US1986999A - Floor structure - Google Patents

Description

Jan. 8, 1935. E. w BURGESS. 1,986,999

FLOOR STRUCTURE Filed Nov. 19, 1952 2 Sheets-Sheet l INVENTOR.

Edward W Bur c ess.

L4 QM ATTORNEY.

Jan. 8, l935.- E. w. BURGESS 1,986,999

1-"LO0R STRUCTURE Filed Nov. 19', 19:52 2 Shasta-Sheet 2 ft If: I I? .111 IEIYEH INVENTOR. Edwafcl WBufgess at/l ATTORNEY.

Patented Jan. 8, 1 935 UNITED STATES.

FLOOR STBUQI'UBE Edward w. Burgess, Milwaukee, Wis., mine: to A. 0. Smith Corporation, Milwaukee, Wis., a

corporation of New York Application November 19, 1932, Serial No. 643,478

4Glalml The invention relates generally to floor structures and more particularlyto floor structures suitable for bridges.

In the present types of composite floor structures comprising steel and the various kinds of fills employed, the weight of the structure per square foot of area is heavier than it need be, because the steel utilized is not'evenly distributed so as to give balanced stresses in tension and compression on the opposite sides of the neutral axis. Further unless there is a substantial thickness of the fill, for example in the case of concrete about three inches, it will crack and portions will become dislodged leaving holes in the surface. Such masses of fill require a heavy frame structure to carry the dead load.

The objectv of the invention is to provide for an even distribution of the steel in a floor structure to obtain substantially balanced stresses in tension and compression.

It is also an object of the invention to provide for the efficient use of the metalto obtain great strength from the weight of steel employed.

Another object of the invention is to provide a bridge floor-in which the amount of fill is not great, thereby obtaining a light structure.

For a fuller understanding of the nature and objects of the invention, reference may be had to the following detailed description taken in conjunction with the accompanying drawings, in

which: I

Figure 1 is a perspective view of a section of a floor constructed in accordance with this invention;

Fig. 2 is a top plan view of a section of the floor structure illustrated in Fig. 1 before the fill is added Fig. 3 is a view in cross-section of a portion of the bridge structure showing details of the construction;

' Fig. 4 is a view in cross-section of a portion of the floor structure at a joint showing the manner in which the units of. the floor structure are united;

Fig. 5 is a top plan view of the floor structure showing a number of the pan sections assembled and welded to one another; and

Fig. 6 is a diagrammatic view of a section of the pan illustrating the even distribution of the steel.

Referring now to the drawings, and Fig. 1 in particular, the stringers 10' illustrated may be part of a bridge structure not shown or any other frame provided for carrying a floor. The size and spacing of the stringers will depend upon the conditions to be met.

The 'bridge floor comprises a plurality of crimped plates or pans 11 extending transversely of the stringers '10 and welded thereto, as shown at 12, for the purpose of retaining them in position. The term pan may properly be applied tothese crimped plates 11 becausethey are provided with rectangular trough-sections 13 which are alternately inverted, the trough-sections facing upwardly being utilized for holding a flll.

Pans or crimped plates 11 of. any desired size may be fabricated. The conditions to be met in the floor structure will generally determine the size. For ordinary bridge structures which the maximum tension and compression stresses should not exceed, 16,000 pounds per square inch, the pans will be fabricated from quarter-inch steel plate and will be about three feet wide and any length to suit the stringer spacing.

The troughs or crimps will be made substantial- 1y rectangular in shape and will be about three inches deep and six inches wide. In forming the corners 14, the steel will be pressed to conform to an arc of a circle, the radius of which will be about of an inch.

In order to obtain high efliciency in the use of the metal in the crimped plates or pans, the side walls of the trough sections are disposed substantially perpendicular to the plane of the pans. Exact perpendicularity is not essential since tests have demonstrated that very excellent results are obtained when the side walls of the trough sections are inclined at an angle of eight degrees or less on either side of the perpendicular to the plane of the pan. As the sides of .the trough sections, are approximately perpendicular, to the top and bottom, substantially rectangular troughs are formed.

The pans or crimped plates may be economically fabricated-by the use of large presses or rolls. With proper machines and carefully constructed tools, the pans may be made very accurately and without damage to the metal.

In order to facilitate erection, one side of each pan is provided with an offset, as shown at 15. The plate is offset one-fourth of an inch which is the thickness of the steel from which the pan is fabricated. In assembling, the offset portion 15 of one pan overlaps the next adjacent 'pan. The pans may therefore be moved relative to one another short distances without opening a gap between them. In this manner the pans may be adjusted on the stringers to compensate for any slight inaccuracies that may occur in the fabrication or erection of the bridge structure.

In the designing of bridges it often happens that the spans are of different lengths and standard floor sections cannot be employed in all the.

spans. With a pan constructed in accordance with this invention the offset flange permits the moving of the pans relative to one another to cover different areas and standard pans may be used on spans of difierent lengths.

An example of how the pans or crimped plates 11 may be assembled on different spans of a bridge by moving the pans of each pair one-half inch farther apart or one-half inch closer together than in the 27-foot span, the respective spans may be covered. 1 After the pans are assembled, they are welded together along the longitudinal joint 16, the weld being made strong enough to transmit stresses in shear. In this instance the welds are shown along the edge of the offset portion 15 but the joint may be welded from underneath or the 0H- set portion may be spot welded to the next adjacent pan.

In designing a bridgefioor, the length of the pan will be selected so that if it is necessary to set them end-to-end, they will meet over a stringer, as shown in Fig. 5. when the pans are thus assembled, they will be welded end-to-end, as shown at 17 in Figs. 4 and 5, thereby providing a unitary structure.

Any suitable grid or armoring 18 may be mounted on the pans 11, as shown in Figs. 1, 2, and 3. The grid shown in Patent No. 1,765,652 is well suited to this floor structure. This grid would be made about one inch deep.

After the pans have been assembled and welded to the stringers, the grid or armoring 18 is mounted on the downwardly facing trough sections and welded thereto as shown at 19. In this instance, the feet of the grid are shown welded to the inverted trough. The welding may be readily eflected by the use of an arc.

Many different kinds of fill 20 may be utilized. The preferred fill is concrete such as used in the building of highways. When concrete is selected for the fill, it may be poured after the grid has been placed in position.

Irrespective of. the kind of fill employed, enough will be utilized to bring it flush with the top of the grid. In this manner a combination tread surface will be provided. When agrid such as shown in Patent No. 1,765,652 is employed, about 10% of the surface area will be steel. This gives a very excellent wearing surface. v

After the fill has been applied, the floor comprises the pan, suiiicient fill to fill the upwardly facing trough members and provide alayer about one inch above the tops of the pans, and a grid embedded in the layer of fill above the pans. The grid will hold the fill. I

When concrete is used as 'a a very rigid structure is obtained. The concrete in the trough-sections supports the adjacent inverted trough-sections. It also supports the members. of the grids or armoring and, since it is substantially impervious, it protects the steel; grids from corrosion. In turn, the grid reenforces the concrete and takes a portion of the stresses to which the surface is subjected. when concrete with a grid or armoring embedded as in my preferred embodiment is utilized, the concrete will not crack and will remain in position indefinitely.

This statement is based on test installations made and subjected to very severe traillc conditions.

Many other types of fill may be utilized. As-

phalt or similar materials may be employed as asphalt may be employed as a fill. In such cases;

the concrete would be poured into the trough-sections and a mastic used to embed the grid. In using a combination fill, the concrete may be prepared in slabs and fitted into the troughs in pre-- formed condition, and the crevices around them filled with the mastic.

Referring now to Fig. 6, which shows diagrammatically a portion of a pan, it will be readily seen that the portion 21 of the trough-section above the neutral axis is a duplicate of the,

trough-section 22 below the neutral axis. The metal ofZ-the pan section is evenly distributed so that we have the same amount of metal to carry the tension and compression stresses. This is the ideal condition. Therefore in my invention the metal is used eiliciently.

In the well known 1' design of fioor structure, the steel is not evenly distributed and the same balance is not obtained as in the pan structure disclosed in this application. In the T design,

the T beams are disposed side-by-side forming a.

deck for receiving the fill.

The following table gives comparative weights 7 per square foot and stresses for the two constructions when designed for the same loading:-

Trough Pound: ads Steel floor-.- I). 9 l4. 1 Concrete-.. 30.0 25.0 Steel M0 3.0

Total weight- 50. 9 42. 1 Tensile stress 12, an 16. aoo Compressive stress 21, 900 16, am

The floor structure disclosed, as be evident from the foregoing table, is much lighter than floor structures heretofore utilized and permits the use of lighter frames and trusses, thus effecting a great saving in materials. Further, this type of floor structure may be more rapidly erected than the types now in general use.

Since numerous changes may be made in the above described structure and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. A bridge fioor comprising, in combination,

tary structure, and welds joining the bottom por tions of the crimped plates to the stringers to form the downwardly openingtrough sections of the crimped plates into boxed sections.

2. In a floor structure, in combination, beams,

metal plates disposed thereon and crimped into a plurality of alternately inverted substantially rectangular trough sections, a grid member super-imposed upon said trough sections, and welds joining said grid member to the upper sides of downwardly facing trough members to bond the said grid across the open portions of the up-.

I 1mm wardly opening troughsections to constitute the latter as boxed sections. v y 1 Q v 3. In a floor structure, in eombinatlombean s, metal plates disposed thereoniand-crlmped' into a plurality of alternately inverted substantially rectangular trough sections; a grid member su-- open trough sections secure against lateral de flection. I

' 4.1Ina Bridge noon. in names; a metal. plate crlmped lnto a plurallty .ot'substantiaily reotangular-troughzsections which are alternate inverted, a grid carried by the 'crlmped plate; welds joining the 'grld'to the upper members-o! I the trough sections 'tobox the upwardly open trough sections, and a flll 1or' the and the crimpedplate. the grid belng enibedded in the 1111 to torm a tread surface comprising the grid j

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