US2308334A - Bridge and analogous construction - Google Patents

Description

l. H. LUKE BRIDGE AND ANALOGOUS CONSTRUCTION Jan 12, 1943i.

2 Sheets-Sheet l Filed June 1v, 1940 EL '.j.

l INVENTOR. ffm/,fz H La@ W $4 a +A .n M d. f, A A .wf M. F 2 m n1 x Jan. 12, 143.V l. H. LUKE SBR-:DGE ND-ANALoGoUs CONSTRUCTION Filed June 17, 1940 v 2 sheets-Sheet 2 d./9 ke Patented Jan. 12, 1943 "UNITED STATES PATENT OFFICE BRIDGE AND ANALOGOUS CONSTRUCTION Irvin IV-I. Luke, Evanston, lll. Application June 17, 1940, Serial N0. 340,869

4 Claims.

the invention being to provide a construction ofthis kind aording comparatively increased strength, greater economy of -materials of construction, increased capacity to resist loads imposed thereupon and strains induced therein; moreover, render possible and practical, the usage of new and modern construction material, such as laminated woods, plywoods and kindred materials in its construction.

Equally important objects of my invention are to effect, in a construction embodying the same, great reduction in dead weight thereof without sacrificing rigidity and strength by the proper use of a skeleton structure in lieu of the wellknown and prevalently employed solid constructions; the construction of frames with a shallower crown and haunch depth, hence reducing the cost of building not only the frame structure per se, but also, the costs of foundations, footings, endwalls and wingwalls, and abutments, and reducing, to a great extent, the amount of excavating required for thelower roadway as well as for the structure proper, andV in those in stances where head room or clearance is a limiting factor, rendering a rigid frame design embodying the invention, advantageous and feasible where otherwise, it would be impractical or impossible to build.

Another object of my invention resides in the construction of a bridge including upper and lower roadways wherein the lower roadway structure serves in a dual capacity,ri. e., as a roadway and as a tie member to resist the tendency of the construction endwalls, legs and possibly footings, to move horizontally or substantially horizontally away from the roadway when the dead or live.loads ofthe bridge or structure are transmitted thereto.

Other objects of the invention will be in part obvious and in part pointed out hereinafter.

Structures of the rigid frame type have only been effectedV during recent years and usually, are of solid massive reinforced concrete construction. This solid type of rigid frame results in an ineiiicient use and waste of materials and places a tremendous burden of dead weight on the frame structure proper and on its footings.

In contra-distinction to types of thisvsort, my invention provides a skeleton construction of ribs, slabs, walls and beams placed and cast together monolithically where needed and only 5 where required to take the stresses and forces existing in the frame. Thus, due to the areas and sections of concrete eliminated, a great amount of weight is avoided by the improved bridgeA structure and by the same token, the

1Q incident costs thereof eliminated. A concrete bridge or structure spanning an' of the concrete section of the slab or beam itself,

from tensile steel to compressive face, resists shear or the tendency of the beam or slab to separate or slip along a longitudinal plane, or to crack diagonally or vertically on a plane normal to the beam. The teachings of my invention have to do with the elimination of the section of concrete not useful in carrying the compressive forces of the beam or slab and allowing only enough solid section to remain to properly resist the shearing stresses and to embed the tensile rods and to provide suiicient bond for the same as well as to cover and encase the rods used for extra shear resistance when such are required; and the particular method of framing,

monolithically or otherwise, by placing slabs,

beams and other sections with reinforcement to carry the stresses peculiar to the particular rigid frame comprehending my invention.

AIn, order. that the invention and its mode of operation may be vreadily understood bythose skilled in the art to which it appertains, I have in the accompanying drawings and the detailed description based thereupon, set out one embodiment of my invention.

.Inthese drawings:V

Figure l is a side elevation of theimproved bridge with the reinforcements of the beams, legs, footings and lower roadway ror deck schematically shown in association therewith, and

the adjacent earth lill shown in section.

Figure 2 is a vertical section through lthe bridge construction taken along the line 2 2 of Figure 5, looking in the direction in which the arrows point,'without showing the arrangement ofreinforcing means.

Figure 3 is a fragmentary vertical transverse section taken on line 3 3 of Figure 1, looking in the direction in which the arrows point.

Figure 4 is a similar section taken on the line 4 4 of Figure 1, looking in the direction in which the arrows point.

Figure 5 is a fragmentary view, partly in top plan and partly in section, taken on the line 5 5 of Figure 2, looking in the direction in which the arrows point, some of the reinforcing rods for the upper deck being schematically shown in association with said upper deck.

Figure 6 is a horizontal fragmentary section taken on the line 6 5 of Figure 1, looking in the direction in which the arrows point.

Figure 7 is a similar section taken on line 1 1 of Figure l, looking in the direction in which the' arrows point.

Figure 8 is a like section taken on the line 8 8 of Figure 1, looking in the direction in which the arrows point,` and also illustrating, in top view, a portionof the lower roadway or deck, certain of the reinforcing rods for the lower deck. and their arrangement with respect to the footing being schematically shown; and

Figure 9 is a detail section taken on the line 9 9 of Figure 2, looking in the direction in which the arrows point.

Having more particular reference to the drawings, in connection with which like characters of reference will designate corresponding parts throughout, the invention, when used for bridge, viaduct or similar construction comprises adeck or slab I adapted to directly receive and carry the paving of a roadway I'. Reinforcing means; such as rods 2 or the like, are 'preferably embedded or formed in the deck, enabling thesame to properly carry its loads or stresses to longitudinally disposed ribs 3, formed4 of concrete or other suitable material, arranged in substantially equispaced and parallel relationship. The deck I is constructed sufliciently thick to insure carrying of the roadway paving I' and other superimposed loads; moreover, it acts as the compression section of the ribs 3, i. e.,.in the central section of the deck, approximately in the region indicated at a. The` longitudinal spaced and relativelyparallel ribs 3 serve asl stiening members between the bridge endwalls 4 and their adjacent legs 5, and over across. the deck span, the ribs 3 also serve to resist shearing stresses, by virtue of their respective cross-sectional areas and with the assistance. of shearingrods 6, embedded or formed therein, which said shearing rods may beformed or bent from certain of the mid-span tension horizontal metal l, to be presently described, or from certainv of the haunch negative reinforcing metal 8also hereinafter described.` Other or additionalshearing rods 9 may also be provided in theribs 3.

Haunch thrustslabs I0, projecting towards each other from oppositefends of thebridge construction, particularly from theA opposed endwalls 4 thereof, are provided. These haunch thrust slabs I0, which are hereinv showed to be of concrete construction, are disposed? between the opposite end portions ofthe ribs 3 and are` carried by said endwalls 4 adjacent theirA upper extremities. They each serve to sustain the compressive forces of' the ribs 3 over and above the capacity ofthe lower sections of. each ofthe ribs. Suitable reinforcement is providedY in said haunch thrust slabs III whereby to render the induced in the haunch thrust slabs by the ribs 3, approximately in the region indicated at b, and by the same token, to effectually carry any other load which may be imposed thereupon. Also, it will be understood that the haunch thrust slabs reinforcing will assist to prevent shearing between the ribs 3 and said slabs I0.

Referring, particularly, to the endwalls 4 and the legs 5 adjacent thereto, it may be here noted that these elements function to support the entire dead andlive load of the bridge, viaduct or other structure, in its transmission to the footings II provided under each thereof. The hereinbefore referred to haunch reinforcing metal 8 within the legs 5, obviously serve to brace or reinforce the same and their adjacent end-walls 4. As will be noted, this reinforcing metal or rods 8 follow down through the backs or outer sides of eachof the legs 5 and are hooked into the respe'ctive'footings II. Such construction, in addition to serving as bracingor reinforcing means, also will function to effectually prevent horizontalmovement of` their respective endwalls 4 and legs 5 away fromthe lower roadway I6, which movement would otherwise beA apt. to` occur by reason of the application of forces to the end.- walls 4 and legs 5. If desired,.some of the reinforcing metals or haunohrods may bebent and disposed across the. legs 5 and thus, serve as shear reinforcements I2,V- similar to the shear reinforcements provided in. the ribs 3, as hereinbefore described. Moreover, if desired, other rods I4 may be utilizedin the legs 5 as shear` reinforcement.

The endwalls 4, as will be understood, each serve a similar purpose to the legs as. do the horizontal haunch thrustslabs I0 tothe ribs 3 and additionally, said`endwallsf4 afford effectual abutments for retaining the.. earth I5 of the usual ll. The endwalls 4 shalLbe properly'reinforced to resistthese forces coming upon the same.

Inasmuch. as. the endwalls. 4*; constitute. the` compression faces.of.the:legs.5 and have a compressive force in. the, approximate. regionA indi-- cated at c, or a reaction acting;in the. vertical direction whichY meets a horizontal force acting toward said endwallsv from. the; haunch. thrustl slabs I0, it. will bed seen. that; the. resultant of these two or` combined forces; isA anotherforce distributed from rib. 34 to'rib- 3 acting upwardlyV at an angle,` of approximately 45 in a' direction away from. the,` lower roadwayY IB: (hereinafter more fully describedl,4 This latterforce is resistedby haunch thrustsbeams II'which in turn,

are restrained by gaining support atl their ends.

because of, embedrnent thereofl in the adjacent ends of the ribs: 3 and the tops of theV 1egs5-v which, as willbe noted upon referenced-,o Figures 1 and 2,` join'- and are of substantially' the same width orv thicknessinthis'area. Thatis to say, the haunch thrust beamA I1, in each instance,

gains its support andrestraint in much the sameV manner as would. a .beam supported by looping hanger. rods` around'A each end thel hanger rods in this particular casel being the reinforcing` Reinforcing, in the form of' metall rods I8, is.

providedi'n each ofthehaunch. thrust beams. Il

same elli-cient t'o carry those forces.. which.. are. mand suchr reinforcing, is. sof designed. as. to carry forces coming thereonto from the haunch thrust slabs I and the endwalls 4 into the junction of the ribs 3, the legs and the haunch reinforce metal or rods 8. In order to resist shears, the beams I1 are provided with stirruplbars I9 to as'- sist the resistance of the concrete, if required.

Spanning the distance between the lower ends of the endwalls 4, and the legs 5 aswell as the respective footings II, and arranged below the upper span or deck I, is the lower deck or roadway slab I6, constructed of materials corresponding to that from which the deck I is constructed. Roadway tie-rods 20 are embedded in and disposed longitudinally in the lower roadway and have their opposite ends extended into and embedded and anchored, by hooks 20', in the oppositely disposed footings I I. It is of course understood, in this connection, that the opposite ends of the rods in the lower roadway I6 are arranged adjacent the relatively facing sides of the footings II in juxtaposed relation. Thus, inasmuch as all of the horizontal forces of the legs 5 or their tendencies to move away from the roadway are transmitted through said legs, and none, through the endwalls 4 unless they are properly designated and of a stiiness sufficient to take horizontal thrust, these horizontal forces are distributed from the bottoms of the legs 5 through the footings or beams I l to the roadway tie-rods 26 embedded in the lower deck or roadway I6 and anchored by the hooks 20 in said footings II.

At this point it may be noted that the footings I Il may be each provided with longitudinal reinforcement 2|, embedded therein and moreover, that said footings II, in addition to serving as anchoring media for the opposite ends of the lower deck or roadway I6, will also serve to properly distribute the vertical loads imparted thereto onto the soil or on the piles or caissons or other suitable supporting materials.

If under certain conditions, additional or subsequent bracing or rigidifying of the endwalls 4 and legs 5 should become necessary, I desire to have it understood that such may be effected by the installation of mud-jacks or other suitable or similar means whereby to raise and stress the lower roadway or deck IB to an extent suflicient to draw the endwalls 4 and the legs l5 to. gether or toward said lower roadway or deck I6, thus correcting settlement or other stresses and creating or recreating a proper stress in the haunch rods or reinforcing metals 8 and other members of the frame.

It is to be understood that my invention contemplates the usage of the frame without the lower roadway or deck I6 and its tie-rods 2l); such construction being eiected by designing the endwalls 4 of proper section and reinforcing them to restrain the passive and active pressure of the usual earth iill.

Manifestly, the construction shown is capable of further modification and such modification as is within the scope of my claims, I consider within the spirit of my invention.

I claim:

1. A bridge construction, comprising, in combination opposed endwalls, relatively spaced vertical legs adjacent the outer sides of and connected to said endwalls and extending throughout and above their respective heighths, footings arrangedV below and receiving and supporting said endwalls and legs thereupon, relatively spaced substantially parallel ribs spanning the distance between the endwalls, supported upon the same and the extended upper portions of said legs, and an upper deck received and supported on said ribs, endwalls and legs.

2. A bridge construction, comprising, in com bination opposed endwalls, spaced vertically disposed legs adjacent certain of the sides of said endwalls and connected thereto and extending to points above the same, footings below said endwalls and legs receiving and supporting the same thereupon, relatively spaced substantially parallel ribs spanning the distance between the endwalls supported upon the same and the extended upper portions of said legs, an upper deck received and supported on said ribs, endwalls and legs, and a lower deck between said footings and connected thereto.

3. A bridge construction, comprising, in combination opposed spaced endwalls, a plurality of relatively spaced vertically disposed legs adjacent the outer sides of said endwalls connected thereto throughout their respective heighths and extending above the same, relatively spaced ribs spanning the distance between the endwalls supported thereon and on said legs, a deck received and supported upon said ribs, horizontal thrust receiving means connected to portions of said ribs and to said endwalls, and an outwardly angled beam on each of the endwalls adjacent their jointures with the horizontal thrust receivingY means joined with adjacent portions of said ribs and with said endwalls, portions of said legs and with adjacent portions of said deck.

4. A bridge construction, comprising, in combination opposed and spaced endwalls, vertically disposed and relatively spaced legs integral with the outer sides of said endwalls throughout their respective heighths and extending thereabove, footings beneath said endwalls and legs receiving and supporting the same, a plurality of relatively spaced ribs spanning the distance between the endwalls received and supported upon the same and said legs, horizontal thrust receiving means connected to portions of said ribs Y and to said endwalls, an outwardly angled beam on each said endwalls adjacent their jointures with the horizontal thrust receiving means joined with said ribs and said legs, an upper deck received and supported upon lsaid ribs/connected at its opposite ends to the adjacent portions oi! said angled beams, and a lower deck between said footings and connected thereto. n

IRVIN H. LUKE.

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