US1738614A - Reenforced-concrete structure - Google Patents

Description

Dec. l0, 1929. H. c. RlTcHlE y REENFORCED CONCRETE STRUCTURE 3 Sheets-Sheet Filed Jan. l2, 1926 Dec. 1o, 1929.

H. C. RITCHIE REENFORCED CONCRETE STRUCTURE Filed Jan. 12, 1926 3 sheets-sheet 2 Dec. 10, 1929. H. c. RlTcHlE REENFORCED CONCRETE STRUCTURE K ad [d 7 Patented Dec. 10, 1929 UNITEDgsrATs REENFORCED-CONCRET STRUCTURE Application filed January 12, 1926, Serial No. 80,775, and in Great Britain January 15, 1925.

This invention relates to improvements in reenforced concrete structures, and more particularly to such structures in which the metallic reenforcement itself forms a rigid self- 5 supporting structure adapted, to carry thel constructional loads including the load of wet concrete moulded in situ to form the composite structure.

In my said specification I have described a construction in which this diiculty is overcome by forming the longitudinal tensile reent'orcement entirely of round bars, embedded in the concrete, and connected to the other' or compressive reenforcement by transverse bracings and struts; the object of' the present invention is to employ as reenforcing members structural sections as I beams, or built-up lattice girders, adapted to form the self-supporting structure, and to strengthen them by a round bar or bars so disposed and connected to the two flanges or booms of the beam orl lattice that, in the composite structure, the tensile and compressive strength of the beam or lattice, the round bars, their connecting rods or stirru'ps and the concrete are, in accordance with the rules which obtain in standard practice utilized to the fullest-extent to meet the stresses to which the structure is subjected.

According to the present invention I form the rigid self-supporting structure of a structural section beam or built-up lattice, and I strengthen each of the main .longitudinal flanges or booms of the beam or lattice, which 5 is subject to tensile stress, by means of a longitudinal bar or bars embedded in the concrete on the side of the said flange or boom remote from the neutral axis, and I connect the bar or bars to the beam or lattice, and connect the flanges of the beam or lattice together by means of laterally disposed transverse stirrups or rods embedded in the concrete and l passing through the said flanges, said rods forming the necessary reenforcements. y

The respective stirrups or rods may embrace the respective bars and pass through and be fixed axially tothe two main longitudinal reenforcements, the said rods ork stirrups being embedded in the masses of concrete between the saidl reenforcements; or thebars of each group may, according to one modification, be connected together by means of pairs of saddles through which pass andI to which are attachedthe screw-threaded ends of the respective tra-nsverserods7 the saddles being clamped on the bars by nuts on the said ends. Vhen each of the flanges or booms of the beam or lattice is subjected to tensile stresses as in a column, arch, or beam'carrying a moving load, there is arranged in respect to each of the said flanges or booms a group of bars embedded in the concrete on the side vof the flange remote from the neutral axis, the groups ofV bars and said two flanges being connected together by laterally disposed transverse` stirrups or rods passing through the said flanges or booms and embedded in the concrete between them.

In the case of columns subjected to bending in two directions, one parallel with and the other at right angles to the plane of the web of the beam or lattice, the column is strengthened to resistthe latter bending action by means of two groups of bars respectively located in the concrete on the sides of the beam or lattice remote from the plane containing the neutral' axis and the said web.

The inventionI also comprises other Vimprovements as described and claimed herein. I have illustrated my invention inthe accompanying drawings in whichr:- Figs. 1 to 5 show the arrangement asapplied to the reenforcement of beams; v

Fig. ll being an elevation; Fig. 2 a-.corresponding transverse section; Fig. 3 a view similar to Fig. 2 showing a lattice structure; v v

Fig. 4 a View similar to Fig. 2 but showing three round bars. l

Fig. 5 a perspective View of a part of the g arrangement of Figs. land 2. y

Figs. 6 and 7 show'the invention applied to a column. Y

. Fig. 6 being an elevation, and

Fig. 7 atransverse'section.

S'which is a transverse section shows Vthe arrangement applied toa vertical coun-l terfort or buttress forV a wall, and Fig. 8A shows a modication of Fig. 8.

Figs. 9 and l() show the invention applied to the reenforcement of an arch.

Fig. 9 being an elevation.

Fig. l0 a longitudinal section. e

Figs. ll to'lwhichare fragmentary transverse sections, show arrangements for supporting the box in which the concrete is moulded. Y Y 1 In the drawings the concrete, indicatedfby ythe reference letter C, is added in. ythe usual..

manner to form the completed ystructure and is represented in the usualN conventional manner.- y

Referring first to Figs. l to 5 Figs. l and 2 represent the reenforcement of a beam comprising a steel girder of I- shaped section, which girder-O iscapable of carrying the constructional loads and wet concrete before referred to, but which without reenforcement is incapable ofkcarrying full normal load.

A Reenforcement is added in the form of longitudinal bars a placed as shown on the side of the tension flange'og remote from the neu- 25 tral axis; and transverse stirrups or reenforcement at right angles to the neutral axis 'p1 embracing the bars a', and passingl through holes provided in the flanges of tlie'beain O,

'and Vbeing hooked or otherwise 'secured at crete to completely surround the bars.

` The rods or bars a are bent up ats and hooked at their ends w, Fig.'1, asl required, in

1 oftliegirder O, but they may frequently kbe the ordinary mannerl of rod reenforcement,

, the lower' flanges o2 of the I-shaped section O being holed or notched as at 82,-. so that the said rods may pass up from below the said flanges in' an approximately vertical-.plane, Y

into the body of the concrete which is finally Aadded to complete the struct-ure; The hooked 'ends of theV bars 'a may be secured to the top flanges o1 of the I-section by means of split pins s1. 1 j j The stirrups p1 or the rods p2 embracing they bars a andrpassing through the flanges of the I-shaped section affordthe necessary mechanical bond between the flanges ofthe` said section and the concrete, and atthe same time connect the rod reenforcement .ato the said l-se'etion independently ofthe concrete.` The longitudinal spacing'ofthe stirrups or rods is'usually not greater than the depth more closely spaced so as tostifen the web of the said girderaud thereby increase the resistance to shear off the final reenforced con-` cretestructural member.

It will further be seen that the stirrups or rods p1 yor p2 pass through the flanges and the rectangular masses of concrete located between the flanges of the beam and thus 'prevent shear between thesaid masses of conecrete and the beam; the stirrups or rods thus arranged also act in conjunction with'the concrete tostiflenthe web of the beam.

ln 'Fig'. 3 the built-up'lattice girder T replaces the I-section shown in Figs. l and 2, the remainder of the reenforcement being similar to that shown` in' the latter figures. 'lhe stirrnps or saddles in this case areshown as rods p2 with eyed ends 71 and arev screwv-thi's'eaded at the top to take securingV nuts u.

ln the cioss-section,Fig.4, a beam O similar in construction to that shown in Fig. 2 is employed, but with three bars a added in-A stead of two. ln this case pairs of saddles 1 and b2 are used to hold thebars rigidly apart, and transverse members d similar to p2 pass through the holes in the saddles and holes inthe flanges of the I-section as shown, being anchored at top and bottom by means of nuts a and al, the saddles being tightened p p the bars by the tightening nuts 'Lal Fig. 5 is an isometric view on a larger scale,`

part of the reenforceinent of a beam such that shown in Figs. l and 2, both forms of stirrups p1 and p2 being shown. i

Y Figs. 6 and I'show one mode in which the invention may be applied to 'a column construction; in this case an I-shaped section steel stanchionl V capable of carrying the con struction loadsonly is reenforced by round bars; theV section of the stanclii'on V illustrated is assumed to be so loaded'that it does not needto be reenforcedto prevent bending in a direction parallel with the line m, my

should it need such` reenforcement only, roundbars would be fitted, arranged as shown inFigslto 5 but with the arrangement duplicated, that is to say with bars t arranged in respe tothe flange 01 (Fig. 2) inthe manner showninrespect to the'flangef 09?.; Such duplicate reeniorceinent is shown in F igs..8 i Y g iis to stiffeirtheV andv l0, hereinafter described.v

f rlhe bars al Figs. 6: and 7 column with reference to the neutral axis m5 are fitted on the sides ofthe Vstalnchiony remote from the saidV arie, and are connected tothe Yflanges v1 and e2 bymeans of saddlesfm,

which saddles arecaused to grip the bars and the lars nuts et? on the rods (Z. f

- fidditionaltransverse reenforcement ma beprovided'in the formlof stirrups or wire binders 11,', spaced' at suitable intervals vertically, and hired r'oundthel stanchions, which binders need Ynot nec'essarilyin this case be yconnected to the other parts'of the.v structure except by means of the" concrete which is finaliso flanges by means of'nuts u anda1 andv colly placed to complete the reenforcement of the column. f

The form of reenforcement illustrated in Figs. 8 and 10 and hereinafter described as applied to buttresses and arches respectively,

may also be employed in the case of columns ment bars at are added to both booms of theV rigid initial structure T provided to carry the constructional loads; Fig. 8A shows la similar construction except that as in the case of column or stanchion reenforcement additional bars b4 and stirrups or binders y1 may be employed with the concrete to complete the reenforcement of the final structure.

Figs. 9 and l0 show the invention as applied to the reinforcement of an arch.

The details of construction are similar to those already described for beam and buttress construction wherein reenf'orcemcnt Ybars 'a are added to both Ts t which form the top and bottom booms of the initial lattice steelworl; structure which is thus reenforced by the bars a, the stirrups or rods p, and the concrete which is finally placed to form the com-- plete reenforced structure required. Reenf`orcement as shown in Figs. 6 and 7 illustraty ing column construction may also bereinployed in arch construction. i

Fig. 11 illustrates how the temporary mould may be suspended from the fabricated reenforcement. In this figure strip metal hangers 1 of shape shown pass over and hang on to the lowest layer of bar reenforcement. These metal strips are bent at the ends 2, as shown, the ends being holed to take a nut vand bolt 3. The bolts 3 carry the bottom member 4 of the mould, which member in turn carries the side members 5, sheeting 6 being carried on transverse members 7 supported by cleats 8. Y Y

In Fig. 12 the transverse members d are provided with a threaded extension e below the eye i, (also shown to larger scale in Fig. 5). In this arrangement of the mould the bottom member 4 carries the side members 5 which are tied together at the top by cross members 9.

In Fig. 13 where the reenforcement is partly made up of a bar t, through the pins f1 are provided at suitable intervals and may be bent as shown. Where an I or other section with continuous web is employed the web is holed as required to pass the pins: f1. v

The centering or moulds for the concrete employed need not necessarily beof timber construction and any other or suitable material such as sheet steel or t-he like may be used. Further the centering Vof whateverlcharacter may be suspendedl in any conven- -ient manner from the rigid steel structure.

In the foregoing specification where round rods or bars are referred to, oval, polygonal or other similar section rods may be used, and where desired such rods maybe provided with projections, indentations or any other form of mechanical bond. p

Having noW fully described my invention, I declare that what I claim and desire to secure by Letters Patent is v 1. In combination in a composite structure of steel and concrete of the type herein referred to, a rigid self-supporting reenforcement comprising a main member, a longitudinal bar embedded in the concrete on the side of the main longitudinal tensile flange of said main member remote from the neutral axis of said main member to strengthen said tension flange, reenforcing means disposed at right angles to the neutral axis and passing through the flanges of said rmain member to a connect said bar to the main member and to connect the flanges of the main member to gether, substantially as described.v

2. In a structure constructed in accordance with claim 1, said reenforcing means being so disposed that the longitudinal bar isV embraced thereby, said means passing through both flanges of the main member, substantially as described.

V3. In a structure constructed in accordance with claim 1, a plurality of said longitudinal bars, pairs of saddles connecting the bars of a group, and respective reenforcing rods having screw threaded ends and passing through said saddles, said saddles being clamped on the bars and connected to said rods by nuts on said ends, substantially as described.

4. In a structure constructed in accordance with claim 1 in which each of the main flanges of the main member is subjected to tensile stress, a. group of bars disposed invrespect to each of saidflanges on the sides of the fiangesf` in two directions, one parallel with and the Y other at right angles to the plane'of the web ofthe main member, two groups of bars rer spectively disposed in the concrete at the sides of the main reenforcement remote from the plane containing the neutral axis and the said web, said bars reenforcing the main member to resist the latter bending action. Y

Y 6. In a structure constructed in acoord- Y ance' with claim 1, said longitudinal reenvforcing'bars being so disposed that Vthey are spaced apart a distance less'than thewidth ',4V e f 1,738,614

of thelange ofthe main members,said flange J having holes Vor notches through Which the bent ends ofthe sadbar pass into theconcrete on the side ofthe reenforced flange 5 nearest to the neutral axis, substantially .as

described.

In testimony whereof I set my hand.` v HARRY CLEMENT RITCHIE.

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