US2985987A - Roof structure - Google Patents

Description

Gl R. KlEWlTT ROOF STRUCTURE May 30, 1961 May 30, 1961 G. R. KlEwlTT 2,985,987

ROOF STRUCTURE Filed Nov. 9, 1955 5 Sheets-Sheet 2 GQ R. KlEWlTT ROOF STRUCTURE' May 30, 1961 Filed Nov. 9, 1955 United States Patent() noon STRUCTURE Gustel R. Kiewitt, Ladue, Mo. (331 Thornton Ave., Webster Groves 19, Mo.)

Filed Nov. 9, 1955, Ser. No. 545,916 1 Claim. (Cl. 50--61) This invention relates to-roof structures, and with regardto certain more speciic'features, to skew-arch roof structure of the lamellar-latticed type shown in U.'S. Patents 1,483,037, 1,659,471 and 1,976,188.

Among the several objects of the invention may be noted the provision of skew-arch roof structures of the type shown in said patents which, without loss of essential strength, eliminate the lateral load distribution beams heretofore used for transmitting the stresses of the as- `sembled structure through buttresses to its footings; the provision of a roof structure of the class described which eliminates assembly difficulties encountered in the use of such beams and reduces undesirable stresses heretofore encountered in making attachments with the same; and the provision of such a structure which provides for larger unobstructed access openings from the sides of buildings employing the structure. Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the constructions hereinafter described, the scope of the invention being indicated in the following claim.

IIn Ythe' accompanying drawings, in which several of various possible embodiments of the invention are illustrated,

Y Fig'. 1 is a diagrammatic plan view of a roof structure embodying the invention;

` Fig. 2 is a diagrammatic end elevation of the structure shown in Fig. l;

Fig. 3v is an enlarged yfragmentary plan view of portions of Fig. l;

Figs 4 and 5 are views similar to Fig. 3 but showing alternative forms of the invention;

Fig. 6 is a typical cross-sectional detail taken on lines 6--6 of Figs. 3, 4 and 5; and,

- Fig. 7 is a top plan view of Fig. 6.

`Corresponding' reference characters indicate corresponding parts throughout the several views of the drawings.

`In the above-mentioned patents are shown roof constructions Vgenerally comprising angularly related steel or wood yelements of equalv lengths extending in one general. direction, eachl of which engages at its ends with approximately. central points of equal-length elements which extend in another general direction. The connected elements that extend in one general direction form skew arches in that direction and those that are connected and extend in the other direction form intersecting'skew arches extending in said other direction. Each of the arches of each skew set is brought to convergence with a corresponding arch or part thereof of the other skew set.

The practice heretofore has been to anchor to a distribution beam all of the above-mentioned skew arches at their points of convergence. This distribution beam was supported `up'on whatever load-carrying Systems were used, which systems in turn were carried upon suitable individual or spot soil pressure footings or upon continuous footings located sidewse of the structure, depending upon soil conditions, ln cases requiring it, the load- 'Patented May 30,1961

carrying systems, by transverse purlins, were prevented from spreading in response to horizontal thrusts.

Several disadvantages accrued to such prior constructions. First, the sides of the buildings roofed by such structures had an unduly large number of obstructions permitting only small side access openings to the building, unless the distribution beam was elevated; second, the distribution beam was unduly heavy and expensive to construct, particularly in view of the accuracy with which it was required to be made (generally of concrete); and, third, unless very great care was exercised in establishing the accuracy of the distribution beam, a large number of the points of convergence of said skew arches would not match it. The result was that when corresponding bolts at the connections thereto were drawn up tightly, the metal thrust pads in the beam might be pulled out, or, barring this, excessive stresses set up in the relatively stijf marginal portions of the skew arches of the latticed structures. i

By means of the present modified skew-archV structure, the distribution beam is entirely eliminated, along with its weight and cost, the sides of the building carrying the roof structure even without supporting columns may be provided with larger and more convenient unobstructed access openings, assembly with the supporting footings is facilitated, and, in view of the greater marginal liexibility of the resulting structure, fewer undesirable stresses ,are produced when the draw bolts are pulled up which anchor the structure to its supports.v v Referring now more particularly to Figs. 1-3, 6 and 7 of the drawings, there are shown at numerals 1twoA rows of soil pressure footings of concrete, located at or belo'w the grade G. These are of the so-called'spot-type, each being-separated from the other, but it is to be understood;

that the footings in each row, as is common practice, may be joined to form a continuous footing on each side of the structure, where required by `soil conditions. The footings carry buttresses 5.

The oppositely located footings may be joined by prestressed cables 3 which run through the bases of buttresses 5 and transverse protective jackets of concrete 7. On the buttresses 5 are bolted and grouted steel supports 9, providing pin joints 11 for junction blocks 13 of certain right-hand and left-hand skew-arch assemblies RS and LS forming a network as shown in the drawing. It will be understood that the right-hand and left-hand designations Iare arbitrary for descriptive purposes.

In general, each of the skew-arch assemblies RS andl LS is composed of wood, steel, or concrete (in the present case steel) elements 15 and 17 of equal lengths, the elements 15 of the right-hand arch assembly RS extending in one direction and the elements 17 of the left-hand arch assembly LS in the other direction. Each element 15 extending in the right-hand directionA engages at itsl ends with approximately central points of elements 17 extending in the left-hand direction, producing what isr known in the art as a lamellar-latticed arrangement. The term assemblies applied to the arches `RS and LS is intended to include partial arch assemblies such as appear at the ends of the building. Longitudinal pur- A elements 15 and 17 at points otherthan the joints be-' tween them. The assembly of skew arches RSjand LS and the parallel members 19 may be referred to as an arched network.

Heretofore, all of the complete right-hand and lefthand skew-arch assemblies RS and LS were made 0f equal lengths, by employing equal lengths throughout of the elements 15 and 17. This is suggested by the dotted triangles T at the upper left of Fig. 1. Thus there were required a number of junction blocks such as 13 equal in number `to the number of skew arches employed. To support these junction blocks it was the practice to employ adistribution beam at the location indicated by arrowB. This beam was carried Von the buttresses 5 and was `provided with the appropriate number of supports such as 9. This beam is not to be confused with any continuous equivalent of the footings 1.

I have found that the distribution beam, heretofore considered to be advantageous, in fact is disadvantageous from'the viewpoint of cost, weight complications in assembly and convenience of access to the building. The excessive cost arose from the necessity for the accuracy with which .the distribution beam was required to be constructed, usually of concrete. Inaccuracies resulted in inability to match conveniently the junction blocks 13 to the supports 9. Consequently, when the bolts 23 between the supports 9 and the buttresses 5 of the unmatched junction blocks 13 were attempted to be drawn up, one of two things occurred; either the bolts were pulled out of the distribution beam or, if this did not occur, excessive stresses were set up in the relatively stit margins of the roof structure. Moreover, as indicated in Fig. 2, maximum entrance height to the side of the building was limited to a distance such as h.

My improvement consists in reconstruction of the roof margins so as to eliminate the formerly used distribution beam and every other one or so of the junction blocks, as well as the adjacent parts which they join. For example, Fig. l shows that in the right-hand skew arches RS, every other one has an extra long element 15-L. The elements 17 of the left-hand arches LS, which join with elements 15-L, -are of standard length, but the elements 17-S at the other ends of arches LS are extra short. 'I'his eliminates the former triangular structural elements such as indicated by the dotted lines T of Fig. 1.

As will be seen from Figs. 2 and 3, the available height of the entrance opening has been increased from h to H, and its width has been increased from the pitch distance W between adjacent parallel skew arches to 2W. Moreover, the distribution beam has been omitted, not only withlthe disadvantages of its cost, but with the improvement that the assembly is more easily accomplished without so easily pulling out supports such as 9. This is for the reason that the margins of the structure are more flexible without the additional binding due to supports 9 that would be used at the ends ofthe dottedline triangles shown in Fig. 1. Also, yany stresses induced in the now more exible margins of the structure are reduced when all anchoring bolts are drawn up.

11n Fig. 4 is shown an alternative form of the invention, wherein only every third one of the junction blocks 13 and supports 9 are retained, thus eliminating twothirds of them, as indicated by the two dotted triangles T. The same advantages accrue to this construction, with the-additional one that the width of the entrance opening is increased to 3W, that is, three times the pitch distance W.

In Fig. is shown another alternative similar to that shown in Fig. 4, wherein the height of the entrance opening is increased more while retaining the width at 3W. This is accomplished by removing from between the elements 15-L and 17 the purlins 19, the short elements '17-S and one-half of the elements 15, thus leaving the extra space shown in Fig. 5 for increase in entrance height.

Between the lowermost stiiening elements 19 and 21 in all forms of the invention are inserted stitfening braces 25.

In view of the above, it will be seen that the roof structure of the invention comprises angularly related sets of skew arches LS and RS extending in two different general directions. 'I'he skew arches of each set have the same pitch distance W between them. Purlin members 19 cross-connect the skew arches in both sets, forming therewith an arched network such as shown, for example, in Fig. 1. A group less than all of the skew arches in each set extends beyond the arched network. In the case of the forms of the invention shown in Figs. 4 and 5, the distances between the members of each group is equal to at least three pitch distances W, which is to say, 3W. Junction blocks or means are shown at 13, which join the extending ends of the respective members of the groups of extending arches. These junction means form downward apexes of inverted supporting structural triangles, the sides of which are constituted by the extending arches. The apexes formed by the junction means are spaced apart a distance which is a multiple of the pitch distance W, and in Figs. 4 and 5 the multiple is three. The buttresses 5 are of course xed with respect to the footings 1. The invention makes possible more readily to draw together the junction means 13 and the buttresses 5 by means of the fastening members 23. It also alords wide lateral spaces below the arched network to afford lateral openings of substantial lwidths. These advantages are particularly evident in connection with the form of the invention shown in Figs. 4 and 5.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall lbe interpreted as illustrative and not in a limiting sense.

I claim:

A roof structure comprising angularly related sets of skew` arches, the skew arches of one set having a certain pitch distance between them and extending in one general direction, and the skew arches of the other set having the same pitch distance between them and extending crosswise in another general direction, parallel purlin members connecting the skew arches of both sets where they cross, said purlin members and the skew arches 'forming an arched network, a group less than all of said skew arches in each set extending beyond said arched network and having distances between the members of the group equal to at least three of said pitch distances, junction means joining the extending ends of respective members A of the groups adapted to form downward apexes ofinverted supporting structural triangles, said apexes being also spaced at said distances equal to at least three of said pitch distances, substantially xed buttresses adapted to support the respective junction means, fastening means adapted to fasten said junction means to the buttresses, whereby said buttresses and said junction means can conveniently be drawn together by said fastening means and whereby 4wide lateral spaces .are afforded below said arched network to afford accessopenings of substantial widths.

References Cited in the le of this patent UNITED STATES PATENTS 1,976,188 Nozawa oct. 9, 1934 FOREIGN PATENTS 146,466 Switzerland July 1, 1931

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