US3388452A - Method for ceiling construction - Google Patents

Description

June 18, 1968 w. H. CONNOLLY 3,388,452

METHOD FOR CEILING CONSTRUCTION Filed Feb. 8. 1966 5 Sheets-Sheet l June 18, 1968 Filed Feb. a, 1966 w. H. CONNOLLY 3,388,452

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United States Patent METHOD FOR CEILING CONSTRUCTION William Henry Connolly, 22 Wagonwheel Road,

Sudbury, Mass. 01776 Continuation-impart of application Ser. No. 425,197,

Jan. 13, 1965. This application Feb. 8, 1966, Ser. No. 525,924

4 Claims. (Cl. 29-428) ABSTRACT OF THE DISCLOSURE Preparing for construction of one-way ribbed concrete ceilings by using a single collection of rib forming domes for substantially any span length, the collection having domes of at least three lengths between five and nine feet and differing by one foot, a combination of domes being chosen for each ceiling and assembled on temporary supporting framework in parallel rows, the end-to-end bodies of the domes being spaced to form bridging ribs running transverse to carrying ribs, the combinations being chosen so that whenever domes of a single length cannot span the ceiling domes of exactly tw lengths differing by one foot are used.

This application is a continuation-in-part of application Ser. No. 425,197, filed J an. 13, 1965, and now abancloned.

This invention relates to ribbed concrete ceilings of the type built over removable form molds, and provides an improved method of preparing, with a system of elongated domes, for the construction of such ceilings.

Ribbed concrete ceilings suitable to be left exposed are most commonly constructed with the aid of a large number of two or three foot square domes, using the columnsupported two-way structure having equally spaced carrying ribs in both directions. Often, however, architects prefer to use a one-way structure, with carrying ribs running along the ceiling span and supported at their ends by beams or walls. Bridging ribs running transverse to the span are usually employed to provide transverse stillness. In such cases special elongated forms (known in the trade as longforrns) are employed which must, in order to give a concrete finish suitable for exposed use, be fabricated to correspond to a given ceiling span length and bridging rib arrangement, thereby incurring a substantial investment in special length form molds, particularly when a single building is to contain several ceilings with different spans. Usually the expense of custom form fabrication limits the architect to locating the bridging ribs at the third or midpoint of the span. Thus, while the cost of a two-way dome system can be amortized over an indefinitely large number of ceilings, as yet no way has been found to build an exposed one-way ceiling with a form molding system of suflicient reuse potential to avoid the necessity of allocating at least the major portion of form cost to a single ceiling. Such technique-s as adjustable elongated forms have been suggested and have failedthey do not produce a concrete finish of the desired high quality.

One object of the invention is to provide a uniform method of preparing for the construction of a large number of one-way ribbed concrete ceilings of varying span Patented June 18, 1968 "ice lengths, with a single system of re-usable elongated mold ing domes.

Other objects are to provide a method, as described above, which is easily performed, at a minimum cost (including an allocated portion of dome cost, as well as the cost of dome installation labor), and in which the finished structure of each ceiling has an appearance of maximum smoothness, uniformity and apparent symmetry, suitable to be left exposed.

Another object is to provide a method, as described above, which can be employed with a variety of bridging rib arrangements in a given overall ceiling span, without incurring any additional expense.

Further objects and advantages of the invention will become apparent upon the detailed description of the preferred embodiment thereof, including the drawings, in which: a

FIG. 1 is a perspective view of two domes, 6 and 7 feet long, used in the method of the invention;

FIGS. 2a and 2b show a chart illustrating the manner in which dome lengths .are combined, wherein dome lengths are indicated by the numerals below the oblongs, and dome row length-s at the left, with asymmetric rows being denoted by oblique hatching, symmetric rows using one dome length by vertical hatching, and symmetric rows using two dome lengths by the absence of hatching;

FIG. 3 is a vertical section through a ceiling in which a nineteen foot dome row is used;

FIG. 4 is a vertical section through a ceiling in which a twenty-six foot dome row is used;

FIG. 5 is a plan view of the ceiling of FIG. 4;

FIG. 6 is a reflected ceiling plan illustrating combinations of special dome layouts where an overall ceiling span is subdivided into various room size ceilings, dome lengths being indicated by numerals within the oblongs; and

FIG. 7 is a vertical section through a bridging rib and partition shown in FIG. 6.

Referring to the drawings, typical domes employed in the invention are shown in FIG. 1, and each comprises a generally oblong top portion 10, integral end and side portions 12 and 14 extending downwardly from portion 10 and tapering slightly outwardly, portions 12 and 14 terminating in a common plane parallel to top portion End and side flanges 16 and 17 extend in that common plane outwardly from portions 12 and l irespectively.

In its broadest form the invention provides a system of domes having at least two different dome lengths including two predetermined lengths between 5 and 9 feet differing from each other by one or two feet. If only two lengths are used, 6 and 7, 7 and 8, or 6- and 8 feet are the preferred combinations. Additional lengths may be added, each differing from one of the two basic lengths by /2 or 1 foot, but the total number of different lengths should not substantially exceed three if all the advantages of the invention are to be realized.

In the preferred embodiment described herein, in which the number of different dome lengths and the number of domes used for a given ceiling are minimized, while the variety of ceilings that can be constructed is maximized, a dome system is provided with dome lengths of 6, 7 and 8 feet, taken between the outer edges of end flanges l6, and in standard widths of 25" or 36", taken between the outer edges of side flanges 17. Flange 16 is 1 /2" wide and flange 17 is 2 /2 or 3 wide. These 6, 7 and 8 foot domes are then combined according to a formula illustrated in FIGS. 2a and 2b to prepare for the construction of ceilings of almost any desired span length. Because the same dome system is used, in different combinations, in a wide variety of ceilings in the same or different buildings, almost unlimited reuse of the domes is possible, and their cost may therefore be allocated over many jobs.

More particularly, to prepare for the construction of a given ceiling, a temporary supporting framework (FIG. 3) is erected, including 4" x 4" timber vertical shores 2t), 4" x 6" stringers 22 running transverse to the ceiling span along the tops of shores 20, 2" x 8" soflit boards 24 supported by the stringers, and beam forms 26 at the ends of the ceiling span. The spacing of the shores and stringers is not critical, but the sotfits must be spaced less than the width of the domes, in order to support them. A combination of domes is then chosen to correspond to the dimensions of the ceiling, the domes to be arranged on top of the soffits in flange-abutting end to end and side to side orientation, with the length of the domes along the span, as shown in FIGS. 3-5. Standard techniques are then used to complete the ceiling, including the placement of reinforcing rods, conduits and the like, pouring of concrete, and ultimate removal of the domes with the aid of air holes 30.

By appropriately assembling various combinations of domes, a dome row can be prepared for any desired multiple of one foot over 11, save only 17, up to at least 60, as shown in the chart of FIGS. 2a and 2b. Surprisingly, it has been found that not more than two different dome lengths are required in any span and that these two need not differ in length by more than one foot, that is, 6 and 7 foot domes in combination or 7 and 8 foot. In each case the combination is chosen and arranged generally according to the criteria of minimizing the number of domes per row, and maximizing symmetry of domes (and hence of bridging ribs) about the transverse (to the span) center line of the ceiling. In only six cases is an asymmetrical arrangement necessary. Even here when viewed from inside a finished building, usually from below looking up at a perspective angle, the asymmetry will be difficult to detect because of the minimal one foot difference in dome lengths involved.

Those bridging ribs that remain when the method of the invention is followed are, by virtue of the 1 /2" end flanges, substantially narrower than the longitudinal carrying ribs, which fact serves to visually minimize their asymmetric arrangement when 13, 15, 25, 27, 29 or 41 foot dome rows are employed.

FIG. 4 illustrates the method of the invention in connection with a 27 foot span ceiling (taken from beam center to beam center). Two 7 and two 6 foot domes are arranged symmetnically about the transverse centerline of the ceiling to form a 26 foot dome row. A slight spacing remains between the free end flanges 16 of the endmost domes and the beam forms 26 to facilitate removal of the domes after the concrete is set. A 19 foot dome row, comprising two 7 foot and one 6 foot dome is used for the 20 foot span of FIG. 3.

The domes will normally be made of steel, although other materials such as fiberglass, etc. may be used.

FIGS. 6, 7 illustrate the advantages of the invention when architectural requirements dictate the subdivision of an overall ceiling span into rooms and corridors having individual ceilings of various sizes. In such cases, it is de sirable that the transverse partitions dividing rooms should fall along bridging ribs, which ribs then act as partition closure ribs allowing the partition construction to finish flush with the ceiling and providing a continuous sound barrier between adjacent rooms. As shown in FIG. 6, many combinations of rooms and corridors can be realized within a given overall span, a 30 foot overall dome row being used for illustration. In some of these arrangements, standard 2 foot square domes used in two-way construction are combined with elongated domes, to provide narrow width utility spaces along the sides of rooms or corridors. In each arrangement of FIG. 6 partition 32 is located flush with a partition closure rib 34, as best shown in FIG. 7. Bridging ribs not acting as partition closure ribs are shown in FIG. 6 at 36, and carrying ribs at 38. Of course, in these cases where the overall dome row is to be subdivided with partitions, the earlier mentioned criterion of maximizing dome symmetry should be applied, to the extent possible, separately to the dome sub-rows spanning the individual ceilings. Such flexibility in locating bridging ribs to act as partition closure ribs is not feasible with long-form construction, since, as mentioned earlier, the bridging rib must necessarily be held to the mid or third points of the span throughout for fabrication economy. Thus, it is often necessary to extend partitions up into the space between carrying ribs, a costly operation and difficult to do well.

Bridging ribs should be spaced apart by an integral multiple of one half foot (center line to center line) and preferably by an integral multiple of one foot. When the flanged domes of the preferred embodiment are employed in abutting end-to-end orientation, such spacing will require the domes themselves to be of a length (taken between the outer edges of the end flanges) equal to an integral multiple of one half foot (and preferably an integral multiple of one foot). More generally, however, the appropriate domes for a dome system to be used to produce properly spaced bridging ribs having a predetermined width, can be defined in terms of the effective dome body length L (FIG. 1) taken along the dome side portion without including any flanges or the like that may be present. The domes are then constructed with effective dome body lengths each equal to an integral multiple of one half foot (and preferably an integral multiple of one foot) minus the predetermined bridging rib width. In the preferred embodiment illustrated, the effective dome body length is taken between the inner edges of the end flanges. While measures have been defined in terms of English units, it is apparent that the invention has analogous forms in the metric system using a 30 cm. or similar module in place of one foot.

Variations within the scope and spirit of the invention will occur to those skilled in the art.

What is claimed is: 1. A method of preparing for the construction of oneway ribbed concrete ceilings of substantially any span length, said ceilings having elongated recesses defined between parallel carrying ribs and transverse bridging ribs, comprising the steps of providing a single collection of rib forming domes for use in all of said ceilings, said domes each having a body including a generally oblong top portion and integral side portions extending generally downwardly from said top portion, said collection having domes of at least three different predetermined effective body lengths differing by one foot, all of said predetermined lengths being between five feet minus a predetermined allowance for the width of a bridging rib and nine feet minus said allowance, inclusive,

providing a combination of said domes corresponding to each of said ceilings, and

assembling each said combination of domes on a temporary supporting framework in end-to-end and sideto-side orientation so that end-to-end rows of said domes will run in parallel along said ceiling, the bodies of said domes being spaced end-to-end a distance equal to the width of a bridging rib,

said combinations corresponding to ceilings which require a dome row length which is not an integral multiple of one of said dome body lengths plus said allowance having domes of exactly two different lengths differing by one foot.

5 6 2. The method of claim 1 wherein ecah of said domes References Cited has integral end and side portions extending generally UNITED STATES PATENTS downwardly from said top portion and terminating at a common plane parallel to said top portion, and end and i z 28 3; side flanges extending in said plane outwardly respectively 5 31513l4 10/1964 255; 31 X from said end and side portions.

3. The method of claim 2 wherein said end flanges are FGREIGN PATENTS substantially narrower than said side flanges. 704 541 2 19 54 Great Britain 4. The method of claim 1 wherein said three predeter- 309 990 12 193 Franw mined lengths are respectively six, seven, and eight feet 10 minus said allowance. JAMES L. JONES, JR., Primary Examiner.

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