US721982A - Concrete arch. - Google Patents

Description

PATENTED MAR. 3,1903; G. B. WAITE. 'CONCRETE ARCH.

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UNITED STATES PATENT OEEICE.

GUY BENNETT WAITE, OF HOBOIIEN, NEW JERSEY.

CONCRETE ARCH.

SPECIFICATION forming part of Letters Patent No. 721,982, dated March 3, 1903.

Application tiled April 19, 1902. Serial No. 103,766. (No model.)

T0 @ZZ whom t may concern..-

Be it known that I, GUY BENNETT WAITE,

a citizen of the United States, residing at Hoboken, New Jersey, have invented certain new and useful Improvements in Fireproof Floor-Arches, of which the following is a specification.

My invention relates to improvements in the construction of concrete floor-arches having steel members as a component part of the construction.

I have discovered that small light thin steel channels entirely embedded in the concrete below the neutral axis, with the whole construction resting upon and solidly built between rigid supports, take suiiicient hold on the concrete to not only make the steel act as a tension member after the concrete is thor# oughly hardened, but such steel sections are of great service in4 holding up the concrete when the latter is only partially hardened.

A ireproof oor construction embodying my invention in several forms is illustrated in the accompanying drawings, wherein- Figure l is a top view showing floor-beams and steel arch-channels running at right angles to them. Fig. 2 is a longitudinal sectional view of the construction shown in Fig. l and showing the channels as run over the tops of the floor-beams and dropped down into the concrete between said floor-beams.

Fig'. 3 is a similarsectional view on the line A A of Fig. 1, illustrating a construction wherein the channels are hung in suspenders from the tops of the floor-beams. Fig. 4 is a sectional view of a concrete-arch construction where the concrete and the steel channels rest on top of the lower flanges of the Hoor-beams. Fig. 5 is a cross-sectional view ofthe construction shown in Fig. 2. Fig. 6 is a cross-sectional view of the construction shown in Fig. 3. Fig. 7 is an enlarged crosssectional view of the construction shown in Fig. 4, and Figs. S and 9 are detail views showing the Suspenders for holding the steel channels in position for the construction illustrated in Figs. 3 and 6.

Referring to the drawings, the letter I designates ordinary steel girders or floor-beams of the usual I-beam pattern for supporting the Hoor-arches.

C designates the concrete filling extending between adjacent floor-beams. In this concrete filling I embed at suitable intervals a series of light thin steel channels, these channels lying in a direction at right angles to the floor-beams and longitudinally of the concrete arches formed between the hoor-beams, and one salient, valuable, and novel feature of my invention resides in making these channels low or thin in vertical dimensions relatively to the total thickness or height of the concrete filling, so that thechannels do not have the effect of widely separating the volumes lying between them'v and cutting the arch up into slices, as it were, as has heretofore been done in the case of insertions of height a nearly equal to the thickness of the concrete itself. Another novel and valuable feature of my invention resides in the location of these channels in the tension zone of the arch, whereby they become and act as tension members of Va truss and of which the superposed body of concrete constitutes the compression member, and being so located to serve as tension members purely they can obviously be made of very light and thin steel consistently with their highest efficiency for their intended purpose. While it is of the essence of my invention that these steel reinforcing-channels be located relatively to the body of concrete, as before described, yet it is obvious that for the purposes of construction they may be supported in a variety of ways during the filling in of the concrete therearound. Fox-instance, in Figs. 2 and 5 I have shown them as run over the tops of the floor-beams and dropped down into the concrete.' In Figs. 3 and 6 I have shown them as suspended in position by means of wire Suspenders E, hung over the tops of the floor-beams and carrying the ends of the channels. In Figs. 4 and 7l I have shown the channels as resting at their ends upon the lower ianges of the floor-beams. In all of these constructions it will be understood that the means shown for supporting the channels are not intended to constitute any part of the strength-giving element or feature of the ioor construction, but are merely designed to hold the channels in proper position, as it were, during the filling in of the concrete, both the concrete filling and the channels nding their ultimate real ICO support on the lower flanges of the floor-beams constituting the base-supports of the arch. It will be understood that in the case of the construction illustrated in Figs. 4E and 7. the concrete flat arch C, with the embedded channels, is as much a tloor construction as either ot' the constructions shown in Figs. 2 and 3, since any suitable ller will be interposed above the concrete up to the level of the tops of the Hoor-beams.

When the entire construction is built on top of supports and is tightly embedded between rigid abutments, the construction has three distinct elements of strength-first, the strength of the channels, stillened with the concrete engaged about it, acting as an independent beam; second,the concrete (strengthened with the channels) wedged in between abutments acts like a real arch, the upper part of the concrete being the crown of the arch; third, the concrete and the steel channels acting together as an independent beam, the concrete taking the compressive stresses and the channels taking the tensile stresses of the steel concrete beam.

I have found that the chanuel'section where not high enough to weaken the concrete by cutting it into sections is capable of acting with the concrete in the various ways above mentioned, and the combination when used in the manner described is capable of forming arches of phenomenal strength. It will be seen that a load placed midway between the beams tends to deflect the mass downward. This not only puts the channels in tension, but also tends to similarly deflect the channels. To resist such deflection, the channel form is greatly superior to a round rod or wire or a ilat bar of equal cross-sectional area, so that the channel, supported at its ends by the flanges of the floor-beam through the vertical legs of the concrete, lends a valuable direct resistance to vertical deflection as well as a tensile resistance in the concrete mass.

I am aware that it is old to embed steel beams, rods, wire-netting, and the like in the concrete or cement of floor and ceiling constructions, and I make no claim, broadly, to the use of such steel reinforcing devices; but, so far as I am aware, such steel beams as hitherto employed have been so located as to virtually cut the concrete vertically into slices or sections, and thus produce an element of weakness in the construction greater than their supposed reinforcing effect, while Wires, netting, and the like similarly embedded have been found unsatisfactory by reason of their tendency to stretch and yield. Both of these difficulties I believe I have overcome through the employment of comparatively light low thin steel channel-beams wholly embedded in the concrete mass and located below the neutral axis and within the tension zone of the arch, and, so far as I am aware, I am the first to employ such reinforcing devices in such a relation to the concrete mass.

I claiml. In a concrete-floor support the combination with the concrete, of small light steel channels wholly embedded in the lower zone thereof to reinforce the tensile resistance in said zone.

2. In a concrete-floor support, the combination with the horizontal concrete mass of small light steel channels wholly embedded in the tension region of said mass, the whole supported upon the lower flanges of the beams.

3. The combination with small light steel channels supported during construction by suspension from the top of the beams, of a horizontal concrete mass cast upon and about said channels and embedding them wholly in its tensional portion, and, adjacent to the beams, extended downward to the lower flanges thereof.

Signed at the city of New York,in the county of New York and State of New York, this 18th day of April, A. D. 1902.

GUY BENNETT WAITE.

Witnesses:

JOHN H. HANAN, PHILIP J. MCKINLEY.

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