US371843A

US371843A - jackson

Info

Publication number: US371843A
Authority: US
Publication date: 1887-10-18
Anticipated expiration: 1904-10-18

Description

i Sheets-Sheet 1. P. H. JACKSON. BUILDING AND BRIDGE GONSTRUOTI Patented *y ot. 18, 1887.

N. Pneus. vlmmumumpw. wan-mm. nc,

(No Model.) 2 Sheets-Sheet 2IV l P. H. JACKSON. Y BUILDING AND BRIDGE GUNSTRUGTION.

Patented Oct. I8

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N. PETERS. PhowLnhogmpher. washingmn, C'4 C.

- Unirse raras PATENT FFlCEO PETER H. JACKSON, OF SAN FRANCISCO, CALORNIA.

BUILDING; .AND BRIDGE CONSTRUCTION.

SPECIFICATION orrning part Of Letters Patent No. 371,843, dated October 18, 1887.

Applmition iilrd January "l, i886.

Serial No. 157,930. (No model.)

- the city and county of San Francisco, and

vIO

State of California, have invented an Improvement in Building and Bridge Construction; and I hereby declare the following to be a full, clear, and exact description thereof, sufficient to enable any person skilled in the art to which my invention belongs to make and use the same, reference being had to the accompanying drawings, forming part of this specification.

This Ainvention relates to'girders, bridges, buildings, sidewalks having vaults or chambers vbeneath them, Sie.

The object is to strengthen bridges, buildings, Ste., in the construction of which concrete, artificial stone. brick.l anf'icement or mortar, or similar materials, are largely employed, and at the same time employ a proportionally small quantity of metal, dispensing with the large and costlymctal beams and girders now employed, and thus decreasing materially the cost of construction, while increasing the strength and security of the structure.

With these objects in View my invention consists, broadly, in building into the lower part ofthe body of cement, artificial stone, or similar material, the part below the neutral line, which is subjected to tensile strain when the bridge, floor, orst'ructnre is loaded,asmall metallici-shaped beamer beams, cemented to l.the surrounding material, which beam makes up the-deficient tensile strength of the body in which it is embedded.

Furthermore, the invention consists in employing the materials of the construction or body to aid in its own support; furthermore, in means for sustaining the ends ofthe structures, as in bridges, iloors, sidewalks, roofs, and the like platforms-oi:- tnesc materials, Whether constructed in'whole or in divisions or sections, in iiat sections or in arches, cmploying the material of the platform or body to resist compressive force and the longitudinal supporting tie or ties resisting the tensile strain.

Furthermorethe invention consists in arranging the flanged metal ties in the lower part of the door, bridges, Ste., below its neutral line, parallel with one another and in the same horizontal plane, so that when a load rests on the body between two parallel flanged beams and the arch is thereby deflected the direction of thrust of the material will be against 'the facing sides of the said beams at an upward angle, (as indicated by the dotted lines and arrows in Figs, 10 and 11,) compared to the direction before deflection took plaee,and the upper flanges of the beams, beneath which the material rests, operate to hold the material between the beams and prevent it from slipping over or being forced over them; and, inall y, in securing to the small beams or to a [iat bar near each of its ends and above its neutral line upright resistance-plates, which, when the beam is embedded ,in the structure below the neutral line thereof, will resist the extension of the snrronmling material.

Bridges, floors, sidewalks, girders, and the like made of cement, arti iieial stone, concrete, or similar material possess the property of great resistance to compression or crushing, but are comparatively very weak in resisting tension or a force tending to separate or destroy the cohesion of the particles; and to furnish the required strength of this weak part to equalize the great compressive resisting property of the material above the neutral axis, I employ these small metallic ilanged beams, built in the weak part of the body, so,

that the structure may be oi" uniform strength in resisting tension and compression.

All structuressuch as sidewalks with vaults beneath them, floors with chambers below them, beams and girders, bridges, and the like-are subjected to transverse strain, caused by loads or weight on their tops, and have to .resist compression on their upper parts above the neutral line and tension below their neutral line, the line where these two forces of diametrieallyopposite character meet and neutralize each other lying half-way between the top and bottom of the body, and being herein denominated the neutral line.

In the accompanying drawings, in which like letters of reference indicate corresponding parts, Figures 1 and 2 are longitudinal vertical ofthe surrounding material.

sectional views illustrating the action of forces, and adapted in that respect to a. bridge, sidewalk, floor, beam, girder, or any such structure, resting on end supports and adapted to be loaded and subjected to transverse strain, Fig. 1 representing the structure when there is no load upon it, and Fig. 2 representing it deflected under the weight of the load L, the vertical imaginary lines cfcfin Fig. 1 being changed when the structure is deilected into radial lines, as shown in Fig. 2, .fr y in both views representing theneutral line,where the compressive and tensile forces neutralize each other. Fig. 3 is a longitudinal vertical sectional view of a bridge, sidewalk, girder, or like structure, resting on end supports, with a small metallic ianged beam built in longitudinally and cemented to the surrounding material below its neutral axis, acting as a resistant to the tensile strain. Fig. 4 is a crosssectional view of a structure similar to that shown in Fig. 3, showing the small metallic flanged beams embedded and cemented in a hat body of the cement or concrete or like material. Fig. 5 is a cross-sectional view showing the small flanged metallic beam embedded at the foot of an arch and cemented to the surrounding material. Fig. 6 is a longitudinal vertical sectional view of a bridge, sidewalk, girder, or such structure, resting on end supports and constructed in the usual manner, with a large metallic beam built in the material and adapted to carry the entire load by resisting both the compressive force and tensile strain. Fig. 7 is a cross-sectional view of a structure similar to that shown in Fig. 6, showing the large beam inclosed in a dat body Fig. 7"isacrosssectional view showing the large beam inclosed at the foot of an arch which it supports. Fig. 8 is a longitudinal vertical sectional view of a. bridge or like structure, showing a small beam or flat bar embedded .therein beneaththe neutral line of the structure, having fastened to it near each of its ends and above its neutral line a resistance-plate, d. Fig. 8 is an enlarged view of the right-hand portion of Fig. 8, showing more plainly one ol' the resistance-plates and the position and manner in which it is attached upon the beam orbar. Fig. 9 is a longitudinal vertical sectional view of a bridge or like structure of cement, artitlcial stone, or similar material, in which my small ianged beam is embedded below the neutral line x y, but not cemented to the surrounding material, the bridge being shown considerably deflected under the heavy load L, so that the beam a is shortened above its neutral line g h, shortening to the greatest extent at its top, while the structure is lengthened-'below its neutral line x y, this view illustrating the action of the two forces without the restraintof unity between the beam and structure. Figs. 'l0 and 11 are vertical crosssectional views of a bridge or other structure having my small metallic `illanged beams embedded and cemented-in the footings of the arches, vbelow the neutral lines of the arches and parallel to one another, the arches being shown dede( P:ed'by the f.; aight of loads L, and the directionof thrust against the facing sides of the beams of the arch on which the weight is resting being then at a slightly-upward anwhile the remainder is made in sections. Fig. 8

13 is a perspective view of a bridge, sidewalk, or like structure,resting on end supports and covering an open space or chamber, and con sisting of lat sectional arches having flanged metallic beams embedded in the supportingsections below their neutral line, and supported at their ends by longitudinal non-.embedded ties. Fi 14 is perspective view of a bridge, sidewalk, or like structure, resting on end supports and covering an open space beneath, and consisting of a body of cement, artificial stone, or the like, havinga flat'upper and dat lowersurface,having small flanged. metallic beams embedded in it below its neu'- tral line, the ends of t-hese embedded beams being supported on and secured to longitndix nal non-embedded ties.l

All structures-such assidewalks with vaults beneath them, iioors with chambers below them, and bridges, and also girders employed in such structures-are subject to transverse 'strain caused by loads on their top, and have to resist compression of their upper halves above their central neutralline and tension or strain below their neutral line or plane,the neutral line, which liesin the central horizontal plane of the body or structure, being the dividing linebetween the two opposing forces. In order to illustrate the action of these two opposing forces, I have shown in Fig. 1 a longitudinal vertical'sectie'ial view of abridge, sidewalk, or similar structure supported on end supports, as it appears before any weight or-load is rested upon it; and in Fig. 2 I have shown the same structure deflected bythe weight of a load, L, the imaginary vertical parallel lines e f e f in Fig. 1 being changed when the structure is deflected intoradial lines, as shown in Fig. 2, xyin both views rep- ICO IIO

gradually increases until the top surface is reached, where the compression is the greatest. The bottom,measured ovei` its length,has becomed 'lengthened and the top shortened. The cement, concrete, artificial stone, or similar material having great power of resisting compression, the part above the neutral line x 1/ will strongly resist the weight of the load from lessening the distance between theimagi: nary lines e e at the top of the structure, and the material unaide'd will thus in its upper part resist a heavy load; but having comparatively little power of' resisting strain or tension, and being thus weak below the neutral line am, it is evident that if the distance between theimaginary linesff is to be prevented from increasing under the weight of a load the strength of the structure should be computed in accord with its great power to resist zompression.

Girders, bridges, and similar structures are now constructed with large metallic beams extending in their vertical height nearly to the top of the girder or structure, and adapted to carry the entire load by resisting both the compressive force and the tensile strain. I greatly lessen the expense andat the same time add to the strength of the girder or structure by embedding in the lower part of the girder or structure b, below the neutral line thereof', a small I-shaped metallic beam or beams, a, of about onehalf the height of the large beam now employed, and consequently only about one-half as expensive. This beam is cemented in the material in which it is embedded, (by any suitable cement, or by the material itself when the latter is cement, provided itis of great adhering quality, hydraulic cement being` preferred,) which surrounds the beam and prevents the surrounding material slipping or sliding over it when the girder or structure is deflected by a weight, being thus practically integral with the body in which it is embedded. By this arrangement the small I-shaped beam p strengthens the girder or structure most effectively against strain or tension, as it is entirely below the neutral line of the body, and therefore its entire strength is utilized to resist the tensile strain. At the same time that part of the material above its neutral plane or line serves effectively to resist the compressive force, my improved construction' thus Vutilizingthe material of the body or structure itself to resist the compressive foreei'A small metallic Ishaped beam, as I have applied it, has al large surface for the material to adhere to, and is of a `form that with al comparatively small quantity offmetal strongly resists bending to afar greater extent than a beam of square, round, or iat crosssection could possibly do, if containing only the same amount of metal. These beams may have two or more fianges; but when formed with only one this is always on top, so that the material of the body can extend under the flange on each side of the beam.

When desired, resistance-plates d .may be bolted or otherwise rigidly secure positions to the beam, or to a flat b of its ends, as shown in Figs. 8 z sist in preventing the extension of the material b below its neut the beam was not cemented, or w; Without being cemented and wit sistance-plates, when the bridge was considerably deflected under z as L in 0,111@ learn would b above its neutral line g h to the tent at its top, while the structui ening below its neutral line my w01 the beam, as shown in Fig. 9,

beam, instead of strengthening th would, in fact, tend rather to we will be seen that the resistancewhen applied to a fiangeless uncel will strengthen thestrueture by the material from slipping over making the beam practically an i1 of the girder or structure.

When two or more of the smal embedded parallel to each other in ure below its neutral line, as sho` 10,11, 12, 13, and 14C, and a weigh! the structure between any of the deflects that arch or part of" the st direction of the thrust against the of the beams is changed to a sligl: angle, as indicated by the dotted l: rows in Figs. 10 and 11, thus th material under the taper flanges ol which ,fectively prevents the m: slipping over the beams. The beai be placed parallel to one another l integral or solid structure, as `sl1o 10 and 1l, the left-hand portion of Fig. 14, or may be embedded inl of the supporting-divisions of structure, as shown in the rigltshz of Figs. 12 and 13.

When, as in Figs. 12, 13, and 14 flanged beams embedded 'in the structure are supported at their e longitudinal ties d', to which the bolted, and the crowns of the arche structure is either whole or sectior nected and braced to the longit by the struts or braces b, e, T, an(l form 'the subjectmatter` of a separ: tion, and which I will not, therefo; here at length,) the tensile strain both in direct and cross direeti( cement, concrete, articial stone, cement or mortar,- lor -bother likt above t i neutral line, yresist the c force also both indireetwandcross Having thus described my invei I claim, and desire to secure by Letl 1s- 1. The combination, with a gir floor, or other body of cement, con ficial stone, or similar material, metallic Ishaped beam or beams e1 the lower part ofthe body below t line thereof to resist the tensile s tructnre is deflected by the Weight vnd thematerxii thrust against the mgesof a beam,to prevent the slipne material, substantiallyr as deombination, with a girder, bridge, her body ol cement, concrete, arti- 5, or similar material, of a small haped beam or beams embedded and n the lower part of the body below ,line thereof to resist the tensile when the structure is deflected by of a load and the material thrust l web and the 'flanges of a beam, to e slippage of the material, substanscribed.

:ombinatiom with a girder, bridge, her body oi'eement, concrete, artie, or similar material, of a flanged am or beams or flanged bar or bars upright'resistance-plate secured to a of its ends and embedded in the of the body below the neutral line ombination, with bridge, floor, or leture builtin arches and composed concrete, artificial stone, or similar i' lsmall flanged metallic beams emand cemented in the structure below the neutral line thereof and parallel to one anotherin a horizontal plane, and longitudinal non-embedded ties supporting and having secured to them the ends ol' said embedded ties.

6. The eombination,with abridge, sidewalk, iloor, or like structure composed of cement, concrete, or like material, and constructed in tlator arched sections or divisions, of small flanged metallic beams or bars having end resistance-plates embedded and cemented in the supporting-sections below the neutral line thereof, and the longitudinal non-embodded ties supporting and having secured to them the ends of said embedded ties.

PETER H. JACKSON.

Witnesses:

JAMES B. LANE, HENRY- HAUsTEIN,