prestress by tightening the concrete shear wall strongly in both vertical and horizontal directions from the central force of the four sides. It is extremely effective in preventing cracks and increasing shear strength, thereby improving the performance of earthquake-resistant walls. This is similar to how summer-shaped diagonal arms serve as shear reinforcement for columns.

This shear wall with built-in braces arranged in a summer shape can be used alone, but it can also be easily used in multi-layer, multi-span frameworks as shown in Figure 4 (0)).

8) Other layout shapes for built-in places include V-shape, △-shape and their combinations as shown in Figure 5 <a) CO><c> of the frame diagram, and double-shape as shown in Figure 6. On the other hand, there are various combinations of types available, and all of them improve the performance of concrete shear walls by introducing initial tension, so they can be used depending on each case.

[Brief explanation of drawings]

Figure 1 (cl) ('b) (0) are respectively ! Showing the shape of the general frame placed in the iX type of place made by i, the relationship between deformation against horizontal load and place tensile force, and the history curve,
Figures 2 (a), (b), (Q) and @) respectively show the initial state of the frame of the present invention with initial tension applied to the steel place;
Relationship between deformation and place tension when subjected to horizontal load,
FIG. 6 shows an example of a place joint, and FIG. 4 (cL) and (b) show a frame in which places are arranged in a summer shape. Figures 5 and 6 show the frame diagram of the shape of the frame and the shape of the frame, and Figures 5 and 6 show the frame diagram of the frame arrangement type.

Claims (1)

[Claims] l. By applying an initial tension in advance to the steel places provided between the nodes of the columns and beams, which is about 1/2 or more of the yield stress and with a necessary surplus up to the yield stress, the frame can be constructed. When subjected to a horizontal load due to an earthquake, etc., not only the tensile force of the extension side place but also the reduced tension of the contraction side place is applied to the horizontal strength, and even at the maximum horizontal load, the compressive force is applied to the contraction side place. A place structure that prevents this from occurring. 2. In the initial stage, a steel place built into a shear wall of a reinforced concrete structure or a precast reinforced concrete structure surrounded by columns and beams is left with the necessary surplus to reach the yield stress at 1/g iM degree or more of the yield stress. By applying tension, when the frame is subjected to a horizontal load due to an earthquake, etc., only the tensile force of the extension side place can be applied, and the reduction in tension of the contraction side place can also be applied to the horizontal strength, and at the maximum horizontal load. A shear wall with a built-in place prevents the generation of compressive force on the contraction side place.