US539506A - Bridge - Google Patents

Description

2 Sheets-Sheet 2. W. N. CARR.

BRIDGE (No Model.)

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UNITED STATES PATENT Orric WILLIAM N. CARR, OF SUGAR TREE RIDGE, OHIO.

BRIDGE.

SPECIFICATION forming part of Letters Patent No. 539,506, dated May 21, 1895.

Application filed March 14, 1895.

To all whom it may concern: I

Be it known that I, WILLIAM N. CARR, a citizen of the United States, residing at Sugar Tree Ridge, in the county of Highland and State of Ohio, have invented a new and useful Bridge, of which the following is a specification.

This invention relates to that class of bridges which embody in their organization a combination of wood and iron, and which are designed for single spans of a hundred feet or less; and has for its object the construction of a bridge which will be capable of withstanding heavy loads, and in which the wooden portion of the chords will be protectedfrom the weather, and which will combine economy of construction and be durable and simple in its component parts.

The improvement consists, essentially, of the peculiar construction and disposition of the parts and the novel features which hereinafter will be more fully described and claimed, and which are shown in the accompanying drawings, in which Figure 1 is a side elevation of an end portion of a bridge constructed in accordance with and embodying the essence of the invention. Fig. 2 is a detail View of the upper portion of the end post, showing the manner of attaching the chord and diagonal truss-rod thereto. Fig. 3 is a front view of the parts shown in Fig. 2. Fig. etis adetail view showing the manner of attaching the struts to the chords. Fig. 5 isa detail View of the stirrup, showing the attachment therewith of the transverse floor-beam, the diagonal truss-rods, and the stringers or lower chords. Fig. 6 is afront view of the parts shown in Fig. 5. Fig. 7 is a detail View of the clip for the upper portion of the end stirrup. Fig.8 is an enlarged cross-section of a chord on theline X X of Fig. 1. Fig. 9 is a bottom plan view of a portion of the bridge, showing the manner of bracing the longitudinal floor-beams.

The numeral 1 represents the abutments upon which the bridge is mounted; 2, the end posts; 3, the struts; 4, thediagonal truss rods; 5, the upper chords; 6, the lower chords, or stringers; 7, the floor; 8, the longitudinal floor beams and 9 the hub-board. The chords 5 comprise a series. of wooden beams 10, which are placed together in a pile so as to .break direction.

Serial No. 541,770- (No model.)

tured to receive a vertical series of bolts 12.

Transverse bars 13, arranged on the under side of the pile of the wooden beams 10, have 1 their ends apertured forthe passage of corresponding bolts on opposite sides of the chord so as to connect them in pairs. By this means the wooden beams 10 are held in a compact mass so as to mutually strengthen and brace each other. The metal plate 11 serves to shed water, and also to brace the chord against lateral strain. The outer sides of the chord are protected by a covering of sheetrmetal 14, which is located between the bolts 12 and the opposing faces of the chord. This sheet metal covering 14 prevents the water soaking of the wooden beams 10, and is a protector against the weather.

The end posts 2 and the struts 3 may be formed of any desired pattern of beams or girders, metallic I-beams being preferable. These beams will be similarly formed at their ends so as to provide sufficient bearing su r face to attain the required purchase for the parts co-operating therewith. En-d plates 15 are secured to the extremities of the posts and struts by means of angle irons 16, which' are firmly bolted, to the web portion of the beams and have their horizontal portions bolted, or otherwise attached to the said plates 15. The end posts 2 are oppositely inclined so as to brace the structure in a longitudinal To attain the best results and prevent the posts 2 from being subjected to abnormal strain, it has been found desirable to slant the posts 2 on an angle of about two inches to the foot. This inclination of the posts 2 preserves the strength thereof, which is not the case with posts arranged at a greater angle.

The transverse floor beams 17 are attached to the lower ends of the struts 3 by bolts-18, which pass through the horizontal portions of the angle irons 16 and the plate 15 and have their lower ends connected by a yoke, or

plate, 19. A stirrup 2O straddles the end portion of the floor beam 17, and has its lower .end passed through the yoke 19, a similar yoke 21 being provided at its upper end above the beam 17. The closed end of the stirrup is composed of oppositely- inclined portions 22 and 23, theinclination of the part 23 being steeper than that of the part 22, thereby making one member of the stirrup longer than the other. This is shown most clearly in Fig. 5. The stringers, or lower chords, 6 have eyes to receive one member of the stirrup, and serve to hold the lower ends of the struts 3 in fixed relation. The outer ends of the extreme stringers, or chords, are threaded and passed through the end posts 2, and are provided with wedge-shaped washers 24 and nuts 25,

by means of which the desired linear tension is obtained upon the stringers, or lower chords, throughout their entire length. The extreme stringers occupy a relatively lower plane than the intermediate stringers, and the end diagonal truss rods 26 connect with the end stirrups at the angle formed between the opposite1y- inclined parts 22 and 23. By this disposition of the parts, the resultant strain on the stirrup 20 is neutralized, and the end beams 17 are prevented fromcanting, or turning from a vertical position. A clip 27 spans the upper end portion of the stirrup, and is adapted to hold the parts 26 and 6 in relative This is best seen in Fig. 6. The

position. open end of the clipis provided with a wedgeshaped yoke plate 28 and tension nuts 29.

The foregoing is a detailed description of the extreme stirrups to which the extreme, or outer, diagonal truss rods 26 connect, but the intermediate stirrups will be of the ordinary form, and the stringers, or lower chords, 6 will The ends of the extreme chords are pro:

tected by metal plates 31., which are held in position by the outer truss rods 26, which pass diagonally through the end portions of said chords and receive nuts 32 on their threaded extremities. These plates 31 incline and occupy a position substantially at right angles to the rods 26, and the extremities of the cap plate 11 project thereover so as to shed water. The lower side of the extreme chord is slightly inclined to receive the upper end of the post 2, so that the latter may obtain a firm bearing throughout the area of the plate 15.

The struts, as well as the longitudinal floor beams on opposite sides of the bridge, are strengthened and braced by diagonal truss rods 33, whichare similar in construction to the truss rods 4, except that they are apertured, or provided with eyesat each end to be slipped upon Suitable tension devices34 will be provided a member of" the stirrups 20.

for properly tensioning the said truss rods 33 in the construction of the bridge.

From the foregoing, it will be seen that the bridge involves a comparatively simple and compact arrangement of parts, and is strengthened and braced in every part, and that provision is had to obviate turning, or twisting, of the extreme floor beams, and that it can be erected on an economical basis consistent with the resultant advantages as compared with like structures.

Changes in the form, proportion, and the minor details of construction may be resorted to without departing from the principle or sacrificingany of the advantages of this invention.

It will be understoodthat in constructing bridges in accordance with the invention, a sufficient camber will be given thereto, the same as usually provided in bridges as generally constructed, the amount of the camber being dependent upon the length, or span, of the bridge and the judgment of the con- *structer, and about six inches in sixty foot spans.

Having thus described the invention, what is claimed as new is 1. In a bridge,the combination with the transverse floor beams, stringers, or chords, and a diagonal truss rod, of a stirrup having attachment with the aforesaid parts, and having its closed end formed of oppositely-inclined parts, the inclination of one part being greater than the other, and the diagonal truss rod seated in the angle formed between the said oppositely-inclined parts, substantially as described for the purpose set forth.

2. In a bridge, the combination with the transverse floor beams, stringers, or chords,

and a diagonal truss rod, of a stirrup having attachment with the said parts, and having its closed end formed of oppositely-inclined portions, the truss rod being seated in the angle formed between the said oppositely-inclined portions, and a clip embracing the upper end portion of the stirrup and adapted to hold the parts in fixed relation, substantially as set forth.

3. In a bridge, the combination with the transverse floor beams, stringers, or chords, and a diagonal truss rod, of a stirrup having attachment with the said parts, and having its closed end formed of oppositely-inclined portions, one of the said portions being of a greater inclination than the other, the diagonal truss rod being seated in the angle formed between the said oppositely-inclined portions, and a clip embracing the upper end portion of the stirrup and serving to hold the truss rod to its seat and the stringer, or chord, on

the member corresponding with the lesser inclined portionat a higher level than the chord attached to the opposite member, substantially as described for the purpose set forth. 4:. The herein shown and described bridge,

' the end portions of the floor beams, and having positive attachment with the lower ends of the struts, the closed ends of the extreme stirrups having oppositely-inclined parts, one part being of greater inclination than the other, clips applied to said end stirrups, di-

agonal truss rods, and stringers, or lower chords, the extreme diagonal rods being seated in the angle formed between the oppositelyinclined parts of the end stirrups, and the 0pposing ends of the stringers, or chords, having attachment with the said end stirrups, occurring in different planes, substantially as described for the purpose set forth.

In testimony that I claim the foregoing as my own I have hereto aftixed my signature in the presence of two witnesses.

WILLIAM N. CARR. Witnesses:

JAMEs E. LONG, E. O. HETHERINGTON.

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