US2477256A

US2477256A - Cantilever floor structure

Info

Publication number: US2477256A
Application number: US774616A
Authority: US
Inventors: Frank N Kneas
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-09-17
Filing date: 1947-09-17
Publication date: 1949-07-26
Anticipated expiration: 1966-07-26

Description

July 26, 1949. F. N. KNEAS CANTILEVER FLOOR STRUCTURE 4 Shee ts-Sheet 1 Filed Sept. 17, 1947 July 26, 1949. F. N. KN EAS 2,477,256

I CANTILEVER FLOOR STRUCTURE I Filed Sept. 17, 1947 4 Sheets-Sheet 2 Jul 26, 1949. F, N, KNEAS 2,477,256

CANTILEVER FLOOR STRUCTURE Filed Sept. 17, 1947 I 4 Sheets-Sheet 5 July 26, 1949. F. N. KNEAS CAN1'ILEVER FLOOR STRUCTURE Filed Sept. 1'7, 1947 4 Sheets-Sheet 4 I INVENTOR j wz$ Ail news Patented July 26, 1949 moon sranc'rm i mmnrnmn rnnaa ipma, Pa. 7 applieamsemmmi'z, 194i, SeriaLNO, 214,616.

The present invention relates to a system c! fioor framingaccuratelyspace A of novel design for the support or erectionloads= .9 c1. we -15 during the construction oiireinfjorced concrete" floor slabs resting, on the platforms. th spe under the floor slab between the platforms faciir-f tating the installation of ducts longitudinally and transversely in a building.

My invention difiers from, and ments over any type heretofore used; structural. metal columns ofi'or 3t with projecting strnctura'l'metai yard-armsateaclr" 1 floor level attached to 7' them i'n theiahricating shops it speeds erection and'tohtains maxinimn usable floor space.

By using cantllever ended floor duces the maximum momentsji'n the fioorheams".

and in the columns without incnrrmg thedangerst inherent in. continuous beams and allbws, ail: stresses to be computed by simpleformnlasi It provides a. series of structural metal platforms or" panels formed by; pairs ofcantfiver-endiedffloor beams spanning between 'andisupported byyardf'- arms and connecting two ormore columns at eachfloor level which, duringerection-wiihsupport men'and erection equipment and after'erecticrr will form'the supports, ofthe permanenfifltior'f slabs.

tudlnaland transverse slots can reaeily -be provided' without cutting' main reinforcement beset ting, up unknown stresses in the slats.

invention provides spaces whieh -longi My invention further provides a system yofj framing facilitating the installation gitudinal'ly and transversely under-the em gratigirders and without incurring; the of the flatsiab'system;

Further pnrposes of my inventiorrj'wi-l appear in' the development the specification and claims.

Figure I is a perspective viewshewing arpafi tial building (frame of -encased metal-columns" supporting pairs of longitudinally cane tilever beamsgwith' spaces in line. with anti-fietweenthein.

Eigure 2. is an. enlargedliragmentam 'i plan view parallel to theQflhor showingt-pamthoii thestructureot Figure-1.

takemuponlinezte-h.

Eigures ate 7,, inclusive; arezfiragmentary topi plans views: shrmziazig at new difieremti reinimicments of a.-'coneretesfioonisl'abzi ritssibcaiflom'hestweenthe-ends ofi'the'icantiienerisbeamsra Figure 8 is a fragmentary top plan viewing edit-sting members. a

just-merits of Figured;

. v 3% without passingunder a grid-ironofbee msg-andf Figure 3- is; a. fragmentary namel v 1 F Figure I0 is a section of Figure 'onz'the line llli' ,lllj

In'the drawings 5 parts:

For the purpose ofdericription, I callthe "direction along. the axes of'the cantilever-ended floor; beams, the, longitudinal direction of the'fl buildinjg, anri'iijhefdirection' atright angles, the

transverse direction.

Inmir inventioIL ,I.use str nmns, eachof which is composed of 'asi'ngleselfi contained unit such as .a rolled structural metal section" of Hi shape .adaptedlboth to. carry vertical loads'and to resist lateral forces.

Each 3H -shaped column is composed of a single" 7 ihavingfian'ges on each side extending from a 'central' web" a sufficient distance to" receive 1 rivets,, jho1ts,' or other.connectingdevices for the ataclmtrent of the 'irorizontal proj'ecting members whichrcaliyard 'arrns and which do away with theyard arms of pairs ofstructuratmetal col urn'nsandiextend'beyondithe yard ar s tobecome cantilever, ended floor beams to. form structural" metahpi'atforms at each floor: level. Reinforcedf concrete slabs span between the fio'or beams.

The cantilever-ended floor beams, ofluniiorm'" depths thronghout'their lengths, are spacediby.

arms are prevented from revolvingaround' their longitudihalfaxes; they thus form rigidly fixed;

and"uniformly:spaceifabutments for the trans- Th'e. cantilever-ended; structural" metalfloor beams are. preferably constructed. of rolled strisc tural' 'rnetal"sections which are readily obtainable with vertical webs, having flangesextending laterailyat'their top-and at'thei'r bottom edges. Thus they obviate the necessity, of using bent; or

paforatedtrough shapes, and" provide broadrfi'at" surfaces attheir tops toform bearings for the transverse slabsand the transverset'bands 'ofreinterned concrete: "[The bottom flanges fblll'l'l shelvesfromwhich reinforced"concretehaunches can ne formed to providetfurther-support'fortthe" transverse slabs and The: top and bottom fianaesof the'structural m'etal fioorbeamsbeing inrilar numeralsindicate like thecoiumns in the fabricating shop. After the columns: withtheir, yard. arms are erected; beamsare'attached the 'fiel'dto the ends'oi theyardfarms away from the columns and. their lrigid attachment'to the ends of the verse concrete slabs, that span the clear spaces, from heanrtloheam.

3 solidly connected to the web by fillets, provide lateral support against arch action, that may be imposed by the transverse slabs and bands and they also provide resistance against torsion in the transverse direction. The bending moments, that occur in the said transverse slabs and bands, whether caused by vertical loads on the floor slabs or by lateral transverse wind, orother pressures, on the structure, are reduced'by this torsional resistance.

ing and are supported on the cantilever endsofthe cantilever-ended floor beams. These crossbands carry floor slabs which are called sus-, pended slabs, and span longitudinally between. the cross-bands. The load from the suspended slab and from the transverse bands are thus applied on the cantilever ends of the cantilever ended floor beams. Great economy in the use of structural metal is obtained by my invention; be

cause the end moment due to loadson the canti lever portion of the cantilever-ended floor beam reduces the moment due to loads on the central portion of the floor beam. shallower and lighter beams can be used on account of these reduced moments, as compared with beams which are simply supported at each end in the rd of structural metal skeletons.

By properly proportioning the lengths of .the cantilevers, and the lengths of the suspended slabs, bending moment to a greater or less degree can be induced in the cantilevers, reducing, or

increasing, the bending moments in the central portions of. the cantilever-ended floor beams,,until the most favorable balance of moments is reached in the design, which is enerally when the mo.- ment on the cantilever portion of the floor-beam becomes the same as the moment on the central portion.

This is a great improvement over floor construction, such as used in so-called fiat slab construction, in which single, free-standing, rein-. forced concrete columns are used, having flared heads, or brackets, which project from the faces of the column and support the floor slab. In the latter case, an unbalanced floor load placed. .on

the slab on one side of the column, tends to de press the slab on that side and causes bending in the column without favorable reduction in moments in the slab on the other side of the column.

The H-shaped columns are less resistant in the direction of the axes of the flanges than in thedirection of the webs. I, therefore, place the axes of the flanges parallel to the longitudinal floor beams whose continuity between, columns, and

their extension into cantilever ends, reduces the bending in the columns, should any unequal loading on the floor occur in the longitudinal direction. The greater resistance of the columns is in the transverse direction, where it is best adapted to resist the bending moments that occur, should 1 any unequal loading occur in the transverse direction. The bending moments in the transversev direction are further resisted by the heavily rein-1 forced transverse bands.

Furthermore, since the columns continue unin terrupted through the connections for the yard arms into the story above, the bending is divided at each floor level between the column section that extends below the floor and the colum tion that extends above the floor.

At the top of the building, thesnow load light, and may be considered as uniformly dis- .-,;10 Transverse, or cross-bandsof reinforced concrete run in the transverse direction of the build B ee tributed, so that no bending occurs in the top section of the column, which does not continue above the roof.

Inthe completedconstruction, allof the struc- 5 tural inietalrimembers are. generally encased in reinforced concrete. The encasements of the 1 beams and yard arms are integrally connected with the reinforced concrete floor slabs. Each pair ofsteelcolumns, with their yard arms, con- -=nected.by cantilever-ended floor beams, provides at each floor level a structural metal supported reinforced concrete platform, or island, which is connected to other similar platforms by reinforced concrete slabs spanning transversely. The longitudinal axis of each platform is located by the center-line of the two columns connected by the-pair, of" cantilever-ended floor beams. The,

length of the platform 'is' equal to the length of the cantilever-ended floor beams; and the width is determined by the dimension 'out-to-out of the pair ofconcrte encased floor beams supported by the yard arms on' each of the connected columns. I I

At the e'nds'of the cantilevers, which form the structural metal platform, a large and abrupt change in the depth of construction is provided between the deep structural metal beam and the shallow reinforced concrete longitudinal floor slab that is suspended between the transverse bands. 'The equivalent of a hinge is thus obtainedat each end of the cantilever-ended floor beams. The transverse bands, which are also shallow, allow a certain amount of torsional rotation around their axes, without causing serious internaljstressesf- In the transverse direction, assuming that the center-to-center distance of adjacent concrete platforms is predetermined, the span of the transverse slab and the'transve'rse bands between adjacent platforms can be altered by altering the length of the yard arms. If the lengths of the yard arms are increased, the span of the transverseslab anclbands between-adjacent platforms is reduced. At the same time, lengthening the "yard arms increased the span of the platform slab between the beams supported from the ends of the yard arms on each side of the columns. The most economicahand desirable ratio of spans of slabsgand transverse bands can thus be obtained 5 by altering thelengths of the yard arms.

In the transverse direction, there is an abrupt change in depth between the concrete encased structuralmetal beams at the edges of the plat- ,form and 55 the beams.

There is thus produced, in effect, a series of rigidly supported, reinforced concrete, platforms or panels connected, both in the longitudinal and transverse directions with other similar platforms by reinforced concrete slabs of much less depth than the beams providing a hinged efiect on all edges of theplatform by abrupt changes in depths and deflectioncoefficients.

6 There is thus provided asafeguard against beams were made continuous, and if changes in alignment were caused by unequal settlements in column footings, or caused by unequal compression in the supporting columns, due to un- 7 equal loadings-on the floors of a multi-story building. 1

The yard arms can be connected to the column lathe-fabricating shop where more accurate the transverse slab that spans between nknown stresses that would be set up if the v7 assembly is possible than in theefieldr Each (201- umn may be of two or three story lengths with c m-aces:

yard iarmseattachedcat internals. that correspond:

to the accurate story heights. "This shop fab.riea. tiorr also reduces the amount of work? necessary; in the field. Each column is fabricated as a continuous unit without :the. necessity for interruption :ior the insertion of short. sections. :to carry brackets to-the column.

Thecolumns .of each. connectin pair are accurately spaced on column centers and held-.1 there by the cantilever-ended beams which are connected to .the ends .of the yardarms at each floor level. The beams form rigidbents with the columns :which are thuskept. plumb and .true. during xerection.

It is necessary during the construction of a multi-story building to raise the hoisting apparatus; such'as .derricks, etc., to the upper vfloor levels as the erection proceeds. The rigid bents. or platforms formed bythe cantilever-ended floor beams, connecting the ,yard'arms and 001-. umns iat .each floor level; form platform frames onewhich'timbers and planks .can be erected to. form working spacescn'which the hoistinsallparatus .can be placed and. around-which the raising gangsican workl In my invention;.I.-. rovide against, wind mo-.. mentsldurmg construction .in:..-the longitudinal directions by connecting pairs .of columns through their yard arms :by the cantilever-ended beams; each pair of the cantilever-ended beams iniointactiom with the conneetedrcolumns forming a bent 1thatgwill resist the wind. Heavy anchars-between :the bases of the columns and :the foQtingaresi-stlateral forces in the transverse direction... r

These bents formed by columns connected :by'. the cantilevereended. floor beams through the yard arms notionly resist Wind during construe-.- tionpbut alsoafter completion. Inthe transverse direction, after the structure is completed, additional wind resisting .bents are formed bythe reinforced cross-bands between the cantilever ends of the c antileverended floor beams. Furthermore. when transverse forces act: against the completed -.str.uctu.11e,- :the cantilever-ended floor beams being rigidly spaced and held away from; fiflOIH I I -IbY the yard arms tend to.be.defiected downward .for their full length: end-thecward sid and upward on. theuwindward side producing ImifOIm endingstresses in the 'transv rse bands and s,labs. :for the full lengths :of the cantilevereended floor beams. This provides more resistance togla'teralforces; than the, limited areas of zfiQOI.S19.-bS around the. column heads in: typical reinforced concrete flat-slab. construction.v Iii-my invention.. while bothyard arms and beams extend below the bottom of thefloor slab, spaces or gaps are provided both inthelongitudinal andthe transverse. direction, .wherethere. is 1:10. projection below 1 the floor slab- Ducts attached to the underside of the slab can pass through these spaces or gaps without projecting below the bottomoi-the longitudinal floor beams orthe transverse-yard arms, so that the-clear head room from the underside of the duct will proximate the clear-heights from the underside of the beams to the floor below.

In the longitudinal direction spaces .or gaps are provided under the slab between the ends of the cantilevers. of con ecutive platforms, in which transverse d s can e placedunder .the. slab but above the level of the bottoms of theiloor beams..- Lnthe transverse direction spaces. are provided under the .slabbetween the sides of ;;the. floor; beams of adiaoent bents, inwhi hloneitudinal1 the level of the bottoms of the floor beams- 7 5'? to provide the holes throughthe deep llaredhe'ads' 'tur-al metal or concrete the beams and girc ducts can be erected under-the slab-end above These clear spaceszbetvvieenthelplatferms are not interrupted as theyare ord n r f m d ldings with beams and cross girders either of structural metal, or -of reinforced concrete.v

In. modernbuildings with large areas of floor pace,-=;w-ith desks arr n ed-in. longitudinal and.

transverse rows, it isanfloessa ty'torprouide. tele phone connections: ateach deskand to make provision. for other; servicesv such as. electric light and el ctric service. for adding machines, comp:

tometers, and other modern office devices. .To

avoid overheadwiring.,,it is desirable to run cond'uits, or under-floor ducts. in longitudinal and transverserows, in the 'floor slab; to line p with the desks. It is very. necessary that the rein.- forcement inwthefloorslabrbe .so arranged as to allow the placingoi the conduits without interference ;-with the reinforcement. is made difiicult in flat slabconstruction because the :main

reinforcement occurs radially; or at right angles, or in diagonals, in checkerboard, areas. .over the floor areas where .the reinforcement is concen .trated over thecolumn heads- In my invention the main reiniorcement spans transversely from structural metal platform to structural metal platform across. the .full width of the building; There isthus formed a broad .strip of. floor slab as wide-asthe. cantilever-ended floor beams are...1ong, in. which the .maln .reinforcement spans in the transverse direction. The

transverse bands across the cantilever .end form a kind of selvage at theedgesioi the strip.

Frolnzthe transversebands the main rein-force-v ment of the suspended slab spans in the/longitudinal direction." There is thus ,formed. abroad strip of floor slab extendins-theiull width of. the 1 building in which the-reiniorcement spans in the longitudinal direction.

In many spacial .typesoi buildings it'is .neces-.

sary to providelongitudinal openings or slots tl'iroughv the floor slabs through which inter-communication cables, or ducts, may bepassed. Since, in my invention, longitudinally reinforced suspendedslabs occur atzregular intervals betweentransverse bands, these slabs form ideal moat-ions fol the longitudinalslots. In these suspended' sla'bs the slots require that only one or ,tworods'parallel to the slot be -omitted.- Neither omission nor cutting of the main transverse reinforcement is necessary in the full length of the slot which may-extend from-band to band Since the bands extend thefull width of the building;

numerous longitudinalslots can be provided in the building without Weakeningof the 'construc* tion; V

It frequently becomes necessary to have vertical runs of pipes. ducts, or down-spouts, or other mechanical features through successive" floors in the interior bays. The least interference is caused to the .occupancies anduser's of the building whenthese required runs can be placed close ly adjacent to the columnjsfpreierably where they can be .included in the furringaround the columns, or in the partitions abutting the-columns, the most desirablelocationbeing generally close to the center of oneof the faces .ofthe columns.

In the ordinary framed construction of; struc-.

frame into the columns on the center lines and thus block the desired losationsior the runs;

In the flat-slab. construction it is. not desirable the center lines. W

In my; invention thedesired spacesfor the vertical runs are kept clear because the channel yard arms are spaced away: from the-center lines of the columnsbeyon'd the edges of the flanges, thus providing spaces which allow holes through the floors opposite -.the' column fiangeswithout weak eni'ng thestructure'inanyway. In the other direction, the yard'arms space the longitudinal beamsaway from the columns in thestransverse direction;- allowing ample spaces for holes without weakening thestructure.

In structural metal framed structures :with beams and girders framing betweenthe columns, itis often difiiculttobring-thacolumnsto plumb, truelines, because of minor discrepancies and tolerations in the shop-Work and because of the lack of adjustment in'the lengths-ofthebeams and girders." Therefore, 'to makefield corrections, it is necessaryto driftand ream theholes connecting themembers and to use oversize rivets, filler plates; or othercostly means for making adjustments. In my invention the successive columns with their platforms areconnectedby adjustable' members= -in both the longitudinal and the transverse direbtions. These adjustable membersare preferably made in-the form of rods with long threads on each end-on which nuts operate to draw the platforms into true and correct relation to each other" and to hold them firmly in position..-..These adjustable members are installed within the limits of the thicknesses of the slabs and the transverse bands, and after the concrete is poured, :they -form: additional reinforcement... :5: c

Rivets have numerous advantages over other connecting devices, but the noise of riveting in the field is. objectionableandriveting should be done as far as possible in the fabricating shop. In my invention the number of rivets necessary to be driven in the field is reduced because the yard arms. which, take the. placaof girders used in beam andgirdenconstruction, areriveted to the columns in the shop.

Upon or beneath the floor-.10 are mounted a plurality of columns ll,.of which columns H are interior columns andcolumns I l are exterior columns. The columns and the, other metallic parts to be described are,made. of structural metal, such as structural steel or structural aluminumalloy. 51-1, a 1.

As the illustrationis intended to be a general one,floor, l representsbutone floor cf;a number of floors which might be served by the same CO1? umnsextending .above it as. at-HF, Figure 1 to the height of the building. It is assumed that both floors, l0 and i0, illustrated are intermediate fioors. i

Longitudinally extending facing spaced pairs of beams l2, and I3 are illustrated along with their supporting yard arms [4 and 15. Between the facing ends of each pair is a space or gap l6. In this particular illustration, the columns comprise structural metal shapes 1! such as H-beams, protected by concrete fire resisting encasements l8, which may be reinforced concrete, if desired.

For the purpose of showing one way in which the yard arms may be supported from the structural metal columns and one way in which the beams are supported from the yard arms, without suggesting that either is the only way, Figures 2 and 3 have been inserted to illustrate an acceptable structure of the type. The columns I! are illustrated as H columns or I columns, which are a": united to the webs} back channels l9 by. angles 20. .Correspondinglythe channel webs [9 are .unitedto the webs.2l of H- beams or I-beams 22 by angles 23.

ceptable and generally. preferred form of connection between columns and cantilever beams and have beensele tedffor that reason 3,518, generic 10 I'he' fire resistant encasement 18 has been bro-F. ken away in Figure 2 to showv the metal column ll. and'the bracketing lfi by which the yardarm channels: (Bare connected to the metal column. No point has been made of the character of coninectiongwhethei itbe by boltsor by rivets or by welding. However, rivets 2d. are shown as a desirable form. Thejoint is also fire resistant concrete at l8.

The yard arm itselfis en 20, sistant' concrete at l8.

=The bracketing of the .yard arm channels the cantilever ended beams-here shownas of I-beam form appears. also in Figures 2 and 3,.

where thebrackets '23 are riveted respectively to the channels and to the I'-beam, rivetingagalnbeing considered-as a desirable'form.

The structure shown in Figures 2 and 3 has been used by me before. However, in the present invention numerous improvements have been 3Otmade.

The cantilever. ends of the cantilever-ended beams form shelves and abutments for the transverse bandsfli The transverse bands form supports for suspended slabs which have main rein- 35.;f01cement only in the longitudinal direction, thus T aifordingi facilities for providing longitudinal slots in the fioorcoristructiona 'At the ends of 4 the cantilevers there are formed large and abrupt changes in thedepth ofconstruction which "with l gthe transverse bands form the equivalent of a hinge in the longitudinal direction of the construction. There is thus provided a safeguard against unknown and perhaps dangerous stresses that would be set up if changes in alignment ;.and: leveliare caused by unequal settlements in column footings or caused'by unequal compression in the supporting columns. Thereis'also provided at the ends of the cantilevers means of V adjustment'to bring the columns into true plumb .hnes.during constructio It has not been considered necess-ary'to'show' any fastening for thefloor slabwhich'maybe an integral part'of the entireunit as'in Figures 1 ply rest upon the cantilever and 2, or may sim ;beams or yard arms, and thus form'a suspension betweenthe a lever beams. 7

It has notbeen considered necessary to show support .for the ducts Which'may'be' suspended from the slab or may be separately supported in any manner which does not interferewith free ceiling space for the'floor'below.

The lateral ducts able manner with longitudinal ducts 28'extendting parallel with the cantilever be tween the adjoining beams of adjace The duct system as so far des by vertical ducts let, as the case and longitudinal ducts, Whichever may be connected, and a fan system by which inlet or outnt pairs. cribed is supplied 29 so as to provide inlet or outlet may be provided for the ducts as intended.

76 difference being made between to back, of transverse i fully encased in cased also in fire'rei.

diacent facing ends of thecanti- 21 are connected in any suitarms and be- 7 maybe, bttween the horizontal e case may be, no. them except as to .cation equipment.

are preferred;

ear-mac size or the special exigencies ofthey design planned. .Some of the space; provided. can be used for electrical conduits; water pipes,,etc-.x

One use intended for; the present construe! tion-amonga large number otuses'to which-it is suited.comprises'supply-of cold air. in conside able quantity, not forventilation aloneibut'for ventilation plus cooling ofaelectrioalccommuni In whatever use, the ducts may have the usual apertures or nozzles at thezsides, tops: on bottoms,

for distribution "of inlet air within the room; and this distribution may :be-ma'de at any height in any'of "the ducts as. desired; I Itihas' not zbee'nzcom sidered necessary to illustrate ..this"-'separately: as this feature iswell knownin theart'. I

-The cantilever-ended. beamst of: each off-the platforms terminate abruptlyat 25," 26 and-! and 26' inFiguresetofi, inclusive. :-'-:T G

In Figures .4 and 5. I- illustratereinforcingrods -30 parallel to the .lengthsof the'cantilever beams and reinforcing rods -3l.'-.transversel thereto. These figures differ only in; respect; to. whether the. longitudinal .ortransverse reinforcing is uppermost. In Figure: 4" the: longitudinal. rod-s -lie above the transverse. rods; and in-Figure 751th?) transverse" rods are: on 'topiofthe longitudinal rods. Long slots canbe-provid'ed parallelutosth'e reinforcing rods in whicheveridirec'tion theylie. Reinforcements may be .entir.ely diagonal. as shown by the rods 32 in Figure 6. Thediag'onal reinforcingmay also be employed; .with the lon'gitudinal andv transverse reinforcing as-shown in Figure 7; but the arrangements in Eiguresn and Figures 8, 9'and 10 illustratea construction in which threaded members are employed to adjust the positions of" the columnsa-nd beamsr' Suitable anchorages '33 are provided extendin in one direction and. suitable, anchorages 34 are extending in the direction' transverse thereto at: the end of each eanilever beam. .iThe 'ancho'rageshere take the form of a channel-whichihave openings 35 for threaded members 30 and 3l'whichare adjusted by nuts 35; as best 'seen'in-Figure 9i'- The adjustable construction asrshow-n' in "Figures 8to-10 is'prefer'red. 1 i Y 1 In all of the discussion of reinforcementpreceding. it isthe intentionxthat the enginer shall be free tofiuse any: reinforcement'whi ch is required.

I It will be evident that whatever form ofrein} foroement be used, adequate fire protection for the reinforcement will be provided. "1

Were referenceis; made in the claims t'o beams generally, without further explanation,- -it is the intention that the physicalbeam .used shall'be intended with or without encasement as may be required,

It will be evident that though the discussion in this case has includedprimarily encased structural metal beams; the same. features which make it desirable for structural metal encased beams, make the invention desirable also'for reinforced concrete beams of-whatever charactersince the same objections arise to ducts below th'e lcwr level of reinforced concrete beams'as arisefrom ducts below the encased structural metal'be'am's. It will be evident that ducts for airpassage,

for example, running inopposite. directionsdo not need to; pass each otherxbue'c'an' be con"- ;nected within the limitsrof the bottom ofthe beams and the bottom of the slab but-that; with conduits or difiercnt character such astwatenzand gas or water and: electricicabieithe conduits .inust -10 beifiattenedor otherwise adjusted one to another so as to permit them-topass.

it: will be,evident that even where full ad.- vantage. of my invention is not possible byreason'softhe fact that .aportion of the depth of a duct must project belowth beams, even partial. projection of; theduct height into the gap 'bEtWBQIIIhBybGfiHlS is correspondingly of value.

:Inview of. my invention and disclosure, variations and modifications to meet individual whim rinarticular .need will d ubtl ss becomecvident toothermskilledinthe art,v to obtain all or part ear-the benefits of-myinvention without copy.- ing'ithe structure-shown, andI, therefore, claim all such insofar as they sfall within thereasonable spirit andlscope of my claims.

Having thus; described my. invention whatd claimasznew. and desireto secure by Letters Pate 'ent is:

' 1. In-buildingconstruction, a seriesofparal-lel independent isolatedbuilding frames, each building ira-mecomprisin'g. a pair of columns, ;.yard arms extending transverselyof each columns-in both transversev directions and ending abruptly, and two longitudinal floor beams spaced away fromthe columns and-.rigidly-held' on either side. -of--the columnsa-t'the ends of'the yard arms, each floor beam consisting of a'center portion between the yard arms and free-ended cant-ilever portions extending beyond the yard "armsin each direction," the floor beams and yard arms forming in plan .a floor panelint'he form of-an elong'at'edH with two cross'bars, the'fioor beams terminating before adjacent floor panels are en countered in either the longitudinal or trans .verse horizontaldirection', there being wide open spaces'betwee'n the fioor panels i-n both longitudinal and-transverse directions which allow ventilatingducts and other equipment to completely encircle. each panel without interference by floor beams, the floor loads on the cantilever portions ofth floorbeains reducing the floor load-moments in the center portions, each floor panel" being continuous over only two columns andspacingthe columns of each pair from'one another. during -erection,'- and the building fraine's formed by the panels rigidly attached to the columns'throughthe yard arms resisting distor; tion fromhorizontal or longitudinal forces", and a floor slab supported on the floor panels and abovethelevel thereof spanning longitudinally from each cantilever portion of eachno r beam to' the adjoining cantilever portion of the ad}- ioiningfloor beam' ofthenxt floor panel, and spanningtransversely over the panel between the yard arms and over the'spaces between'ad jacent panelsf l 2. In building construction, a series or par-'- allel independent isolated building frames, each building frame comprising apair 'of columns yard arms extending transversely of each columnin" both transverse directions and ending abruptly, and two longitudinal floor beams spaced away from the columns and rigidly held on either yg-ated H with two cross bars, the floor beams terminating-before adjacent fl'oorpanels are encounteredinzeither the longitudinal or translverse. horizontal direction, there being wide open r ispacesr between: the floor panels in 'both longi tudinal and transverse directions which allow ventilating ducts and other equipment to completely encircle each panel withoutinterference by floor beams; the floor-loads on-the cantilever portions of the floor beams reducingthefloor load moments in the'center portions, each floor panel being continuous over only two columns and spacing the columns of each pair. from one another during erection, and the building'frames formed by the panels rigidly attached to the'c'olumns through the yard arms resisting'distortion from'horizontal or longitudinal forces, and-'aflooi' slab spanning longitudinally and transversely over each floor panel and two adjoining floor panels above the level thereof, the junctions between the floor slab andthe panels being characterized by abrupt changes of depth and stiifness factors resulting in elastic connections between the floor slab and each panel, providing elasticity ofaction between the adjacent building frames avoiding the indeterminate actionof continuous panel and girder construction over more than two supports.

3. In'building construction; a series of parallel independent isolated building frames, each building frame comprising a pairv of columns, yard arms extending transversely'of eachcolumn' in both transverse directions "and ending abruptly, and two longitudinal floor beams spaced away from the columns and rigidly held :on either side of the columns at the ends of the yard arms, each floor beam consisting of a center portion between the yard arms and-free-ezidd cantilever portions extending beyond the yardarms in eachdirection, the floor beams and yard arms forming in plan a floor panel in the form of an elongated H with two cross bars, the floor beams terminating before adjacent: floor panels are encountered in either the longitudinal or transverse horizontal direction, there being wide open spaces between the door panels inboth longitu- I dinal and transverse directions which allow ven- 12 the floor panels in botlilongitudinal and transverse directions which allow ventilating ducts and other equipment to completely encircle'each panel without interference by floor" beams, the floor loads on the cantilever portions of the floor beams reducing the floor load moments in the center portions, each floor'panel being continuous over only two' columns and spacing the columns of each pair from one anotherv during erection,

ftilever 'endsof one floor panel to the free cantilever ends of the nextfioor panel in a longitudinaldirection; the torsion resistance of the cantilever portions *of the fioorbea'ms resisting the transverse Z bendingzmoments in the slab-while tilating ducts and other equipment to'completely r encircle each panel without interference by floor beams, the floor loads on the cantilever portions 1 of the floor beams reducing the floor load'moments in the center portions, each floor panel being continuous over only two columns and spacing the columns of each pair from one another" during erection, and the building frames formed by the panels rigidly attached to the columns through theyard arms resisting distortion from horizontal or longitudinal forces, a floor slab supported on each elongated l-l-shaped floor panel abovethe level thereof and spanning between 1 adjacent floor panels, and ventilating ducts be-"'; low the floor slab and around the floor panels both longitudinally'and transversely.

, 4. In building construction, a series of parallel independent isolated building frames, each build-- I ing frame comprising a pair of columns, yard arms extending transversely of each column in both transverse directions and ending abruptly,

and two longitudinal fioor beams spaced away from the columns and rigidly held on either side of thecolumns at the ends of the yard arms, each floor beam consisting of a center portion between the yard arms and free-ended cantilever portions extending beyond the yard arms in each direction, the floor beams and yard arms formingin plan afioor panel in the form of an elongated H with two cross bars, the floor beams terminatingbefore adjacent floor panels are encountered in either the longitudinal or transverse horizontal direction. there being wide open spaces between the bending resistance in the longitudinal directionof-the'cantilever portion increases the resistance to the longitudinal bending moments in theiflat sl'a'b over the longitudinal space between thebeams;

*5; In building construction, a series of parallel independent isolated building frames, each building irame comprising a pair of "columns, yard arms extending transversely of each' column in bothtransverse directions and ending abruptly, andtwo longitudinal floor beams spaced away from the columns and rigidly held on either side o-the columns at the ends of'the yard arms, eachfioor'beam'consisting of a center portion betweenthe yardarms and free-ended cantilever portions "extending beyond the yard arms ineach directionythefloor beams and yard arms forming in plan a floor panel inthe form of an elongated Hwithtwo cross bars, the floor beams terminating before adjacent-floor panels are-encountered in either the longitudinal-or transverse horizontal direction, there being wide open spaces between the door panels in both longitudinal; and transverse directions which allow ventilating ducts and other equipment to completely encircle each panel without interference by floor beams; the floor'loads'on the cantilever portions of the floor beams reducing the floor load moments in the'center portions, each floor panel being continuous over only two columns and spacing the columns of each pair from one another duringerection, and the building frames formed by the panels rigidly attached to the columnsthrough the yard arms resisting distortion from; horizontal'or longitudinal forces, concrete encasement OfrthB-flOOI' panels, first reinforced concrete floor slabs extending over the spaces between the longitudinal floor beams of the floor panels above thelevel thereof and having integral connection of theconcrete with the concrete encasement of the'fioor panels, second reinforcedconcretefloor slabs at the same level v sand integral with the first, extending transverselyover the spaces-between the sides of the elongated -H-shaped floor panels and making in efl'ect elastic connections with the floor panels, having the main reinforcement extending transversely, and third reinforced concrete floor slabs ;at.i.thersame level as and integral with the first and second floor slabs, extending longitudinally over the spaces between the longitudinal ends of the floor panels, making in effect elastic joints with the floor panels and having the main reinforcement extending longitudinally.

6. In building construction, a series of parallel independent isolated building frames, each building frame comprising a pair of columns, yard arms extending transversely of each column in both transverse directions and ending abruptly, and two longitudinal floor beams spaced away from the columns and rigidly held on either side of the columns at the ends of the yard arms, each floor beam consisting of a center portion between the yard arms and free-ended cantilever portions extending beyond the yard arms in each direction, the floor beams and yard arms forming in plan a fioor panel in the form of an elongated H with two cross bars. the floor beams terminating before adjacent floor panels are encountered in either the longitudinal or transverse horizontal direction, there being wide open spaces between the floor panels in both longitudinal and transverse, directions which allow ventilating ducts and other equipment to completely encircle each panel without interference by floor beams, the floor loads on the cantilever portions of the floor beams reducing the floor load moments in the center portions, each floor panel being continuous over only two columns and spacing the columns of each pair from one another during erection, and the building frames formed by the panels rigidly attached to the columns through the yard arms resisting distortion from horizontal or longitudinal forces, concrete encasement of the floor panels, adjustment bars connecting the floor panels with adjoining floor panels longitudinally and transversely above the level of the floor panels, and a reinforced concrete floor slab including the adjustment bars within the slab extending over the floor panels and having the concrete integral with the concrete encasement around the floor panels, spanning over the spaces both longitudinally and transversely between the floor panels and supported on the floor panels.

7. In building construction, a series of parallel independent isolated building frames, each building frame comprising a pair of columns, yard arms extending transversely of each column in both transverse directions and ending abruptly, and two longitudinal floor beams spaced away from the columns and rigidly held on either side of the columns at the ends of the yard arms, each floor beam consisting of a center portion between the yard arms and. free-ended cantilever portions extending beyond the yard arms in each direction, the floor beams and yard arms forming in plan a floor panel in the form of an elongated H with two cross bars, the floor beams terminating before adjacent floor panels are encountered in either the longitudinal or transverse horizontal direction, there being wide open spaces between the floor panels in both longitudinal and transverse directions which allow ventilating ducts and other equipment to completely encircle each panel without interference by floor beams, the floor loads on the cantilever portions of the floor beams reducing the floor load moments in the center portions, each floor panel being continuous over only two columns and spacing the columns of each pair from one another during erection, and the building frames formed by the panels rigidly attached to the columns through the yard arms resisting distortion from horizontal or longitudinal forces, each column being continuous through at least two stories, and bending stresses transmitted to the columns at each floor panel through the yard arms being resisted by the strength of the column above a given floor panel and the strength of the column below the given floor panel.

8. In building construction, a reinforced concrete floor slab, a plurality of horizontal panels below and supporting the floor slab and each including transverse yard arms and longitudinal beams rigidly united to the yard arms near the ends of the yard arms andextending as cantilevers beyond the transverse supporting yard arms, and columns connected to and supporting the yard arms and each pair of columns with yard arms and beams forming a rigid frame capable of resisting horizontal forces, the floor loads on the cantilever portions of the beams reducing the bending moments in the portions of the beams spanning between the yard arms, the cantilever portions forming shelves and abutments for carrying the reinforced concrete slab which extends transversely between the panels, the

yard arms and beams projecting below the bottom of the slab, but having wide open spaces between the ends of the cantilever-ended beams of successive platforms forming a discontinuous construction so that slight settlement or compression of one of the supporting columns will not cause unknown stresses in the construction and the spaces between the cantilever ends of the beams below the bottom of the slab providing transverse channels in which ducts can be installed without projecting below the bottoms of the beams, the spaces between. the sides of the cantilever-ended beams of successive panels providing longitudinal channels in which ducts can also be installed without projecting below the bottoms of the beams.

9. In building construction, a plurality of sets of parallel spaced columns, yard arms rigidly attached to and extending transversely from said columns, generally parallel spaced floor beams between the ends of the yard arms with extensions, cantilever fashion, beyond the ends of the yard arms stopping abruptly short of the ends of adjacent floor beams, there being wide open gaps in the longitudinal direction connecting with wide open transverse spaces between the parallel cantilever-ended floor beams thus allowing ventilating ducts and other equipment to extend longi tudinally and to connect with ducts or equipment extending transversely Without interference by floor beams or girders and a reinforced concrete floor slab extending above the yard arms and floor beams, tied in therewith and extending over the transverse and longitudinal spaces between the floor beams and supported by the floor beams.

FRANK N. KNEAS.

REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS France 1924