Recent research on steel-concrete composite shell roofs : buckling experiments on the steel base shell during construction

Steel-concrete composite shell roofs (Comshell roofs) are formed by pouring concrete on a thin stiffened steel base shell which serves as both the permanent formwork and the tensile steel reinforcement. The thin steel base shell, constructed by bolting together open-topped modular units consisting of a base plate with surrounding edge plates, is a steel shell with thin stiffeners in both directions. The new system retains all the benefits of thin concrete shells, but eliminates the need for temporary formwork and minimises the required falsework. In this paper, the structural features and possible failure modes of this new structural system are first outlined. The results of a series of buckling experiments on model steel base shells under simulated wet concrete loading during construction are then presented.