A completely new structura! system has been invented. This is steel-wood composite structure using light gauge steel sheet warping around standard wood members to achieve exceptfonal structura! performance chat is superior to that when either steei or wood used along. Just to name a few of a very long list, the merits of the novel system include higher strength and ductility, stronger yet simpler connections, better fire and erosion resistance, and higher quality and light weight. The present invention covers the who!e structura! system, which includes components, their connections, vertical gravity framing systems and lateral setsmic/wind systems, ft will change the way Iight-framed structure being tradttionaiiy designed and constructed, and has the potential to eventually reform the current market of iight-framed construction in the United States. The economical and social impact on building construction industry will be incredible.

By definition, "composite structure" combines different materials together to form a new structure. Since it fully utilises the potential of individual materials, the advantages of composite structures have been weil recognized in the engineering community during the past decades. However, past applications are mostly combining steei and concrete in various forms, and primarily used in commercial buildings and infrastructures. For example, concrete-filled steel tubes, composite floor decks etc.

In the meanwhile, both wood structure and light gauged steel structures have been in existence for very long time. As a matter of fact, they are the two primary Sight-framed structural: systems that are currently widely used in residential and low-rise commercial buildings across North America. However, the benefit of combined these two systems together have never been discovered and explored. For the first time in the history, the present invention combines these two systems in a systematical approach to create a brand new and better structura! system. The importance of present invention is comparable to "adding steei rebars into concrete", a simple yet historical invention that had reshaped the world we are living.

List of additional figures:

Fie.13: Circular composite pole of truncated-cone shape

(a) Solid core with truncated-cone shape. It could be made of regular wood,

engineering wood. For light duty usage, plastic or foam can also be used. The straight groove along the height at the perimeter is to allow metal jacket being bended into it for a smooth finishing surface of the final product. The hole at the middle is for electrical wires and cables going-through when needed, as light poles, for example.

(b) Segment of composite pole;

(c) Light-gauged cold-formed steel jacket.

Fig.14: Circular composite rod

(a) Solid wood rod core with a straight groove along the height at the perimeter to allow metal jacket being bended into it for a smooth finishing surface of the final product.

(b) Circular composite rod;

(c) Light-gauged cold-formed steel jacket;

(d) Magnified view of metal jacket detail.

Fig.15: Example applications of metal-jacket composite pole. The light-weighted products are intended to replace many heavy steel or concrete infrastructures, for example:

(a) Flag poles;

(b) Street light poles;

(c) Traffic signal lights and signs supporting structures.

Fig.16: Example applications of metal-jacket composite rod. This product is intended to replace steel pipe in many light weight supporting structures, for example:

(a) Traffic sign poles;

(b) Poles for wire mesh fence.

Fig. 17: Composite joist used as floor framing supported on a typical stud wall

Fig.18: Typical triangular roof truss made of composite s studs:

(a) Wood cores;

(b) Composite studs, connected together with connection steel plates and screws, to form a typical roof truss;

(c) Metal jackets; Fig.19: Magnified views of tvpical connection of the truss shown in Figure 18: (note that screws are shown, but connection plates not shown for clarity)

(a) Connection at support;

(b) Connection at top;

(c) Intermediate connection at bottom code.

Fig.20: Segment of open web truss made of composite s studs

Fig,21: Composite post with composite beams at bottom and top

Fig.22: Composite sheeting made of lamination of plywood and metal sheet. The plywood and the metal sheet is connection through pre-punched teeth, and it is of typical plywood dimension, i.e. 4 ft x 8 ft. There are additional pre-drilled circular holes on the metal sheet. There holes follow certain pattern to allow convenient nailing at field without additional drilling. This type of sheathing is intend to be used in combination with composite stud to form a new type of shear wall systems, as shown in Figures 10 and 11. The performance is expected much better than traditional shear walls, either wood or metal ones, as illustrated in Figure 12.

Fig.23: Magnified bottom views of composite sheathing shown Figure 18: Connection at top;

(a) Typical plywood;

(b) A piece of composite sheathing with wood and metal laminations;

(c) Metal sheet with pre-punched teeth and pre-drilled holes.

Fig.24: Magnified top views of composite sheathing shown Figure 18: Connection at top;

(a) Typical plywood;

(b) A piece of composite sheathing with wood and metal laminations;

(c) Metal sheet with pre-punched teeth and pre-drilled holes.