Pratt Truss Roof Details

For further details on how the loads are calculated on a truss and other design details please read this.

Pratt truss roof details.

A roof truss based on two pratt trusses and a bottom chord. These can vary a lot. Pratt trusses are commonly used in long span buildings ranging from 20 to 100 m in span. The ones in the photo above are in a heritage building of around the 1950 s fannie bay gaol darwin nt.

Flat truss with cantilever pratt configuration top chord bearing flat truss pratt configuration fl att rus w e nc of ig s l op i ngp are ch ds h w f u t sloping top chord howe configuration floor truss system 42 modified warren configuration mono trusses scissors mono mono parts of a truss framed roof gable end valley set gi rde. However with most model bridges you are just using wood. Fan truss it is made of steel. This article and series of illustrated diagrams shows you all the parts of a basic roof truss king truss and queen truss.

In a conventional pratt truss diagonal members are in tension for gravity loads. Vertical members are tension and diagonal members are compression. There are six main types of roof trusses as listed below. Pratt truss this is one of the most popular steel roof truss types and it is quite economical.

Better yet build your own pratt and howe truss bridges and compare their strength on your own. The roof truss structure and design is integral to roof structural integrity and shape. 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. These are very economical form of roof trusses.

The roots of the pratt truss involved using iron not wood for the angled members. 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. The truss framed system tfs is a new light frame wood construction concept that inte grates customary construction components roof trusses floor trusses and wall studs into unitized frames. Pratt truss pratt truss is made of steel.

It can be used for spans from 6 10m. I think this does give the pratt an advantage but read my best bridge design article more for information. This type of truss is used where gravity loads are predominant see below left. It used wood for the vertical members.