US311624A - werner - Google Patents

Description

(No Model.) 3 Sheets-Sheet 1.

E. A. WHEN-3R.`

BRIDGE.

No. 311,624. vPatented Feb. 3, 1885.`

WITNBSSES INVENTOR ATTORNEYS.

(No Model.) 3 Sheezs--Shees` 2.

E. A. WERNER.

BRIDGE.

No. 311,624. Patented Feb. 3,1885.

WTNESSS: l v INYENTRI L//U (A @MW BY Mgg ATTORNEYS'.

(No Model.)

E. A. WERNER.

BRIDGE.

No. 311,624. Patented Feb. A3, 1885.

INVENTR WITNESSES TTORNEYS.

N PETERS. Phulo-Lnhngmphw. Waxhmgwn. D. C.

iUNiTnn STATES PATENT @Erica i EMMERICHYA. WERNER, OF NEW YORK, N. Y.

BRIDGE.

SPECIFICATION forming part of Letters Patent No. 311,624, dated February 3, 1885.

4 Application tiled April 27, 1882. (No model.)

To all whom t may concern:

Be itknownthat l, EMMERICH A. WERNER, of the city, county, and State of New York, have invented certain new and useful Improvements in Bridges, ot'which the following is a full, clear, and exact description.

The object of my invention is to provide a new and improved girder by introducing a plain tension or compression chord with bowgirders.

Figures l and 2 are side' views of different forms of my improved bridge. Fig. 3 is a detail side view ofthe lower part of one of the bows ofmy improved girder. Fig. 4 is a crosssectional View of the same. Fig. 5 is a plan View ofthe same.

In bow-girders with joints at the top or crown and at the abutments athrust is eX- erted against the abutments, and it is well known that the chords of such bow-girders take up the horizontal thrust of the bow and the action of the bending forces or moments, whatever :may be the manner of loading or the kind of bracing used in the girder. lt is known that with moving loads the absolute value of the moments is, according to the position of the loads, alternately positive and negative; hence producing alternately tension and compression strains in the chords, so that in an ordinary bow-girder both chords must be constructed and adapted to resist compression as well as tension. The thrust of the bow is always a compression strain. I take this thrust out of the chords by certain members introduced in the bow-girder. The action of the thrust is thus eliminated from thefchords, and now it remains to overcome the alternate positive and negative strains in the chords. As is known, the bending forces or moments acting in the chords are represented by the vertical reaction of the abutment and the vertical action ofthe load, less the bending generated by the action of the horizontal thrust of the bow. It is evident that as long as the latter is less than the former the total action of the bending moments will be positive; hence I calculate the height of the bow at each point in such a manner that the action or bending moments ot' the horizontal thrust will always be smaller than the action of the moment of the vertical forces-the vertical reaction and loads.

In calculating the height of the bow at each point in such a manner as to have the bending moment arising from the horizontal thrust less than the moment of the vertical forces, the moments in each point of the girder are always positive, and the alternate positive and negative strains will be reduced to positive or tension or compression strains only. Thus, if I provide a separate strut or chord running from the abutment to the top and taking up the complete horizontal thrust of the bow, and constructed and calculated in the manner above described, the chords of my new girder will be entirely independent of the action of the thrust, and the moments acting upon them will always be positive-that is, the strains will at all times be tension and compression-and a plain tension eye-bar chord can be used in the new girder This involves the arrangement of the struts so that they shall form at the crown an angle, each strut shaped according to the form found by the above-mentioned calculation. Moreover, in the new girder the chords are entirely independent of the height of the crown of the bow above the abutments for one and the same kind of loading My invention relates only to the chords of bow-girders, and is entirely independent of the system of bracing or construction of the bracing, which may be of any desired kind.

In illustration, I have shown in Figs. 1, 2,

' and 3 my new girder comprising in each half a plain compression upper chord, b, a plain tension lower chord, a, and suitable bracing. A is a special strut extending from the crown- `joint to the abutment, andthe chords a b, with their bracing, are mounted thereon and connected thereto, so that the horizontal thrust of the girder is taken up wholly by the special strut A', and none is communicated to the chords.

ln the drawings the strut is placed midway between the two chords. It is scarcely necessary to say that it can be introduced in various other ways; also that the strut can coincide with one of the chords.

In a suspension-bridge, which is a reversed bow-girder, the methods given above can also be applied for calculation.

The characteristic features of my girder are always that the moments in any part of the ICO girder are always positive, whatever may be the position of the load, and the absolute value of the moments is independent ofthe height ofthe crown-joint above the abutments for one and the same kind of loading.

Having thus described luy-invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The combination, in a boW-girder having Io joints atthe top and at the abutments, of a plain tension and a plain compression chord and a special strut in union with said chords, substantially as and for the purpose set forth.

2. In a bow-girder, the combination, with an upper plain compression-chord and a lower plain tensionchorcl united to each other by suitable trussing, of struts jointed together at the crown and jointed to the abutments, said chords and bracing being connected to said struts, as described, and suitable supports for the roadway, substantially as herein shown and i described, and for the purpose set forth.

8. In a bow-girder, the combination, with the two sections forming the bow, of struts jointed together at the crown and forming an angle, which struts are jointed to the abutments, and of suitable supports for the roadway, substantially .as herein shown and described, and for the purpose set forth.

4. In a bow-girder, the combination, with the two sections forming the bow, of curved struts jointed together at the crown and forming a Gothic arch, which struts arejointed to the abutments, and of suitable supports for and described, and for the purpose set forth;

EMMERIGII A. WERNER. Witnesses: v GEO. D. IVALKER,

C. SEDGFWICK.y

the roadway, substantially as herein shown 35

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