Emergency Bridge Q345B steel quick launching delaunching by worker easy recycal transport
BAILEY SYSTEM
Bailey bridges are built on site from a pre-engineered system of ready-to-assemble components. Utilizing standardized prefabricated components, Bailey bridges can be built to match a wide range of vehicular bridging applications. Because of their excellent versatility and overall value, thousands of Bailey bridges have been installed throughout the world.
ADVANTAGES
It is easy to install. Each part of the Bailey bridge is a standard machine made piece and is interchangeable among spans. Inmost cases, no heavy equipment is required to assemble or launch a Bailey bridge; only basic pioneer skills and equipment are needed.
It is highly mobile. All parts of the bridge can be transported to and from the bridge site by 5-ton dump trucks and trailers.
It is versatile. Standard parts can be used to assemble seven standard truss designs for efficient single spans up to 210 feet long and to build panel crib piers sup porting longer bridges. With minor non standard modifications, the expedient uses of bridge parts are limited only by the user’s imagination.
CONSTRUCTION
Transverse floor beams, called transoms, are clamped to the bottom chords of the trusses and support stringers and decking. Sway braces between the girders provide horizontal bracing; rakers between the trusses and transoms keep the trusses upright; and bracing frames and tie plates between the trusses provide lateral bracing within each girder.
Main girders
The main girders on each side of the center line of the bridge can be assembled from a single truss or from two or three trusses side by side. For greater strength, a second story of panels can be added to the trusses. The upper stories are bolted to the top chord of the lower story. For greatest strength, a third story is added. A single-truss, double-or triple story bridge is never assembled because it would be unstable. All triple-story bridges with the deck in the bottom story are braced at the top by transoms and sway braces which are fastened to overhead-bracing supports bolted to the top chords.
Materials and Finishes
Most load-bearing components use low-alloy, high-tensile Q345B steel. Excellent corrosion resistance is achieved with an inorganic zinc silicate coating. Final color is lusterless light green. Hot dipped galvanized is also available.
Deck
The clear roadway between curbs, called rib bands, is 12 feet 6 inches wide. The transoms supporting the roadway are normally set on the bottom chords of the bottom story. Foot walks can be carried on the transoms outside of the main trusses on each side of the bridge.
Bearings
End posts pinned to the end of each truss sit on cylindrical bearings which rest on a steel base plate. On soft soil, timber grillage is used under the base plates to distribute the load. The bridge can be assembled between banks of different elevations, but the slope should not exceed 30 to 1.
Load and Spans
Load, Span, and Bridge Type |
|
Span(m) Load |
Automobile-10T |
Automobile-15T |
Automobile-20T |
Catapillar-50T |
Trailer-80T |
|
9 |
SS |
SS |
SS |
SS |
———— |
|
12 |
SS |
SS |
SS |
SS |
DS |
|
15 |
SS |
SS |
SSR |
SSR |
DS |
|
18 |
SS |
SSR |
DS |
DS |
DS |
|
21 |
SSR |
SSR |
DS |
DS |
DSR |
|
24 |
SSR |
DS |
DS |
DSR |
DSR |
|
27 |
SSR |
DSR |
DSR |
DSR |
DSR |
|
30 |
DS |
DSR |
DSR |
DSR |
TSR |
|
33 |
DSR |
DSR |
DSR |
DSR |
TSR |
|
36 |
DSR |
DSR |
DSR |
DSR |
TSR |
|
39 |
DSR |
DSR |
TSR |
TSR |
TDR |
|
42 |
DSR |
TSR |
TSR |
TSR |
TDR |
|
45 |
TSR |
TSR |
TDR |
TDR |
———— |
|
48 |
TSR |
DDR |
TDR |
TDR |
———— |
|
51 |
DDR |
DDR |
TDR |
TDR |
———— |
|
54 |
DDR |
DDR |
———— |
TDR |
———— |
|
57 |
DDR |
TDR |
———— |
TDR |
———— |
|
60 |
DDR |
TDR |
———— |
TDR |
———— |
|
63 |
TDR |
———— |
———— |
———— |
———— |
|
Note Bridge type is as follows:
"SS" indicates Single row Single storey;
"DS" indicates Double row Single storey;
"TS" indicates Triple row Single storey;
"DD" indicates Double row Double storey;
"TD" indicates Triple row Double storey;
"R" indicates Reinforced. |