Lateral force resisting system

Abstract

A lateral force resisting system according to the present disclosure includes a metal lateral force resisting panel and holdowns. A foundation bolt placement template may be used to locate and support the foundation bolts during fabrication of the foundation and to further secure the frame foundation interface. The metal lateral force resisting panel may be formed from a single piece of material and may include a plurality of ductility apertures forming lateral force resisting elements to enable the panel to flex without catastrophic failure. In a hybrid configuration, a wooden structural frame may be combined with the metal structural panel. The structural panel may be subdivided into multiple panes using ductility apertures to tailor the response of the panel to the lateral force load. The holdowns secure the rigid structural panel to the foundation bolts and may be either a folded strap and pin configuration or self-tightening.

Description

RELATED APPLICATIONS [0001] This application is a divisional application of copending U.S. patent application Ser. No. 11 / 224,742 filed Sep. 9, 2005 which is a continuation-in-part of U.S. patent application Ser. No. 09 / 884,709 filed Jun. 19, 2001, which is a continuation-in-part of U.S. patent application Ser. No. 09 / 697,030 filed Oct. 25, 2000, which is a continuation of U.S. patent application Ser. No. 09 / 060,930 filed Apr. 14, 1998, now U.S. Pat. No. 6,158,184, which claims the priority of U.S. provisional patent application Ser. No. 60 / 043,835 filed Apr. 14, 1997.BACKGROUND [0002] 1. Field of the Inventions [0003] The inventions relate generally to the field of building construction and in particular to structural framing elements for building construction. [0004] 2. Description of Related Art [0005] Buildings are subjected to many forces. Among the most significant are gravity, wind, and seismic forces. Gravity is a vertically acting force, wind and seismic forces are primaril...

AI Technical Summary

Benefits of technology

"The patent describes a lateral force resisting system for building frames that can be used in both wood and metal frame buildings. The system includes metal or hybrid panels made of steel or a combination of steel and wood, holdowns to secure the panels to the frame, and a foundation bolt placement template. The panels have ductility elements to resist catastrophic failure and can be tailored to the lateral force load. The system can be used in a hybrid configuration with a wooden frame and the metal panel. The panels have lateral resisting elements formed by ductility apertures and can be secured to foundation bolts using folded straps and pins or self-tightening holdouts. The system provides a unified approach to resist lateral forces and protect the frame from failure."

Problems solved by technology

The structural contribution of a drywall panel is limited because of the relatively delicate composition of the drywall.

Review of damage following the Northridge earthquake, revealed that many plywood sheathed shearwalls failed under the seismic forces.

The nailing of the sheathing in the field during construction leads to many failures.

Nail heads penetrate the skin of the sheathing during nailing which weakens the sheathing and allows the nails to be pulled through the sheathing under load conditions as well as inducing failures in the integrity of the sheathing.

Current field fabrication techniques are not sufficiently accurate to consistently meet the design specifications.

The interface between the shearwall and the foundation may also be area of weakness.

Quite often the bolts that are supposed to secure the walls and shear panels are placed several inches away from where they are required for optimum load transfer and ease of wall construction due to inaccurate measuring and carelessness during field installation of the bolts.

The resulting attachment of the wall to the foundation is a potential point of failure.

Another common fabrication error is oversize holes in the mudsill.

Many different causes result in holes in the mudsill which don't line up with the bolts placed in the foundation or in the stem wall.

This requires extra holes, or oversize or elongated holes be created in the mudsill which may weaken the frame-foundation interface.

The attachment hardware that may be used to connect a shearwall to the foundation may be another point of weakness.

If a field-fabricated shearwall were ever built in exact compliance with the design, the attachment hardware would likely fail before the shearwall.

In other cases, the method of attaching the attachment hardware to the studs induces cracking of the studs.

Another problem exposed by the Northridge earthquake is the illusion that stiffer is better where lateral force resistance is desired.

The result in an earthquake was that the very stiff I-beams experienced catastrophic failure.

As a result, most conventional manufactured shear panels experience catastrophic failure when developing their maximum shear resistance.

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