The present invention relates to short to medium span bridges across highways and other crossing requirements such as rivers, railroads, ravines, and wetlands. As designed, these bridges are totally prefabricated in the factory and preassembled to the greatest extent possible to ensure the proper fit of all of the elements which make up the completed bridge structure. This is done to speed up the erection time and to minimize or eliminate any costly and time consuming field labor.
There are many types of prefabricated bridges available from various manufacturers today. Most of these are used as temporary structures which can be erected quickly to be used while a permanent bridge structure is built and then disassembled and removed from the site. This extra work and time consumed is both costly and an inconvenience to the users of the bridge structure. The truss designs of these temporary bridges are not particularly appealing and the loads they are capable of supporting are generally less than that which is required for a permanent bridge structure.
It is therefore an object of this invention to provide a prefabricated bridge structure which can support the heaviest traffic loads that are required.
It is another object of this invention to provide a prefabricated bridge structure which can be assembled at the bridge site quickly, with a minimum number of elements which have been previously assembled where manufactured and then disassembled and shipped to the permanent site for rapid assembly into the finished bridge structure.
It is a further object of this invention to provide a prefabricated bridge structure that will last for a long period of time without being affected by weather or temperature conditions and require a minimum of maintenance.
Yet another object of this invention is to limit the number of bolted members which are the primary cause of bridge failures due to the flexing of the attachment points of the members, when subjected to the varying and cyclical loading of these areas by the traffic moving across the structure.
It is also an object of this invention to design a bridge structure completely out of metal and other flexible materials which can yield and then return to their original position without cracking or becoming permanently deformed.
Still another object of this invention is to provide a structure that has no areas that are difficult to paint or maintain in order to limit the possibility of corrosion of the metal portions of the structure.
A further object of this invention is to protect the inaccessible interior areas of the bridge structure from corrosion by completely sealing those areas or filling them with foam to eliminate the entrance of oxygen in the air which is the primary cause of corrosion in these inaccessible metal areas.
An additional object of this invention is to provide a bridge structure in which all of the elements work together to give the finished structure the strength and rigidity to satisfy all of the conditions to which the bridge will be subjected.
Yet another object of this invention is to provide a bridge structure in which the bridge barriers work in composite with the deck and substructure to form the box girders necessary to support the imposed loads to which the bridge will be subjected.
There are many other objectives to which this invention can be applied such as erection and launching from one or both sides of the area that is to be crossed, combining bridge spans parallel to one another to provide additional lanes to create multiple lane two way traffic bridges, sequential launching of bridge segments from portions of the structure that have already been erected to build long causeways over swampy or shallow water areas where there might be difficulty in placing or supporting heavy construction equipment, and many others that are too numerous to mention.
The bridge of this invention includes girders composed of upper and lower girder chords connected together by side plates and diaphragms to form a boxed girder with its upper portion shaped like a partially sloped highway barrier. Deck support beams are attached between the lower chords of the girders to support the orthotropic deck panels, which are fastened to the top of the cross beams. The orthotropic deck panels form a bridge deck made of steel or aluminum plates supported by ribs, such as undulating arcuate ribs, underneath. The panels are also attached to the lower portion of the barrier shaped inner panels of the girders. These orthotropic deck panels become the riding surface of the bridge and serve as a horizontal diaphragm to accommodate the horizontal forces to which the bridge will be subjected. The lower portion of the inner barrier panel can be made out of stainless steel to avoid corrosion in this area due to the scraping of the painted surface by snowplows and the wheels of vehicles which rub against these areas. From a practical point of view, this bridge design is best suited for two or three lane traffic. If more than two or three traffic lanes are required, a center divider girder can be made with both upper adjacent sides having the shape of a highway barrier. This enables the doubling of the width of the bridge and provide a separation for the traffic which is moving in opposite directions. The orthotropic panels have a temporary riding surface applied in the place where they are manufactured, which becomes the base on which the permanent macadam riding surface is applied in the field when all of the work is completed.
To summarize, the bridge is made of two side girders made up of upper and lower chords, which have stiffeners and diaphragms welded between them. Plate metal skins are fastened to the girders to form a box girder, the upper portion of which is in the shape of a highway barrier having sloped lower mid portion, forming a trapezoid when viewed in cross section, attached to a vertical upper portion, forming a rectangle when viewed in cross section. The metal may be steel, carbon steel, aluminum or other suitable materials. Cross beams are attached to web stiffeners which are fastened between the flanges and web of the lower girder chords and protrude through the inside cover plate of the lower chord to provide a connection point for the cross beams. Orthotropic deck panels are placed on top of these cross beams and fastened to the cross beams and to an angle which is welded to the upper portion of the lower inside girder chord cover panel and to each other to create a continuous horizontal diaphragm which is also connected to the girder.
The structure thus created essentially becomes a horizontal beam with the girders acting as flanges and the deck acting as the web. The girders, which are connected together by the orthotropic deck, have the weight carrying capacity to accommodate the vehicular traffic that will be traveling across the bridge.
In the case where longer spans are required, which requires deeper side girders, reinforced openings can be cut into the web of the upper girder top chord and the inner and outer skins above the level of the highway barrier to create a less confining atmosphere for the drivers and occupants of the vehicles using the bridge.
The present invention can best be understood in conjunction with the accompanying drawings. It should be noted that the invention is not limited to the precise embodiments shown on the drawings, in which:
In the foregoing description, certain terms and visual depictions are used to illustrate the preferred embodiment. However, no unnecessary limitations are to be construed by the terms used or illustrations depicted, beyond what is shown in the prior art, since the terms and illustrations are exemplary only, and are not meant to limit the scope of the present invention.
It is further known that other modifications may be made to the present invention, without departing the scope of the invention, as noted in the appended Claims.
This application is based upon provisional application No. 60/995,548, filed Sep. 27, 2007, which application is incorporated by reference herein. Applicant claims benefit under 35 U.S.C. §119(e) therefrom.
Number | Name | Date | Kind |
---|---|---|---|
60205 | Leopold | Dec 1866 | A |
795899 | Cunningham | Aug 1905 | A |
1984567 | Briggs | Dec 1934 | A |
2931467 | Fentiman | Mar 1963 | A |
3157731 | Torr | Nov 1964 | A |
3192669 | Hawkins | Jul 1965 | A |
3691576 | Miles et al. | Sep 1972 | A |
3789687 | Cutter | Feb 1974 | A |
4300320 | Rooney | Nov 1981 | A |
4353662 | DuChateau | Oct 1982 | A |
4355918 | Van Vliet | Oct 1982 | A |
4604841 | Barnoff et al. | Aug 1986 | A |
4912795 | Johnson | Apr 1990 | A |
5487199 | Nelson | Jan 1996 | A |
6055693 | Lehr et al. | May 2000 | A |
6073293 | Ahlskog et al. | Jun 2000 | A |
6081955 | Dumlao et al. | Jul 2000 | A |
6308357 | Maier et al. | Oct 2001 | B1 |
6401286 | Brenn | Jun 2002 | B1 |
7069614 | Sivachenko et al. | Jul 2006 | B1 |
Number | Date | Country | |
---|---|---|---|
20100043153 A1 | Feb 2010 | US |
Number | Date | Country | |
---|---|---|---|
60995548 | Sep 2007 | US |