I think this does give the pratt an advantage but read my best bridge design article more for information.
Pratt truss roof details.
Fan truss it is made of steel.
It offers a new alternative in prefabrication and field assembly methods without basic departures from established.
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 roots of the pratt truss involved using iron not wood for the angled members.
Roof truss span tables alpine engineered products 15 top chord 2x4 2x6 2x6 2x4 2x6 2x6 2x4 2x6 2x6 2x4 2x6 2x6 bottom chord 2x4 2x4 2x6 2x4 2x4 2x6 2x4 2x4 2x6 2x4 2x4 2x6 2 12 24 24 33 27 27 37 31 31 43 33 33 46 2 5 12 29 29 39 33 33 45 37 38 52 39 40 55 3 12 34 34 46 37 39 53 40 44 60 43 46 64 3 5 12 39 39 53 41 44 61 44 50 65 47 52 70.
Pratt truss pratt truss is made of steel.
It used wood for the vertical members.
Pratt truss this is one of the most popular steel roof truss types and it is quite economical.
There are six main types of roof trusses as listed below.
These can vary a lot.
These are very economical form of roof trusses.
This article and series of illustrated diagrams shows you all the parts of a basic roof truss king truss and queen truss.
The roof truss structure and design is integral to roof structural integrity and shape.
Better yet build your own pratt and howe truss bridges and compare their strength on your own.
In a conventional pratt truss diagonal members are in tension for gravity loads.
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.
There are many types of roof trusses as wall as many types of roofs more types than there are parts.
This type of truss is used where gravity loads are predominant see below left.
For further details on how the loads are calculated on a truss and other design details please read this.
However with most model bridges you are just using wood.
It can be used for spans from 6 10m.
A roof truss based on two pratt trusses and a bottom chord.
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.
The ones in the photo above are in a heritage building of around the 1950 s fannie bay gaol darwin nt.