Investigation of the strength of reinforced-concrete shells of positive curvature

Conclusions

• 1. Smooth reinforced-concrete shells of positive curvature have high carryling capacity when acted upon by concentrated forces.

• 2. Distributing the load over the circumference of a circle, even a small one, makes it possible to increase by a considerable factor, 2 to 4 or even more, the carrying capacity of smooth shells acted upon by local loads.

• 3. An increase in the carrying capacity of smooth shells may be achieved by increasing the thickness of the slab in the zones of application of the loads and by positioning the reinforcement network in such a way that the cross sections of the structure can take the maximum meridional and annular normal forces and moments.

• 4. Calculation of the strength of shells in accordance with the proposed method yields results which agree satisfactorily with experimental results, and its use in design work can therefore be recommended. However, in view of the fact that the structures are subjected to considerable deflection before failure, the limiting load obtained by the method described should be decreased by 25–30%.