Pratt Roof Truss Design

Design hub pratt truss design in solidwork.

Pratt roof truss design.

The pratt truss design remained popular as bridge designers switched from wood to iron and from iron to steel. From above analysis and design of pratt truss following limit state method is more reliable and economical than the working stress method for designing roof trusses for the same configuration of truss total percentage saving in weight of steel is by limit state method is 23 as compare to working stress method. This particular type of truss offers some interesting features mainly thanks to the fact that the vertical members provide tension while the diagonal ones are bringing in compression. The consumption of steel is less in lsm with respect to wsm.

A way of making a larger truss out of pre fabricated elements of smaller trusses these roof trusses are simple in design but very effective and cheap to build. For the pratt truss and any of the types of truss mentioned below it is possible to provide either a single or a double slope to the upper chord of a roof supporting truss. Often seen in bridges it features several vertical chords that are connected by a diagonal chord. The pratt truss was patented in 1844 by two boston railway engineers caleb pratt and his son thomas willis pratt.

This chord runs from the top of one chord down to the bottom of the other chord. In this fashion they form a pattern of interconnected ns. It has a wide range of applications including being used as a wood truss calculator roof truss calculator roof rafter calculator scissor truss calculator or roof framing. An example of a double duo pitch pratt truss is shown below.

This particular 6 section structure has 21 truss members and 12 joints. Here is how it looks. Design hub pratt truss design in solidwork. Pratt truss this is one of the most popular steel roof truss types and it is quite economical.

American standard steel c channels dimensions and static parameters of. A roof truss based on two pratt trusses and a bottom chord. The design uses vertical members for compression and diagonal members to respond to tension. The ones in the photo above are in a heritage building of around the 1950 s fannie bay gaol darwin nt.

Mechanics forces acceleration displacement vectors motion momentum energy of objects and more. Beams and columns deflection and stress moment of inertia section modulus and technical information of beams and columns. This free online truss calculator is a truss design tool that generates the axial forces reactions of completely customisable 2d truss structures or rafters.