Precision Brass Art Work proudly present you

1929 Pratt Truss Bridge

This is one of the most widely used American prototype truss bridge.  The truss bridge is a simple skeletal structure. In design theory, the individual members of a simple truss are only subject to tension and compression forces and not bending forces. Thus, for the most part, all beams in a truss bridge are straight. Trusses are comprised of many small beams that together can support a large amount of weight and span great distances. In most cases the design, fabrication, and erection of trusses is relatively simple.

The Pratt truss is identified by its diagonal members which, except for the very end ones, all slant down and in toward the center of the span. Except for those diagonal members near the center, all the diagonal members are subject to tension forces only while the shorter vertical members handle the compressive forces. This allows for thinner diagonal members resulting in a more economic design. However, once assembled trusses take up a greater amount of space and, in more complex structures, can serve as a great railway facility to trains.

Patented by Caleb and Thomas Pratt in 1844, this was among the most common American bridge types for the ensuing decades and was built in both wood and metal. There are many variations on the basic Pratt truss.

 

Glossary

  • abutments: heavy supports at the ends of a bridge, which transfer the thrust from an arch or strut to the bedrock or earth below
  • beam: a horizontal structural element spanning two supports
  • compression: the “pushing” force
  • deck: the bridge surface on which traffic moves
  • girder: a large beam, usually created by bolting or welding together steel plates
    pier: a heavy column or pillar which holds up a bridge
    tension: the “pulling” or “stretching” force

23-Feet Long Brass Pin-connected Bridge (Silver Version/Unpainted)

HO 1:87

100% handcrafted by brass with full rivet detailing

With walkways and railings

1929 Portals / Niet vollständige Angaben

Cross Braces

Top Corner Box Girder

Cross Bearers

Stringers

Mono Filament

Diagonal Brace

Girders

Laced Top-Brace

Steel (brass) Strip Detail

Mounting Pads

Truss Bottom

THE  BRASS BRIDGE REPRESENTS A STEEL BOX-GIRDER CONSTRUCTION IN TRIANGULAR SECTIONS FOR MAXIMUM STRUCTURAL STRENGTH.

   The bridge is approx. 23 inches long and approx. 5 inches high.

Brand New In the Box

THE EFFECT OF SUCH A STRUCTURE ON A MODEL RAILROAD PROVIDES A MEASURE OF REALISM THAT DEFIES IMAGINATION. ADD THIS TO YOUR PIKE TO CROSS THAT CHASM OR ALLOW A MAJOR CROSSOVER

You can choose color versions:

Silver or Unpainted