Ground and structure
Truss
techo warehouse gymnasium bridge
It is a structure of bars joined in triangles that forms the slope of the roof or spans a large distance.
What it solves
It covers wide spans with little material because each bar works in tension or compression. It gives the roof a slope to shed tropical rain quickly.
Today
Anchor each truss firmly to walls or columns, because strong wind tends to lift the roof. Brace the trusses to each other so they do not overturn.
Common mistake
Cutting a diagonal of the truss to gain space in the attic, so that it stops working as a triangle.
Tomorrow
Trusses with bolted joints can be dismantled and reassembled on another roof. Marking each piece during assembly makes that reuse easier years later.
Where it comes from
- 1Ancient Rome portico of the Pantheon, Rome, 2nd century
Its bronze king-post truss is the first certain case of this type of truss. - 2Saint Catherine’s Monastery Sinai, Egypt, 548 to 565
It preserves the oldest roof truss still standing, made of timber with a king post. - 3Bridges of the industrial era United States and Europe, 19th and 20th centuries
Trusses of timber, and later of iron and steel, crossed rivers and railways.
Masters
- Diébédo Francis Kéré Gando Primary School, Burkina Faso, 2001
He raises the metal sheet roof on light trusses of steel rebar assembled on site. With simple parts and basic tools he manages to cover the classrooms and separate the roof from the ceiling.
See also
Also in Ground and structure
Diagrams and texts by LDB Arquitectura. They are shared under the CC BY 4.0 license, which allows them to be used and adapted with credit to the source.