Title:
Steel floor construction
United States Patent 2084648


Abstract:
A primary object of this invention is to provide an improved structural steel floor construction for buildings which will have the required strength and rigidity with materially less weight of steel than has heretofore been used in steel building construction. This is accomplished in general...



Inventors:
Abram, Macmillan
Application Number:
US71717934A
Publication Date:
06/22/1937
Filing Date:
03/24/1934
Assignee:
Abram, Macmillan
Primary Class:
Other Classes:
52/648.1
International Classes:
E04B5/43
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Description:

A primary object of this invention is to provide an improved structural steel floor construction for buildings which will have the required strength and rigidity with materially less weight of steel than has heretofore been used in steel building construction.

This is accomplished in general by using a pair of girders spaced one on each side of each row of columns and so constructed and supported as to give each girder the effect of being continuous throughout its length, and of further stiffening and strengthening it by spreading or enlarging the column brackets so as to materially shorten the unsupported girder span. By this arrangement too the beams connecting the girders are.shortened, thereby permitting them to be made of lighter sections. Also some of the beams Sadjacent the columns are carried directly thereon and, though made up of shorter lengths, are secured together by heavy splice plates, so that they virtually become continuous cross girders having the same strength and rigidity throughout their length. The panel thus provided is of much smaller dimensions than that between columns.

Referring to the drawings: Figure 1 is a plan view of a portion of a floor embodying one form of the invention; Fig. 2 is a partial enlarged plan view of the moment splice of Fig. 1 showing the top splice plate removed; Fig. 3 is a similar view of the flange splices of Fig. 1; Fig. 4 is a view on the line 4 of Fig. 3; Fig. 5 is a partial enlarged plan view of the crossing girders showing their attachment to the column; Fig. 6 is a view similar to Fig. 1 showing a modified form of the invention; Figs. 7 and 8 are partial enlarged details of column support taken on lines 7 and 8 of Figs. 1 and 5; and Pig. 9 is a view similar to Fig. 6 showing another modification of the invention.

The embodiment illustrated in Fig. 1 comprises a steel floor construction supported on inside columns A, and includes spaced girders 10, II in one direction located on opposite sides of one line of columns, and spaced cross girders 12, 13 on opposite sides of the columns at right angles to the first line of girders.

The girder 10 is made up of structural sections, preferably I-beams, 10a, 10b, 10, etc., secured together by means of riveted moment splice plates B (Fig. 2) above and below the sections in a well known manner, the webs of the i-oeanmi being secured together by connecting angles 14.

The girder II is ilkewise made up of a plurality of structural members set end to end and connected by means of moment splice plates, so that the girders have substantially the same moment of resistance throughout their length and result in continuity of action in the girders.

It will also be observed that girder sections S19 and Ilb as illustrated in Fig. 1 are of two iu panel lengths. If desired, they could be of three or more panel lengths, or they could be of a single panel length. In this type they are preferably multiples of panel lengths.

The cross girder 12 is made up of a number of relatively short I-beam members 12a, 1, 12, I, 12d, 12e, etc., which are also connected by means of moment splice plates B, flange splice plates C, and connecting angles. The girder 13 is made up in the same way. Cross girders 5 and 16 are similar to cross girders 12 and 13, except that no moment splice plates B are used, all the splices being made by means of flange splice plates C.

The flange splice plate C is used as shown in Fig. 3 for tying two cross girders where they stop on opposite sides of a continuous girder, whereas the moment splice plate 13 (Fig. 2) is used for securing together the meeting ends of four girder members. In all cases, however, the full strength and rigidity of the girder sections are preserved by these splice plates.

This system of spaced crossed girders is secured to the supporting columns A by means of column brackets 17, 18, which are secured to the girder members 12b, 13bby means of connecting angles 19. The column brackets are secured to the column by supporting angles 20, 21, the latter being reinforced by an angle member 22 riveted to the column.

This provides a panel bounded by the girders 11, 15, 10 and 13 which is of much less area than that afforded by the column spacing. This panel is divided by beams 23, 24, which are secured at their ends to the girders by connecting angles which are not shown in detail as they are common practice and are similar to angles 14.

The splice plates have been removed in certain figures, particularly Fig. 6, to show more clearly how the girders are arranged.

Any desired unsupported length of girders or beams can be had by making the lengths of brackets, as 12b and 7, between pairs of girders to suit.

The longer the brackets, the shorter the unsupported lengths of girders and beams.

This arrangement of girders in spaced pairs has certain outstanding advantages from the standpoint of the structural engineer. For example, (1) it permits the girders to be calculated as continuous beams (which is much stronger and stiffer for a given spacing and loading than is a beam having the same section and supported at its ends), (2) the unsupported length of the girder is reduced by spacing the cross girders at the column, thereby further reducing the required weight of girder for a given column spacing and loading, (3) the length of the beams 23, 24 being likewise reduced, these beams can be much lighter. Thus the weight of girders and beams being less reduces the dead load on the columns which can in turn be made lighter, thereby greatly reducing the total weight of steel in a building.

This system of framing is designed to carry any suitable floor deck (not shown) such as tile or concrete, which are assembled in the frame in any well known manner.

Another decided advantage of this system is that it leaves the spaces between the columns and in line therewith free, thereby providing ample and unobstructed "pipe spaces" for the insertion of water, steam and waste pipes, etc. It is common practice to place the permanent partitions on the column lines and to place the piping therein. Thus "pipe spaces" have to be provided for in the building as constructed but the presence of steel girders between columns makes changes in the piping difficult after the building is completed. The present construction is ideal in this respect in that it permits easy changes in the piping at any time because of the absence of girders at the partitions.

In Fig. 6 is shown a modification of the invention in which the spaced girders in both directions are made up of girder sections each of a panel length arranged so that they cross each other intermediate the length of each section so that flange splice plates top and bottom and the connecting angles are all that is needed to carry the full strength of each section across the splice and provide the equivalent of a continuous girder supported at points intermediate its length. The spaced girders I10, 111 are made up of sections i10l , I 0b, 1IO0, etc., and Ilia, iflb, IIle, etc., and these are crossed by girders 112, 113, made up of sections I i2a, 112b, 112c, 112d. These intersecting girders are carried on the inside columns A', A' by means of column brackets 117, 118 which are secured to the column and to the cross girders in the same manner as the column brackets 17, 18, Figures 7 and 8 being identical for the two frame constructions. The crossing girders are connected by flange splice plates C' and by connecting angles riveted to their webs, as shown in Figs. 3 and 4. Figs. 7 and 8 apply also to Fig. 6 except for differences in reference numerals.

The corner column A2 and the side columns A3 carry side girders 119, 120 which are preferably in line with these columns and which may be made much deeper and heavier than the inside girders, particularly on tall buildings where wind loads must be provided for. The manner of securing these outside girders to columns by connecting angles is not illustrated as it is well known. The same is true of the connections between beams 123, 124 and the girders. The framing at the outside columns preferably follows that described for the inside columns and will be clearly understood from Fig. 6 in which most of the flange splice plates C have been omitted for clearness. The girders spaced just inside the outside columns A3 and A4 may be omitted, if desired, and the girders and beams carried to the side girders I19, etc. The construction of Fig. 6 has the advantage of reducing the number of different members to be used in a given floor since they are largely duplicates for a uniform column spacing.

In Fig. 9 is shown another modification of the invention similar to Fig. 6 in which the beams 123, 124 (Fig. 6) are omitted, and in which the girders 210, 2 1, 212 and 213 are equally spaced to form panels D, E, F, G, H, etc., which are preferably square and of equal area. Thus the column brackets 217, 218 are attached to the columns and girders, as shown in Figs. 7 and 8, but now have a length of about half the column spacing. These panels can be economically filled with a flat slab of concrete and reinforced with steel rods crossed to lie in both directions of the slab. If desired, the crossed girders 210, 212, etc., may be supported by column brackets in the form of an X running diagonally both ways of the panel G and attaching to the girders at their points of intersection. A continuous girder or beam supported intermediate its length as is herein shown and described is calculated as a beam "fixed at both ends" with greatly increased strength and rigidity, whereas in the usual steel building construction each girder section ends at a column and hence can only be calculated as a beam "supported at both ends".

The girders could be placed against the sides of the columns and obtain the benefit of con- -5 tinuity of action, but to do so would sacrifice some of the advantages of having them spaced from the columns as pointed out above.

Thus it will be seen that this construction permits the use of beams and girders of the same depth throughout so that no girders extend below the ceilings. Thus partition walls can now be placed without regard to the location of floor girders or beams.

While I have shown and described but a few embodiments of my invention, it is to be understood that it is capable of many modifications.

Changes, therefore, in the construction and arrangement may be made which do not depart from the spirit and scope of the invention as disclosed in the appended claims.

I claim: 1. A steel building construction comprising spaced columns arranged in rows, main loadcarrying girders arranged in pairs, one on each side of each row of inside columns and spaced therefrom, to the exclusion of main load-carrying girders on the center line of columns, cross beams carried by the main girders, and means for supporting the girders on the columns, each main girder being made up of sections spliced together in alignment so as to develop the full strength of the girder so that each girder has continuity of action throughout its length.

2. In a structural steel floor construction, spaced columns arranged in rows, main loadcarrying girders arranged in pairs, one girder on each side of each row of inside columns and spaced therefrom, to the exclusion of main loadcarrying girders on the center line of columns, cross girders similarly arranged at right angles to the first-mentioned girders, the girders being spliced at the points of intersection so as to develop the full strength of all the girders across said points so that the girders have continuity of action throughout their length, and means for supporting the girders on the columns.

3. In a structural steel floor construction, spaced columns arranged in rows, main loadcarrying girders arranged in pairs, one girder on each side of each row of inside columns, to the exclusion of main load-carrying girders on the center line of columns, cross girders similarly arranged at right angles to the first-mentioned girders, the girders being spliced at the points of intersection so as to develop the full strength of all the girders across said points so that the girders have continuity of action throughout their length, and means for supporting the girders on the columns, said girders being uniformly spaced to provide panels of about one-fourth the area of that between columns.

4. In a structural steel floor construction, spaced columns arranged in rows, main loadcarrying girders arranged in pairs, one on each side of each row of inside columns and spaced therefrom, to the exclusion of main load-carrying girders on the center line of columns, column brackets for securing the girders to the columns but spacing the girders from the columns so as to reduce the distance between adjacent girders of adjacent rows of columns, and spaced beams connecting a girder of one pair with the nearest girder of the next pair.

5. In a structural steel floor construction, spaced columns arranged in rows, main loadcarrying girders arranged in pairs, one on each side of each row of inside columns and spaced therefrom, to the exclusion of main load-carrying girders on the center line of columns, column brackets for securing the girders to the columns but spacing the girders from the columns so as to reduce the distance between adjacent girders of adjacent rows of columns, and spaced beams connecting a girder of one pair with the nearest girder of the next pair, the girders being supported at points intermediate the columns.

6. In a structural steel floor construction, spaced columns arranged in rows, main loadcarrying girders arranged in pairs, one on each side of each row of inside columns, and spaced therefrom, to the exclusion of main load-carrying girders on the center line of columns, column brackets for securing the girders to the columns but spacing the girders from the columns so as to reduce the distance between adjacent girders of adjacent rows of columns, and spaced beams connecting a girder of one pair with the nearest girder of the next pair, the length of certain of the girder sections being equal to a plurality of column spacings.

7. In a structural steel building construction, spaced columns arranged in rows at right angles to each other, main load-carrying girders arranged in pairs, certain of said pairs being at right angles to the others, one of each lying on each side of one row of inside columns, to the exclusion of main load-carrying girders on the column lines, said girders being secured to each other at the points of intersection so as to develop the full strength of each girder across the point of intersection, and means for supporting certain of said girders on the columns at points between the columns.

8. In a structural steel building construction, spaced columns arranged in rows at right angles to each other, main load-carrying girders arranged in pairs, certain of said pairs being at right angles to the others, one of each pair lying on each side of one row of inside columns, to the exclusion of main load-carrying girders on the column lines, said girders being secured to each other at the points of intersection so as to develop the full strength of each girder across the point of intersection, one member of each intersecting pair passing continuously through the point of intersection, and means for supporting certain of said girders on the columns at points between the columns.

9. A structural steel floor construction comprising a series of longitudinal girders and a series of transverse girders intersecting to form parallelograms, means for securing girder sections at the points of intersection whereby the full strength of the girder extends through said points of intersection, columns extending to points within certain of said parallelograms, preferably substantially centrally thereof, and brackets mounted on the columns and connected to certain of the girders whereby the girder structure is supported on the columns, all to the exclusion of main load-carrying girders on the center lines of the columns.

10. A steel floor construction supported on columns, said construction comprising a group of four girders spaced from a supporting column and arranged about the same to form a parallelogram, one end of each girder terminating at a point intermediate another girder of the group and secured thereto, and means for supporting said girders on the column within the parallelogram.

11. A steel floor construction supported on columns arranged in rows longitudinally and transversely and comprising a group of four girders spaced from a supporting column and arranged about the same to form a parallelogram, one end of each girder terminating at a point intermediate another girder of the group and secured thereto, and means for supporting said girders on the column within the parallelogram, the other end of each girder terminating at a point intermediate a girder of another group to which it is secured.

12. A steel floor construction supported on columns arranged in rows longitudinally and transversely and comprising a group of four girders spaced from a supporting column and arranged about the same to form a parallelogram, one end of each girder terminating at a point intermediate another girder of the group and secured thereto, and means for supporting said girders on the column within the parallelogram, the other end of certain of said girders being secured to a girder of another group of four girders at a point intermediate the length of the last mentioned girder.

13. In a floor construction, a row of columns, a main load-carrying girder longer than the column spacing and passing two columns in a row and spaced therefrom, means for firmly anchoring said girder at points beyond said two columns and means carried by said two columns for anchoring said girder at two intermediate points between the columns whereby the girder has fixed ends and has an effective unsupported length considerably less than the distance between columns, said anchoring means and said girders being in the same plane.

14. In a floor construction, a row of columns, a main load-carrying girder longer than the column spacing and passing two columns in a row and spaced therefrom, means for firmly anchoring said girder at points beyond said two columns and means carried by said two columns for anchoring said girder at two intermediate points between said two columns whereby the girder has fixed ends and has an effective unsupported length considerably less than the distance between columns, and cross beams secured to the girder at the two intermediate points and two other cross beams secured to the girder at spaced points between the first-mentioned cross beams.

15. In a floor construction, a row of columns, a main load-carrying girder composed of sections in end-abutting relation, these sections being so connected as to form a girder substantially having continuity of action throughout, said girder passing two columns in a row and spaced therefrom, means carried by said columns for firmly anchoring said girder at points beyond the columns and means carried by said columns for anchoring said girder at two intermediate points between said two columns whereby said girder has an effective unsupported length considerably less than the distance between columns, a second row of columns, a second main load-carrying girder similar to the first and similarly carried by the second row of columns, the two girders facing each other on adjacent sides of the rows, and cross beams of considerably less length than the column spacing connected at their ends to the girders.

16. In a floor construction, a row of columns, a main load-carrying girder composed of sections in end-abutting relation, these sections being so connected as to form a girder substantially having continuity of action throughout, said girder passing two columns in a row and spaced therefrom, means carried by said columns for firmly anchoring said girder at points beyond the columns and means carried by said columns for anchoring said girder at two intermediate points between said two columns whereby said girder has an effective unsupported length considerably less than the distance between columns, a second row of columns, a second main load-carrying girder similar to the first and similarly carried by the second row of columns, the two girders facing each other on adjacent sides of the rows, cross beams of considerably less length than the column spacing connected at their ends to the girders at the two intermediate points, and two other cross beams secured to the girder at points intermediate the first-mentioned cross beams.

17. In a structural steel floor construction, spaced columns arranged in rows, main loadcarrying girders arranged in pairs, one girder on each side of each row of inside columns and spaced therefrom to the exclusion of main loadcarrying girders on the center line of columns, cross girders similarly arranged at right angles to the first-mentioned girders, the girders being secured together so as to develop the full strength of all the girders across said points so that the girders have continuity of action throughout their length, and means for supporting the girders on the columns.

ABRAM MAcMILLAN