Recent research on steel-concrete composite shell roofs

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. Intensive research is currently being conducted by the authors on the behaviour and design of these composite shell roofs. This paper provides a description of this new structural system and a summary of current research on the various possible failure modes of this system.