US1989254A

US1989254A - Floor construction

Info

Publication number: US1989254A
Application number: US331921A
Authority: US
Inventors: Donald D Whitacre
Original assignee: WHITACRE ENGINEERING Co
Current assignee: WHITACRE ENGINEERING Co
Priority date: 1929-01-11
Filing date: 1929-01-11
Publication date: 1935-01-29
Anticipated expiration: 1952-01-29

Description

Jan. 29, 1935. w Ac 1,989,254

FLOOR CONSTRUCTION Original Filed Jan. 11, 1929 2 Sheets-Sheet l Jan. 29, 1935. D w c 1389,2554

FLOOR CONSTRUCTION Original Filed Jan. 11, 1929 2 Sheets-Sheet 2 IIIIIIIII'IIA Patented Jan. 29 1935 rtoon ooNs'rnUo'noN Donald D. Whitacre, Waynesburg, Ohio, assignor eering Company, Ohicago, 11L, a corporation of Ohio Application January 11,1929, Serial No. 831,921 Renewed December 7, 1932 9 Claims. (01. 72-66) to The Whitacre En This invention relates to hollowtile and reinforced concrete floor construction and more particularly to the arrangement of the respective elements and the proportions of the tile blocks.

I have discovered in the design of floor slabs of the "one way" type, that is, where joists are parallel and non-intersecting, that there are certain limiting factors which have always existed but which have heretofore been regarded as elements which have led to unnecessary waste or extravagance in floor construction. Thus the reinforced concrete joists. including the integral concrete slab parts of the floor, have been designed to take the maximum load throughout their length, whereas the maximum load for a givenjoist may be greatest in shear at its ends and needlessly strong to oppose bending moments in its middle. Furthermore in designing joists, it has been found necessary to make the joists at least four inches wide to facilitate the placing of reinforcing bars, and such joists if spaced apart by the usual tile blocks of 12 inch width, may very well be too numerous in a given floor and unnecessarily wasteful of concrete. This waste has often been accepted on the excuse that while the body of the joist was overdesigned, the ends needed the strength to carry shear loads. There is also in the bottom of each joist a certain idle amount of concrete disposed below the reinforcing bars. I propose to pour the joists at least.

on twenty inch centers with blocks at least sixteen inches wide between, and thus save 20% of the loss in concrete. which lies idle under the bars.

I am familiar with designs disclosed in prior art wherein greater spacing of joists in one way floors has been effected by using tile blocks of greater length than twelve inches and spacing these blocks so that their open ends are exposed to the joists. This arrangement reduces the number of necessary joists but is wasteful of concrete because of the indeterminate amount of concrete which flows into the voided ends of the tile blocks. While the extra concrete flowing into the ends of the tile blocks may be useful, particularly at theends of the joists in incorporating the tile into the floor to aid in carrying shear loads and/or negative moments, it is either unnecessary at the ends or wasteful in the middle of the slab.

It is therefore among the objects of my invention to provide a'floor which willv develop the greatest strength of all of the elements therein; which will obviate waste: and which may be easily and cheaply laid and poured. Another object is to provide a floor wherein tile blocks of like size diflerent relative cross-sectional areas of tile and concrete at various places in the floor depending on and appropriate to the load at such places. A further object is to provide a floor including tile blocks of great width and to lay these blocks between joists with the voids in the blocks extending parallel with the joists so that concrete is excluded from the voids. A still further object is to provide blocks between .joists whose width is great enough to reduce the total numberof joists to permit the more emcient use of concrete in deeper and less numerous joists. A still further object is to provide an all tile ceiling.

A particular object is to provide a floor having joists spaced at least twenty inches between centers with hollow tile blocks at least sixteen inches wide disposed between joists. Another object is to provide a floor wherein the tile blocks are at least four times the width of the joists. A further object is to provide blocks which are shorter than they are long whereby certain blocks may be laid with their voids normal to the joists and will then have a lateral dimension less than four times the width of the joist and preferable one and one-half times the width of the joist. Another object is to provide a floor having tile blocks of like size and shape which are laid with their voids parallel to the joists to give joists of a certain width and which can be turned with their voids normal to the joists to give joists of substantially twice that width.

Other objects will appear from the following description of a preferred form of my invention.- reference being had to the accompanying drawright portion a finished floor with the top slab poured; Fig. 2 is an isometric view of a'portion of a row of tile blocks as positioned in my slab; Fig. 3 is a section taken through the tile part of the slab parallel to the joist including a girder between slabs; Fig. 4 is a section taken through the slab at right angles to the joists and in the middle part thereof; Fig. 5 is a section taken at right angles thereof.

to the joists adjacent the ends flush with the top of the girder.

Referring to the drawings, my slab comprises essentially concrete joists 1 which are formed integrally with girders 2 and extend at right angles thereto. Laid within the joists are the usual reinforcing rods 3 which through the body of the floor lie near the bottom of the joists and may be brought upwardly as partially indicated in Fig. 5 near the ends. The concrete part of the slab may also comprise a top layer 4 which lies Hollow tile blocks preferably all of like size and shape, are incorporated in the floor and lie between joists under the top slab 4. Somt tiles 11 are laid under the joists to provide an all tile ceilins.

Referring particularly to Fig. 2, I prefer that the tile blocks 10 be laid in parallel rows with the voids of the tile extending parallel with the joists so that the blocks space the joists apart. At

the end of each row of blocks and abutting the girders 2, I prefer that one of the blocks be turned to have its voids extend normal to the joists. The blocks 10 are preferablyat least 16 inches wide and 12 inches long so that the block at the end of the row has a smaller lateral dimension than the blocks in the body of the row.

Thus as illustrated in Figs. 4 and 5, the blocks in the body of the row are substantially four times as wide as the joists, which in the illustrated instance are 4 inches wide and are arranged on 20 inch centers. I prefer that these blocks be cut in twelve inch lengths so that the blocks at the ends of a row, as illustrated in Fig.

5, extend 12 inches between joists, thus permit-- ting the joists to be 8 inches wide at the ends and 4 inches wide throughout the remainder of their length. Furthermore, the end blocks receive lugs of concrete 15 in their voided ends, which not only secure the blocks but also incorporate blocks into the part of the slab adjacent the girder where the load and shear is high and where the tile takes part of the load of the negative bending moments. Thus the joists are poured on inch centers and the body of the joists are 4 inches wide while the ends of the joists are substantially twice as wide and have in addition the lugs of concrete 15 which also incorporate at least a portion of the webs and shells of the laterally disposed end blocks.

In laying the floor, I am able to use an open form work comprising essentially wooden members 20 lying below the joists which support'the soilit tiles 11 and support the edges of the main tiles 10. Thus the tile blocks 10 constitute a great part of the form work and obviate the necessity of a closed or complete form with the result and benefit of economy. After the tiles are set on the appropriate form work, the reinforcing rods are laid in the spaces between the blocks 10 and the concrete is poured in the usual manner. I illustrate the blocks 10 being preferably about 5 inches in depth and it will be appreciated that varying depths may be used according to the loads.

The soflit tiles 11 may preferably be of a length equal to the length of the blocks 10. In the ends of the joists and adjacent the laterally disposed blocks, two soflit tile are laid between such blocks and a third tile having substantially one-third broken away is laid crosswise of the joists as at 12.

In designing my floor, I start with the premise that the concrete may be used more efliciently in deep and narrow joists and I find that a minimum effective width of joist, from the point of view of placing the reinforcing rods, is about 4 inches. with joists of this width, I determine the depth necessary to develop the bending moments for the desired loads in the middle of the floor, reckoning that the joists be laid on 20 inch centers. The fact that I use tile blocks which are 16 inches wide reduces the number of joists in the floor and permits me to develop the maximum strength of the concrete poured into each of the joists. The greater spacing of joists may cause the floor to be weak in shear adjacent the girder and at these ends I take one of the tile 10 as mentioned, at the end of each row and turn it so that it displaces only 12 inches between joists and permits the joists to be eight inches wide instead of 4 inches wide at their ends. Thus the resistence to shear is more than twice as great at the ends of the joists as in the middle because, as mentioned above, the end blocks receive lugs of concrete in their voided ends from the joists which incorporate at least parts of the tile in the body of the floor which takes the shear load. The blocks thus being locked with the intruding lugs of concrete also aid in withstanding the negative bending moments so that the strength of the tile at this point is added to the strength of the concrete.

- While I have illustrated and described a preferred form of my invention, I do not care to be limited in this or any manner other than by the claims appended hereto.

I claim:

1. In a one-way reinforced concrete and tile floor, the combination of hollow tile blocks of greater width than length laid end to end in rows between joists with their voids extending parallel to the joists and at least one tile block at the end at each row between the ends of adjacent joists arranged with its voids extending at right angles to the joists and receiving lugs of concrete from the joists whereby the ends of the joists are of greater width than the bodies thereof and whereby the end blocks are incorporated with the jo to carry loads in bending and shear.

2. In a one-way reinforced concrete and tile floor, the combination of hollow tile blocks with longitudinally extending voids having greater width than length and being disposed between joists with their voids extending parallel thereto, at least one of said tile blocks between the ends of adjacent joists being arranged with its'voids extending at right angles to the joists whereby the ends of the joists are of greater width than the bodies thereof.

3. A floor comprising hollow tile blocks laid in rows defining channels between the rows into which concrete joists may be poured, all of said blocks being sixteen inches wide and twelve inches long andlaid end to end throughout the body of each row to present their side walls to the joists, each row having at its ends blocks which are turned to present their voided ends to the joists so that these end blocks measure but twelve inches between joists and receive lugs of concrete from the joists in their voided ends.

4. A concrete and tile floor comprising rows of hollow tile blocks arranged between parallel concrete joists wherein the hollow tile blocks are at least sixteen inches in width and at least four times the width of the joists in the mid portions thereof, said hollow tile blocks being arranged end to end to present their sides to the joists, said hollow tile blocks being shorter than sixteen inches and each row of tile blocks having at its endat least one block turned with its shorter dimension measurable between joists whereby the joists are wider at the ends than they are throughout their mid portions.

5. A hollow tile and concrete floor comprising parallel rows of hollow tile blocks between which concrete joists are poured, the hollow tile blocks being at least sixteen inches wide and twelve inches long and laid end to end in each row and being substantially four times as wide as the adjacent joists, certain of the blocks particularly at the ends of each row being turned and laid with their voids at right angles to the voids of the blocks in the body of the row and displacing but twelve inches between joists and measuring no more than one and one-half times the width of the adjacent joist.

6. A floor comprising parallel reinforced concrete joists having rows of hollow tile blocks bonded between them, said joists being at least twice as wide at their ends as throughout their mid portion, tile blocks between the mid portions of the joists being at least sixteen inches wide and laid with their voids extending parallel to the joists, and the tile blocks at the ends of the joists displacing no more than three quarters of the width of the blocks in the body of the row of tile.

presenting their sides to the joists, said floor also having blocks of lesser width between the ends of adjacent joists whereby the lateral displacement of tile between the ends of the joists is materially less than that between the main portions of the joists.

8. A one-way reinforced concrete and tile floor having relatively wide hollow tile blocks disposed between joists with their voids extending parallel to the joists, said tile blocks abutting end to end and presenting their sides to the joists, said floor also having blocks of lesser width between the ends of adjacent joists whereby the lateral displacement of tile between the ends of the joists is materially less than that between the main portions of the joists. v

'9. A one-way reinforced concrete and tile floor having parallel spaced apart reinforced concrete joists, and parallel rows of voided tile blocks laid end to'end and contacting with each other and bonded between said joists, said tile blocks having their voids extending parallel to the joist and presenting their side walls to the joists, said blocks being at least sixteen inches in width, and means comprising blocks of less width than said firstmentioned tile blocks associated with the blocks at the ends of the rows for closing the exposed voided end and excluding concrete therefrom and for increasing the width of the joists at the end thereof.

DONALD D. WHI'I'ACRE.