US954750A - Reinforced-concrete bridge. - Google Patents

Description

I 'J. MANDEVILLB. REINFORCED CONCRETE BRIDGE. APPLICATION FILED PBB .15,1909.

Patented Apr. 12, 1910.

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JoHN E. MANDEVILLE, or HAWL Y, PENNSYLVANIA.

REINFORCED-CCNQRETE BRIDGE.

' of Hawle in the county of Wayne and State of ennsylvania, have invented cerin new and useful Improvements in Reinforced-Concrete Bridges, of .Which the fol lowing is a specification.

This invention relates to improvements in details of construction of-that class of concrete bridges in which metal tension members are used, commonly called reinforced concrete construction.

The invention will be described in connection with the accompanying drawing, in

which,

Figure 1 is a side elevation of a-concrete bridge partly in section, on the line 1'l of Fig. 3; Fig. 2 is a partial longitudinal vertical section on the line 22 of Fig. 3, and Fig. 3 is a vertical transverse section partly on the line 33 and partly on the line 3 3"- of Fi 1.

Reterring to the drawing, it will be seen that my improved bridge comprises a roadway 10 and girders 11 extending downwardly from the roadway, the roadway slab and girders being formed integral. The girders are in the form of ribs running longitudinally of the bridge from one of the abutments 12 to the other 13. The under surface 1a of the roadway or slab 10 between the ribs, is preferably slightly crowned excepting at the ends 15 where it is curved downwardly to meet the abutments, as shown by the dotted lines in Fig. l and shade lines in Fig. 3. At each side of the bridge and integral therewith, I preferably form a para-pet 16. As shown in the drawing, this parapet is about as large in cross section and height as one of the ribsll. Railings 17 may be secured to posts anchored in the parents if desired.

- I secure grsat-;- -strength and carryingpower in the bridge by embedding metal tension members 18 inthe ribs or girders 11.

' These tension members are quite close to the lower surfaces of the ribs at the middle of the span, and curve upwardly to their ends which are preferably located approximately in the lane of the slab or floor and at the rear 0 the abutments. The corresponding ends of the several tension rods 18 are passed through a common plate or beam 19, which as shown, is a channel bar. The ends of the I Specification of Letters Patent. Patented Apr. 12, 1910.

Application filed February 15, 1909. Serial No. 477,880.

rods are threaded and each end is preferablypro vided with two nuts 20, with which the rod can be tightened and locked. After the concrete has set the nuts 20 are turned until the tension rod is placed under considerable strain, which adds grdatly to the rigidity of. the structure and enables me to make a span, of maximum length for' the amount 'of ma:

terial used.

I preferably treat the parapet 16 as'a '5 girder and embed in it a tension rod 21,

similar to the rod 18, the rods 21 having plates 22 at their ends and having each end provided with adjusting and locking nuts 23 similar to the nuts 20. The nuts 23 are also turned. up tightly after the parapet proper,

has set and before the wing-walls 24 are con structed.

To prevent any longitudinal splitting or cracking of the roadway slab 10, I preferably embed therein a series of transverse rods 25 Whichare properly anchored at their ends in the parapets or side girders and I also provide'rods 26 which extend transversely of the bridge through the parapets, or girders, and the roadway slab, ty ing them all securely together.

I have found in actual practice that a bridge constructed according to the foregoing specification, is exceedingly strong considermg the amount and nature of material used and that such bridges are sufficiently cheap to be used on the lines of country roads and at other places where trafiic will not warrant the construction of expensive bridges.

It will be understood that the metal parts of my improved bridge are embedded and entirely covered and protected by concrete .when the bridge is finished, with the eXcep tion of the railings.

It will be seen that the roadway slab 10 forms a continuous compression member for the several ribs or girders ll andthat the anchor plates 19 for the tension members are in the plane of said slab. The anchor plates are therefore very securely spaced apart and a give the best possible support to the tension members 18, and these members in turn are so situated that they resist the tension in the lower edges of the girders. It will also be seen that the arched form of the roadway slab at its ends adds considerably to the strength and stiffness of the bridge.

'Having described 'my invention, What I claim and desire to seeureloy Letters Pat- .I I 1 "I I l. A reintorced concrete ormge CQlYlDllS- ing abutments e roadway slab extending}; be

tween the abutments and engirders e):- tendingbetween the ebutments on the under side of the roadway slab, said roadway slab,

ri'los and abutmentsbeing integral, niet'zal tension men'lbers e 'nbeddedin each rib,,sz1id members being located at the lower edges ol the ribs near the middle of the ln'idge and extending upwardly to the plane of the plates extending transversely of the bridge in the plane of "the reinilwey slab end through which the threaded ends'of i110. tension members extend, said nuts being adapt to bev turned up against tlie'zmcbor plates to tighten the tension members, and metal rods extending acrose the bridge and env bedded in the l'oadwey slab and ribs, said rods being anchored in the perzipets for the purposeset forth. i

2. A reinforced eonc ete bridge ,oompris ing abutments, a roadway slab ezi'tel'iding between-the abutmenls, parapet- Wulls at the sides of the bridge extending upwardly from the roadwe' slab, l ngitudinul gi'rdefl tending dovmwarely from the 1" "lab, the side girders being in l ice]. planes of t panqet 1s, said Jets and parapet Walls rnetiue of concrete tenttiDHiIDG-ZHTS slab being an integral E sion members extending; longitudinally through the girders, said men'ibei' being 10- 'cated near} the bottom ofthe gi middle of the bridge and wardly at each end, iilll e pluteszlt each end through. .JlilCll the ends of the tension meu'lbeis pas i mean beefing on the abutment plates for. ugliteni;ugtlie tension' llztilillHBLF, additional tension men'ibers arranged inthe parapet v- ,nieens for tightening said additional ill l after the eOnei ete in ii'liieln they ate einly i set,- and metal rods extending bridge at intervals, said i'odsbeing embed- (led in the fomflwuy slz'ib and attending into the girders substantially as deseiit'aed.

En 'testin'iony whereof 1 Still in signature in presence e'f two witnesses.

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