Composite energy absorbing structure

Abstract

A composite structure including a shear wall panel having at least one horizontally-disposed structural member at least partially embedded in a floor slab such that horizontal forces exerted on the floor slab are transferred to the shear wall panel through the structural member.

Description

FIELD OF THE INVENTION

The present invention relates to an energy absorbing structure which is constructed to transfer horizontal forces from floor slabs to shear wall panels to permit buildings to withstand earthquakes and other forces exerted on them.

BACKGROUND OF THE INVENTION

Earthquakes exert lateral and vertical forces on a building, and fabricating a structure that will withstand these random, often sudden forces is a complex task. When designing an earthquake-resistant building, engineers can choose various structural components, such as shear walls, braced frames, moment resisting frames, diaphragms and horizontal trusses. These building elements impart earthquake resistant structures with the ability to resist and sometimes to absorb and dissipate seismically induced motion through a combination of means, including damping means which absorbs energy and decreases the amplitude of oscillations of a vibrating structure and inelastic deformation means which can withstand considerable inelastic deformation. The structural elements can be used alone or in combination to achieve the necessary strength and energy absorption and dissipation.

Shear walls are an example of a structural element used in earthquake resistance structures. A shear wall is a vertical element in a building lateral load resisting system that transfers horizontal forces vertically downward from a diaphragm above to a diaphragm or a foundation below. Thus, horizontal wind or seismic forces are collected at floor or roof diaphragm levels and transferred to the building foundation by the strength and rigidity of the shear walls. In a lateral load resisting system, concrete floor slabs often act as diaphragms, and thus the connection between the floor slabs and the shear wall panels is critical for effective transference of lateral forces. In this regard, the stronger the connection between the shear wall panels and the floor slabs, the more effective the entire lateral load resisting system will be in transferring lateral loads to the foundation.

Accordingly, there is a need for a means to provide a strong connection between floor slabs and shear wall panels in a building lateral load resisting system to improve the effectiveness of the system in transferring lateral loads to the building foundation.

SUMMARY OF THE INVENTION

According to the present invention, a shear wall panel partially embedded in a floor slab transfers horizontal forces from the floor slab to the shear wall or from one floor slab to an adjacent floor slab. Specifically, a composite energy absorbing structure according to an exemplary embodiment of the present invention includes a shear wall panel having at least one horizontally-disposed structural member at least partially embedded in a floor slab such that horizontal forces exerted on the floor slab are transferred to the shear wall panel through the structural member.

In at least one embodiment, the structural member includes two or more bars each having an angle shape in cross section and each having a vertical leg and a horizontal leg.

The invention also encompasses a method of forming a composite structure in a building, including forming a shear wall panel having a structural member, and at least partially embedding the structural member in a floor slab, such that horizontal forces exerted on the floor slab are transferred to the shear wall panel through the structural member.

These and other features of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of this invention

BRIEF DESCRIPTION OF THE DRAWINGS

Various exemplary embodiments of this invention will be described in detail, with reference to the following figures, wherein:

FIG. 1 illustrates a shear wall according to an exemplary embodiment of the present invention;

FIG. 2 illustrates a shear wall according to another exemplary embodiment of the present invention;

FIG. 3 is a cross-sectional view along the line A-A shown in FIG. 1; and

FIG. 4 is a perspective view showing the shear wall of FIG. 1 including a structural member imbedded in a floor slab.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The various exemplary embodiments of the present invention are directed to a shear wall that imparts buildings with the ability to withstand forces caused by, for example, earthquakes. The shear wall includes multiple shear wall panels, each including, as a component, a structural member, that transfers horizontal forces exerted on floor slabs, in which the structural member is at least partially embedded, to the shear wall panel. It should be appreciated that the various concepts of the present invention are not necessarily limited to earthquake resistant structures, but are also applicable to structures that are designed to withstand forces generated by any other factor, such as, for example, explosions or high winds. It should also be appreciated that the present invention is not limited to the particular shear wall structures expressly illustrated herein and that other shear wall structures may be used.

FIG. 1 shows a shear wall panel, generally designated by reference number 10, according to an exemplary embodiment of the present invention. The shear wall panel 10 may be one of many such panels that make up one shear wall of a building. The shear wall panel 10 is composed of a generally rectangular shaped frame including two vertically disposed frame members 12 and two horizontally disposed structural members 14. An opening 16 is defined by the frame members 12 and structural members 14 within the shear wall panel 10. The frame members 12 and structural members 14 may be attached to each other by any suitable means, such as, for example, pin joints, welding, bolts or connector elements 18.

The shear wall panel also includes shear transfer means which can take any useful form. FIG. 1 shows the shear transfer means as diagonal braces 20. Another type of shear transfer means may include a shear panel or a suitable energy absorber such as shown in FIG. 2 and described in co-pending U.S. patent application Ser. No. 10/941,159, incorporated herein by reference. Specifically, referring to FIG. 2, the energy absorber, generally designated by reference number 21, includes a ductile member 22 and four braces 24. The braces 24 support the ductile member 22 at substantially the center of the opening 16. The ductile member 22 is formed of a ductile material, such as, for example, steel or aluminum. One of the ends of the braces 24 are connected to the ductile member 22 by any suitable fastening elements, such as, for example, adjustable nuts 26. The opposite ends of the braces 24 are attached to respective corners of the connector elements 18 by, for example, pin joints, welding or bolts. The number of braces 24 is not limited to four and any number of braces 24 can be used in the various exemplary embodiments of the invention. In the present embodiment of the invention, the braces 24 are tension rods, but can also be any other suitably rigid structural supports for the ductile element 22. Further, the ductile member 22 need not be ring-shaped, as shown in FIG. 2, but could have other shapes as would be understood by workers skilled in the art.

Structural members 14 can take any useful form, for example angles or I-beams. As best seen in FIG. 3, which is a cross-sectional view along the line A-A in FIG. 1, the structural members 14 may each include two metal bars, generally designated by reference numbers 26, 28. Such structural members are disclosed in U.S. Pat. No. 4,592,184, incorporated herein by reference. Each of the bars 26, 28 have an angle shape and include a vertical leg 30 and a horizontal leg 32. The horizontal leg 32 of the bar 26 extends in the opposite direction from that in which the horizontal leg 32 of the bar 28 extends. The height of the vertical legs 30 of the bars 26, 28 are preferably the same, although in other embodiments the heights may be different. The vertical legs 30 of the two bars 26, 28 are spaced apart by the width of the connector elements 18. Concrete engaging means 34 such as, for example, protrusions or slots are preferably formed at spaced intervals along the length of the vertical legs 30. It should be appreciated that the bars 26, 28 may have any other suitable shape.

As best shown in FIG. 4, a shear wall panel 10 is incorporated into a building structure by forming the concrete floor slab 36 in intimate contact with shear wall panel 10. In this regard, concrete may be poured such that the structural member 14 is at least partially, but preferably completely, embedded in the floor slab 36. The floor slab 36 may form a component of a flooring system, such as the flooring system disclosed in U.S. Pat. No. 4,592,184. The shear wall panel 10 may also extend upwards into an upper floor, such that the upper structural member 14 may also be embedded in a floor slab 36 of an upper flooring system. Many such shear wall panels are embedded in the floor slabs of a building to form the entire building structure.

By placing the floor slabs 36 in intimate contact with the structural members 14, any horizontal forces exerted on the floor slabs 36 will be transferred to the shear wall 10 through the structural members 14 and/or from one floor slab to a neighboring floor slab. The deformed structural members 14 enable the floor slabs 36 to more effectively act as diaphragms in transferring energy to the shear wall 10 or to a neighboring floor slab 36.

While this invention has been described in conjunction with the exemplary embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the exemplary embodiments of the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention.

Claims

1. A composite energy absorbing structure comprising:

a shear wall panel having at least one horizontally-disposed structural member partially embedded in a floor slab such that horizontal forces exerted on the floor slab are transferred to the shear wall panel through the structural member.

2. The composite energy absorbing structure of claim 1, wherein the structural member comprises two or more bars each having an angle shape in cross section and each having a vertical leg and a horizontal leg.

3. The composite energy absorbing structure of claim 2, wherein the structural member includes a concrete engaging element formed in the structural member to enhance the connection between the floor slab and the shear wall panel.

4. The composite energy absorbing structure of claim 2, wherein the two or more bars are made of metal.

5. The composite energy absorbing structure of claim 1, wherein the shear wall further comprises:

a frame having an opening; and

an energy absorber disposed in the opening.

6. The composite energy absorbing structure of claim 5, wherein the energy absorber comprises:

one or more ductile members; and

two or more bracing members that support the one or more ductile members within the opening, wherein, when a force is applied to the energy absorber, the one or more ductile members deform to absorb energy.

7. The composite energy absorbing structure of claim 5, wherein the frame further comprises:

at least one vertically-disposed frame member; and

connector elements that connect the at least one frame member to the at least one structural member.

8. A method of forming a composite structure in a building including one or more floor slabs, comprising:

forming a shear wall panel having a structural member; and

at least partially embedding the structural member in a floor slab, such that horizontal forces exerted on the floor slab are transferred to the shear wall panel through the structural member.

9. The method of claim 8, wherein the shear wall panel has at least two structural members and the method further includes the step of embedding each of the structural members in a floor slab.

10. The method of claim 8, wherein the step of forming a shear wall panel comprises:

connecting a vertically-disposed frame member to the structural member to form a frame having an opening; and

disposing an energy absorber in the opening.

11. The method of claim 10, wherein the step of disposing an energy absorber in the opening comprises:

connecting respective first ends of two or more bracing members to a ductile member;

disposing the ductile member within the opening; and

connecting respective second ends of the two or more bracing members to the frame.