Bearing Walls And Connecting Members Therefor

Abstract

Reinforced bearing walls wherein the reinforcing is at least two steel sheets which have been previously bent, but when mounted are symmetrical along a center line in the bearing wall, and provisions for connecting the bearing walls to other structural members.

Description

This invention relates to variable, rigid and flexible bearing walls wherein precast concrete boards (hereinafter called as Pca board) are employed as bearing elements in a structural body. The Pca boards are erected on the surfaces of structural steel constructions, and the Pca boards and structural steel construction are structurally joined by means of connecting members

Buildings receive unimaginable strong horizontal forces on the occurrence of earthquake, severe wind and the like, which forces becomes stronger as the number of floors in building increase. Usually, safety of building against the horizontal forces as described above, has been provided by structural steel Rahmen (rigid frame) construction, structural steel truss construction or concrete wall bodies attached to such constructions, as just mentioned, and quake resistance and bearing elements by means such as braces.

With the recent increasing trend toward high and ultra-high buildings, and further toward prefabricated building, variations in the structural dynamics characteristics have been required relative to the construction of buildings, to provide necessary and sufficient bearing strength and rigidity, and further steadfastness and endurability against destruction. That is, it is ideal for a building to be in the form of soft construction, in which the horizontal force caused by earthquakes and the like is weakened by flexible deformation of the whole building.

However, since a standard building body hitherto has been constructed such that reinforced concrete walls are singly placed on the surfaces of the structural steel construction, the wall bodies have shearing rigidity extremely larger than that of the structural steel construction. Thus the wall bodies mainly control the rigidity of the building, and consequently allowance for horizontal forces in the rigid construction body has been affected by providing strong support of the building itself. For the aforesaid reasons, the forces applied are so strong that high and ultrahigh buildings could properly not withstand earthquakes. The dynamic characteristics for the reinforced concrete wall are as shown in FIG. 1, in form of graphs made by curves (A), (B) and (C). When the rigidity increases as shown, K.sub.1, K.sub.2, K.sub.3, the bearable force increases as shown, by .delta..sub.1, .delta..sub.2, .delta..sub.3, and both are inevitably in direct proportional relation. Thus it obtain individually desirable been difficult to have values relative to the bearing force or rigidity. Furthermore, said construction is too strong in rigidity to receive the horizontal load, having the disadvantage of lacking toughness, and is strictly speaking, not suitable for use in soft building construction.

In one layer truss wall construction, in which Pca wall boards may serve as both fire-proof convering and partitioning walls, boards are attached to both surfaces of a lattice member. In this construction each board occupies a considerable amount of dead spaces due to its construction form, and is uneconomical because two sheets of Pca wall board are required each mounted on both sides.

Various disadvantages in building construction, as above, hitherto encountered can be eliminated in accordance with the present invention.

One object of the invention is to provide a building construction provided with the characteristic of soft construction most suitable for a high and ultrahigh buildings.

Another object of the invention is to provide a flexible bearing wall having structural dynamic characteristics extremely useful for buildings in the form of soft construction, in which the bearable force of a wall body is fixed at a desired value, and on the other hand, the apparent rigidity of wall body can be varied freely, and established at its desired value.

Another object of the invention is to provide a bearing wall provided with the toughness necessary and sufficient for a soft construction, as well as, good flexibility.

Further, another object of the invention is to provide a variable rigid bearing wall, which is most suitable for prefabricated bearing wall construction, with less deadspace, and which can considerably reduce the quantity of steel to be used. Also an object is the provision of simple construction which can be completed in a short period of time with the improvement of working efficiency, thus to keep the unit price work is low.

Another object of the invention is to provide a special connecting member, which is able to vary, as desired, its yield strength, rigidity and toughness against the hroizontal load or shearing force, has sufficient yield strength against vertical loads, and which is effective in the manufacture of a variable rigid bearing wall having a good characteristics for soft construction.

Another object of the invention is to provide connecting member which is simple in construction and has a good workability, and which can be manufactured by mass production economically, is easily used, and which has versatile dynamic characteristics respondable in every way.

In accordance with the invention, the various drawbacks, as described above, can be eliminated with respect to the building construction hitherto available. As shown in curves (A'), (B') and (C') by graphs in FIG. 2, the structural dynamic characteristics may be extensively improved for high and ultrahigh buildings, enabling maintainance of a fixed bearable force, that is, .delta..sub.3, which is sufficient for the requirements, even if the rigidity is varied as in K.sub.1, K.sub.2 and K.sub.3.

Other objects and useful features of the invention will be evident from the accompanying drawings and a detailed description to be described hereinbelow.

In the drawings:

FIG. 1 is a graph showing the dynamic characteristic of the prior bearing walls;

FIG. 2 is a graph showing the dynamic characteristics of bearing walls according to the present invention;

FIGS. 3 and 4 are descriptive views showing arrangements of construction of the bearing walls according to the invention, shown by way of space diagrams;

FIG. 5 is a front view showing an embodiment of the bearing wall according to the invention;

FIG. 6 is a front view of an enlarged portion of circle VI shown in FIG. 5;

FIG. 7 is a sectional view taken along line VII - VII designated in FIG. 6;

FIG. 8(A), FIG. 8(B) and FIG. 8(C) are sectional views showing another embodiments of connecting member in a manner similar to FIG. 7;

FIG. 9 is an isometric view of a connecting member of the standard type;

FIG. 10 is an isometric view of another connecting member constructed by an idea different from that of the connecting member represented in FIG. 9;

FIG. 11 is a front view of the connecting member shown in FIG. 10, which is incorporated in a bearing wall, showing it by way of a partial view similar to FIG. 6;

FIGS. 12 and 13 are sectional views taken along lines XII -- XII and XIII-- XIII of FIG. 11;

FIGS. 14 to 16 are front views partly enlarged of another embodiments made on the basic of idea of the connecting member represented in FIG. 10;

FIGS. 17 and 18 are isometric views of connecting members constructed based on a further different idea;

FIG. 19 is a front view, partly enlarged, using the connecting member shown in FIG. 17;

FIG. 20 is a sectional view along line XX--XX designated in FIG. 19;

FIG. 21 is a front view partly enlarged, using the connecting member shown in FIG. 18;

FIG. 22 is a sectional view along line XXII-- XXII designated in FIG. 21; and

FIGS. 23 to 26 are isometric views of the other connecting members constructed by further developing the ideas of connecting members shown in FIGS. 17 and 18.

The invention will be described with reference to the accompanying drawings by way of embodiments.

Variable, rigid and flexible bearing walls according to the invention are roughly constructed as shown in the space diagrams of FIGS. 3 and 4.

That is, the circumference of Pca wall board 3, as a bearing element is provided with rectangular-shaped indentations, so that connecting members can be inserted therein, and anchor plates project into the indentations so as to be able to join structurally the connecting members at the bottom of the indentation. A Pca wall board is hung in the structural steel Rhamen construction formed by post 1 and beam 2, and joining of the Pca wall board and the steel structural construction is effected by means of the connecting members.

The joining by means of connecting members is affected all around the circumferences of Pca wall board 3 at regular intervals, and it should be so designed that each connecting member bears an equal load. With respect to the Pca wall board 3 and structural steel construction, it should be so designed as to be constructed on the assumption that as far as erecting work is carried on in accordance with the predetermined procedure and method, equal clearances in each section are formed in the circumference of each Pca wall board so as to leave room for shearing deformation allowed in the design.

In FIG. 5, a variable rigid bearing wall in accordance with the invention is shown as a model of one unit, in which each wall body construction is effected by erecting a precast wall board 3 on the surface of the structural steel Rhamen construction comprising posts 1 and beams 2, and a number of fine clearances are provided in the circumference of the wall board so as to be joined by a number of connecting members 4.

In order to understand the nature of the bearing wall according to the invention, the dynamic structural features and characteristics of the connecting member 4 must be described.

One example is shown in FIG. 9, in which a sheet of steel plate, such as an ordinary construction material, is worked so as to be bent to form a convex part 4a, projected in a rectangular shape. Upper and lower surfaces 4c, 4d, extending therefrom are provided with bores 4b for bolts formed close to the ends of the surfaces. This means that the concave part 4a has been constructed in a rectangular shape, whereby measurement Lo (Lo = a + 2b + 2c) ought to be very large, although the apparent length L is particularly small.

When considering the horizontal force acting in the X direction with respect to the dynamic characteristics, the elastic deformation of the connecting member produced by the horizontal force is equal to the algebraic sum the shearing deformation and bending torsional deformation. These deformations make measurement of forces applied to each part of the connecting member a main factor. For example, the shearing deformation is in proportion to the actual measurement Lo and thickness according to known formulas. The deformation by bending torsion is a function of the thickness (t), width of the convex part (4a), and height and lengths of the element (a, c, i), which are apparent and thus one can determine the value without much difficulty. Therefore, the geometrical pattern and a cross sectional shape most advantageous for satisfying the dynamic characteristics necessary for a design may be obtained.

The method for manufacturing a variable, rigid flexible bearing wall with use of connecting members 4 as mentioned above, will now be described. Indentations 3a are provided in the circumferential portions of a precast wall board 3 for use as a bearing element at a pitch necessary for a given design. The indentations 3a have, of course, the size and shape needed to enable the attachment of the connecting members 4 from the side. Toward the bottom of and indentations 3a, an anchor plate 5 is provided which has been made into a wall board 3 by welding of reinforcing members 3b.

On the other hand, a gusset plate 6 is welded at the position corresponding to the indentation 3a in structural steel post 1 and structural steel beam 2 which is included in the Rhamen construction. The Pca wall board 3 is hung in the construction formed by connecting members 4, 4 and is strongly secured by bolts 7 and nuts 8, on both surfaces of anchor plate 5 and gusset plate 6, which directs indentations 4a outwards. As a result thereof, clearance c, allowable in design between steel structural post 1, steel structural beam 2, and Pca wall board 3 is provided.

The bearing wall according to the invention is, as mentioned above, constructed such that the structural steel construction and the Pca wall board are structurally joined by means of connecting members 4 so as to allow clearance c between them. Therefore, a route is constructed, so that the horizontal force loaded thereto is first borne by the structural steel construction, and then the force is transmitted to the wall board 3 through the con-necting members 4 with deformation of the construction.

Accordingly, supposing that the shearing rigidity of structural steel construction is K.sub.12, the shearing rigidity of Pca wall board is K.sub.3, and the sum total of the shearing rigidity of the connecting members is .SIGMA.K.sub.4, the shearing rigidity Ko of the building can be calculated by the formula; Ko .apprxeq. K.sub.12 + .SIGMA. K.sub.4, disregarding the rigidity of the wall board. As previously noted, since the rigidity K.sub.4 of connecting member 4 can be designed separately from the bearable force, Ko can be varied freely by varying the design characteristics creating .SIGMA. K.sub.4, and thus the variable, rigid flexible bearing wall can be construct.

The toughness can also be varied freely. That is, since there is provided, relative to the Pca wall board, a clearance sufficient to allow the deformation of the structural steel construction within the range of design, and Pca wall board 3 is considered as completely rigid, the toughness desired can be obtained by designing the desired flexible deformation into the connecting member.

As for the method of obtaining the desired values for the bearable force, rigidity and toughness in connection with the idea according to the invention, there are some other methods, which will be described below, in addition to design of the measurement of the connecting member and design for a most suitable cross section.

FIG. 8(A) shows an embodiment, in which a structural steel construction and Pca wall board 3 are joined by two connecting boards 9, 9 having three indentations in rectangular shape.

FIG. 8(B) shows an embodiment, in which the structural steel construction and wall board are joined by means of two connecting members 10 having four rounded corner indentations, and FIG. 8(C) shows an embodiment, in which two connecting members 11, 11 having are reversed trapezoids in shape and are employed for joining. The actual measurement Lo of each connecting member can be adjusted in every value by the number of indentations, and a connecting member provided with various dynamic characteristics in addition to the effect produced by shape of the part can be designed, thus the purpose of a variable rigid bearing wall being realized freely.

In connection with a connecting member comprising the same variable rigid bearing wall, the possibility of variable rigidity has been sought on the basis of the actual measurement Lo for the connecting member (4), but for this reason there is a trend toward a lack of bearing force capabilities, depending on the purpose, in the Y direction. This disadvantage has been solved by employment of connecting member 12 shown in FIG. 10.

To describe connecting member 12 briefly, it shape is made merely by rotating the member shown in FIG. 10 90.degree.. A rectangular shaped convex part 12a is directed in the longitudinal direction, and surface portions 12c and 12d on the both sides thereof are provided with plural bores 12b for vertical bolts.

However, the connecting member 12 has shearing rigidity relative to the horizontal force in the X direction the same as that of those shown in FIG. 9, and has, on the other hand, an extremely strong bearing force capability and rigidity relative to the vertical force in the Y direction.

Further, its characteristics will be described in detail. The yield strength relative to the vertical load in the Y direction is determined by the cross sectional area [t x (2b.sub.1 + b.sub.2 + 2h)]. The yield strength and deformation relative to the horizontal force in the X direction are mainly caused by bending, shearing and torsion, which have as their principle factors the shape of the cross section, measurements b.sub.1, b.sub.2 and h for each part, and length 1 of the member. In conclusion, even connecting member 12, provides effective dynamic characteristics which can be designed, thus obtaining a most suitable gemetrical section along with the shape and measurement of part 12 in response to the dynamic characteristics.

The connecting member 12 mentioned just above is also used in the same manner as connecting member 4, as previously described, to construct a variable, rigid bearing wall.

That is, as shown in FIG. 11, part 3a is provided in the circumference of the wall board 3, and anchor plate 5 connects to wall board 3 in the bottom of the part 3a connecting member 12 is incorporated, directing part 12a outwards, along the surfaces of both sides of gusset plate 6 welded to the structural post 1 or structural beam 2 and anchor plate 5, and is strongly secured by bolts 7 and nuts 8.

It has previously been described in the description regarding connecting member 12 that the bearing force, rigidity and toughness are varied by varying the number of parts 12a, and width b.sub.2, height h, and thickness t of the same, and further the width b and length l of the member. The following methods are employed as steps for the accomplishment of this variance.

First, FIG. 14 shows an embodiment, in which a variable, rigid bearing wall is constructed by employing connecting member 13 provided with two rectangular shaped indentations 13a, while there is used only one indentation 12a in the embodiment shown in FIG. 11.

FIG. 15 shows an embodiment, in which a variable rigid bearing wall is constructed. Among the esential factors of part 3a and anchor plate 5 of the Pca wall board 3, which has been used in previous embodiments, are anchor plate 14 which projects to the circumference of Pca wall plate 3, and long plate-like gusset plate 15 which is welded to the side of the structural steel construction the post 1 and beam 2. Then the structural steel construction and Pca wall board are secured by bolts with the use of long connecting member 16 provided with a number of rectangular shaped areas 16a.

In this case, the shearing rigidity relative to the horizontal load becomes smaller, but the bearing force relative to the vertical load is as strong, and joining work is very easily carried out.

FIG. 16 shows an embodiment, in which a variable, rigid bearing wall is constructed with the use of connecting member 17 having a rectangular shaped part 17a inclined at a suitable angle .alpha. relative to the vertical direction. As seen from this embodiment, when angle of inclination .alpha. is established with the connecting member, there exists a main stress surface having a certain angle relative to the horizon by the effect of angle .alpha., while according to the embodiment in FIG. 11 the main stress surface is positioned in a horizontal relation to the vertical load, whereby. Thus, even if a member is provided with a geometrical section having the same shape, designing can be further freely extended, when considering a bearing wall, because the bearing force, rigidity, shearing rigidity, and the amount of deformation in connection with the bearing wall are varied depending on the size of angle .alpha..

Now, a connecting member, which is much different from that of ideas according to the aforesaid two systems and which is manufactured very simply and at a low cost, will be described. The object for using thus member in order to con-struct the variable, rigid bearing wall and the dynamic characteristics to be incorporated therein are, however, the same.

FIG. 17 shows the first embodiment thereof, in which a square or rectangular shaped steel plate is cut out in its nearly central portion in the longitudinal direction and in a rectangular shape so as to have a connecting member 18 shaped to be a gate stood on end. Holes 18a are formed for bolts.

The dynamic characteristic will now be described, supposing that the height of the connecting member 18 is a, the width is b, and the width of the cut out part is b.sub.1, the cuts depth is a.sub.1 and the thickness of plate is t.

Relative to the vertical load in the Y direction, the strength is determined by the cross sectional area (2 .times. b.sub.2 t) of rising portions 18c, 18d on both sides. Relative to the horizontal load in the X direction, secondary moment (2 .times. t .sup.. b.sub.2.sup.3 /12) for sections of the rising parts 18c, 18d will be the main factors. And, relative to the elastic deformation, elastic modulus E for the material and length a will be the main factors. Deformation by means of bending moment increases or decreases in proportion to a cubed, and the bearing force can be adjusted in accordance with varying the thickness t of plate.

As illustrated in FIGS. 19 and 20, a connecting mem-ber 18 is positioned opposite part 3a of Pca wall board 3 hung in the surface of the structural steel construction, and the end surfaces of rising parts 18c and 18d are butt welded on post 1 or beam 2. Bolt 7 and nut 8 are used to secure anchor plates 5, and thus a variable, rigid bearing wall can be constructed.

It is advantageous for cut out portion 18a to be, instead of a complete rectangular, in the form of a U-shape, provided with roundnesses at the corner portions, so as to prevent stress concentration.

FIG. 18 shows the second connecting member 19 developed on the basis of the same idea as above. This shape is made by cutting out the central portion of square or rectangular steel plate so as to form a hole similar to the outer shape of steel plate.

A variable, rigid bearing wall with use of a connecting member 19 is constructed in the manner illustrated in FIGS. 21 and 22, wherein gusset plate 6 is welded at the position opposite part 3a provided in the wall board 3, and holes 19a for bolts for two connecting members are used for securing by means of high tensile-strength bolt 7 and nut 8.

The dynamic characteristics of connecting member 19 are also similar to those described above and the deformation by bending moment will increase or decrease in proportion to (a) cubed. The bearing force relative to the vertical force can be adjusted varying the design of width b.sub.1 and thickness t of plate for the cut out portion 19b.

Finally, a connecting member 20 shown in FIG. 23 is an embodiment in which H-steel is used in a manner similar to that shown in FIG. 17. The connecting member shown in FIG. 24 is an embodiment, in which channel steel is used in a manner similar to the above.

Also, the connecting member 22 shown in FIG. 25 is an embodiment in which H-steel is used in a manner similar to that illustrated in FIG. 18. A connecting member 23 shown in FIG. 26 is an embodiment in which channel steel is used in a manner similar to the above. All of the aforesaid four embodiments show examples, in which the area of bearing force relative to the vertical load is increased by a flange of shape steel.

Claims

What is claimed is:

1. In a building structure having structural steel support members, and precast concrete bearing walls, said bearing walls having plural spaced indentations therein, the improvement comprising plural pairs of shaped steel connecting means, each having at least one bend symmetrical about a centerline between each pair positioned in said indentation and attached to said steel support members, and attaching means rigidly fixing said connecting means to reinforcing means contained in said precast walls.

2. The structure of claim 1 wherein said connecting means are steel plates in sinusoidal shape.

3. The structure of claim 1 wherein said symmetrical connecting means each contain a plurality of bends.

4. The building structure of claim 3 wherein each of said shaped steel pieces contains a plurality of angular bends.

5. The building structure of claim 4 wherein said angular bends are 90.degree. angles.

6. The building structure of claim 1 wherein said attaching means project between said connecting means along said centerline.