US2636377A

US2636377A - Reinforced concrete beam

Info

Publication number: US2636377A
Application number: US627211A
Authority: US
Inventors: Hilpert Meier George
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-11-07
Filing date: 1945-11-07
Publication date: 1953-04-28
Anticipated expiration: 1970-04-28

Description

April 28, 1953 Filed Nov.

M..G. HILPERT REINFORCED CONCRETE BEAM fgajw: @B

nventor Gttomeg Patented Apr. 28, `1953 UNITED STATES PATENT OFFICE REINFORCED CONCRETE BEAM Meier George Hi1pert,.Bethlehem, Pa.

Application November 7, 1945, Serial No. 627,211

4 Claims.

. The invention relates to composite beams, panels thereof, columns in bending, and the like and has as an object an improvement in the structure of steel elements thereof by providing for the more economical and ready fabrication, and assembly thereof in position for the application of the concrete to complete the composite structure.

It is an object of the invention to provide a method of forming seats for reinforcement and shear rods for full diameter bearing and which may be embodied in a rolled or a built up steel tension member for beams, columns, panels, slabs, and the like.

It is a further object to provide a spring clip or the like for holding of said rods in steel against steel bearing in their seats.

It is a further object to provide an improved form of a spacing chair for holding temperature and additional reinforcement rods in proper position during concrete construction. For example, the improved form of spacing chair may be used during the pouring of the concrete slab of a composite member in beam or panel construction.

Further objects will appear from the following description when read in connection with the accompanying drawings showing illustrative embodiments of the invention and wherein- Figure 1 is a side elevation;

Fig. 2 is an end view of a plate illustrating one method of forming seats for rods;

Fig. 3 is a side elevation;

Fig. 4 is an end view of a similar method of forming seats in a beam structure;

Figs. 5, 6, '1 and 8 are detail vertical sections Y of diierent forms of inverted T beams combined with the reinforcement rods and concrete of composite constructions;

Fig. 9 is a detail side elevation of a seat for a square rod, the rod being shown in section;

Fig. 10 is a detail side elevation showing a rod in section with one form of spring clip for holding the rod to its seat;

Fig. 11 is a detail plan view of the structure of Fig. 10; v

Fig. 12 is a view similar to Fig. 10 showing aA different form of clip;

' Fig. 13 is a detail plan View of the structure Fig. 12;

' Fig. 14 is a side elevation of the clip of Figs. 12 and 13 as seen from the left in those figures; Fig. 15 is a detail side elevation of a form of chair;

Fig. 16 is a detail plan view of the structure of Fig. 15;

' Fig. 17 is a detail vertical section to an enlarged scale of upper portion of Fig. 8 showing a chair as of Figs. 15 and 16 supporting temperature and upper reinforcing rods, and form work supported from one iiange of the rod seating T member of the invention; and

Fig. 18 is a detail side elevation of the right half of a composite beam showing several features of the enlarged detail Fig. 1'I and the concrete slab combined therewith.

This invention relates to composite beams and panels thereof, having concrete or other plastic compression flanges in combination with steel webs and the necessary steel tension flanges'and its general object is to provide a novel means for the proper transferal of the stresses due to all beam loadings-dead, live, impact, traction, expansion, etc., as applied to said slab or compression iiange, thence to the steel web, which being integral with'the steel bottom iiange, completes the proper distribution of stresses for whatever loadings said beams, or panels thereof, have been designed. The application of the composite beam principle in engineering design has, in these United States of America, to date, been lacking in most fields of construction, and notably for highway and railroad bridges. This could be due to concentration of engineering research in the two separate fields, i. e. steel structures'and concrete structures, but there are many cases where the composite beam principle is indicated for economy and service. For example, in most building construction for girder beams, ller beams, joists, special T-beam joists', and rigid frame structures; in highway bridges fory simple beam spans, stringers, and floor beams; in railroad bridges with ballasted track for simple beam spans, stringers, and floor beams in certain special constructions; also in rigid frame bridges it may be applied for the horizontal and vertical legs. Many spans have been built with all the dead load carried by the steel beam, and the live plus impact loads carried by the resulting composite beam, but as the dead load moment is a large part of the total moment (about 50% for a 58 ft. beam span) such composite beam has not been designed for its maximum efficiency. In most cases where a concrete slab is required to distribute and carry loads to steel beams, practically all of the slab should be used with the steel beam to form a composite beam.

One very obvious reason for this limited use of the composite beam is the lack of a satisfactory and positive means of transferring the horizontal shears from the concrete to the steel beam. A normal bond exists between the steel and concrete when it first sets, but corrosion, impacts, and vibrations may break this bond, a fact which has been observed on bridges in use. While several types of shear connections have been used, such as clip angles riveted to the beam flange, bars Welded to the beam iiange, and certain proprietary types, etc., none have been generally accepted or standardized. The angles and bars fastened to the flange` d o not satisfactorily lock; the concrete to the steel beam vertically and' as soon as any separation occurs, the ei'uciency as a composite beam is reduced. To be completely satisfactory, the means used to transfer the hcri zontal shears should also rigidly and permanently lock the concrete to the steel even though shrink:-` age and temperature changes occur.. and. impact. on occasion is excessive.

A decided factor aiding in the efficient and economical use oi the composite beam principle is; welding. En the past. tel-1. yearsthe use of. welding-has extensively cha-.need steel construe-r tion in all branches, oi steel fabrication` except-- ing for highway and railroad bridges,1 where its, use is still negligible. By means of Welding, spe5 cial sections can ce formed for special conditions, flange sections varied as desired.,V and, in general any section can be. formed to utilize the, steel to its maximum strength. In this connection itis to be noted that composite construction reduces vibration in beams and girders^ For example, tests, show that composite. construction increased the4 resisting moment. o observed girders by 35 t0 510 per cent, while their resistance to vibrations Was increased from 250 to 300. per cent.

Any composite building project of' size requires a` considerable number of steel shapes, many duplicates. By constructing such shapes in thev manner shown and described herein, T members are made by splitting E beams or by assembling plates and thereby substantally any size and weight of steel member may be provided for the purpose, in accordance v-'ith the needs of the Work in hand.

To provide seats in the steel member ior the shearl and reinforcing rods to be embedded in the conc-rete slab ci a compositev member and in accordince with the invention, Besnaped open. ings. 29 are; punched in a plate as. shown in Figure I or in the. web of an i beam as shown in Figi 3 with the rounded parts 2i ci the p erforations of correct size to iit that size of rod refniired,v theV perforations being of such depth as to, provide for metal which may be removed in serering the. parts as indicated in dash line atV 22.

Ordinary rod seats. may also be, termed to proper depth ier such ordinary reinforcing bars,

as are not needed for shear. The plate or E beam is: then severed in. any usual mannen as lray-'burningtorch, along the line. 22- thus, giving twoduplie cate members The. spacing oi the perte-rations; 2dr and; 23. is. made at the locations in which Galc-ulations showthat rcds both for shear and ordi nary reinorcement shouldv be located ier the Work in hand.` One of the. thus provided T beams. may be used as such for a tension mein-- ber ci a composite beam asV indicated at` 2li in Fig. 5. with the necessary rods olaced i. the. seats as shear rods and/o1' ordinary reinforcing rods, or if standard rolled Is are deficient in depth of web and/or bearing for shear,I such` tension member may be provided by slitting a plate. such as shown inligure l which be welded at. 25 toA a T beam 23, to. be combined with the. slab Qt the concrete. as at. ci.l

If greater vertical loadings are to be met onehalf of a smaller I beam such as shown in Fig. 3 forming an auxiliary inverted T may be welded as at 28 to an inverted T beam 29 as shown in Fig. 7 and the rods may be placed in the seats provided by the perforations 2i) and 23 in the projecting web of this auxiliary T.

3 shows a form of built up T `beam comprising a danger plate 3Q anda web Piate 3| having an auxiliary T seat member 32 shown as onehalf of a beam of Fig. 3 welded to the top edge or the web plate 3i as at 34, which construction will; provide for any desired strength of composite beam.

The seats shown as for rounded rods at 20, Figs. 1. and 3. may hare, square portions if desired for the reception of square shear and/or reinforcing rods 35 as shown in Fig. 9.

In all cases the opening 35 to the seat is made of a. size to allow a rod to drop freely into position so that it may then be pushed into its-proper seat for full bearing and shear, as.. indicated. in Figs.. 9, 1,0, and, l2..

i-nids may be, secured in their seats. by driving; a steel; wedge` between, the rod a portion; ot the opening. however., when this practice. iS followed an undue strain is placed upon the. metal andy in the placingV of` the concrete. with the usual tamping Q13 vibrating, the Wedges are liable. to. displacementV leaving thebar without a metal-tof metal contact withy the; beam web.. To. avoid this. contingency and to hold the par resiliently inl constant contact with its seat and. such a. manner that it. cannot become, displaced by subsequent operations the invention provides o.. spring clip for the purpose.

as. shown in Fig., 11,l the spring clip comprises a, portion Si, to, contact, the, metal of the T beam. and, e pQrtion; 3ft-.having a rounded seat. 39. t0. bear. against the. bar with a Spring member Ml conf meeting the tivo parts. This Clin mail be con` tracted by applying pressure; upon the portion. 4.1. or by hammering and revolving the clip. into place.

from above in Fig.. 10.

in another form of clip, a. U. member 42. is pro. vided having legs 43 4.1i, with rounded recesses in their extremities as. at. 4.5,.. to. engage the. rod. and. with a beam web engaging portion litl united` to the legs by curved members.` 41 48,. This formof clip is applied to the beam in av position shown.

in dotted lines in Fig. 12,and by a. light flow of a hammer is forced to the, permanent,` position shown in Fig.

To prevent: displacement of said clip,Y a.. friction surfaceis provided as shown by' striking; out, portions 49. from thev metal of the plate portion 42 of the clip. It Will be seen that. the,- clipS; of, the. invention present their edges to the flow of concrete when applied.. and. thus the semi-.liquid concrete,- Will readily 110W thereabout with less danger of the. formation of. air. pockets.

To support temperature bars 50 and reinforcing bars 63.a,1`o rrn ci chair is. shown at 5| comprising a plate of metal recessed as at. 5.2 and having wings; 53, 54. struck out from the metal thereof adjacent the bight 5,5 of the chair.. The. recesses 52 may be formed by thev striking, out of the

ears

53, 54. This chair when placed. upon. the web 56 of the steel member will support. itselji in a vertical position for the easyplacingx of. the Spacing and/or temperature. rods. to,A be supported thereby in recesses 57 in its upper,` end., and thus only edges. of the chair are presented to the flow of the plastic concrete.

te. Since the. anses of` the auxiliaryl 1? support the slab and vertical loadings, they may be used to support the form work necessary for the placing of the slab, and arranged to allow of the easy removal of said form work and reuse by sacrificing only the bolt nuts embedded in the concrete.

In Fig. 17, there is shown a form joist 58 supported by bolts 59 from the anges of the superimposed auxiliary T 56 with form panels 69 supported on said joist.

Fig. 18 illustrates a composite beam tension member with its bottom ange as an inverted T 6| curved upwardly at its end with a web 62 welded to both its bottom ange and its auxiliary T, the upper edge of said auxiliary T being formed with bar seats in accordance with the invention.

It is well known to metal Workers that the punching out of material from the edge of a plate unavoidably results in a deformation of said edge, and produces a warp or camber of the plate. The method of rst punching and then parting of the punched member of this invention entirely avoids such distortions, and produces duplicate members.

The invention adapts itself to the formation of composite floors, slabs or panels such as shown in Figs. 35 to 38 in my Patent 2,271,592 dated February 3, 1942, and may be utilized in the building of walls, roofs and floors of buildings, and decks and oors of bridges, also in the supporting walls and decks of many constructions, e. g. viaducts, docks, mine works, ships and the like and when composite panels are preformed to proper size they may be designed to have ample strength for handling during erection. The metal-to-metal contact assured by the form of the seats and the use of the spring clips insures a full transference of stresses from the concrete through the bars by shearing strength to the steel web of the tension member.

It is obvious that the structure of the tension member of Fig. 7 could be produced by rolling a special shape comprising an I beam with a pair of spaced flanges or ribs near the longitudinal center line of the web, forming the punched B-shaped openings between these supplemental flanges or ribs, and parting the special shape through the punched openings in the manner described as applying to Figs. 3 and 4. It is also obvious that the shape shown in Figure 6 could be made by rolling. The welded shapes of Figures 6, 7, 8, 17 and 18 are regarded as integral shapes in the sense of the word integral as used in the following claims.

It is also obvious that the wings of the chair of Fig. 16 could be struck from the chair so as to lie on the face of the tension member edge opposite to their position shown in Fig. 16.

Minor changes may be made in the physical embodiments of the invention, within the scope of the following claims, without departing from the spirit of the invention.

I claim:

1. A composite beam structure comprising, in combination: a concrete compression ange; an inverted T-metal member comprising a tension flange and a web; an inverted and smaller continuous T-metal shape rigidly amxed to and aligned with the edge of said web opposite said tension flange, the free edge of the web of the T-metal shape being embedded in the material of the concrete flange, and said T-metal shape being provided with openings elongated in the direction of its length forming rod seats; shear reinforcing rods seated in said rod seats and embedded in said concrete ange; and means in said elongated openings holding said rods in contact with one edge cf said rod seats.

2. The structure of claim l wherein said means holding said rods in contact with said rod seats comprise resilient clips located in said elongated openings and means retaining said clips in said openings.

3. A beam structure comprising, in combination: a concrete compression flange; an inverted T-metal member below said compression flange comprising a tension ange and a web; a smaller continuous member having a horizontal portion rigidly aixed to and aligned with the edge of said web opposite said tension flange and also having a vertical portion extending from said horizontal portion, said vertical portion being embedded in the material of the concrete and having an upper edge including openings forming seats; elongated shear preventing and reinforcing members seated in said seats and embedded in said concrete flange; and means holding said elongated members in contact with said seats.

4. A beam structure comprising, in combination: concrete compression ilange; an inverted T-shaped metal portion comprising a lower tension ange and a vertical web; a substantially continuous member rigidly amxed to and aligned with the edge of said vertical web, said member being of greater width than the width of said web and being at least partially imbedded in said concrete flange, said member also being provided with openings elongated in the direction of its length and forming seats; elongated shear preventing and reinforcing members seated in said seats; and compressed resilient clips seated in said elongated openings, said clips engaging said elongated shear preventing and reinforcing members to hold said members in contact with said seats.

MEIER GEORGE HILPERT.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 582,386 Balph et al May 11, 1897 868,065 Barnes Oct. 15, 1907 1,017,118 Thomas Feb. 13, 1912 1,063,003 NeeVel July 22, 1913 y1,277,876 Detwiler Sept. 3, 1918 1,283,902 Hyatt et al Dec. 24, 1918 1,475,349 Marks Nov. 27, 1923 1,681,932 Ellison Aug. 28, 1928 1,936,147 Young Nov. 21, 1933 1,979,643 Sahlberg Nov. 6, 1934 2,016,616 Schaub Oct. 8, 1935 2,132,220 Powers Oct. 4, 1938 2,172,302 Tinnerrnan Sept. 5, 1939 2,271,592 Hilpert Feb. 3, 1942 2,340,176 Cueni Jan. 25, 1944 FOREIGN PATENTS Number Country Date 726,897 France Mar. 14, 1932 179,365 Switzerland Nov. 16, 1935 526,247 Great Britain Sept. 13, 1940