The basic roof truss consists of two rafters or struts and a restraining tie. Both rafters are pivoted at their apex.
The other end of one of the rafters is pivoted to a free standing base, whilst the remaining rafter end runs on ball bearings along a track.
When a load is hung from the apex, the free end of the rafter moves sideways, restrained by a spring balance tie.
Both rafters also include spring balances so that all internal loads can be directly measured.
Table-top experiment for resolving forces and analysing their distribution in simple frameworks
Number of nodes and members: 3
Dial gauge
Set of weights.