The main purpose is to provide an economical solution for agricultural buildings and is intended for the construction of barrel vaults or round-type buildings that can be covered by fabric, steel cladding, or plywood and shingles.
These frames are assembled by interconnecting segments, which are comprised of curved or linear lower and upper chords joined together by a vertical web panel. Chords are made from wood, usually of the spruce-pine-fir type, and the web panel of plywood or oriented strand board (OSB).
Adjacent segments are interconnected using steel straps bolted to the chords and plywood web connectors bolted at both sides of each connection.
The present invention pertains to a wood arch frame system, usually curved, mainly used in economical agricultural constructions in which the main component are wooden arch frames which have a cross-section similar to wood joists presently available in the building market. The main component of these frames is the arch segments, which can then be interconnected to form the arch frames.
Wooden joists are increasingly used in a large number of building applications. They comprise upper and lower wood chords with a web system composed of a diverse type of materials.
One such wood joist may be found in U.S. Pat. No. 5,867,963 issued Feb. 9, 1999 to Hershey. Another joist may be found described in Canadian patent application 2,008,043 published Jul. 18, 1991 issued to Lemyre.
The present invention, on the other hand, presents a curved wood structure that can be economically used for buildings with diverse free span lengths, and amenable to a diversity of covers like fabric, metal cladding or plywood and shingles.
In U.S. Pat. No. 4,336,678 issued Jun. 29, 1982, wooden joists are described with a web member formed of sheet material such as plywood. In the present invention, the wooden structure is generalized to linear or curved arch shapes, and specific solutions are given for the interconnection between the arch segments that form part of the wood frame.
In Canadian patent No. 1,059,872 issued Aug. 7, 1979 to Philip Sprung, a building system is described with steel members covered by fabric. In the case of the present invention the improved system that is intended has a curved arch frame structure made of timber which is more economical and which makes it easier to implement future building modifications or expansions.
It is an object of the present invention to provide a novel wooden arch frame system consisting in manufacturing curved arch segments, which can be interconnected to form a wood frame structure. A plurality of these wood frames is spaced over a number of bays to create a system that will produce an economical barrel vault type building. This structure is then amenable to economical covers like fabric, but can be covered by sheet metal or plywood and shingles as well.
The same frames can be used in halves that can be interconnected to assemble a circular or round building, which can be an economical solution required in other agricultural uses.
The present invention relates to a structural wooden arch segment which comprises: a) an elongated lower chord; b) an elongated upper curved chord generally but not necessarily parallel to the lower chord, and c) a web joining the chords usually of plywood or OSB material.
The arch segments connect to produce the wood arch frame in the following manner: a) the two chords connect by means of a steel strap bolted to both sides of the connection, and b) the web connects to the abutting web by using a wooden bolted web connector of the same material as the web.
The chords for each arch segment are made of kiln-dry wood, preferably one selected from the group that includes fir-spruce-pine.
Other aspects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that this detailed description, while indicating preferred embodiments of the invention, is given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.
FIG. 1 is an elevational view of a wooden arch segment made in accordance with the present invention.
FIG. 2 is a cross-sectional view taken along view line A-A.
FIG. 3 is a cross-sectional view taken along view line B-B.
FIG. 4 is a cross-sectional view taken along view line C-C.
FIG. 5 is a plan view of a building in the shape of a barrel vault composed of the wood arch frames built in accordance with this invention.
FIG. 6 is a cross section of this building along line D-D showing a typical wood arch frame composed of arch segments.
FIG. 7 is a plan view of a round building built with the wood arch frames reported in this invention.
FIG. 8 is a cross-sectional view of the round building built with the arch frames taken along view line F-F.
FIG. 9 is an enlarged elevational view of the base web panel, which is part of the web of the arch segment closest to the support of the wood frame.
FIG. 10 is an enlarged elevational view of two arch segments connected with steel straps and wooden web connectors.
Referring to FIG. 1, representing an arch segment, the main constituent of the wood arch frame system, it comprises a curved upper chord 10, an elongated lower chord 11 which can be linear or curved, both chords being spaced apart and usually parallel.
Between the upper and lower chords is provided a plywood or OSB web panel 12, adhesively joined to chords 10 and 11.
At the ends of top chord 10 can be seen the bolts required for the connection with an abutting arch segment, and indicated as 16. Similarly, at the ends of bottom chord 11, the bolts 17 shown are for the connection to another arch segment. The bolts 18 shown in the stiffeners 15 are required for the connection of the webs of abutting arch segments. We also observe web splicers 14 glued at both sides of the web 12, at lines of discontinuity 13.
In FIG. 2, representing cross section A-A taken in FIG. 1, the web 12 is adhesively joined into grooves shown with the numeral 12a created in the chords 10 and 11, or alternatively scarf joints can be used to assure more positive web-chord connection for handling purposes. Glue is used to secure this joint.
In FIG. 3, representing section B-B taken in FIG. 1, we observe the plywood or OSB web splicers 14 glued at both sides of the web panel 12, at lines of discontinuity. The glue used in securing the splicers as well as that used in the joints between web panels and chords 10 and 11, preferably has a base of resin resorcinol, such as phenol resorcinol resin, or one having a base of urethane or similar products approved for structural wood products. In addition, this FIG. 3 also indicates alternative possibilities of web arrangement indicated by 12b, glued to the side of the chords.
FIG. 4, shows section C-C taken in FIG. 1, at the ends of arch segments, representing the wood stiffeners 15, which are glued to web panel 12, and screwed to chords 10 and 11 with screws 16.
FIG. 5 represents a typical plan of a building, built with the wood arch frame system, in which the frames 20 are spaced apart by a bay length shown as 21, and the transversal elements called purlins are shown as 22. The purlin braces 23 are used to shorten the unsupported length of the purlins and arch frame chords. The tensor elements 24 are introduced to give lateral stiffness to the system and also assure that purlins can be used to brace the arch chords.
FIG. 6 is a representation of cross section D-D taken in FIG. 5 above, representing a typical wood arch frame, in which in this case there is a central arch segment 30, a support arch segment 31 and another support arch segment 32. At specific locations inside the arch segments the cross section indicates wood stiffeners 33, to which purlins, shown with the numeral 22, are connected by screws during the site installation of the full wood arch frame system. The special support segments 31 and 32 have a base web panel indicated as item 35.
FIG. 7 represents a round construction built with the arch frame system. The frames indicated as 20, are spaced at angles shown with numeral 21A and are connected at the center to a hub indicated with the numeral 25. Same as in the barrel vault, the chords of the wood arch segments are laterally braced by purlins indicated by numeral 22, and the system attains its spatial rigidity through the use of tensors numbered 24. The purlin braces 23 contribute to shorten the free buckling length of both purlins 22 and frames 20.
FIG. 8 shows a cross section F-F of the round building of FIG. 7 showing mainly the central hub 25 around which are connected the halves of wood arch frames constructed as per the present invention.
FIG. 9 represents the base web panel 35, built with the same wood as the chords, glued and fastened by lag bolts 42 to the chords 10 and 11. This panel has a hole 43 through which a steel pin is passed in order to connect it to steel connector 44 which transmits the external loads exerted on the wood arch frame to the foundation indicated with the numeral 45.
FIG. 10 is a larger representation of the interconnection between arch segments, showing steel straps 51, bolted at both sides of the connection, to chords 10 and 11, with bolts 52, and the wood web connector plate 53 connecting the webs of the arch segments at both sides of this connection with bolts indicated as 54.
Although the invention has been described above with respect to one specific form, it will be evident to a person skilled in the art that it may be modified and refined in various ways. It is therefore wished to have it understood that the present invention should not be limited in scope, except by the terms of the claims.