US2290195A - Roof and floor construction - Google Patents

Description

July 21, 1942.

A. M MlLLAN 2,290,195 ROOF AND FLOOR CONSTRUCTION Filed April 4, 1941 6 Sheets-Sheet l I .54 2 .53 J4 A g I I 27 2/ 22 y- ,1 A. M Ml LLAN 2,290,195

ROOF AND FLOOR CONSTRUCTION Filed April 4, 1941 6 Sheets-Sheet 2 wag.

July 21, 1942.

A. M MILLAN 2,290,195

RObF AND FLOOR CONSTRUCTION Filed April 4, 1941 6 Sheets-Sheet 3 7 July 21, 1942. A. M cMlLLAN 2,290,195

ROOF AND FLOOR CONSTRUCTION Filed April 4, 1941 6 Sheets-Sheet 4 July 21, 1942. A. MaCMILLAN I 2,290,195

ROOF AND FLOOR CONSTRUCTION Fild April 4, 1941 6 Sheets-Sheet s Patented July 21, 1942 UNHTED STATES FATENT QFFICE 15 Claims.

The object of the present invention is to provide a supporting structure for either roofs or floors, which effects a saving of material and is rendered rigid by reason Of th arrangement of the component parts, thereby eliminating the necessity for the bracing ordinarily provided in structures of the conventional type.

As applied to a roof construction, th methods characterizing the present invention permit a portion of the roof structure to be suspended in such a way as to provide for the admission of daylight and its more even distribution, without obstructing the floor, by the employment of additional columns or other structural elements beneath the suspended portion of the roof.

In the preferred embodiment of my invention, these depressed portions of the suspended roof structure are held in tension in such a way to reduce the length of the girders employed, and at the same time make provision for the admission of light at an angle which will more evenly illuminate the interior of the building.

The principles of construction hereinafter to be described lend themselves to numerous Variations in detail to meet special conditions, but in all cases the structural principles involved are those which afford a maximum of strength, rigidity, and mutual reinforcement throughout the structure by the employment of a minimum weight of structural material.

The principles of the present invention, as applied to floor construction, provide for adequate strength and rigidity, without the employment of braces or the like which extend below the ceiling level, so that the space beneath the floors will remain unobstructed by braces, trusses or the like, and by the utilization of principles of construction which more evenly and uniformly distribute the support throughout all portions of the floor structure, the stresses occasioned by an uneven loading of the floor will be distributed and resisted by structural elements which mutually reinforce one another and serve to stiffen the structure throughout.

Further objects and details will appear from a description of the invention in conjunction with the accompanying drawings, wherein Figure 1 is a perspective View of th interior of a building, showing the roof in section and illustrating the preferred method of roof construction;

Fig. 2 is a sectional view of the roof of Fig. 1, showing the same interior arrangement of the braces;

Fig. 3 is a similar view showing the braces applied to the exterior;

Fig. 4 is a sectional view showing tie rods employed in lieu of the interior braces of Fig. 2;

Fig. 5 is a sectional view showing a modified form of construction, in which the depressed roof section hangs perpendicularly below the ends of the girders;

Fig. 6 is a plan view of the girder and beam arrangement illustrated in Figs. 1 and 2, with the roofing removed;

Fig. '7 is a similar plan view of the construction of Fig. 5;

Fig. 8 is a plan view of a modified construction of a roofing similar to that shown in Figs. 1 and 2, but difiering therefrom in that single girders rather than pairs of girders ar employed in the elevated roof structure;

Fig. 9 is a sectional view of a roof in which a 2 section of the roof is elevated rather than depressed;

Fig. 10 is a plan view of a modified roof construction employing a somewhat different arrangement of girders;

Fig. 11 is a sectional view of the roof of Fig. 10;

Fig. 12 is a plan view of a floor construction employing pairs of girders and reinforcing cross beams;

Fig. 13 is a perspective view of the column,

girder and beam arrangement employed in the floor construction of Fig. 12; and

Fig. 14 is a plan view, partly in section, of the same.

Referring first ;to the roof construction of 3.5 Figs, 1 and 2, I have illustrated the interior of a building, in which columns 29 of I beam formation are arranged in rows which are parallel in two directions at right angles to one another. Each column is capped by a plate 2| which affords a support for four radially extending diagonally disposed arms 22 which in conjunction constitute a horizontally disposed cross. While ordinarily the raidial rms will extend at equal angular spacing from one another, it is not essential that such equality be maintained. Each of the arms is supported b a diagonally disposed brace 23 which is secured at its outer end within a fitting 2a which also receives the outer end of the associated radial arm. The braces converge downwardly and inwardly to the column and are connected therewith at a point substantially below the top of the column.

The ends of oppositely disposed pairs of arms allord support for a pair of girders 25, which as shown are of I beam formation, and each row of at least two columns will support a pair of girders, the top of the column terminating at a point intermediate the girders composing a pair. This method of supporting the pairs of girders upon rows which comprise at least two columns spaced from one another insures that the girders will be firmly supported at widely spaced points to sustain the weight of the main roof section which is utilized to counterbalance the weight of the offset deck now to be described. The pairs of girders extend beyond the cross supports, and their aligned ends are secured to a header channel beam 26 by means of plates 21 or the like. The same construction is employed on the opposite side of the space reserved for the depressed roof deck.

As shown in Fig. 1, the ofiset depressed deck is supported upon pairs of girders 28 which run parallel with but at lower level than the pairs of girders 25. The length of the girders 28 is less than the gap between the ends of the girders 25, which provides for a depressed' roof deck section of reduced area, and enables the employment of window sections 29 which are obliquely disposed and convergently arranged on opposite sides of the depressed roof deck to secure a more extended window surface and provide for a more complete distribution of light.

The lower pairs of girders 28 are secured at their opposite ends b downwardly converging hanger bars 39 which constitute tension elements which are secured to the ends of the respective girders 28 by plates 3 I, or in any other convenient manner. As shown in Figs. 1 and 2, the obliquely disposed hanger bars 33 are braced by interior I brace rods 32 which make connection at their upper ends with the associated upper girders 25, although if it is desired to eliminate interior bracing, a similar result may be obtained by providing exterior diagonal brace rods 32 as shown in Fig. 3.

The upper girders 25 support cross beams 33 which may be variously arranged and spaced and which provide support for the upper deck planking 34 or roofing of any desired character. The lower girders 28 likewise support cross beams 35 to which the lower deck roofing 36 is nailed or otherwise secured.

Figs. 4 and 6 illustrate a depressed roof construction which is supported from upper girders identical with those previously described; but in the construction of Figs. 4 and 6 I employ single lower girders 3'! in lieu of pairs of lower girders 28, and the girders 31 are aligned to terminate at points intermediate the ends of adjacent pairs of upper girders, and instead of bracing the lower girders 3'! by brace rods running to the upper girders, I employ ties 38, which extend directly back to the adjacent columns and make connection therewith. This provides a simplified construction Which ma be desirable in cases where such interior bracing at a lower level is not objectionable.

In Fig. I have shown a construction in which the column and upper girder arrangement is identical with that first described, but in this case I have employed a depressed roof section of a width equal to the gap between the ends of the upper girders, so that, in lieu of the obliquely disposed convergent hanger bars 39, I employ vertical hangers 39 which connect with lower girders 4E! and are braced by diagonal braces 4| similar to the interior braces 32 first described, although it will be understood that the method of bracing by exterior braces or by tie rods may be applied to the construction of Fig. 5, and that the same diiIers from the previous constructions only in the fact that the lower deck section has a span equal to rather than less than the gap between the ends of the upper girders.

In Fig. 8 I have shown a modified structure in which single upper girders 42 rather than pairs of girders are employed and in which the girders rest directly upon the tops of columns 43, the cross construction being omitted. In Fig. 8 the lower deck girders 44 are of less length than the gap between the ends of the upper girders, and are suspended from the ends of the upper girders by tension bar hangers 45, the upper ends of which are connected with a header for the aligned ends of the upper girders. The lower deck construction itself may be identical with that shown in Fig. 4, which provides for obliquely disposed converging lines of windows, or the lower deck construction may have the fuller span of Fig. 5. In short, the construction shown in Fig. 8 may employ a. bracing arrangement similar to that of any of the constructions previously described, and difiers therefrom only in the fact that single girders rather than pairs of girders are employed.

In the construction of Fig. 9 I have shown a reversal in the roof arrangement, in that the roof construction between the main girders is elevated rather than depressed. In this construction I have shown upper short girders 4'! which are connected with the ends of the pairs of girders 25 by means of obliquely extending convergent suporting bars 48 which connect the ends of the upper and lower girders and thus serve to provide for the support of an elevated deck having obliquely disposed rows of windows 49. The upper deck may be supported from pairs of girders arranged in the manner first described, or may be supported from the ends of single girders disposed as in Fig. 8.

In Figs. 10 and 11 I have shown a somewhat different girder arrangement for the main roof portion, with ofiset sections of the character shown in Fig. 2, although the offset sections may be of any of the alternate forms previously described.

I employ columns arranged in rows as in the previously described construction, and employ the same cross head arrangement, but in Figs. l0 and II I provide pairs of lower girders 25 which run parallel with the gap provided for the ofiset roof sections, which are supported by the cross heads in the manner previously described, and the lower girders serve to support a series of upper girders 25' which have their ends projecting inwardly beyond the support afforded by the lower girders 25 so that the overhanging ends of the upper girders serve as the points of connection for the hanger bars 30 (or supporting bars 48 as the case may be), which are secured thereto and braced in any one of the various ways previousl described.

The upper overhanging girders correspond in all respects to the girders 25 and serve to support the roof beams 33 and roofing 34, so that in all respects, save in the employment of lower and upper girders, the construction is similar.

In roof construction heretofore described, howsoever modified, the cantilever principle is employed in sustaining the weight or downward thrust of the intermediate roof sections, whether depressed or elevated, since in all cases it will be noted that the ends of the main girders which support the oiIset roof sections are extended be yond the points of support afforded by the columns, so that the weight of the suspended roof sections will be measurably counterbalanced by the weight of the main roofsections which rest directly upon the girders supported by rows of columns, thereby distributing and equalizing the load, and enabling the number of columns to be reduced to a minimum with a corresponding increase in the spacing arrangement throughout the building. The ofiset intermediate roof sections are thus suspended from the projecting ends of girders which are themselves firmly anchored upon a plurality of columns and not merely counterbalanced upon single columns without additional anchorage.

In cases where the depressed deck sections of 3 reduced span are employed with the sloping rows of windows, a highly advantageous lighting arrangement is provided for, in that the area of transparency is increased and the area of shadow beneath the depressed decks is reduced, so that a more even distribution of light is afforded, and that without floor obstruction within the area beneath the depressed deck sections.

Where the main girders are arranged in pairs,

and supported by the cross arrangement at the top of each column, the strength of the con struction is increased not onl by the employment of pairs of girders but by the lateral spreading of the support afforded by each column, so

that the unsupported span between the lines of girders is reduced, thereby affording a more even distribution or the column support throughout the entire roof structure.

Such a girder arrangement by pairs is peculiarly well adapted, by cantilever action, to sus- :4."

tain the weight of the suspended offset roof sections, particularly when the latter, employ the obliquely disposed supporting bars, as in Fig. 1 for example, which places the opposed bars in balanced tension against one another, and which, 1

in conjunction with the cantilever support afforded from above, constitutes a particularly advantageous method of load distribution.

The cantilever arrangement of the girders beyond the column brackets tends to fix the girder ends and thereby produce the equivalent of continuous beam action, thereby permitting the use of considerably lighter material, while the spread of the column brackets beyond the column centers permits the girder beams to be extended further beyond the column centers, thereby reducing the length of the depressed center span.

It is desirable to have the depressed portion of the roof as narrow as permissible for a more even light distribution, and for this reason the suspended portion is further reduced by sloping the supporting suspension bars. This is structurally economical, since a substantial portion of the span between the girder ends is in direct tension instead of bending stress, and in order to counteract the effect of possible unbalanced loading and to provide additional rigidity, tie rods or braces serve to connect the depressed girder sections to the columns in opposite directions.

By varying the shape or slope of the sides, any desired width may be provided for light disturbution, without increasing or decreasing the cantilever tension of the main girder, which affords a decided advantage over a construction employing the straight vertical sides for window lighting.

In many cases, single main girders may be employed, as in Fig. 8, by reason of the fact that the suspended girder span is much reduced by sloping. the supporting. sides, and by reason of the fact that the pair of girders which support the depressed deck section are placed on column lines, and are strongest at this point by reason of the comparatively short span between the ends of the main girders.

It is preferred to make the header beams which connect the ends of the main girders long enough to engage four girders so as to provide added transverse rigidity, and it is also desirable to alternate or stagger the joints in the roof beams to afford added rigidity.

The entire construction is one which aiTords great rigidity in all directions in ratio to the amount of material employed, and at the same time permits of considerable variation in detail in respect to the size, slope and arrangement of the window sections, and the dimensions of the windows and the dimensions of the offset roof deck, to accommodate local conditions or pro vide for a most advantageous distribution of light.

Similar principles, as applied to floor construction, are illustrated in Figs. 12, 13 and 14. In the construction there shown, continuous vertical columns 50 are employed, which are of I-beam construction and which may extend from floor to floor. At each floor level the column has mounted thereon upper and lower rectangular spaced plates 5| and 52 respectively, each of which is provided with an I-shaped aperture 53 to permit the plates to be placed onto the columns and secured thereto in properly spaced relation by welding or the like.

The upper and lower plates afford mountings for diagonally extending arms 5s of I-beam formation, the inner ends of which lie between and project radially from the corners of the upper and lower plates, being preferably secured thereto and to the contiguous edges of the column flanges by welding or the like. Each of the arms, at its outer end, has its upper and lower flanges cut away to afiord an obliquely disposed edge 55 with the web of the arm extended and connected to an angularly disposed plate 56 adapted to be secured by rivets 57 or the like to the web of an I-beam girder 5B, the girders being arranged in pairs on opposite sides of the columns.

In order to afford proper bracing between the rows of columns, and to make provision for the uniting of the ends of girder sections, I employ cross beams 53 of I-beam formation, as shown in Fig. 14, which extend at right angles to the girders 53. It will be noted that the upper girder sections in Fig. 14 terminate on opposite sides of the cross beam, which aiiords a union for the ends of the girder sections. To effect such a union. the web ends Gil of the girders are extended into abutting relation with the web of the cross beam and are secured thereto by angles El, which may be riveted or welded in place. The inner end of the cross beam is entered between plates 5i and 52, and abuts against the outer free face of the adjacent flange of the column, and is secured thereto by angles 52.

.As shown in Fig. 12, the cross 53 are arranged in staggered relation with respect to the rows of columns. As there shown, the lower and upper cross beams connect the middle and right hand rows of columns, while the intermediate cross beam 59 connects the middle and left hand rows of columns, thus ailording an efiective and evenly distributed form of connection for tying together and uniting the floor structure throughout the building, so that lateral or bending stresses imposed upon the columns will be resisted by the entire structure. At the same time, adequate provision is made for uniting the ends of the girder sections at the points where the structure is most completely reinforced by the cross beams, so that extreme rigidity is provided by the use of a reduced weight of material and at the same time, Without the employment of braces or like reinforcing elements which project below the upper and lower levels of the floor.

The girder construction thus provided affords support for floor beams 63, which span the girders and are preferably arranged to have the ends of the beam sections in staggered relation, as shown in the upper portion of Fig. 12, although, if desired, the arrangement may be that shown in the lower portion of Fig. 12, in which the beam sections at the left extend continuously across two adjacent rows of girder sections without staggering, and have their ends joined to shorter beam sections which span the intervening space between the next pair of girders. The arrangement of the floor beams will be dictated by local conditions in the floor structure, but where it is desired to equalize the reinforcement throughout the entire floor to the greatest possible extent, the staggered arrangement of the beams will be preferable, in that the floor beams will thus supplement the bracing and tying together of the structure throughout. The floor beams may rest upon the girders, as shown throughout the main portion of Fig. 12, or have their ends supported between the girder flanges, as shown at the upper right of said figures.

The fioor construction above described permits the economical use of relatively shallow beams, all of which may be of the same depth, thereby avoiding the employment of deep girder beams of the character commonly employed. The rigidity afforded at each column makes the construction what is known as a rigid frame and the distribution of stresses which this eiiects results in a considerable saving of material. This rigidity is particularly advantageous in tall buildings where wind stresses must be considered, in that little, if any, additional bracing need be employed.

The column bracket arms are made an integral part of the column by riveting or welding, and

although a cross formation is employed, the arms need not necessarily be normal to each other, but are proportioned to suit the column spacing on both directions, thereby eliminating the employment of brackets which extend below the main girders.

The end of each arm, being connected to the associated girder, provides each girder with two separated points of connection at each of its ends, and since the cross is an integral part of the column, it is evident that any lateral displacement in the direction of the girder, or an unbalanced moment condition at the columns, is resisted by both the columns and girders, which results in economy of material and rigidity without the necessity for bracing.

In the floor construction, the girders will ordinarily be made in two panel lengths with joints alternating at the columns, where the cross beam connects the column with an adjoining column in the next row. This arrangement provides rigidity in a direction transverse to the girders and serves to resist unbalanced moments at the columns in this direction. The arrangement also makes the ends of the girders fixed by reason of the end leverage between the connection of the cross arms to the girder and the connection of the girder to the beam, and provides continuous beam action in the girder. Due to the method of connecting columns, cross beams and girders to each other, a rigid frame construction is provided which results in economy of material and the rigidity which such a construction affords.

Although the invention has been described with particularity as to detail, it will be understood that numerous variations may be made therein without departing from the spirit of the invention.

I claim:

1. In a roof construction, the combination of a plurality of rows of columns on each side of a gap provided for the reception of an ofiset roof deck, said rows extending parallel with the edges of said gap and also backwardly therefrom, main girders extending toward said gap and terminating on opposite sides thereof and finding support in each case upon a plurality of columns in row alignment extending backwardly from said gap, said girders having their ends projecting inwardly toward said gap and beyond the proximate points of support, vertically offset deck girders, connecting means supported from the projecting ends of the main girders and connecting with the offset deck girders for supporting the latter, roofing material overlying the main girders and the oiiset deck girders, and window glazing extending between the main and offset roof levels.

2. In a roof construction, the combination of a plurality of rows of columns on each side of a gap provided for the reception of an offset roof deck, said rows extending parallel with the edges of said gap and also backwardly therefrom, main girders extending toward said gap and terminating on opposite sides thereof and finding support in each case upon a plurality of columns in row alignment extending backwardly from said gap, said girders having their ends projecting inwardly toward said gap and beyond the proximate points of support, vertically offset deck girders of lesser length than the span between the opposed ends of the main girders, connecting means supported from the projecting ends of the main girders and connecting with the offset deck girders for supporting the latter, roofing material overlying the main girders and the offset deck girders, and window glazing sloping between the main and offset roof levels.

3. In a roof construction, the combination of a plurality of rows of columns on each side of a gap provided for the reception of a lower roof deck, said rows extending parallel with the edges of said gap and also backwardly therefrom, main girders extending toward said gap and terminating on opposite sides thereof and finding support in each case upon a plurality of columns in row alignment extending backwardly from said gap, said girders having their ends projecting inwardly beyond the proximate points of support, lower deck girders, suspending means supported from the projecting ends of the main girders and connected with the lower deck girders for suspending the latter, roofing material overlying the main girders .and the lower deck girders, and window glazing extending between the upper and lower roof levels.

4. In a roof construction, the combination of a plurality of rows of columns on each side of a gap provided for the reception of a lower roof deck, said rows extending parallel with the edges of said gap and also backwardly therefrom, main girders extending toward said gap and terminating on opposite sides thereof and finding support in each case upon a plurality of columns in row alignment extending backwardly from said gap, said. girders having their ends projecting inwardly beyond the proximate points of support, lower deck girders of lesser length than the span between the opposed ends of the main girders, suspending means supported from the projecting ends of the main girders and connected with the lower deck girders for suspending the latter, roofing material overlying the main girders and the lower deck girders, and window glazing sloping between the upper and lower roof levels.

5. In a roof construction, the combination of a plurality of rows of columns on each side of a gap provided for the reception of an offset roof deck, said rows extending parallel with the edges of said gap and also backwardly therefrom, pairs of main girders extending toward said gap and terminating on opposite sides thereof, each pair extending inwardly beyond the associated terminal column of a row extending backwardly from said gap and with the columns of said row extending to points intermediate the companion girders of the pair, a cross head secured to the column and having arms extending radially therefrom and connected to the proximate girders of the pair on opposite sides of the column, offset deck girders, supporting means secured to the projecting ends of the main girders and connected with the offset deck girders for supporting the latter, roofing material overlying the main girders and the offset deck girders, and window glazing extending between the upper and lower roof levels.

6. In a roof construction, the combination of a plurality of rows of columns on each side of a gap provided for the reception of an offset roof deck, said rows extending parallel with the edges of said gap and also backwardly therefrom, pairs of main girders extending toward said gap and terminating on opposite sides thereof, each pair extending inwardly beyond the terminal associated column of a row extending backwardly from said gap and with the columns of said row extending to points intermediate the companion girders of the pair, a cross head secured to the column and having arms extending radially therefrom and connected to the proximate girder of the pair on opposite sides of the column, offset deck girders of lesser length than the span between the opposed ends of the main girders, supporting means secured to the projecting ends of the main girders and connected with the offset deck girders for supporting the latter, roofing material overlying the main girders and the offset deck girders, and window glazing sloping between the upper and lower roof levels.

7. In a roof construction, the combination of a plurality of rows of columns on each side of a gap provided for the reception of a lower roof deck, said rows extending parallel with the edges of said gap and also backwardly therefrom, pairs of main girders extending toward said gap and terminating on opposite sides thereof, each pair extending inwardly beyond the associated terminal column of a row extending backwardly from said gap and with the columns of said row extending to points intermediate the companion girders of the pair, a cross head secured to the column and having arms extending radially therefrom and connected to the proximate girders of a pair on opposite sides of the column, lower deck girders, suspending means supported by the projecting ends of the main girders and connected with the lower deck girders for suspending the latter, roofing materialoverlying the main girders and the lower deck girders, and window glazing extending between the upper and lower roof levels.

8. In a roof construction, the combination of a plurality of rows of columns on each side of a gap provided for the reception of a lower roof deck, said rows extending parallel with the edges of said gap and also backwardly therefrom, pairs of main girders extending toward said gap and terminating on opposite sides thereof, each pair extending inwardly beyond the associated terminal column of a row extending backwardly from said gap and with the columns of said row extending to points intermediate the companion girders of the pair, a cross head secured to the column and having arms extending radially therefrom and connected to the proximate girders of a pair on opposite sides of the column, lower deck girders of lesser length than the span between the opposed ends of the main girders, suspending means supported by the projecting ends of the main girders and connected with the lower deck girders for suspending the latter, roofing material overlying the main girders and the lower deck girders, and window glazing sloping between the upper and lower roof levels.

9. In a roof construction, the combination of a plurality of rows of columns on each side of a gap provided for the reception of a lower roof deck, said rows extending parallel with the edges bf said gap and also backwardly therefrom, pairs of main girders extending toward said gap and terminating on opposite sides thereof, each pair extending inwardly beyond the associated terminal column of a row extending backwardly from said gap and with the columns of said row extending to points intermediate the companion girders of the pair, a cross head secured to the column and having arms extending radially therefrom and connected to the proximate girders of a pair on opposite sides of the column, lower deck girders, suspending means supported by the projecting ends of the main girders and connected with the lower deck girders for suspending the latter, roofing material overlying the main girders and the lower deck girders, window glazing extending between the upper and lower roof levels, and brace members affording connection between the lower deck girders and the adjacent columns.

10. In a roof construction, the combination of a plurality of rows of columns on each side of a gap provided for the reception of a lower roof deck, said rows extending parallel with the edges of said gap and also backwardly therefrom, pairs of main girders extending toward said gap and terminating on opposite sides thereof, each pair extending inwardly beyond the associated terminal column of a row extending backwardly from said gap and with the columns of said row extending to points intermediate the companion girders of the pair, a cross head secured to the column and having arms extending radially therefrom and connected to the proximate girders of a pair on opposite sides of the column, lower deck girders of lesser length than the span between the opposed ends of the main girders, suspending means supported by the projecting ends of the main girders and connected with the lower deck girders for suspending the latter, roofing material overlying the main girders and the lower deck girders, window glazing sloping between the upper and lower roof levels and brace members affording connection between the lower deck girders and the adjacent columns.

11. In building construction, the combination of a row of columns, a pair of girders supported by the columns and spaced to bring the columns into intermediate relation between the girders, each column being provided with a cross head consisting of radiating arms connected at their outer ends to the proximate girders, upper and lower plates secured to the column and spaced to receive the inner convergent ends of the arms between the plates, and a reinforcing transverse beam intersecting one of the girders of a pair with its imier end interposed and secured between the plates and between the convergent inner ends of adjacent arms and with its outer end beyond the intersected girder connected to other portions of the building structure.

12. In building construction, the combination of at least two rows of columns and at least two pairs of girders, each pair supported by a row of columns and spaced to bring the columns of the row into intermediate relation between the girders of the pair, connecting means carried by each column and extending outwardly therefrom for supporting the companion girders of a pair on opposite sides of the column, and reinforcing transverse beams extending between the proximate columns of adjacent rows and having their ends connected therewith, each beam intersecting the proximate girders of adjacent pairs to afford rigid reinforcement between the rows of columns.

13. In building construction, the combination of at least two rows of columns and at least two pairs of girders, each pair supported by a row of columns and spaced to bring the columns of the row into intermediate relation between the girders of the pair, each column being provided with a cross head consisting of diagonally extending radiating arms connected at their outer ends to the proximate girder of the associated pair, upper and lower plates secured to the columns and spaced to receive the inner converging ends of a set of arms between the plates, and reinforcing transverse beams extending between the proximate columns of adjacent rows and having their ends entered and secured between the upper and lower plates and between adjacent radiating arms, each beam intersecting the proximate girders of adjacent pairs to afford rigid reinforcement between the rows of columns.

14. In building construction, th combination of at least three rows of columns and at least three pairs of girders, each pair supported by a row of columns and spaced to bring the columns of the row into intermediate relation between the girders of the pair, means carried by each column and extending outwardly therefrom for supporting the companion girders of a pair, and reinforcing transverse beams extending between the proximate columns of adjacent rows and having their ends connected therewith, each beam intersecting the proximate girder of adjacent pairs to afford rigid reinforcement between the rows of columns, and the transverse beams alternately connecting the columns of the middle row with the proximate columns of the laterally adjacent rows to afford a staggered reinforcing arrangement.

15. In building construction, the combination of at least three rows of columns and at least three pairs of girders, each pair supported by a row of columns and spaced to bring the columns of the row into intermediate relation between the girders of the pair, each column being provided with a cross head consisting of diagonally extending radiating arms connected at their outer ends to the proximate girder of the associated pair, upper and lower plates secured to the columns and spaced to receive the inner converging ends of a set of arms between the plates, and reinforcing transverse beams extending between the proximate columns of adjacent rows and having their ends entered and secured between the upper and lower plates and between adjacent radiating arms, each beam intersecting the proximate girders of adjacent pairs to afford rigid reinforcement between the rows of columns, and the transverse beams alternately connecting the columns of the middle row with the proximate columns of the laterally adjacent rows to afford a staggered reinforcing arrangement.

. ABRAM MACMILLAN.

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