US1307031A - allbbight - Google Patents

Description

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a m m m 1 6 4 II w lllll T w m d w W Q k Patented June 17, 1919.

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. AL LBRIGHT CONCRETE CONSTRUCTION.

APPLICATION FILED MAR. 9. 1918 i l-"l I'- 1,307ZU3L 3 SHEETS-SHEET 3.

Patented Junem 1919.

E. F. ALLBRIGHT.

CONCRETE CONSTRUCTION.

APPLICATION FILED MAR. 9. 1918A w l l l l l l l l l flammap.

EDWIN F. ALLBRIGHT, 0F ATLANTIC, MASSACHUSETTS, ASSIGNOR TO ADAMSPONJD COMPANY, INC. OF'BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

CONCRETE CONSTRUCTION.

Specification of Letters Patent.

Patented June 1%, 191%.

To all whom it may concern:

Be it known that I, EDWIN F. ALLBRIGHT, a citizen of the United States, residing at Atlantic, county of Norfolk, and State of Massachusetts, have invented an Improvement in Concrete Constructions, of which the following description, in connection with the accompanying drawings, is a speclfication, like characters on the drawlngs representing like parts.

The invention hereinafter described relates to concrete construction and more particularly to slabs having domed or recessed panels.

Heretofore these slabs have been carried by a four-side support in the form of steel beams or concrete beams reinforced by steel. In some instances the beams are, wholly within and a part of the slab, and in other instances the beams project beneath the slab. This construction has been found to be objectionable for various reasons. Among others, the beams add to the amount of concrete and steel required, increase the weight of the slab, increase the bending moments of the slab, and add to the cost thereof. Also where steel beams are used, they divide the slab into separate panels with consequent loss of the desirable mutual strengthening.

effect of panels in a continuous slab.

One of the objects of the present invention is to provide a slab in which the necessity for beams extending from column to column is eliminated. As a result, a great saving both in concrete and steel is effected.

Another object of the invention is to provide solid concrete areas above the columns or supports roj ecting a substantial distance therefrom, and domed or recessed areas be tween said solid areas, the construction being such that the solid areas project toward one another with cantaliver effect and shorten the span of concrete therebetween.

And another object of the invention is to provide dropped panels beneath the solid concrete areas and above the capitals on the columns, thereby desirably distributing the support from the capitals to the solid areas and contributing to the eflicient cantaliver action thereof in sustaining the domed or recessed areas between said solid portions.

With the aforesaid and other objectsin view, the character of the invention will be best understood by reference to the following description of one good form thereof shown in the accompanying drawings, where1n:

Figure 1 is a perspective view looking toward the under side of a concrete floor slab embodying the invention supported on columns;

2 is a plan of a portion of the slab;

Fig. 3 is a vertical section through the slab taken on line 33 of Fig. 1;

4 on an enlarged scale is a vertical sectlon through two adjacent domes or recesses in the slab showing the forms in place for producing the same;

Fig. 5 is a perspective view of the type of form used to produce the domes or recesses in the slab;

Fig. 6 is a perspective view of a portion of the shoring for temporarily supporting the concrete;

Fig. 7 is a plan showing the arrangement of the shoring for supporting the dropped panel above one of the columns; and

Figs. 8 and 9 are views of details to be referred to.

Referring to the drawings, the constructlon shown therein as embodying the invention comprises columns 1 (Figs. 1 and 2) preferably of concrete and provided with flaring capitals 3 of circular form. The concrete slab 5 is mounted on the columns, and in the present instance of the invention, dropped panels 7 are provided between the capitals and the slab, formed integral therewith and project a substantial distance beyond the columns and capitals to distribute the support from the capitals to the slab.

The slab 5 comprises solid concrete panels or areas 9 above and integral with the dropped panels 7 and bays or areas 11, intermediate said solid areas and dropped panels, having domes or recesses 13 formed in and distributed throughout the areas 11. Each of these domes or recesses, in the present instance, is rectangular at its lower end, and the walls or ribs between adjacent domes or recesses slope upwardly, thereby producing a desirable arch effect. The walls or ribs preferably are relatively thin as compared with the areas of the recesses.

The construction is such that the solid concrete areas and the dropped panels project a suflicient distance from the columns and toward one another to produce a desir throughout through the walls able eantaliver effect and shorten the span of concrete between them without requiring steel or concrete beams to connect the same. Moreover, the domes or recesses distributed the concrete areas between the solid areas substantially diminish the weight of the area of the slab between the solid areas, and consequently, decrease the burden on the latter.

To further strengthen the construction, suitable reinforcing means may be provided for the slab, in the present instance, in the form of steel rods or members 17 extending or ribs 15 between the domes or recesses adjacent the lower faces thereo Other reinforcing rods or memhere 19 project through the walls between the domes or recesses extendin transversely to the rods 17, the latter, in tlie present instance, passing over and across the rods 19. The rods may have portions 21 inclined upward adjacent the juncture of the domed or recessed area of the slab with the solid area thereof to strengthen the same against shearing stresses. Also, the rods may have portions 23 extending through the solid areas adjacent the upper surface thereof. The construction and arrangement of the rods is such that they provide tension reinorcement for the domed or recessed area of the 'slab, and tension reinforcement for the upper portion of the solid areas of the slab.

To produce the domes or recesses in the slab, a suitable form may be provided. In the present instance, a form 25 is shown of steel or other suitable material preferably stringers, washers 3-8 equilateral, and having a flange 27 projecting outward from the base thereof. The forms 25 may be positioned with the flanges of the adjacent forms engaging one another, thereby automatically determining the width of the walls between adjacent domes or recesses. ,7

Suitable shoring may be provided for supporting the forms while the concrete is being filled in over and around the same to produce the slab, and during a sufficient period to allow the concrete to harden sufliciently. The shoring shown herein comprises posts 29 (Figs. 3 and 6) having opposed blocks or brackets 31 detachably secured thereto by bolts 32. These brackets support stringers 33, which also rest on stringers 34 detachably connected by bolts 34: to posts 29 adjacent the columns. Thestringers 33 may support transverse stringers 35 separated by suitable spacing blocks or caps 37 mounted on the upper ends of the posts. The flanges of the forms may rest on the stringers 35, a single stringer serving to support flanges of two adjacent rows of forms.

To help hold the forms in position on the (Fig. 8) may be placed on the corners of the flanges 0f the forms and be secured to the stringers by nails 38 projecting through holes in the washers and the spaces between adjacent corners, and thence into the stringer In some cases the span between the solid areas of the slab may be such that the standard forms used will not equally divide said span. To provide for such contingency, fillers 27 (Fig. 9) may be provided at the edges of the form flanges 27 to increase the width of the ribs or walls between the domes or recesses. Two stringers may be used to support the flanges of-adjacent forms when lers are used therebetween.

To produce the dropped panel, a sectional form 39 (Figs. 3 and resting on stringers 34 mounted on the osts 29 adjacent the columns. Suitable brackets 43 may be provided on said posts to contribute to the support of the forms 39.

The construction of the forms is such that simple shoring requiring a minimum amount of material may be employed to support the forms.

After the concrete has hardened somewhat, the bolts 32 and the blocks 31 may be removed from the posts 29 and the bolts 11 may he removed from the stringers 41. This will permit removal of all the stringers and the dropped panel forms 39 and leave merely central rows of posts with their caps supporting the central The other dome forms, removed with the stringers, are then available for use on other construction. The washers 38 over the form flanges and nailed to the stringers may assist in starting the forms from the concrete when the stringers are pulled down. As a consequence, a comparatively small number of forms will suffice to produce the construction, and only a small number need be transported from place to place and stored.

After the concrete has hardened sufliciently, the central posts and caps may be removed together with the forms above the same, thereby leaving a slab construction having concrete domes or recesses therein as shown in Fig. 1.

The bending moments of a slab carried by ams arranged to give a four-side support are materially greater than the bending moments of a girderless or continuous flat slab supported on columns. As a consequence, slabs having the four-side support must be formed of more concrete and be provided with more steel reinforcement than the continuous flat slab. Since the slab of the present invention can be constructed in accordance with the bending moments for a continuous slab, there is a great saving both in concrete and the steel reinforcement required therefor.

Since the concreteon the lower side of the neutral plane, between the portions of the concrete which experience compression and tension stresses, is weak in tension, it is relarows of dome forms.

tively ineflicient as compared to the concrete above said plane in contributing strength to the slab. By the domes or recesses described, large portions of the concrete beneath said plane are eliminated, thereby reducing the weight of the concrete in the spans between the cantaliver portions of the slab and the amount and weight of steel necessary to furnish the requisite tension reinforcement therefor.

It will be noted that no beams are required in the spans between the columns, but that in place thereof a light slab is employed which is supported by the solid cantaliver areas of the concrete above the columns.

It will be understood that the invention is not limited to the specific embodiment shown, but that various deviations may be made therefrom without departing from the spirit and scope of the appended claim.

What is claimed is 1- In concrete construction, the combination of columns, solid panels resting on said columns and projecting substantial distances beyond said columns with cantaliver effect, bays between said solid panels, each bay having a solid upper surface portion and series of transversely extending ribs depending therefrom with deep domes or recesses be tween said ribs open at the under side of the slab, said domes or recesses being distributed throughout the bays to all of the margins of the solid panels, and transversely extending tension reinforcing members inclosed in said concrete ribs, said solid panels and bays constituting an integral concrete slab extending continuously across said columns.

In testimony whereof, I have signed my name to this specification.

EDWIN F. ALLBRIGHT.

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