US1974708A - Fireproof floor construction - Google Patents

Description

1934.. E. FIORDELJSI 1,974,708

" FIREPROOF FLOOR CONSTRUCTION Filed Sept. 6, 1930 6 Sheets-Sheet 1 Sept. 25, 1934. E. FIORDELISI 1,974,703

FIREPROOF FLOOR CONSTRUCTION I Filed Sept. '6. 1930 6 Sheets-Sheet 3.

P E. FIORDELISI 1,974,708

FIREPROOF FLOOR CONSTRUCTION Filed Sept. 6. 1930 6 Sheets-Sheet 4 Sept. 25, 1934. E. FIORDELISI 1,974,708

I FIREPROOF FLOOR CONSTRUCTION Filed Sept. 6. 1930 6 Sheets-Sheet 5 Spt. 25, 1934. FIORbELlSI I 974,708

FIREPROOF FLOOR CONSTRUCTION Filed Sept. 6. 1950 QSheets-Sheet e 2 J g M W Patented Sept. 25, 1934 v UNITED STATES PATENT OFFICE maizraoor rL'ooR CONSTRUCT ON Ernesto Fiordelisi, New York, N. Y., assignor to Construction Materials Development Corporation, New York, N. Y., a corporation Application September 6, 1930, Serial No. 480,245

13 Claims. (01. 72-66) This invention relates to building constructions, and more particularly to precast blocks formed of concrete or similar material which are incorporated in position in building construc- 5 tions to constitute arches of self supporting character with cooperating precast blocks for forming desirable adjuncts to the arches.

For sometime past many of the buildings constructed have involved the pouring of concrete .10 and the like intoforms to permit the setting thereof in such relation to the remaining building construction that it became permanently associated therewith and constituted a part of the complete building. When a building is constructed in this manner, it is necessary to have numerous forms for the concrete being poured, which forms must be maintained in theoperative position until the poured mixture has set sufiiciently to be self sustaining. The delay encountered in such construction is very objectionable, not only because of the period of time which the forms must be maintained in position before removal for further operation, but additionally because of the delay necessary in the completion of the building. I

In the construction of a building by the pouring of cement insitu the cement body must be of necessity very heavy because 'of the normal aggregation employed in the walls or flooring, as the case maybe, even when a comparatively thin construction is produced-v The normal construction of floors is comparatively thin with respect to the steel framework composed of girders and connecting beams, and due to the size of the beams normally employed the thickness of the concrete poured in situ only, extends over a relative short portion of each beam, which results in the lower portion, of each beam being visible from the next lower floor level. "It has been customary to applyia covering of concrete or plaster over the portions of the beams which extend or project downwardly from the ceiling, but even then the existence of the obstructions across the ceiling is objectionable from boththe standpoints of fire hazard and of unsightliness.

The building codes of some localities now require that the ceilings be substantiallyunobstructed because of the fire hazard involved by the ordinary 1 construction. Attempts have been made to overcome the formation of the unobstructed ceiling by the rearrangement of the forms and. the pouring of the concrete, in situ, but the resultant thickness of the concrete is extremely objectionable and the forms must necessarily remain in place fora longer period during the setting of the concrete, and too the weight of the structure is materially increased.

The present invention contemplates the construction of buildings wherein the above noted objections are overcome. It is an object of the present invention to effect the formation of floors of a reduced weight which present unobstructed ceilings, and which may be constructed in a period of time greatly reduced from the time normally consumed in those constructions presenting the obstructed ceiling.

The invention further contemplates the employment of an arch construction in combine:- tion with the steel framework of buildings wherein precast blocks are employed and the use of extensive concrete forms is eliminated.

It is a further object of the invention to provide a floor construction formed of a plurality of precast units certain of which maintain their individual identity even in use so that the strain of expansion of the units is independently transwith other types of blocks in theformation of the building so that a large variety of blocks is unnecessary and only a practical number are employed.

A further object of this invention is to provide an improveddevice of the character described which comprises precast blocks for flooring which result in a flat or plain lower ceiling, said blocks being supported on any suitable framework that is encased'therein'. The invention also contemplates as an advantage that the usual temporary forms or molds for concrete or the like, do not have to be built according to thepresent practice.

Another result of this construction is the elimination of labor formerly required inrplastering at the sides ofthe beams and in the formation of'the necessary corners. A further advantage of the arrangement mentioned, is the improved fire resisting quality be transferred to the I-beams are reduced, while the movement and removal of hot gas currents under the ceiling is rendered free.

Another object of this invention is toproduce thereof, since the areas over which heat might an improved structure of the nature set forth wherein the blocks referred to enclose the lower flanges of the I-beams, and are supported thereon, the blocks forming arches whose lateral stresses are assumed by the webs of the aforementioned beams, the lower surfaces of these blocks providing the ceiling;

A further object of the invention is the provision of an improved fireproof floor of the type specified wherein certain of the blocks form skewbacks extending along the sides of the I-beam and the spanning blocks extend in integral formation from one skewback to another.

Still further objects of the invention reside in the hollow light character of the blocks wherein strength is combined with insulating and sound-proof quality; in thehigh degree of simplicity of the invention and the inexpensive form in which it may be practiced; in the preliminary supporting arrangement of the blocks, and in the method pursued and described herein.

Other objects will in part be evident and in part pointed out hereinafter.

The advantages of the invention as here out-'- lined are best realized when all of its features and instrumentalities are combined in one and the same structure, but, useful devices may be produced embodying less than the whole.

It will be obvious to those skilled in the art to which the invention appertains, that the same may be incorporated in several different constructions. The accompanying drawings, therefore, are submitted merely as showing the preferred 'exemplification of the invention.

In the drawings, in which like reference characters designate the same parts in the several views,

Fig. 1 is a plan view of the preferred form of my invention illustrating a portion of the of association of the arch block therewith,

Fig. 6 is a sectional view taken on line 6-6 ofFig. 5, I Y

Fig. '7 is a perspective view of the single form of skewback as illustrated in Fig. 1, v

Fig. 8 is a perspective View of a modified form of arch blocks wherein the block is positioned midway between the beams on a support with a form being employed to permit the pouring of a concrete construction in situ of a character similar to the skewbacks, in order that the beams be protected thereby in the same manner as the protection afforded by the skewbacks, Fig. 9 is a sectional view taken on line .99

Fig. 10 is a top plan View of a precast block adapted for use for cooperation with the'place ofjuncture of a girder anda beam,

M Fig. 11 is a perspective view of the form of block for application along the girder, a series of such blocks abutting each end arch block,

Fig. 12 is a sectional iew through the blocks illust ra'ted in Fig. 10,

Fig. 13 is a side elevation of the block illustrated in Fig. 10,

Fig. 14 is a plan view of a modified form of construction illustrating elongated skewbacks showing the blocks in position,

Fig. 15 is a sectional view taken on line 15-15 of Fig. 14,

Fig. 16 is a view illustrating a modified form of arch block in position,

Fig. 17 is a transverse sectional View taken on line 1717 of Fig. 16,

Fig. 18 is a view illustrating the manner of reinforcing any form of block with eyelet or screen reinforcements,

Fig. 19 is a plan view of the preferred form of supporting framework in position upon the steel framework,

Fig. 20 is a perspective view of a portion of the supporting clamp illustrated in Fig. 19, and

Fig. 21 illustrates a further modification.

Referring to the drawings in detail, the numeral 1 designates a fireproof floor embodying the preferred form of the invention. The construction encases the usual steel framework including girders 2 and beams 3. It is contemplated that the dimensions of the said framework be standardized for the most efficient practice of the invention, but varying dimensions may be employed.

In the forms of the invention illustrated in Figs. 1, 14 and 16, blocks 4 which are in the nature of skewbacks, are mounted to extend along the sides of the beams 3. Each block 4 is longitudinally recessed at 5 to receive the lower flange 6 of the beam 3. As illustrated it will be seen that upon the placing of blocks or skewbacks 4 on opposite sides of a beam, the lower extending portions '7 of said skewbacks cooperate with each other to substantially wholly enclose the lower flange of the beam.

As may be observed, each skewback 4 contacts with the web 8 of its supporting beam, and the extending portions '7 of oppositely arranged blocks substantially meet at the center line of the beam. The extending portion of any of the skewbacks i may be beveled upwardly and inwardly to form keys for mortar or plaster. In actual construction the thickness of the extensions '7 normally vary from one and one half to two inches although the thickness of the extensions may be varied according to the code requirements in any particular locality. In the preferred form of the invention as illustrated in Figs. 1 to 6 inclusive, arch blocks 9 are provided for spanning the space between opposite skewbacks i. The skewbacks 1 and arch blocks 9 have corresponding depressions 10 and 11 respectively in the ends thereof extending from their upper edges to points adjacent the plane of the flanges 6 of the beams 3. The contacting or abutting end surfaces of the skewbacks 4 and arch blocks 9 indicated at 12 are angularly disposed with respect to the webs 8 of the beams 3, and in order that maximum strength be had it is important that the angles be on radial lines with respect to the adjacent upper arched surfaces of the skewbacks 4 and arch blocks 9.

In order that the construction provide the necessary strength, the proportioning of the skewbacks 4 and the arch blocks 9 is determined by the width or spacing of the beams 3. In normal construction the beams '3 if 10 inches high are spaced-5 feet apart, while 12 inch beams are spaced 6 feet apart, the spacing increasing one foot for each two inch increase in the height of the beams. In a construction of such proportlons it is preferred that the arcs scribed by the upper surfaces of the skewbacks and arch blocks intercept the webs 8 of the beams 3 atpoints slightly above the center of the same. In the preferred form it is desirable that these points of interception be not greater than two-thirds the height of the webs of the beams and that the arcs scribedby the arch blocks have their uppermost portions to or just below the upper surfaces of the flanges of the beams 3 .so that the blocks do not interfere with the laying of the floor and yet permit of a strong construction as a result of the angular contacts between the skewbacks and blocks 9 and the wide contacting surfaces between the ends of the skewbacks and the webs 8 of the beams 3; i

Both the skewbacks 4 and the arch blocks 9 are provided with core holes 13 and 14 respectively, the core holes providing air chambers which result in the lightening thereof and effecting sound and fire insulation without destroying the strength of the same. The core holes are slightly tapered since in the manufacture of the blocks the cores are more easily removed when tapered. Throughout the construction of each of the blocks, the cornersexisting both on the interior and the exterior are rounded for the purpose of reducing the formation of cracks and chips. 1

As illustrated in Fig. 3, the arch blocks 9 are normally arranged in pairs and each has an upper recess 15 which is in alignment with the recesses 16 in the skewbacks 4. a For the purpose of eliminating the necessity of having a large variety of skewbacks depending upon the type of arch blocks to be employed, each 'of the skewbacks is provided with a corresponding recess 17. In the preferred form reinforcing bars 18 as illustrated in Fig.2 are employed, the bars partially resting in the grooves provided by the cooperating recesses 15 in adjacent arch blocks, and

having low folded ends extending between adjacent skewbacks which thereafter terminate in extended portions passing over the upper flanges of the beams with whichthey cooperatel I The placing of the preferred form of each block and skewback in position forpermanent association'in the building will be hereinafter described fsubsequentto the'description of the blocks illustrated in FigureslO ,to 13 inclusive, which are arranged in position before the remaining blocks are mounted.

The precast blocks as illustrated in Figs. 10, 12 and 13 are adapted for association at the points of junction of the girders 2 with the beams 3. As the girders 2 are of a greater height than the beams 3, and as the beams are secured thereto so that the upper flanges thereof. are in substantial alignment, the lower flanges 6 of the beams must necessarily be in higher plane than the flanges 19 of the girders. Each block 20 is therefore provided with a groove 21 adapted to receive one side of a flange 19, when in position with the portion 22 thereof extending below the same to a point substantially midway of the girder in order that it cooperate with a similar portion on an oppositely disposed block 20 for effecting the substantial enclosure of the flange 19 of the girder. Arranged at right angles to the groove 21, and above said groove a suificient distance to be in a position to receive a flangeo of a beam 9, is a groove 23.

which will form with a cooperating block a substantial enclosure for the portion of the flange 6 with which it is in contact. Grooves 24 and 25 arranged verticallyin the sides of the blocks 20 communicate with said grooves 21 and 23, and thebuter faces bordering the same bear against the webs 26 and 8 of the respective girder 2 and beam .3. The blocks 20 are formed with core depressions 27 which provide air chambers, the core depressions being tapered and the corners thereof being rounded for the purpose previously specified.

A series of blocks, one of which is illustrated in Fig. 3.1, each has a groove 29 corresponding to the groove 21 in blocks 20, which groove is adapted to fit over the flange 19 of a girder 2. Theblock 28 next adjacent to block 20 bears thereagainst, while additional blocks 28 abut against one another throughout the space along the girder between the beams. When another beam is reached a block 20 is employed at the juncture thereof with the girder. A groove 30 similar to the grooves 24 in the blocks 20 is provided in each of the blocks 28, and core recesses 31 are also provided.

In order to permit the ready association of the blocks with the steel framework a support indicated at 32 is provided. The support comprises four clamps 33, each having a base 34, upright arms 35, and a connecting bearing bar 36. The base is provided with openings 87 and 38 respectively and is reinforced directly therebelow with a bar 39. A yoke 40 forms a part of each clamp, each yoke being adapted to have its arms pass through openings 37 and 38 of its respective base with the connecting bar thereof passing over one of the beams. The arm fartherest spaced from the yoke 40 is provided with a screw threaded opening 41 for the reception of a set screw 42. In practice each yoke is placed over the respective beam with the arms thereof passing through the openings 37 and 38 in its base 34, with wing nuts 43 thereon to permit the'tight adjustment to the beam. A bar 44 is then passed through cooperating clamps and seated upon bases 34 whereupon set screws 42 are tightened to maintain the bar in place. The other, pair of clamps which, as stated, have been similarly applied have a bar 45 arranged therein, and a series'of cross supports 46 may thereafter be arranged across bars 44 and 45 in accordance with the needs of the particular operation.

After the support 32 has been placed in position the blocks 29 are applied at the juncture of the girder and beams respectively and the blocks 28 applied along the girder. Oppositely disposed shewbacks are then placed in position for thereception of an arch block 9. Concrete or mortar may be used to help secure the blocks 20 and 28 in position, but it is preferable to abut the skewbacks 4 and the arch block 9 thereagainst without the application of mortar or concrete. The recesses 1c and 11 in the skewbacks 4 and arch block 9 are filled with concrete to thereby lend greater strength to the construction and prevent relative movement. abutted against the blocks 28 with the recess 15 thereof spaced from said blocks. The next adjacent skew'backs are then applied and the arch blocks 9 positioned with the recess 15 adjacent the corresponding recess 15. The blocksmay thus be formed in units wherein if desired cement .or mortar can be applied along the faces adjacent the recesses of the arch blocks 9 for securing the The said arch block 9 is I blocks of the unit together. The remainder of the particular section in the framework may now be continued in the identical formation of units until the blocks 20 and 28 at the-next adjacent girder are reached. The reinforcing bars 18 may now be applied by partially laying them within the grooves formed by the recesses 15 with their ends engaging the beams as illustrated in Fig. 2. The skewbacks are each provided with vertical grooves so that they can be placed in close contact without binding the yokes 40. Grooves, of course, are also necessary for the passage of the folded ends of the reinforcing bars. A layer of poured concrete or other mixtures extending to a desired depth over the upper flanges of the girders 2 and beams 3 which has been applied to provide the floor 48, encases the reinforcing bars 18 and securely maintains the units in position.

It will be seen that the above described construction provides a rigid arch arrangement which is comparatively light in weight, one in which the steel framework is completely covered and protected in the event of fire, one in which the heat and sound conducting properties between upper and lower floors is materially reduced, and one which may be readily assembled resulting in a saving of time in building and in which only a very limited number of different types of precast blocks are necessary in the construction of the entire building. Furthermore, by the construction thus far described the ceiling will be unobstructed in accordance with the code requirements in certain localities. v

A modified form of arch blocks is illustrated in Fig. 8, and in this form the block 49 has reinforcing bars 50 and 51 respectively passing through the lower wall 52. Each end of the reinforcing bars is bent upwardly substantially parallel to the end face of the block 19 from which it extends as indicated at 53. The arch block 49 may be used in conjunction with the blocks 20 and 23 which are applied to the girder 2 as specified above, the block 49, in the course of constructing the building, resting upon the cross supports 46 while concrete is poured into position in place of the skewbacks for securing the arch block to the beams.

In this modification a concrete form is necessary and. the concrete when poured engages under the flanges in the same manner as the skewbacks for protecting the same. The reinforcing bars 50 and 51 have their ends embedded in the poured concrete to lend greater strength to the connection between the arch block: 49 and the poured concrete.

The modification illustrated in Fig. 14 comprises arch blocks 54 which may be somewhat shorter than the arch blocks illustrated in Fig. 1. The arch blocks 54 are provided with recesses 55 at each end, and skewbacks 56 of an elongated formation are provided for cooperation with the shortened arch blocks. In practice this modified form of block is employed in combination with the blocks 20 and 28 in the same manner as previously described, this particular modification employing two reinforcing bars 5'7 partially lying in the grooves formed by the recesses 58,'and reinforcing cross bars 59 arranged in pairs in the recesses 55, which cross bars extend only across the width of two sets of blocks for the purpose of providing the ultimate formation of a unit of said set of blocks with adjacent sets of blocks forming other independent units. The poured concrete forming the floor is applied in the same manner as above described.

Figs. 16 and 1'7 illustrate a different type of arch block wherein reinforcements are not em played. The arch block 60 of this modified form has the core openings thereof partially closed at one side of the block and the walls thereof are rounded into one another. By the construction of the arch block 60 more complete air chambers are provided with a greater resistance to the conduction of heat and sound. At the same time this construction provides greater strength. The arch block 60 may be employed with the skewback as illustrated in Fig. 1 or it may be employed in combination with a single skewback adapted to extend the full width of and cooperate with two arch blocks. The construction employing the arch block 60 is completed in the same manner as described with respect to Fig. 1.

When desired a double skewback may be employed in connection with any of the forms of arch blocks illustrated, for in each proposed construction two arch blocks are so associated that they provide the main structure of separate units in use. While the poured concrete constituting the floor and the plaster coating applied to the underside to form the ceiling extends over a series of the units, nevertheless by arranging the units separately the expansion and contracting thereof is transmitted directly and proportionately to the upper concrete and to the lower plaster, whereby the formation of cracks is eliminated or materially reduced. Whereas, if the blocks between the beams and girders of the steel framework were formed into a single unit the expansion and contraction of the entire unit would be transmitted to some one point so that a resultant crack in the plaster of the ceiling or the concrete of the floor would be practically unavoidable.

Fig. 21 illustrates the modification wherein a skewback 51 which may be of the single or double length is employed inorder that an obstructed ceiling effect be produced. The skewback 61 is provided with a groove or recess 62 adapted to engage over the flange 6 of the beam 3. The portion 63 extends under the flange 6 in the same manner as the lower extending portion engages under the flange 6 in the other forms of the invention, and the oppositely disposed flange 63 of another skewback 61 may be arranged so as to completely encase the lower portion of the beam. The skewback 61 is provided with a groove 64 on the face thereof adjacent the web 8 of the beam 3 and is provided with a recess 65 on each side thereof to permit the passage of the arms of the clamp yokes 40.

The portion 66 of the skewback 61 is reduced to provide the shoulder 67. An arch block 68 of relatively low height is arranged for engagement with the portion 66, recesses 69 and '70 being provided in the skewback and arch block respectively for the reception of concrete. It will be seen by this construction that upon the building being arranged with the concrete fioor portion and the plaster ceiling that an obstructed ceiling giving the appearance of the normal obstructed ceiling will be provided, but that the building can be constructed in a greatly reduced time from a light construction having the required strength.

Each of the blocks, both the arch blocks and the skewbacks may be provided with reinforcing members 71 formed of eyelets or in some instances metal lath. The sections of eyelets may be arranged as illustrated in Fig. 18 or in any other manner so long as the strength desired is effected by the arrangement.

This application'is a continuation in part of my (ill application, Serial Number 267,941, fi1ed April 6, 1928.

What I claim is:--

1. A fireproof. floor construction encasing a framework, said'construction comprising precast blocks having cement as a binder, said blocks-being set in and surrounding the framework, said blocks comprising skewbacks enclosing and supe ported onthe lower flanges of the framework said skewbacks. beingeach at least as thick as the flanges are wide, and other blocks spanning the skewbacks forming a ceiling free of depressions between the flanges, the upper surfaces of the skewbacks and the other blocks forming one uniform and continuous curved surface.

2. The herein described fireproof floor construction including a steel framework, the same comprising girders and spaced beams connected thereto, precast arch forming blocks comprising skewbacks supported on the lower flanges of the beams and enclosing the same, said skewbacks abutting against the webs of the beams, other blocks spanning the skewbacks, forming a ceiling free from channel formations between the said beams, and still other blocks enclosing the lower flanges and web portions of the girders, the last mentioned blocks laterally abutting the ends of the arch forming blocks against disengagement from the girders.

3. A device of the character described including blocks encasing a steel framework, the latter comprising spaced beams and girders, precast blocks having cement or other suitable material, as a binder, said blocks including two sets, where- Iof one set encloses the lower portions of the beams and form arches extending in side by side relation between the beams, the other set enclosing the lower portions of the girders, the blocks last referred to having lateral interlocking engagement with the ends of the arch forming blocks to be retained in engagement with the girders.

4. A fireproof floor construction including precast blocks of concrete, or the like, a steel framework comprising girders and beams connected thereinto, said blocks coacting to form arches supported by the beams and abutting laterally against the webs thereof, the said arches includ ing skewbacks, the said skewbacks having longitudinal recesses enclosing the lower flanges of the beams there being a plurality of arch blocks disposed in side by side relation and in an engagement with a single or series of skewbacks, precast girder blocks of concrete, or the like, enclosing the lower flanges of the girders, said girder blocks having upward projecting portions adjacent to the webs of the girders, the arches being spaced from the girder webs to provide space for the said portions, said arches abutting laterally against the said portions to lock the girder blocks in place, and a cement binder between the meeting surfaces of the blocks.

5. A fireproof construction including a steel framework, said framework comprising girders and spaced beams connected thereto, precast blocks comprising skewbacks supported by the beams, each skewback being recessed between its intermediate portion and the lower face thereof and having the lower flanges of its respective supporting beam received in the recess, the face of each skewback above the recess bearing against the web of the respective beam and extending upwardly along the major portion of said web, arch blocks each having upper, lower and end walls with webs connecting the upper and lower walls spanning cooperating skewbacks with the upper wall scribing an are which interceptsthe respective beams at points abovethe center of the webs thereof, the surfaces of contact between the respective arch blocks and the skewbacks being arranged at right angles to the arcs of the upper walls of the arch blocks at the ends thereof with said surfaces of contact extending from points below the lower flanges thereof, whereby the lower flanges and webs of the beams coact to support the precastblocks'in position and the strain of support is evenly distributed.

- 6,, A fireproof floor construction includi ng beams, precast blocks of concrete or the like bearing against respective beams and being supported thereby, arch blocks spanning the first mentioned blocks, and reinforcing bars having their ends engaging over adjacent beams with portions extending down against the webs of the beams and folded upon themselves with the central portion thereof being arranged adjacent the line of contact between adjacent arch blocks.

7. A fireproof floor construction including beams, precast blocks of concrete or the like engaging respective beams and being supported thereby, arch blocks spanning the first mentioned blocks and reinforcing bars arranged in recesses in the blocks adjacent to the lines of contact between adjacent arch blocks and adjacent the lines of contact between the ends of the arch blocks and the first mentioned blocks.

8. A fireproof floor construction including beams, arch blocks arranged between the beams, means extending between the beams and the ends of the arch blocks for engaging the beams and supporting the arch blocks therefrom, and reinforcing elements extending throughout the length of the arch blocks and being embedded in the means which engage the beams.

9. A corner block for fireproof floor construction which includes beams and girders arranged at right angles to each other, which comprises a body portion recessed adjacent its lower end for the reception of the flange of the girder and recessed on a perpendicular wall above the first mentioned recess for the reception of the lower flange of the beam whereby the block when in position has flanged portions which extend partly over the lower flange of the beam and the lower flange of the girder.

10. In a fireproof floor construction encasing a framework, said construction comprising precast blocks having cement as a binder, said blocks comprising skewbacks enclosing and supported on the lower flanges of the framework and bearing against the webs thereof throughout a material portion of the height of the webs, said skewbacks each being as thick as said lower flanges are wide, and other blocks spanning the skewbacks forming a ceiling free of depressions between the flanges, the upper surfaces of the skewbacks and the other blocks forming one uniform and continuous curved surface.

11. A device of the character described including precast blocks having cement or other suitable material as a binder, a steel framework having the members thereof extending at angles to beams having lower flanges, precast blocks of concrete or the like engaging the beams throughout only a portion of their height and being supported thereby, arch blocks spanning the first mentioned blocks andhaving an upper curved surface, and reinforcing bars secured to the beams and arranged adjacent the line of contact between respective arch blocks, said reinforcing bars following the curved contour of the arched blocks and engaging the lower portions of the beams.

ERNESTO FIORDELISI.

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