US1995585A - Reenforced concrete construction - Google Patents

Description

March 26, 1935. F. scHLAGlN-rwEl-r REENFORCED CONCRETE CONSTRUCTION` 2 Sheets-Sheet l Filed May l0, 1932 /NVE/V TR Filed May 10, 1952 2 Sheets-Sheet 2 F. SCHLAGINTWEIT REENFORCEDVCONGRETE CONSTRUCTION March 26,` 1935.

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,y n Mm .s NQ o e mm n@ Patented Mar. 26, 1935 Friedrich stiiiagintweit, Baden-Baden, Germany, Y assigner to'Rapag A.G., Haus Felsenau, Hergiswil a. See, Switzerland .Application May V10,1932, serial No. 610,429v In vGreat Britain July 7, 1931 The invention relates to reenforced; concrete floors or similar horizontal slab structures of the type in which a series of main reenforcedV concrete beams arecast above and/ or between lling members Ywhich themselves may 'be beams; to

. stituted by pre-cast reinforced concrete Vjoists placed parallel to them and supported by means of transverse or secondary. beams interconnecting the main'beams.. By this means the load onr the panels 'whichare formed by the lling joists is not transmitted `directly to the main beams, but indirectly bythe transverse secondary beams. With the use of transverse beams, arranged near the ends of the main beams supported by the Wall, a reduced bending moment is set up in the main beams.l f

An exceptionally simplel construction andplacing of the transverse beams is rendered possible according to the invention by thefact that each transverse beam is moulded between the front ends ofthe girders serving as illingsV which are to be supported, while the ends of the reenforce-l ments of these girders project into the'space serving `:for the accommodation of the .transverse beams; The-joists serving as llings accordingly come in contact at their front ends with the sides of the transverse joist and are rigidly connected with the latter. :Y 'Ina further development oftheinvention the' filling joists are so formed that they support one another laterally f throughout their lengthl and that the joist adjacent the main j oists serve simultaneously asfalsework for the main joists. Es-A r pecially suitableas fillings are pre-,cast reenforced concrete joists of I cross-section, the anges of vwhich are provided with rib-shaped projections serving for reciprocal support.

The construction of a door assembled accord# ing to this new system canbe carried out considerably moreY quickly andrnore vsimply than hitherto. The preferred method lof construction is such that the joists serving `as llillings .between the main joists are, during the construction of the transverse beams, supported by their ends on the temporary scaiolding `for the transverse beams. VApart from this temporary scaiolding which forms the lower mould .for the transverse beams, no other falsework whatsoever is required inthe construction of a floor. r

In the accompanying, drawings which illustrate the invention, l

l Fig. 1 represents a diagrammatic lView from below, and a cross-section parallel to one ofthe transverse beams, of the floor and the scaffoldl0 ing and vfalsework parts required for one construe# tion according to the invention.

Fig. 2 is across-section, on a larger scale, of the door parallel to the transverse joist, the falsework for the transverse joist being shownin side 15 elevation. f c I Fig. 3 shows a cross-section of the floor and of the falsework scaffolding, parallel to the main beams. Y

Fig. 4 is a diagrammaticview illustrating the 20 manner in which the main beams span from support to support, the ree'nforcement for these beams being shown in the upper part of this figure.

Fig. 5 `is adiagrammatic view showing the preferred arrangement of the lling joists and trans- 25 verse beams in relation to the whole span, the separate lling joists and their reenforcement being shown in the upper part of the ligure.

The floor illustrated consists of the longitudinal or main beams?) cast in situ at certain distances 30 kapart and supported on the wall a, filling joists c,

one transverse beam d and a continuous upper layer e of concrete or cement. The filling joists c consists of pre-cast reenforced concrete girders having a double-T-shaped cross-section, the lower 30 symmetricalanges of ,which vlie close together, while the upper angesvare each provided with a rib-shaped projection vc1 on one side for purposesrof reciprocal support. In the caseof the filling j oists c which bear against the main beams b.' the iange `half-sectionsr which face each other are omitted', so that thesejoists form the falsework forthe main beams b. B1, BZand B3 are the metal reenforcements for the'main' beams b. 'Ihe r tension and compression rods B1, B2 Vextend over 40 the entireleng'th of the main beams.

The sets of parallel lling joists c are arranged as shown in Figs. 1 andv 3 parallel to the' main beams b. These setsof lling joists c are arranged s'o that the space between the front sides facing each other'is suchas to enable the transverse beam d to be moulded between them. For the moulding ,of the transverse beams dall that is necessary is the lower falsework or centering S, which is carriedV by a scaffolding T, u1, u2, v.

On this falsework the ends of the girders c which face .each other are supported. Simultaneously the main beams b are also moulded in the channel-shaped spaces between the adjacent joists c. After the main beams and the transverse beams, and where necessaryvthe upper' concrete layer e, have set, the falsework together with the accessory scaffolding is removed. No additional falsework or scaffolding is required for the con` struction of the floor.

The tension and compression reenforcing rods C1, C2 of the filling joists c, are extended beyond the front ends of these girders facing each other,

. and the ends of these rods are bent so that they can be anchored in the transverse beam d.V

moulded between these front ends as shown in Fig. 3. D1 and D2 are the tensioning and compression reenforcingrods of the transverse beam d. Y 3 The joists c serving as fillings are supported at their outer ends'on the wall` a, as are also the main beams b. Y

Referring now to Figs. 4 and 5 of the drawings, the most economical arrangement -is one in which the centre span y of thefilling` joists is considerably greaterithan the end spans Suppose that w is the total load per foot length fora width of floor equal to the distance between successive main beams b. J- The load reaction P transmitted as a point load to each mainY beam by the transverse beams will be from the end filling joists and from the centre filling joists i; e.

and the maximum bending momentv on the main beam will be Par. i

If :1::1/4 and y=1/2,

Pps*

andthe maximum bending moment von the main Whereas with the usual construction Vthe maximum bending moment on the main beam will be WZZ.. 8

I claim:- I f 1. A reenforced concrete fioor structure consisting of a series of reenforced concrete'filling joists of I cross-section arranged parallel 11o-each other, pairs of said joists at intervals having faci filling j oists.

with ledges on which rest the flanges of adjacent beams so preventing relative vertical movement between one filling joist and its neighbour, pairs of said joists at intervals having facing upper fianges absent, reenforcement placed in the spaces so formed and concrete cast in `said spaces and above said filling joists.

3. A reenforcedconcrete floor structure com;- prising main reenforced concrete beams spanning ,from support, reenforced concrete lling joists of I-cross-section parallel to said main beams and constituting the formwork therefor, said filling joists being in three lengths across the whole span, spaces between the facing ends of said filling joists and two reenforced concrete transverse beams cast in said spaces interconnecting said main beams and transmitting thereto the load reaction from said filling 'joists.

,4. A reenforcedconcrete floor structure comprising main reenforced concrete beams spanning from support, reenforced concrete filling joists of I-cross-section parallel tosaid main beams and constituting the formwork therefor, said filling joists being in short lengths, spaces betweenthe facing ends of saidfilling joists, reenforcement projecting from the ends of said filling joists into said spaces andreenforced concrete transverse beams cast in said spaces interconnecting said mainvbeams and transmitting thereto the load reactions from said filling joists.

5. A reenforced concrete fioor structure comprising reenforced concrete filling joists of I cross section having the top flanges of facing joists absent at intervals, main reenforced concrete beams parallel to said filling joists and cast at intervals between pairs of said filling joists Y where said top flanges are absent, and transverse beams interconnecting said main beams and transmitting thereto the load reactions from said filling joists, said transverse beams being placed at distances apart greater than the distance of either of them from the main beam.

6. A reenforced concrete floor 4structure comprising reenforced concrete lling joists of I cross section having the top flanges of facing .l

joists absent at intervals, main reenforced concrete beams parallel to said filling joists and cast at intervals between pairs of said filling joists where said top flanges are absent, and two transverse beams interconnecting with said main beams at approximately 1A and 3A span and transmitting thereto the load reactions from said Y 7. A reenforced concrete floor structure comprising precast reenforced concrete filling joists of I cross-section with top flanges formed on one side with ledges on which rest the flanges of the adjacent `beams'so preventing relating vertical movement between one filling joist and its neighbor, said filling joists being formed at intervals with facing upper faces absent, main reenforced concrete beams parallel to said precast reenforced concrete filling joists of I cross-section and cast at intervals between said pairs of said precast reenforced concrete filling joists of I cross-section havingfacing upper flanges absent, and transverse beams interconnecting said main beams and transmitting thereto the load reactions from said precast reenforced concrete filling joists of I cross-section.

FRIEDRICH SCHLAGINTWEIT..

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