Summary
Tests which have been carried out on a one-tenth scale model of a hyperbolic paraboloid shell roof have given data from which the tie-bar force, corner reactions, deflexion and stress distribution of the actual structure have been calculated.
In the interior of the shell, the stresses calculated are in good agreement with those calculated by the membrane theory. Near the edge beams both the forces and the moments increase rapidly; since, however, the edges of the shell were thickened, the maximum stresses in the structure under a working load of 60 lb/ft2 were only 250 lb/in2 compression and 100 lb/in2 tension. At this load the maximum deflexion would be 0·5 in. The tie-bar force measured was only two-thirds of that predicted by the membrane theory, and equilibrium conditions revealed that the lower corners were carrying approximately 0·4 and the higher corners 0·1 of the total load.
The model shell had a load factor of at least 5.
