July 18, 2024

Pratt Truss : All You Need to Know


In this article, we are going to talk about the pratt type truss, pratt truss bridge, pratt trusses bridge advantages and disadvantages, and warren truss vs Pratt truss.

A pratt truss is one of the oldest types of truss that has been used since the past as one of the most effective types of truss. The vertical members of this truss are in compression, while the diagonal members of the pratt designed truss are in tension. This helps in the simplification and production of an even more efficient design since the steel that is present in the diagonal members, which are in tension can be reduced. This causes a cost in the reduction of the structure due to, now, the presence of more efficient members, and this also reduced the self-weight. This also causes an ease in the constructability of the structure.

Pratt type truss is more suitable and appropriate for spans that are horizontal and here, the force is predominantly present in the vertical direction.

Now, let us take a look at the advantages and disadvantages of the pratt type trusses.

pratt truss explained

Advantages And Disadvantages Of Pratt Truss

The following are the advantages and disadvantages of the pratt type truss.

Advantages Of Pratt Truss

  1. The design of the pratt type truss is simple and well-accepted all over the world
  2. The design of the pratt designed truss bridge is aware of the behavior of all the members that are a part of the truss
  3. The structure of the pratt trusses bridge is cost-efficient and can be easily constructed by unskilled labor. It is extremely easy to transport and has a low initial cost
  4. The behavior of the members of the truss can be easily identified as the structure is super simple. Low-cost, simple analysis tools can be used in order to do a warren truss analysis.
  5. This bridge is ideal for places where traffic is heavy like railroads as this bridge is extremely straight and smooth

Disadvantages Of Pratt Russ

  1. The pratt designed truss bridge is not that big of an advantage if the load that is being put, is not vertical but is diagonal. Vertical and horizontal loads are in the need of varying consideration during designing.
  2. If the pratt type truss is not designed and constructed with care and supervision, it is susceptible to failure, which can cost you a lot more in the maintenance of the bridge.
  3. Pratt truss bridges are not efficient when it comes to long-span and shallow depth situations

pratt truss

Warren Truss Vs Pratt Truss

Even though extremely similar, there are a few differences between the Pratt truss and warren truss. Warren truss consists of isosceles as well as equilateral triangles. Pratt type truss consists of diagonal members that are slanted downwards towards the middle part of the bridge span. Warren truss is made out of heavier materials like heavier steel or iron. On the other hand, the pratt type truss is made up of thinner and lighter steel. And this is used to make the diagonal members of the pratt truss.

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