US1256081A - Long-span cantaliver-bridge. - Google Patents

Description

C. A. P. TURNER.

LONG SPAN cANIALlvEB BRIDGE.

APPLICATION FILED DEC. 22. 1909. 1

Patented Feb. I2, 1918.

IZ jef/kw (C M m m IIMVIED STATE@ "PATENT CLAUDE A. P. TURNER, OF MINNEAPOLIS, MINNESOTA.

LONG-SPAN CANTALIVER-BRIDGE.

To all whom it may concern:

Be it known that I, CLAUDE A. P. TURNER, of Minneapolis, in the county of Hennepin and in the State of Minnesota, have invented `a certain new and useful Improvement in Long-Span Cantaliver-Bridges, and do hereby declare that the following is a full, clear,

and exact description thereof.

My invention more particularly relates to long span cantaliver bridges, and my object is to facilitate and reduce the cost of erection of such bridges, and to give them all required strength, and togthis end my invention consists in the features of construction substantially as hereinafter specified and claimed.

Referring to the accompanying drawings,

Figure l is a view in the nature of a diagram of enough of a cantaliver bridge to illustrate an embodiment of my invention;

Fig. l is a similar view illustrating the utilization of the first inclined main post in the work of erecting the river arm.

Fig. 2 is a side elevation of a portion of one of the main compression chord members constructed in accordance with my invention;

Fig. 3 a horizontal section on the line C-C of Fig. 2;

Fig. 4 a cross section on the line B B of Fig. 2; and

Fig. 5 a cross section on the line A A of Fig. 2.

In a cantaliver bridge, such as that at Quebec, having a span of eighteen hundred feet, a single intersection IVarren type of main members is most economical, because of the eXtreme height essential for moment over the piers and the economic reduction in depth of the truss as we approach the anchorage or proceed toward the center. I therefore use the single intersection 'Warren type of main member. The single intersection Warren type is, as shown in the drawings, one wherein the web consists of one series of triangles formed by the inclined bars extending between the upper and lower chords. In the embodiment of my invention illustrated in the drawings, the vertical post member l0 over the main pier 11 is trussed in dialnond shape, and from it extend the top chord 12 and the bottom chord 13 of the cantaliver arm. In putting up the first inclined main post or cantaliver member 1 2 (which in the case of the bridge shown is approximately two hundred and thirty feet Specification of Letters Patent. Patmltedl Feb, 12, 1918,

Application filed December 22, 1909.

Serial No. 534,534.

long), I tie it at mid-length to a strut 3 4, 4 3, this being done as the irst half, or the part 1 3 in the first inclined main post is erected. The use of this intermediate stay as a chord in erection contributes to the convenient putting up of the cantaliver arm. Vhen the point 7 or the second inclined main post in the span is reached, by the use of an intermediate tie 5 6, the erection of the structure beyond the point 7 is possible by putting up the member 7 6, then 8 6, 6 9 and 8 9, simultaneously. Beyond this point, the erection involves no special features.

The panels in the case of the bridge illus-- trated, will be between fifty and sixty feet, and the usual eye-bar top chord is supported at regular intervals by vertical members 14 that in the main carry merely the weight of the chord. rI`his type of construction has the advantage of making vary few main joints in connection with the bar chain, which is used throughout the top chord.

It will be perceived that the sub-bracing that connects the central portion ofthe web members forms therewith and with the bottom chord a complete cantaliver sub-truss. In the case of the bridge shown the vertical post member 10 is some 300 feet high and, therefore, of many tons in weight, that results in distorting effects and secondary strains resulting therefrom, during erection, that involve the members of the sub-truss and cause alterations of their relative positions that call for adjustment of the parts.

.By using the diamond shape truss for the vertical post member, I am able to accomplish such adjustment which may be done by the wedge device commonly employed in bridge work, and applied to the lower side members of the diamond truss.

As frequently built in the United States, heretofore, the huge members in compression for the bottom chord have been defective, the failure of the irst attempt to construct the eighteen hundred foot bridge at Quebec indeed being due to this, the chords in that case having been made up of channels with heavy verticals and light lacing. In the embodiment of my invention I prefer to employ a main compression chord member having all required strength, and yet convenient or easy of construction. Said member is of sectional make up and it comprises a plurality, preferably, but not necessarily, three longitudinally extending parallel webs 15 that at top land bottoin have heavy flanges 16, and which are'connecte'd at the top by a cover plate 17. f-Tostiiten .the webs at the center, I have a concentration of metal in the form of-longitudinally extending ribs 18, and at intervals of three Ato tfour times ithe depth of the? chord 4I 'connect the webs transversely withdiaphragms 19, and the central ribs 18 and the bottom iianges 16 are connectedtogether atwinteryvals between the diaphragms by transverse strut-forming barsjQO. Bythe construction described `andillustrated, .ample accessmay :be had tothe interior or inside to drive rivets to connect the webmembers, and the resultying structure, while much simplified,is one allot whose parts are rigid under compres- .-slon.

In F ig. .la the frstinclined main post12 .is shown as .suspending` a bridge member in .work off erecting the river arm.

s'.Cpnlelof..thlsapatentmay he obtained for 'iN/'haul claim-isf.-

'In a cantaliver span, the combination of the main pier, the vertical post Ymember 25 mountedthereomtlued in diamond shape, top and bottom chords extending outward .from said post, webbing connecting said' chords, including an inclined main post that .eXten'dsto the top chord, upward and out- 30 ward from the bottom chord, and a tie that extends from the vertical post truss at substantially midlength thereof to substantially micllength of said inclinedvmain post and vconstitutes theftension member of sub-truss 35 .whose compression member is the bottom rWitnesses .GEORGE QDLUM. 'JAL'.LES 'COMM ve cents ealnby addressing vche Commissioner ofPatents, .Wehlnswn D- C

Images